RESUMEN
Objective CD44, a cell surface glycoprotein, plays an important role in tumor growth and glycolysis.The aim of this study was to investigate the effects of neutralizing CD44 antibodies on the growth and glycolytic metabolism of B16 cells in melanoma in vitro.Methods B16 cells were treated with control antibodies (50 μg/mL) or different concentrations of CD44 antibodies (2, 10, and 50 μg/mL) for 24 hours, followed by examination of the activation of the AKT pathway in the B16 cells by Western blot.Then the tumor cells were also treated with control antibodies (50 μg/mL) or CD44 antibodies (50μg/mL) after pretreated with API-2 (4 μmol/L) in a parallel test.After 48 hours of treatment, the expression of lactate dehydrogenase A (LDHA) in the B16 cells and the level of lactate in the culture supernatant were detected by immunofluorescence and colorimetry, respectively.Lastly, the B16 cells were treated with control antibodies (50μg/mL), API-2 (4 μmol/L), CD44 antibodies (50μg/mL), or API-2 + CD44 antibodies for 96 hours, followed by measurement of the proliferation of the cells by MTT and their apoptosis by AO/EB and AnnexinV staining.Results In comparison with the control antibody group, the level of AKT phosphorylation (p-AKT) in the B16 cells showed a concentration-dependent increase in the 2, 10, and 50 μg/mL CD44 antibody groups (1.00±0.25 vs 2.51±0.32, 3.89±0.46, and 4.07±0.42, P<0.01), and the expression of LDHA was increased by (2.13±0.24) times, with the lactate level in the culture supernatant significantly elevated from (35.32±3.24) to (56.34±8.19) mmol/L (P<0.01) after 96 hours of treatment with 50 μg/mL CD44 antibodies.Treatment with API-2+CD44 antibodies, however, suppressed the increase in the LDHA expression and reduced the level of lactate.Compared with the control antibody group, the proliferation rate of the B16 cells was markedly decreased in the API-2, CD44 antibody, and API-2+CD44 antibody groups ([103±12.91] vs [84.87±19.35], [71.35±16.23], and [41.16±9.15]%, P<0.05), while the apoptosis rate remarkably increased ([5.23±0.96] vs [13.65±4.27], [19.21±3.53], and [43.21±7.87]%, P<0.01).Conclusion Neutralizing the function of CD44 in the B16 cells in vitro can inhibit the growth of the cells and promote AKT-mediated glycolytic metabolism, while suppressing the AKT pathway may enhance the antitumor activity of the CD44 antibody.