Optimized CAR-T therapy based on spatiotemporal changes and chemotactic mechanisms of MDSCs induced by hypofractionated radiotherapy.

Poor intratumoral infiltration is the major challenge for chimeric antigen receptor (CAR)-T cell therapy in solid tumors. Hypofractionated radiotherapy (HFRT) has been reported to induce immune cell infiltration and reshape the tumor immune microenvironment. Here, we showed that HFRT (5 × 5 Gy) mediated an early accumulation of intratumoral myeloid-derived suppressor cells (MDSCs) and decreased infiltration of T cells in the tumor microenvironment (TME) of immunocompetent mice bearing triple-negative breast cancer (TNBC) or colon cancer, which was further confirmed in tumors from patients. RNA sequencing (RNA-seq) and cytokine profiling analysis revealed that HFRT induced the activation and proliferation of tumor-infiltrated MDSCs, which was mediated by the interactions of multiple chemokines and chemokine receptors. Further investigation showed that when combined with HFRT, CXCR2 blockade significantly inhibited MDSCs trafficking to tumors and effectively enhanced the intratumoral infiltration and treatment efficacy of CAR-T cells. Our study demonstrates that MDSCs blockade combined with HFRT is promising for CAR-T cell therapy optimization in solid tumors.

MNK: A Novel Promising Target for Cancer Immunotherapy.

Cancer immunotherapy has demonstrated remarkable success in the treatment of multiple advanced malignancies, especially approaches to target the immune checkpoint. Nonetheless, the limited response rate remains a barrier to broader application. Identifying other ways to extend the beneficiaries to a large extent is needed. Emerging evidence has shown that mitogen-activated protein kinase-interacting kinases (MNKs) could be regarded as a novel, attractive target for cancer immunotherapy that is closely correlated with cancer biology and therapies. A comprehensive understanding of the role and mechanism of MNKs in cancer will shed light on the discovery of novel therapeutic strategies for cancer treatment. In this review, we outlined the structure of MNKs, their function and expression, and how MNKs affect tumor progression and elucidated the evidence supporting MNKs as a new promising treatment modality in human cancers.

Targeting sphingosine 1-phosphate receptor 3 inhibits T-cell exhaustion and regulates recruitment of proinflammatory macrophages to improve antitumor efficacy of CAR-T cells against solid tumor.

BACKGROUNDS: Chimeric antigen receptor (CAR)-modified T cells (CAR-T) are limited in solid tumors due to the hostile tumor microenvironment (TME). Combination therapy could be a promising approach to overcome this obstacle. Recent studies have shown that sphingosine 1-phosphate receptor (S1PR)3 has tremendous potential in regulating the immune environment. However, the functional significance of S1PR3 in T-cell-based immunotherapies and the molecular mechanisms have not been fully understood. METHODS: Here, we studied the combination of EpCAM-specific CAR T-cell therapy with pharmacological blockade of S1PR3 against solid tumor. We have applied RNA sequencing, flow cytometry, ELISA, cellular/molecular immunological technology, and mouse models of solid cancers. RESULTS: Our study provided evidence that S1PR3 high expression is positively associated with resistance to programmed cell death protein-1 (PD-1)-based immunotherapy and increased T-cell exhaustion. In addition, pharmacological inhibition of S1PR3 improves the efficacy of anti-PD-1 therapy. Next, we explored the possible combination of S1PR3 antagonist with murine EpCAM-targeted CAR-T cells in immunocompetent mouse models of breast cancer and colon cancer. The results indicated that the S1PR3 antagonist could significantly enhance the efficacy of murine EpCAM CAR-T cells in vitro and in vivo. Mechanistically, the S1PR3 antagonist improved CAR-T cell activation, regulated the central memory phenotype, and reduced CAR-T cell exhaustion in vitro. Targeting S1PR3 was shown to remodel the TME through the recruitment of proinflammatory macrophages by promoting macrophage activation and proinflammatory phenotype polarization, resulting in improved CAR-T cell infiltration and amplified recruitment of CD8+T cells. CONCLUSIONS: This work demonstrated targeting S1PR3 could increase the antitumor activities of CAR-T cell therapy at least partially by inhibiting T-cell exhaustion and remodeling the TME through the recruitment of proinflammatory macrophages. These findings provided additional rationale for combining S1PR3 inhibitor with CAR-T cells for the treatment of solid tumor.

