CHMP4C: A novel regulator of the mitotic spindle checkpoint

Chromatin-modifying protein 4C (CHMP4C) affects breast cancer cell growth and doxorubicin resistance as a potential breast cancer therapeutic target

Breast cancer (BCa) is one of the common malignancies among women. Doxorubicin (Dox), a type of anthracycline anti-tumor drug, is a first-line chemotherapy drug for BCa. It is badly needed to effectively reverse BCa resistance to Dox and improve the clinical symptoms of BCa. Chromatin Modification protein 4C (CHMP4C) is a subunit of the endosomal sorting complex and is expressed in the nucleus and cytoplasm. CHMP4C has been shown to be overexpressed in multiple types of cancers. However, its possible effects on the progression and drug resistance of BCa are still unclear. In this study, we found CHMP4C was highly expressed in BCa tissues and promoted cell proliferation. In addition, CHMP4C promoted resistance of BCa cells to Dox through targeting Snail. We further found that knockdown of CHMP4C inhibited tumor growth and enhanced sensitivity to Dox in vivo. We therefore thought CHMP4C could serve as a target for decreasing BCa drug resistance.

CHMP4C as a novel marker regulates prostate cancer progression through cycle pathways and contributes to immunotherapy

Background

CHMP4C is one of the charged multivesicular protein (CHMP), and is involved in the composition of the endosomal sorting complex required for transport III (ESCRT-III), facilitating the necessary separation of daughter cells. CHMP4C has been proposed to be involved in the progression of different carcinomas. However, the value of CHMP4C in prostate cancer has not yet been explored. Prostate cancer is the most frequently occurring malignancy among male and remains a leading cause of deaths in cancers. So far, clinical therapy of prostate cancer is more inclined to molecular classification and specific clinical treatment and research. Our study investigated the expression and clinical prognosis of CHMP4C and explored its potential regulatory mechanism in prostate cancer. The immune status of CHMP4C in prostate cancer and relative immunotherapy were then analyzed in our study. Based on CHMP4C expression, a new subtype of prostate cancer was established for precision treatment.

Methods

We studied the expression of CHMP4C and relative clinical outcome using the online databases TIMER, GEPIA2, UALCAN, and multiple R packages. Meanwhile, the biological function, immune microenvironment and immunotherapy value of CHMP4C in prostate cancer were further explored on the R software platform with different R packages. Then we performed qRT-PCR, Western Blotting, transwell, CCK8, wound healing assay, colony formation assay and immunohistochemistry to verify the expression of CHMP4C, carcinogenesis and potential regulatory mechanisms in prostate cancer.

Results

We found that the expression of CHMP4C is significant in prostate cancer and the high expression of CHMP4C represents a poor clinical prognosis and malignant progression of prostate cancer. In subsequent vitro validation, CHMP4C promoted the malignant biological behavior of prostate cancer cell lines by adjusting the cell cycle. Based on CHMP4C expression, we established two new subtypes of prostate cancer and found that low CHMP4C expression has a better immune response while high CHMP4C expression was more sensitive to paclitaxel and 5-fluorouracil. Above findings revealed a new diagnostic marker for prostate cancer and facilitated the subsequent precise treatment of prostate cancer.

Identification of pyroptosis-related gene signature for predicting prognosis of patients with pancreatic cancer using bioinformatics

Pancreatic cancer, a common digestive system malignancy, is dubbed the "king of cancers". The role of pyrophosis-related genes (PRGs) in pancreatic cancer prognosis is yet unknown. In pancreatic cancer and normal tissue, we discovered 9 PRGs that are expressed differently in pancreatic cancer and healthy tissue. Based on the differential expression of PRGs, 2 clusters of pancreatic cancer cases could be identified. The 2 groups had significant disparities in total survival time. The prognostic model of a 5-PRGs signature was created using least absolute shrinkage and selection operator (LASSO) method. The median risk score was used to split pancreatic cancer patients in The Cancer Genome Atlas (TCGA) cohort into 2 groups: low risk and high risk. Patients classified as low-risk had significantly higher survival rates than those classified as high-risk (P < .01). The same results were obtained by validating them against the Gene Expression Omnibus database (P = .030). Cox regression statistical analysis showed that risk score was an independent predictor of overall survival in pancreatic cancer patients. Functional enrichment analysis revealed that apoptosis, cell proliferation, and cell cycle-related biological processes and signaling pathways were enriched. Additionally, the immunological status of the high-risk group worsened. In conclusion, a novel pyroptosis-related gene signature can be used to predict pancreatic cancer patient prognosis.

