Debio 0617B Inhibits Growth of STAT3-Driven Solid Tumors through Combined Inhibition of JAK, SRC, and Class III/V Receptor Tyrosine Kinases

Tumor survival, metastases, chemoresistance, and escape from immune responses have been associated with inappropriate activation of STAT3 and/or STAT5 in various cancers, including solid tumors. Debio 0617B has been developed as a first-in-class kinase inhibitor with a unique profile targeting phospho-STAT3 (pSTAT3) and/or pSTAT5 in tumors through combined inhibition of JAK, SRC, ABL, and class III/V receptor tyrosine kinases (RTK). Debio 0617B showed dose-dependent inhibition of pSTAT3 in STAT3-activated carcinoma cell lines; Debio 0617B also showed potent antiproliferative activity in a panel of cancer cell lines and in patient-derived tumor xenografts tested in an in vitro clonogenic assay. Debio 0617B showed in vivo efficacy by inhibiting tumor growth in several mouse xenograft models. To increase in vivo efficacy and STAT3 inhibition, Debio 0617B was tested in combination with the EGFR inhibitor erlotinib in a non-small cell lung cancer xenograft model. To evaluate the impact of in vivo STAT3 blockade on metastases, Debio 0617B was tested in an orthotopic tumor model. Measurement of primary tumor weight and metastatic counts in lung tissue demonstrated therapeutic efficacy of Debio 0617B in this model. These data show potent activity of Debio 0617B on a broad spectrum of STAT3-driven solid tumors and synergistic activity in combination with EGFR inhibition. (C) 2016 AACR.

Lymphatic vessel density is associated with CD8(+) T cell infiltration and immunosuppressive factors in human melanoma

Natacha Anne-Sophie Bordry, Maria Anna Sofia Broggi, Esther Danenberg, Manuel Andreas Fankhauser, Olivier Michielin, Timothy Murray, Melody Swartz

Increased density of tumor-associated lymphatic vessels correlates with poor patient survival in melanoma and other cancers, yet lymphatic drainage is essential for initiating an immune response. Here we asked whether and how lymphatic vessel density (LVD) correlates with immune cell infiltration in primary tumors and lymph nodes (LNs) from patients with cutaneous melanoma. Using immunohistochemistry and quantitative image analysis, we found significant positive correlations between LVD and CD8(+) T cell infiltration as well as expression of the immunosuppressive molecules inducible nitric oxide synthase (iNOS) and 2,3-dioxygenase (IDO). Interestingly, similar associations were seen in tumor-free LNs adjacent to metastatic ones, indicating loco-regional effects of tumors. Our data suggest that lymphatic vessels play multiple roles at tumor sites and LNs, promoting both T cell infiltration and adaptive immunosuppressive mechanisms. Lymph vessel associated T cell infiltration may increase immunotherapy success rates provided that the treatment overcomes adaptive immune resistance.

