TIMM50 promotes tumor progression via ERK signaling and predicts poor prognosis of non-small cell lung cancer patients.

TIMM50 (Translocase of the inner mitochondrial membrane 50), also called TIM50, plays an essential role in mitochondrial membrane transportation. The existing literature suggests that TIMM50 may perform as an oncogenetic protein in breast cancer. However, the molecular mechanism, especially in human non-small cell lung cancer (NSCLC), is uncertain to date. In the present study, using immunohistochemistry, we found that TIMM50 expression significantly correlated with larger tumor size (P = 0.049), advanced TNM stage (P = 0.001), positive regional lymph node metastasis (P = 0.007), and poor overall survival (P = 0.001). Proliferation and invasion assay showed that TIMM50 dramatically promoted the ability of proliferation and invasion of NSCLC cells. Subsequent Western blotting results revealed that TIMM50 enhanced the expression of Cyclin D1 and Snail, and inhibited the expression of E-cadherin. Moreover, TIMM50 facilitated the expression of phosphorylated ERK and P90RSK. Incorporation of ERK inhibitor counteracted the upregulating expression of CyclinD1, and Snail, and downregulating expression of E-cadherin expression induced by TIMM50 overexpression. In conclusion, our data indicated that TIMM50 facilitated tumor proliferation and invasion of NSCLC through enhancing phosphorylation of its downstream ERK/P90RSK signaling pathway. We speculated that TIMM50 might be a useful prognosis marker of NSCLC patients.

P130cas-FAK interaction is essential for YAP-mediated radioresistance of non-small cell lung cancer.

Based on the RNA-sequencing data, previous studies revealed that extracellular matrix receptor interaction and focal adhesion signaling pathways were enriched in radioresistant non-small cell lung cancer (NSCLC) cell lines. As the principal members of these signaling pathways, recent studies showed that FAK controlled YAP's nuclear translocation and activation in response to mechanical activation. However, the underlying mechanisms are largely unknown. This study was designed to determine whether P130cas plays a role in FAK-YAP axis-mediated radioresistance. We found that P130cas promoted proliferation, altered the cell cycle profile, and enhanced tumor growth using cell lines and xenograft mouse models. After treating the cell lines and xenograft models with a single dose of 5 Gy irradiation, we observed that P130cas effectively induced radioresistance in vitro and in vivo. We confirmed that P130cas interacted with and promoted YAP stabilization, thereby facilitating YAP's activation and nuclear translocation and downregulating the radiosensitivity of NSCLC. Our data also revealed that P130cas and FAK directly interacted with each other and worked together to regulate YAP's activation and nuclear translocation. Furthermore, the present study identified that P130cas, FAK and YAP formed a triple complex to induce radioresistance. Using P130cas-ΔSH3, FAK- P712/715A mutant, YAP-ΔSH3bm and YAP-ΔWW mutant, our results showed that targeting P130cas-FAK interaction may be a more cost-effective way to overcome the YAP activation mediated radioresistance in NSCLC. Using the data of the public database and our clinical samples, the present study suggested that the expression of P130cas correlated with YAP expression and indicated a poor overall response rate of NSCLC patients who underwent radiation therapy. Overall, our study extends the knowledge of FAK-YAP interaction and provides new insight into understanding the underlying mechanisms to overcome the radioresistance of NSCLC.

FAM110B Inhibits Non-Small Cell Lung Cancer Cell Proliferation and Invasion Through Inactivating Wnt/ß-Catenin Signaling.

