Melanoma growth stimulatory activity signaling through the class II interleukin-8 receptor enhances the tyrosine phosphorylation of Crk-associated substrate, p130, and a 70-kilodalton protein.
At present several clinical trials both in melanoma and thyroid cancer are using BRAF-inhibitors with encouraging results, which are derived also from numerous <i>in vitro</i> pre-clinical studies aimed at evaluate the possible modulation of immune-cell density and of specific pro-tumorigenic chemokine secretion (CXCL8 and CCL2) by several BRAF-inhibitors in the context of melanoma and thyroid cancer.
Both pretreatment and simultaneous treatment of melanoma cells with IFN-alpha or IFN-beta inhibited the IL-1beta and TNF-alpha up-regulation of IL-8 mRNA levels.
Concomitant decreases in vascular endothelial growth factor, interleukin-8, and matrix metalloproteinase-2 expression levels, as well as decreased blood vessel density (CD31), were found in tumor samples from PAR-1 siRNA-treated mice, suggesting that PAR-1 is a regulator of melanoma cell growth and metastasis by affecting angiogenic and invasive factors.
Enforced expression of IL-8 rendered the melanoma cells highly tumorigenic and increased their metastatic potential as compared with parental and control transfected cells.
From our in vitro and in vivo data we suggest that anoxia-induced regulation of IL-8 might be a characteristic feature of aggressive tumor cells, thus indicating that IL-8 might play a critical role for tumor progression in human malignant melanoma.
Further studies are needed to determine if CXCL8 is predictive of response and to confirm the functions of these chemokine and cytokine in BRAF-mutant melanoma under BRAF inhibition.
In conclusion, these data demonstrate the existence of an autocrine CXCL8/CXCR2 signaling pathway in the bcl-xL-induced melanoma aggressiveness, encouraging the development of novel therapeutic approaches for high bcl-xL-expressing melanoma.
In this prospect article, we summarize our data on the role of AP-2 and CREB/ATF-1 in the progression of human melanoma and report on the development of new fully human antibodies anti-MCAM/MUC18 and anti-IL-8 which could serve as new modalities for the treatment of melanoma.
Mechanistic studies showed that inhibition of (V600E)B-Raf significantly reduced the constitutive secretion of IL-8 from melanoma cells as well as the capacity of endogenous IL-8 production from the melanoma-PMN microenvironment.
Melanoma growth stimulatory activity (MGSA)/growth regulated (GRO) and interleukin-8 (IL-8) are highly related chemokines that have a causal role in melanoma progression.
Metastatic melanoma cell lines secreting high levels of IL-8 and VEGF were more resistant to DTIC than early primary melanomas secreting low levels of the cytokines.
RA, co-administered with the dsRNA mimicker polyinosinic-polycytidylic acid (poly(I:C)), synergizes to mount a specific response program able to sense dsRNA through the concurrent upregulation of TLR3, the dsRNA helicases melanoma differentiation-associated antigen-5 (MDA-5) and RA-inducible gene-1 (RIG-1), and the dsRNA-activated protein kinase (PKR) expression, leading breast cancer cells to specifically express downstream transcriptional targets of dsRNA sensors, such as interferon-β (IFNβ), interleukin-8 (IL-8), chemokine (C-C motif) ligand 5 (CCL5), and C-X-C motif Chemokine 10 (CXCL10).
Taken together, these data confirm that CXCL-8 expression plays a critical role in regulating multiple cellular phenotypes associated with melanoma growth and metastasis.
The melanoma cell lines showed different growth patterns in the brain, and these differences were associated with differences in expression of the angiogenic factors VEGF-A and IL-8 and the matrix metalloproteinases MMP-2 and MMP-9.
The A3 cell line was derived from the human melanoma cell line G-361 by stable transfection with part of the IL-8 promoter (nucleotides -101 to +40 from transcription start) fused to the luciferase coding region.