Calcium remodeling in colorectal cancer.

ABSTRACT

Colorectal cancer (CRC) is the third most frequent form of cancer and the fourth leading cause of cancer-related death in the world. Basic and clinical data indicate that aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) may prevent colon cancer but mechanisms remain unknown. Aspirin metabolite salicylate and other NSAIDs may inhibit tumor cell growth acting on store-operated Ca2+ entry (SOCE), suggesting an important role for this pathway in CRC. Consistently, SOCE is emerging as a novel player in different forms of cancer, including CRC. SOCE and store-operated currents (SOCs) are dramatically enhanced in CRC while Ca2+ stores are partially empty in CRC cells. These features may contribute to CRC hallmarks including enhanced cell proliferation, migration, invasion and survival. At the molecular level, enhanced SOCE and depleted stores are mediated by overexpression of Orai1, Stromal interaction protein 1 (STIM1) and Transient receptor protein channel 1 (TRPC1) and downregulation of STIM2. In normal colonic cells, SOCE is mediated by Ca2+-release activated Ca2+ channels made of STIM1, STIM2 and Orai1. In CRC cells, SOCE is mediated by different store-operated currents (SOCs) driven by STIM1, Orai1 and TRPC1. Loss of STIM2 contributes to depletion of Ca2+ stores and enhanced resistance to cell death in CRC cells. Thus, SOCE is a novel key player in CRC and inhibition by salicylate and other NSAIDs may contribute to explain chemoprevention activity. SUMMARY: Colorectal cancer (CRC) is the third most frequent form of cancer worldwide. Recent evidence suggests that intracellular Ca2+ remodeling may contribute to cancer hallmarks. In addition, aspirin and other NSAIDs might prevent CRC acting on remodeled Ca2+ entry pathways. In this review, we will briefly describe 1) the players involved in intracellular Ca2+ homeostasis with a particular emphasis on the mechanisms involved in SOCE activation and inactivation, 2) the evidence that aspirin metabolite salicylate and other NSAIDs inhibits tumor cell growth acting on SOCE, 3) evidences on the remodeling of intracellular Ca2+ in cancer with a particular emphasis in SOCE, 4) the remodeling of SOCE and Ca2+ store content in CRC and, finally, 5) the molecular basis of Ca2+ remodeling in CRC. This article is part of a Special Issue entitled ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.