Neurotoxicity of Tumor Immunotherapy: The Emergence of Clinical Attention.

Tumor immunotherapy brings substantial and long-term clinical benefits that can even cure tumors. However, the accumulation of evidence suggests that immunotherapy also induces severe and complex neurologic immune-related adverse events (ir-AEs) and even leads to immunotherapy-related death, which arouses the concern of clinicians. The timely and accurate identification of neurotoxicity helps clinicians detect and treat these complications early, thereby enhancing treatment efficiency and improving the prognosis of patients. At present, the mechanism of neurotoxicity caused by immunotherapy has not been completely elucidated. This paper mainly reviews the clinical features, pathogenesis, and therapeutic strategies of neurologic ir-AEs.

The role of angiogenesis in malignant pleural effusion: from basic research to clinical application.

Malignant pleural effusion (MPE) is associated with advanced stages of various malignant diseases, especially lung cancer, and is a poor prognostic indicator in these patients. However, the management of MPE remains palliative. A better understanding of the pathogenesis of MPE may lead to the development of new and more effective therapeutic options. Here, we shed light on recent advances in the mechanisms of MPE formation and provide an overview of current targeted therapies for the vascular endothelial growth factor pathway. We also retrospectively enrolled 19 patients with lung adenocarcinoma from the West China Hospital to analyze the efficacy of bevacizumab for MPE using different routes of administration.

A PD-L1-targeting chimeric switch receptor enhances efficacy of CAR-T cell for pleural and peritoneal metastasis.

Pleural and peritoneal metastasis accompanied by malignant pleural effusion (MPE) or malignant ascites (MA) is frequent in patients with advanced solid tumors that originate from the lung, breast, gastrointestinal tract and ovary. Regional delivery of CAR-T cells represents a new strategy to control tumor dissemination in serous cavities. However, malignant effusions constitute an immune-suppressive environment that potentially induces CAR-T cell dysfunction. Here, we demonstrated that the anti-tumor cytotoxicity of conventional 2nd-generation CAR-T cells was significantly inhibited by both the cellular and non-cellular components of MPE/MA, which was primarily attributed to impaired CAR-T cell proliferation and cytokine production in MPE/MA environment. Interestingly, we found that PD-L1 was widely expressed on freshly-isolated MPE/MA cells. Based on this feature, a novel PD-L1-targeting chimeric switch receptor (PD-L1.BB CSR) was designed, which can bind to PD-L1, switching the inhibitory signal into an additional 4-1BB signal. When co-expressed with a 2nd-generation CAR, PD-L1.BB CSR-modified CAR-T cells displayed superior fitness and enhanced functions in both culture medium and MPE/MA environment, causing rapid and durable eradication of pleural and peritoneal metastatic tumors in xenograft models. Further investigations revealed elevated expressions of T-cell activation, proliferation, and cytotoxicity-related genes, and we confirmed that PD-L1 scFv and 4-1BB intracellular domain, the two important components of PD-L1.BB CSR, were both necessary for the functional improvements of CAR-T cells. Overall, our study shed light on the clinical application of PD-L1.BB CSR-modified dual-targeting CAR-T cells. Based on this study, a phase I clinical trial was initiated in patients with pleural or peritoneal metastasis (NCT04684459).

Myeloid-derived suppressor cells as immunosuppressive regulators and therapeutic targets in cancer.

Myeloid-derived suppressor cells (MDSCs) are a heterogenic population of immature myeloid cells with immunosuppressive effects, which undergo massive expansion during tumor progression. These cells not only support immune escape directly but also promote tumor invasion via various non-immunological activities. Besides, this group of cells are proved to impair the efficiency of current antitumor strategies such as chemotherapy, radiotherapy, and immunotherapy. Therefore, MDSCs are considered as potential therapeutic targets for cancer therapy. Treatment strategies targeting MDSCs have shown promising outcomes in both preclinical studies and clinical trials when administrated alone, or in combination with other anticancer therapies. In this review, we shed new light on recent advances in the biological characteristics and immunosuppressive functions of MDSCs. We also hope to propose an overview of current MDSCs-targeting therapies so as to provide new ideas for cancer treatment.

KRAS G12D mutation predicts lower TMB and drives immune suppression in lung adenocarcinoma.

