EZH2 suppresses ferroptosis in hepatocellular carcinoma and reduces sorafenib sensitivity through epigenetic regulation of TFR2.

Enhancing sensitivity to sorafenib can significantly extend the duration of resistance to it, offering substantial benefits for treating patients with hepatocellular carcinoma (HCC). However, the role of ferroptosis in influencing sorafenib sensitivity within HCC remains pivotal. The enhancer of zeste homolog 2 (EZH2) plays a significant role in promoting malignant progression in HCC, yet the relationship between ferroptosis, sorafenib sensitivity, and EZH2 is not entirely clear. Bioinformatic analysis indicates elevated EZH2 expression in HCC, predicting an unfavorable prognosis. Overexpressing EZH2 can drive HCC cell proliferation while simultaneously reducing ferroptosis. Further analysis reveals that EZH2 amplifies the modification of H3K27 me3, thereby influencing TFR2 expression. This results in decreased RNA polymerase II binding within the TFR2 promoter region, leading to reduced TFR2 expression. Knocking down EZH2 amplifies sorafenib sensitivity in HCC cells. In sorafenib-resistant HepG2(HepG2-SR) cells, the expression of EZH2 is increased. Moreover, combining tazemetostat-an EZH2 inhibitor-with sorafenib demonstrates significant synergistic ferroptosis-promoting effects in HepG2-SR cells. In conclusion, our study illustrates how EZH2 epigenetically regulates TFR2 expression through H3K27 me3, thereby suppressing ferroptosis. The combination of the tazemetostat with sorafenib exhibits superior synergistic effects in anticancer therapy and sensitizes the HepG2-SR cells to sorafenib, shedding new light on delaying and ameliorating sorafenib resistance.

BMP2 as a promising anticancer approach: functions and molecular mechanisms.

Bone morphogenetic protein 2 (BMP2), a pluripotent factor, is a member of the transforming growth factor-beta (TGF-ß) superfamily and is implicated in embryonic development and postnatal homeostasis in tissues and organs. Experimental research in the contexts of physiology and pathology has indicated that BMP2 can induce macrophages to differentiate into osteoclasts and accelerate the osteolytic mechanism, aggravating cancer cell bone metastasis. Emerging studies have stressed the potent regulatory effect of BMP2 in cancer cell differentiation, proliferation, survival, and apoptosis. Complicated signaling networks involving multiple regulatory proteins imply the significant biological functions of BMP2 in cancer. In this review, we comprehensively summarized and discussed the current evidence related to the modulation of BMP2 in tumorigenesis and development, including evidence related to the roles and molecular mechanisms of BMP2 in regulating cancer stem cells (CSCs), epithelial-mesenchymal transition (EMT), cancer angiogenesis and the tumor microenvironment (TME). All these findings suggest that BMP2 may be an effective therapeutic target for cancer and a new marker for assessing treatment efficacy.

Human Papillomavirus E6/E7 and Long Noncoding RNA TMPOP2 Mutually Upregulated Gene Expression in Cervical Cancer Cells.

