Down-regulated expression of CDK5RAP3 and UFM1 suggests a poor prognosis in gastric cancer patients.

Purpose: The relationship between the CDK5RAP3 and UFM1 expression and the prolonged outcomes of patients who underwent gastric cancer (GC) surgery was investigated. Methods: Single-sample gene set enrichment analysis (ssGSEA), unsupervised clustering and other methods were used to verify the relationship between CDK5RAP3 and UFM1 in GC through public databases. Additionally, CDK5RAP3 and UFM1 expression in cancerous and paracancerous tissues of GC was analysed in the context of patient prognosis. Results: CDK5RAP3 and UFM1 expression was downregulated synchronously, the interaction was observed between the two proteins, and UFM1 and CDK5RAP3 expression was found to be inversely associated to AKT pathway activation. Prognostic analysis showed that the prognosis is poorer for low CDK5RAP3 and UFM1 patients, than for high CDK5RAP3 and/or UFM1 (p<0.001) patients, and this expression pattern was an independent predictor for overall survival of GC. Coexpression of CDK5RAP3 and UFM1 combined with TNM staging can improve the accuracy of prognosis prediction for patients (p <0.001). Conclusions: It is confirmed in our findings that a combination of CDK5RAP3 and UFM1 can produce a more precise prediction model for GC patients' survival.

m6A methylation mediates LHPP acetylation as a tumour aerobic glycolysis suppressor to improve the prognosis of gastric cancer.

LHPP, a histidine phosphatase, has been implicated in tumour progression. However, its role, underlying mechanisms, and prognostic significance in human gastric cancer (GC) are elusive. Here, we obtained GC tissues and corresponding normal tissues from 48 patients and identified LHPP as a downregulated gene via RNA-seq. qRT-PCR and western blotting were applied to examine LHPP levels in normal and GC tissues. The prognostic value of LHPP was elucidated using tissue microarray and IHC analyses in two independent GC cohorts. The functional roles and mechanistic insights of LHPP in GC growth and metastasis were evaluated in vitro and in vivo. The results showed that LHPP expression was significantly decreased in GC tissues at both the mRNA and protein levels. Multivariate Cox regression analysis revealed that LHPP was an independent prognostic factor and effective predictor in patients with GC. The low expression of LHPP was significantly related to the poor prognosis and chemotherapy sensitivity of gastric cancer patients. Moreover, elevated LHPP expression effectively suppressed GC growth and metastasis in vitro and in vivo. Mechanistically, the m6A modification of LHPP mRNA by METTL14 represses its expression; LHPP inhibits the phosphorylation of GSK3b through acetylation and mediates HIF1A to inhibit glycolysis, proliferation, invasion and metastasis of gastric cancer cells. Together, our findings suggest that LHPP is regulated by m6A methylation and regulates the metabolism of GC by changing the acetylation level. Thus, LHPP is a potential predictive biomarker and therapeutic target for GC.

An immune checkpoint score system for prognostic evaluation and adjuvant chemotherapy selection in gastric cancer.

Immunosuppressive molecules are extremely valuable prognostic biomarkers across different cancer types. However, the diversity of different immunosuppressive molecules makes it very difficult to accurately predict clinical outcomes based only on a single immunosuppressive molecule. Here, we establish a comprehensive immune scoring system (ISSGC) based on 6 immunosuppressive ligands (NECTIN2, CEACAM1, HMGB1, SIGLEC6, CD44, and CD155) using the LASSO method to improve prognostic accuracy and provide an additional selection strategy for adjuvant chemotherapy of gastric cancer (GC). The results show that ISSGC is an independent prognostic factor and a supplement of TNM stage for GC patients, and it can improve their prognosis prediction accuracy; in addition, it can distinguish GC patients with better prognosis from those with high prognostic nutritional index score; furthermore, ISSGC can also be used as a tool to select GC patients who would benefit from adjuvant chemotherapy independent of their TNM stages, MSI status and EBV status.

CDK5RAP3 inhibits angiogenesis in gastric neuroendocrine carcinoma by modulating AKT/HIF-1α/VEGFA signaling.

