Lentivirus-mediated knockdown of M-phase phosphoprotein 8 inhibits proliferation of colon cancer cells

Keep quiet: the HUSH complex in transcriptional silencing and disease

The human silencing hub (HUSH) complex is an epigenetic repressor complex whose role has emerged as an important guardian of genome integrity. It protects the genome from exogenous DNA invasion and regulates endogenous retroelements by recruiting histone methyltransferases catalyzing histone 3 lysine 9 trimethylation (H3K9me3) and additional proteins involved in chromatin compaction. In particular, its regulation of transcriptionally active LINE1 retroelements, by binding to and neutralizing LINE1 transcripts, has been well characterized. HUSH is required for mouse embryogenesis and is associated with disease, in particular cancer. Here we provide insights into the structural and biochemical features of the HUSH complex. Furthermore, we discuss the molecular mechanisms by which the HUSH complex is recruited to specific genomic regions and how it silences transcription. Finally, we discuss the role of HUSH complex members in mammalian development, antiretroviral immunity, and diseases such as cancer.

MPP8 Governs the Activity of the LIF/STAT3 Pathway and Plays a Crucial Role in the Differentiation of Mouse Embryonic Stem Cells

Mouse embryonic stem cells (mESCs) possess the remarkable characteristics of unlimited self-renewal and pluripotency, which render them highly valuable for both fundamental research and clinical applications. A comprehensive understanding of the molecular mechanisms underlying mESC function is of the utmost importance. The Human Silence Hub (HUSH) complex, comprising FAM208A, MPP8, and periphilin, constitutes an epigenetic silencing complex involved in suppressing retroviruses and transposons during early embryonic development. However, its precise role in regulating mESC pluripotency and differentiation remains elusive. In this study, we generated homogenous miniIAA7-tagged Mpp8 mouse ES cell lines. Upon induction of MPP8 protein degradation, we observed the impaired proliferation and reduced colony formation ability of mESCs. Furthermore, this study unveils the involvement of MPP8 in regulating the activity of the LIF/STAT3 signaling pathway and Nanog expression in mESCs. Finally, we provide compelling evidence that degradation of the MPP8 protein impairs the differentiation of mESC.

MPP8 Promotes Proliferation and Restrains Apoptosis in Osteosarcoma by Regulating p38αMAPK Pathway

Osteosarcoma is the most common primary bone malignancy. We aim to investigate that role of M-phase phosphoprotein 8 (MPP8) on proliferation and apoptosis in osteosarcoma. Briefly, the current research reported an in vitro study investigating the role MPP8 in OS tumorigenesis. Consequently, we found that the MPP8 expression was upregulated in osteosarcoma tissues and in osteosarcoma cell lines. Interestingly, MPP8 knockdown via shRNA restrained the cell viability and proliferation of U2OS and Saos-2 cells. In addition, MPP8 knockdown promoted the apoptosis of U2OS and Saos-2 cells, while MPP8 overexpression promotes proliferation and inhibited the cell apoptosis of osteosarcoma cells. These results suggested that MPP8 may serve as a contributor for osteosarcoma growth and inhibition of MPP8 may help restrain the development of osteosarcoma. Importantly, we found that MPP8 overexpression suppressed the protein levels of HOXA5, p38αMAPK, increased cell proliferation and inhibited cell apoptosis, while co-transfection with HOXA5 overexpression suppressed the cell proliferation and increased cell apoptosis. These results indicated that MPP8 contributed to cell proliferation and the underlying mechanism might be involved with HOXA5/ p38αMAPK pathway.

M-Phase Phosphoprotein 9 upregulation associates with poor prognosis and activates mTOR signaling in gastric cancer

The function of M-Phase Phosphoprotein 9 (MPHOSPH9) has not been investigated in gastric cancer yet. In the present study, the public cancer databases Oncomine and TCGA were analyzed, and MPHOSPH9 was found upregulated in gastric cancer tumor tissues. Immunohistochemistry (IHC) was also carried out to further confirm the results, and IHC analysis showed MPHOSPH9 was elevated in tumor tissues compared with the paracancerous tissues. QRT-PCR analysis also revealed that MPHOSPH9 mRNA was upregulated in gastric cancer cell lines. In addition, Kaplan-Meier estimates showed gastric cancer patients with high MPHOSPH9 level predicted a poor prognosis. Then, Western blot and CCK-8 assay showed overexpressed MPHOSPH9 enhanced gastric cancer cell proliferation, but MPHOSPH9 knockdown suppressed gastric cancer cell proliferation. Additionally, Western blot showed that MPHOSPH9 regulated the activation of mTOR, and overexpressed MPHOSPH9 reduced the inhibitory effects of mTOR inhibitors on cell survival in gastric cancer cells. Taken together, our results suggested that MPHOSPH9 .could be an oncogene in gastric cancer by regulating mTOR signaling.

