Objectives AXL‐mediated activation of aberrant tyrosine kinase drives various oncogenic processes and facilitates an immunosuppressive microenvironment. We evaluated the anti‐tumor and anti‐metastatic activities of SKI‐G‐801, a small‐molecule inhibitor of AXL, alone and in combination with anti‐PD‐1 therapy. Methods In vitro pAXL inhibition by SKI‐G‐801 was performed in both human and mouse cancer cell lines. Immunocompetent mouse models of tumor were established to measure anti‐metastatic potential of SKI‐G‐801. Furthermore, SKI‐G‐801, anti‐PD‐1 or their combination was administered as an adjuvant or neoadjuvant in the 4T1 tumor model to assess their potential for clinical application. Results SKI‐G‐801 robustly inhibited pAXL expression in various cell lines. SKI‐G‐801 alone or in combination with anti‐PD‐1 potently inhibited metastasis in B16F10 melanoma, CT26 colon and 4T1 breast models. SKI‐G‐801 inhibited the growth of B16F10 and 4T1 tumor‐bearing mice but not immune‐deficient mice. An antibody depletion assay revealed that CD8 + T cells significantly contributed to SKI‐G‐801‐mediated survival. Anti‐PD‐1 and combination group were observed the increased CD8 + Ki67 + and effector T cells and M1 macrophage and decreased M2 macrophage, and granulocytic myeloid‐derived suppressor cell (G‐MDSC) compared to the control group. The neoadjuvant combination of SKI‐G‐801 and anti‐PD‐1 therapy achieved superior survival benefits by inducing more profound T‐cell responses in the 4T1 syngeneic mouse model. Conclusion SKI‐G‐801 significantly suppressed tumor metastasis and growth by enhancing anti‐tumor immune responses. Our results suggest that SKI‐G‐801 has the potential to overcome anti‐PD‐1 therapy resistance and allow more patients to benefit from anti‐PD‐1 therapy.
A recently developed treatment strategy for lung cancer that combines immune checkpoint inhibitors with chemotherapy has been applied as a standard treatment for lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC), and it has improved the outcomes of chemotherapy. Maintenance treatment with anti-PD-1 antibody (aPD-1) enhances the effect of immunochemical combination therapy and improves therapeutic efficacy, which contributes toward a significant improvement in patient survival rates. The AXL receptor tyrosine kinase (AXL), which is expressed in tumor cells, plays an essential role in the resistance of cancers to chemotherapy and immunotherapy, and stimulates signaling associated with epithelial-mesenchymal transition (EMT) in metastatic cancer. AXL is thus an attractive target for controlling resistance to anti-tumor therapies. In this study, we examined the effect of AXL inhibitors on immune activation and tumor growth in TC1 and C3PQ mouse tumor models, in the context of clinical immunotherapy/chemotherapy and maintenance treatment, using an aPD-1 with/without pemetrexed. To determine the optimal timing for administration of SKI-G-801, an AXL inhibitor, we investigated its anti-tumor effects based on inclusion at the immunochemotherapy and maintenance therapy stages. We also performed flow cytometry-based immune profiling of myeloid cells and lymphoid cells at different points in the treatment schedule, to investigate the immune activation and anti-tumor effects of the AXL inhibitor. The addition of SKI-G-801 to the immune checkpoint inhibitor and chemotherapy stage, as well as the maintenance therapy stage, produced the best anti-tumor results, and significant tumor growth inhibition was observed in both the TC1 and C3PQ models. Both models also exhibited increased proportion of effector memory helper T cells and increased expression of CD86+ macrophages. Especially, regulatory T cells were significantly reduced in the TC1 tumor model and there was an increase in central memory cytotoxic T cell infiltration and an increased proportion of macrophages with high CD80 expression in the C3PQ tumor model. These results suggest increased infiltration of T cells, consistent with previous studies using AXL inhibitors. It is expected that the results from this study will serve as a stepping stone for clinical research to improve the existing standard of care.
