IL1 alpha, IL6 and MMP13 are required for invasion by the human pituitary cell line HP75
SA Borg1, JA Royds2 & TH Jones1
One third of pituitary adenomas surgically removed are invasive, the presence of which increases the patients' risk of morbidity and mortality. IL6 has been shown to have conflicting effects on growth of human pituitary adenoma cells in culture but may act not only with mitogenic effects but on facilitating tumour invasion into surrounding tissue. We have previously shown IL6 mRNA expression correlates with invasive status and tumour volume(1). IL6 and IL1 are known to stimulate bone resorption.
We have investigated the effect of neutralising IL6 action on human pituitary tumour invasion; we have used the HP75 cell line. We have also studied the effect of blocking IL1 action and of an MMP13 inhibitor, (CL-82198).
Matrigel invasion chamber transwell inserts were rehydrated, cells 0.2x105 were added to each insert with a chemoattractant at the bottom of the well. After 24 hours invading cells were fixed and stained. We have not shown a significant effect of IL6 on growth at 24 hours. Cells on each insert were counted in five fields at 200x magnification with each assay repeated and performed in triplicate.
Cells incubated with IL6 neutralising antibody (300 micrograms/ml) inhibited cell invasion by 51% (basal 51 plus/minus 5 cells/field; IL6Ab 26 plus/minus 3.1 cells/field p<0.0001)[mean plus/minus sem]). Cells were incubated with IL1 neutralising Ab (1 microgram/ml) and with an MMP13 inhibitor (100 micromoles) (basal 51 plus/minus 5 cells/field; IL1 Ab 35 plus/minus 3.6 cells/field p<0.01; MMP13 inhibitor 24 plus/minus 2 cells/field p<0.0001).
We have demonstrated that in vitro invasion by HP75 cells is inhibited by blocking the effects of IL1, IL6 and MMP13. This implies that IL1 alpha, IL6 and MMP13 have important roles in promoting tumour invasion. This data further supports our previous observation that the presence of IL6 correlates with tumour invasive status.
(1)Suliman et al(2001)Endocr Pathol 12 244-5