Lack of immunoediting in murine pancreatic cancer reversed with neoantigen

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Abstract

In carcinogen-driven cancers, a high mutational burden results in neoepitopes that can be recognized immunologically. Such carcinogen-induced tumors may evade this immune response through “immunoediting,” whereby tumors adapt to immune pressure and escape T cell–mediated killing. Many tumors lack a high neoepitope burden, and it remains unclear whether immunoediting occurs in such cases. Here, we evaluated T cell immunity in an autochthonous mouse model of pancreatic cancer and found a low mutational burden, absence of predicted neoepitopes derived from tumor mutations, and resistance to checkpoint immunotherapy. Spontaneous tumor progression was identical in the presence or absence of T cells. Moreover, tumors arising in T cell–depleted mice grew unchecked in immune-competent hosts. However, introduction of the neoantigen ovalbumin (OVA) led to tumor rejection and T cell memory, but this did not occur in OVA immune-tolerant mice. Thus, immunoediting does not occur in this mouse model — a likely consequence, not a cause, of absent neoepitopes. Because many human tumors also have a low missense mutational load and minimal neoepitope burden, our findings have clinical implications for the design of immunotherapy for patients with such tumors.

Authors

Rebecca A. Evans, Mark S. Diamond, Andrew J. Rech, Timothy Chao, Max W. Richardson, Jeffrey H. Lin, David L. Bajor, Katelyn T. Byrne, Ben Z. Stanger, James L. Riley, Nune Markosyan, Rafael Winograd, Robert H. Vonderheide

Platelet integrin α6β1 controls lung metastasis through direct binding to cancer cell–derived ADAM9

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Abstract

Metastatic dissemination of cancer cells, which accounts for 90% of cancer mortality, is the ultimate hallmark of malignancy. Growing evidence suggests that blood platelets have a predominant role in tumor metastasis; however, the molecular mechanisms involved remain elusive. Here, we demonstrate that genetic deficiency of integrin α6β1 on platelets markedly decreases experimental and spontaneous lung metastasis. In vitro and in vivo assays reveal that human and mouse platelet α6β1 supports platelet adhesion to various types of cancer cells. Using a knockdown approach, we identified ADAM9 as the major counter receptor of α6β1 on both human and mouse tumor cells. Static and flow-based adhesion assays of platelets binding to DC-9, a recombinant protein covering the disintegrin-cysteine domain of ADAM9, demonstrated that this receptor directly binds to platelet α6β1. In vivo studies showed that the interplay between platelet α6β1 and tumor cell–expressed ADAM9 promotes efficient lung metastasis. The integrin α6β1–dependent platelet-tumor cell interaction induces platelet activation and favors the extravasation process of tumor cells. Finally, we demonstrate that a pharmacological approach targeting α6β1 efficiently impairs tumor metastasis through a platelet-dependent mechanism. Our study reveals a mechanism by which platelets promote tumor metastasis and suggests that integrin α6β1 represents a promising target for antimetastatic therapies.

Authors

Elmina Mammadova-Bach, Paola Zigrino, Camille Brucker, Catherine Bourdon, Monique Freund, Adèle De Arcangelis, Scott I. Abrams, Gertaud Orend, Christian Gachet, Pierre Henri Mangin

Epigenetic remodeling regulates transcriptional changes between ovarian cancer and benign precursors

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Abstract

Regulation of lineage-restricted transcription factors has been shown to influence malignant transformation in several types of cancer. Whether similar mechanisms are involved in ovarian cancer pathogenesis is unknown. PAX8 is a nuclear transcription factor that controls the embryologic development of the Müllerian system, including the fallopian tubes. Recent studies have shown that fallopian tube secretory epithelial cells (FTSECs) give rise to the most common form of ovarian cancer, high-grade serous ovarian carcinomas (HGSOCs). We designed the present study in order to understand whether changes in gene expression between FTSECs and HGSOCs relate to alterations in PAX8 binding to chromatin. Using whole transcriptome shotgun sequencing (RNA-Seq) after PAX8 knockdown and ChIP-Seq, we show that FTSECs and HGSOCs are distinguished by marked reprogramming of the PAX8 cistrome. Genes that are significantly altered between FTSECs and HGSOCs are enriched near PAX8 binding sites. These sites are also near TEAD binding sites, and these transcriptional changes may be related to PAX8 interactions with the TEAD/YAP1 signaling pathway. These data suggest that transcriptional changes after transformation in ovarian cancer are closely related to epigenetic remodeling in lineage-specific transcription factors.

