UBE2M Drives Hepatocellular Cancer Progression as a p53 Negative Regulator by Binding to MDM2 and Ribosomal Protein L11

Negative Regulation of CPSF6 Suppresses the Warburg Effect and Angiogenesis Leading to Tumor Progression Via c-Myc Signaling Network: Potential Therapeutic Target for Liver Cancer Therapy

In this study, we explored the oncogenic mechanism of cleavage and polyadenylation-specific factor 6 (CPSF6) in hepatocellular carcinoma (HCC). CPSF6 was overexpressed in HCC tissues with poor survival rates compared to normal tissues. Hence, CPSF6 depletion suppressed cell viability and colony formation, induced apoptosis via PARP cleavage, and increased the sub-G1 population of Hep3B and Huh7 cells. In addition, CPSF6 enhanced the stability of c-Myc via their binding through nuclear co-localization by binding to c-Myc at the site of 258-360. Furthermore, c-Myc degradation by CPSF6 depletion was disturbed by FBW7 depletion or treatment with the proteasomal inhibitor MG132. Additionally, CPSF6 depletion suppressed the Warburg effect by inhibiting glucose, HK2, PKM2, LDH, and lactate; showed a synergistic effect with Sorafenib in Hep3B cells; and inhibited angiogenesis by tube formation and CAM assays, along with decreased expression and production of vascular endothelial growth factor (VEGF). Notably, CPSF6 depletion attenuated PD-L1 expression and increased Granzyme B levels, along with an increase in the percentage of CD4/CD8 cells in the splenocytes of BALB/c nude mice bearing Hep3B cells. Consistently, immunohistochemistry showed that CPSF6 depletion reduced the growth of Hep3B cells in BALB/c mice in orthotopic and xenograft tumor models by inhibiting tumor microenvironment-associated proteins. Overall, these findings suggest that CPSF6 enhances the Warburg effect for immune escape and angiogenesis, leading to cancer progression via c-Myc, mediated by the HK, PD-L1, and VEGF networks, with synergistic potential with sorafenib as a molecular target for liver cancer therapy.

RPL24 as a potential prognostic biomarker for cervical cancer treated by Cisplatin and concurrent chemoradiotherapy

Cervical carcinoma (CC) is the one of most common gynecologic cancers worldwide. The ribosomal proteins (RPs) are essential for ribosome assembly and function, and it has been verified that the abnormal expression of RPs was closely associated with tumorigenesis. In this study, we found that the RP large subunit 24 (RPL24) expression level was upregulated after the CC cell lines SiHa and HeLa were treated with Cisplatin (CDDP) in vitro. Simultaneously, a nude mouse xenograft model was used to examine the effect of RPL24 on tumor growth in vivo, which showed that overexpression of RPL24 can suppress tumor growth. Furthermore, we proved that RPL24 expression increased after CC patients were treated with concurrent chemoradiotherapy (CCRT), and the higher expression of RPL24 predicted a better prognosis using clinical data from 40 CC patients, verified via the Kaplan-Meier Plotter and LOGpc. These results revealed that RPL24 can be considered a potential biomarker to predict the prognosis of CC patients and assess CCRT efficacy.

Apoptotic and anti-Warburg effect of Morusin via ROS mediated inhibition of FOXM1/c-Myc signaling in prostate cancer cells

Though Morusin is known to induce apoptotic, antiprolifertaive, and autophagic effects through several signaling pathways, the underlying molecular mechanisms of Morusin still remain unclear until now. To elucidate antitumor mechanism of Morusin, cytotoxicity assay, cell cycle analysis, Western blotting, TUNEL assay, RNA interference, immunofluorescense, immunoprecipitation, reactive oxygen species (ROS) measurement, and inhibitor study were applied in this study. Morusin enhanced cytotoxicity, increased the number of TUNEL positive cells, sub-G1 population and induced the cleavages of PARP and caspase3, attenuated the expression of HK2, PKM2, LDH, c-Myc, and Forkhead Box M1 (FOXM1) along with the reduction of glucose, lactate, and ATP in DU145 and PC3 cells. Furthermore, Morusin disrupted the binding of c-Myc and FOXM1 in PC-3 cells, which was supported by String and cBioportal database. Notably, Morusin induced c-Myc degradation mediated by FBW7 and suppressed c-Myc stability in PC3 cells exposed to MG132 and cycloheximide. Also, Morusin generated ROS, while NAC disrupted the capacity of Morusin to reduce the expression of FOXM1, c-Myc, pro-PARP, and pro-caspase3 in PC-3 cells. Taken together, these findings provide scientific evidence that ROS mediated inhibition of FOXM1/c-Myc signaling axis plays a critical role in Morusin induced apoptotic and anti-Warburg effect in prostate cancer cells. Our findings support scientific evidence that ROS mediated inhibition of FOXM1/c-Myc signaling axis is critically involved in apoptotic and anti-Warburg effect of Morusin in prostate cancer cells.