TMPOP2 was previously suggested to be an oncogenic long noncoding RNA which is excessively expressed in cervical cancer cells and inhibits E-cadherin gene expression by recruiting transcription repressor EZH2 to the gene promoter. So far, the function and regulation of TMPOP2 in cervical cancer remain largely unknown. Herein, we found that TMPOP2 expression was correlated with human papillomavirus 16/18 (HPV16/18) E6 and E7 in cervical cancer cell lines CaSki and HeLa. Tumor suppressor p53, which is targeted for degradation by HPV16/18, was demonstrated to associate with two p53 response elements in the TMPOP2 promoter to repress the transcription of the TMPOP2 gene. Reciprocally, ectopic expression of TMPOP2 was demonstrated to sequester tumor repressor microRNAs (miRNAs) miR-375 and miR-139 which target HPV16/18 E6/E7 mRNA and resulted in an upregulation of HPV16/18 E6/E7 genes. Thereby, HPV16/18 E6/E7 and the long noncoding RNA (lncRNA) TMPOP2 form a positive feedback loop to mutually derepress gene expression in cervical cancer cells. Moreover, results of RNA sequencing and cell cycle analysis showed that knockdown of TMPOP2 impaired the expression of cell cycle genes, induced cell cycle arrest, and inhibited HeLa cell proliferation. Together, our results indicate that TMPOP2 and HPV16/18 E6/E7 mutually strengthen their expression in cervical cancer cells to enhance tumorigenic activities.IMPORTANCE Human papillomaviruses 16 and 18 (HPV16/18) are the main causative agents of cervical cancer. Viral proteins HPV16/18 E6 and E7 are constitutively expressed in cancer cells to maintain oncogenic phenotypes. Accumulating evidences suggest that HPVs are correlated with the deregulation of long noncoding RNAs (lncRNAs) in cervical cancer, although the mechanism was unexplored in most cases. TMPOP2 is a newly identified lncRNA excessively expressed in cervical cancer. However, the mechanism for the upregulation of TMPOP2 in cervical cancer cells remains largely unknown and its relationship with HPVs is still elusive. The significance of our research is in revealing the mutual upregulation of HPV16/18 E6/E7 and TMPOP2 with the molecular mechanisms explored. This study will expand our understandings of the oncogenic activities of human papillomaviruses and lncRNAs.

[Myricetin reduces the reproductive toxicity of cyclophosphamide in male mice].

OBJECTIVE: To explore the effect of myrica flavone on male reproductive toxicity induced by cyclophosphamide and its mechanism. METHODS: Thirty 6-week-old male ICR mice were randomly divided into 5 groups: blank control group, cyclophosphamide reproductive injury model group, myricetin low-medium high-dose intervention group. Except the blank control group, the other groups were intraperitoneally injected with cyclophosphamide 50 mg/kg daily for 7 consecutive days. The myricetin group received intragastric administration of 100, 200, and 400 mg/kg myricetin daily for 30 consecutive days since the second day of modeling. The blank control group and the model control group were given an equal volume of a 0. 25% sodium carboxymethyl cellulose solution. The body weight was measured every 3 days, and the day after the last administration, the mice were sacrificed by cervical dislocation, and the epididymis and testes were quickly taken. Testicular weighing, testicular index calculation, epididymis to obtain sperm, sperm analyzer to analyze sperm density and vitality. The expression of Bax and Bcl-2 in testicular tissues was detected by immunoblotting, and the mitochondrial membrane potential of sperm was detected by flow cytometry. RESULTS: After 9 days of modeling, the weight of mice in the model group was lower than that of the blank control group, which was statistically different(P<0. 05). There was no difference between the myricetin treatment group and the model group. The testis index of the model group was(3. 93±0. 91)mg/g, which was significantly lower than that of the blank control group(6. 93±0. 98)mg/g, and the difference was statistically significant(P<0. 05). After treatment with bayberry flavonoids, the testis index increased, in the 100 and 200 groups and 400 mg/kg testis index were(3. 94±1. 21) mg/g, (4. 33±0. 88) mg/g, and(4. 80±0. 43) mg/g, respectively. Compared with model control group, The difference was statistically significant(P<0. 05 and P<0. 01). Compared with the control group, the sperm density, sperm rate of forward movement, sperm rate of non-forward movement, and decreased sperm rate of non-moving sperm increased in the model group. After treatment with bayberry flavonoids, compared with the model group, the sperm density, sperm rate of forward motion, and sperm rate of non-forward motion increased, and the immobility sperm rate decreased. The 200 and 400 mg/kg groups had statistical significance(P<0. 05 or P<0. 01); the normal rate of sperm mitochondrial membrane potential in the model group was(54. 70±5. 45)%, and the normal mitochondrial membrane potential rate after treatment with myricetin of 100, 200 and 400 mg/kg(59. 10±9. 97)%, (62. 10±6. 07)% and(77. 10±8. 87)%, of which the 400 mg/kg group was statistically significant(P<0. 05); the ratio of Bax/Bcl-2 in the model group was 5. 92±1. 45, and the ratio of Bax/Bcl-2 decreased after treatment with myricetin of 100, 200 and 400 mg/kg, which were 2. 52±0. 51, 1. 71±0. 52 and 1. 07±0. 29. There were statistical differences(P<0. 05 or P<0. 01). CONCLUSION: Myrica flavone can protect sperm mitochondrial membrane potential, inhibit testicular cell apoptosis, and protect the male mice from reproductive toxicity induced by cyclophosphamide.

