mPRα mediates P4/Org OD02-0 to improve the sensitivity of lung adenocarcinoma to EGFR-TKIs via the EGFR-SRC-ERK1/2 pathway.

The discovery of epidermal growth factor receptor (EGFR) mutations has made EGFR tyrosine kinase inhibitors (EGFR-TKIs) a milestone in the treatment for advanced non-small cell lung cancer (NSCLC). However, patients lacking EGFR mutations are not sensitive to EGFR-TKI treatment and the emergence of secondary resistance poses new challenges for the targeted therapy of lung cancer. In this study, we identified that the expression of membrane progesterone receptor α (mPRα) was associated with EGFR mutations in lung adenocarcinoma patients and subsequently affected the efficacy of EGFR-TKIs. Progesterone (P4) or its derivative Org OD02-0 (Org), which is mediated by mPRα, increases the function of EGFR-TKIs to suppress the proliferation, migration, and invasion of lung adenocarcinoma cells in vitro and in vivo. In addition, the mPRα pathway triggers delayed resistance to EGFR-TKIs. Mechanistic investigations demonstrated that the mPRα pathway can crosstalk with the EGFR pathway by activating nongenomic effects to inhibit the EGFR-SRC-ERK1/2 pathway, thereby promoting antitumorigenic effects. In conclusion, our data describe an essential role for mPRα in improving sensitivity to EGFR-TKIs, thus rationalizing its potential as a therapeutic target for lung adenocarcinomas.

MiR-924 as a tumor suppressor inhibits non-small cell lung cancer by inhibiting RHBDD1/Wnt/ß-catenin signaling pathway.

BACKGROUND: MiR-924 has been reported to be a tumor suppressor in hepatocellular carcinoma. However, the functions and mechanisms of miR-924 in non-small cell lung cancer (NSCLC) remain unclear. METHODS: The expression of miR-924 was determined in NSCLC tissues and cell lines using quantitative real time PCR. The Chi-squared test was used to evaluate the correlation between miR-924 levels and clinicopathological parameters in patients with NSCLC. Cell proliferation was assessed by CCK-8 assay. Cell migration and invasion were detected by transwell assay. The combination of miR-924 and RHBDD1 was analyzed via the luciferase reporter assay. The expression level of RHBDD1 was evaluated in lung cancer tissues using public microarray datasets form Oncomine and its prognostic value was assessed by Kaplan-Meier Plotter databases. A tumor xenograft mouse model was established to illustrate the effects of miR-924 on the tumorigenesis of NSCLC in vivo. RESULTS: In this study, we found miR-924 was strikingly decreased in NSCLC tissues and cell lines. Decreased miR-924 was closely correlated with advanced tumor-node-metastasis (TNM) stage and lymphatic metastasis in NSCLC patients. Noticeably, rhomboid domain-containing protein 1 (RHBDD1) was predicted and confirmed as a direct target of miR-924. Moreover, the expression level of RHBDD1 was significantly increased and inversely associated with prognosis using public microarray datasets form Oncomine and Kaplan-Meier Plotter databases. MiR-924 overexpression suppressed cell proliferation, migration and invasion. The in vivo experiments further demonstrated that miR-924 overexpression reduced NSCLC xenograft growth through inhibiting RHBDD1/Wnt/ß-catenin signaling pathway. CONCLUSIONS: In summary, these findings demonstrated that miR-924 blocked the progression of NSCLC by targeting RHBDD1 and miR-924/RHBDD1 axis might provide a novel therapeutic target for the treatment of NSCLC.

KANK3 mediates the p38 MAPK pathway to regulate the proliferation and invasion of lung adenocarcinoma cells.

BACKGROUND: Lung adenocarcinoma (LUAD) is one of the major subtypes of lung cancer and is the most common cause of cancer deaths globally. The Kank (kidney or KN motif and ankyrin repeat domain-containing) family of proteins has been characterized as critical for regulating the capacity of cells to migrate and their anti-tumor drug sensitivity. The current research designs to explore the specific effects and potential regulatory molecular mechanism of KANK3 on LUAD cells. METHOD: Two datasets (TCGA-LUAD and GSE116959) were analyzed to confirm the differently expressed genes. qRT-PCR was carried out to measure KANK3 level in LUAD tissue samples and adjacent non-cancerous tissue samples. Western blot assay was utilized to investigate the KANK3, p-p38 and p38 protein levels. MTT assay were employed to investigate the cell proliferation. Cell invasion and migration were assessed using Transwell and wound healing assay. RESULT: KANK3 was down-regulated in LUAD tissues and the expressions of KANK3 had a strong influence on prognosis of LUAD patients. Overexpression of KANK3 significantly inhibited， whereas KANK3 silencing observably enhanced the capacity of NCI-H1975 and PC-9 cells to proliferate, invade and migrate. GSEA showed that, differentially expressed genes which regulated by KANK3 enriched in cell adhesion, chemokine, focal adhesion or MAPK signaling pathway. Further experiments proved that KANK3 regulated LUAD cells proliferation and metastasis through p38 MAPK pathway. CONCLUSION: KANK3 exerts antitumor effect in LUAD through regulation of p38 MAPK signaling pathway. These outcomes foreboded that KANK3 could be a novel therapeutic target for further study of LUAD.

Comprehensive analyses reveal the prognosis and biological function roles of chromatin regulators in lung adenocarcinoma.

