Publications by authors named "Olga Dakhova"

24 Publications

  • Page 1 of 1

Anti-GD2 CAR-NKT cells in patients with relapsed or refractory neuroblastoma: an interim analysis.

Nat Med 2020 11 12;26(11):1686-1690. Epub 2020 Oct 12.

Department of Pediatrics, Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, USA.

Vα24-invariant natural killer T (NKT) cells have shown potent anti-tumor properties in murine tumor models and have been linked to favorable outcomes in patients with cancer. However, low numbers of these cells in humans have hindered their clinical applications. Here we report interim results from all three patients enrolled on dose level 1 in a phase 1 dose-escalation trial of autologous NKT cells engineered to co-express a GD2-specific chimeric antigen receptor (CAR) with interleukin-15 in children with relapsed or resistant neuroblastoma (NCT03294954). Primary and secondary objectives were to assess safety and anti-tumor responses, respectively, with immune response evaluation as an additional objective. We ex vivo expanded highly pure NKT cells (mean ± s.d., 94.7 ± 3.8%) and treated patients with 3 × 10 CAR-NKT cells per square meter of body surface area after lymphodepleting conditioning with cyclophosphamide/fludarabine (Cy/Flu). Cy/Flu conditioning was the probable cause for grade 3-4 hematologic adverse events, as they occurred before CAR-NKT cell infusion, and no dose-limiting toxicities were observed. CAR-NKT cells expanded in vivo, localized to tumors and, in one patient, induced an objective response with regression of bone metastatic lesions. These initial results suggest that CAR-NKT cells can be expanded to clinical scale and safely applied to treat patients with cancer.
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http://dx.doi.org/10.1038/s41591-020-1074-2DOI Listing
November 2020

Tumor response and endogenous immune reactivity after administration of HER2 CAR T cells in a child with metastatic rhabdomyosarcoma.

Nat Commun 2020 07 15;11(1):3549. Epub 2020 Jul 15.

Texas Children's Cancer and Hematology Centers, Texas Children's Hospital, Baylor College of Medicine, Houston, TX, USA.

Refractory metastatic rhabdomyosarcoma is largely incurable. Here we analyze the response of a child with refractory bone marrow metastatic rhabdomyosarcoma to autologous HER2 CAR T cells. Three cycles of HER2 CAR T cells given after lymphodepleting chemotherapy induces remission which is consolidated with four more CAR T-cell infusions without lymphodepletion. Longitudinal immune-monitoring reveals remodeling of the T-cell receptor repertoire with immunodominant clones and serum autoantibodies reactive to oncogenic signaling pathway proteins. The disease relapses in the bone marrow at six months off-therapy. A second remission is achieved after one cycle of lymphodepletion and HER2 CAR T cells. Response consolidation with additional CAR T-cell infusions includes pembrolizumab to improve their efficacy. The patient described here is a participant in an ongoing phase I trial (NCT00902044; active, not recruiting), and is 20 months off T-cell infusions with no detectable disease at the time of this report.
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http://dx.doi.org/10.1038/s41467-020-17175-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7363864PMC
July 2020

T-Cell Receptor Stimulation Enhances the Expansion and Function of CD19 Chimeric Antigen Receptor-Expressing T Cells.

Clin Cancer Res 2019 12 26;25(24):7340-7350. Epub 2019 Sep 26.

Center for Cell and Gene Therapy, Baylor College of Medicine, Houston Methodist Hospital, Texas Children's Hospital, Houston, Texas.

Purpose: Current protocols for CD19 chimeric antigen receptor-expressing T cells (CD19.CAR-T cells) require recipients to tolerate preinfusion cytoreductive chemotherapy, and the presence of sufficient target antigen on normal or malignant B cells.

Patients And Methods: We investigated whether additional stimulation of CD19.CAR-T cells through their native receptors can substitute for cytoreductive chemotherapy, inducing expansion and functional persistence of CD19.CAR-T even in patients in remission of B-cell acute lymphocytic leukemia. We infused a low dose of CD19.CAR-modified virus-specific T cells (CD19.CAR-VST) without prior cytoreductive chemotherapy into 8 patients after allogeneic stem cell transplant.

Results: Absent virus reactivation, we saw no CD19.CAR-VST expansion. In contrast, in patients with viral reactivation, up to 30,000-fold expansion of CD19.CAR-VSTs was observed, with depletion of CD19 B cells. Five patients remain in remission at 42-60+ months.

Conclusions: Dual T-cell receptor and CAR stimulation can thus potentiate effector cell expansion and CAR-target cell killing, even when infusing low numbers of effector cells without cytoreduction.
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http://dx.doi.org/10.1158/1078-0432.CCR-18-3199DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7062259PMC
December 2019

In Vivo Fate and Activity of Second- versus Third-Generation CD19-Specific CAR-T Cells in B Cell Non-Hodgkin's Lymphomas.

Mol Ther 2018 12 13;26(12):2727-2737. Epub 2018 Sep 13.

Center for Cell and Gene Therapy, Baylor College of Medicine, Houston Methodist Hospital and Texas Children's Hospital, Houston, TX 77030, USA; Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA. Electronic address:

Second-generation (2G) chimeric antigen receptors (CARs) targeting CD19 are highly active against B cell malignancies, but it is unknown whether any of the costimulatory domains incorporated in the CAR have superior activity to others. Because CD28 and 4-1BB signaling activate different pathways, combining them in a single third-generation (3G) CAR may overcome the limitations of each individual costimulatory domain. We designed a clinical trial in which two autologous CD19-specific CAR-transduced T cell products (CD19.CARTs), 2G (with CD28 only) and 3G (CD28 and 4-1BB), were infused simultaneously in 16 patients with relapsed or refractory non-Hodgkin's lymphoma. 3G CD19.CARTs had superior expansion and longer persistence than 2G CD19.CARTs. This difference was most striking in the five patients with low disease burden and few circulating normal B cells, in whom 2G CD19.CARTs had limited expansion and persistence and correspondingly reduced area under the curve. Of the 11 patients with measurable disease, three achieved complete responses and three had partial responses. Cytokine release syndrome occurred in six patients but was mild, and no patient required anti-IL-6 therapy. Hence, 3G CD19.CARTs combining 4-1BB with CD28 produce superior CART expansion and may be of particular value when treating low disease burden in patients whose normal B cells are depleted by prior therapy.
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http://dx.doi.org/10.1016/j.ymthe.2018.09.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6277484PMC
December 2018

Tumor-Specific T-Cells Engineered to Overcome Tumor Immune Evasion Induce Clinical Responses in Patients With Relapsed Hodgkin Lymphoma.

