Silencing of Xeroderma Pigmentosum Group D Gene Promotes Hepatoma Cell Growth by Reducing P53 Expression

XPD Regulates MIAT/miR-29a-3p/COL4A1 Axis to Impede Hepatocellular Carcinoma Development

Xeroderma pigmentosum group D (XPD) has been reported to inhibit cell growth of hepatocellular carcinoma (HCC). This work attempted to reveal the underlying mechanism of XPD in HCC. In this study, XPD and miR-29a-3p were down-regulated, and MIAT and COL4A1 were up-regulated in tumor tissues of HCC patients. The same phenomena were also observed in HCC cell lines. XPD overexpression enhanced E-cadherin expression, reduced N-cadherin and Vimentin expression, and repressed the migration and invasion of HepG2 and Hep3B cells. MIAT or COL4A1 overexpression reversed the effect of XPD on the invasion, migration, and epithelial-mesenchymal transition (EMT) of HCC cells. MIAT overexpression-mediated promotion of malignant phenotypes of HCC cells was reversed by COL4A1 deficiency. In terms of mechanics, MIAT enhanced COL4A1 expression by sponging miR-29a-3p. XPD interacted with P53. XPD overexpression repressed MIAT expression, which was abrogated by P53 silencing. Thus, XPD recruited P53 to repress MIAT expression. In vivo, XPD up-regulation inhibited tumor growth and reduced the metastatic lesions in intrahepatic, lung, and kidney tissues of mice. In conclusion, this study demonstrated that XPD recruited P53 to regulate the MIAT/miR-29a-3p/COL4A1 axis, which contributed to inhibiting migration, invasion, EMT, and metastasis of HCC. Thus, XPD may be a valuable target for HCC treatment.

Xeroderma Pigmentosum group D suppresses proliferation and promotes apoptosis of HepG2 cells by downregulating ERG expression via the PPARγ pathway

Xeroderma Pigmentosum group D (XPD) gene has been shown to suppress hepatocellular carcinoma (HCC) progression, but its mechanism remains not fully understood. ETS-related gene (ERG) is generally known as an oncogenic gene. This study aimed to explore whether XPD regulated HCC cell proliferation, apoptosis and cell cycle by inhibiting ERG expression via the PPARγ pathway. The human hepatoma cells (HepG2) were transfected with the XPD overexpression vector (pEGFP-N2/XPD) or empty vector (pEGFP-N2). The PPARγ inhibitor GW9662 was used to determine whether XPD effects were mediated by activation of PPARγ pathway. Cell cycle and apoptosis were ascertained by flow cytometry, and cell viability was measured by MTT assay. Reverse transcription-polymerase chain reaction and Western blot were performed to determine the mRNA and protein levels. Overexpression of XPD significantly enhanced the expression of PPARγ and p-PPARγ, whereas it downregulated that of ERG and cdk7. Furthermore, XPD overexpression notably inhibited proliferation, promoted apoptosis and decreased the percentage of cells in the S + G2 phase of HepG2 cells. However, these effects of XPD overexpression were abrogated by GW9662. Collectively, XPD suppresses proliferation and promotes apoptosis of HepG2 cells by downregulating ERG expression via activation of the PPARγ pathway.

COL4A1, negatively regulated by XPD and miR-29a-3p, promotes cell proliferation, migration, invasion and epithelial-mesenchymal transition in liver cancer cells

OBJECTIVE

Collagen type IV alpha 1 (COL4A1) exerts tumor-promoting functions in several tumors. However, its role in liver cancer remains not fully understood. Hence, this study aims to investigate the role of COL4A1 in regulating liver cancer cell behaviors and to validate its upstream regulatory mechanism.

METHODS

Expression of xeroderma pigmentosum D (XPD) and COL4A1 was examined by qRT-PCR and western blot. Cell proliferation, migration, and invasion were evaluated. The protein levels of N-cadherin, vimentin, and E-cadherin were determined by western blot to evaluate epithelial-mesenchymal transition (EMT). The interaction between miR-29a-3p and COL4A1 was analyzed by luciferase reporter assay.

RESULTS

COL4A1 overexpression significantly promoted cell proliferation, migration, invasion, and EMT in Hep3B cells. In contrast, COL4A1 silencing yielded the opposite effects in HepG2 cells. Expression of COL4A1 was increased, whereas expression of XPD and miR-29a-3p was decreased in HCC tissues compared to controls. COL4A1 mRNA level was negatively correlated with expression of XPD and miR-29a-3p in HCC tissues. Furthermore, XPD silencing-mediated up-regulation of COL4A1 expression was attenuated by miR-29a-3p mimic. Moreover, miR-29a-3p mimic inhibited Hep3B cell proliferation, migration, and invasion by directly targeting COL4A1.

CONCLUSION

COL4A1 is negatively regulated by XPD-miR-29a-3p axis and promotes liver cancer progression in vitro.

[Effects of Cullin1 on the Biological Characteristics of Lung Adenocarcinoma A549 and H1395 Cells]

BACKGROUND

Cullin1 is a representative member of the Cullin family, and it plays an important role in the ubiquitination of cell cycle, transcription and signal transduction related proteins. Cullin1 is closely related to the occurrence and development of a variety of malignant tumors. The aim of this study is to investigate the effects of Cullin1 on biological function of lung adenocarcinoma A549 and H1395 Cells.

METHODS

The expression of Cullin1 mRNA was detected by quantitative Real-time polymerase chain reaction in lung adenocarcinoma cells (A549, H358, H1395, H1650) and human normal lung epithelial cells BEAS-2B, siRNA technology was used to interfere with lung adenocarcinoma cells with relatively high expression of Cullin1 mRNA; cell proliferation, cell cycle distribution, early cell apoptosis, invasion and migration ability were detected by methyl thiazolyl tetrazolium assay (MTT), flow cytometry and Transwell experiment; Western blot was used to detect the expression levels of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinase-1 (TIMP-1), Cyclin D1, Cyclin E2, p21 and p27.

RESULTS

Compared with the BEAS-2B cell, Cullin1 mRNA was highly expressed in lung adenocarcinoma cells, especially in lung adenocarcinoma A549 and H1395 cells (P<0.05). The proliferation ability of lung adenocarcinoma cells was inhibited after interference with Cullin1, and the number of cells in G1 phase increased, the number of cells in S phase decreased, and the early apoptosis rate of lung adenocarcinoma cells is significantly increased (P<0.05); The invasion and migration ability of lung adenocarcinoma cells decreased (P<0.05). After interference with Cullin1, the protein expression of MMP-9, MMP-2, CyclinD1 and CyclinE2 decreased (P<0.05), while the expression of TIMP-1, p21 and p27 protein increased (P<0.05).

CONCLUSIONS

Interference with Cullin1 inhibits the proliferation, invasion and migration of lung adenocarcinoma A549 and H1395 cells, Cullin1 plays a role in promoting cancer in lung adenocarcinoma.