Suppression of the SLC7A11/glutathione axis causes ferroptosis and apoptosis and alters the mitogen-activated protein kinase pathway in nasopharyngeal carcinoma.

SLC7A11 is a unit of the glutamate cystine antiporter Xc- system. It functions to import cystine for glutathione biosynthesis and maintains the redox balance in cells. Sorafenib inhibits the transporter activity of SLC7A11. The use of sorafenib has been approved in the treatment of multiple cancers. However, at present, our understanding of the mechanism of SLC7A11 and sorafenib in nasopharyngeal carcinoma (NPC) remains limited. We found that the expression of SLC7A11 was upregulated in NPC. A high SLC7A11 expression was associated with poor prognosis, metastasis, and an advanced T stage, which can be used as an independent prognostic indicator of NPC. In vitro, we observed that NPC cells relied on cystine for survival. Targeting SLC7A11 resulted in glutathione biosynthesis limitation, intracellular reactive oxygen species accumulation, lipid peroxides, ferroptosis, and apoptosis. Meanwhile, it altered mitogen activated protein kinase pathway, including p38 activation but ERK inhibition in NPC. This limited the proliferation of NPC cells. Sorafenib inhibited the proliferation and induced the death of NPC cells in vivo. In conclusion, SLC7A11 plays an important role in the occurrence and progression of NPC and may be a novel target for NPC treatment.

SNRPB-mediated RNA splicing drives tumor cell proliferation and stemness in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the leading malignant diseases worldwide, but therapeutic targets for HCC are lacking. Here, we characterized a significant upregulation of Small Nuclear Ribonucleoprotein Polypeptides B and B1 (SNRPB) in HCC via qRT-PCR, western blotting, tissue microarray and public database analyses. Increased SNRPB expression was positively associated with adjacent organ invasion, tumor size, serum AFP level and poor HCC patient survival. Next, we transfected SNRPB into HCC cells to construct SNRPB-overexpressing cell lines, and short hairpin RNA targeting SNRPB was used to silence SNRPB in HCC cells. Functional studies showed that SNRPB overexpression could promote HCC cell malignant proliferation and stemness maintenance. Inversely, SNRPB knockdown in HCC cells caused inverse effects. Importantly, analysis of alternative splicing by RNA sequencing revealed that SNRPB promoted the formation of AKT3-204 and LDHA-220 splice variants, which activated the Akt pathway and aerobic glycolysis in HCC cells. In conclusion, SNRPB could serve as a prognostic predictor for patients with HCC, and it promotes HCC progression by inducing metabolic reprogramming.

High levels of CCL2 or CCL4 in the tumor microenvironment predict unfavorable survival in lung adenocarcinoma.

BACKGROUND: Tumor-associated immune factors are heterogeneous and play an important role in determining outcome in cancer patients. In this study, the expression levels of immune factors in tumor tissue-conditioned media from lung squamous cell carcinoma (LUSC) and lung adenocarcinoma (LUAD) were analyzed. METHODS: LUAD and LUSC tissue specimens were collected immediately after surgery for antibody array analysis and real-time quantitative PCR. RESULTS: Higher levels of chemokines MCP1/CCL2 (21.11-fold increase) and MIP-1ß/CCL4 (19.33-fold increase) were identified in LUAD than in LUSC. Western blot and quantitative real-time PCR analyses showed higher co-expression of CCL2 and CCL4 in LUAD tissues compared to LUSC (P < 0.0001). Immunofluorescent co-staining showed a high percentage of CCL2+ /CD68+ and CCL4+ /CD68+ tumor-associated macrophages in LUAD compared to LUSC tissues, which might be responsible for the higher expression of CCL2 and CCL4 in LUAD samples. Kaplan-Meier curves showed that CCL2 overexpression in patients with LUSC was associated with beneficial overall survival (OS; P = 0.048) and progression-free survival (PFS; P = 0.012); however, LUAD patients with higher CCL2 expression had unfavorable OS (P = 6.7e-08) and PFS (P = 0.00098). Similarly, CCL4 overexpression predicted favorable PFS (P = 0.021) in patients with LUSC, but patients with high CCL4 levels in LUAD had shorter OS (P = 0.013). CONCLUSION: Our study revealed that CCL2 and CCL4 expression levels could serve as potential prognostic biomarkers and therapeutic targets for NSCLC patients.