J Clin Oncol 2018 04 9;36(11):1128-1139. Epub 2018 Jan 9.

Catherine M. Bollard, Tamara Tripic, Gianpietro Dotti, Stephen Gottschalk, Vicky Torrano, Olga Dakhova, George Carrum, Carlos A. Ramos, Adrian P. Gee, Malcolm K. Brenner, Helen E. Heslop, and Cliona M. Rooney, Houston Methodist Hospital, and Texas Children's Hospital; Catherine M. Bollard, Gianpietro Dotti, Stephen Gottschalk, George Carrum, Carlos A. Ramos, Hao Liu, Meng-Fen Wu, Andrea N. Marcogliese, Adrian P. Gee, Malcolm K. Brenner, Helen E. Heslop, and Cliona M. Rooney, Baylor College of Medicine, Houston, TX; Catherine M. Bollard, Conrad Russell Cruz, and Cecilia Barese, Children's National Health System, Washington, DC; Youli Zu and Daniel Y. Lee, Weill Medical College of Cornell University; and Owen O'Connor, Columbia University College of Physicians and Surgeons, The New York Presbyterian Hospital, New York, NY.

Purpose Transforming growth factor-β (TGF-β) production in the tumor microenvironment is a potent and ubiquitous tumor immune evasion mechanism that inhibits the expansion and function of tumor-directed responses; therefore, we conducted a clinical study to discover the effects of the forced expression of a dominant-negative TGF-β receptor type 2 (DNRII) on the safety, survival, and activity of infused tumor-directed T cells. Materials and Methods In a dose escalation study, eight patients with Epstein Barr virus-positive Hodgkin lymphoma received two to 12 doses of between 2 × 10 and 1.5 × 10 cells/m of DNRII-expressing T cells with specificity for the Epstein Barr virus-derived tumor antigens, latent membrane protein (LMP)-1 and LMP-2 (DNRII-LSTs). Lymphodepleting chemotherapy was not used before infusion. Results DNRII-LSTs were resistant to otherwise inhibitory concentrations of TGF-β in vitro and retained their tumor antigen-specific activity. After infusion, the signal from transgenic T cells in peripheral blood increased up to 100-fold as measured by quantitative polymerase chain reaction for the transgene, with a corresponding increase in the frequency of functional LMP-specific T cells. Expansion was not associated with any acute or long-term toxicity. DNRII-LSTs persisted for up to ≥ 4 years. Four of the seven evaluable patients with active disease achieved clinical responses that were complete and ongoing in two patients at > 4 years, including in one patient who achieved only a partial response to unmodified tumor-directed T cells. Conclusion TGF-β-resistant tumor-specific T cells safely expand and persist in patients with Hodgkin lymphoma without lymphodepleting chemotherapy before infusion. DNRII-LSTs can induce complete responses even in patients with resistant disease. Expression of DNRII may be useful for the many other tumors that exploit this potent immune evasion mechanism.
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http://dx.doi.org/10.1200/JCO.2017.74.3179DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5891126PMC
April 2018

c-MPL provides tumor-targeted T-cell receptor-transgenic T cells with costimulation and cytokine signals.

Blood 2017 12 27;130(25):2739-2749. Epub 2017 Oct 27.

Center for Cell and Gene Therapy, Baylor College of Medicine, Houston Methodist Hospital and Texas Children's Hospital, Houston, TX; and.

Adoptively transferred T-cell receptor (TCR)-engineered T cells depend on host-derived costimulation and cytokine signals for their full and sustained activation. However, in patients with cancer, both signals are frequently impaired. Hence, we developed a novel strategy that combines both essential signals in 1 transgene by expressing the nonlymphoid hematopoietic growth factor receptor c-MPL (myeloproliferative leukemia), the receptor for thrombopoietin (TPO), in T cells. c-MPL signaling activates pathways shared with conventional costimulatory and cytokine receptor signaling. Thus, we hypothesized that host-derived TPO, present in the tumor microenvironment, or pharmacological c-MPL agonists approved by the US Food and Drug Administration could deliver both signals to c-MPL-engineered TCR-transgenic T cells. We found that c-MPL polyclonal T cells expand and proliferate in response to TPO, and persist longer after adoptive transfer in immunodeficient human TPO-transgenic mice. In TCR-transgenic T cells, c-MPL activation enhances antitumor function, T-cell expansion, and cytokine production and preserves a central memory phenotype. c-MPL signaling also enables sequential tumor cell killing, enhances the formation of effective immune synapses, and improves antileukemic activity in vivo in a leukemia xenograft model. We identify the type 1 interferon pathway as a molecular mechanism by which c-MPL mediates immune stimulation in T cells. In conclusion, we present a novel immunotherapeutic strategy using c-MPL-enhanced transgenic T cells responding to either endogenously produced TPO (a microenvironment factor in hematologic malignancies) or c-MPL-targeted pharmacological agents.
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http://dx.doi.org/10.1182/blood-2017-02-769463DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5746163PMC
December 2017

Tonic 4-1BB Costimulation in Chimeric Antigen Receptors Impedes T Cell Survival and Is Vector-Dependent.

