Abstract 466: A potential pro-oncogenic role of SERPINB4 in melanoma

Despite recent therapeutic advancements, melanoma remains one of the deadliest forms of skin cancer. Melanoma metastasis and recurrence is associated with the existence of heterogeneous cell populations within tumors that have the ability to both initiate metastatic programs and bypass immune recognition. Tumor cells achieve immune evasion by interfering with immune signaling to limit immune cell infiltration, allowing tumor cell proliferation and growth. SERPINB4 (Squamous Cell Carcinoma Antigen 2 or SCCA2), a serine protease inhibitor, has been shown to regulate the host immune response against tumor cells by inhibiting immune cell activity. Interestingly, certain cancer cell types have been reported to overexpress SERPINB4. However, the expression profile and the functional significance of SERPINB4 in melanoma is not known. In this study, employing ‘The Cancer Genome Atlas’ (TCGA), we found that SERPINB4 is overexpressed and significantly associated with lower overall survival in patients with melanoma. Next, employing a panel of human melanoma cell lines, we demonstrated that SERPINB4 is overexpressed in melanoma cells when compared to normal human melanocytes. In addition, CRISPR knockout of SERPINB4 in high-SERPINB4-expressing A375 melanoma cells resulted in a significant decrease in proliferation of melanoma cells in comparison to control cells. Conversely, forced overexpression of SERPINB4 in low-SERPINB4-expressing SK-MEL-2 and SK-MEL-28 melanoma cells significantly increased melanoma cell proliferation. Moreover, RT-qPCR analyses suggested that SERPINB4 overexpression significantly increased, while its knockout significantly decreased epithelial-mesenchymal transition (EMT) markers (N-cadherin, β-catenin, Snail and Zeb1) in melanoma cells. Additionally, SERPINB4 manipulation significantly modulated the expression of genes involved in antigen-presentation (MHC Class I molecules, HLA-A, -B, and -C) in melanoma cells. Taken together, our data suggested a potential oncogenic role of SERPINB4 in melanoma. Our study also suggested that SERPINB4 might be a promising therapeutic target for melanoma. Indeed, additional in vitro mechanistic and in vivo studies are needed to firmly establish the mechanism and therapeutic potential of SERPINB4 for melanoma management.

Citation Format: Gagan Chhabra, Carl A. Shirley, Rachel K. Robarge, Hassan A. Rizvi, Mary A. Ndiaye, Nihal Ahmad. A potential pro-oncogenic role of SERPINB4 in melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 466.

Production of dextran from sucrose by a newly isolated strain of Leuconostoc mesenteroides (PCSIR-3) with reference to L. mesenteroides NRRL B-512F

A newly isolated strain of Leuconostoc mesenteroides (PCSIR-3) produced a different dextran compared with that of L. mesenteroides NRRL B-512F. Different media compositions used for dextran production showed that media containing CaCl(2) produced dextran in higher quantities compared with other media. The viscosity of the dextran produced in different media varied in nature. Dextran from media 1 and 2 was of higher molecular mass compared with that from media 3, 4 and 5. Dextran production is also effected by the sucrose concentration in the media. The higher the initial concentration of sucrose, the higher is the yield of dextran produced per unit volume; however, the percentage conversion of sucrose into dextran decreases. A continuous drop in pH was associated with growth and dextran production. The yield of dextran increases during the growth phase and maximum yield was obtained at the end of the exponential phase. Dextran produced by L. mesenteroides PCSIR-3 is quite different from the dextran produced by NRRL B-512F. Maximum dextran production from L. mesenteroides PCSIR-3 occurs in 18 h compared with 12 h for NRRL B-512F.