NEDD8-conjugating enzyme E2s: critical targets for cancer therapy

NEDD8-conjugating enzymes, E2s, include the well-studied ubiquitin-conjugating enzyme E2 M (UBE2M) and the poorly characterized ubiquitin-conjugating enzyme E2 F (UBE2F). UBE2M and UBE2F have distinct and prominent roles in catalyzing the neddylation of Cullin or non-Cullin substrates. These enzymes are overexpressed in various malignancies, conferring a worse overall survival. Targeting UBE2M to influence tumor growth by either modulating several biological responses of tumor cells (such as DNA-damage response, apoptosis, or senescence) or regulating the anti-tumor immunity holds strong therapeutic potential. Multiple inhibitors that target the interaction between UBE2M and defective cullin neddylation protein 1 (DCN1), a co-E3 for neddylation, exhibit promising anti-tumor effects. By contrast, the potential benefits of targeting UBE2F are still to be explored. It is currently reported to inhibit apoptosis and then induce cell growth; hence, targeting UBE2F serves as an effective chemo-/radiosensitizing strategy by triggering apoptosis. This review highlights the most recent advances in the roles of UBE2M and UBE2F in tumor progression, indicating these E2s as two promising anti-tumor targets.

MiR-302c-5p affects the stemness and cisplatin resistance of nasopharyngeal carcinoma cells by regulating HSP90AA1

Nasopharyngeal carcinoma (NPC) is one of the most frequent malignant tumors diagnosed in China. Cisplatin is one of the most commonly used anticancer drugs containing platinum in combined chemotherapy. The molecular mechanism of NPC is still largely unknown, and we aim to spare no effort to elucidate it. Normal human nasopharyngeal epithelial cells and NPC cell lines were cultured. The expression levels of miR-302c-5p and HSP90AA1 were detected with quantitative real-time PCR. Western blotting was used to analyze levels of the HSP90AA1, protein kinase B (AKT), p-AKT, CD44 and SOX2 proteins. The interaction between miR-302c-5p and HSP90AA1 was detected using a luciferase reporter assay. The bicinchoninic acid assay was used to observe cisplatin resistance in NPC cells. Our records confirmed that the expression of miR-302c-5p was substantially reduced and HSP90AA1 was increased in NPC cells. Additionally, miR-302c-5p inhibited cisplatin resistance and the traits of stem cells in NPC. A luciferase assay confirmed that miR-302c-5p is bound to HSP90AA1. Overexpression of HSP90AA1 may reverse the effects of overexpressed miR-302c-5p and inhibit cisplatin resistance and stem cell traits of NPC. This study investigated whether miR-302c-5p inhibited the AKT pathway by regulating HSP90AA1 expression and altered the resistance of NPC cells to cisplatin and the traits of tumor stem cells, which has not yet been reported.

Integrative Analysis and Experimental Validation Indicated That SNHG17 Is a Prognostic Marker in Prostate Cancer and a Modulator of the Tumor Microenvironment via a Competitive Endogenous RNA Regulatory Network

The incidence of prostate cancer (PC) is growing rapidly worldwide, and studies uncovering the molecular mechanisms driving the progression and modulating the immune infiltration and antitumor immunity of PC are urgently needed. The long noncoding RNA SNHG family has been recognized as a prognostic marker in cancers and contributes to the progression of multiple cancers, including PC. In this study, we aimed to clarify the prognostic values and underlying mechanisms of SNHGs in promoting the progression and modulating the tumor microenvironment of PC through data mining based on The Cancer Genome Atlas (TCGA) database. We identified that within the SNHG family, SNHG17 was most correlated with the overall survival of PC patients and could act as an independent predictor. Moreover, we constructed a competitive endogenous RNA (ceRNA) network by which SNHG17 promotes progression and potentially inhibits the immune infiltration and immune response of prostate cancer. By interacting with miR-23a-3p/23b-3p/23c, SNHG17 upregulates the expression of UBE2M and OTUB1, which have been demonstrated to play critical roles in the tumorigenesis of human cancers, more importantly promoting cancer cell immunosuppression and resistance to cytotoxic stimulation. Finally, we examined the correlation between SNHG17 expression and the clinical progression of PC patients based on our cohort of 52 PC patients. We also verified the SNHG17/miR-23a/OTUB1 axis in RV-1 and PC-3 cells by dual luciferase and RIP assays, and we further identified that SNHG17 promoted cellular invasive capacity by modulating OTUB1. In summary, the current study conducted a ceRNA-based SNHG17-UBE2M/OTUB1 axis and indicated that SNHG17 might be a novel prognostic factor associated with the progression, immunosuppression, and cytotoxic resistance of PC.

A review on cullin neddylation and strategies to identify its inhibitors for cancer therapy

The cullin-RING E3 ligases (CRLs) are the biggest components of the E3 ubiquitin ligase protein family, and they represent an essential role in various diseases that occur because of abnormal activation, particularly in tumors development. Regulation of CRLs needs neddylation, a post-translational modification involving an enzymatic cascade that transfers small, ubiquitin-like NEDD8 protein to CRLs. Many previous studies have confirmed neddylation as an enticing target for anticancer drug discoveries, and few recent studies have also found a significant increase in advancement in protein neddylation, including preclinical and clinical target validation to discover the neddylation inhibitor compound. In the present review, we first presented briefly the essence of CRLs' neddylation and its control, systematic analysis of CRLs, followed by the description of a few recorded chemical inhibitors of CRLs neddylation enzymes with recent examples of preclinical and clinical targets. We have also listed various structure-based pointing of protein-protein dealings in the CRLs' neddylation reaction, and last, the methods available to discover new inhibitors of neddylation are elaborated. This review will offer a concentrated, up-to-date, and detailed description of the discovery of neddylation inhibitors.