Expression of p33ING1 mRNA and chemosensitivity in brain tumor cells.

Background: Mutations and down-regulation of tumor suppressor genes can contribute to both tumorigenesis and chemotherapy resistance. The tumor suppressor p33ING1 has growth-inhibitory and pro-apoptotic effects recruiting p53 and it plays a role in DNA repair through interaction with PCNA. We questioned whether p33ING1 mRNA expression correlates with the chemosensitivity of brain tumor cells.
Materials and Methods: Various malignant brain tumor cell lines were examined for their sensitivity to cisplatin, doxorubicin, etoposide and the antimitotic agents vincristine and paclitaxel by MTT-cytotoxicity assays. p33ING1 mRNA expression was determined by RT-PCR.
Results: We found that, unlike other tumor types, ING1 levels were higher in glioma cell lines than in normal control cells. Medulloblastoma cells revealed the lowest ING1 expression of the lines tested. Comparing all cell lines, p33ING1 gene expression significantly (p = 0.028) correlated with resistance to vincristine (r2 = 0.87).
Conclusion: Our results suggest that p33ING1 mRNA levels may be used to predict the chemosensitivity of brain tumor cells to vincristine.