Hyaluronan modulates intracellular signaling: cell migration, metallopreteinases and apoptosis in tumor cell lines

ALANIZ LAURA; GARCÍA MARIANA; RUSSO ROSALÍA; RODRIGUEZ-GALLO CAROLA; ALVAREZ ELIDA; HAJOS SILVIA E

Córdoba, Argentina

Congreso; VII Congreso Latinoamericano de Inmunología - Asociación Latinoamericana de Inmunología (ALAI) - Sociedad Argentina de Inmunología (SAI); 2005

ALAI and SAI

Abstract In this work we described cellular and molecular challenged as a consequence of CD44-hyaluronan (HA) interaction. We also studied whether high and low molecular weight (MW) HA or their  oligosaccharides (oHA) act differentially on the  activation of intracellular signalling. LBLa and LBLc murine lymphoma cell lines were used for this purpose. The migratory capacity toward HA, evaluated in vitro in quimiotaxis chamber, showed that mostly the more aggressive LBLa cell line migrated, besides differences were found in the migration index depending of MW of the HA used. MMP-9 was evaluated by zymography demonstrating that only LBLa cell line express this activity, which was modulated by both high and low MW HA. RT-PCR confirmed that improved MMP-9 activity was related with  an increase of mRNA expression. MMP-14 was evaluated by Western Blot and RT-PCR showing that both cell lines expressed this enzyme, which was modulated by HA. Cell survival was analyzed after treatment with HA or oHA using ANEXIN V. The results indicated that only oHA induced 20% apoptosis in the cell lines, while  native HA failed to do it. Intracellular signaling pathways involved in these effects showed that HA increase PI3K/AKT phosphorylation in both cell lines, indicating activation of both proteins, on the other hand while oHA diminished the effect similarly to the specific inhibitor of PI3K wortmannin. HA treatment also induced TIAM traslocation to the cellular membrane, indicating activation of this protein. NFkB constitutive activity was higher for LBLa; after treatment HA but not oHA increased the effect. In LBLa the expression of MMP-9 is linked with NFkB activation since its inhibition by the specific inhibitor BAY 10-7082 was able to block the  activity induced by HA. Apoptosis induction by oHA in both cell lines would be dependent on PI3K/AKT activity but independent of NFkB activity, since apoptosis levels reached after treatment with oHA were similar, although constitutive activity of NFkB in both cell lines was  different. To conclude, the results showed in this work could explain the different metastatic capacity of the cell lines observed in vivo.