EFFECT OF PLATELETS IN THE AGGREGATION OF HUMAN MELANOMA CELL LINES

ARBE, MARÍA FLORENCIA; TROTTA, ALDANA; BARRIONUEVO, PAULA; VILLAVERDE M. S.

Congreso; Reunion Anual SAIC2019; 2019

Malignant melanoma is one of the most aggressive cancers and can disseminate from a relatively small primary tumor and metastasize to multiple sites. Hematogenic tumor cell dissemination is one of the main causes of death in patients with malignant melanoma. Although several studies had linked platelets to this process in different malignancies, the exact role of platelets remained controversial. Therefore, the aim of our work was to study the effect of platelets in the aggregation of human melanoma cell lines. First, we evaluated the Platelet Rich Plasma (PRP) cytotoxic effect on tumor cells by the acidic phosphatase assay (APH) on 5-days melanoma and PRP cocultures. We found that viability of melanoma cells was not altered by PRP addition in most cell lines, while others presented increased viability. Next, we focused on the effect of PRP in the aggregation of cells. To elucidate this, PRP was added to non-attached cells of melanoma in 3D culture conditions, at two different times of the spheroid formation. The kinetics of the interaction was followed by optical microscopy up to 7 days. The addition of PRP at the beginning of spheroid formation was responsible of the acceleration and solid compaction of spheroids on all melanoma cell lines tested. However, on already formed spheroids, PRP only helped hM1 and hM10 cell lines, which usually do not form 3D structures, to form spheroids. Finally, we aim to discriminate whether the modulation by PRP was due to platelets presence or soluble mediators. Thus, we co-incubated melanoma cells with PRP, Platelet Poor Plasma (PPP) or washed platelets on 3D culture conditions and followed the cultures as described before. Our results showed that PPP was not able to improve spheroid formation while washed platelets and PRP enhanced the aggregation and compaction of melanoma multiple cell spheroids since the first day of interaction. In summary, our results demonstrate that platelets are able to modulate the aggregation of human melanoma cell lines in vitro.