Publications by authors named "Loretta Gammaitoni"

45 Publications

CSPG4-Specific CAR.CIK Lymphocytes as a Novel Therapy for the Treatment of Multiple Soft-Tissue Sarcoma Histotypes.

Clin Cancer Res 2020 Dec 8;26(23):6321-6334. Epub 2020 Sep 8.

Candiolo Cancer Institute, FPO-IRCCS, Candiolo, Turin, Italy.

Purpose: No effective therapy is available for unresectable soft-tissue sarcomas (STS). This unmet clinical need prompted us to test whether chondroitin sulfate proteoglycan 4 (CSPG4)-specific chimeric antigen receptor (CAR)-redirected cytokine-induced killer lymphocytes (CAR.CIK) are effective in eliminating tumor cells derived from multiple STS histotypes and in immunodeficient mice.

Experimental Design: The experimental platform included patient-derived CAR.CIK and cell lines established from multiple STS histotypes. CAR.CIK were transduced with a retroviral vector encoding second-generation CSPG4-specific CAR (CSPG4-CAR) with 4-1BB costimulation. The functional activity of CSPG4-CAR.CIK was explored , in two- and three-dimensional STS cultures, and in three STS xenograft models.

Results: CSPG4-CAR.CIK were efficiently generated from patients with STS. CSPG4 was highly expressed in multiple STS histotypes by analysis and on all 16 STS cell lines tested by flow cytometry. CSPG4-CAR.CIK displayed superior cytolytic activity against multiple STS histotypes as compared with paired unmodified control CIK. CSPG4-CAR.CIK also showed strong antitumor activity against STS spheroids; this effect was associated with tumor recruitment, infiltration, and matrix penetration. CSPG4-CAR.CIK significantly delayed or reversed tumor growth in three STS xenograft models (leiomyosarcoma, undifferentiated pleomorphic sarcoma, and fibrosarcoma). Tumor growth inhibition persisted for up to 2 weeks following the last administration of CSPG4-CAR.CIK.

Conclusions: This study has shown that CSPG4-CAR.CIK effectively targets multiple STS histotypes and in immunodeficient mice. These results provide a strong rationale to translate the novel strategy we have developed into a clinical setting.
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http://dx.doi.org/10.1158/1078-0432.CCR-20-0357DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7710537PMC
December 2020

CAR-Based Strategies beyond T Lymphocytes: Integrative Opportunities for Cancer Adoptive Immunotherapy.

Int J Mol Sci 2019 Jun 11;20(11). Epub 2019 Jun 11.

Department of Oncology, University of Torino, 10140 Torino, Italy.

Chimeric antigen receptor (CAR)-engineered T lymphocytes (CAR Ts) produced impressive clinical results against selected hematological malignancies, but the extension of CAR T cell therapy to the challenging field of solid tumors has not, so far, replicated similar clinical outcomes. Many efforts are currently dedicated to improve the efficacy and safety of CAR-based adoptive immunotherapies, including application against solid tumors. A promising approach is CAR engineering of immune effectors different from αβT lymphocytes. Herein we reviewed biological features, therapeutic potential, and safety of alternative effectors to conventional CAR T cells: γδT, natural killer (NK), NKT, or cytokine-induced killer (CIK) cells. The intrinsic CAR-independent antitumor activities, safety profile, and ex vivo expansibility of these alternative immune effectors may favorably contribute to the clinical development of CAR strategies. The proper biological features of innate immune response effectors may represent an added value in tumor settings with heterogeneous CAR target expression, limiting the risk of tumor clonal escape. All these properties bring out CAR engineering of alternative immune effectors as a promising integrative option to be explored in future clinical studies.
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http://dx.doi.org/10.3390/ijms20112839DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6600566PMC
June 2019

Met inhibition revokes IFNγ-induction of PD-1 ligands in MET-amplified tumours.

Br J Cancer 2019 03 6;120(5):527-536. Epub 2019 Feb 6.

Medical Oncology Division, Experimental Cell Therapy, Candiolo Cancer Institute, FPO-IRCCS, Candiolo, Torino, Italy.

Background: Interferon-induced expression of programmed cell death ligands (PD-L1/PD-L2) may sustain tumour immune-evasion. Patients featuring MET amplification, a genetic lesion driving transformation, may benefit from anti-MET treatment. We explored if MET-targeted therapy interferes with Interferon-γ modulation of PD-L1/PD-L2 in MET-amplified tumours.

Methods: PD-L1/PD-L2 expression and signalling pathways downstream of MET or Interferon-γ were analysed in MET-amplified tumour cell lines and in patient-derived tumour organoids, in basal condition, upon Interferon-γ stimulation, and after anti-MET therapy.

Results: PD-L1 and PD-L2 were upregulated in MET-amplified tumour cells upon Interferon-γ treatment. This induction was impaired by JNJ-605, a selective inhibitor of MET kinase activity, and MvDN30, an antibody inducing MET proteolytic cleavage. We found that activation of JAKs/ STAT1, signal transducers downstream of the Interferon-γ receptor, was neutralised by MET inhibitors. Moreover, JAK2 and MET associated in the same signalling complex depending on MET phosphorylation. Results were confirmed in MET-amplified organoids derived from human colorectal tumours, where JNJ-605 treatment revoked Interferon-γ induced PD-L1 expression.

Conclusions: These data show that in MET-amplified cancers, treatment with MET inhibitors counteracts the induction of PD-1 ligands by Interferon-γ. Thus, therapeutic use of anti-MET drugs may provide additional clinical benefit over and above the intended inhibition of the target oncogene.
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http://dx.doi.org/10.1038/s41416-018-0315-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6461865PMC
March 2019

Cytokine Induced Killer cells are effective against sarcoma cancer stem cells spared by chemotherapy and target therapy.

Oncoimmunology 2018;7(11):e1465161. Epub 2018 Aug 6.

Medical Oncology Division, Candiolo Cancer Institute, FPO-IRCCS. Str. Prov. 142, km 3.95, I-10060, Candiolo (To), Italy.

