Effects of PI3K inhibitor NVP-BKM120 on acquired resistance to gefitinib of human lung adenocarcinoma H1975 cells

Inhibitory effect of NVP-BKM120 on cholangiocarcinoma cell growth

Abnormal activation of the phosphatidylinositol 3-kinase (PI3K) pathway has been demonstrated in certain types of cancer, including cholangiocarcinoma (CCA). This pathway may therefore be a promising target for CCA treatment. The present study assessed the inhibitory effect of NVP-BKM120, a pan-class I PI3K inhibitor, on CCA cell growth. This inhibitory effect was determined using CCA cell lines and in CCA-inoculated mice. The result from sulforhodamine B (SRB) assay demonstrated that NVP-BKM120 treatment inhibited CCA cell growth in a dose-dependent manner, even at the lowest tested concentration. The in vivo study revealed that oral administration of NVP-BKM120 (10 or 30 mg/kg) to CCA-inoculated nude mice led to a reduction in tumor growth when compared with controls, which was indicated by an immunohistochemical assay for Ki67 expression. In addition, the result from TUNEL assay demonstrated that NVP-BKM120 induced cancer cell death without any signs of toxicity, which indicated by the body weight of mice (data not shown). Western blot analysis demonstrated that NVP-BKM120 inhibited CCA cell growth by suppressing RAC serine/threonine protein kinase/mechanistic target of rapamycin activation and inhibiting the phosphorylation of phosphatase and tensin homolog, which is the inactivation form of the negative regulator of this pathway. Therefore, the results of the present study indicated that NVP-BKM120 should be considered as a therapeutic agent against CCA that could be used to improve treatment.

Hypoxia-inducible factor-1alpha in hepatic fibrosis: A promising therapeutic target

Hypoxia-inducible factor-1alpha (HIF-1α) is a regulated subunit of the hypoxia-inducible factor 1 (HIF1), which functions as a key transcription factor in response to hypoxic stress by regulating genes involved in maintaining oxygen homeostasis. In recent years, a growing body of studies showed that HIF-1α was significantly increased in hepatic fibrotic tissues and activated hepatic stellate cells (HSCs). Furthermore, knockdown of HIF-1α expression inhibited the proliferation and activation of HSCs. In addition, HIF-1α-dependent genes and the extensive network of signaling cascades focus on HIF-1α have been reported to associate with the development of hepatic fibrosis, suggesting that HIF-1α might play a crucial role in hepatic fibrosis. However, the mechanisms by which HIF-1α regulates hepatic fibrosis are still undefined. In this review, we concentrate on multiple signaling pathways and genes related with HIF-1α which may be involved in the development of hepatic fibrosis, further discussing its potential as a novel therapeutic target for hepatic fibrosis.