MLPH Accelerates the Epithelial-Mesenchymal Transition in Prostate Cancer

INTRODUCTION

Prostate cancer (PC) is the second greatest cause of cancer deaths globally. PC presents a poor prognosis once it metastasizes. There is considerable proof of vital epithelial-mesenchymal transition (EMT) functionality in PC metastasis. Previous studies revealed that melanophilin (MLPH) is associated with PC; however, its role in PC remains poorly understood.

METHODS

Bioinformatics analyses were performed. The cellular responses to MLPH knockdown were examined in HCC cell lines via wound healing assay, migration and invasion assay, Western blotting.

RESULTS

Analysis of the PROGgeneV2 database revealed that high MLPH expression might indicate poor overall survival. MLPH knockdown reduced PC cell migration, proliferation, and invasion. MLPH downregulation in vivo resulted in a lower growth rate and fewer metastatic nodules in lung tissues. Furthermore, MLPH knockdown recovered downregulated expression of the mesenchymal marker N-cadherin and the epithelial marker E-cadherin following a decrease in β-catenin.

CONCLUSION

These results indicate that progression of PC is stimulated via MLPH-dependent initiation of the EMT.

M-phase phosphoprotein 8 promotes gastric cancer growth and metastasis via p53/Bcl-2 and EMT-related signaling pathways

BACKGROUND

The main issue of this study is to demonstrate whether M-phase phosphoprotein 8 (MPP8) affect gastric tumor growth and metastasis.

METHODS

Retrospective study was proceeded in 280 patients' surgical specimens with different disease stages. Loss-of-function assays, including 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide, flow cytometry, and transwell assays were performed to evaluate the biological function of MPP8 in gastric cancer cells. Apoptosis and metastasis relative biomarkers were measured by quantitative real-time polymerase chain reaction and Western blot analysis.

RESULTS

Compared with normal adjacent tissues, obviously elevated MPP8 expression was found in gastric cancer tissues. Elevated MPP8 expression was associated with male sex (vs female sex), intermediate differentiation (vs poorly differentiated cancer), and later stage (vs earlier stage). Furthermore, MPP8 overexpression in tumor tissues was marginally associated with a poor prognosis, with a significant relationship between MPP8 overexpression and prognosis among patients with poorly differentiated gastric cancer. Inhibition of MPP8 in these cells significantly suppressed proliferation and colony formation, promoted apoptosis, and repressed invasion. Furthermore, silencing of MPP8 remarkably increased apoptosis-related proteins (p53, Bax, and PARP) expression, but downregulated Bcl-2 expression. Silencing of MPP8 also decreased the expression of metastasis pathway-related proteins (N-cadherin and vimentin), and as well as the levels of anti-oncogene ZEB1, MET, and KRAS mRNA.

CONCLUSION

Our findings demonstrated that MPP8 might be an oncogene by positively regulating gastric cancer cell function through the p53/Bcl-2 and epithelial to mesenchymal transition-related signaling pathways.

INTS8 accelerates the epithelial-to-mesenchymal transition in hepatocellular carcinoma by upregulating the TGF-β signaling pathway

Background

Hepatocellular carcinoma (HCC) is the third leading cause of death by malignancy worldwide. HCC has a poor prognosis due to tumor invasiveness and metastasis. There is substantial evidence that the epithelial-to-mesenchymal transition (EMT) plays a central role in cancer metastasis. In a previous study, a possible association between integrator complex 8 (INTS8) and the progression and development of HCC was discovered. However, its role and the molecular mechanisms in HCC are poorly understood.

Methods

The PROGgeneV2 platform database and Kaplan–Meier plotter analysis were used to analyze the potential effects of INTS8 in HCC. Moreover, we performed migration, transwell, and metastasis assays to investigate the effects of INTS8 on HCC cells. In addition, relevant signaling pathways were examined by western blot and RT-qPCR assays.

Results

We used the PROGgeneV2 platform database and Kaplan–Meier plotter analysis, which indicated that increased expression of INTS8 is associated with poor overall survival of HCC. Moreover, INTS8 expression was higher in HCC tissues than in adjacent noncancerous tissues. INTS8 depletion reduced the invasion and migration of HCC cell lines. Downregulation of INTS8 in vivo resulted in fewer observed metastatic nodules in lungs. Moreover, INTS8 knockdown also increased the expression of epithelial markers (E-cadherin) and decreased the expression of mesenchymal markers (N-cadherin and vimentin) following the downregulation of SMAD4. In addition, pretreatment with TGF-β1 could partly prevent the decrease in the expression of SMAD4 and EMT markers induced by INTS8 knockdown.

Conclusion

Overall, these findings suggest that INTS8 accelerates the EMT in HCC by upregulating the TGF-β signaling pathway.