Authors

Kevin M. Elias, Megan M. Emori, Thomas Westerling, Henry Long, Anna Budina-Kolomets, Fugen Li, Emily MacDuffie, Michelle R. Davis, Alexander Holman, Brian Lawney, Matthew L. Freedman, John Quackenbush, Myles Brown, Ronny Drapkin

An imaging agent to detect androgen receptor and its active splice variants in prostate cancer

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Abstract

Constitutively active splice variants of androgen receptor (AR-Vs) lacking ligand-binding domain (LBD) are a mechanism of resistance to androgen receptor LBD–targeted (AR LBD–targeted) therapies for metastatic castration-resistant prostate cancer (CRPC). There is a strong unmet clinical need to identify prostate cancer patients with AR-V–positive lesions to determine whether they will benefit from further AR LBD–targeting therapies or should receive taxanes or investigational drugs like EPI-506 or galeterone. Both EPI-506 (NCT02606123) and galeterone (NCT02438007) are in clinical trials and are proposed to have efficacy against lesions that are positive for AR-Vs. AR activation function-1 (AF-1) is common to the N-terminal domains of full-length AR and AR-Vs. Here, we provide proof of concept for developing imaging compounds that directly bind AR AF-1 to detect both AR-Vs and full-length AR. ¹²³I-EPI-002 had specific binding to AR AF-1, which enabled direct visualization of CRPC xenografts that express full-length AR and AR-Vs. Our findings highlight the potential of ¹²³I-EPI-002 as an imaging agent for the detection of full-length AR and AR-Vs in CRPC.

Authors

Yusuke Imamura, Amy H. Tien, Jinhe Pan, Jacky K. Leung, Carmen A. Banuelos, Kunzhong Jian, Jun Wang, Nasrin R. Mawji, Javier Garcia Fernandez, Kuo-Shyan Lin, Raymond J. Andersen, Marianne D. Sadar

PD-1⁺ and Foxp3⁺ T cell reduction correlates with survival of HCC patients after sorafenib therapy

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Abstract

BACKGROUND. Sorafenib is an oral antiangiogenic agent administered in advanced-stage hepatocellular carcinoma (HCC). Based on preclinical and human studies, we hypothesized that, in addition to its antiangiogenic properties, sorafenib may beneficially reduce the extent of the immunosuppressive network in HCC patients. To test this hypothesis, we examined whether alterations in the immunosuppressive burden of advanced-stage HCC patients correlated with clinical outcome.

METHODS. In before and after sorafenib treatment, blood samples collected from 19 patients with advanced HCC, the frequency of PD-1⁺ T cells, Tregs, and myeloid derived suppressor cells (MDSC) were quantified by multiparameter FACS. Cytokine levels in plasma were determined by ELISA.

RESULTS. Overall survival (OS) was significantly impacted by the reduction in the absolute number of both CD4⁺PD-1⁺ T cells and CD8⁺PD-1⁺ T cells following sorafenib treatment. Significant decreases in the frequency and absolute number of Foxp3⁺ Tregs were also observed, and a statistically significant improvement in OS was noted in patients exhibiting a greater decrease in the number of Foxp3⁺ Tregs. The ratio of CD4⁺CD127⁺PD-1^– T effector cells to CD4⁺Foxp3⁺PD-1⁺ Tregs was significantly increased following treatment with sorafenib. Increased frequency of CD4⁺CD127⁺ T effector cells in the posttreatment samples significantly correlated with OS.

CONCLUSION. This study is the first to our knowledge to demonstrate the potent immunomodulatory effects of sorafenib therapy on PD-1⁺ T cells and Tregs and the ensuing correlation with survival. These phenotypes could serve as predictive biomarkers to identify HCC patients who are likely to benefit from sorafenib treatment.

TRIAL REGISTRATION. Registration is not required for observational studies.

FUNDING. This study was supported by NCI Core Grant to RPCI (NIH P30 CA016056) and discretionary funds to Y. Thanavala.

