The kin17 Protein in Murine Melanoma Cells

Identification and quantification of serum KIN17 protein based on ELISA assay and exploring its clinical diagnostic value in liver cancer

It has been well-elaborated that KIN17 protein is closely related to the expression, development and prognosis of liver cancer; however, till date, there has been no study about detecting the KIN17 protein in serum, which is important to developing clinical applications. The objective of this work is to detect serum KIN17 protein by the ELISA method and to explore the diagnostic significance of the KIN17 protein in liver cancer. First, we verified the ELISA method for serum KIN17 measurement according to five aspects: accuracy, precision, specificity, stability and detection limit. Results illustrate that the recovery rate of the ELISA method can be controlled between 90% and 110%, the variation coefficient of intra-assay can be controlled within 16%, and the variation coefficient of inter-assay can be controlled within 10%. There is no non-specific reaction with common tumor markers, and the detection limit can reach 0.125 ng mL-1. The results show that the KIN17 protein can be detected by ELISA, and there is a significant rise in KIN17 concentration in a liver cancer group compared with a healthy group, whose average concentrations are 1.730 ng mL-1 and 0.3897 ng mL-1, respectively. On this basis, we hypothesize that the serum KIN17 protein can serve as a potential biomarker of liver cancer and be measurable with the verified ELISA system after specific ultrafiltration and centrifugation, which is of great significance for the diagnosis and treatment of liver cancer.

Roles and regulatory mechanisms of KIN17 in cancers (Review)

KIN17, which is known as a DNA and RNA binding protein, is highly expressed in numerous types of human cancers and was discovered to participate in several vital cell behaviors, including DNA replication, damage repair, regulation of cell cycle and RNA processing. Furthermore, KIN17 is associated with cancer cell proliferation, migration, invasion and cell cycle regulation by regulating pathways including the p38 MAPK, NF-κB-Snail and TGF-β/Smad2 signaling pathways. In addition, knockdown of KIN17 was found to enhance the sensitivity of tumor cells to chemotherapeutic agents. Immunohistochemical analysis revealed that there were significant differences in the expression of KIN17 between cancer tissues and adjacent tissues. Both the Kaplan-Meier survival analysis and multivariate Cox regression analysis indicated that KIN17 is aberrantly high expressed in various tumor tissues and is also associated with poor prognosis in patients with various tumor types. Taken together, KIN17 has key roles in tumorigenesis and cancer development. Investigating the relationship between KIN17 and neoplasms will provide a vital theoretical basis for KIN17 to serve as a diagnostic and prognostic biomarker for cancer patients and as a potential target for cancer therapy.

Deficiency of kin17 Facilitates Apoptosis of Cervical Cancer Cells by Modulating Caspase 3, PARP, and Bcl-2 Family Proteins

Background

The treatment of cervical cancer in the late stage is still quite challenging, because of nonspecificity in conventional therapies and the lack of molecular targeted drugs. It is necessary to find novel biomarkers for cervical cancer treatment.

Methods

In the present study, cervical cell lines HeLa and SiHa with kin17 knockdown were constructed by transfection of the recombinant lentiviral vector carrying KIN17 siRNA and screened by puromycin. The established cells with kin17 knockdown were determined by fluorescence observation and western blotting. Cell apoptosis and the mitochondrial membrane potential (MMP) were detected by flow cytometry. The activity of caspase 3 enzyme was tested by spectrophotometry. The expression profile of apoptosis-associated proteins was analyzed by western blotting. Finally, we used bioinformatics and proteomic data to analyze KIN-related genes in cervical cancer.

Results

The results showed high fluorescent positive rates (>90%) and high gene silencing efficiency (>65%) in HeLa and SiHa cells transfected with gene silencing vectors. Moreover, kin17 deficiency decreased the MMP and increased the apoptosis rates in HeLa and SiHa cells, respectively. Furthermore, knockdown of kin17 enhanced the activity of caspase 3 enzyme, increased the expression of cleaved PARP and Bim, while decreasing the expression of Bcl-xL and phosphorylated BAD in HeLa and SiHa cells. Identification of KIN-related prognostic genes in cervical cancer revealed that a total of 5 genes (FZR1, IMPDH1, GPKOW, XPA, and DDX39A) were constructed for this risk score, and the results showed that CTLA4 expressions were negatively correlated with the risk score.

Conclusion

Our findings demonstrated that kin17 knockdown facilitates apoptosis of cervical cancer cells by targeting caspase 3, PARP, and Bcl-2 family proteins. Besides, kin17 could regulate cancer cell apoptosis through the mitochondrial pathway and could be used as a novel therapeutic target for the regulation of cell apoptosis in cervical cancer.

