Colon cancer cell-derived 12(S)-HETE induces the retraction of cancer-associated fibroblast via MLC2, RHO/ROCK and Ca2+ signalling

Abstract

Retraction of mesenchymal stromal cells supports the invasion of colorectal cancer cells (CRC) into the adjacent compartment. CRC-secreted 12(S)-HETE enhances the retraction of cancer-associated fibroblasts (CAFs) and therefore, 12(S)-HETE may enforce invasivity of CRC. Understanding the mechanisms of metastatic CRC is crucial for successful intervention. Therefore, we studied pro-invasive contributions of stromal cells in physiologically relevant three-dimensional in vitro assays consisting of CRC spheroids, CAFs, extracellular matrix and endothelial cells, as well as in reductionist models. In order to elucidate how CAFs support CRC invasion, tumour spheroid-induced CAF retraction and free intracellular Ca2+ levels were measured and pharmacological- or siRNA-based inhibition of selected signalling cascades was performed. CRC spheroids caused the retraction of CAFs, generating entry gates in the adjacent surrogate stroma. The responsible trigger factor 12(S)-HETE provoked a signal, which was transduced by PLC, IP3, free intracellular Ca2+, Ca2+-calmodulin-kinase-II, RHO/ROCK and MYLK which led to the activation of myosin light chain 2, and subsequent CAF mobility. RHO activity was observed downstream as well as upstream of Ca2+ release. Thus, Ca2+ signalling served as central signal amplifier. Treatment with the FDA-approved drugs carbamazepine, cinnarizine, nifedipine and bepridil HCl, which reportedly interfere with cellular calcium availability, inhibited CAF-retraction. The elucidation of signalling pathways and identification of approved inhibitory drugs warrant development of intervention strategies targeting tumour–stroma interaction.Electronic supplementary materialThe online version of this article (doi:10.1007/s00018-016-2441-5) contains supplementary material, which is available to authorized users.

ORAI channels and cancer

“…However, there has been limited study of other tumour microenvironment players such as cancer associated fibroblasts and adipocytes ( Figure 2). The identification of the important role of Ca 2+ signalling in the interaction with cancer associated fibroblasts and colon cancer cells [77], and adipocytes with ovarian cancer cells at the metastatic niche [78], highlights the need for the field to define the role ORAI Ca 2+ channel in these types of tumour microenvironment interactions.…”

Oxylipins associated with colorectal cancer

“…LOX-derived leukotrienes can promote formation of harmful reactive oxygen species (Savari, Vinnakota, Zhang, & Sjölander, 2014). Hydroxyeicosatetraenoic acids produced by LOX are altered in CRC and can either promote invasiveness of CRC -12S-HETE (Stadler et al, 2017) or exhibit anti-inflammatory properties -15S-HETE (Chen et al, 2003). Many n-3 PUFA oxylipins contribute to resolution of inflammation.…”

The Calcium-Signaling Toolkit in Cancer: Remodeling and Targeting

“…Which Ca 2+ pathway was not identified however, hence this is still an area for further study. Similarly, new work has defined a role for Ca 2+ signaling in CAFs in a colon cancer cell spheroid model (Stadler et al 2017), but again the exact member(s) of the Ca 2+ signaling toolkit involved remains unclear. One member of the Ca 2+ signaling toolkit that is linked to CAFs in prostate cancer is TRPA1.…”