Upregulation of KLHL17 promotes the proliferation and migration of non-small cell lung cancer by activating the Ras/MAPK signaling pathway.

Analysis of the Gene Expression Profiling Interactive Analysis (GEPIA) database revealed that Kelch-like 17 (KLHL17) is overexpressed in non-small cell lung cancer (NSCLC) including adenocarcinoma (ADC) and squamous cell carcinoma (SCC). We therefore explored the role of KLHL17 in the development and progression of NSCLC. Immunohistochemistry and western blotting showed that KLHL17 expression was significantly higher in the tumor tissues from 173 patients with NSCLC, compared with the corresponding non-neoplastic tissue. In addition, upregulated KLHL17 expression was positively correlated with tumor size, lymph node metastasis and tumor node metastasis (TNM) stage, and affected the overall survival (OS) of patients with NSCLC. Consistent with clinical samples, in vitro studies demonstrated that KLHL17 expression was higher in various cell lines of NSCLC (A549, H1299, H460 and SK cells) as compared to normal human bronchial epithelial cells (HBE cells). Overexpression of KLHL17 in the cell lines of NSCLC with KLHL17-Flag plasmid promoted the proliferation and migration of tumor cells, which was associated with elevated activation of Rat sarcoma/Mitogen-activated protein kinases (Ras/MAPK) signaling and increased expression of cyclin D1, cyclin D-dependent kinases 4 (CDK4), matrix metalloproteinase 2 (MMP2) and Ras homolog gene family member A (RhoA). In contrast, knockdown of KLHL17 in the cell lines of NSCLC using KLHL17 small interfering RNA suppressed the proliferation and migration of tumor cells, in association with reduced activation of Ras/MAPK signaling and decreased expression of cyclin D1, CDK4, MMP2 and RhoA. Moreover, treatment of tumor cells with Ras inhibitor salirasib prevented KLHL17-induced Ras/MAPK activity as well as tumor proliferation and migration. These results suggest that upregulated KLHL17 in NSCLC promotes the proliferation and migration of tumor by activating Ras/MAPK signaling pathway. Therefore, KLHL17 may be a novel therapeutic target for the treatment of NSCLC.

Ring finger protein 19A is overexpressed in non-small cell lung cancer and mediates p53 ubiquitin-degradation to promote cancer growth.

The expression pattern, biological functions and the related mechanisms of the ring finger protein 19A (RNF19A) in non-small cell lung cancer (NSCLC) remain poorly understood. This study aimed to explore the role of RNF19A, as well as the underlying potential mechanism, in the development of NSCLC. Here, we found that RNF19A was overexpressed in NSCLC tissues, and RNF19A expression in NSCLC tissue samples was associated with NSCLC carcinogenesis and poor outcome. RNF19A promoted the proliferation of NSCLC cells and inhibited apoptosis. RNF19A reduced p53, p21 and BAX expression and induced Cyclin D1, CDK4, CDK6 and BCL2 expression. The inhibitory effect of RNF19A knockdown on proliferation was partially rescued by p53 silencing. RNF19A interacted with p53, shortened p53 half-life and mediated p53 ubiquitin-degradation. Collectively, we suggest that RNF19A plays a critical oncogenic role in lung carcinogenesis by disrupting the function of p53. RNF19A may serve as a new biomarker and/or target for NSCLC management.

MZT2A promotes NSCLC viability and invasion by increasing Akt phosphorylation via the MOZART2 domain.