Metastatic bone and soft tissue sarcomas often relapse after chemotherapy (CHT) and molecular targeted therapy (mTT), maintaining a severe prognosis. A subset of sarcoma cancer stem cells (sCSC) is hypothesized to resist conventional drugs and sustain disease relapses. We investigated the immunotherapy activity of cytokine induced killer cells (CIK) against autologous sCSC that survived CHT and mTT. The experimental platform included two aggressive bone and soft tissue sarcoma models: osteosarcoma (OS) and undifferentiated-pleomorphic sarcoma (UPS). To visualize putative sCSC we engineered patient-derived sarcoma cultures (2 OS and 3 UPS) with a lentiviral sCSC-detector wherein the promoter of stem-gene Oct4 controls the expression of eGFP. We visualized a fraction of sCSC (mean 24.2 ± 5.2%) and confirmed their tumorigenicity . sCSC resulted relatively resistant to both CHT and mTT . Therapeutic doses of doxorubicin significantly enriched viable eGFPsCSC in both OS (2.6 fold, n = 16) and UPS (2.3 fold, n = 29) compared to untreated controls. Treatment with sorafenib (for OS) and pazopanib (for UPS) also determined enrichment (1.3 fold) of viable eGFPsCSC, even if less intense than what observed after CHT. Sarcoma cells surviving CHT and mTT were efficiently killed by autologous CIK even at minimal effector/target ratios (40:1 = 82%, 1:4 = 29%, n = 13). CIK immunotherapy did not spare sCSC that were killed as efficiently as whole sarcoma cell population. The relative chemo-resistance of sCSC and sensitivity to CIK immunotherapy was confirmed . Our findings support CIK as an innovative, clinically explorable, approach to eradicate chemo-resistant sCSC implicated in tumor relapse.
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http://dx.doi.org/10.1080/2162402X.2018.1465161DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6208452PMC
August 2018

BRAF and MEK Inhibitors Increase PD-1-Positive Melanoma Cells Leading to a Potential Lymphocyte-Independent Synergism with Anti-PD-1 Antibody.

Clin Cancer Res 2018 07 12;24(14):3377-3385. Epub 2018 Apr 12.

Department of Oncology, University of Turin, Turin, Italy.

BRAF and MEK inhibitors (BRAF/MEKi) favor melanoma-infiltrating lymphocytes, providing the rationale for current combinatorial trials with anti-PD-1 antibody. A portion of melanoma cells may express PD-1, and anti-PD-1 antibody could have a direct antitumor effect. Here, we explore whether BRAF/MEKi modulate rates of PD-1 melanoma cells, supporting an additional-lymphocyte-independent-basis for their therapeutic combination with anti-PD-1 antibody. With data mining and flow cytometry, we assessed PD-1, PD-L1/2 expression on melanoma cell lines (CCLE, = 61; validation cell lines, = 7) and melanoma tumors (TCGA, = 214). We explored how BRAF/MEKi affect rates of PD-1, PD-L1/2 melanoma cells, and characterized the proliferative and putative stemness features of PD-1 melanoma cells. We tested the functional lymphocyte-independent effect of anti-PD-1 antibody alone and in combination with BRAF/MEKi and in an immunodeficient murine model. PD-1 is consistently expressed on a small subset of melanoma cells, but PD-1 cells increase to relevant rates during BRAF/MEKi treatment [7.3% (5.6-14.2) vs. 1.5% (0.7-3.2), = 0.0156; = 7], together with PD-L2 melanoma cells [8.5% (0.0-63.0) vs. 1.5% (0.2-43.3), = 0.0312; = 7]. PD-1 cells proliferate less than PD-1 cells (avg. 65% less; = 7 days) and are preferentially endowed with stemness features. , the direct anti-melanoma activity of PD-1 blockage as monotherapy was negligible, but its association with BRAF/MEKi significantly delayed the development of drug resistance and tumor relapse. BRAF/MEKi increase the rates of PD-1 melanoma cells that may sustain tumor relapse, providing a lymphocyte-independent rationale to explore combinatory strategies with anti-PD-1 antibody. .
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http://dx.doi.org/10.1158/1078-0432.CCR-17-1914DOI Listing
July 2018

Prognostic and predictive role of EGFR pathway alterations in biliary cancer patients treated with chemotherapy and anti-EGFR.

PLoS One 2018 19;13(1):e0191593. Epub 2018 Jan 19.

Medical Oncology, Fondazione del Piemonte per l'Oncologia (FPO), IRCCS-Institute of Candiolo, Candiolo, Italy.

The association of anti-EGFR to gemcitabine and oxaliplatin (GEMOX) chemotherapy did not improve survival in biliary tract carcinoma (BTC) patients. Multiple mechanisms might be involved in the resistance to anti-EGFR. Here, we explored the mutation profile of EGFR extracellular domain (ECD), of tyrosine kinase domain (TKD), and its amplification status. EGFR mutational status of exons 12, 18-21 was analyzed in 57 tumors by Sanger sequencing. EGFR amplification was evaluated in 37 tumors by Fluorescent In Situ Hybridization (FISH). Kaplan-Meier curves were calculated using the log-rank test. Six patients had mutations in exon 12 of EGFR ECD and 7 in EGFR TKD. Neither EGFR ECD nor TKD mutations affected progression free survival (PFS) or overall survival (OS) in the entire population. In the panitumumab plus GEMOX (P-GEMOX) arm, ECD mutated patients had a worse OS, while EGFR TKD mutated patients had a trend towards shorter PFS and OS. Overall, the presence of mutations in EGFR or in its transducers did not affect PFS or OS, while the extrahepatic cholangiocarcinoma (ECC) mutated patients had a worse prognosis compared to WT. Nineteen out of 37 tumors were EGFR amplified, but the amplification did not correlate with survival. ECC EGFR amplified patients had improved OS, whereas the amplification significantly correlated with poor PFS (p = 0.03) in gallbladder carcinoma patients. The high molecular heterogeneity is a predominant feature of BTC: the alterations found in this work seem to have a prognostic impact rather than a predictive role towards anti-EGFR therapy.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0191593PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5774843PMC
February 2018

BRAF-inhibitors can exert control of disease in BRAF T599I mutated melanoma: a case report.

Melanoma Res 2018 04;28(2):143-146

Medical Oncology.

BRAF signaling is involved in melanoma growth in more than half of metastatic patients. In the last few years, new drugs that block this pathway have significantly improved the outcomes of patients with metastatic melanoma. Ninety percent of BRAF mutations involve exon 15, and the most frequent, V600E, results from the amino acid change from valine (V) to glutamic acid (E). BRAF inhibitor treatments have shown a notable overall response rate and improvements in progression-free and overall survival. Rare BRAF mutations of codon 599 have been also described in a few patients with papillary thyroid cancer and melanoma. Nowadays, no evidence is available in the literature, describing the role of target therapies as treatment in patients with this specific codon mutation. We describe the case of a young woman with metastatic melanoma with a particular BRAF mutation, T599I, who has benefited from treatment with a BRAF inhibitor, vemurafenib.
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http://dx.doi.org/10.1097/CMR.0000000000000417DOI Listing
April 2018

PARP1 expression drives the synergistic antitumor activity of trabectedin and PARP1 inhibitors in sarcoma preclinical models.

Mol Cancer 2017 04 28;16(1):86. Epub 2017 Apr 28.

Sarcoma Unit, Medical Oncology, Candiolo Cancer Institute - FPO, IRCCS, Candiolo, Torino, Italy.

