Significant developments in cancer treatment have been made since the advent of immune therapies. However, there are still some patients with malignant tumors who do not benefit from immunotherapy. Tumors without immunogenicity are called “cold” tumors which are unresponsive to immunotherapy, and the opposite are “hot” tumors. Immune suppressive cells (ISCs) refer to cells which can inhibit the immune response such as tumor‐associated macrophages (TAMs), myeloid‐derived suppressor cells (MDSCs), regulatory T (Treg) cells and so on. The more ISCs infiltrated, the weaker the immunogenicity of the tumor, showing the characteristics of “cold” tumor. The dysfunction of ISCs in the tumor microenvironment (TME) may play essential roles in insensitive therapeutic reaction. Previous studies have found that epigenetic mechanisms play an important role in the regulation of ISCs. Regulating ISCs may be a new approach to transforming “cold” tumors into “hot” tumors. Here, we focused on the function of ISCs in the TME and discussed how epigenetics is involved in regulating ISCs. In addition, we summarized the mechanisms by which the epigenetic drugs convert immunotherapy‐insensitive tumors into immunotherapy‐sensitive tumors which would be an innovative tendency for future immunotherapy in “cold” tumor.

RAB7A (RAS-related in Brain 7A) is an important member of the RAS oncogene family. However, the correlation between RAB7A and the development and immune infiltration of hepatocellular carcinoma (HCC) has rarely been studied. Here, we studied the role of RAB7A in HCC through bioinformatics analysis, real-world cohort validation, and in vitro experimental exploration. The RAB7A expression level was analyzed through TCGA, HPA and TISIDB databases. TIMER and TISCH were used to analyze the correlation between RAB7A and tumor immune microenvironment. The expression of RAB7A was detected through real-time PCR and western blotting. The cell proliferation was detected by EdU and CCK8. Wound-healing and transwell assays were used to test the invasion and migration ability. Cell cycle distribution and reactive oxygen species (ROS) content were analyzed by flow cytometry. Identification of epithelial-mesenchymal transition (EMT) was performed by immunofluorescence double staining. Immunohistochemistry (IHC) was used to evaluate the correlation between RAB7A and immune checkpoints. RAB7A is upregulated in most of the tumor types, and the upregulation of RAB7A is associated with a poorer prognosis in many cancers. The results showed that RAB7A was significantly positively correlated with the infiltration of macrophages and cancer-associated fibroblasts (CAFs), but negatively correlated with M2-type macrophages in most tumors. The single-cell atlas also revealed the distribution and proportion of RAB7A in immune cells of HCC. The in vitro experiments suggested that RAB7A was increased in HCC tissue and cell lines. The knockdown of RAB7A inhibited the activation of the PIK3CA-AKT pathway and suppressed the expression of CDK4, CDK6 and CCNA2. Knockdown of RAB7A induced G0/G1 arrest and ROS accumulation in HCC. In addition, overexpression of RAB7A enhanced migration and invasion by inducing EMT. The real-world cohort showed that the expression level of RAB7A was positively correlated with the expression levels of TGFBR1 and PD-L1. RAB7A may serve as a potential tumor prognostic and immune infiltration-related biomarker, predicting immunotherapy efficacy in certain cancer types, especially in HCC. Besides, RAB7A was a multi-pathway target involved in the malignant progression of HCC.

Background: Nonalcoholic steatohepatitis (NASH)-driven hepatocellular carcinoma (HCC) is becoming a major health-related problem. The exploration of NASH-related prognostic biomarkers and therapeutic targets is necessary. Methods: Data were downloaded from the GEO database. The “glmnet” package was used to identify differentially expressed genes (DEGs). The prognostic model was constructed by the univariate Cox and LASSO regression analyses. Validation of the expression and prognosis by immunohistochemistry (IHC) in vitro. Drug sensitivity and immune cell infiltration were analyzed by CTR-DB and ImmuCellAI. Results: We constructed a prognostic model that identified the NASH-related gene set (DLAT, IDH3B, and MAP3K4), which was validated in a real-world cohort. Next, seven prognostic transcription factors (TFs) were identified. The prognostic ceRNA network included three mRNAs, four miRNAs, and seven lncRNAs. Finally, we found that the gene set was associated with drug response which was validated in six clinical trial cohorts. Moreover, the expression level of the gene set was inversely correlated with CD8 T cell infiltration in HCC. Conclusions: We established a NASH-related prognostic model. Upstream transcriptome analysis and the ceRNA network provided clues for mechanism exploration. The mutant profile, drug sensitivity, and immune infiltration analysis further guided precise diagnosis and treatment strategies.

