Background Cisplatin (DDP) is the first-line chemotherapeutic drug for non-small cell lung cancer (NSCLC), and long-term DDP stimulation increased resistance of NSCLC cells to this drug by enriching cancer stem cells (CSCs), which contributed to recurrence and worse prognosis of NSCLC, but the molecular mechanisms are still not fully delineated. Methods Real-Time qPCR and Western Blot analysis were conducted to examine gene expressions at mRNA and protein levels, respectively. Dual-luciferase reporter gene system was used to validate the targeting sites among circRNA CDR1as, miR-641 and HOXA9 mRNA. Cell growth was evaluated by CCK-8 assay, trypan blue staining assay and colony formation assay. The Annexin V-FITC/PI double staining method was employed to measure cell apoptosis ratio. Spheroid formation and flow cytometer assay was used to evaluate cell stemness. Xenograft mice models were established to measure tumorgenicity in vivo, and Ki67 expressions in mice tumor tissues were examined by immunohistochemistry (IHC). Results Here we identified a novel circRNA CDR1as/miR-641/Homeobox protein Hox-A9 (HOXA9) pathway regulated stemness and DDP chemoresistance in NSCLC. Mechanistically, circRNA CDR1as and HOXA9 were high-expressed, while miR-641 was low-expressed in DDP-resistant NSCLC cells, instead of their corresponding parental DDP-sensitive NSCLC cells. Additionally, we validated that circRNA CDR1as positively regulated HOXA9 in NSCLC cells by serving as an RNA sponge for miR-641, and knock-down of circRNA CDR1as increased the sensitivity of DDP-resistant NSCLC cells, which were reversed by downregulating miR-641 and upregulating HOXA9. Consistently, overexpression of circRNA CDR1as increased drug resistance of DDP-sensitive NSCLC cells by regulating miR-641/HOXA9 axis. In addition, the expression levels of stemness signatures (SOX2, OCT4 and Nanog) were higher in DDP-resistant NSCLC cells, which also tended to form spheres and enrich CD44+CD166+ population compared to their parental DDP-sensitive NSCLC cells, suggesting that CSCs were enriched in DDP-resistant NSCLC cells. Notably, knock-down of circRNA CDR1as inhibited stemness of DDP-resistant NSCLC cells by inhibiting HOXA9 through upregulating miR-641. Conclusions Taken together, this study identified that circRNA CDR1as regulated stemness and DDP chemoresistance in NSCLC cells by targeting miR-641/HOXA9 axis.

The clinical relevance of regulatory T cell (Treg) infiltration in breast cancer (BC) remains controversial, and no recent meta-analysis has been published on this subject. Our aim was to identify the precise relationship between Tregs and the prognosis and clinic-pathological features of BC. Eligible articles were identified with a MEDLINE database search over a period up to March 2015. Our meta-analysis was performed using STATA software 11.0 and Review Manager 5.3. The correlations between Treg infiltration and clinico-pathological features and BC prognosis were analyzed. Subgroup and sensitivity analyses, as well as meta-regression, were conducted. Eighteen published studies (including 8,562 patients) were eligible. Overall survival (OS) and disease-, recurrence-, and progression-free survival (DFS/RFS/PFS) were correlated with Treg infiltration (OR=2.03 (95% CI, 1.40-2.95; P=0.000) and 1.48 (95% CI, 1.00-2.19; P=0.050), respectively), including 3-, 5-, and 10-year mortality rates. In addition, low Treg infiltration was present in estrogen receptor (ER)-positive tumors (P=0.000), progesterone receptor (PR)-positive tumors (P=0.003), Her2-negative tumors (P=0.000) and histological grade I/II tumors (P=0.001). No publication bias was observed with the exception of OS. Subgroup analysis suggested that the mortality rate of the high Treg infiltration subgroup was increased compared with the low Treg infiltration subgroup among ER-positive patients. Treg infiltration indicated a poorer prognosis for BC and is related to ER, PR, and Her2 status and histological grade. Thus, Treg infiltration could help predict outcomes and guide clinical therapy.

To investigate the role of miR-625 on the invasion, migration, and epithelialmesenchymal transition (EMT) of non-small cell lung carcinoma (NSCLC) cells, and the related mechanisms. Materials and Methods: The expression levels of miR-625 and Resistin mRNA in 80 pairs of NSCLC and para-cancerous lung tissues were analyzed by RT-PCR. The relationship between miR-625 and Resistin was predicted by bioinformatics and verified by a dualluciferase gene reporter assay. NSCLC cells were transfected with Resistin plasmids, si-Resistin plasmids, miR-625 mimics, or miR-625 inhibitors, and proliferation, invasion, and migration were determined by CCK-8, Transwell, and wound scratch assays, respectively. EMT-related proteins were determined by Western blot assay. A xenograft model of NSCLC was established in nude mice to validate the in vitro findings. Results: MiR-625 was significantly downregulated in NSCLC tissue compared to paired para-cancerous lung tissues, while Resistin was markedly increased in tumor tissue. The expression levels of miR-625 and Resistin were negatively correlated in NSCLC tissues, and high levels of Resistin correlated with greater tumor differentiation, more advanced clinical staging, and lymph node metastasis. Furthermore, Resistin was a target gene of miR-625, and the latter downregulated Resistin to inhibit the EMT, proliferation, invasion, and migration of NSCLC cells in vitro, likely via the PI3K/AKT/Snail signaling pathway. Finally, miR-625 also inhibited the tumorigenic effect of NSCLC cells in vivo by downregulating Resistin. Conclusion: MiR-625 acts as a tumor suppressor in NSCLC and inhibits tumor cell invasion and metastasis by blocking the Resistin/PI3K/AKT/Snail pathway and by decreasing EMT.

BackgroundPhosphatase and tensin homolog (PTEN), regarded as a tumor suppressor gene, may act as a prognostic biomarker in human cancers.MethodsAll eligible studies from MEDLINE, Embase, CENTRAL, and the Chinese BioMedical Literature Database to October 2016 were incorporated. Two reviewers independently screened the literature according to inclusion and exclusion criteria, extracted the data, assessed the methodological quality of the included studies, and conducted meta‐analysis.ResultsA total of 2486 patients from 19 studies were included. PTEN expression was significantly correlated with gender, smoking history, histology (adenocarcinoma [ADC] vs. squamous cell carcinoma), tumor node metastasis stage (I–II vs. III–IV), N status (N0 vs. N1–N3), and distant metastasis (M0 vs. M1). Loss of PTEN expression was associated with poorer overall survival, but had no significant association with disease‐free survival. Subgroup analysis showed that negative PTEN expression was associated with a poorer outcome in Asian and ADC patients, but not in Western or squamous cell carcinoma patients.ConclusionLoss of PTEN might play an unfavorable prognostic role for overall survival of non‐small cell lung cancer patients, especially Asian or ADC patients.