Background: Enhancing the antitumor activity of the DNA-damaging drugs is an attractive strategy to improve current treatment options. Trabectedin is an isoquinoline alkylating agent with a peculiar mechanism of action. It binds to minor groove of DNA inducing single- and double-strand-breaks. These kinds of damage lead to the activation of PARP1, a first-line enzyme in DNA-damage response pathways. We hypothesized that PARP1 targeting could perpetuate trabectedin-induced DNA damage in tumor cells leading finally to cell death.

Methods: We investigated trabectedin and PARP1 inhibitor synergism in several tumor histotypes both in vitro and in vivo (subcutaneous and orthotopic tumor xenografts in mice). We searched for key determinants of drug synergism by comparative genomic hybridization (aCGH) and gene expression profiling (GEP) and validated their functional role.

Results: Trabectedin activated PARP1 enzyme and the combination with PARP1 inhibitors potentiated DNA damage, cell cycle arrest at G2/M checkpoint and apoptosis, if compared to single agents. Olaparib was the most active PARP1 inhibitor to combine with trabectedin and we confirmed the antitumor and antimetastatic activity of trabectedin/olaparib combination in mice models. However, we observed different degree of trabectedin/olaparib synergism among different cell lines. Namely, in DMR leiomyosarcoma models the combination was significantly more active than single agents, while in SJSA-1 osteosarcoma models no further advantage was obtained if compared to trabectedin alone. aCGH and GEP revealed that key components of DNA-repair pathways were involved in trabectedin/olaparib synergism. In particular, PARP1 expression dictated the degree of the synergism. Indeed, trabectedin/olaparib synergism was increased after PARP1 overexpression and reduced after PARP1 silencing.

Conclusions: PARP1 inhibition potentiated trabectedin activity in a PARP1-dependent manner and PARP1 expression in tumor cells might be a useful predictive biomarker that deserves clinical evaluation.
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http://dx.doi.org/10.1186/s12943-017-0652-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5410089PMC
April 2017

Role of interferon in melanoma: old hopes and new perspectives.

Expert Opin Biol Ther 2017 04 16;17(4):475-483. Epub 2017 Feb 16.

a Department of Oncology , University of Torino , Candiolo , Torino , Italy.

Introduction: Interferons (IFNs) play a key role in modulating anti-microbial and antitumor immune responses. In oncology, past attempts to exploit IFNs therapeutically did not fulfill expectations, and had only modest clinical results, mostly limited to adjuvant melanoma treatment. The recent successes of immunotherapy in oncology have brought new attention to the potential of immune-modulatory agents like the IFNs. Areas covered: The authors review the biological effects of IFN on melanoma and immune cells. Then, the authors summarize the clinical results of adjuvant and therapeutic IFN in melanoma, giving focus to possible prognostic factors and new on-going clinical trials. Expert opinion: IFNs offer intriguing opportunities for synergism between conventional treatments and recently introduced molecular-targeted and immunotherapy approaches. However, the full comprehension of all IFN effects and their multiple biologic links is challenging. A strong commitment toward parallel translational research is needed to facilitate the interpretation of IFN's expected and unexpected effects, guiding the rational design of informative clinical studies.
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http://dx.doi.org/10.1080/14712598.2017.1289169DOI Listing
April 2017

Post-Transplant Cyclophosphamide and Tacrolimus-Mycophenolate Mofetil Combination Prevents Graft-versus-Host Disease in Allogeneic Peripheral Blood Hematopoietic Cell Transplantation from HLA-Matched Donors.

Biol Blood Marrow Transplant 2017 Mar 27;23(3):459-466. Epub 2016 Dec 27.

Medical Oncology, Hematopoietic Stem Cells Unit, Turin Metropolitan Transplant Center, Candiolo Cancer Institute-FPO, IRCCS, Candiolo, Italy; Department of Oncology, University of Torino, Turin, Italy; Department of Medical Oncology, Candiolo Cancer Institute-FPO, IRCCS, Candiolo, Italy.

Allogeneic hematopoietic cell transplant (HCT) remains the only curative therapy for many hematologic malignancies but it is limited by high nonrelapse mortality (NRM), primarily from unpredictable control of graft-versus-host disease (GVHD). Recently, post-transplant cyclophosphamide demonstrated improved GVHD control in allogeneic bone marrow HCT. Here we explore cyclophosphamide in allogeneic peripheral blood stem cell transplantation (alloPBSCT). Patients with high-risk hematologic malignancies received alloPBSCT from HLA-matched unrelated/related donors. GVHD prophylaxis included combination post-HCT cyclophosphamide 50 mg/kg (days +3 and +4) and tacrolimus/mofetil mycophenolate (T/MMF) (day +5 forward). The primary objective was the cumulative incidence of acute and chronic GVHD. Between March 2011 and May 2015, 35 consecutive patients received the proposed regimen. MMF was stopped in all patients at day +28; the median discontinuation of tacrolimus was day +113. Acute and chronic GVHD cumulative incidences were 17% and 7%, respectively, with no grade IV GVHD events, only 2 patients requiring chronic GVHD immunosuppression control, and no deaths from GVHD. Two-year NRM, overall survival, event-free survival, and chronic GVHD event-free survival rates were 3%, 77%, 54%, and 49%, respectively. The graft-versus-tumor effect was maintained as 5 of 15 patients (33%) who received HCT with evidence of disease experienced further disease response. A post-transplant cyclophosphamide + T/MMF combination strategy effectively prevented acute and chronic GVHD after alloPBSCT from HLA-matched donors and achieved an unprecedented low NRM without losing efficacy in disease control or impaired development of the graft-versus-tumor effect. This trial is registered at clinicaltrials.gov as NCT02300571.
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http://dx.doi.org/10.1016/j.bbmt.2016.12.636DOI Listing
March 2017

Cytokine-Induced Killer Cells Kill Chemo-surviving Melanoma Cancer Stem Cells.

Clin Cancer Res 2017 May 4;23(9):2277-2288. Epub 2016 Nov 4.

Division of Medical Oncology, Experimental Cell Therapy, Candiolo Cancer Institute, FPO-IRCCS, Candiolo, Torino, Italy.

