GLI1 upregulates C-JUN through a specific 130-kDa isoform.

The Hedgehog pathway is molecularly linked to increased resistance to cisplatin and increased repair of platinum-DNA damage, through C-JUN. GLI1, which has five known isoforms, is a positive transcriptional regulator in Hedgehog. Southwestern blot assay, EMSA and ChIP assays indicate that only one of five isoforms of GLI1 may be responsible for the Hedgehog link with C-JUN and thus, increased platinum-DNA adduct repair. Cancer tissues express this 130-kDa isoform at levels 6-fold higher than non-malignant tissues; and this isoform exists in abundance in six of seven ovarian cancer cell lines examined.