OBJECTIVES: The efficacy of anti- programmed cell death 1 (PD-1)/PD-1 ligand (PD-L1) immune checkpoint inhibitors remains controversial in patients with KRAS mutation. In addition, whether and how KRAS gene and its mutant subtypes might influence immunity has not been clarified yet. Here we examine some important biomarkers for the efficacy of immunotherapy in specific KRAS subtypes. MATERIALS AND METHODS: We conducted a bioinformatics analysis on somatic mutations data, transcriptome sequencing data and proteomic data from The Cancer Genome Atlas (TCGA) database. CIBERSORT was used to provide an estimation of the abundances of immune cells using gene expression data. RESULTS: From a cohort of 567 patients with lung adenocarcinoma (LUAD) based on TCGA, the overall mutation rate of KRAS was 26.29 %, including KRAS/TP53 co-mutation rate of 9.7 %. We observed increased Tumor mutation burden (TMB) in KRAS mutant group compared with wild type, while no difference in PD-L1 expression and immune cell infiltration. More importantly, TP53 and KRAS/TP53 co-mutation group not only significantly increased tumor mutation burden, but also had higher PD-L1 protein level and immune cell infiltration. We further focused on influence of KRAS mutant subtype on immune biomarker. The most prevalent mutant subtype of KRAS in lung adenocarcinoma was G12C(9.88 %,56/567), followed by G12 V(5.82 %,33/567), G12D(3.00 %,17/567), G12A(3.00 %,17/567), respectively. Among them, G12D mutation appeared to be a special mutant subtype with an obviously lower TMB. This low mutation load was more significant when co-mutation with TP53. Besides, our results also revealed significantly decreased expressions of PD-L1 protein level and immune cell infiltration (activated CD4 memory T cell, helper T cell, M1 macrophage and NK cell) in KRAS G12D/TP53 mutant group. CONCLUSION: KRAS G12D/TP53 co-mutation drives immune suppression and might be a negative predictive biomarker for anti-PD-1/PD-L1 immune checkpoint inhibitors in patients with lung adenocarcinoma.

Potential lung attack and lethality generated by EpCAM-specific CAR-T cells in immunocompetent mouse models.

The tumoricidal efficiency of human CAR-T cells is generally evaluated using immune-deficient mouse models; however, due to their immune-incompetency and the species-specific reactivity of a target antigen, these models are problematic to imitate CAR-T-induced adverse effects in the clinic. Epithelial cell adhesion molecule (EpCAM) is a tumor-associated antigen overtly presented on the cell surface of various carcinomas, making it an attractive target for CAR-T therapy. Here, we developed an anti-mouse EpCAM CAR to evaluate its safety and efficacy in immunocompetent mouse models. As previously reported for their human equivalents, murine EpCAM CAR-T cells exhibit promising anti-tumor efficacy in vitro and in vivo. However, after CAR-T infusion, various dose-depended toxicities including body weight loss, cytokine-release syndrome (CRS), and death were observed in both tumor-bearing and tumor-free mice. Pathological examination revealed unexpected and severe pulmonary immunopathology due to basal EpCAM expression in normal lung. While our study validates EpCAM CAR-T's potent anti-tumor efficacy, it also reveals that EpCAM CAR-T cells used for the treatment of solid tumors may cause lethal toxicity and should, therefore, be evaluated in patients with caution.

Trends in the incidence rate of lung cancer by histological type and gender in Sichuan, China, 1995-2015: A single-center retrospective study.

BACKGROUND: In recent years, lung cancer incidence has been increasing; however the impact of different histological types of lung cancer is not yet clear. METHODS: Trends in the lung cancer incidence rate by histological type were examined based on data of 36 658 primary lung cancer patients from West China Hospital between 1995 and 2015. RESULTS: The most common histological type of lung cancer in our hospital was adenocarcinoma (ADC) in both genders, followed by squamous cell carcinoma (SQCC), and small cell carcinoma (SCLC), which is consistent with general worldwide trends. The proportion of young patients with SCLC showed a downward trend. In the overall population with lung cancer, the number of elderly patients with lung cancer increased significantly, while the proportion of elderly patients increased gradually. The mean age at diagnosis also increased. The number of women with ADC increased sharply in recent years, especially in young patients, and the incidence rate in women is now greater than in men. CONCLUSION: Significant increases in the number of patients with ADC and the rate of lung cancer in women over recent years were observed, indicating that research on the pathogenesis of disease in these patients is urgent.