Background: Immunotherapy is effective only in limited patients. It is urgent to discover a novel biomarker to predict immune cells infiltration status and immunotherapy response of different cancers. CLSPN has been reported to play a pivotal role in various biological processes. However, a comprehensive analysis of CLSPN in cancers has not been conducted. Methods: To show the whole picture of CLSPN in cancers, a pan-cancer analysis was conducted in 9125 tumor samples across 33 cancer types by integrating transcriptomic, epigenomic and pharmacogenomics data. Moreover, the role of CLSPN in cancer was validated by CCK-8, EDU, colony formation and flow cytometry in vitro and tumor cell derived xenograft model in vivo. Results: CLSPN expression was generally upregulated in most cancer types and was significantly associated with prognosis in different tumor samples. Moreover, elevated CLSPN expression was closely correlated with immune cells infiltration, TMB (tumor mutational burden), MSI (microsatellite instability), MMR (mismatch repair), DNA methylation and stemness score across 33 cancer types. Enrichment analysis of functional genes revealed that CLSPN participated in the regulation of numerous signaling pathways involved in cell cycle and inflammatory response. The expression of CLSPN in LUAD patients were further analyzed at the single-cell level. Knockdown CLSPN significantly inhibited cancer cell proliferation and cell cycle related cyclin-dependent kinase (CDK) family and Cyclin family expression in LUAD (lung adenocarcinoma) both in vitro and in vivo experiments. Finally, we conducted structure-based virtual screening by modelling the structure of CHK1 kinase domain and Claspin phosphopeptide complex. The top five hit compounds were screened and validated by molecular docking and Connectivity Map (CMap) analysis. Conclusion: Our multi-omics analysis offers a systematic understanding of the roles of CLSPN in pan-cancer and provides a potential target for future cancer treatment.

Background: Immunotherapy is a promising anti-cancer strategy in hepatocellular carcinoma (HCC). However, a limited number of patients can benefit from it. There are currently no reliable biomarkers available to find the potential beneficiaries. Methylcytosine (m⁵C) is crucial in HCC, but its role in forecasting clinical responses to immunotherapy has not been fully clarified.Methods: In this study, we analyzed 371 HCC patients from The Cancer Genome Atlas (TCGA) database and investigated the expression of 18 m⁵C regulators. We selected 6 differentially expressed genes (DEGs) to construct a prognostic risk model as well as 2 m⁵C-related diagnostic models.Results: The 1-, 3-, and 5-year area under the curve (AUC) of m⁵C scores for the overall survival (OS) was 0.781/0.762/0.711, indicating the m⁵C score system had an ideal distinction of prognostic prediction for HCC. The survival analysis showed that patients with high-risk scores present a worse prognosis than the patients with low-risk scores (p< 0.0001). We got consistent results in 6 public cohorts and validated them in Xiangya real-world cohort by quantitative real-time PCR and immunohistochemical (IHC) assays. The high-m⁵C score group was predicted to be in an immune evasion state and showed low sensitivity to immunotherapy, but high sensitivity to chemotherapy and potential targeted drugs and agents, such as sepantronium bromide (YM-155), axitinib, vinblastine and docetaxel. Meanwhile, we also constructed two diagnostic models to distinguish HCC tumors from normal liver tissues or liver cirrhosis.Conclusion: In conclusion, our study helps to early screen HCC patients and select patients who can benefit from immunotherapy. Step forwardly, for the less likely beneficiaries, this study provides them with new potential targeted drugs and agents for choice to improve their prognosis.