Mitotic spindle organizing protein 2A (MZT2A) is localized at the centrosome and regulates microtubule nucleation activity in cells. This study assessed the role of MZT2A in non-small-cell lung cancer (NSCLC). Differential MZT2A expression was bioinformatically assessed using TCGA database, the GEPIA database, and Kaplan-Meier survival data to determine the association between MZT2A expression and NSCLC prognosis. Furthermore, NSCLC tissue specimens were evaluated by immunohistochemistry. MZT2A was overexpressed or knocked down in NSCLC cells using cDNA and siRNA, respectively. The cells were subjected to various assays and treated with the selective Akt inhibitor LY294002 or co-transfected with galectin-3-binding protein (LGALS3BP) siRNA. MZT2A mRNA and protein levels were upregulated in NSCLC lesions and MTZ2A expression was associated with poor NSCLC prognosis. MZT2A protein was also highly expressed in NSCLC cells compared with the expression in normal bronchial cells. MZT2A expression promoted NSCLC cell viability and invasion, whereas MTZ2A siRNA had the opposite effect on NSCLC cells in vitro. At the protein level, MZT2A induced Akt phosphorylation, promoting NSCLC proliferation and invasion (but the selective Akt inhibitor blocked these effects) through upregulation of LGALS3BP via the MTZ2A MOZART2 domain, whereas LGALS3BP siRNA suppressed MTZ2A activity in NSCLC cells. The limited in vivo experiments confirmed the in vitro data. In conclusion, MZT2A exhibits oncogenic activity by activating LGALS3BP and Akt in NSCLC. Future studies will assess MTZ2A as a biomarker to predict NSCLC prognosis or as a target in the control of NSCLC progression.

PCGF3 promotes the proliferation and migration of non-small cell lung cancer cells via the PI3K/AKT signaling pathway.

The Polycomb Group Ring Finger 3 (PCGF3) protein has been reported to be significantly upregulated in pancreatic islet tumors and related to signal transduction; however, its detailed mechanisms and biological roles in other tumors, including non-small cell lung cancer (NSCLC), remain unclear. This study investigated the function of PCGF3 in NSCLC and further elucidated its mechanism of action. The immunohistochemical analysis of 86 selected lung cancer tissues revealed that PCGF3 was highly expressed in NSCLC tissues and positively correlated with lymph node metastasis and p-TNM staging. Additionally, PCGF3 promoted cell proliferation in lung cancer by regulating CyclinB1, CyclinD1, and CDK4 expression, and also promoting their migration by regulating RhoA, RhoC, and CDC42. Furthermore, PCGF3 affected both the proliferation and migration of lung cancer cells by regulating the PI3K/AKT pathway, as verified by inhibiting this pathway using LY294002. The findings of this study suggested that PCGF3 is associated with poor prognosis in patients with NSCLC and could therefore be an important biomarker for treating and preventing NSCLC.

Annexin A7 and JNK knockdown suppress the lymphatic metastasis potential of hepatocellular carcinoma cells: Possible contributions of ATF2 and sequence-related lncRNA NONMMUT114121.1.

BACKGROUND: Our previous studies identified the calcium-dependent phospholipid binding protein Annexin A7 (ANXA7) as a critical mediator of hepatocellular carcinoma (HCC) lymph node metastasis (LNM) in mice, possibly through c-Jun N-terminal kinase (JNK) signaling. Activating transcription factor-2 (ATF2) is a downstream target of JNK, so we examined if modulation of LNM capacity by ANXA7 and JNK is associated with changes in ATF2 activity and its sequence-related long non-coding (lnc)RNA NONMMUT114121.1. METHODS: The effects of shRNA-induced ANXA7 and JNK knockdown on HCC cell transwell invasion, HCC cell lymphatic tissue adherence, ATF2 mRNA and protein expression, and ATF2 subcellular distribution were examined in the murine HCC cell line Hca-P. RESULTS: Invasive capacity, lymphoid adhesion, and ATF2 expression at both mRNA and protein levels were significantly reduced by ANXA7 or JNK knockdown (all P<0.05). Immunofluorescence revealed that ATF2 was mainly localized to the nucleus of control Hca-P cells, but this nuclear expression was markedly reduced by ANXA7 or JNK knockdown. LncRNA NONMMUT114121.1 was associated with ATF2 by sequencing and its expression level was significantly increased by ANXA7 knockdown (P<0.05). CONCLUSIONS: JNK and ANXA7 promote the invasive capacity and lymphatic adherence of Hca-P cells, possibly through ATF2 activation and its related lncRNA NONMMUT114121.1. Nuclear ATF2 may thus be a potential diagnostic and/or prognostic biomarker for HCC.

KLHL18 inhibits the proliferation, migration, and invasion of non-small cell lung cancer by inhibiting PI3K/PD-L1 axis activity.

