cIAP2 via NF-κB signalling affects cell proliferation and invasion in hepatocellular carcinoma

Endothelial Birc3 promotes renal fibrosis through modulating Drp1-mediated mitochondrial fission via MAPK/PI3K/Akt pathway

Renal fibrosis serves as the shared pathway in chronic kidney disease (CKD) progression towards end-stage renal disease (ESRD). Endothelial-mesenchymal transition (EndMT) is a vital mechanism leading to the generation of myofibroblasts, thereby contributing to the advancement of fibrogenesis. Baculoviral IAP Repeat Containing 3(Birc3) was identified as a crucial inhibitor of cell death and a significant mediator in inflammatory signaling and immunity. However, its involvement in the development of renal interstitial fibrosis via EndMT still needs to be clarified. Herein, elevated levels of Birc3 expression along with EndMT-associated alterations, including increased α-smooth muscle actin (α-SMA) levels and decreased CD31 expression, were observed in fibrotic kidneys of Unilateral Ureteral Obstruction (UUO)-induced mouse models and transforming growth factor-β (TGF-β)-induced EndMT in Human Umbilical Vein Endothelial Cells (HUVECs). Functionally, Birc3 knockdown inhibited EndMT and mitochondrial fission mediated by dynamin-related protein 1 (Drp1) both in vivo and in vitro. Mechanistically, endothelial Birc3 exacerbated Drp-1-induced mitochondrial fission through the MAPK/PI3K/Akt signaling pathway in endothelial cell models stimulated TGF-β. Collectively, these findings illuminate the mechanisms and indicate that targeting Birc3 could offer a promising therapeutic strategy to improve endothelial cell survival and mitigate the progression of CKD.

cIAP-2 protein is upregulated by human papillomavirus in oropharyngeal cancers: role in radioresistance in vitro

BACKGROUND

High-risk human papillomaviruses are the causal agents of a subset of head and neck cancers. A previous transcriptomic analysis showed that cIAP2 protein, involved in cell survival and apoptosis, is upregulated in OKF6 oral cells that express HPV16 E6/E7. In addition, cIAP2 promotes radioresistance, a very important concern in HNC treatment. However, cIAP2 increase has not yet been evaluated in oropharyngeal carcinomas (OPCs), nor has been the role of cIAP2 in HNC radioresistance.

METHODS

We carried out a descriptive-analytical retrospective study in 49 OPCs from Chilean patients. We determined the expression of cIAP2 at transcript and proteins levels using reverse-transcriptase -polymerase chain reaction and immunohistochemistry, respectively. HPV and p16 expression were previously analyzed in these specimens. In addition, SCC-143 HNC cells ectopically expressing HPV16 E6/E7 were analyzed for cIAP2 expression and after transfection with a siRNA for HPV16 E6/E7 knocking down.

RESULTS

We found a statistically significant association between HPV presence and cIAP2 expression (p = 0.0032 and p = 0.0061, respectively). An association between p16 and cIAP2 levels was also found (p = 0.038). When SCC-143 cells were transfected with a construct expressing HPV16 E6/E7, the levels of cIAP2 were significantly increased (p = 0.0383 and p = 0.0115, respectively). Conversely, HPV16 E6 and E7 knocking down resulted in a decrease of cIAP2 levels (p = 0.0161 and p = 0.006, respectively). Finally, cIAP2 knocking down in HPV16 E6/E7 cells resulted in increased apoptosis after exposure to radiation at 4 and 8 Gy (p = 0.0187 and p = 0.0061, respectively).

CONCLUSION

This study demonstrated for the first time a positive relationship between HPV presence and cIAP2 levels in OPCs. Additionally, cIAP2 knocking down sensitizes HNC cells to apoptosis promoted by radiation. Therefore, cIAP2 is a potential therapeutic target for radiation in HPV-driven HNC.

CircNUP54 promotes hepatocellular carcinoma progression via facilitating HuR cytoplasmic export and stabilizing BIRC3 mRNA

Circular RNAs (circRNAs) have been implicated in tumorigenesis and progression of various cancers. However, the underlying mechanisms of circRNAs in hepatocellular carcinoma (HCC) have not been fully elucidated. Herein, a new oncogenic circRNA, hsa_circ_0070039 (circNUP54), was identified to be significantly upregulated in HCC through circRNA sequencing. As verified in 68 HCC samples, circNUP54 overexpression was correlated with aggressive cancerous behaviors and poor outcomes. Moreover, the function experiments showed that knockdown of circNUP54 inhibited the malignant progression of HCC in vitro and in vivo, whereas overexpression of circNUP54 had the opposite role. Mechanistic investigations carried out by RNA pull-down, RNA immunoprecipitation, and immunofluorescence revealed that circNUP54 interacted with the RNA-binding protein Hu-antigen R (HuR) and promoted its cytoplasmic export. The cytoplasmic accumulation of HuR stabilized the downstream BIRC3 mRNA through its binding to the 3' UTR region. Consequently, the encoded protein of BIRC3, cellular inhibitor of apoptosis 2 (cIAP2), proceeded to activate the NF-κB signal pathway and ultimately contributed to HCC progression. In addition, depletion of BIRC3 rescued the pro-tumorigenic effect of circNUP54 on HCC cells. Overall, this study demonstrated that circNUP54 facilitates HCC progression via regulating the HuR/BIRC3/NF-κB axis, which may serve as a promising therapeutic target for HCC treatment.