TAYLOR & FRANCIS INC2018

Anti-angiogenic immunotherapy for lung cancer

Ece Kadioglu

Lung cancer is the leading cause of cancer-associated deaths worldwide. Platinum-based chemotherapy is the most common therapeutic approach in advanced non-small cell lung cancer (NSCLC), particularly for tumors that carry non-druggable activating mutations. However, these tumors are generally not eradicated when diagnosed at an advanced stage and are frequently resistant to chemotherapy. Therefore, there is an urgent medical need for new treatments for this frequent cancer type. Immunotherapies are treatments based on increasing the strength of immune responses against cancer. In particular, monoclonal antibodies that block inhibitory "immune-checkpoints" expressed on T cells (e.g., programmed cell death protein 1, or PD1) show clinical efficacy in increasing tumor types. However, these therapies improve survival in only a minority of NSCLC patients, and ongoing efforts are being made for increasing their efficacy through combinatorial treatments. In this regard, growing evidence indicates that tumor angiogenesis is closely associated with immunosuppression. Pro-angiogenic factors, such as vascular endothelial growth factor A (VEGFA) and angiopoietin 2 (ANG2), cause abnormalities and dysfunctions in tumor blood vessels that impair T cell extravasation and anti-tumoral activity. Recent findings in preclinical cancer models show that reprogramming the features of tumor-associated blood vessels by anti-angiogenic drugs may help to increase intratumoral T cell abundance and sensitize refractory tumors to immunotherapy. Nevertheless, the potential of anti-angiogenics in the context of lung cancer immunotherapy is poorly understood. Therefore, the main objective of my project was to audit combinations of anti-angiogenic therapy and immune checkpoint blockade in a genetically engineered mouse model of NSCLC. I first studied the anti-tumoral activity of dual VEGFA and ANG2 inhibition using a bispecific antibody (A2V) in the KrasLSL-G12D/+;p53fl/fl (KP) NSCLC model. I found that A2V, but not single VEGFA or ANG2 blockade, had robust tumor-inhibitory activity in KP mice, which was at least comparable to standard-of-care chemotherapy. However, A2V only moderately increased cytotoxic T cells in the tumors. To potentially increase the immunogenicity of KP tumors, I also generated two KP mouse variants by either co-expressing a surrogate neoantigen or genetically deleting a DNA mismatch repair enzyme in the cancer cells. However, the therapeutic efficacy of A2V was not further improved in spite of a slightly more activated immune response. I next investigated combination therapies involving A2V and PD1 blockade. In contrast to previous findings in other cancer types, the addition of PD1 antibodies deteriorated the efficacy of A2V, likely through enhancing immunosuppressive mechanisms sustained, at least in part, by regulatory T cells and T cell-antagonizing cytokines. In summary, my work supports the potential clinical efficacy of combined VEGFA and ANG2 blockade for lung cancer therapy but provided little evidence for its synergy in association with anti-PD1 therapy.

EPFL2019

Bioengineering Methods to Improve in vitro Adoptive Cell Therapy based on Tumor-Infiltrating Lymphocytes

François Réal Rivest

Cancer is one of the biggest medical challenges of our times, with a devastating impact across all social categories. Accordingly, considerable efforts are geared towards improving the standard of care. Among them, immunotherapy, which relies on the immune system's capacity to fight cancer cells, brings new hope for higher success rates and in some cases even a cure of this devastating disease. A particularly interesting approach called adoptive cell therapy, or ACT, is based on immune cells that have infiltrated tumors and have the potential to fight them. Unfortunately, these tumor-infiltrating lymphocytes (TILs) are very rare and their activity is often suppressed by components of the tumor microenvironment (TME). However, TILs can be extracted from tumor biopsies, reactivated and expanded in vitro before being reinjected into the patient. This immunotherapy strategy has shown impressive results in melanoma, where a majority of patients have seen a complete tumor remission. However, for most solid cancers (e.g. lung or colorectal cancer) that are in general less prone to mount immune responses, this approach is less effective. Other reasons for the currently limited success rate of ACT include the ineffectiveness to expand TILs in vitro, as well as the lack of functional assays to probe their potency after culture. Indeed, existing tumor models are based either on the non-physiological culture of cancer cell lines on plastic dishes or on the implantation of a patient's tumor tissue into an immune-deficient mouse, an assay that is highly complex, inefficient and expensive. Recent breakthroughs in 3D primary cell culture technology have provided paths forward in overcoming these challenges. In particular, the derivation of patient-derived miniaturized tumors, or tumoroids, has enabled the recapitulation of some key functional characteristics of real tumors. When co-cultured with fibroblasts or immune cells, tumoroids are potentially powerful models for immunotherapy applications. However, despite promising proof-of-concept demonstrations of modeling the TME with such heterotypic tumoroids, it has neither been possible to derive such complex in vitro tumor models with all key cell types isolated from the same patient's tumor, nor to maintain the numbers and phenotypes of TME-derived cells in longer-term cultures. Moreover, existing tumoroids are highly heterogeneous and unsuitable for the development of scalable and reproducible assays that are needed in diagnostic applications. This thesis focused on the bioengineering of novel in vitro tools to address some of the aforementioned obstacles in realizing the promise of TIL therapy. First, to generate heterotypic and autologous tumoroids, existing protocols were optimized to isolate and expand cancer cells, fibroblasts, and TILs from colorectal cancer (CRC) samples. A small biobank was established for each cell type as a resource for the development and application of patient-specific tumoroid assays. In the second part of this thesis, a heterotypic CRC tumoroid platform was developed for testing autologous TIL potency in combination with immunotherapeutic agents. CRC tumoroids were derived in high-throughput on a hydrogel substrate comprising an array of regularly spaced, round-bottom microcavities, a set-up that was found to highly amenable to quantitative experimentation. ... More in the full text ...