Simultaneous blocking of IL-6 and IL-8 is sufficient to fully inhibit CAF-induced human melanoma cell invasiveness

Abstract

Tumour microenvironment plays a critical role in cell invasion and metastasis. To investigate the role of cancer-associated fibroblasts (CAFs) in melanoma cell invasiveness, we used 3D spheroid invasion assay. The effect of conditioned media from normal fibroblasts and CAFs cultivated alone or co-cultivated with melanoma cells on BLM or A2058 melanoma spheroid invasion was analysed. We found that conditioned media from CAFs and CAFs co-cultured with melanoma cells, especially, promote invasion and migration, without significant effect on melanoma cell proliferation. We further analysed the expression of pro-invasive cytokines IL-8 and IL-6 in media and found that melanoma cells are dominant producers of IL-8 and fibroblasts are dominant producers of IL-6 in 2D monocultures, while co-cultivation of CAFs with melanoma cells induces production/secretion of IL-6 and IL-8 into the media. The analyses of IL-6 levels in 3D cultures and human melanoma samples, however, revealed that at least in some cases IL-6 is also produced directly by melanoma cells. Analysis of the role of IL-6 and IL-8 in CAF-induced melanoma invasion, using neutralising antibodies, revealed that simultaneous blocking of IL-6 and IL-8 is sufficient to fully inhibit CAF-induced human melanoma cell invasiveness. In summary, these experiments indicate the important role of CAFs and IL-8 and IL-6 cytokines in melanoma cell invasiveness.

Ageing as an Important Risk Factor for Cancer

“…Pro-inflammatory cytokines/chemokines such as IL6, IL8 and CXCL1 were also described as having a very important influence on the intercellular crosstalk in other neuroectodermal tumors e.g. in malignant melanoma (63)(64)(65). Moreover, IL6, IL8 and CXCL1 were also found to be part of the gene signature of an aggressive malignant glioblastoma typical of old patients (66).…”

Cancer-associated fibroblasts modulate growth factor signaling and extracellular matrix remodeling to regulate tumor metastasis

“…Interleukin-6 (IL-6) in CAF-conditioned media promoted the invasion of melanoma cells from tumor spheroids into the surrounding type I collagen matrix [30]. Co-culturing CAFs with melanoma cells induced IL-8 secretion by CAFs, and inhibition of IL-6 and IL-8 abrogated the invasion of melanoma spheroids [30].…”

“…Interleukin-6 (IL-6) in CAF-conditioned media promoted the invasion of melanoma cells from tumor spheroids into the surrounding type I collagen matrix [30]. Co-culturing CAFs with melanoma cells induced IL-8 secretion by CAFs, and inhibition of IL-6 and IL-8 abrogated the invasion of melanoma spheroids [30]. Retinoic acid, a lipophilic molecule derived from vitamin A, is thought to exert therapeutic effects by decreasing the secretion of IL-6 by CAFs, thereby limiting pancreatic cancer cell migration and induction of EMT [31,32].…”

Combination therapy for melanoma with BRAF/MEK inhibitor and immune checkpoint inhibitor: a mathematical model

“…IL-10 inhibits the activation of Th1 and CD 8 + T cells [27]. IL-6 and CCL2 recruit MDSCs into tumor [19, 28, 29], and MDSCs produce TGF- β and IL-10. IL-6 and CCL2 also recruit T regulatory T cells (Tregs) [15, 28, 29].…”

“…IL-6 and CCL2 recruit MDSCs into tumor [19, 28, 29], and MDSCs produce TGF- β and IL-10. IL-6 and CCL2 also recruit T regulatory T cells (Tregs) [15, 28, 29]. TGF- β is produced not only by cancer cells and MDSCs, but also by Tregs [30], and Tregs become activated by TGF- β [30, 31].…”