Cell Rep 2017 Oct;21(1):17-26

Center for Cell and Gene Therapy, Baylor College of Medicine, Texas Children's Hospital, Houston Methodist Hospital, Houston, TX 77030, USA; Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030, USA. Electronic address:

Antigen-independent tonic signaling by chimeric antigen receptors (CARs) can increase differentiation and exhaustion of T cells, limiting their potency. Incorporating 4-1BB costimulation in CARs may enable T cells to resist this functional exhaustion; however, the potential ramifications of tonic 4-1BB signaling in CAR T cells remain unclear. Here, we found that tonic CAR-derived 4-1BB signaling can produce toxicity in T cells via continuous TRAF2-dependent activation of the nuclear factor κB (NF-κB) pathway and augmented FAS-dependent cell death. This mechanism was amplified in a non-self-inactivating gammaretroviral vector through positive feedback on the long terminal repeat (LTR) promoter, further enhancing CAR expression and tonic signaling. Attenuating CAR expression by substitution with a self-inactivating lentiviral vector minimized tonic signaling and improved T cell expansion and anti-tumor function. These studies illuminate the interaction between tonic CAR signaling and the chosen expression platform and identify inhibitory properties of the 4-1BB costimulatory domain that have direct implications for rational CAR design.
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http://dx.doi.org/10.1016/j.celrep.2017.09.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5645034PMC
October 2017

Clinical and immunological responses after CD30-specific chimeric antigen receptor-redirected lymphocytes.

J Clin Invest 2017 Sep 14;127(9):3462-3471. Epub 2017 Aug 14.

Center for Cell and Gene Therapy, Baylor College of Medicine, Houston Methodist Hospital and Texas Children's Hospital, Houston, Texas, USA.

Background: Targeting CD30 with monoclonal antibodies in Hodgkin lymphoma (HL) and anaplastic large cell lymphoma (ALCL) has had profound clinical success. However, adverse events, mainly mediated by the toxin component of the conjugated antibodies, cause treatment discontinuation in many patients. Targeting CD30 with T cells expressing a CD30-specific chimeric antigen receptor (CAR) may reduce the side effects and augment antitumor activity.

Methods: We conducted a phase I dose escalation study in which 9 patients with relapsed/refractory HL or ALCL were infused with autologous T cells that were gene-modified with a retroviral vector to express the CD30-specific CAR (CD30.CAR-Ts) encoding the CD28 costimulatory endodomain. Three dose levels, from 0.2 × 108 to 2 × 108 CD30.CAR-Ts/m2, were infused without a conditioning regimen. All other therapy for malignancy was discontinued at least 4 weeks before CD30.CAR-T infusion. Seven patients had previously experienced disease progression while being treated with brentuximab.

Results: No toxicities attributable to CD30.CAR-Ts were observed. Of 7 patients with relapsed HL, 1 entered complete response (CR) lasting more than 2.5 years after the second infusion of CD30.CAR-Ts, 1 remained in continued CR for almost 2 years, and 3 had transient stable disease. Of 2 patients with ALCL, 1 had a CR that persisted 9 months after the fourth infusion of CD30.CAR-Ts. CD30.CAR-T expansion in peripheral blood peaked 1 week after infusion, and CD30.CAR-Ts remained detectable for over 6 weeks. Although CD30 may also be expressed by normal activated T cells, no patients developed impaired virus-specific immunity.

Conclusion: CD30.CAR-Ts are safe and can lead to clinical responses in patients with HL and ALCL, indicating that further assessment of this therapy is warranted.

Trial Registration: ClinicalTrials.gov NCT01316146.

Funding: National Cancer Institute (3P50CA126752, R01CA131027 and P30CA125123), National Heart, Lung, and Blood Institute (R01HL114564), and Leukemia and Lymphoma Society (LLSTR 6227-08).
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http://dx.doi.org/10.1172/JCI94306DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5669573PMC
September 2017

CAR T Cells Administered in Combination with Lymphodepletion and PD-1 Inhibition to Patients with Neuroblastoma.

Mol Ther 2017 09 9;25(9):2214-2224. Epub 2017 Jun 9.

Center for Cell and Gene Therapy, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, TX 77030, USA.

Targeting disialoganglioside (GD2) on neuroblastoma (NB) with T cells expressing a first-generation chimeric antigen receptor (CAR) was safe, but the cells had poor expansion and long-term persistence. We developed a third-generation GD2-CAR (GD2-CAR3) and hypothesized that GD2-CAR3 T cells (CARTs) would be safe and effective. This phase 1 study enrolled relapsed or refractory NB patients in three cohorts. Cohort 1 received CART alone, cohort 2 received CARTs plus cyclophosphamide and fludarabine (Cy/Flu), and cohort 3 was treated with CARTs, Cy/Flu, and a programmed death-1 (PD-1) inhibitor. Eleven patients were treated with CARTs. The infusions were safe, and no dose-limiting toxicities occurred. CARTs were detectable in cohort 1, but the lymphodepletion induced by Cy/Flu increased circulating levels of the homeostatic cytokine interleukin (IL)-15 (p = 0.003) and increased CART expansion by up to 3 logs (p = 0.03). PD-1 inhibition did not further enhance expansion or persistence. Antitumor responses at 6 weeks were modest. We observed a striking expansion of CD45/CD33/CD11b/CD163 myeloid cells (change from baseline, p = 0.0126) in all patients, which may have contributed to the modest early antitumor responses; the effect of these cells merits further study. Thus, CARTs are safe, and Cy/Flu can further increase their expansion.
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http://dx.doi.org/10.1016/j.ymthe.2017.05.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5589058PMC
September 2017

Clinical responses with T lymphocytes targeting malignancy-associated κ light chains.

J Clin Invest 2016 07 6;126(7):2588-96. Epub 2016 Jun 6.