Transcriptional factors p300 and MRTF-A synergistically enhance the expression of migration-related genes in MCF-7 breast cancer cells.

The transcriptional coactivator p300 is highly expressed in breast cancer tissues. MRTF-A is a transcription factor governed by the Rho-GTPase-actin signaling pathway. The purpose of this study was to explore the role of p300 in breast cancer metastasis. Here we showed that the motility of breast cancer cells was enhanced by the overexpression of p300, meanwhile, the transcription of migration-related genes was upregulated. Depletion of p300 downregulated the migration-related genes and slowed down the migration of breast cancer cells. p300 worked synergistically with MRTF-A to activate the transcription of MYH9, MYL9 and CYR61. As identified by co-IP, p300 interacted with the C-terminal TAD domain of MRTF-A. And together with MRTF-A, p300 was associated with the target gene promoters. Furthermore, MRTF-A was found to be acetylated in MCF-7 breast cancer cells. These results demonstrated the involvement of p300 in the MRTF-A mediated gene regulation and breast cancer cell migration.

Downregulated lncRNA SNHG18 Suppresses the Progression of Hepatitis B Virus-Associated Hepatocellular Carcinoma and Meditates the Antitumor Effect of Oleanolic Acid.

PURPOSE: Oleanolic acid (OA) has been widely reported to possess antitumor effects, but the specific molecular mechanism underlying its inhibition of hepatocellular carcinoma (HCC) progression remains unclear. This study aims to uncover the mechanism of OA antitumor effect on HBV-associated HCC and identify a potential biomarker for tumor progression. PATIENTS AND METHODS: The effect of OA on major cellular processes of HBV-associated HCC cells was evaluated by CCK8 and Transwell assay. The potential molecular mechanism was assessed by cell transfection. This study also enrolled 111 HCC patients infected with HBV to evaluate the prognostic potential of lncRNA SNHG18 (SNHG18) in HBV-associated HCC. RESULTS: The inhibitory effect of OA was observed in the critical cellular processes of HBV-associated HCC cells, which depend on OA concentration. Downregulated SNHG18 in HBV-associated HCC was demonstrated to be involved in disease development and predict patients' prognosis. The downregulation of SNHG18 dramatically promoted cellular processes of HBV-associated HCC could reverse the inhibitory effect of OA. CONCLUSION: SNHG18 served as a tumor suppressor and prognostic biomarker of HBV-associated HCC. Enhancing SNHG18 might be the mechanism underlying the antitumor effect of OA in HBV-associated HCC.

Hesperetin Inhibits TGF-ß1-Induced Migration and Invasion of Triple Negative Breast Cancer MDA-MB-231 Cells via Suppressing Fyn/Paxillin/RhoA Pathway.

Triple-negative breast cancer is an aggressive subtype of breast cancer with poor clinical outcomes and poor prognosis. Hesperetin is an active component extracted from Citrus fruits and Traditional Chinese Medicine has a wide range of pharmacological effects. Here, we assessed the anti-migration and anti-invasive effects and explored inhibitory mechanisms of hesperetin on metastasis of human triple negative breast cancer MDA-MB-231 cells. Cell viability experiments revealed that 200 µM hesperetin has a clear inhibitory effect on MDA-MB-231 cells. TGF-ß1 treatment induces apparent tumor progression in MDA-MB-231 cells including aberrant wound-healing and invasion ability, which is effectively suppressed by hesperetin co-treatment. Additionally, hesperetin inhibited the TGF-ß1-mediated actin stress fiber formation. Western blot results showed that hesperetin suppressed the TGF-ß1-mediated (i) activation of Fyn, (ii) phosphorylation of paxillin at Y31, Y88, and Y118 sites, (iii) the increased expression of RhoA, and (iv) activation of Rho-kinase. We demonstrated the increased interaction of Fyn with paxillin and RhoA protein in the TGF-ß1-induced metastasis of MDA-MB-231 cells. Small interfering RNA Fyn inhibited phosphorylation of paxillin (Y31) and activation of Rho-kinase induced by TGF-ß1. In conclusion, hesperetin has a significant inhibitory effect on migration and invasion of MDA-MB-231 cells induced by TGF-ß1, which might be attributed to inhibiting the Fyn/paxillin/RhoA pathway.