Using Drosophila melanogaster to Analyse the Human Paralogs of the ESCRT-III Core Component Shrub/CHMP4/Snf7 and Its Interactions with Members of the LGD/CC2D1 Family

The evolutionary conserved ESCRT-III complex is a device for membrane remodelling in various cellular processes, such as the formation of intraluminal vesicles (ILVs), cytokinesis, and membrane repair. The common theme of all these processes is the abscission of membrane away from the cytosol. At its heart in Drosophila is Shrub, CHMP4 in humans, which dynamically polymerises into filaments through electrostatic interactions among the protomers. For the full activity, Shrub/CHMP4 requires physical interaction with members of the Lgd protein family. This interaction is mediated by the odd-numbered DM14 domains of Lgd, which bind to the negative interaction surface of Shrub. While only one Lgd and one Shrub exist in the genome of Drosophila, mammals have two Lgd orthologs, LGD1/CC2D1B and LGD2/CC2D1A, as well as three CHMP4s in their genomes, CHMP4A, CHMP4B, and CHMP4C. The rationale for the diversification of the ESCRT components is not understood. We here use Drosophila as a model system to analyse the activity of the human orthologs of Shrub and Lgd at an organismal level. This enabled us to use the plethora of available techniques available for Drosophila. We present evidence that CHMP4B is the true ortholog of Shrub, while CHMP4A and CHMP4C have diverging activities. Nevertheless, CHMP4A and CHMP4C can enhance the activity of CHMP4B, raising the possibility that they can form heteropolymers in vivo. Our structure-function analysis of the LGD1 and LGD2 indicates that the C2 domain of the LGD proteins has a specific function beyond protein stability and subcellular localisation. Moreover, our data specify that CHMP4B interacts more efficiently with LGD1 than with LGD2.

CHMP4C regulates lung squamous carcinogenesis and progression through cell cycle pathway

Background

Lung cancer is a common kind of human malignancies. Lung squamous cell carcinoma (LUSC) is a key subtype of lung cancer. Cell cycle plays an important role in the development and occurrence of LUSC, however, there is still a lack of cell cycle-related genes in LUSC diagnosis and prediction of prognosis.

Methods

We identified differentially expressed genes (DEGs) with "limma" package in R software, and determined the biomarkers of LUSC in diagnosing by performing receiver operating characteristic (ROC) curve analysis, the biomarker effectiveness in diagnosing LUSC was assessed by performing five-fold cross-validation with logistic regression. Kaplan-Meier plot and the nomogram assessed the relationship between the biomarker and patient survival, and WB and qRT-PCR detected the biomarker expression in cells and tissues. Flow cytometry detects the role of the biomarker in the cell cycle.

Results

Integration analysis with The Cancer Genome Atlas (TCGA) database obtained a unique gene related to cell cycle in LUSC (Charged multivesicular body protein 4C, CHMP4C), and the protein of CHMP4C was highly expressed in LUSC tissues. ROC analysis indicated that CHMP4C was a biomarker for the diagnosis of LUSC. Bioinformatic analysis indicated that CHMP4C might be associated with cell cycle in LUSC. CHMP4C knockdown resulted in S-phase arrest of cells with LUSC. According to the survival rate analysis, CHMP4C overexpression indicated poor prognosis in patients with LUSC.

Conclusions

CHMP4C regulates the proliferation process of tumor cells through the cell cycle. It can be used as a potential diagnostic and prognostic biomarker for LUSC.

Chromatin modified protein 4C (CHMP4C) facilitates the malignant development of cervical cancer cells

Despite improvements in prevention and treatment, cervical cancer (CC) still poses a serious threat to women’s health. CHMP4C (chromatin modified protein 4C) is a subunit of the endosomal sorting complex required for transport, which is expressed in both nucleus and cytoplasm. Here, we examined the effect of CHMP4C on the biological behavior of CC cells and the underlying mechanisms. We report that CHMP4C expression is higher in CC tissues, and high CHMP4C expression is associated with lower survival. Up‐regulation of CHMP4C in C‐33A cells accelerates cell proliferation, migration and invasion, whereas down‐regulation of CHMP4C in Ca Ski cells had the opposite effect. Moreover, overexpression of CHMP4C induced activation of the epithelial–mesenchymal transition pathway, whereas depletion of CHMP4C inhibited activation. Our results suggest that CHMP4C contributes to the viability and motility of CC cells by modulating epithelial–mesenchymal transition and may facilitate the identification of novel biomarkers for CC therapy.