Background: Treatment of B cell malignancies with adoptive transfer of T cells with a CD19-specific chimeric antigen receptor (CAR) shows remarkable clinical efficacy. However, long-term persistence of T cells targeting CD19, a pan-B cell marker, also depletes normal B cells and causes severe hypogammaglobulinemia. Here, we developed a strategy to target B cell malignancies more selectively by taking advantage of B cell light Ig chain restriction. We generated a CAR that is specific for the κ light chain (κ.CAR) and therefore recognizes κ-restricted cells and spares the normal B cells expressing the nontargeted λ light chain, thus potentially minimizing humoral immunity impairment.

Methods: We conducted a phase 1 clinical trial and treated 16 patients with relapsed or refractory κ+ non-Hodgkin lymphoma/chronic lymphocytic leukemia (NHL/CLL) or multiple myeloma (MM) with autologous T cells genetically modified to express κ.CAR (κ.CARTs). Other treatments were discontinued in 11 of the 16 patients at least 4 weeks prior to T cell infusion. Six patients without lymphopenia received 12.5 mg/kg cyclophosphamide 4 days before κ.CART infusion (0.2 × 108 to 2 × 108 κ.CARTs/m2). No other lymphodepletion was used.

Results: κ.CART expansion peaked 1-2 weeks after infusion, and cells remained detectable for more than 6 weeks. Of 9 patients with relapsed NHL or CLL, 2 entered complete remission after 2 and 3 infusions of κ.CARTs, and 1 had a partial response. Of 7 patients with MM, 4 had stable disease lasting 2-17 months. No toxicities attributable to κ.CARTs were observed.

Conclusion: κ.CART infusion is feasible and safe and can lead to complete clinical responses.

Trial Registration: ClinicalTrials.gov NCT00881920.

Funding: National Cancer Institute (NCI) grants 3P50CA126752 and 5P30CA125123 and Leukemia and Lymphoma Society (LLS) Specialized Centers of Research (SCOR) grant 7018.
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http://dx.doi.org/10.1172/JCI86000DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4922690PMC
July 2016

Cells Comprising the Prostate Cancer Microenvironment Lack Recurrent Clonal Somatic Genomic Aberrations.

Mol Cancer Res 2016 Apr 11;14(4):374-84. Epub 2016 Jan 11.

Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington. Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington. Division of Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, Washington. Department of Pathology, University of Washington, Seattle, Washington. Department of Urology, University of Washington, Seattle, Washington. Department of Medicine, University of Washington, Seattle, Washington.

Unlabelled: Prostate cancer-associated stroma (CAS) plays an active role in malignant transformation, tumor progression, and metastasis. Molecular analyses of CAS have demonstrated significant changes in gene expression; however, conflicting evidence exists on whether genomic alterations in benign cells comprising the tumor microenvironment (TME) underlie gene expression changes and oncogenic phenotypes. This study evaluates the nuclear and mitochondrial DNA integrity of prostate carcinoma cells, CAS, matched benign epithelium and benign epithelium-associated stroma by whole-genome copy-number analyses, targeted sequencing of TP53, and FISH. Array comparative genomic hybridization (aCGH) of CAS revealed a copy-neutral diploid genome with only rare and small somatic copy-number aberrations (SCNA). In contrast, several expected recurrent SCNAs were evident in the adjacent prostate carcinoma cells, including gains at 3q, 7p, and 8q, and losses at 8p and 10q. No somatic TP53 mutations were observed in CAS. Mitochondrial DNA (mtDNA) extracted from carcinoma cells and stroma identified 23 somatic mtDNA mutations in neoplastic epithelial cells, but only one mutation in stroma. Finally, genomic analyses identified no SCNAs, LOH, or copy-neutral LOH in cultured cancer-associated fibroblasts, which are known to promote prostate cancer progression in vivo

Implications: The gene expression changes observed in prostate cancer-adjacent stroma and the attendant contribution of the stroma to the development and progression of prostate cancer are not due to frequent or recurrent genomic alterations in the TME.
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http://dx.doi.org/10.1158/1541-7786.MCR-15-0330DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5582956PMC
April 2016

Serial Activation of the Inducible Caspase 9 Safety Switch After Human Stem Cell Transplantation.

Mol Ther 2016 Apr 28;24(4):823-31. Epub 2015 Dec 28.

Center for Cell and Gene Therapy, Baylor College of Medicine, Texas Children's Hospital and Houston Methodist Hospital, Houston, Texas, USA.

Activation of the inducible caspase 9 (iC9) safety gene by a dimerizing drug (chemical inducer of dimerization (CID) AP1903) effectively resolves the symptoms and signs of graft-versus-host disease (GvHD) in haploidentical stem cell transplant (HSCT) recipients. However, after CID treatment, 1% of iC9-T cells remain and can regrow over time; although these resurgent T cells do not cause recurrent GvHD, it remains unclear whether repeat CID treatments are a safe and feasible way to further deplete residual gene-modified T cells should any other adverse effects associated with them occur. Here, we report a patient who received an infusion of haploidentical iC9-T cells after HSCT and subsequently received three treatments with AP1903. There was a mild (grade 2) and transient pancytopenia following each AP1903 administration but no non-hematological toxicity. Ninety five percent of circulating iC9-T cells (CD3(+)CD19(+)) were eliminated after the first AP1903 treatment. Three months later, the residual cells had expanded more than eightfold and had a lower level of iC9 expression. Each repeated AP1903 administration eliminated a diminishing percentage of the residual repopulating cells, but elimination could be enhanced by T-cell activation. These data support the safety and efficiency of repeated CID treatments for persistent or recurring toxicity from T-cell therapies.
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http://dx.doi.org/10.1038/mt.2015.234DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4886936PMC
April 2016

Clonal Dynamics In Vivo of Virus Integration Sites of T Cells Expressing a Safety Switch.

Mol Ther 2016 04 7;24(4):736-45. Epub 2015 Dec 7.

Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, Texas, USA.