Tip60 and p300 function antagonistically in the epigenetic regulation of HPV18 E6/E7 genes in cervical cancer HeLa cells.

BACKGROUND: High-risk HPV is a causative factor of cervical cancer. HPV DNA fragments integrate into host genome resulting in the constitutive expression of HPV genes E6 and E7 under the regulation of transcription factors, such as p300 and Tip60. Interestingly, Tip60, a factor with HAT (histone acetyl transferase) activity, represses HPV18 E6/E7 genes while another HAT p300 activates the transcription of HPV18 E6/E7. OBJECTIVE: To explore the mechanism for the opposite roles of Tip60 and p300 in the virus gene regulation, and the influence of Tip60 and p300 in histone modifications in the regulatory sequence of HPV18 genes. METHODS: Tip60 or p300 was either knocked down or overexpressed in HeLa cells. The effects on HPV E6E7 expression were determined with RT-qPCR. The association of RNA polymerase II and the enrichment of acetylated or methylated histones in HPV promoter region were measured by ChIP assays with specific antibodies. RESULTS: ChIP results showed that Tip60 and p300 differently affected the modifications of histone H3K9 and the deposition of nucleosomes in HPV18 long control region (LCR). HPV18 LCR in HeLa cells is bivalent chromatin carrying both the active histone H3K9 acetylation mark and the repressive histone H3K9 trimethylation mark, the balance is maintained by Tip60 and p300. CONCLUSION(S): Based on the roles of Tip60 and p300 in HPV gene regulation, chemical compounds targeting Tip60 or p300 are potential anti-cervical cancer drugs.

Transcription of HOTAIR is regulated by RhoC-MRTF-A-SRF signaling pathway in human breast cancer cells.

HOTAIR is a long non-coding RNA highly expressed in cancer tissues and is a negative prognostic factor, whereas the mechanism by which HOTAIR expression is upregulated in cancers remains elusive. In the present study, the regulation of HOTAIR transcription was investigated in breast cancer cells MCF7 and T47D. We found that, when the RhoC-ROCK signaling was disturbed by specific siRNAs or chemical inhibitors, the expression of HOTAIR would be down-regulated. Further, MRTF-A and SRF were found to affect HOTAIR expression. HOTAIR promoter activity was demonstrated to be regulated by the RhoC-MRTF-A-SRF signaling in a CArG-box-dependent manner. Moreover, MRTF-A was identified to physically interact with HOTAIR promoter, and RNA polymerase II association on HOTAIR promoter was enhanced by MRTF-A overexpression. Taken together, our results suggest that HOTAIR is regulated by the RhoC-MRTF-A-SRF signaling pathway in breast cancer cells.

Selective p300 inhibitor C646 inhibited HPV E6-E7 genes, altered glucose metabolism and induced apoptosis in cervical cancer cells.

High risk HPV infection is a causative factor of cervical cancer. The constitutive expression of HPV E6-E7 genes is important for the maintenance of cancer phenotypes. The cellular transcription co-activator p300 plays a crucial role in the regulation of HPV genes thus it was targeted for the inhibition of HPV-associated cervical cancer. In the present study, HPV positive cervical cells were treated with C646, a selective inhibitor of p300, to investigate its influence on HPV E6-E7 expression and cancer cell growth. Results of RT-qPCR, Western-blot and promoter activity assays showed that C646 inhibited the transcription of HPV E6-E7, which was accompanied with the accumulation of p53 protein. Meanwhile, cell proliferation was suppressed, glucose metabolism was disrupted and apoptosis was induced via the intrinsic pathway. Generally, the anti-cervical cancer potential of C646 was demonstrated and a novel mechanism was proposed in this study.