Authors

Suresh Gopi Kalathil, Amit Anand Lugade, Austin Miller, Renuka Iyer, Yasmin Thanavala

Deep sequencing reveals microRNAs predictive of antiangiogenic drug response

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Abstract

The majority of metastatic renal cell carcinoma (RCC) patients are treated with tyrosine kinase inhibitors (TKI) in first-line treatment; however, a fraction are refractory to these antiangiogenic drugs. MicroRNAs (miRNAs) are regulatory molecules proven to be accurate biomarkers in cancer. Here, we identified miRNAs predictive of progressive disease under TKI treatment through deep sequencing of 74 metastatic clear cell RCC cases uniformly treated with these drugs. Twenty-nine miRNAs were differentially expressed in the tumors of patients who progressed under TKI therapy (P values from 6 × 10^–9 to 3 × 10^–3). Among 6 miRNAs selected for validation in an independent series, the most relevant associations corresponded to miR–1307-3p, miR–155-5p, and miR–221-3p (P = 4.6 × 10^–3, 6.5 × 10^–3, and 3.4 × 10^–2, respectively). Furthermore, a 2 miRNA–based classifier discriminated individuals with progressive disease upon TKI treatment (AUC = 0.75, 95% CI, 0.64–0.85; P = 1.3 × 10^–4) with better predictive value than clinicopathological risk factors commonly used. We also identified miRNAs significantly associated with progression-free survival and overall survival (P = 6.8 × 10^–8 and 7.8 × 10^–7 for top hits, respectively), and 7 overlapped with early progressive disease. In conclusion, this is the first miRNome comprehensive study, to our knowledge, that demonstrates a predictive value of miRNAs for TKI response and provides a new set of relevant markers that can help rationalize metastatic RCC treatment.

Authors

Jesús García-Donas, Benoit Beuselinck, Lucía Inglada-Pérez, Osvaldo Graña, Patrick Schöffski, Agnieszka Wozniak, Oliver Bechter, Maria Apellániz-Ruiz, Luis Javier Leandro-García, Emilio Esteban, Daniel E. Castellano, Aranzazu González del Alba, Miguel Angel Climent, Susana Hernando, José Angel Arranz, Manuel Morente, David G. Pisano, Mercedes Robledo, Cristina Rodriguez-Antona

An extra copy of p53 suppresses development of spontaneous Kras-driven but not radiation-induced cancer

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Abstract

The tumor suppressor p53 blocks tumor progression in multiple tumor types. Radiation-induced cancer following exposure to radiation therapy or space travel may also be regulated by p53 because p53 has been proposed to respond to DNA damage to suppress tumorigenesis. Here, we investigate the role of p53 in lung carcinogenesis and lymphomagenesis in LA-1 Kras^G12D mice with wild-type p53 or an extra copy of p53 (super p53) exposed to fractionated total body irradiation with low linear energy transfer (low-LET) X-rays or high-LET iron ions and compared tumor formation in these mice with unirradiated controls. We found that an additional copy of p53 suppressed both Kras-driven lung tumor and lymphoma development in the absence of radiation. However, an additional copy of p53 did not affect lymphoma development following low- or high-LET radiation exposure and was unable to suppress radiation-induced expansion of thymocytes with mutated Kras. Moreover, radiation exposure increased lung tumor size in super p53 but not wild-type p53 mice. These results demonstrate that although p53 suppresses the development of spontaneous tumors expressing Kras^G12D, in the context of exposure to ionizing radiation, an extra copy of p53 does not protect against radiation-induced lymphoma and may promote Kras^G12D mutant lung cancer.

Authors

Everett J. Moding, Hooney D. Min, Katherine D. Castle, Moiez Ali, Loretta Woodlief, Nerissa Williams, Yan Ma, Yongbaek Kim, Chang-Lung Lee, David G. Kirsch