Safety switches are becoming relevant for the clinical translation of T-cell-based immunotherapies. In patients receiving an allogeneic hematopoietic stem cell transplant, the inducible caspase-9 gene (iC9) safety switch expressed by donor-derived T lymphocytes efficiently controls acute graft versus host disease (GvHD). However, in vivo elimination of iC9-T cells by the chemical inducer of dimerization (CID) that activates the iC9 protein is incomplete. To study this effect, we characterized the clonal diversity and dynamics of vector insertion sites (VIS) in iC9-T cells pre- and post-CID administration in four patients who developed GvHD. We identified 3,203 VIS among four patients and followed their in vivo clonal dynamics up to 161 days post-CID. VIS were categorized by their proximity to host genome elements, gene associations, and cis-modulatory relationship to mapped promoters. We found that VIS are preferentially located near open chromatin and promoter regions; furthermore, there was no evidence for selection bias among VIS surviving the CID treatment. The majority of iC9-T cells with high normalized VIS copy number at the time of GvHD onset were eliminated by CID, while iC9-T cells detectable post-CID generally have low normalized VIS copy number. We propose that suboptimal iC9 transgene expression is responsible for the incomplete elimination of iC9-T cells and illustrate here by simple model how cis-modulatory influences of local genome context and T-cell receptor activation status at time of CID treatment contribute to stochastic sparing of iC9-T cells.
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http://dx.doi.org/10.1038/mt.2015.217DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4886929PMC
April 2016

Clonal Dynamics In Vivo of Virus Integration Sites of T Cells Expressing a Safety Switch.

Mol Ther 2016 04 7;24(4):736-45. Epub 2015 Dec 7.

Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, Texas, USA.

Safety switches are becoming relevant for the clinical translation of T-cell-based immunotherapies. In patients receiving an allogeneic hematopoietic stem cell transplant, the inducible caspase-9 gene (iC9) safety switch expressed by donor-derived T lymphocytes efficiently controls acute graft versus host disease (GvHD). However, in vivo elimination of iC9-T cells by the chemical inducer of dimerization (CID) that activates the iC9 protein is incomplete. To study this effect, we characterized the clonal diversity and dynamics of vector insertion sites (VIS) in iC9-T cells pre- and post-CID administration in four patients who developed GvHD. We identified 3,203 VIS among four patients and followed their in vivo clonal dynamics up to 161 days post-CID. VIS were categorized by their proximity to host genome elements, gene associations, and cis-modulatory relationship to mapped promoters. We found that VIS are preferentially located near open chromatin and promoter regions; furthermore, there was no evidence for selection bias among VIS surviving the CID treatment. The majority of iC9-T cells with high normalized VIS copy number at the time of GvHD onset were eliminated by CID, while iC9-T cells detectable post-CID generally have low normalized VIS copy number. We propose that suboptimal iC9 transgene expression is responsible for the incomplete elimination of iC9-T cells and illustrate here by simple model how cis-modulatory influences of local genome context and T-cell receptor activation status at time of CID treatment contribute to stochastic sparing of iC9-T cells.
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http://dx.doi.org/10.1038/mt.2015.217DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4886929PMC
April 2016

Human Epidermal Growth Factor Receptor 2 (HER2) -Specific Chimeric Antigen Receptor-Modified T Cells for the Immunotherapy of HER2-Positive Sarcoma.

J Clin Oncol 2015 May 23;33(15):1688-96. Epub 2015 Mar 23.

Nabil Ahmed, Vita S. Brawley, Meenakshi Hegde, Catherine Robertson, Alexia Ghazi, Claudia Gerken, Enli Liu, Olga Dakhova, Aidin Ashoori, Amanda Corder, Tara Gray, Gianpietro Dotti, Zhuyong Mei, Bambi Grilley, Adrian Gee, Cliona M. Rooney, Malcolm K. Brenner, Helen E. Heslop, and Stephen Gottschalk, Center for Cell and Gene Therapy, Texas Children's Hospital, Baylor College of Medicine, Houston Methodist Hospital; Nabil Ahmed, Vita S. Brawley, Meenakshi Hegde, Catherine Robertson, Alexia Ghazi, Claudia Gerken, Enli Liu, Olga Dakhova, Aidin Ashoori, Amanda Corder, Tara Gray, John Hicks, Nino Rainusso, Zhuyong Mei, Bambi Grilley, Adrian Gee, Cliona M. Rooney, Malcolm K. Brenner, Helen E. Heslop, Lisa L. Wang, and Stephen Gottschalk, Texas Children's Cancer Center, Texas Children's Hospital, Baylor College of Medicine; Nabil Ahmed, Vita S. Brawley, Meenakshi Hegde, Catherine Robertson, Alexia Ghazi, Claudia Gerken, Enli Liu, Olga Dakhova, Aidin Ashoori, Amanda Corder, Tara Gray, Meng-Fen Wu, Hao Liu, John Hicks, Nino Rainusso, Gianpietro Dotti, Zhuyong Mei, Bambi Grilley, Adrian Gee, Cliona M. Rooney, Malcolm K. Brenner, Helen E. Heslop, Lisa L. Wang, and Stephen Gottschalk, Baylor College of Medicine; Peter Anderson, The University of Texas MD Anderson Cancer Center, Houston, TX; Peter Anderson, Levine Children's Hospital, Levine Cancer Institute, Carolinas Healthcare System, Charlotte NC; and Winfried S. Wels, Georg-Speyer-Haus, Institute for Tumor Biology and Experimental Therapy, Frankfurt, Germany.

Purpose: The outcome for patients with metastatic or recurrent sarcoma remains poor. Adoptive therapy with tumor-directed T cells is an attractive therapeutic option but has never been evaluated in sarcoma.

Patients And Methods: We conducted a phase I/II clinical study in which patients with recurrent/refractory human epidermal growth factor receptor 2 (HER2) -positive sarcoma received escalating doses (1 × 10(4)/m(2) to 1 × 10(8)/m(2)) of T cells expressing an HER2-specific chimeric antigen receptor with a CD28.ζ signaling domain (HER2-CAR T cells).

