Triptolide as a novel agent in pancreatic cancer: the validation using patient derived pancreatic tumor cell line.

BACKGROUND: Triptolide induces apoptosis and DNA damage followed by inhibition of DNA repair associated gene expression. However, there is the limited data for biomarker to predict the benefit to triptolide in various cancers including pancreatic cancer.

METHODS: We investigated the anti tumor efficacy of triptolide in various pancreatic cancer cell lines (Capan-1, Capan-2, SNU-213, SNU-410, HPAFII, and Hs766T) and patient derived cells (PDCs) from metastatic pancreatic cancer patients.

RESULTS: In vitro cell viability assay for triptolide in 6 PC cell lines, the IC50 was 0.01 uM, 0.02 uM, 0.0096 uM for triptolide in Capan-1, Capan-2 and SNU-213. However, the growth of tumor cells was not significantly reduced by triptolide in Hs766T, SNU-410 and HPAFII. The distinct difference of gene expression was also observed between Capan-1, Capan-2 and SNU-213 and Hs766T, SNU-410 and HPAFII. In analysis of pathway using gene expression profiles, the integrin mediated RAS signaling pathway was associated with the sensitivity of the triptolide in PC cell lines. Immunoblot assay showed that Chk2 phosphorylation after triptolide was distinctively observed in SNU-213 sensitive to triptolide but, not in SNU-410 insensitive to triptolide. This finding in immunoblot assay was also reproduced in PDCs originated from pancreatic cancer patients.

CONCLUSIONS: Our findings might be helpful to completely capture the subset of patients who may benefit to tripolide (minnelide). More robust biomarkers such as KRAS mutation and Chk2 phosphorylation and careful clinical trial design using triptolide (minnelide) are warranted.