Preventing Calpain Externalization by Reducing ABCA1 Activity with Probenecid Limits Melanoma Angiogenesis and Development

Abstract

Calpains, intracellular proteases specifically inhibited by calpastatin, play a major role in neoangiogenesis involved in tumor invasiveness and metastasis. They are partly exteriorized via the ATP-binding cassette transporter A1(ABCA1) transporter, but the importance of this process in tumor growth is still unknown. The aim of our study was to investigate the role of extracellular calpains in a model of melanoma by blocking their extracellular activity or exteriorization. In the first approach, a B16-F10 model of melanoma was developed in transgenic mice expressing high extracellular levels of calpastatin. In these mice, tumor growth was inhibited by w 3-fold compared with wild-type animals. In vitro cytotoxicity assays and in vivo tumor studies have demonstrated that this protection was associated with a defect in tumor neoangiogenesis. Similarly, in wildtype animals given probenecid to blunt ABCA1 activity, melanoma tumor growth was inhibited by w 3-fold. Again, this response was associated with a defect in neoangiogenesis. In vitro studies confirmed that probenecid limited endothelial cell migration and capillary formation from vascular explants. The observed reduction in fibronectin cleavage under these conditions is potentially involved in the response. Collectively, these studies demonstrate that probenecid, by blunting ABCA1 activity and thereby calpain exteriorization, limits melanoma tumor neoangiogenesis and invasiveness.

Characterization of lipid droplet metabolism patterns identified prognosis and tumor microenvironment infiltration in gastric cancer

“…Past studies have shown that ABCA1 is a lipid transporter protein that plays an important role in maintaining HDL biosynthesis and cellular cholesterol homeostasis ( 64 ). Numerous studies have demonstrated that ABCA1 was associated with the development of a variety of cancers, including colon cancer ( 65 , 66 ), myeloproliferative neoplasms ( 67 ), ovarian cancer ( 68 , 69 ), prostate cancer ( 70 ), and melanoma ( 71 ). ABCA1 may have a dual role in cancer, with ABCA1 showing anti-cancer effects in breast and prostate cancers, but pro-cancer effects in colorectal, bladder and melanoma cancers ( 72 ).…”

Serum level of calpains product as a novel biomarker of acute lung injury following cardiopulmonary bypass

“…Letavernier et al noted that externalization of calpains’ activity increased when endothelial cells were exposed to VEGF-A and norepinephrine ( 37 ). Secretory modalities include cellular vesicles ( 38 ) or, via the ATP-binding cassette transporter A1 (ABCA1) ( 39 ). In the other way of externalization, calpains released from dying cells.…”

Calpain proteolytic systems counteract endothelial cell adaptation to inflammatory environments

“…Furthermore, calpain externalization from human umbilical ECs is reportedly potentiated by physiological stressors, such as VEGF and norepinephrine [39]. More recent, Hanouna et al noted that calpain externalization is prevented by siRNA-based silencing of ABCA1; thus, those processes are probably driven through the molecular machinery [41]. Another possible mechanism underlying calpain externalization is a leakage from deadly cells.…”