β-Elemene Restrains PTEN mRNA Degradation to Restrain the Growth of Lung Cancer Cells via METTL3-Mediated N6 Methyladenosine Modification

Lung cancer is one of the most fatal malignancies and the leading cause of cancer death worldwide. β-Elemene, a well-known anticancer drug, has drawn a great deal of attention from researchers attributed to its limited side impacts. N6-Methyladenosine (m6A) modification is the most common RNA modification and plays a vital role in the pathogenesis of multiple tumors. However, the functional link between β-elemene and the m6A modification in lung cancer development remains unexplored. In this study, we investigated whether m6A modification was responsible for the impacts of β-elemene on lung cancer. Firstly, outcomes suggested that β-elemene restrained the malignant behaviors of A549 together with H1299 cells. Thereafter, we observed that β-elemene markedly regulated METTL3, YTHDF1, and YTHDC1 among various m6A modulators. METTL3 was selected for further study because of its oncogenic function in lung cancer. RT-qRCR and western blot assays exhibited that the mRNA and protein expression levels of METTL3 were lessened by the administration of β-elemene. Mechanistically, β-elemene exerted the restrictive impacts on the cell growth of lung cancer in vivo and in vitro through targeting METTL3. More importantly, β-elemene contributed to the augmented PTEN expression via suppressing its m6A modification. To sum up, we provided strong clues that β-elemene promoted PTEN expression to retard lung cancer progression by the regulation of METTL3-mediated m6A modification.

PTEN promoter methylation predicts 10-year prognosis in hormone receptor-positive early breast cancer patients who received adjuvant tamoxifen endocrine therapy

Purpose There remain a lack of biomarkers for endocrine therapy resistance in patients with breast cancer (BC), which is proving to be a great challenge. In vitro experiments have shown that downregulation of PTEN expression leads to resistance to tamoxifen (TAM) in BC cells. We aimed to investigate the predictive role of tumor PTEN promoter methylation and PTEN expression in long-term survival after TAM adjuvant therapy in patients with early-stage BC. Methods From 2001 to 2013, 105 patients with stage I–III BC who were treated with standardized adjuvant TAM for 5 years or until relapse in West China Hospital (WCH) were enrolled in this study. PTEN expression and DNA methylation of three specified sequences from the PTEN promoter in primary tumors were measured using immunohistochemistry and pyrosequencing. A cohort of 159 hormone receptor-positive patients receiving TAM treatment from The Cancer Genome Atlas (TCGA) database was used for verification. Results Median follow-up time for the WCH cohort was 141.7 months. The low, moderate, and high PTEN expression groups had differing 10-year disease-free survival (DFS) (42.3%, 55%, 81%, respectively, P = 0.027) and overall survival (OS) rates (65%, 84.2%, 90.5%, respectively, P = 0.027). Higher methylation levels of the second sequence (− 819 to − 787 bp), rather than the first (− 1143 to − 1107 bp) or third sequence (− 663 to − 593 bp), independently increased the risk of disease recurrence (hazard ratio = 2.60) and death (hazard ratio = 3.79) in the WCH cohort, according to multivariate Cox regression analysis. Importantly, out of the five CpG islands located within this sequence, only high methylation of the − 796 CpG island predicted shorter DFS and OS. In TCGA validation cohort, there was also a trend of higher methylation of the − 796 CpG island correlating with shorter disease-free intervals, with borderline significance (P = 0.057). Conclusion Low PTEN expression and high methylation of its promoter (sequence − 819 to − 787 bp) in tissue predict poor DFS and OS in hormone receptor-positive early BC patients who received adjuvant TAM.

Prevalence and Factors Associated with the Loss of PTEN Expression in Patients with Lung Cancer