PD-1 blockade enhances the vaccination-induced immune response in glioma

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Abstract

DC vaccination with autologous tumor lysate has demonstrated promising results for the treatment of glioblastoma (GBM) in preclinical and clinical studies. While the vaccine appears capable of inducing T cell infiltration into tumors, the effectiveness of active vaccination in progressively growing tumors is less profound. In parallel, a number of studies have identified negative costimulatory pathways, such as programmed death 1/programmed death ligand 1 (PD-1/PD-L1), as relevant mediators of the intratumoral immune responses. Clinical responses to PD-1 pathway inhibition, however, have also been varied. To evaluate the relevance to established glioma, the effects of PD-1 blockade following DC vaccination were tested in intracranial (i.c.) glioma tumor–bearing mice. Treatment with both DC vaccination and PD-1 mAb blockade resulted in long-term survival, while neither agent alone induced a survival benefit in animals with larger, established tumors. This survival benefit was completely dependent on CD8⁺ T cells. Additionally, DC vaccine plus PD-1 mAb blockade resulted in the upregulation of integrin homing and immunologic memory markers on tumor-infiltrating lymphocytes (TILs). In clinical samples, DC vaccination in GBM patients was associated with upregulation of PD-1 expression in vivo, while ex vivo blockade of PD-1 on freshly isolated TILs dramatically enhanced autologous tumor cell cytolysis. These findings strongly suggest that the PD-1/PD-L1 pathway plays an important role in the adaptive immune resistance of established GBM in response to antitumor active vaccination and provide us with a rationale for the clinical translation of this combination therapy.

Authors

Joseph P. Antonios, Horacio Soto, Richard G. Everson, Joey Orpilla, Diana Moughon, Namjo Shin, Shaina Sedighim, William H. Yong, Gang Li, Timothy F. Cloughesy, Linda M. Liau, Robert M. Prins

Mutant p53 regulates ovarian cancer transformed phenotypes through autocrine matrix deposition

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Abstract

High-grade serous ovarian carcinoma (HGS-OvCa) harbors p53 mutations and can originate from the epithelial cell compartment of the fallopian tube fimbriae. From this site, neoplastic cells detach, survive in the peritoneal cavity, and form cellular clusters that intercalate into the mesothelium to form ovarian and peritoneal masses. To examine the contribution of mutant p53 to phenotypic alterations associated with HGS-OvCA, we developed live-cell microscopy assays that recapitulate these early events in cultured fallopian tube nonciliated epithelial (FNE) cells. Expression of stabilizing mutant variants of p53, but not depletion of endogenous wild-type p53, in FNE cells promoted survival and cell-cell aggregation under conditions of cell detachment, leading to the formation of cell clusters with mesothelium-intercalation capacity. Mutant p53^R175H-induced phenotypes were dependent on fibronectin production, α5β1 fibronectin receptor engagement, and TWIST1 expression. These results indicate that FNE cells expressing stabilizing p53 mutants acquire anchorage independence and subsequent mesothelial intercalation capacity through a mechanism involving mesenchymal transition and matrix production. These findings provide important new insights into activities of mutant p53 in the cells of origin of HGS-OvCa.

Authors

Marcin P. Iwanicki, Hsing-Yu Chen, Claudia Iavarone, Ioannis K. Zervantonakis, Taru Muranen, Marián Novak, Tan A. Ince, Ronny Drapkin, Joan S. Brugge

TGF-β and VEGF cooperatively control the immunotolerant tumor environment and the efficacy of cancer immunotherapies

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Abstract

Tregs imprint an early immunotolerant tumor environment that prevents effective antitumor immune responses. Using transcriptomics of tumor tissues, we identified early upregulation of VEGF and TGF-β pathways compatible with tolerance imprinting. Silencing of VEGF or TGF-β in tumor cells induced early and pleiotropic modulation of immune-related transcriptome signatures in tumor tissues. These were surprisingly similar for both silenced tumors and related to common downstream effects on Tregs. Silencing of VEGF or TGF-β resulted in dramatically delayed tumor growth, associated with decreased Tregs and myeloid-derived suppressor cells and increased effector T cell activation in tumor infiltrates. Strikingly, co-silencing of TGF-β and VEGF led to a substantial spontaneous tumor eradication rate and the combination of their respective inhibitory drugs was synergistic. VEGF and/or TGF-β silencing also restored tumor sensitivity to tumor-specific cell therapies and markedly improved the efficacy of anti–PD-1/anti–CTLA-4 treatment. Thus, TGF-β and VEGF cooperatively control the tolerant environment of tumors and are targets for improved cancer immunotherapies.

Authors

Tristan Courau, Djamel Nehar-Belaid, Laura Florez, Béatrice Levacher, Thomas Vazquez, Faustine Brimaud, Bertrand Bellier, David Klatzmann