Optimization and Corroboration of the Regulatory Pathway of p42.3 Protein in the Pathogenesis of Gastric Carcinoma

The Function and Regulation of SAPCD2 in Physiological and Oncogenic Processes

The Suppressor APC Domain Containing 2 (SAPCD2) gene, also known by its aliases p42.3 and c9orf140, encodes a protein with an approximate molecular weight of 42.3 kDa. It was initially recognized as a cell cycle-associated protein involved in mitotic progression. Since the initial discovery of this gene, emerging evidence has suggested that its functions extend beyond that of regulating cell cycle progression to include modulation of planar polarization of cell progenitors and determination of cell fate throughout embryonic development. The underlying mechanisms driving such functions have been partially elucidated. However, the detailed mechanisms of action remain to be further characterized. The expression level of SAPCD2 is high throughout embryogenesis but is generally absent in healthy postnatal tissues, with restored expression in adult tissues being associated with various disease states. The pathological consequences of its aberrant expression have been investigated, most notably in the development of several types of cancers. The role of SAPCD2 in tumorigenesis has been supported by in vitro, in vivo, and retrospective clinical investigations and the mechanisms underlying its oncogenic function have been partially revealed. The potential of SAPCD2 as a diagnostic marker and therapeutic target of cancers have also been explored and have shown great promise. However, many questions pertaining to its oncogenic mechanisms as well as its value as a diagnostic marker and therapeutic target remain to be answered. In addition to its function as an oncogene, an involvement of SAPCD2 in other pathological processes such as inflammation has also been implicated and provides additional directions that warrant future investigation. This article reviews the current understanding of the normal cellular functions of SAPCD2 and the relevance of SAPCD2 in disease development with a primary focus on tumorigenesis. The mechanisms that regulate p43.2 expression, including the potential role of microRNAs in regulating its expression, are also reviewed. To the best of our knowledge, we are the first to comprehensively review the published findings regarding the physiological and pathological functions of this gene.

Overexpression of SAPCD2 correlates with proliferation and invasion of colorectal carcinoma cells

Background

Suppressor anaphase-promoting complex domain containing 2 (SAPCD2) is a novel gene playing important roles in the initiation, invasion, and metastasis of several malignancies. However, its role in colorectal carcinoma (CRC) still remains unclear.

Method

In this study, we investigated the expression and biological function of SAPCD2 in CRC. Immunohistochemistry (IHC) for SAPCD2 was performed in 410 pairs of CRC specimens and corresponding normal epithelial tissues, and in 50 adenoma tissues. Clinical pathological factors were analyzed in relation to the expression of SAPCD2. The biological functions of SAPCD2 in CRC cells and its effect on cell cycle were investigated in vitro and in vivo through gain/loss-of-function approaches.

Results

IHC showed that SAPCD2 expression was significantly higher in CRC tissues compared to adenoma and normal epithelium tissues and was correlated with tumor location (p = 0.018). SAPCD2 significantly promoted cell proliferation, migration, and invasion both in vitro and in vivo (p < 0.05). In addition, SAPCD2 knockdown in CRC cells was associated with reduced G₁/S transition, while overexpression caused G₂/M phase arrest (p < 0.05).

Conclusions

In sum, SAPCD2 is overexpressed in CRC tissues and plays a critical role in CRC progression. Therefore, it might represent a promising therapeutic target for CRC treatment.

Establishment of optimal regulatory network of colorectal cancer based on p42.3 protein

Objective: to establish regulatory network of colorectal cancer involving p42.3 protein and to provide theoretical evidence for deep functional exploration of p42.3 protein in the onset and development of colorectal cancer. Methods: with protein similarity algorithm, reference protein set of p42.3 cell apoptosis was built according to structural features of p42.3. GO and KEGG databases were used to establish regulatory network of tumor cell apoptosis involving p42.3; meanwhile, the largest possible working pathway that involves p42.3 protein was screened out based on Bayesian network theory. Besides, GO and KEGG were used to build regulatory network on early diagnosis gene markers for colorectal cancer including WWOX, K-ras, COX-2, p53, APC, DCC and PTEN, at the same time, a regulatory network of colorectal cancer cell apoptosis which involves p42.3 was established. Results: cell apoptotic regulatory network that p42.3 participates in primarily consists of Bcl-2 family genes and the largest possible pathway is p42.3 → FKBP → Bcl-2 centered as FKBP protein. Combined with colorectal cancer regulatory network that involves early diagnosis gene markers, it can be predicted that p42.3 is most likely to regulate the colorectal cancer cell apoptosis through FKBP → Bcl-2 → Bax → caspase-9 → caspase-3 pathway. Conclusion: the colorectal cancer apoptosis network based on p42.3 established in the study provides theoretical evidence for deep exploration of p42.3 regulatory mechanism and molecular targeting treatment of colorectal cancer.

Depletion of p42.3 gene inhibits proliferation and invasion in melanoma cells

PURPOSE

The p42.3 gene is identified recently, and the upregulated expression has been characterized in a variety of human cancers and embryonic tissues but not yet in malignant melanoma. In this study, we explored the role of p42.3 gene in the development of melanoma.

METHODS

The expression of p42.3 was detected by immunohistochemistry staining of 261 cases of patient lesions, including nevi and melanoma, and its correlation with clinical pathological characteristics and prognosis was analyzed. Furthermore, a series of in vitro assays were used to investigate the biological function of p42.3 in melanoma cells.

RESULTS

Immunohistochemistry staining showed an elevated expression level of p42.3 in melanoma compared to nevi (P = 0.001). Statistical analysis indicated that this high level was well correlated with patients' clinical stage (P = 0.045), but not with gender, age, clinical type, mitotic rate, and overall survival (P > 0.05). Moreover, in vitro assays showed knockdown p42.3 gene expression could inhibit the biological profiling, including proliferation, migration, and invasion of melanoma cells, and also affect PI3K/Akt pathway, MAPK pathway, and β-catenin.

CONCLUSIONS

This study suggests that p42.3, acting like an oncogene, is involved in the malignant transformation process of melanoma and may serve as a biomarker for diagnostic and treatment purposes.