Interactome Analysis of KIN (Kin17) Shows New Functions of This Protein

KIN (Kin17) protein is overexpressed in a number of cancerous cell lines, and is therefore considered a possible cancer biomarker. It is a well-conserved protein across eukaryotes and is ubiquitously expressed in all cell types studied, suggesting an important role in the maintenance of basic cellular function which is yet to be well determined. Early studies on KIN suggested that this nuclear protein plays a role in cellular mechanisms such as DNA replication and/or repair; however, its association with chromatin depends on its methylation state. In order to provide a better understanding of the cellular role of this protein, we investigated its interactome by proximity-dependent biotin identification coupled to mass spectrometry (BioID-MS), used for identification of protein-protein interactions. Our analyses detected interaction with a novel set of proteins and reinforced previous observations linking KIN to factors involved in RNA processing, notably pre-mRNA splicing and ribosome biogenesis. However, little evidence supports that this protein is directly coupled to DNA replication and/or repair processes, as previously suggested. Furthermore, a novel interaction was observed with PRMT7 (protein arginine methyltransferase 7) and we demonstrated that KIN is modified by this enzyme. This interactome analysis indicates that KIN is associated with several cell metabolism functions, and shows for the first time an association with ribosome biogenesis, suggesting that KIN is likely a moonlight protein.

KIN17 promotes tumor metastasis by activating EMT signaling in luminal-A breast cancer

Background

Breast cancer (BC), the most common cause of cancer death in women, overtook lung cancer as the leading cause of cancer worldwide in 2020. Although many studies have proposed KIN17 as a biomarker of tumorigenesis in different cancer types, its role in tumor metastasis, particularly in BC metastasis, has been underexplored. This study aimed to explore the role of KIN17 in BC metastasis.

Methods

Survival analyses was performed to identify the association between KIN17 expression and BC patient survival in silico. Using lentivirus constructs, we developed bidirectional KIN17 expression (KD, knockdown; OE, overexpression) cellular models of luminal‐A (Lum‐A) breast cancer MCF‐7 cells. We performed in vitro wound healing, transwell with and without Matrigel assays, and in vivo tail‐vein metastasis assay to evaluate the migration and invasion abilities of MCF‐7 with stable KIN17 knockdown or overexpression. Western blotting was performed to compare the changes in protein expression.

Results

We found that KIN17 expression was associated with poor overall survival (OS), relapse‐free survival (RFS), distant metastasis‐free survival (DMFS) and post‐progression survival (PPS), particularly in Lum‐A breast cancer patients. Later, we found that KIN17 knockdown inhibited migration and invasion of MCF‐7 cells via regulating EMT‐associated signaling pathways in vitro and decreases metastatic spread of the disease in vivo. In contrast, KIN17 overexpression promoted migration and invasion of MCF‐7 cells in vitro and increased the metastatic spread of the disease in vivo.

Conclusions

Overall, our findings provide preliminary data which suggests KIN17 of importance to target in metastatic Lum‐A patients.

Elevated Expression of Kin17 in Cervical Cancer and Its Association With Cancer Cell Proliferation and Invasion

BACKGROUND

Cervical cancer is one of the most common cancers in women worldwide. Emerging evidence suggests that kin17 is a tumor-promoting protein in some types of solid tumors. However, whether kin17 contributes to cervical cancer carcinogenesis remains unknown.

METHODS

Kin17 expression in clinical samples from Guangdong Women and Children's Hospital and Health Institute was detected by immunohistochemical staining. A series of functional experiments including 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, 5-bromo-2'-deoxyuridine assay, colony formation, transwell assay, flow cytometry of apoptosis, and cell cycle were performed to explore the roles of kin17 in cervical cancer cells HeLa.

RESULTS

In this study, we showed for the first time that the expression of kin17 was significantly increased in clinical cervical cancer samples, and associated with tumor differentiation, lymph node metastasis, and ki-67 expression in a clinicopathologic characteristics review. Furthermore, silence of kin17 in HeLa cells inhibited cell proliferation, clone formation, cell cycle progression, migration, and invasion, and also promoted cell apoptosis.

CONCLUSION

Our findings demonstrate that kin17 is closely related to the cell proliferation and invasion of cervical cancer and could be a novel diagnostic and therapeutic target for cervical cancer management. The underlying mechanisms should be elucidated in future research.