BACKGROUND: The expression of Kelch-like protein 18 (KLHL18) in non-small cell lung cancer (NSCLC) is lower than that in normal lung tissue according to the Gene Expression Profiling Interactive Analysis database. KLHL18 is a BTB domain protein and binds cullin 3 (CUL3). However, whether this complex participates in ubiquitination-mediated protein degradation in NSCLC is unclear. Therefore, we aimed to investigate the role of KLHL18 in human NSCLC cells. RESULTS: We found that KLHL18 is downregulated in cancer cells and is associated with poor prognosis. Further, its expression was significantly associated with tumor node metastasis (TNM) stage, lymph node metastasis, and tumor size. In vitro analysis of NSCLC cells showed that overexpressing KLHL18 inhibited cell proliferation, migration, and invasion. We found that the tumor-inhibitory effect of the KLHL18 protein was achieved by promoting the ubiquitination and degradation of phosphatidylinositol 3-kinase (PI3K) p85α and inhibiting the expression of PD-L1 protein, ultimately preventing tumor cell immune escape. CONCLUSIONS: Our results identified the tumor-suppressive mechanism of KLHL18 and suggested that it is closely related to NSCLC occurrence and development. Further investigation of the underlying mechanism may provide new targets for NSCLC treatment.

Enhanced tumorigenesis and lymphatic metastasis of CD133+ hepatocarcinoma ascites syngeneic cell lines mediated by JNK signaling pathway in vitro and in vivo.

Cancer stem cells (CSCs), stem-like cells, or tumor-initiating cells (TICs) may initiate tumorigenesis and metastasis, but neither the basic cell biology of CSCs nor the mechanisms of CSC-mediated tumor growth and lymphoid node metastasis are understood. Evidence suggests that CSC phenotype is maintained, at least in part, by altered JNK signaling. In this study, factors influencing the growth and metastatic potential of CSCs were examined by comparing CD133 surface antigen expression, proliferation, clonogenicity, invasive capacity, tumorigenicity, and expression of JNK-associated signaling molecules between the highly metastatic mouse hepatocarcinoma ascites syngeneic cell line Hca-F and the low metastasis potential line Hca-P. The Hca-F line exhibited higher clonogenic, proliferative, and invasive capacities than Hca-P cells, and a greater proportion of Hca-F cells were CD133 positive. In both cell lines, the CD133+ subpopulation showed significantly enhanced tumorigenicity and metastatic potential. An in vivo tumorigenicity assay in nude mice indicated that Hca-F cells possessed significantly higher tumorigenicity than Hca-P cells as indicated by larger tumors after inoculation. Expression levels of E-cadherin (CDH1), annexin VII, and JNK1 proteins were inversely correlated with CD133 expression in both Hca-F and Hca-P cells. These results demonstrate that CD133+ subpopulations of both Hca-F and Hca-P lines show CSC-like properties. However, Hca-F cells showed greater tumorigenicity and invasiveness, consistent with greater lymphatic metastasis capacity. We propose that tumorigenesis and lymphatic metastasis are regulated by JNK/P53/annexin VII and JNK/ATF-2/CDH1/annexin VII signal transduction pathways.

Annexin A7 gene is an important factor in the lymphatic metastasis of tumors.

In the tumor malignancy progression, lymph node metastasis (LNM) is recognized as an important factor. In this study, RNA interference (RNAi) was employed to down-regulate ANXA7 gene in Hca-F cells, a hepatocarcinoma cell line with high LNM rate. There was no significant effect on cell proliferation ability, but cell division, motility, and invasion abilities were markedly inhibited. By contrast, up-regulating the expression of ANXA7 gene in Hca-P cells with lower LNM rate, cell migration ability was improved and the percentage of cells in S phase was significantly decreased in vitro. Here, we reported that the expression of Ech1, GSN and JNK1 genes, which were relevant to tumor lymphatic metastasis, had been inhibited due to down-regulation ANXA7 gene and promoted due to up-regulation ANXA7 gene by western blot analysis. These results indicated that ANXA7 is a critical factor in the development of lymphatic metastasis in hepatocarcinoma progression.