Immune consequences of tyrosine kinase inhibitors that synergize with cancer immunotherapy.
Posted: Tue Dec 20, 2016 7:51 am
Abstract
Combination therapy for the treatment of cancer is becoming increasingly essential as we gain improved understanding of the complexity of cancer progression and the mechanisms by which cancer cells become resistant to single-agent therapy. Recent studies, both clinical and preclinical, have suggested that immunotherapy is a promising approach to the treatment of cancer; however, strategies to improve its clinical efficacy are still needed. A number of recent studies have indicated that antiangiogenic tyrosine kinase inhibitors (TKIs) target multiple components of the tumor microenvironment and are an ideal class of agents for synergizing with cancer immunotherapy. TKIs are well known to modulate tumor endothelial cells, leading to vascular normalization; however, these agents have also been recently shown to decrease tumor compactness and tight junctions, thereby reducing solid tumor pressure and allowing for improved perfusion of collapsed vessels and increased tumor oxygenation. In addition, some TKIs are capable of inducing immunogenic modulation, whereby tumor cells are sensitized to killing by T lymphocytes. Moreover, a number of TKIs have been shown to be involved in immune subset conditioning, increasing the frequency and function of effector immune elements, while decreasing the number and function of immune suppressor cells. The alteration of the immune landscape, direct modification of tumor cells, and improved vascular perfusion leads to improved antitumor efficacy when antiangiogenic TKIs are combined with immunotherapy. Collectively, the data presented in this review support the clinical combination of multi-targeted antiangiogenic TKIs, including but not limited to cabozantinib, sunitinib, and sorafenib, as well as to other antiangiogenic therapies, such as the anti-VEGF antibody bevacizumab, with cancer vaccines for improved treatment of solid tumors.
Keywords: cabozantinib, sunitinib, immunotherapy, combination therapy, immune subset conditioning, immunogenic modulation
Conclusions
The observations reviewed here further demonstrate that TKIs induce direct effects on tumor cells leading to their destruction via apoptotic and immune-mediated mechanisms. These observations also support the conclusions that TKIs, particularly antiangiogenic TKIs, modify the tumor microenvironment in multiple ways, including the alteration of immune cell infiltration (immune subset conditioning) leading to tumor eradication particularly when these therapies are combined with cancer immunotherapy. Unfortunately, it is common for cancer cells to become resistant to targeted therapy, particularly to small molecule inhibitors such as TKIs. It is possible that drug resistance could be avoided or overcome by combining these agents with additional therapies with which synergistic antitumor effects can be observed. In addition, the effectiveness of cancer immunotherapy can be compromised when immune cells cannot penetrate the tumor due to abnormal vasculature [44]. Data obtained using the MC38-CEA tumor model indicate that TKIs synergize with the MVA/rF-CEA/TRICOM cancer vaccine to induce changes in the tumor microenvironment resulting in improved immune cell infiltration and sustained tumor regression. The antiangiogenic TKIs described here synergize with cancer immunotherapy by targeting 3 elements of the tumor microenvironment: (a) tumor endothelial cells, leading to vascular normalization; (b) tumor cells; direct growth inhibition, immunogenic modulation, and reduction of tumor compactness allows collapsed vessels to reopen; and (c) tumor-infiltrating immune cells, increasing the frequency and function of effector immune elements while decreasing the number and function of immune suppressor cells. Collectively, these data support the clinical combination of multitargeted antiangiogenic TKIs, including but not limited to cabozantinib, sunitinib, sorafenib, pazopanib, axitinib, lapatinib, and imatinib, as well as other antiangiogenic therapies such as the anti-VEGF antibody bevacizumab, with cancer vaccines for improved treatment of solid tumors. Additional preclinical studies are warranted to determine the most appropriate schedules for combination therapies that include TKIs.
https://www.ncbi.nlm.nih.gov/m/pubmed/26005708/
Combination therapy for the treatment of cancer is becoming increasingly essential as we gain improved understanding of the complexity of cancer progression and the mechanisms by which cancer cells become resistant to single-agent therapy. Recent studies, both clinical and preclinical, have suggested that immunotherapy is a promising approach to the treatment of cancer; however, strategies to improve its clinical efficacy are still needed. A number of recent studies have indicated that antiangiogenic tyrosine kinase inhibitors (TKIs) target multiple components of the tumor microenvironment and are an ideal class of agents for synergizing with cancer immunotherapy. TKIs are well known to modulate tumor endothelial cells, leading to vascular normalization; however, these agents have also been recently shown to decrease tumor compactness and tight junctions, thereby reducing solid tumor pressure and allowing for improved perfusion of collapsed vessels and increased tumor oxygenation. In addition, some TKIs are capable of inducing immunogenic modulation, whereby tumor cells are sensitized to killing by T lymphocytes. Moreover, a number of TKIs have been shown to be involved in immune subset conditioning, increasing the frequency and function of effector immune elements, while decreasing the number and function of immune suppressor cells. The alteration of the immune landscape, direct modification of tumor cells, and improved vascular perfusion leads to improved antitumor efficacy when antiangiogenic TKIs are combined with immunotherapy. Collectively, the data presented in this review support the clinical combination of multi-targeted antiangiogenic TKIs, including but not limited to cabozantinib, sunitinib, and sorafenib, as well as to other antiangiogenic therapies, such as the anti-VEGF antibody bevacizumab, with cancer vaccines for improved treatment of solid tumors.
Keywords: cabozantinib, sunitinib, immunotherapy, combination therapy, immune subset conditioning, immunogenic modulation
Conclusions
The observations reviewed here further demonstrate that TKIs induce direct effects on tumor cells leading to their destruction via apoptotic and immune-mediated mechanisms. These observations also support the conclusions that TKIs, particularly antiangiogenic TKIs, modify the tumor microenvironment in multiple ways, including the alteration of immune cell infiltration (immune subset conditioning) leading to tumor eradication particularly when these therapies are combined with cancer immunotherapy. Unfortunately, it is common for cancer cells to become resistant to targeted therapy, particularly to small molecule inhibitors such as TKIs. It is possible that drug resistance could be avoided or overcome by combining these agents with additional therapies with which synergistic antitumor effects can be observed. In addition, the effectiveness of cancer immunotherapy can be compromised when immune cells cannot penetrate the tumor due to abnormal vasculature [44]. Data obtained using the MC38-CEA tumor model indicate that TKIs synergize with the MVA/rF-CEA/TRICOM cancer vaccine to induce changes in the tumor microenvironment resulting in improved immune cell infiltration and sustained tumor regression. The antiangiogenic TKIs described here synergize with cancer immunotherapy by targeting 3 elements of the tumor microenvironment: (a) tumor endothelial cells, leading to vascular normalization; (b) tumor cells; direct growth inhibition, immunogenic modulation, and reduction of tumor compactness allows collapsed vessels to reopen; and (c) tumor-infiltrating immune cells, increasing the frequency and function of effector immune elements while decreasing the number and function of immune suppressor cells. Collectively, these data support the clinical combination of multitargeted antiangiogenic TKIs, including but not limited to cabozantinib, sunitinib, sorafenib, pazopanib, axitinib, lapatinib, and imatinib, as well as other antiangiogenic therapies such as the anti-VEGF antibody bevacizumab, with cancer vaccines for improved treatment of solid tumors. Additional preclinical studies are warranted to determine the most appropriate schedules for combination therapies that include TKIs.
https://www.ncbi.nlm.nih.gov/m/pubmed/26005708/