Introduction: Neoadjuvant therapy suggests the systemic treatment of cancer prior to surgical therapy. The main purpose of neoadjuvant therapy is to improve surgical outcomes in patients for whom a primary surgical approach is difficult to practice. Recently, Anti-PD-1 has been applied to neoadjuvant and adjuvant therapy, but the anti-cancer responses are not sufficient to prevent tumor recurrence. According to our previous study, a novel AXL inhibitor, SKI-G-801 strongly inhibits metastasis of syngeneic tumor with immune responses. The primary goal of this study is to overcome limitation of anti-PD-1 based neoadjuvant and adjuvant therapy with SKI-G-801. Methods: 4T1 cancer bearing mouse models were established for neoadjuvant or adjuvant treatment. Mice were treated with single anti-PD-1 (BIW), SKI-G-801 (QD) or a combination for 6 days, followed by the surgical dissection of tumor tissue in a subcutaneous xenograft model. In five mice per group, their survival rates were monitored for 50 days. We used flow cytometry and immunohistochemistry for comprehensive immune profiling and tumor-infiltrating lymphocytes (TILs) from three mice per group surgically removed tumor tissues. Three tumors per group were stained, and CD3-positive cells per unit area (mm2) were analyzed using Vectra Polaris. Results: According to results, the median survival of control group (only surgical operation without treatment) was 16 days (N=5), whereas, the longest survival group was neoadjuvant-combination (median survival = 37 days). Two out of five mice were survived until end of experiment (D-50). Most of the groups had similar outcomes excluding neoadjuvant-combination group. The median survival of adjuvant-anti-PD-1 group was 30 days, and adjuvant-SKI-G-801 and neoadjuvant-anti-PD-1 group were 25 days. The Neoadjuvant-SKI-G-801 was recorded 23.5 days. Statistically, survival rate of neoadjuvant-combination therapy was significantly higher than of neoadjuvant-anti-PD-1 and neoadjuvant-SKI-G-801 (log-rank test, p <0.01).The reason for neoadjuvant therapy is to improve immune responses before surgical operation. We investigated the effects of SKI-G-801 or anti-PD-1 alone and combination therapy on neoadjuvant treatment in the tumor microenvironment. IHC and flow cytometry were performed to elucidate tumor infiltrating immune cell populations with the tumor obtained by surgery. In IHC result, CD3+ cells population was significantly increased in SKI-G-801 alone and combination of neoadjuvant therapy compared to control group (p<0.05, p < 0.001, respectively), however, anti-PD-1 group was not significant. IFN-γ+ Tc cells, CD3+CD44+ memory Tc, and PD-1+Tc cells were significantly infiltrated into the tumor in the combination of neoadjuvant therapy (p < 0.01). Conclusion: This study confirmed that a potential combination with aPD-1 and SKI-G-801 applies to neoadjuvant therapy, as evidenced by increased T cell infiltration and function. Our findings provide a rationale for further clinical investigations. Keywords: Axl inhibitor, Neoadjuvant therapy, Adjuvant therapy, Immunotherapy, Anti-PD-1 Citation Format: Ha Ni Jo, Wongeun Lee, Chun-Bong Synn, Hee Kyu Lee, Jae-Hwan Kim, Yeongseon Byeon, Sung Eun Kim, Ji Min Lee, Do Hee Kim, Jung-Ho Kim, Beung-Chul Ahn, Min Hee Hong, Hye Ryun Kim, Kyoung-Ho Pyo, Byoung Chul Cho. Neoadjuvant and adjuvant anti-PD-1 based combination immunotherapy with a novel AXL inhibitor, SKI-G-801 in syngeneic tumor model: A combined analysis of immune profiling [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5189.
Introduction: Aberrant AXL expression plays a critical role in cancer cell migration, metastasis and drug resistance. Researchers have revealed that AXL signaling is also over expressed on cells associated with tumor microenvironment. These findings highlight AXL as an attractive drug candidate for targeting tumor evasion and metastasis. Here we present SKI-G-801, a small molecule inhibitor that targets phosphorylation of AXL (IC50 = 20 nM) and its downstream signals. Methods: Inhibitory effects of SKI-G-801 on cancer viability (MTT and colony formation assay), invasion and migration (trans-well invasion assay) were examined in AXL high-expressing lung cancer cells in vitro. LLC2 lung and 4T1 breast cancer bearing mouse models were established. in addition, C57BL/6 mice were injected intravenously with B16F10 melanoma cells to establish lung metastasis model. Mice were administrated with 30 mg/kg of SKI-G-801 orally before (metastasis model) or after (syngeneic model) tumor injection. To elucidate the involvement of AXL inhibitor on tumor microenvironment, the population of T cells and myeloid cells was analyzed by flow cytometry from the LLC2 tumor. Results: Treatment of SKI-G-801 showed strong inhibition of cancer migration and invasion, when its direct killing effect on cancer cells was modest. These results were reproduced in vivo test that pretreatment of SKI-G-801 significantly reduced metastatic burden in B16F10 model (p < 0.05). LLC2 and 4T1 tumors were decreased in SKI-G-801 treatment group (p < 0.05), but not in anthemic nude mice. CD3+CD8+ T cell population and memory Tc cells were increased in SKI- G-801 treatment group (p < 0.05). Especially, granzyme B+ Tc and gp70+ tumor specific Tc were increased (p < 0.05). SKI-G-801 increase the helper T cell population; CD3+CD4+ (p < 0.05), and CD44+ memory Th cells (p < 0.01). Conclusion: SKI-G-801 demonstrates great potential in anti-cancer activity though immune responses. The anti-cancer effects lead to a reversal of the metastatic phenotype in animal model. Our results suggest that SKI-G-801 is a promising drug for prevention against metastatic cancer. Citation Format: Chun-Feng Xin, Sung Eun Kim, Kyoung-Ho Pyo, Ha Ni Jo, Jae Seok Cho, Jae Hwan Kim, Wongeun Lee, Hee Kyu Lee, Jung-Ho Kim, Ho-Juhn Song, Jong Sung Koh, Byoung Chul Cho. SKI-G-801, an AXL kinase inhibitor, blocks metastasis and induces anti-tumor immune responses in various syngeneic cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2010.