BACKGROUND: Angiogenesis plays critical roles in the progression and metastasis of malignant tumors. Gastric neuroendocrine carcinoma is an uncommon stomach cancer that is rich in blood vessels and exhibits highly malignant biological behavior with a poor prognosis. The role of CDK5RAP3 in GNEC has not been reported to date. METHODS: Immunohistochemistry was used to assess the expression of CDK5RAP3 in GNEC tissues and adjacent non-tumor tissues. Cell lines with stable overexpression or knockdown of CDK5RAP3 were constructed using lentiviral transfection. Wound-healing assays, invasion and metastasis assays, tube formation assays, and tumor xenograft transplantation assays were performed to evaluate the effect of CDK5RAP3 on GNEC angiogenesis in vitro and in vivo. Real-time PCR, ELISA, western blot analysis, and confocal-immunofluorescence staining were used to explore the molecular mechanism of CDK5RAP3's effect on angiogenesis. RESULTS: Compared with their respective adjacent non-tumor tissues, protein levels of CDK5RAP3 were significantly decreased in GNEC tissues. Furthermore, low expression of CDK5RAP3 was correlated with more advanced TNM stage, increased tumor microvessel density, and poor prognosis. Functionally, we found that GNEC cells with CDK5RAP3 knockdown promoted human umbilical vein endothelial cells migration and tube formation via activation of AKT/HIF-1α/VEGFA signaling, resulting in increased levels of VEGFA in GNEC cell supernatant. In addition, CDK5RAP3 overexpression in GNEC cells caused the opposing effect. Consistent with these results, nude mouse tumorigenicity assays showed that CDK5RAP3 expression downregulated angiogenesis in vivo. Lastly, patients with low CDK5RAP3 expression and high VEGFA expression exhibited the worst prognosis. CONCLUSIONS: This study demonstrated that CDK5RAP3 inhibits angiogenesis by downregulating AKT/HIF-1α/VEGFA signaling in GNEC and improves patient prognosis, suggesting that CDK5RAP3 could be a potential therapeutic target for GNEC.

UFM1 suppresses invasive activities of gastric cancer cells by attenuating the expres7sion of PDK1 through PI3K/AKT signaling.

BACKGROUND: UFM1 has been found to be involved in the regulation of tumor development. This study aims to clarify the role and potential molecular mechanisms of UFM1 in the invasion and metastasis of gastric cancer. METHODS: Expression of UFM1 in gastric tumor and paired adjacent noncancerous tissues from 437 patients was analyzed by Western blotting, immunohistochemistry, and realtime PCR. Its correlation with the clinicopathological characteristics and prognosis of gastric cancer patients was analyzed. The effects of UFM1 on the invasion and migration of gastric cancer cells were determined by the wound and trans-well assays, and the effect of UFM1 on subcutaneous tumor formation was verified in nude mice. The potential downstream targets of UFM1 and related molecular mechanisms were clarified by the human protein kinase assay and co-immunoprecipitation technique. RESULTS: Compared with the corresponding adjacent tissues, the transcription level and protein expression level of UFM1 in gastric cancer tissues were significantly downregulated (P < 0.05). The 5-year survival rate of gastric cancer patients with low UFM1 expression was significantly lower than the patients with high UFM1 expression (42.1% vs 63.0%, P < 0.05). The invasion and migration abilities of gastric cancer cells with stable UFM1 overexpression were significantly decreased, and the gastric cancer cells with UFM1 stable knockdown showed the opposite results; similar results were also obtained in the nude mouse model. Further studies have revealed that UFM1 could increase the ubiquitination level of PDK1 and decrease the expression of PDK1 at protein level, thereby inhibiting the phosphorylation level of AKT at Ser473. Additionally, the effect of UFM1 on gastric cancer cell function is dependent on the expression of PDK1. The expression level of UFM1 can improve the poor prognosis of PDK1 in patients with gastric cancer. CONCLUSION: UFM1 suppresses the invasion and metastasis of gastric cancer by increasing the ubiquitination of PDK1 through negatively regulating PI3K/AKT signaling.