Publications by authors named "Hiroshi Kotani"

15 Publications

  • Page 1 of 1

CD28 Costimulatory Domain-Targeted Mutations Enhance Chimeric Antigen Receptor T-cell Function.

Cancer Immunol Res 2021 01 13;9(1):62-74. Epub 2020 Nov 13.

Department of Blood and Marrow Transplant and Cellular Immunotherapy, Division of Clinical Science, H. Lee Moffitt Cancer Center, Tampa, Florida.

An obstacle to the development of chimeric antigen receptor (CAR) T cells is the limited understanding of CAR T-cell biology and the mechanisms behind their antitumor activity. We and others have shown that CARs with a CD28 costimulatory domain drive high T-cell activation, which leads to exhaustion and shortened persistence. This work led us to hypothesize that by incorporating null mutations of CD28 subdomains (YMNM, PRRP, or PYAP), we could optimize CAR T-cell costimulation and enhance function. , we found that mice given CAR T cells with only a PYAP CD28 endodomain had a significant survival advantage, with 100% of mice alive after 62 days compared with 50% for mice with an unmutated endodomain. We observed that mutant CAR T cells remained more sensitive to antigen after antigen and PD-L1 stimulation, as demonstrated by increased cytokine production. The mutant CAR T cells also had a reduction of exhaustion-related transcription factors and genes such as , and Our results demonstrated that CAR T cells with a mutant CD28 endodomain have better survival and function. This work allows for the development of enhanced CAR T-cell therapies by optimizing CAR T-cell costimulation.
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http://dx.doi.org/10.1158/2326-6066.CIR-20-0253DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7864379PMC
January 2021

Tumor Microenvironment Composition and Severe Cytokine Release Syndrome (CRS) Influence Toxicity in Patients with Large B-Cell Lymphoma Treated with Axicabtagene Ciloleucel.

Clin Cancer Res 2020 09 15;26(18):4823-4831. Epub 2020 Jul 15.

Department of Blood and Marrow Transplantation and Cellular Immunotherapy, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida.

Purpose: One of the challenges of adoptive T-cell therapy is the development of immune-mediated toxicities including cytokine release syndrome (CRS) and neurotoxicity (NT). We aimed to identify factors that place patients at high risk of severe toxicity or treatment-related death in a cohort of 75 patients with large B-cell lymphoma treated with a standard of care CD19 targeted CAR T-cell product (axicabtagene ciloleucel).

Experimental Design: Serum cytokine and catecholamine levels were measured prior to lymphodepleting chemotherapy, on the day of CAR T infusion and daily thereafter while patients remained hospitalized. Tumor biopsies were taken within 1 month prior to CAR T infusion for evaluation of gene expression.

Results: We identified an association between pretreatment levels of IL6 and life-threatening CRS and NT. Because the risk of toxicity was related to pretreatment factors, we hypothesized that the tumor microenvironment (TME) may influence CAR T-cell toxicity. In pretreatment patient tumor biopsies, gene expression of myeloid markers was associated with higher toxicity.

Conclusions: These results suggest that a proinflammatory state and an unfavorable TME preemptively put patients at risk for toxicity after CAR T-cell therapy. Tailoring toxicity management strategies to patient risk may reduce morbidity and mortality.
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http://dx.doi.org/10.1158/1078-0432.CCR-20-1434DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7501265PMC
September 2020

Hidden disseminated extracutaneous AIDS-related Kaposi sarcoma.

IDCases 2020 10;19:e00716. Epub 2020 Feb 10.

Center for Infectious Diseases and Infection Control, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.

A 68-year-old man with past medical history of multiple cerebral infarctions presented to our hospital with subacute paresis. His vital signs on presentation were normal, and his physical examination, other than his neurological findings, was unremarkable. Neurological examinations suggested cerebellar ataxia. Laboratory testing confirmed positive for human immunodeficiency virus (HIV) infection. His CD4-positive lymphocyte count was 45/μL, and HIV-RNA was 2.3 × 10 copies/mL. Brain computed tomography (CT) scan revealed multiple mass lesions and brain magnetic resonance imaging (MRI) with fluid-attenuated inversion-recovery (FLAIR) revealed periventricular hyperintensities, which suggested multiple malignant lymphoma and HIV encephalopathy. His state of consciousness had gradually worsened. Eventually, he died one month after admission. The autopsy unexpectedly showed disseminated Kaposi's sarcoma (KS). KS lesions were found in the stomach, small intestine, liver, spleen, mesentery and lungs. KS was not observed on his skin. Gross findings revealed multiple nodular lesions in each organ, and hematoxylin and eosin staining showed proliferation of spindle cells with vascular proliferation. Immunostaining was positive both for endothelial marker (CD31 and von Willebrand factor) and lymphatic endothelial marker (D2-40), which were consistent with KS.KS is the most common tumor in AIDS patients. It is caused by the human herpes-virus 8 infection. It manifests an indolent clinical course and mostly involves cutaneous lesions over the lower limbs, trunk and oral cavity. In this case, autopsy revealed disseminated KS pathologically, which was unrecognized before his death. This case highlights the possible existence of disseminated KS even without its cutaneous findings.
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http://dx.doi.org/10.1016/j.idcr.2020.e00716DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7030992PMC
February 2020

