Metformin is an oral antidiabetic drug of the biguanide class. Several epidemiological and case-control studies reported that diabetics using metformin may have lower cancer risk in comparison to those using other antidiabetic medications. Recent studies in experimental models suggest that another biguanide, phenformin, has higher anticancer activity compared with metformin. The aim of this study was to evaluate the effects of metformin and phenformin in Non-Small Cell Lung Cancer (NSCLC) models. In particular, the effects of these compounds in LKB1 or LKB1/KRAS mutated compared to wild type models have been investigated. NSCLC cell lines (A549, H460, H1299, LT73) have been treated with either metformin or phenformin to evaluate in vitro dose/response depending on the different mutational status of KRAS and LKB1 genes. The effects of the two biguanide have been investigated also in vivo models, exploiting the panel of Patient Derived Xenografts (PDXs) directly generated from NSCLC patients in our Institute. In vitro experiments indicated that cell lines with already impaired metabolism (LKB1 and/or KRAS mutated) were more sensitive to phenformin treatment. Interestingly, treatments of these cell lines with r phenformin resulted in a 50% decrease in the amount of CD133+ Tumor Initiating Cells (TIC). Moreover, high doses of phenformin (LD75) did not result in the increase of TIC previously observed after Cisplatin treatment. In vivo, early treatments (Tumor Volume = 50-100mm3) of an LKB1 mutated PDX model resulted in a significant reduction of tumor volume (300 ± 50 mm3 in phenformin treated vs 750 ± 100 mm3 in vehicle treated tumors) already after three weeks of treatment (100mg/Kg/day). Importantly, no regrowth was observed in responding tumors even after the end of treatments. No effects were observed in LKB1 wild type PDX treated with phenformin. Taken together, these preliminary data indicate a selective action of phenformin on LKB1 mutated lung adenocarcinoma models in vitro and in vivo. Interestingly, this compound seems to be more active in TIC than normal chemotherapeutic drugs (i.e. cisplatin). Effects of biguanide on TIC could be the cause of the lack of tumor regrowth after treatment, thus making these compounds potentially useful in counteracting disease recurrence and/or metastasis formation. Further investigations are needed to elucidate the different effects of metformin and phenformin in double mutated (LKB1 and KRAS) PDXs models.
Citation Format: Massimo Moro, Luca Roz, Roberto Caserini, Ugo Pastorino, Gabriella Sozzi. Effects of phenformin in LKB1/KRAS mutated non-small cell lung cancer patient derived xenograft. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1216. doi:10.1158/1538-7445.AM2014-1216