The MHC-unrestricted activity of cytokine-induced killer (CIK) cells against chemo-surviving melanoma cancer stem cells (mCSC) was explored, as CSCs are considered responsible for chemoresistance and relapses. Putative mCSCs were visualized by engineering patient-derived melanoma cells (MC) with a lentiviral vector encoding eGFP under expression control by stemness gene promoter Their stemness potential was confirmed by limiting dilution assays. We explored the sensitivity of eGFP mCSCs to chemotherapy (CHT), BRAF inhibitor (BRAFi) or CIK cells, as single agents or in sequence, First, we treated MCs with fotemustine or dabrafenib (BRAF-mutated cases); then, surviving MCs, enriched in mCSCs, were challenged with autologous CIK cells. CIK cell activity against chemoresistant mCSCs was confirmed in two distinct immunodeficient murine models. We visualized eGFP mCSCs (14% ± 2.1%) in 11 MCs. The tumorigenic precursor rate was higher within eGFP MCs (1/42) compared with the eGFP counterpart (1/4,870). mCSCs were relatively resistant to CHT and BRAFi, but killed by CIK cells ( = 11, 8/11 autologous), with specific lysis ranging from 95% [effector:tumor ratio (E:T), 40:1] to 20% (E:T 1:3). infusion of autologous CIK cells into mice bearing xenografts from three distinct melanomas demonstrated significant tumor responses involving CHT-spared eGFP mCSCs ( = 0.001). Sequential CHT-immunotherapy treatment retained antitumor activity ( = 12, = 0.001) reducing mCSC rates ( = 0.01). These findings are the first demonstration that immunotherapy with CIK cells is active against autologous mCSCs surviving CHT or BRAFi. An experimental platform for mCSC study and rationale for CIK cells in melanoma clinical study is provided. .
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http://dx.doi.org/10.1158/1078-0432.CCR-16-1524DOI Listing
May 2017

Cytokine-induced killer cells as immunotherapy for solid tumors: current evidence and perspectives.

Immunotherapy 2015 27;7(9):999-1010. Epub 2015 Aug 27.

Department of Oncology, University of Torino, Turin, Italy.

Cytokine-induced killer (CIK) cells are ex vivo expanded T lymphocytes endowed with potent MHC-independent antitumor activity. CIK cells are emerging as promising therapeutic approach in the field of cancer adoptive immunotherapy, with biologic features favoring their transferability into clinical applications. Aim of this review is to present the biologic characteristic of CIK cells, discussing the main preclinical findings and initial clinical applications in the field of solid tumors.
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http://dx.doi.org/10.2217/imt.15.61DOI Listing
August 2016

Synergy of molecular targeted approaches and immunotherapy in melanoma: preclinical basis and clinical perspectives.

Expert Opin Biol Ther 2015 24;15(10):1491-500. Epub 2015 Jul 24.

b 2 University of California San Francisco, Mt. Zion Cancer Research Center , 2340 Sutter Street N461, San Francisco, CA, USA.

Introduction: Targeted therapy and immunotherapies are the novel pharmacologic treatment strategies for metastatic melanoma. BRAF and MEK inhibitors effectively block the hyperactivation of the MAPK pathway in BRAF mutant melanomas and also have several other effects on melanoma cells and on the immune response. The aim of this work is to discuss the rationale, evidence and perspectives of approaches combining target and immunotherapy against melanoma.

Areas Covered: We first review the effects of BRAF and MEK inhibitors on melanoma cells and on the different components of the immune system. Afterwards, we summarize the results of the preclinical and clinical studies that have combined targeted therapy and immunotherapy for the treatment of melanoma.

Expert Opinion: Clinical applications of immunotherapy strategies have recently changed the therapeutic mainstay for metastatic melanoma. Biologic and initial preclinical data support their integration with innovative molecular targeted therapies, opening enormous perspectives for researchers in the effort of finding a definitive cure. Main open challenges are the definition of reliable research models, assessment of effective schedules, safety issues and designing of personalized approaches.
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http://dx.doi.org/10.1517/14712598.2015.1069272DOI Listing
April 2016

The combination of sorafenib and everolimus shows antitumor activity in preclinical models of malignant pleural mesothelioma.

BMC Cancer 2015 May 8;15:374. Epub 2015 May 8.

Department of Molecular Medicine, - Section of Pneumology, Laboratory of Biochemistry & Genetics, University and Fondazione IRCCS Policlinico San Matteo, Pavia, 27100, Italy.

Background: Malignant Pleural Mesothelioma (MPM) is an aggressive tumor arising from mesothelial cells lining the pleural cavities characterized by resistance to standard therapies. Most of the molecular steps responsible for pleural transformation remain unclear; however, several growth factor signaling cascades are known to be altered during MPM onset and progression. Transducers of these pathways, such as PIK3CA-mTOR-AKT, MAPK, and ezrin/radixin/moesin (ERM) could therefore be exploited as possible targets for pharmacological intervention. This study aimed to identify 'druggable' pathways in MPM and to formulate a targeted approach based on the use of commercially available molecules, such as the multikinase inhibitor sorafenib and the mTOR inhibitor everolimus.

Methods: We planned a triple approach based on: i) analysis of immunophenotypes and mutational profiles in a cohort of thoracoscopic MPM samples, ii) in vitro pharmacological assays, ii) in vivo therapeutic approaches on MPM xenografts. No mutations were found in 'hot spot' regions of the mTOR upstream genes (e.g. EGFR, KRAS and PIK3CA).

Results: Phosphorylated mTOR and ERM were specifically overexpressed in the analyzed MPM samples. Sorafenib and everolimus combination was effective in mTOR and ERM blockade; exerted synergistic effects on the inhibition of MPM cell proliferation; triggered ROS production and consequent AMPK-p38 mediated-apoptosis. The antitumor activity was displayed when orally administered to MPM-bearing NOD/SCID mice.

Conclusions: ERM and mTOR pathways are activated in MPM and 'druggable' by a combination of sorafenib and everolimus. Combination therapy is a promising therapeutic strategy against MPM.
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http://dx.doi.org/10.1186/s12885-015-1363-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4429519PMC
May 2015

Cytokine-induced killer cells engineered with exogenous T-cell receptors directed against melanoma antigens: enhanced efficacy of effector cells endowed with a double mechanism of tumor recognition.

Hum Gene Ther 2015 Apr 13;26(4):220-31. Epub 2015 Apr 13.

1 Molecular Biotechnology Center, University of Torino , 10126 Turin, Italy .

Cytokine-induced killer (CIK) cells consist of a heterogeneous population of polyclonal T lymphocytes displaying NK phenotype and HLA-unrestricted cytotoxic activity against a broad range of tumors. We sought to determine whether transduction of CIK cells with T cell receptor (TCR) genes specific for tumor-associated antigens could generate effector cells endowed with a double mechanism of tumor recognition. HLA-A2-restricted TCR-transduced (TD) CIK directed against the melanoma antigens Mart1 and NY-ESO1 were generated by lentiviral transduction and successfully expanded over a 3-4-week period. TD-CIK cells were both CD3(+)/CD56(-) and CD3(+)/CD56(+) (31±8% and 59±9%, respectively), indicating that both major histocompatibility complex (MHC)-restricted T cells and MHC-unrestricted CIK could be targeted by lentiviral transduction. At the end of the culture, the majority of both unmodified and TD-CIK displayed an effector memory phenotype, without considerable expression of replicative senescence and exhaustion markers. Functionally, TD-CIK specifically recognized tumor cells expressing the relevant antigen as well as maintained their MHC-unrestricted tumor activity. The cytotoxic activity of TD-CIK against HLA-A2(+) melanoma cell lines was significantly higher than the untransduced counterparts at a low effector:target ratio (cytotoxic activity of TD-CIK was from 1.9- to 4.3-fold higher than untransduced counterparts). TD-CIK were highly proficient in releasing high amount of IFN-γ upon antigen-specific stimulation and were able to recognize primary melanoma targets. In conclusion, we showed that (1) the reproducibility and simplicity of CIK transduction and expansion might solve the problem of obtaining adequate numbers of potent antitumor effector cells for adoptive immunotherapy; (2) the presence of both terminal effectors as well as of less differentiated progenitors might confer them long survival in vivo; and (3) the addition of an MHC-restricted antigen recognition allows not only targeting tumor surface antigens but also a wider range of cytoplasmic or nuclear antigens, involved in tumor proliferation and survival. TD-CIK cells with a double mechanism of tumor recognition are an attractive and alternative tool for the development of efficient cell therapeutic strategies.
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http://dx.doi.org/10.1089/hum.2014.112DOI Listing
April 2015

Adoptive immunotherapy against sarcomas.