IL-6 and G-CSF production resulting from lung cancer in an HIV patient.

IDCases 2020 9;19:e00693. Epub 2020 Jan 9.

Center for Infectious Diseases and Infection Control, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.

Increasing reports have noted an increased prevalence of lung cancer in human immunodeficiency virus (HIV)-positive patients with poor prognosis. A 51-year-old HIV-positive man was diagnosed with stage IV squamous cell lung cancer. He had high grade spike intermittent fever and persistent elevation of the white blood cell count as well as C-reactive protein (CRP) levels. Although we suspected opportunistic infections, we did not detect any infection. The autopsy showed positive immunostaining for Interleukin-6 (IL-6) in plasma cells of the stromal regions and G-CSF in tumor cells, which were considered responsible for his significant tumor fever, leukocytosis and high titers of CRP. This case report highlights the need to consider cytokine-producing tumor as a differential diagnosis of fever and high inflammatory status in HIV-positive cancer patients.
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http://dx.doi.org/10.1016/j.idcr.2020.e00693DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6970163PMC
January 2020

Variants That Affect Function of Calcium Channel TRPV6 Are Associated With Early-Onset Chronic Pancreatitis.

Gastroenterology 2020 05 10;158(6):1626-1641.e8. Epub 2020 Jan 10.

Department of Gastroenterology and Hepatology, Tokyo Medical University, Tokyo, Japan.

Background & Aims: Changes in pancreatic calcium levels affect secretion and might be involved in development of chronic pancreatitis (CP). We investigated the association of CP with the transient receptor potential cation channel subfamily V member 6 gene (TRPV6), which encodes a Ca-selective ion channel, in an international cohort of patients and in mice.

Methods: We performed whole-exome DNA sequencing from a patient with idiopathic CP and from his parents, who did not have CP. We validated our findings by sequencing DNA from 300 patients with CP (not associated with alcohol consumption) and 1070 persons from the general population in Japan (control individuals). In replication studies, we sequenced DNA from patients with early-onset CP (20 years or younger) not associated with alcohol consumption from France (n = 470) and Germany (n = 410). We expressed TRPV6 variants in HEK293 cells and measured their activity using Ca imaging assays. CP was induced by repeated injections of cerulein in TRPV6 mice.

Results: We identified the variants c.629C>T (p.A210V) and c.970G>A (p.D324N) in TRPV6 in the index patient. Variants that affected function of the TRPV6 product were found in 13 of 300 patients (4.3%) and 1 of 1070 control individuals (0.1%) from Japan (odds ratio [OR], 48.4; 95% confidence interval [CI], 6.3-371.7; P = 2.4 × 10). Twelve of 124 patients (9.7%) with early-onset CP had such variants. In the replication set from Europe, 18 patients with CP (2.0%) carried variants that affected the function of the TRPV6 product compared with 0 control individuals (P = 6.2 × 10). Variants that did not affect the function of the TRPV6 product (p.I223T and p.D324N) were overrepresented in Japanese patients vs control individuals (OR, 10.9; 95% CI, 4.5-25.9; P = 7.4 × 10 for p.I223T and P = .01 for p.D324N), whereas the p.L299Q was overrepresented in European patients vs control individuals (OR, 3.0; 95% CI, 1.9-4.8; P = 1.2 × 10). TRPV6 mice given cerulein developed more severe pancreatitis than control mice, as shown by increased levels of pancreatic enzymes, histologic alterations, and pancreatic fibrosis.

Conclusions: We found that patients with early-onset CP not associated with alcohol consumption carry variants in TRPV6 that affect the function of its product, perhaps by altering Ca balance in pancreatic cells. TRPV6 regulates Ca homeostasis and pancreatic inflammation.
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http://dx.doi.org/10.1053/j.gastro.2020.01.005DOI Listing
May 2020

Haemophagocytic lymphohistiocytosis has variable time to onset following CD19 chimeric antigen receptor T cell therapy.