Results: We enrolled 19 patients with HER2-positive tumors (16 osteosarcomas, one Ewing sarcoma, one primitive neuroectodermal tumor, and one desmoplastic small round cell tumor). HER2-CAR T-cell infusions were well tolerated with no dose-limiting toxicity. At dose level 3 (1 × 10(5)/m(2)) and above, we detected HER2-CAR T cells 3 hours after infusion by quantitative polymerase chain reaction in 14 of 16 patients. HER2-CAR T cells persisted for at least 6 weeks in seven of the nine evaluable patients who received greater than 1 × 10(6)/m(2) HER2-CAR T cells (P = .005). HER2-CAR T cells were detected at tumor sites of two of two patients examined. Of 17 evaluable patients, four had stable disease for 12 weeks to 14 months. Three of these patients had their tumor removed, with one showing ≥ 90% necrosis. The median overall survival of all 19 infused patients was 10.3 months (range, 5.1 to 29.1 months).

Conclusion: This first evaluation of the safety and efficacy of HER2-CAR T cells in patients with cancer shows the cells can persist for 6 weeks without evident toxicities, setting the stage for studies that combine HER2-CAR T cells with other immunomodulatory approaches to enhance their expansion and persistence.
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http://dx.doi.org/10.1200/JCO.2014.58.0225DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4429176PMC
May 2015

Early transduction produces highly functional chimeric antigen receptor-modified virus-specific T-cells with central memory markers: a Production Assistant for Cell Therapy (PACT) translational application.

J Immunother Cancer 2015 18;3. Epub 2015 Feb 18.

Center for Cell and Gene Therapy Baylor College of Medicine Texas Children's Hospital Houston Methodist Hospital, Houston, TX 77030 USA.

Background: Virus-specific T-cells (VSTs) proliferate exponentially after adoptive transfer into hematopoietic stem cell transplant (HSCT) recipients, eliminate virus infections, then persist and provide long-term protection from viral disease. If VSTs behaved similarly when modified with tumor-specific chimeric antigen receptors (CARs), they should have potent anti-tumor activity. This theory was evaluated by Cruz et al. in a previous clinical trial with CD19.CAR-modified VSTs, but there was little apparent expansion of these cells in patients. In that study, VSTs were gene-modified on day 19 of culture and we hypothesized that by this time, sufficient T-cell differentiation may have occurred to limit the subsequent proliferative capacity of the transduced T-cells. To facilitate the clinical testing of this hypothesis in a project supported by the NHLBI-PACT mechanism, we developed and optimized a good manufacturing practices (GMP) compliant method for the early transduction of VSTs directed to Epstein-Barr virus (EBV), Adenovirus (AdV) and cytomegalovirus (CMV) using a CAR directed to the tumor-associated antigen disialoganglioside (GD2).

Results: Ad-CMVpp65-transduced EBV-LCLs effectively stimulated VSTs directed to all three viruses (triVSTs). Transduction efficiency on day three was increased in the presence of cytokines and high-speed centrifugation of retroviral supernatant onto retronectin-coated plates, so that under optimal conditions up to 88% of tetramer-positive VSTs expressed the GD2.CAR. The average transduction efficiency of early-and late transduced VSTs was 55 ± 4% and 22 ± 5% respectively, and early-transduced VSTs maintained higher frequencies of T cells with central memory or intermediate memory phenotypes. Early-transduced VSTs also had higher proliferative capacity and produced higher levels of TH1 cytokines IL-2, TNF-α, IFN-γ, MIP-1α, MIP-1β and other cytokines in vitro.

Conclusions: We developed a rapid and GMP compliant method for the early transduction of multivirus-specific T-cells that allowed stable expression of high levels of a tumor directed CAR. Since a proportion of early-transduced CAR-VSTs had a central memory phenotype, they should expand and persist in vivo, simultaneously protecting against infection and targeting residual malignancy. This manufacturing strategy is currently under clinical investigation in patients receiving allogeneic HSCT for relapsed neuroblastoma and B-cell malignancies (NCT01460901 using a GD2.CAR and NCT00840853 using a CD19.CAR).
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http://dx.doi.org/10.1186/s40425-015-0049-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4346112PMC
March 2015

Stromal TGF-β signaling induces AR activation in prostate cancer.

Oncotarget 2014 Nov;5(21):10854-69

Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030.

AR signaling is essential for the growth and survival of prostate cancer (PCa), including most of the lethal castration-resistant PCa (CRPC). We previously reported that TGF-β signaling in prostate stroma promotes prostate tumor angiogenesis and growth. By using a PCa/stroma co-culture model, here we show that stromal TGF-β signaling induces comprehensive morphology changes of PCa LNCaP cells. Furthermore, it induces AR activation in LNCaP cells in the absence of significant levels of androgen, as evidenced by induction of several AR target genes including PSA, TMPRSS2, and KLK4. SD-208, a TGF-β receptor 1 specific inhibitor, blocks this TGF-β induced biology. Importantly, stromal TGF-β signaling together with DHT induce robust activation of AR. MDV3100 effectively blocks DHT-induced, but not stromal TGF-β signaling induced AR activation in LNCaP cells, indicating that stromal TGF-β signaling induces both ligand-dependent and ligand-independent AR activation in PCa. TGF-β induces the expression of several growth factors and cytokines in prostate stromal cells, including IL-6, and BMP-6. Interestingly, BMP-6 and IL-6 together induces robust AR activation in these co-cultures, and neutralizing antibodies against BMP-6 and IL-6 attenuate this action. Altogether, our study strongly suggests tumor stromal microenvironment induced AR activation as a direct mechanism of CRPC.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4279415PMC
http://dx.doi.org/10.18632/oncotarget.2536DOI Listing
November 2014

Closely related T-memory stem cells correlate with in vivo expansion of CAR.CD19-T cells and are preserved by IL-7 and IL-15.