Expert Opin Biol Ther 2015 Apr 16;15(4):517-28. Epub 2014 Dec 16.

Candiolo Cancer Institute-IRCCS, Laboratory of Medical Oncology, Experimental Cell Therapy , Candiolo, Turin , Italy.

Introduction: Conventional treatments reached an unsatisfactory therapeutic plateau in the treatment of advanced unresectable bone and soft tissue sarcomas that remain an unsolved medical need. Several evidences support the concept that adoptive immunotherapy may effectively integrate within the complex and multidisciplinary treatment of sarcomas.

Areas Covered: In this work we reviewed adoptive immunotherapy strategies that have been explored in sarcoma settings, with specific focus on issues related to their clinic transferability. We schematically divided approaches based on T lymphocytes specific for MHC-restricted tumor-associated antigens or relying on MHC-independent immune effectors such as natural killer (NK), cytokine-induced killer (CIK) or γδ T cells.

Expert Opinion: Preclinical findings and initial clinical reports showed the potentialities and drawbacks of different adoptive immunotherapy strategies. The expansion of tumor infiltrating lymphocytes is difficult to be reproduced outside melanoma. Genetically redirected T cells appear to be a promising option and initial reports are encouraging against patients with sarcomas. Adoptive immunotherapy with MHC-unrestricted effectors such as NK, CIK or γδ T cells has recently shown great preclinical potential in sarcoma setting and biologic features that may favor clinical transferability. Combination of different immunotherapy approaches and integration with conventional treatments appear to be key issues for successful designing of next clinical trials.
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http://dx.doi.org/10.1517/14712598.2015.987121DOI Listing
April 2015

Anti-cancer effect and gene modulation of ET-743 in human biliary tract carcinoma preclinical models.

BMC Cancer 2014 Dec 5;14:918. Epub 2014 Dec 5.

University of Turin Medical School, Department of Oncology, IRCCS-Candiolo, Strada provinciale 142, Km 3,95, Candiolo, 10060 Turin, Italy.

Background: Standard chemotherapy in unresectable biliary tract carcinoma (BTC) patients is based on gemcitabine combined with platinum derivatives. However, primary or acquired resistance is inevitable and no second-line chemotherapy is demonstrated to be effective. Thus, there is an urgent need to identify new alternative (chemo)therapy approaches.

Methods: We evaluated the mechanism of action of ET-743 in preclinical models of BTC. Six BTC cell lines (TFK-1, EGI-1, TGBC1, WITT, KMCH, HuH28), two primary cell cultures derived from BTC patients, the EGI-1 and a new established BTC patient-derived xenografts, were used as preclinical models to investigate the anti-tumor activity of ET-743 in vitro and in vivo. Gene expression profiling was also analyzed upon ET-743 treatment in in vivo models.

Results: We found that ET-743 inhibited cell growth of BTC cell lines and primary cultures (IC50 ranging from 0.37 to 3.08 nM) preferentially inducing apoptosis and activation of the complex DNA damage-repair proteins (p-ATM, p-p53 and p-Histone H2A.x) in vitro. In EGI-1 and patient-derived xenografts, ET-743 induced tumor growth delay and reduction of vasculogenesis. In vivo ET-743 induced a deregulation of genes involved in cell adhesion, stress-related response, and in pathways involved in cholangiocarcinogenesis, such as the IL-6, Sonic Hedgehog and Wnt signaling pathways.

Conclusions: These results suggest that ET-743 could represent an alternative chemotherapy for BTC treatment and encourage the development of clinical trials in BTC patients resistant to standard chemotherapy.
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http://dx.doi.org/10.1186/1471-2407-14-918DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4289395PMC
December 2014

Activity of cytokine-induced killer cells against bone and soft tissue sarcoma.

Oncoimmunology 2014;3:e28269. Epub 2014 Mar 17.

Division and Laboratory of Medical Oncology; Candiolo Cancer Institute-FPO; IRCCS Candiolo; Candiolo, Turin, Italy.

Cytokine-induced killer (CIK) cells are T lymphocytes expanded ex vivo that are endowed with MHC-independent tumoricidal activity. We have recently demonstrated, in a preclinical setting, that CIK cells are active against autologous bone and soft tissue sarcomas. In particular, CIK cells killed a putative sarcoma stem cell population that may underlie disease relapse and chemoresistance.
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http://dx.doi.org/10.4161/onci.28269DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4091097PMC
March 2014

Immunotherapy of cancer stem cells in solid tumors: initial findings and future prospective.

Expert Opin Biol Ther 2014 Sep 16;14(9):1259-70. Epub 2014 May 16.

Candiolo Cancer Institute-FPO, IRCCS , Candiolo, 10060 , Italy.

Introduction: Conventional chemotherapies seemed to have reached a therapeutic plateau in the treatment of solid tumors and many metastatic diseases are still incurable. Events of chemo-resistance and relapses appear to be sustained by a subset of putative cancer stem cells (CSCs). New anticancer strategies need to face this new challenge exploring their efficacy against CSCs. Immunotherapy has raised enthusiasms in cancer therapy and its potential against CSCs is an intriguing field of research.

Areas Covered: In this work we reviewed the immunotherapy approaches directed against CSCs in solid tumors. We schematically divided adaptive immunotherapy strategies, mainly based on dendritic cell-vaccination, and strategies exploiting MHC-unrestricted effectors like natural killer cells, γδ T lymphocytes and cytokine-induced killer cells. Findings, strength and limitations of these models are discussed and compared highlighting their potential clinical relevance.

Expert Opinion: The important biologic role and clinical relevance of CSCs introduced a 'noble target' for immunotherapy and cancer treatments in general. Initial evidences suggest that CSCs may be susceptible to various types of immunotherapy attacks, overcoming their chemo-resistance. Investigation of important safety issues, based on shared features with 'normal' stem cells, along with intriguing synergisms with modulatory agents are open challenges for the next future and effective clinical translation.
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http://dx.doi.org/10.1517/14712598.2014.918099DOI Listing
September 2014

Genetically redirected T lymphocytes for adoptive immunotherapy of solid tumors.