Br J Haematol 2019 10 13;187(2):e35-e38. Epub 2019 Aug 13.

Department of Blood & Marrow Transplant and Cellular Immunotherapy, Moffitt Cancer Center, Tampa, FL, USA.

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http://dx.doi.org/10.1111/bjh.16155DOI Listing
October 2019

Pulmonary carcinosarcoma showing an obvious response to pazopanib: a case report.

BMC Pulm Med 2018 Dec 12;18(1):193. Epub 2018 Dec 12.

Division of Medical Oncology, Cancer Research Institute, Kanazawa University, 13-1, Takara-machi, Kanazawa, Ishikawa, 920-0934, Japan.

Background: Pulmonary carcinosarcoma (PCS) is a rare primary lung malignancy and has a poor prognosis among lung tumor histological subtypes. However, an appropriate treatment strategy has not been developed for unresectable PCS.

Case Presentation: A 65-year-old man who was diagnosed with PCS was treated by surgical removal of the primary lung lesion, followed by six cycles of adjuvant chemotherapy with cisplatin plus irinotecan. Following the chemotherapy, he experienced a relapse with brain metastasis, which induced the rapid onset of left leg paralysis. Radical surgical resection and stereotactic radiosurgery to the resection cavity were performed. However, meningeal dissemination and new lung metastases occurred after a year and half. To control these multiple metastatic lesions, the patient was treated with the multiple kinase inhibitor pazopanib. No change was observed in the meningeal dissemination, while the metastatic lung lesions were prominently reduced in size following treatment with pazopanib. Consequently, the patient showed a partial response to pazopanib treatment, although the dose of pazopanib was reduced by half as a result of thrombocytopenia.

Conclusion: This is the first report of metastatic PCS showing an evident therapeutic response to tumor-targeted therapy. We suggest that pazopanib may be a therapeutic option for patients with metastatic PCS.
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http://dx.doi.org/10.1186/s12890-018-0757-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6291996PMC
December 2018

4-1BB enhancement of CAR T function requires NF-κB and TRAFs.

JCI Insight 2018 09 20;3(18). Epub 2018 Sep 20.

Morsani College of Medicine, University of South Florida, Tampa, Florida, USA.

Chimeric antigen receptors (CARs) have an antigen-binding domain fused to transmembrane, costimulatory, and CD3ζ domains. Two CARs with regulatory approval include a CD28 or 4-1BB costimulatory domain. While both CARs achieve similar clinical outcomes, biologic differences have become apparent but not completely understood. Therefore, in this study we aimed to identify mechanistic differences between 4-1BB and CD28 costimulation that contribute to the biologic differences between the 2 CARs and could be exploited to enhance CAR T cell function. Using CD19-targeted CAR T cells with 4-1BB we determined that enhancement of T cell function is driven by NF-κB. Comparison to CAR T cells with CD28 also revealed that 4-1BB is associated with more antiapoptotic proteins and dependence on persistence for B cell killing. While TNF receptor-associated factor 2 (TRAF2) has been presupposed to be required for 4-1BB costimulation in CAR T cells, we determined that TRAF1 and TRAF3 are also critical. We observed that TRAFs impacted CAR T viability and proliferation, as well as cytotoxicity and/or cytokines, in part by regulating NF-κB. Our study demonstrates how 4-1BB costimulation in CAR T cells impacts antitumor eradication and clinical outcomes and has implications for enhanced CAR design.
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http://dx.doi.org/10.1172/jci.insight.121322DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6237232PMC
September 2018

Distinct dependencies on receptor tyrosine kinases in the regulation of MAPK signaling between BRAF V600E and non-V600E mutant lung cancers.

Oncogene 2018 03 19;37(13):1775-1787. Epub 2018 Jan 19.

Division of Medical Oncology, Cancer Research Institute, Kanazawa University, Ishikawa, Japan.