The present study explored the prognosis and biological function roles of chromatin regulators (CRs) in patients with lung adenocarcinoma (LUAD). Using transcriptome profile and clinical follow-up data of LUAD dataset, we explored the molecular classification, developed, and validated a CR prognostic model, built an individual risk scoring system in LUAD, and compared the clinical and molecular characteristics between different subtypes and risk stratifications. We investigated the chemotherapy sensitivity and predicted potential immunotherapy response. Lastly, we collected the clinical samples and validated the prognosis and potential function role of NAPS2. Our study indicated that LUAD patients could be classified into two subtypes that had obviously different clinical background and molecular features. We constructed a prognostic model with eight CR genes, which was well validated in several other population cohort. We built high- and low-risk stratifications for LUAD patients. Patients from high-risk group were totally different from low-risk groups in clinical, biological function, gene mutation, microenvironment, and immune infiltration levels. We idented several potential molecular compounds for high-risk group treatment. We predicted that high-risk group may have poor immunotherapy response. We finally found that Neuronal PAS Domain Protein 2 (NPAS2) involved in the progression of LUAD via regulating cell adhesion. Our study indicated that CR involved in the progression of LUAD and affect their prognosis. Different therapeutic strategies should be developed for different molecular subtypes and risk stratifications. Our comprehensive analyses uncover specific determinants of CRs in LUAD and provides implications for investigating disease-associated CRs.

Development and Validation of a Prognostic Nomogram for Lung Adenocarcinoma: A Population-Based Study.

Purpose: To establish an effective and accurate prognostic nomogram for lung adenocarcinoma (LUAD). Patients and Methods. 62,355 LUAD patients from 1975 to 2016 enrolled in the Surveillance, Epidemiology, and End Results (SEER) database were randomly and equally divided into the training cohort (n = 31,179) and the validation cohort (n = 31,176). Univariate and multivariate Cox regression analyses screened the predictive effects of each variable on survival. The concordance index (C-index), calibration curves, receiver operating characteristic (ROC) curve, and area under the ROC curve (AUC) were used to examine and validate the predictive accuracy of the nomogram. Kaplan-Meier curves were used to estimate overall survival (OS). Results: 10 prognostic factors associated with OS were identified, including age, sex, race, marital status, American Joint Committee on Cancer (AJCC) TNM stage, tumor size, grade, and primary site. A nomogram was established based on these results. C-indexes of the nomogram model reached 0.777 (95% confidence interval (CI), 0.773 to 0.781) and 0.779 (95% CI, 0.775 to 0.783) in the training and validation cohorts, respectively. The calibration curves were well-fitted for both cohorts. The AUC for the 3- and 5-year OS presented great prognostic accuracy in the training cohort (AUC = 0.832 and 0.827, respectively) and validation cohort (AUC = 0.835 and 0.828, respectively). The Kaplan-Meier curves presented significant differences in OS among the groups. Conclusion: The nomogram allows accurate and comprehensive prognostic prediction for patients with LUAD.

Cross-Talk between Oxidative Stress and m6A RNA Methylation in Cancer.

Oxidative stress is a state of imbalance between oxidation and antioxidation. Excessive ROS levels are an important factor in tumor development. Damage stimulation and excessive activation of oncogenes cause elevated ROS production in cancer, accompanied by an increase in the antioxidant capacity to retain redox homeostasis in tumor cells at an increased level. Although moderate concentrations of ROS produced in cancer cells contribute to maintaining cell survival and cancer progression, massive ROS accumulation can exert toxicity, leading to cancer cell death. RNA modification is a posttranscriptional control mechanism that regulates gene expression and RNA metabolism, and m6A RNA methylation is the most common type of RNA modification in eukaryotes. m6A modifications can modulate cellular ROS levels through different mechanisms. It is worth noting that ROS signaling also plays a regulatory role in m6A modifications. In this review, we concluded the effects of m6A modification and oxidative stress on tumor biological functions. In particular, we discuss the interplay between oxidative stress and m6A modifications.

Silencing ZIC2 abrogates tumorigenesis and anoikis resistance of non-small cell lung cancer cells by inhibiting Src/FAK signaling.

Aberrant expression of the zinc finger protein (ZIC) family has been extensively reported to contribute to progression and metastasis in multiple human cancers. However, the functional roles and underlying mechanisms of ZIC2 in non-small cell lung cancer (NSCLC) are largely unknown. In this study, ZIC2 expression was evaluated using qRT-PCR, western blot, and immunohistochemistry, respectively. Animal experiments in vivo and functional assays in vitro were performed to investigate the role of ZIC2 in NSCLC. Luciferase assays and chromatin immunoprecipitation (ChIP) were carried out to explore the underlying target involved in the roles of ZIC2 in NSCLC. Here, we reported that ZIC2 was upregulated in NSCLC tissues, and high expression of ZIC2 predicted worse overall and progression-free survival of NSCLC patients. Silencing ZIC2 repressed tumorigenesis and reduced the anoikis resistance of NSCLC cells. Mechanical investigation further revealed that silencing ZIC2 transcriptionally inhibited Src expression and inactivated steroid receptor coactivator/focal adhesion kinase signaling, which further attenuated the anoikis resistance of NSCLC cells. Importantly, our results showed that the number of circulating tumor cells (CTCs) was positively correlated with ZIC2 expression in NSCLC patients. Collectively, our findings unravel a novel mechanism implicating ZIC2 in NSCLC, which will facilitate the development of anti-tumor strategies in NSCLC.