buparlisib and Adenocarcinoma

Circulating tumor cells (CTCs) are cells shed from solid tumors into circulation and have been shown to be prognostic in the setting of metastatic disease. These cells are obtained through a routine blood draw and may serve as an easily accessible marker for monitoring treatment effectiveness. Because of the rapid progression of pancreatic ductal adenocarcinoma (PDAC), early insight into treatment effectiveness may allow for necessary and timely changes in treatment regimens. The objective of this study was to evaluate CTC burden as a biomarker of response to treatment with a oral phosphatidylinositol-3-kinase inhibitor, BKM120, in patient-derived xenograft (PDX) mouse models of PDAC. PDX mice were randomized to receive vehicle or BKM120 treatment for 28 days and CTCs were enumerated from whole blood before and after treatment using a microfluidic chip that selected for EpCAM (epithelial cell adhesion molecule) positive cells. This microfluidic device allowed for the release of captured CTCs and enumeration of these cells via their electrical impedance signatures. Median CTC counts significantly decreased in the BKM120 group from pre- to post-treatment (26.61 to 2.21 CTCs/250 µL, p = 0.0207) while no significant change was observed in the vehicle group (23.26 to 11.89 CTCs/250 µL, p = 0.8081). This reduction in CTC burden in the treatment group correlated with tumor growth inhibition indicating CTC burden is a promising biomarker of response to treatment in preclinical models. Mutant enriched sequencing of isolated CTCs confirmed that they harbored KRAS G12V mutations, identical to the matched tumors. In the long-term, PDX mice are a useful preclinical model for furthering our understanding of CTCs. Clinically, mutational analysis of CTCs and serial monitoring of CTC burden may be used as a minimally invasive approach to predict and monitor treatment response to guide therapeutic regimens.

Topics: Adenocarcinoma; Aminopyridines; Animals; Antigens, Neoplasm; Biomarkers; Cell Adhesion Molecules; DNA Mutational Analysis; DNA Primers; Epithelial Cell Adhesion Molecule; Fluorescent Antibody Technique; Humans; Mice; Microfluidic Analytical Techniques; Morpholines; Neoplastic Cells, Circulating; Pancreatic Neoplasms; Statistics, Nonparametric

The effects of class I PI3K inhibitor NVP-BKM120 on cell proliferation, cell cycle distribution, cellular apoptosis, phosphorylation of several proteins of the PI3K/AKT signaling pathway and the mRNA expression levels of HIF1-α, VEGF and MMP9 in the acquired gefitinib resistant cell line H1975 were investigated, and whether NVP-BKM120 can overcome the acquired resistance caused by the EGFR T790M mutation and the underlying mechanism were explored. MTT assay was performed to detect the effect of gefitinib, NVP-BKM120, NVP-BKM120 plus 1 μmol/L gefitinib on growth of H1975 cells. The distribution of cell cycle and apoptosis rate of H1975 cells were examined by using flow cytometry. The mRNA expression levels of tumor-related genes such as HIF1-α, VEGF and MMP9 were detected by using real-time quantitative PCR. Western blotting was used to detect the expression level of phosphorylated proteins in the PI3K/AKT signaling pathway, such as Ser473-p-AKT, Ser235/236-p-S6 and Thr70-p-4E-BP1, as well as total AKT, S6 and 4E-BP1. The results showed that the NVP-BKM120 could inhibit the growth of H1975 cells in a concentration-dependent manner, and H1975 cells were more sensitive to NVP-BKM120 than gefitinib (IC50:1.385 vs. 15.09 μmol/L respectively), whereas combination of NVP-BKM120 and gefitinib (1 μmol/L) did not show more obvious effect than NVP-BKM120 used alone on inhibition of cell growth (P>0.05). NVP-BKM120 (1 μmol/L) increased the proportion of H1975 cells in G0-G1 phase and the effect was concentration-dependent, and 2 μmol/L NVP-BKM120 promoted apoptosis of H1975 cells. There was no significant difference in the proportion of H1975 cells in G0-G1 phase and apoptosis rate between NVP-BKM120-treated alone group and NVP-BKM120 plus genfitinib (1 μmol/L)-treated group or between DMSO-treated control group and gefitinib (1 μmol/L)-treated alone group (P>0.05 for all). It was also found that the mRNA expression levels of these genes were down-regulated by NVP-BKM120 (1 μmol/L), and NVP-BKM120 (1 μmol/L) or NVP-BKM120 (1 μmol/L) plus gefitinib (1 μmol/L) obviously inhibited the activation of Akt, S6 and 4E-BP1 as compared with control group, but single use of gefitinib (1 μmol/L) exerted no significant effect. These data suggested that NVP-BKM120 can overcome gefitinib resistance in H1975 cells, and the combination of NVP-BKM120 and gefitinib did not have additive or synergistic effects. It was also concluded that NVP-BKM120 could overcome the acquired resistance

Topics: Adenocarcinoma; Aminopyridines; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Proliferation; Drug Resistance, Neoplasm; Gefitinib; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Lung Neoplasms; Matrix Metalloproteinase 9; Morpholines; Phosphoinositide-3 Kinase Inhibitors; Quinazolines; RNA, Messenger; Vascular Endothelial Growth Factor A