Asperulosidic Acid Restrains Hepatocellular Carcinoma Development and Enhances Chemosensitivity Through Inactivating the MEKK1/NF-κB Pathway

Asperulosidic acid (ASPA) is a plant-extracted iridoid terpenoid with tumor-suppressive and anti-inflammatory properties. At present, the antitumor function of ASPA and its related mechanisms in hepatocellular carcinoma (HCC) cells were explored. Human normal hepatocytes HL-7702 and HCC cells (Huh7 and HCCLM3) were treated with varying concentrations (0 to 200 μg/mL) of ASPA. Cell viability, proliferation, apoptosis, migration, and invasion were checked. The expression of proteins was detected by Western blot. Furthermore, the effect of ASPA (100 μg/mL) on the sensitivity of HCC cells to chemotherapeutic agents, including doxorubicin and cisplatin, was evaluated. A subcutaneous xenografted tumor model was set up in nude mice, and the antitumor effects of ASPA were evaluated. ASPA hindered HCC cells' proliferation, migration, and invasion, and amplified their apoptosis and sensitivity to chemotherapeutic agents. Additionally, ASPA inactivated the MEKK1/NF-κB pathway. Overexpression of MEKK1 increased HCC proliferation, migration, and invasion and facilitated chemoresistance. ASPA treatment alleviated the carcinogenic effect mediated by MEKK1 overexpression. MEKK1 knockdown slowed down HCC progression. However, ASPA could not exert additional antitumor effects in MEKK1 knockdown cells. In vivo results displayed that ASPA substantially curbed tumor growth and inactivated the MEKK1/NF-κB pathway in mice. All over, ASPA exerts antitumor effects in HCC by suppressing the MEKK1/NF-κB pathway.

Dysregulation of PLOD2 Promotes Tumor Metastasis and Invasion in Hepatocellular Carcinoma

Background and Aims

Metastasis is a major factor associated with high recurrence and mortality in hepatocellular carcinoma (HCC) patients while the underlying mechanism of metastasis remains elusive. In our study, procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2) was shown to be involved in the process of metastasis in HCC.

Methods

The Cancer Genome Atlas (TCGA) database and HCC tissue microarrays were used to evaluate the expression of genes. In vitro migration, invasion, in vivo subcutaneous tumor model and in vivo lung metastasis assays were used to determine the role of PLOD2 in tumor growth and metastasis in HCC. RNA sequencing and gene set enrichment analysis were performed to uncover the downstream factor of PLOD2 in HCC cells. A luciferase reporter assay was performed to evaluate the interaction between PLOD2 and interferon regulatory factor 5 (IRF5).

Results

The expression of PLOD2 in HCC tissues was higher than that in adjacent tissues, and increased PLOD2 expression was often found in advanced tumors and was correlated with poor prognosis in HCC patients. In vitro experiments, knockdown of PLOD2 reduced the migration and invasion of human HCC cells. Loss of PLOD2 suppressed human HCC growth and metastasis in a subcutaneous tumor model and a lung metastasis model. Baculoviral IAP repeat containing 3 (BIRC3) was proven to be the downstream factor of PLOD2 in human HCC cells. In addition, PLOD2 was transcriptionally regulated by IRF5 in HCC cells.

Conclusions

High expression of PLOD2 was regulated by IRF5, which was correlated with the poor survival of HCC patients. PLOD2 enhanced HCC metastasis via BIRC3, suggesting that PLOD2 might be a valuable prognostic biomarker for HCC treatment.

Birc3 and Tip1 are upregulated in renal ischemia reperfusion injury

Identification of ischemia-reperfusion injury (I/R)-associated genes is essential for exploring I/R novel mechanisms. Previously, we screened differentially expressed genes in renal I/R mouse models and found that Tax1 binding protein 3 (Tip1) and baculoviral IAP repeat containing 3 (Birc3) are two upregulated genes in I/R. In the present study, we analyzed the expression of Tip1 and Birc3 in I/R models. We found that the expression of Tip1 and Birc3 was upregulated in I/R-treated mice, whereas Tip1 was downregulated and Birc3 was upregulated in oxygen-glucose deprivation/reoxygenation (OGD/R) in vitro models. By inhibiting Birc3 with AT-406 in I/R-treated mice, we observed that the serum creatinine or blood urea nitrogen did not vary. However, inhibition of Birc3 enhanced apoptosis of kidney tissues induced by I/R treatment. Consistently, we found that inhibition of Birc3 also increased the apoptosis rate in tubular epithelial cells induced by OGD/R. These data demonstrated that Tip1 and Birc3 were upregulated in I/R injury. The upregulation of Birc3 may protect against renal I/R injury.

Ubiquitin-specific protease 35 (USP35) mediates cisplatin-induced apoptosis by stabilizing BIRC3 in non-small cell lung cancer

Ubiquitin-specific protease 35 (USP35) is a member of the ubiquitin-specific protease family (USP), which influences the progression of multiple cancers by deubiquitinating a variety of substrates. In recent years, the specific role of USP35 was begun to be understood. In this study, we investigated the role and underlying molecular mechanisms of USP35 in chemoresistance of non-small cell lung cancer (NSCLC) to cisplatin. Depletion of USP35 increased the sensitivity of NSCLC to cisplatin-induced apoptosis. We screened and identified a potential substrate of USP35, baculoviral IAP repeat containing 3 (BIRC3). Overexpression of USP35 in H460 cells increased the abundance of BIRC3, while USP35 knockdown in Anip973 cells decreased BIRC3 abundance. Notably, USP35 directly interacted with and stabilized BIRC3 through lys48-mediated polyubiquitination via its deubiquitinating enzyme activity. USP35 alleviated cisplatin-induced cell apoptosis by regulating BIRC3 levels in NSCLC cells. Moreover, a significant positive correlation between USP35 and BIRC3 protein expression levels was observed in human NSCLC tissues. Taken together, USP35 plays a vital role in resistance to cisplatin-induced cell death through the overexpression of BIRC3. USP35 might be a potentially novel therapeutic target in human NSCLC.