BRAF is one of the most frequently mutated genes across a number of different cancers, with the best-characterized mutation being V600E. Despite the successes of treating BRAF mutant V600E lung cancer with BRAF pathway inhibitors, treatment strategies targeting tumors with non-V600E mutations are yet to be established. We studied cellular signaling differences between lung cancers with different BRAF mutations and determined their sensitivities to BRAF pathway inhibitors. Here, we observed that MEK inhibition induced feedback activation of the receptor tyrosine kinase (RTK) EGFR, and in some cases the RTK FGFR, resulting in transient suppression of ERK phosphorylation in BRAF non-V600E, but not BRAF V600E, mutant cells. Furthermore, we found that both EGFR and FGFR activated the MEK/ERK pathway, despite the presence of BRAF non-V600E mutations with elevated kinase activity. Moreover, in BRAF non-V600E mutants with impaired kinase activities, EGFR had even greater control over the MEK/ERK pathway, essentially contributing completely to the tonic mitogen-activated protein kinase (MAPK) signal. Accordingly, the combination of MEK inhibitor with EGFR inhibitor was effective at shrinking tumors in mouse model of BRAF non-V600E mutant lung cancer. Furthermore, the results were recapitulated with a clinically relevant dual inhibitor of EGFR and RAF, BGB-283. Overall, although BRAF V600E mutant cells are sensitive to BRAF inhibition, non-V600E mutant cancer cells are reliant on RTKs for their MAPK activation and inhibiting both MEK and RTKs are necessary in these cancers. Our findings provide evidence of critical survival signals in BRAF non-V600E mutant cancers, which could pave the way for effective treatment of these cancers.
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http://dx.doi.org/10.1038/s41388-017-0035-9DOI Listing
March 2018

Resistance mediated by alternative receptor tyrosine kinases in FGFR1-amplified lung cancer.

Carcinogenesis 2017 10;38(11):1063-1072

Division of Medical Oncology, Cancer Research Institute, Kanazawa University, Ishikawa 920-0934, Japan.

Fibroblast growth factor receptor 1 (FGFR1) amplification has been identified in 10-20% of patients with squamous non-small-cell lung cancer. Preclinical models showed promising activity of specific FGFR inhibitors, but early clinical trials showed that only a small fraction of patients with FGFR1-amplified lung cancer responded to FGFR inhibitors. These unsatisfactory results were partly explained by heterogeneous amplicons around the 8p11 genomic region, leading to false-positive amplification results. Furthermore, discrepancies in the gene amplification and protein expression of FGFR1 were also reported. In this study, we identified the roles of alternative receptor tyrosine kinases (RTKs) in FGFR1-amplified lung cancer. These alternative RTKs dominantly activate phosphoinositide 3-kinase-AKT signaling and also mitigate sustained inhibition of mitogen-activated protein kinase signaling by FGFR inhibitors. The rebound activation of extracellular signal-regulated kinase phosphorylation was associated with sensitivity to the drugs. Combinatorial inhibition of alternative RTKs and FGFR1 was required to suppress both AKT and extracellular signal-regulated kinase phosphorylation and to induce key pro-apoptotic proteins BIM and p53 upregulated modulator of apoptosis (PUMA). Furthermore, even in FGFR inhibitor-sensitive NCI-H1581 lung cancer cells, MET-expressing clones were already detectable at a very low frequency before resistance induction. Selection of these pre-existing subclones resulted in FGFR inhibitor resistance because of the activation of AKT and extracellular signal-regulated kinase by MET signaling that was mediated by GRB2 associated binding protein 1 (GAB1). These results suggest that incomplete suppression of key survival signals led to intrinsic and acquired resistance to FGFR inhibitors. Our results may help explain the low clinical response rates to FGFR inhibitors in FGFR1-amplified lung cancer.
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http://dx.doi.org/10.1093/carcin/bgx091DOI Listing
October 2017

C-terminal splice variants of P/Q-type Ca channel Ca2.1 α subunits are differentially regulated by Rab3-interacting molecule proteins.

J Biol Chem 2017 06 4;292(22):9365-9381. Epub 2017 Apr 4.