Background: AXL has been identified to play multiple roles in the tumor microenvironment including the promotion of epithelial-mesenchymal transition and immune evasion. SKI-G-801, a small molecule inhibitor targeting phosphorylation of AXL, presented strong inhibition of cancer migration and invasion. Anti-PD-1(αPD-1) combined with paclitaxel(Pac)/carboplatin(Carbo) and pemetrexed(Pem)/cisplatin(Cis) are standard therapy in non-squamous and squamous lung cancer patients, respectively. Herein, we present that adding AXL inhibition with SKI-G-801 on αPD-1 plus chemotherapy suppressed tumor growth and improved overall survival and also enhanced anti-tumor T cell immunity in both non-squamous and squamous lung cancer models. Methods: C3PQ squamous and TC-1 non-squamous lung cancer bearing mouse models were established. In C3PQ squamous model, mice were treated with 2 cycles of induction Carbo + Pac + αPD-1 and 13 cycles of maintenance with αPD-1. In TC-1 non-squamous model, mice were treated with 3 cycles of induction with Cis + Pem + αPD-1 and 14 cycles of maintenance therapy. Both models included the groups of SKI-G-801 treatment from induction therapy and/or maintenance therapy. The tumor growth and survival were monitored for 60 days in both models. The tumor infiltrated lymphocytes were analyzed by flow cytometry. Results: In TC-1 non-squamous model, upfront addition of SKI-G-801 on αPD-1 plus Pem/Cis chemotherapy followed by αPD-1 and Pem maintenance showed the superior overall survival to the others (vs. αPD-1+ Pem/Cis and αPD-1 + Pem maintenance; p<0.001, vs. αPD-1 + Pem/Cis and αPD-1 + Pem + SKI-G-801 maintenance; p<0.01, vs. αPD-1 + Pem/Cis and SKI-G-801 maintenance; p<0.01). In C3PQ squamous model, upfront addition of SKI-G-801 on αPD-1 plus Pac/Carbo followed by αPD-1 prolonged the overall survival compared the others (vs. αPD-1+Pac/Carbo and αPD-1 maintenance; p<0.05, vs. αPD-1 + Pac/Carbo and αPD-1+ SKI-G-801 maintenance; p<0.05, vs. αPD-1 + Pac/Carbo + SKI-G-801 maintenance; n.s.). In line with survival outcomes, upfront SKI-G-801 on αPD-1 combined with chemotherapy showed the strong tumor growth inhibition compared to the others. Especially, effector memory T cells (CD3+CD4+CD44+CD107-) and IFN-γ secretion level of CD8+ T cells were significantly increased in SKI-G-801 treated groups in C3PQ model (p<0.05). Conclusion: Incorporation of SKI-G-801, a novel AXL inhibitor, with αPD-1 combined with chemotherapy significantly improved overall survival and anti-tumor activity in both non-squamous and squamous lung cancer model through enhancing cytotoxicity of CD8+ T cells and memory CD4+ T cells. These findings provide mechanistic insight into the activity of SKI-G-801 combined with standard therapy and support its clinical development in metastatic NSCLC as first line therapy. Citation Format: Kyoung-Ho Pyo, Wongeun Lee, Hee Kyu Lee, Dong Kwon Kim, Ha Ni Jo, Chun-Bong Synn, Jae Hwan Kim, Yeongseon Byeon, Young Seob Kim, Beung-Chul Ahn, Min Hee Hong, Sun Min Lim, Byoung Chul Cho, Hye Ryun Kim. Incorporation of SKI-G-801, novel AXL inhibitor, with anti-PD-1 inhibitor plus chemotherapy improved anti-tumor activity and survival outcome via enhancing anti-tumor T cell immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1471.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.