Curr Gene Ther 2014 Feb;14(1):52-62

Laboratory of Cell Therapy, Institute for Cancer Research and Treatment, Provinciale 142 - 10060 Candiolo, Torino Italy.

Genetic engineering of T lymphocytes to confer new antitumor specificities is a fascinating approach that may help the successful clinical translation of adoptive immunotherapy strategies. The recognition of tumor-specific antigens may be obtained inducing the membrane expression of transgene encoded antitumor T cell receptors (TCR) or chimeric antigen receptors (CAR). Few but very informative clinical trials with TCR or CAR redirected T lymphocytes have been attempted in the last years, reporting important clinical results along with disappointing failures and important warnings. In this work, we will focus on TCR and CAR redirected T lymphocytes as adoptive immunotherapy for solid tumors. We will review the main topics of these strategies from the angle of clinical applications, discussing the main issues that emerged from early clinical trials and their impact on next study designs.
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http://dx.doi.org/10.2174/1566523213666131223130353DOI Listing
February 2014

Cytokine-induced killer cells eradicate bone and soft-tissue sarcomas.

Cancer Res 2014 Jan 19;74(1):119-29. Epub 2013 Dec 19.

Authors' Affiliations: Stem Cell Transplantation and Cell Therapy, Pathology, Sarcoma, Fondazione del Piemonte per l'Oncologia, Laboratory of Molecular Pharmacology, Institute for Cancer Research and Treatment; Department of Oncology, University of Torino Medical School; and Division of Pediatric Onco-Hematology, Sant'Anna OIRM Hospital, (Torino), Italy.

Unresectable metastatic bone sarcoma and soft-tissue sarcomas (STS) are incurable due to the inability to eradicate chemoresistant cancer stem-like cells (sCSC) that are likely responsible for relapses and drug resistance. In this study, we investigated the preclinical activity of patient-derived cytokine-induced killer (CIK) cells against autologous bone sarcoma and STS, including against putative sCSCs. Tumor killing was evaluated both in vitro and within an immunodeficient mouse model of autologous sarcoma. To identify putative sCSCs, autologous bone sarcoma and STS cells were engineered with a CSC detector vector encoding eGFP under the control of the human promoter for OCT4, a stem cell gene activated in putative sCSCs. Using CIK cells expanded from 21 patients, we found that CIK cells efficiently killed allogeneic and autologous sarcoma cells in vitro. Intravenous infusion of CIK cells delayed autologous tumor growth in immunodeficient mice. Further in vivo analyses established that CIK cells could infiltrate tumors and that tumor growth inhibition occurred without an enrichment of sCSCs relative to control-treated animals. These results provide preclinical proof-of-concept for an effective strategy to attack autologous sarcomas, including putative sCSCs, supporting the clinical development of CIK cells as a novel class of immunotherapy for use in settings of untreatable metastatic disease.
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http://dx.doi.org/10.1158/0008-5472.CAN-13-1559DOI Listing
January 2014

Ex vivo-activated MHC-unrestricted immune effectors for cancer adoptive immunotherapy.

Anticancer Agents Med Chem 2014 Feb;14(2):211-22

Laboratory of Cell Therapy, Institute for Cancer Research and Treatment, Provinciale 142 - 10060 Candiolo, Torino Italy.

Adoptive immunotherapy is considered a promising strategy for the treatment of metastatic tumors and current research efforts are directed to define the optimal approach and facilitate the transferability from preclinical to clinical settings. Among several approaches it is possible to schematically distinguish strategies based on either MHC-restricted or MHC-unrestricted immune effectors. The first are mainly based on the infusion of tumor-specific T lymphocytes capable of recognizing determined MHC-restricted tumor associated antigens (TAA) through their T cell receptor. MHC-unrestricted approaches do not target specific tumor associated antigens and are mainly mediated by effectors of the innate immune system, like natural killer (NK) cells or NKT cells, first barrier against pathogens and tumorigenesis processes, or by ex vivo activated lymphocytes like cytokine-induced killer (CIK) cells. MHC-unrestricted effectors are usually more abundant than TAA-specific precursors and easier to expand. Furthermore their activity is not restricted to precise HLA-haplotypes, not limited to a single tumor histotype and could overcome downregulation of MHC molecules operated by tumor cells as immune escape mechanism. In this review we will discuss the main cancer immunotherapy strategies based on MHC-unrestricted immune effectors. The topic will be approached from the angle of ex vivo expansion protocols in clinical prospective, as well as potential approaches to favorably modulate their functions.
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http://dx.doi.org/10.2174/18715206113136660371DOI Listing
February 2014

Effective activity of cytokine-induced killer cells against autologous metastatic melanoma including cells with stemness features.

Clin Cancer Res 2013 Aug 21;19(16):4347-58. Epub 2013 Jun 21.

Unit of Stem Cell Transplantation and Cell Therapy, Surgical Dermatology, Pathology, and Sarcoma, Fondazione del Piemonte per l'Oncologia, I.R.C.C.S.,Torino, Italy.

Purpose: We investigate the unknown tumor-killing activity of cytokine-induced killer (CIK) cells against autologous metastatic melanoma and the elusive subset of putative cancer stem cells (mCSC).

Experimental Design: We developed a preclinical autologous model using same patient-generated CIK cells and tumor targets to consider the unique biology of each patient/tumor pairing. In primary tumor cell cultures, we visualized and immunophenotypically defined a putative mCSC subset using a novel gene transfer strategy that exploited their exclusive ability to activate the promoter of stemness gene Oct4.

Results: The CIK cells from 10 patients with metastatic melanoma were successfully expanded (median, 23-fold; range, 11-117). Primary tumor cell cultures established and characterized from the same patients were used as autologous targets. Patient-derived CIK cells efficiently killed autologous metastatic melanoma [up to 71% specific killing (n = 26)]. CIK cells were active in vivo against autologous melanoma, resulting in delayed tumor growth, increased necrotic areas, and lymphocyte infiltration at tumor sites. The metastatic melanoma cultures presented an average of 11.5% ± 2.5% putative mCSCs, which was assessed by Oct4 promoter activity and stemness marker expression (Oct4, ABCG2, ALDH, MITF). Expression was confirmed on mCSC target molecules recognized by CIK cells (MIC A/B; ULBPs). CIK tumor killing activity against mCSCs was intense (up to 71%, n = 4) and comparable with results reported against differentiated metastatic melanoma cells (P = 0.8).

Conclusions: For the first time, the intense killing activity of CIK cells against autologous metastatic melanoma, including mCSCs, has been shown. These findings move clinical investigation of a new immunotherapy for metastatic melanoma, including mCSCs, closer.
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http://dx.doi.org/10.1158/1078-0432.CCR-13-0061DOI Listing
August 2013

The Combination of Sorafenib and Everolimus Abrogates mTORC1 and mTORC2 upregulation in osteosarcoma preclinical models.