From the Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, and

Voltage-dependent Ca channels (VDCCs) mediate neurotransmitter release controlled by presynaptic proteins such as the scaffolding proteins Rab3-interacting molecules (RIMs). RIMs confer sustained activity and anchoring of synaptic vesicles to the VDCCs. Multiple sites on the VDCC α and β subunits have been reported to mediate the RIMs-VDCC interaction, but their significance is unclear. Because alternative splicing of exons 44 and 47 in the P/Q-type VDCC α subunit Ca2.1 gene generates major variants of the Ca2.1 C-terminal region, known for associating with presynaptic proteins, we focused here on the protein regions encoded by these two exons. Co-immunoprecipitation experiments indicated that the C-terminal domain (CTD) encoded by Ca2.1 exons 40-47 interacts with the α-RIMs, RIM1α and RIM2α, and this interaction was abolished by alternative splicing that deletes the protein regions encoded by exons 44 and 47. Electrophysiological characterization of VDCC currents revealed that the suppressive effect of RIM2α on voltage-dependent inactivation (VDI) was stronger than that of RIM1α for the Ca2.1 variant containing the region encoded by exons 44 and 47. Importantly, in the Ca2.1 variant in which exons 44 and 47 were deleted, strong RIM2α-mediated VDI suppression was attenuated to a level comparable with that of RIM1α-mediated VDI suppression, which was unaffected by the exclusion of exons 44 and 47. Studies of deletion mutants of the exon 47 region identified 17 amino acid residues on the C-terminal side of a polyglutamine stretch as being essential for the potentiated VDI suppression characteristic of RIM2α. These results suggest that the interactions of the Ca2.1 CTD with RIMs enable Ca2.1 proteins to distinguish α-RIM isoforms in VDI suppression of P/Q-type VDCC currents.
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http://dx.doi.org/10.1074/jbc.M117.778829DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5454116PMC
June 2017

Possible involvement of distinct phylogenetic clusters of HIV-1 variants in the discrepancies between coreceptor tropism predictions based on viral RNA and proviral DNA.

J Pharm Health Care Sci 2016 9;2:31. Epub 2016 Nov 9.

Department of Microbiology and Immunology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582 Japan.

Background: The coreceptor tropism testing should be conducted prior to commencing a regimen containing a CCR5 antagonist for treatment of HIV-1 infection. For aviremic patients on long antiretroviral therapy, proviral DNA is often used instead of viral RNA in genotypic tropism testing. However, the tropism predictions from RNA and DNA are sometimes different. We examined the cause of the discrepancies between HIV-1 tropism predictions based on viral RNA and proviral DNA.

Methods: The nucleotide sequence of the C2V3C3 region was determined using pair samples of plasma RNA and peripheral blood mononuclear cell DNA from 50 HIV-1 subtype B-infected individuals using population-based sequencing. The samples with discrepant tropism assessments between RNA and DNA were further analyzed using deep sequencing, followed by phylogenetic analysis. The tropism was assessed using the algorithm geno2pheno with a false-positive rate cutoff of 10 %.

Results: In population-based sequencing, five of 50 subjects showed discrepant tropism predictions between their RNA and DNA samples: four exhibited R5 tropism in RNA and X4 tropism in DNA, while one exhibited the opposite pattern. In the deep sequencing and phylogenetic analysis, three subjects had single clusters comprising of RNA- and DNA-derived sequences that were a mixture of R5 and X4 sequences. The other two subjects had two and three distinct phylogenetic clusters of sequences, respectively, each of which was dominated by R5 or X4 sequences; sequences of the R5-dominated cluster were mostly found in RNA, while sequences of the X4-dominated cluster were mostly in DNA.

Conclusions: Some of HIV-1 tropism discrepancies between viral RNA and proviral DNA seem to be caused by phylogenetically distinct clusters which resides in plasma and cells in different frequencies. Our findings suggest that the tropism testing using PBMC DNA or deep sequencing may be required when the viral load is not suppressed or rebounds in the course of a CCR5 antagonist-containing regimen.
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http://dx.doi.org/10.1186/s40780-016-0065-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5103409PMC
November 2016

Epithelial-to-Mesenchymal Transition Defines Feedback Activation of Receptor Tyrosine Kinase Signaling Induced by MEK Inhibition in KRAS-Mutant Lung Cancer.

Cancer Discov 2016 07 6;6(7):754-69. Epub 2016 May 6.

Division of Medical Oncology, Cancer Research Institute, Kanazawa University, Ishikawa, Japan.

Unlabelled: KRAS is frequently mutated in lung cancer. Whereas MAPK is a well-known effector pathway of KRAS, blocking this pathway with clinically available MAPK inhibitors is relatively ineffective. Here, we report that epithelial-to-mesenchymal transition rewires the expression of receptor tyrosine kinases, leading to differential feedback activation of the MAPK pathway following MEK inhibition. In epithelial-like KRAS-mutant lung cancers, this feedback was attributed to ERBB3-mediated activation of MEK and AKT. In contrast, in mesenchymal-like KRAS-mutant lung cancers, FGFR1 was dominantly expressed but suppressed by the negative regulator Sprouty proteins; MEK inhibition led to repression of SPRY4 and subsequent FGFR1-mediated reactivation of MEK and AKT. Therapeutically, the combination of a MEK inhibitor (MEKi) and an FGFR inhibitor (FGFRi) induced cell death in vitro and tumor regressions in vivo These data establish the rationale and a therapeutic approach to treat mesenchymal-like KRAS-mutant lung cancers effectively with clinically available FGFR1 and MAPK inhibitors.

