Cool-associated Tyrosine-phosphorylated Protein 1 Is Required for the Anchorage-independent Growth of Cervical Carcinoma Cells by Binding Paxillin and Promoting AKT Activation

Progerin Inhibits the Proliferation and Migration of Melanoma Cells by Regulating the Expression of Paxillin

Objective

Progerin, the underlying cause of Hutchinson-Gilford Progeria Syndrome (HGPS), has been extensively studied for its impact on normal cells and premature aging patients. However, there is a lack of research on its specific effects on tumor cells. Melanoma is one of the most common malignant tumors with high morbidity and mortality. This study aimed to elucidate the potential therapeutic role of progerin in melanoma.

Materials and Methods

We constructed the melanoma A375 cell line and M14 cell line with stable expression of progerin. The expression of progerin, paxillin, and epithelial-mesenchymal transition (EMT) marker proteins in each cell group was measured using Western blot. The migration, proliferation, and cell cycle of cancer cells were assessed using the transwell assay, wound healing assay, colony formation assay, CCK 8 assay, and flow cytometry. RT-qPCR technology was used to examine the impact of progerin overexpression on microRNA expression. Finally, we transfected paxillin into the progerin overexpression cell group to verify whether progerin regulates the phenotype of tumor cells through paxillin.

Results

Our study demonstrated that overexpression of progerin leads to decreased expression of paxillin and inhibits cancer cell migration, proliferation, EMT process and cell cycle progression. Additionally, rescue experiments revealed that the migration, proliferation ability, and EMT marker protein expression in progerin overexpressing cancer cells could be partially restored by transfecting a plasmid containing the paxillin gene. Mechanistic investigations further revealed that progerin achieves this inhibition of paxillin expression by upregulating miR-212.

Conclusion

This study reveals that progerin may inhibit the migration and proliferation of melanoma cells through the miR-212/paxillin axis, which provides a new approach for the future treatment of this disease.

The Role of Paxillin Aberrant Expression in Cancer and Its Potential as a Target for Cancer Therapy

Paxillin is a multi-domain adaptor protein. As an important member of focal adhesion (FA) and a participant in regulating cell movement, paxillin plays an important role in physiological processes such as nervous system development, embryonic development, and vascular development. However, increasing evidence suggests that paxillin is aberrantly expressed in many cancers. Many scholars have also recognized that the abnormal expression of paxillin is related to the prognosis, metastases, invasion, survival, angiogenesis, and other aspects of malignant tumors, suggesting that paxillin may be a potential cancer therapeutic target. Therefore, the study of how aberrant paxillin expression affects the process of tumorigenesis and metastasis will help to develop more efficacious antitumor drugs. Herein, we review the structure of paxillin and its function and expression in tumors, paying special attention to the multifaceted effects of paxillin on tumors, the mechanism of tumorigenesis and progression, and its potential role in tumor therapy. We also hope to provide a reference for the clinical prognosis and development of new tumor therapeutic targets.

Co-expression of low-risk HPV E6/E7 and EBV LMP-1 leads to precancerous lesions by DNA damage

Background

Low-risk human papillomavirus (HPV), such as types 6 and 11, is considered non-oncogenic, but these types have been detected in oral cancer tissue samples, suggesting their possible involvement in oral carcinogenesis. Because double infection of high-risk HPV and Epstein-Barr virus (EBV) is known to be involved in oral carcinogenesis, we hypothesized that low-risk HPV and EBV co-infection can transform the oral cells. To verify our hypothesis, we evaluated the transformation activity of cell lines expressing both low-risk HPV E6/E7 and EBV LMP-1.

Methods

We transduced HPV6, 11 and 16 E6/E7 genes and EBV LMP-1 gene into primary mouse embryonic fibroblasts. The cell lines were examined for indices of transformation activity such as proliferation, induction of DNA damage, resistance to apoptosis, anchorage-independent growth, and tumor formation in nude mice. To evaluate the signaling pathways involved in transformation, NF-κB and p53 activities were analyzed. We also assessed adhesion signaling molecules associated with anchorage-independent growth such as MMP-2, paxillin and Cat-1.

Results

Co-expression of low-risk HPV6 E6 and EBV LMP-1 showed increased cell proliferation, elevated NF-κB activity and reduced p53 induction. Moreover, co-expression of low-risk HPV6 E6 and EBV LMP-1 induced DNA damage, escaped from apoptosis under genotoxic condition and suppression of DNA damage response (DDR). Co-expression of low-risk HPV11 E6/E7 and EBV LMP-1 demonstrated similar results. However, it led to no malignant characteristics such as anchorage-independent growth, invasiveness and tumor formation in nude mice. Compared with the cells co-expressing high-risk HPV16 E6 and EBV LMP-1 that induce transformation, co-expression of low-risk HPV6 E6 and EBV LMP-1 was associated with low MMP-2, paxillin and Cat-1 expression.

Conclusions

The co-expression of low-risk HPV E6/E7 and EBV LMP-1 does not induce malignant transformation, but it allows accumulation of somatic mutations secondary to increased DNA damage and suppression of DDR. Thus, double infection of low-risk HPV and EBV could lead to precancerous lesions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08397-0.

The Arf-GAP and protein scaffold Cat1/Git1 as a multifaceted regulator of cancer progression

Cool-associated tyrosine phosphorylated protein 1 (Cat1), also referred to as GPCR-kinase interacting protein 1 (Git1), is a ubiquitously expressed, multi-domain protein that is best known for regulating cell shape and migration. Cat1/Git1 functions as a GTPase activating protein (GAP) that inactivates certain members of the ADP-ribosylation factor (Arf) family of small GTPases. It is also a scaffold that brings together several signaling proteins at specific locations within the cell, ensuring their efficient activation. Here we will discuss what is known regarding the classical role of Cat1/Git1 in the regulation of cell morphology and migration, as well as highlight some more recent findings that suggest this interesting signaling/scaffolding protein may also contribute in unexpected ways to oncogenic transformation.