Blood 2014 Jun 29;123(24):3750-9. Epub 2014 Apr 29.

Center for Cell and Gene Therapy, Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX; Department of Medicine, Baylor College of Medicine, Houston, TX; Texas Children's Hospital, Houston, TX.

Adoptive transfer of T lymphocytes expressing a CD19-specific chimeric antigen receptor (CAR.CD19) induces complete tumor regression in patients with lymphoid malignancies. Although in vivo persistence of CAR-T cells correlates with clinical responses, it remains unknown whether specific cell subsets within the CAR-T-cell product correlate with their subsequent in vivo expansion and persistence. We analyzed 14 patients with B-cell malignancies infused with autologous CAR.CD19-redirected T cells expanded ex vivo using IL-2, and found that their in vivo expansion only correlated with the frequency within the infused product of a CD8(+)CD45RA(+)CCR7(+) subset, whose phenotype is closest to "T-memory stem cells." Preclinical models showed that increasing the frequency of CD8(+)CD45RA(+)CCR7(+) CAR-T cells in the infused line by culturing the cells with IL-7 and IL-15 produced greater antitumor activity of CAR-T cells mediated by increased resistance to cell death, following repetitive encounters with the antigen, while preserving their migration to secondary lymphoid organs. This trial was registered at www.clinicaltrials.gov as #NCT00586391 and #NCT00709033.
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http://dx.doi.org/10.1182/blood-2014-01-552174DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4055922PMC
June 2014

Genes upregulated in prostate cancer reactive stroma promote prostate cancer progression in vivo.

Clin Cancer Res 2014 Jan 22;20(1):100-9. Epub 2013 Oct 22.

Authors' Affiliations: Departments of Pathology and Immunology and Molecular and Cellular Biology, Baylor College of Medicine; and Michael E. DeBakey Department of Veterans Affairs Medical Center, Houston, Texas.

Purpose: Marked reactive stroma formation is associated with poor outcome in clinically localized prostate cancer. We have previously identified genes with diverse functions that are upregulated in reactive stroma. This study tests the hypothesis that expression of these genes in stromal cells enhances prostate cancer growth in vivo.

Experimental Design: The expression of reactive stroma genes in prostate stromal cell lines was evaluated by reverse transcriptase (RT)-PCR and qRT-PCR. Genes were knocked down using stable expression of short-hairpin RNAs (shRNA) and the impact on tumorigenesis assessed using the differential reactive stroma (DRS) system, in which prostate stromal cell lines are mixed with LNCaP prostate cancer cells and growth as subcutaneous xenografts assessed.

Results: Nine of 10 reactive stroma genes tested were expressed in one or more prostate stromal cell lines. Gene knockdown of c-Kit, Wnt10B, Bmi1, Gli2, or COMP all resulted in decreased tumorigenesis in the DRS model. In all tumors analyzed, angiogenesis was decreased and there were variable effects on proliferation and apoptosis in the LNCaP cells. Wnt10B has been associated with stem/progenitor cell phenotype in other tissue types. Using a RT-PCR array, we detected downregulation of multiple genes involved in stem/progenitor cell biology such as OCT4 and LIF as well as cytokines such as VEGFA, BDNF, and CSF2 in cells with Wnt10B knockdown.

Conclusions: These findings show that genes upregulated in prostate cancer-reactive stroma promote progression when expressed in prostate stromal cells. Moreover, these data indicate that the DRS model recapitulates key aspects of cancer cell/reactive stroma interactions in prostate cancer.
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http://dx.doi.org/10.1158/1078-0432.CCR-13-1184DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3947312PMC
January 2014

Endocrine fibroblast growth factor FGF19 promotes prostate cancer progression.

Cancer Res 2013 Apr 25;73(8):2551-62. Epub 2013 Feb 25.

Department of Pathology and Immunology and Michael E. DeBakey Department of Veterans Affairs Medical Center, Baylor College of Medicine, Houston, TX 77030, USA.

Prostate cancer is the most common visceral malignancy and the second leading cause of cancer deaths in US men. There is broad evidence that fibroblast growth factor (FGF) receptors are important in prostate cancer initiation and progression, but the contribution of particular FGFs in this disease is not fully understood. The FGF family members FGF19, FGF21, and FGF23 comprise a distinct subfamily that circulate in serum and act in an endocrine manner. These endocrine FGFs require α-Klotho (KL) and/or β-Klotho (KLB), two related single-pass transmembrane proteins restricted in their tissue distribution, to act as coreceptors along with classic FGF receptors (FGFR) to mediate potent biologic activity. Here we show that FGF19 is expressed in primary and metastatic prostate cancer tissues, where it functions as an autocrine growth factor. Exogenous FGF19 promoted the growth, invasion, adhesion, and colony formation of prostate cancer cells at low ligand concentrations. FGF19 silencing in prostate cancer cells expressing autocrine FGF19 decreased invasion and proliferation in vitro and tumor growth in vivo. Consistent with these observations, KL and/or KLB were expressed in prostate cancer cells in vitro and in vivo, raising the possibility that additional endocrine FGFs may also exert biologic effects in prostate cancer. Our findings support the concept that therapies targeting FGFR signaling may have efficacy in prostate cancer and highlight FGF19 as a relevant endocrine FGF in this setting.
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http://dx.doi.org/10.1158/0008-5472.CAN-12-4108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3630260PMC
April 2013

Notch and TGFβ form a reciprocal positive regulatory loop that suppresses murine prostate basal stem/progenitor cell activity.

Cell Stem Cell 2012 Nov;11(5):676-88

Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.