Significance: Adaptive resistance to MEKi is driven by receptor tyrosine kinases specific to the differentiation state of the KRAS-mutant non-small cell lung cancer (NSCLC). In mesenchymal-like KRAS-mutant NSCLC, FGFR1 is highly expressed, and MEK inhibition relieves feedback suppression of FGFR1, resulting in reactivation of ERK; suppression of ERK by MEKi/FGFRi combination results in tumor shrinkage. Cancer Discov; 6(7); 754-69. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 681.
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http://dx.doi.org/10.1158/2159-8290.CD-15-1377DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4957999PMC
July 2016

Recurrence of renal cell carcinoma diagnosed using contralateral adrenal biopsy with endoscopic ultrasound-guided fine-needle aspiration.

Mol Clin Oncol 2016 Apr 25;4(4):537-540. Epub 2016 Jan 25.

Division of Medical Oncology, Cancer Research Institute, Kanazawa University, Kanazawa, Ishikawa 920-0934, Japan.

A 76-year-old female in whom a renal cell carcinoma (RCC) lesion was resected 19 years previously presented to our hospital with cognitive dysfunction. Magnetic resonance imaging and computed tomography revealed nodules in the brain, lung, adrenal gland and a pelvic osteolytic lesion. To identify the primary cancer site, the present study performed endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) of the left adrenal lesion. Consequently, the pathological findings of the tissue obtained by EUS-FNA were similar to those of the previous nephrectomy specimen, revealing that the adrenal lesion was the recurrence of RCC. The majority of the metastatic lesions in the patient were reduced in size by the multiple kinase inhibitor, pazopanib. Contralateral adrenal metastasis of RCC is rare and the use of EUS-FNA in the diagnosis of adrenal lesions remains to be elucidated. This is a rare case of adrenal lesion, diagnosed by EUS-FNA. Therefore, EUS-FNA is considered to be a useful diagnostic modality of adrenal metastases from unidentified primary tumor types.
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http://dx.doi.org/10.3892/mco.2016.739DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4812346PMC
April 2016

PI3K regulates MEK/ERK signaling in breast cancer via the Rac-GEF, P-Rex1.

Proc Natl Acad Sci U S A 2013 Dec 10;110(52):21124-9. Epub 2013 Dec 10.

Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, MA 02129.

The PI3K pathway is genetically altered in excess of 70% of breast cancers, largely through PIK3CA mutation and HER2 amplification. Preclinical studies have suggested that these subsets of breast cancers are particularly sensitive to PI3K inhibitors; however, the reasons for this heightened sensitivity are mainly unknown. We investigated the signaling effects of PI3K inhibition in PIK3CA mutant and HER2 amplified breast cancers using PI3K inhibitors currently in clinical trials. Unexpectedly, we found that in PIK3CA mutant and HER2 amplified breast cancers sensitive to PI3K inhibitors, PI3K inhibition led to a rapid suppression of Rac1/p21-activated kinase (PAK)/protein kinase C-RAF (C-RAF)/ protein kinase MEK (MEK)/ERK signaling that did not involve RAS. Furthermore, PI3K inhibition led to an ERK-dependent up-regulation of the proapoptotic protein, BIM, followed by induction of apoptosis. Expression of a constitutively active form of Rac1 in these breast cancer models blocked PI3Ki-induced down-regulation of ERK phosphorylation, apoptosis, and mitigated PI3K inhibitor sensitivity in vivo. In contrast, protein kinase AKT inhibitors failed to block MEK/ERK signaling, did not up-regulate BIM, and failed to induce apoptosis. Finally, we identified phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger 1 (P-Rex1) as the PI(3,4,5)P3-dependent guanine exchange factor for Rac1 responsible for regulation of the Rac1/C-RAF/MEK/ERK pathway in these cells. The expression level of P-Rex1 correlates with sensitivity to PI3K inhibitors in these breast cancer cell lines. Thus, PI3K inhibitors have enhanced activity in PIK3CA mutant and HER2 amplified breast cancers in which PI3K inhibition down-regulates both the AKT and Rac1/ERK pathways. In addition, P-Rex1 may serve as a biomarker to predict response to single-agent PI3K inhibitors within this subset of breast cancers.
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http://dx.doi.org/10.1073/pnas.1314124110DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3876254PMC
December 2013