PURPOSE: FAM110B is a member of the FAM110 family (family with sequence similarity 110), which is a component of the centrosome associated proteins. Previous studies have shown that FAM110B may be involved in the process of cell cycle and may play a role in carcinogenesis and tumor progression. Using an online database, we found that FAM110B may predict favorable prognosis in non-small cell lung cancer (NSCLC). Therefore, the role of FAM110B playing in NSCLC needs to be further investigated. PATIENTS AND METHODS: Online databases and immunohistochemistry were used to predict the expression and prognostic value of FAM110B in NSCLC samples. Immunofluorescence staining was used to investigate the subcellular distribution of FAM110B. Western blot, MTT, colony formation, and matrigel invasion assay were used to detect the expression and the effect of FAM110B on mediating proliferation and invasion in NSCLC cell lines. RESULTS: In this study, immunohistochemistry results showed that FAM110B expression significantly correlated with early TNM staging (P=0.020) and negative regional lymph node metastasis (P=0.006). Kaplan-Meier survival analysis found that the median survival time of patients with positive FAM110B expression (56.181±2.348 months) was significantly longer than those with negative FAM110B expression (47.701±2.997 months, P=0.024). Moreover, overexpression of FAM110B inhibited the proliferation and invasion of A549, H1299, and LK2 cell lines. Conversely, FAM110B RNAi exerted opposite effects in the above cell lines. Furthermore, FAM110B overexpression downregulated the active ß-catenin, phosphorylation of GSK-3ß (p-GSK-3ß), cyclin B1, cyclin D1, MMP2, and MMP7, and upregulated the phosphorylation of ß-catenin (p-ß-catenin) in A549 and H1299 cells. Besides, the FAM110B-induced depressions of p-GSK-3ß and active ß-catenin were reversed after being treated with Wnt/ß-catenin inhibitor, XAV-939. CONCLUSION: In summary, our results demonstrated that the overexpression of FAM110B restricts the proliferation and invasion of NSCLC cells by inhibiting Wnt/ß-catenin signaling. Our study reveals the antitumor function of FAM110B in NSCLC and indicates that FAM110B is a potential therapeutic target.

FAM163A, a positive regulator of ERK signaling pathway, interacts with 14-3-3ß and promotes cell proliferation in squamous cell lung carcinoma.

PURPOSE: FAM163A, also called neuroblastoma-derived secretory protein (NDSP) or C1ORF76, was newly found on chromosome 1q25.2. Previous studies of FAM163A focused on its expression and function in neuroblastoma. However, using an online database, we found that FAM163A may predict poor prognosis in lung squamous cell carcinomas (LUSC). Therefore, the role of FAM163A plays in LUSC needs to be further clarified. PATIENTS AND METHODS: Western blots, immunofluorescence and immunohistochemistry were used to detect the effect of FAM163A on mediating cell proliferation in vitro and in vivo. Co-immunoprecipitation and immunofluorescence were utilized to evaluate the interaction and co-localization of FAM163A with 14-3-3ß and ERK. RESULTS: In this study, our data revealed that FAM163A overexpression increased the levels of ERK and p90RSK phosphorylation and promoted the expression of cyclin D1. Incorporation with U0126 reversed the effects of FAM163A overexpression. FAM163A directly interacted with both 14-3-3ß and ERK and regulated the phosphorylation of ERK by upregulating the protein level of 14-3-3ß. Immunohistochemistry results also showed that FAM163A expression significantly correlated with larger tumor size (P=0.023), TNM staging (P=0.015) and regional lymph node metastasis (P=0.016). Kaplan-Meier survival analysis implied the mean survival time of patients with positive FAM163A expression (49.72±3.97 months) was much shorter than the patients with negative FAM163A expression (63.36±3.14 months, P=0.011). CONCLUSION: In summary, the present study identified a novel mechanism that FAM163A, through binding and upregulating 14-3-3ß, facilitated ERK phosphorylation that led to an increase of cellular proliferation of LUSC cells. FAM163A may be a useful marker to predict poor prognosis of patients with LUSC.

Fbxo6 confers drug-sensitization to cisplatin via inhibiting the activation of Chk1 in non-small cell lung cancer.

Fbxo6 (also called FBG2) is a critical component of the evolutionarily conserved ubiquitin-protein ligase complex SCF (Skp1/Cdc53-Cullin1/F-box). Previous studies have demonstrated that Fbxo6 facilitates the growth and proliferation but inhibits the apoptosis and invasion of gastric cancer cells. However, the role of Fbxo6 in non-small cell lung cancer (NSCLC) is still not clear. Our results revealed that Fbxo6 expression is correlated with early TNM stage and favorable overall survival of NSCLC patients. Further in vitro experiments showed that Fbxo6 inhibits proliferation, facilitates apoptosis and promotes the sensitivity of cisplatin via decreased expression and phosphorylation of Chk1. Thus, Fbxo6 may be a useful prognosis marker and therapeutic target to overcome the chemoresistance of cisplatin-based chemotherapy agents in NSCLC patients.