Clin Cancer Res 2013 Apr 22;19(8):2117-31. Epub 2013 Feb 22.

Sarcoma Group, Fondazione del Piemonte per l'Oncologia, Institute for Cancer Research and Treatment at Candiolo, Torino, Italy.

Purpose: The multikinase inhibitor sorafenib displays antitumor activity in preclinical models of osteosarcoma. However, in sorafenib-treated patients with metastatic-relapsed osteosarcoma, disease stabilization and tumor shrinkage were short-lived and drug resistance occurred. We explored the sorafenib treatment escape mechanisms to overcome their drawbacks.

Experimental Design: Immunoprecipitation, Western blotting, and immunohistochemistry were used to analyze the mTOR pathway [mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2)]. Cell viability, colony growth, and cell migration were evaluated in different osteosarcoma cell lines (MNNG-HOS, HOS, KHOS/NP, MG63, U-2OS, SJSA-1, and SAOS-2) after scalar dose treatment with sorafenib (10-0.625 μmol/L), rapamycin-analog everolimus (100-6.25 nmol/L), and combinations of the two. Cell cycle, reactive oxygen species (ROS) production, and apoptosis were assessed by flow cytometry. Nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice injected with MNNG-HOS cells were used to determine antitumor and antimetastatic effects. Angiogenesis and vascularization were evaluated in vitro by exploiting endothelial branching morphogenesis assays and in vivo in xenografted mice and chorioallantoic membranes.

Results: After sorafenib treatment, mTORC1 signaling was reduced (downstream target P-S6), whereas mTORC2 was increased (phospho-mTOR Ser2481) in MNNG-HOS xenografts compared with vehicle-treated mice. Combining sorafenib with everolimus resulted in complete abrogation of both mTORC1 [through ROS-mediated AMP-activated kinase (AMPK) activation] and mTORC2 (through complex disassembly). The sorafenib/everolimus combination yielded: (i) enhanced antiproliferative and proapoptotic effects, (ii) impaired tumor growth, (iii) potentiated antiangiogenesis, and (iv) reduced migratory and metastatic potential.

Conclusion: mTORC2 activation is an escape mechanism from sorafenib treatment. When sorafenib is combined with everolimus, its antitumor activity is increased by complete inhibition of the mTOR pathway in the preclinical setting.
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http://dx.doi.org/10.1158/1078-0432.CCR-12-2293DOI Listing
April 2013

Ex vivo allogeneic stimulation significantly improves expansion of cytokine-induced killer cells without increasing their alloreactivity across HLA barriers.

J Immunother 2012 Sep;35(7):579-86

Department of Oncological Sciences, Laboratory of Cell Therapy of Cancer, University of Torino Medical School, Institute for Cancer Research and Treatment, Candiolo, Torino, Italy.

Cytokine-induced killer cells (CIKs) are ex vivo expanded T-NK lymphocytes capable of HLA-unrestricted antitumor activity. CIKs are promising candidates for adoptive cancer immunotherapies; they can be generated and infused in autologous settings of cancer patients, or from donors, after allogeneic hematopoietic cell transplant. Ex vivo expansion rates of CIKs are greatly variable among patients, with consequent potential clinical limitations for "poor expanders." We compared the standard expansion protocol with a new one, which included the timed addition of irradiated allogeneic peripheral blood mononuclear cells. Our hypothesis is that allogeneic stimulation might provide CIK cells with a proliferative boost and simultaneously decrease their alloreactivity versus third parties, if HLA-mismatched from the allogeneic stimulators. Allo-stimulated CIKs (AS-CIK) reached significantly higher expansion rates compared with standard controls, regardless if generated form healthy donors (131- vs. 32-fold) or cancer patients (117- vs. 14-fold). The expansion of the CD3CD56 subset was 2243-fold for AS-CIKs compared with 362 for standard CIKs. AS-CIKs efficiently killed osteosarcoma targets in vitro, results were comparable with that of standard CIKs. Standard and AS-CIKs did not show differences in phenotype and telomere length. The alloreactivity of AS-CIKs against third party HLA-mismatched peripheral blood mononuclear cells was reduced compared with standard CIKs (37% vs. 23%). In conclusion, alloreactivity of CIK cells may be exploited enhancing their final ex vivo expansion. In clinical perspective these findings may facilitate the extension of CIK-based immunotherapy to larger numbers of patients and, translated into hematopoietic cell transplant settings, contribute to reduce the risk of graft versus host disease in the hypothesis of infusions across HLA barriers.
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http://dx.doi.org/10.1097/CJI.0b013e31826b1fd9DOI Listing
September 2012

Cytokine-induced killer (CIK) cells as feasible and effective adoptive immunotherapy for the treatment of solid tumors.

Expert Opin Biol Ther 2012 Jun 14;12(6):673-84. Epub 2012 Apr 14.

Department of Oncological Sciences, Laboratory of Cell Therapy of Cancer, University of Torino Medical School, Institute for Cancer Research and Treatment, Candiolo, Torino, Italy.

Introduction: Cytokine-induced killer (CIK) cells are heterogeneous ex vivo-expanded T lymphocytes with mixed T-NK phenotype and endowed with a wide MHC-unrestricted antitumor activity. CIK cells can be expanded from peripheral blood mononuclear cells (PBMC) cultured with the timed addition of IFN-γ, Ab anti-CD3 and IL2. A consistent subset of mature CIK cells presents a CD3(+)CD56(+) phenotype. The CD3(+)CD56(+) cellular subset is the main responsible for the tumor-killing activity, mostly mediated by the interaction of NKG2D receptor with MHC-unrestricted ligands (MIC A/B; ULBPs) on tumor cells.

Areas Covered: In the present work, we described the biologic characteristics of CIK cells, focusing on those aspects that may favor their clinical translation. We reviewed preclinical data and analyzed reports from clinical trials. A specific paragraph is dedicated to future research perspectives in the field.

Expert Opinion: CIK cells represent a realistic new option in the field of cancer immunotherapy. Crucial issues, favoring their clinical translation, are the easy availability of large amounts of expanded CIK cells and their MHC-unrestricted tumor killing, potentially effective against many tumor types. Intriguing future perspectives and open challenges are the investigation of synergisms with other immunotherapy approaches, targeted therapies or even conventional chemotherapy.
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http://dx.doi.org/10.1517/14712598.2012.675323DOI Listing
June 2012

Antitumor activity of Src inhibitor saracatinib (AZD-0530) in preclinical models of biliary tract carcinomas.

Mol Cancer Ther 2012 Jul 27;11(7):1528-38. Epub 2012 Mar 27.

Department of Medical Oncology, University of Turin Medical School, Turin, Italy.

