This study was conducted to evaluate the mechanism by which n-3 PUFA regulated the protein degradation in C2C12 myotubes. Compared with the BSA control, EPA at concentrations from 400 to 600 µM decreased total protein degradation (P < 0.01). However, the total protein degradation was decreased when the concentrations of DHA ranged from 300 µM to 700 µM (P < 0.01). DHA (400 µM, 24 h) more efficiently decreased the IκBα phosphorylation and increased in the IκBα protein level than 400 µM EPA (P < 0.01). Compared with BSA, 400 µM EPA and DHA resulted in a 47% or 68% induction of the NFκB DNA binding activity, respectively (P < 0.01). Meanwhile, 400 µM EPA and DHA resulted in a 1.3-fold and 2.0-fold induction of the PPARγ expression, respectively (P < 0.01). In C2C12 myotubes for PPARγ knockdown, neither 400 µM EPA nor DHA affected the levels of p-IκBα, total IκBα or NFκB DNA binding activity compared with BSA (P > 0.05). Interestingly, EPA and DHA both still decreased the total protein degradation, although PPARγ knockdown attenuated the suppressive effects of EPA and DHA on the total protein degradation (P < 0.01). These results revealed that DHA inhibits protein degradation more efficiently than EPA by regulating the PPARγ/NF-κB pathway in C2C12 myotubes.

Abstract. Persistent human papilloma virus (HPV) infection induces chronic inflammation resulting in human cervical cancer. However, the mechanisms underlying carcinogenesis via chronic inflammation remain largely unclear. We investigated the role of pro-inflammatory factors in epithelial-mesenchymal transition (EMT) and cancer stem cell-like (CSCL) characteristics of HeLa cells exposed to TNF-α with or without TGF-β. We then determined the role of NF-κB/Twist signal axis in the pathogenesis of cervical cancer. We found that HeLa cells exposed to TNF-α following chronic treatment with TGF-β exhibited EMT, self-renewal and high mobility. Knockdown of NF-κBp65 inhibited NF-κB and Twist1 expression, and EMT and CSCL properties of HeLa cells following co-treatment with TNF-α and TGF-β. Conversely, overexpression of NF-κBp65 potentiated the above effects. However, knockdown or overexpression of Twist1 had no effect on NF-κBp65 expression, but inhibited or promoted EMT and CSCL features. Notably, overexpression of Twist1 rescued NF-κBp65 knockdown. Our results demonstrate the role of NF-κB/Twist signaling axis in which HeLa cells treated with TNF-α following chronic exposure to TGF-β induce EMT and CSCL properties. The NF-κB/Twist signal axis may represent an effective therapeutic target in cervical cancer. IntroductionCervical cancer is a key factor associated with morbidity and mortality in women worldwide (1). Infection with human papilloma viruses (HPV) triggers carcinogenesis. Most of the precancerous lesions do not progress to invasive carcinoma, suggesting that HPV is not the only factor contributing to the development of cervical cancer (2,3). However, persistent HPV infection alters the pro-inflammatory cytokine profile, resulting in chronic inflammation and recurrence of cervical cancer (4). Cancer stem cells (CSCs) play a vital role in cancer initiation and metastasis (5). Metastasis results in treatment failure and death (6). Epithelial-mesenchymal transition (EMT) has been implicated as the key factor in CSCs transformation (7,8). EMT has been shown to induce reversion to a CSC-like phenotype, linking CSCs and EMT (9,10).NF-κB is a classic transcription factor activated by inflammatory stimuli, such as LPS (11), TNF-α (12) and IL-10 (13). Activated NF-κB induces extensive gene expression in immune response (TNF-α), angiogenesis (VEGF), invasion (MMP-9) and EMT (Twist) (14-17). Furthermore, NF-κB, a pleiotropic transcription factor, has been implicated in . In mammary epithelial cells, EMT is upregulated via overexpression of NF-κBp65 (17).The transcriptional factor TWIST mediates EMT and cancer metastasis (18,19). In uterine cancers, Twist overexpression promotes invasion and metastasis (20-23). However, the role of NF-κB/Twist axis in cervical cancer has not been investigated. In this study, we focused on the role of NF-κB/ Twist axis in vitro, by co-treatment of human cervical cancer cell line HeLa with TNF-α and TGF-β. Materials and methodsReagents. DMEM was obtained from Gibco, FBS from PAA, trypsin a...