Background: Phosphatase and tensin homolog (PTEN) is a major tumor suppressor gene and is involved in cell survival control. PTEN loss of expression (PTEN-) is associated with a poor outcome. Our study investigated the prevalence of PTEN- in terms of its characteristics and disease prognosis for lung cancer patients. Materials and Methods: In total, 167 tissue blocks from lung cancer patients at Chareonkrung Pracharak Hospital between January 2010 and December 2020 were studied through immunohistochemistry staining (IHC) for PTEN expression. The clinicopathological factors, IHC features, and epidermal growth factor receptor (EGFR) status were analyzed in association with PTEN- in term of prognosis and the overall survival (OS). Result: Adenocarcinoma was the major subtype (85.6%) and most patients (90.6%) were diagnosed at stage IV of lung cancer. The prevalence of PTEN- was 66.5%. A location at the left lower lobe (LLL) location and the absence of tumor-infiltrating lymphocytes (TILs) were significantly associated with PTEN- (p=0.039, p=0.046), while the smoking was likely correlated but not statistically significant (p=0.09). The median OS for PTEN- was not significantly different from PTEN+ (8.88 vs 7.20 months, p=0.38). However, smoking, Eastern cooperative oncology group (ECOG) status and primary symptoms were significantly associated with poorer OS. Conclusion: The prevalence of PTEN- was higher in our studies. Absent TILs and a LLL location were independent factors associated with PTEN-. However, a right upper lobe (RUL) location with PTEN- tended to have a poor prognosis. Interestingly, better survival was found in active smokers with PTEN-. Further survival studies in cases with no TILs lesions and active smokers in associations PTEN expression and other immune-related biomarkers, such as programmed death–ligand 1 (PD-L1), are warranted.

Interferon-Inducible LINC02605 Promotes Antiviral Innate Responses by Strengthening IRF3 Nuclear Translocation

Non-coding RNAs represent a class of important regulators in immune response. Previously, LINC02605 was identified as a candidate regulator in innate immune response by lncRNA microarray assays. In this study, we systematically analyzed the functions and the acting mechanisms of LINC02605 in antiviral innate immune response. LINC02605 was up-regulated by RNA virus, DNA virus, and type I IFNs in NF-κB and Jak-stat dependent manner. Overexpression of LINC02605 promotes RNA virus-induced type I interferon production and inhibited viral replication. Consistently, knockdown of LINC02605 resulted in reduced antiviral immune response and increased viral replication. Mechanistically, LINC02605 released the inhibition of hsa-miR-107 on the expression of phosphatase and tensin homolog (PTEN). By microRNA mimics and inhibitors, hsa-miR-107 was demonstrated to not only inhibit PTEN’s expression but also negatively regulate the antiviral immune response. Knockdown of LINC02605 led to the reduction of PTEN expression both in mRNA and protein levels. Overexpression of LINC02605 had an opposite impact. Moreover, LINC02605 attenuated the serine 97 phosphorylation level of interferon regulatory factor 3 (IRF3) by promoting PTEN expression. Nucleoplasmic fragmentation assay showed that knocking down LINC02605 inhibited the nuclear translocation of IRF3, rendering the host cells more susceptible to viral invasion, while overexpression showed opposite effects. Therefore, LINC02605 is an induced lncRNA by viral infection and plays a positive feedback in antiviral immune response through modulating the nuclear translocation of IRF3.

USP25 Regulates the Proliferation and Apoptosis of Ovarian Granulosa Cells in Polycystic Ovary Syndrome by Modulating the PI3K/AKT Pathway via Deubiquitinating PTEN

Background: Polycystic ovarian syndrome (PCOS) is an endocrine-related disease related to abnormal folliculogenesis and is a leading cause of infertility worldwide. Inhibition of granulosa cells (GCs) proliferation and increased GCs apoptosis have been identified as the major factors in aberrant follicle maturation.Methods: USP25 and PTEN expression in GCs from women with and without PCOS was analyzed using Western blotting. A PCOS-like mouse model was constructed using USP25 knockout and wild-type mice to explore the role of USP25 in PCOS. The human granular cell line KGN was cultured for proliferation and apoptosis assays, and the effect of USP25 on PTEN was investigated after transfection with shRNA-USP25 lentivirus.Results: USP25 expression was found to be elevated in patients and mice with PCOS. With mouse model, we observed a reduction in PCOS symptoms in mice after USP25 deletion. Increased proliferation, reduced apoptosis, activation of the phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT) signaling pathway and decreased PTEN expression were found in KGN cells after USP25 knockdown. Finally, we verified that USP25 could deubiquitinate PTEN in KGN cells.Conclusions: In this study, we investigated that USP25 can regulate the PI3K/AKT signaling pathway by deubiquitinating PTEN, thus affecting the proliferation and apoptosis of GCs and contributing to the pathogenesis of PCOS.