Biliary tract carcinoma (BTC) has a poor prognosis due to limited treatment options. There is, therefore, an urgent need to identify new targets and to design innovative therapeutic approaches. Among potential candidate molecules, we evaluated the nonreceptor tyrosine kinase Src, observing promising antitumor effects of its small-molecule inhibitor saracatinib in BTC preclinical models. The presence of an active Src protein was investigated by immunohistochemistry in 19 surgical samples from patients with BTC. Upon saracatinib treatment, the phosphorylation of Src and of its downstream transducers was evaluated in the BTC cell lines TFK-1, EGI-1, HuH28, and TGBC1-TKB. The effect of saracatinib on proliferation and migration was analyzed in these same cell lines, and its antitumor activity was essayed in EGI-1 mouse xenografts. Saracatinib-modulated transcriptome was profiled in EGI-1 cells and in tumor samples of the xenograft model. Src was activated in about 80% of the human BTC samples. In cultured BTC cell lines, low-dose saracatinib counteracted the activation of Src and of its downstream effectors, increased the fraction of cells in G(0)-G(1) phase, and inhibited cell migration. At high concentrations (median dose from 2.26-6.99 μmol/L), saracatinib was also capable of inhibiting BTC cell proliferation. In vivo, saracatinib treatment resulted in delayed tumor growth, associated with an impaired vascular network. Here, we provide a demonstration that the targeted inhibition of Src kinase by saracatinib is of therapeutic benefit in preclinical models of BTC. We propose our results as a basis for the design of saracatinib-based clinical applications.
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http://dx.doi.org/10.1158/1535-7163.MCT-11-1020DOI Listing
July 2012

Transient proteasome inhibition as a strategy to enhance lentiviral transduction of hematopoietic CD34(+) cells and T lymphocytes: implications for the use of low viral doses and large-size vectors.

J Biotechnol 2011 Dec 10;156(3):218-26. Epub 2011 Sep 10.

Laboratory of Cell Therapy of Cancer, Department of Oncological Sciences, University of Torino Medical School, Institute for Cancer Research and Treatment, Provinciale 142, 10060 Candiolo, Torino, Italy.

The proteasome system restricts lentiviral transduction of stem cells. We exploited proteasome inhibition as a strategy to enhance transduction of both hematopoietic stem cells (HSC) and T lymphocytes with low dose or large-size lentiviral vectors (LV). HSC showed higher transduction efficiency if transiently exposed to proteasome inhibitor MG132 (41.8% vs 10.7%, p<0.0001). Treatment with MG132 (0.5 μM) retained its beneficial effect with 3 different LV of increasing size up to 10.9 Kb (p<0.01). We extended, for the first time, the application of proteasome inhibition to the transduction of T lymphocytes. A transient exposure to MG132 significantly improved lentiviral T-cell transduction. The mean percentage of transduced T cells progressively increased from 13.5% of untreated cells, to 21% (p=0.3), 30% (p=0.03) and 37% (p=0.01) of T lymphocytes that were pre-treated with MG132 at 0.1, 0.5 and 1 μM, respectively. MG132 did not affect viability or functionality of HSC or T cells, nor significantly increased the number of integrated vector copies. Transient proteasome inhibition appears as a new procedure to safely enhance lentiviral transduction of HSC and T lymphocytes with low viral doses. This approach could be useful in settings where the use of large size vectors may impair optimal viral production.
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http://dx.doi.org/10.1016/j.jbiotec.2011.09.001DOI Listing
December 2011

HER2-positive breast cancer cells resistant to trastuzumab and lapatinib lose reliance upon HER2 and are sensitive to the multitargeted kinase inhibitor sorafenib.

Breast Cancer Res Treat 2011 Nov 9;130(1):29-40. Epub 2010 Dec 9.

Department of Oncological Sciences, Institute for Cancer Research and Treatment (IRCC), University of Turin Medical School, Candiolo, TO, Italy.

Trastuzumab has changed the prognosis of HER2 positive breast cancers. Despite this progress, resistance to trastuzumab occurs in most patients. Newer anti-HER2 therapies, like the dual tyrosine-kinase inhibitor (TKI) lapatinib, show significant antitumor activity, indicating that HER2 can be still exploited as a target after trastuzumab failure. However, since a high proportion of patients fail to respond to these alternative strategies, it is possible that cell escape from HER2 targeting may rely on HER2 independent pathways. The knowledge of these pathways deserve to be exploited to develop new therapies. We characterized two human HER2 overexpressing breast cancer cell lines resistant to trastuzumab and lapatinib (T100 and JIMT-1) from a molecular and biological point of view. Indeed, we assessed both in vitro and in vivo the activity of the multitarget inhibitor sorafenib. In both cell lines, the previously proposed mechanisms did not explain resistance to HER2 inhibitors. Notably, silencing HER2 by shRNA did not affect the growth of our cells, suggesting loss of reliance upon HER2. Moreover, we identified alterations in two antiapoptotic proteins Mcl-1 and Survivin which are known to be targets of the multikinase inhibitor sorafenib. Moreover, sorafenib, strongly inhibited the in vitro growth of T100 and JIMT-1 cells, through the downregulation of both Mcl-1 and Survivin. Similar results were obtained in JIMT-1 xenografts subcutaneously injected in NOD SCID mice. We provide preclinical evidence that tumor cells resistant to trastuzumab and lapatinib may rely on HER2 independent pathways that can be efficiently inhibited by sorafenib.
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http://dx.doi.org/10.1007/s10549-010-1281-5DOI Listing
November 2011

Enhanced c-Met activity promotes G-CSF-induced mobilization of hematopoietic progenitor cells via ROS signaling.

Blood 2011 Jan 28;117(2):419-28. Epub 2010 Jun 28.

Department of Immunology, Weizmann Institute of Science, Rehovot, Israel.

Mechanisms governing stress-induced hematopoietic progenitor cell mobilization are not fully deciphered. We report that during granulocyte colony-stimulating factor-induced mobilization c-Met expression and signaling are up-regulated on immature bone marrow progenitors. Interestingly, stromal cell-derived factor 1/CXC chemokine receptor-4 signaling induced hepatocyte growth factor production and c-Met activation. We found that c-Met inhibition reduced mobilization of both immature progenitors and the more primitive Sca-1(+)/c-Kit(+)/Lin(-) cells and interfered with their enhanced chemotactic migration to stromal cell-derived factor 1. c-Met activation resulted in cellular accumulation of reactive oxygen species by mammalian target of rapamycin inhibition of Forkhead Box, subclass O3a. Blockage of mammalian target of rapamycin inhibition or reactive oxygen species signaling impaired c-Met-mediated mobilization. Our data show dynamic c-Met expression and function in the bone marrow and show that enhanced c-Met signaling is crucial to facilitate stress-induced mobilization of progenitor cells as part of host defense and repair mechanisms.
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http://dx.doi.org/10.1182/blood-2009-06-230359DOI Listing
January 2011