Manganese superoxide dismutase promotes migration and invasion in lung cancer cells via upregulation of the transcription factor forkhead box M1. Here, we assessed whether upregulation of forkhead box M1 by manganese superoxide dismutase overexpression mediates the acquisition of cancer stem-like cell characteristics in non-small cell lung cancer H460 cells. The second-generation spheroids from H460 cells were used as lung cancer stem-like cells. The levels of manganese superoxide dismutase, forkhead box M1, stemness markers (CD133, CD44, and ALDH1), and transcription factors (Bmi1, Nanog, and Sox2) were analyzed by Western blot. Sphere formation in vitro and carcinogenicity of lung cancer stem-like cells were evaluated by spheroid formation assay and limited dilution xenograft assays. Knockdown or overexpression of manganese superoxide dismutase or/and forkhead box M1 by transduction with short hairpin RNA(shRNA) or complementary DNA were performed for mechanistic studies. We showed that manganese superoxide dismutase and forkhead box M1 amounts as well as the expression levels of stemness markers and transcription factors sphere formation in vitro, and carcinogenicity of lung cancer stem-like cells were higher than in monolayer cells. Lung cancer stem-like cells transduced with manganese superoxide dismutase shRNA or FoxM1 shRNA exhibited decreased sphere formation and lower amounts of stemness markers and transcription factors. Overexpression of manganese superoxide dismutase or FoxM1 in H460 cells resulted in elevated sphere formation rates and protein levels of stemness markers and transcription factors. Meanwhile, manganese superoxide dismutase knockdown or overexpression accordingly altered forkhead box M1 levels. However, forkhead box M1 knockdown or overexpression had no effect on manganese superoxide dismutase levels but inhibited or promoted lung cancer stem-like cell functions. Interestingly, forkhead box M1 overexpression alleviated the inhibitory effects of manganese superoxide dismutase knockdown in lung cancer stem-like cells. In a panel of non-small cell lung cancer cells, including H441, H1299, and H358 cells, compared to the respective monolayer counterparts, the expression levels of manganese superoxide dismutase and forkhead box M1 were elevated in the corresponding spheroids. These findings revealed the role of forkhead box M1 upregulation by manganese superoxide dismutase overexpression in maintaining lung cancer stem-like cell properties. Therefore, inhibition of forkhead box M1 upregulation by manganese superoxide dismutase overexpression may represent an effective therapeutic strategy for non-small cell lung cancer.

Adhesion molecules play vital roles in airway hyperresponsiveness (AHR) or airway inflammation. Our previous study indicated that adhesion molecule catenin alpha-like 1 (CTNNAL1) is relevant closely to asthma susceptibility, but its biological function or significance is still unclear. In the present study, we observed the temporal and spatial distribution of CTNNAL1 expression in mouse lung tissue with the OVA-sensitized asthma model and found that the level of CTNNAL1 mRNA showed a prominent negative correlation with pulmonary resistance (R(L)). To study the function of CTNNAL1 in airway, effects of CTNNAL1 on proliferation and wound repair activity of human bronchial epithelial cells (HBEC) was investigated with antisense oligonucleotide (ASO) technique. The results showed that: (1) CTNNAL1 ASO could decelerate the repairing velocity and proliferation of HBEC; (2) CTNNAL1 expression was increased on the edge cells of mechanic wounded area in culture; (3) extracellular matrix component fibronectin (Fn) obviously promoted wound repair activity and proliferation of HBEC, which could be blocked by CTNNAL1 ASO; (4) Western blot showed that Fn could promote FAK phosphorylation, which also be inhibited by CTNNAL1 ASO. In conclusion, the level of CTNNAL1 mRNA expression is highly correlated to airway resistance; CTNNAL1 may contribute to the wound repair and proliferation of HBEC. Furthermore, it may serve to Fn mediated cell-extracellular adhesion and its signal transduction.

Background Manganese superoxide dismutase (MnSOD) upregulating FoxM1 have previously been demonstrated promoting lung cancer stemness. Isovitexin exhibits antitumor activities in various cancers. This study aimed to assess whether isovitexin inhibits hepatic carcinoma stem-like cells (HCSLCs) features via regulating MnSOD and FoxM1 expression. Methods Second-generation spheres from the hepatic carcinoma cell lines, respectively, were used as HCSLCs. Protein amounts of MnSOD, FoxM1 and stemness-associated markers (CD133, CD44, ALDH1, Bmi1, Nanog and Oct4) were determined by immunoblotting. In vitro carcinogenicity was evaluated by sphere- and colony-formation assays. The effects of isovitexin on HCSLC carcinogenicity and stemness were examined in vitro and in xenograft models. An adenoviral delivery system was employed to manipulate MnSOD and/or FoxM1. Luciferase reporter assay was performed to verify isovitexin downregulated FoxM1 by inhibiting MnSOD-mediated effects of E2F1 and/or Sp1 on activation of FoxM1 promoter. Results FoxM1 upregulation by MnSOD contributed to carcinogenicity and stemness, with increased sphere- and colony-formation capabilities, upregulated stemness-associated markers and CD133 + subpopulation as well as elevated oncogenicity in vivo in HCSLCs compared with hepatic carcinoma cells. Isovitexin substantially decreased sphere and colony formation rates, and stemness-associated markers in cultured HCSLCs by suppressing MnSOD and FoxM1 expression. Importantly, isovitexin significantly inhibited tumor growth of in nude mice bearing HCSLCs and reduced CD133 protein expression of xenograft in nude mice. MnSOD or FoxM1 knockdown enhanced the effects of isovitexin suppression on carcinogenicity and stemness in HCSLC. MnSOD or FoxM1 overexpression attenuated the effects of isovitexin. Additionally, isovitexin and MnSOD knockdown could inhibit FoxM1 reporter activity via a decreased binding of E2F1 and/or Sp1 onto FoxM1 promoter. FoxM1 overexpression reversed the effects of isovitexin combined with MnSOD knockdown, without affecting MnSOD expression. Moreover, MnSOD knockdown plus thiostrepton, a FoxM1 specific inhibitor, cooperated with isovitexin to repress xenograft tumor growth and downregulate MnSOD and FoxM1 in nude mice bearing HCSLCs from MHCC97H cells. Conclusions Isovitexin inhibits carcinogenicity and stemness in HCSLCs by downregulating FoxM1via inhibition of MnSOD. Electronic supplementary material The online version of this article (10.1186/s13046-019-1244-6) contains supplementary material, which is available to authorized users.