The role of Notch signaling in the maintenance of adult murine prostate epithelial homeostasis remains unclear. We found that Notch ligands are mainly expressed within the basal cell lineage, while active Notch signaling is detected in both the prostate basal and luminal cell lineages. Disrupting the canonical Notch effector Rbp-j impairs the differentiation of prostate basal stem cells and increases their proliferation in vitro and in vivo, but does not affect luminal cell biology. Conversely, ectopic Notch activation in adult prostates results in a decrease in basal cell number and luminal cell hyperproliferation. TGFβ dominates over Notch signaling and overrides Notch ablation-induced proliferation of prostate basal cells. However, Notch confers sensitivity and positive feedback by upregulating a plethora of TGFβ signaling components including TgfβR1. These findings reveal crucial roles of the self-enforced positive reciprocal regulatory loop between TGFβ and Notch in maintaining prostate basal stem cell dormancy.
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http://dx.doi.org/10.1016/j.stem.2012.07.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3490134PMC
November 2012

FGFR-4 Arg³⁸⁸ enhances prostate cancer progression via extracellular signal-related kinase and serum response factor signaling.

Clin Cancer Res 2011 Jul 27;17(13):4355-66. Epub 2011 May 27.

Department of Pathology, Baylor College of Medicine, Houston, Texas, USA.

Purpose: Increased expression of FGFR-4 and its ligands have been linked to lethal prostate cancer (PCa). Furthermore, a germ line polymorphism in the FGFR-4 gene, resulting in arginine at codon 388 (Arg³⁸⁸) instead of glycine (Gly³⁸⁸), is associated with aggressive disease. The FGFR-4 Arg³⁸⁸ variant results in increased receptor stability, sustained receptor activation, and increased motility and invasion compared with Gly³⁸⁸. However, the impact of sustained signaling on cellular signal transduction pathways is unknown.

Experimental Design: Expression microarray analysis of immortalized prostatic epithelial cells lines expressing FGFR-4 Arg³⁸⁸ or Gly³⁸⁸ was used to establish a gene signature associated with FGFR-4 Arg³⁸⁸ expression. Transient transfection of reporters and inhibitors was used to establish the pathways activated by FGFR-4 Arg³⁸⁸ expression. The impact of pathway knockdown in vitro and in an orthotopic model was assessed using inhibitors and/or short hairpin RNA (shRNA).

Results: Expression of the FGFR-4 Arg³⁸⁸ protein leads to increased activity of the extracellular signal-related kinase (ERK) pathway, increased activity of serum response factor (SRF) and AP1, and transcription of multiple genes that are correlated with aggressive clinical behavior in PCa. Increased expression of SRF is associated with biochemical recurrence in men undergoing radical prostatectomy. Consistent with these observations, knockdown of FGFR-4 Arg³⁸⁸ in PCa cells decreases proliferation and invasion in vitro and primary tumor growth and metastasis in vivo.

Conclusions: These studies define a signal transduction pathway downstream of FGFR-4 Arg³⁸⁸ that acts via ERK and SRF to promote PCa progression.
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http://dx.doi.org/10.1158/1078-0432.CCR-10-2858DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3131485PMC
July 2011

Global gene expression analysis of reactive stroma in prostate cancer.

Clin Cancer Res 2009 Jun 9;15(12):3979-89. Epub 2009 Jun 9.

Departments of Patholog, Baylor College of Medicine, and Michael E DeBakey Veterans Affairs Medical Center, Houston, Texas 77030, USA.

Purpose: Marked reactive stroma formation, designated as grade 3 reactive stroma, is associated with poor outcome in clinically localized prostate cancer. To understand the biological processes and signaling mechanisms underlying the formation of such reactive stroma, we carried out microarray gene expression analysis of laser-captured reactive stroma and matched normal stroma.

Experimental Design: Seventeen cases of reactive stroma grade 3 cancer were used to laser-capture tumor and normal stroma. Expression analysis was carried out using Agilent 44K arrays. Up-regulation of selected genes was confirmed by quantitative reverse transcription-PCR. Expression data was analyzed to identify significantly up- and down-regulated genes, and gene ontology analysis was used to define pathways altered in reactive stroma.

Results: A total of 544 unique genes were significantly higher in the reactive stroma and 606 unique genes were lower. Gene ontology analysis revealed significant alterations in a number of novel processes in prostate cancer reactive stroma, including neurogenesis, axonogenesis, and the DNA damage/repair pathways, as well as evidence of increases in stem cells in prostate cancer reactive stroma.

Conclusions: Formation of reactive stroma in prostate cancer is a dynamic process characterized by significant alterations in growth factor and signal transduction pathways and formation of new structures, including nerves and axons.
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http://dx.doi.org/10.1158/1078-0432.CCR-08-1899DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2734921PMC
June 2009

Dickkopf-like1 regulates postpubertal spermatocyte apoptosis and testosterone production.

Endocrinology 2009 Jan 25;150(1):404-12. Epub 2008 Sep 25.

Department of Molecular and Human Genetics, Baylor College of Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA.

Dickkopf-like1 (Dkkl1) encodes a glycoprotein secreted by postmeiotic male germ cells. We report here that adult Dkkl1-deficient males have elevated sperm counts caused by a decrease in postpubertal spermatocyte apoptosis and display, upon aging, increased local production of testosterone. Molecular analyses identified the Fas death ligand (FasL) as a target for Dkkl1 pro-apoptotic activity in adult mice. Accordingly, adult FasL-deficient gld mice display an increased sperm count and decreased spermatocyte apoptosis phenotype similar to the one observed in Dkkl1-deficient mice. We also show that the elevated testosterone level observed in aging Dkkl1-deficient males is secondary to increased expression in Leydig cells of CYP11A and CYP17, two genes implicated in steroidogenesis. Furthermore, treatment of Leydig cells with Dkkl1 decreases DNA binding and transcriptional activity of steroidogenic factor 1, a pivotal regulator of gene expression in testis. Thus, this study establishes Dkkl1 as a negative regulator of adult testis homeostasis and identifies a novel, Dkkl1/FasL-dependent, regulation that specifically controls the number of postpubertal spermatocytes.
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http://dx.doi.org/10.1210/en.2008-0673DOI Listing
January 2009