In vitro evaluation of Axitinib and Sorafenib treatment in glioblastoma cell viability and morphology.

The formation, proliferation, and evolution of glioblastoma (GB) are significantly influenced by pathological angiogenesis. This is supported by several growth factor receptors, such as the vascular endothelial growth factor receptor (VEGFR). In this experiment, we examined how the Food and Drug Administration (FDA) approved VEGFR blockers Sorafenib and Axitinib affect the viability of GB cells in vitro. Cells were cultivated in 96-well culture plates for the experiments, afterwards Sorafenib and Axitinib were administered at doses ranging from 0.3 µM to 80 µM. 2,5-Diphenyl-2H-tetrazolium bromide (MTT) assay was used to assess the impact of VEGFR inhibition on high-grade glioma (HGG) cell lines. To observe the morphological changes in cell shape, we used a 10× magnification microscopy. Our results showed that both Axitinib and Sorafenib retarded GB1B culture proliferation in a dose- and time-dependent manner in comparison to control cohorts that had not received any treatment. The half maximal inhibitory concentration (IC50) value for Axitinib was 3.5839 µM after three days of drug administration and 2.2133 µM after seven days of drug administration. The IC50 value for Sorafenib was 3.5152 µM after three days of drug administration and 1.6846 µM after seven days of drug administration. After the treatment with Axitinib or Sorafenib, very few cells became rounded and detached from the support, others remained adherent to the culture substrate, but acquired a larger, flatter shape. Our results indicate that VEGFR might serve as a key target in the treatment of GB. Although it is known that in vitro some drugs block the VEGFR more potently, clinical evidence is required to show whether this actually translates to better clinical outcomes.

BCL-XL inhibition induces an FGFR4-mediated rescue response in colorectal cancer.

The heterogeneous therapy response observed in colorectal cancer is in part due to cancer stem cells (CSCs) that resist chemotherapeutic insults. The anti-apoptotic protein BCL-XL plays a critical role in protecting CSCs from cell death, where its inhibition with high doses of BH3 mimetics can induce apoptosis. Here, we screen a compound library for synergy with low-dose BCL-XL inhibitor A-1155463 to identify pathways that regulate sensitivity to BCL-XL inhibition and reveal that fibroblast growth factor receptor (FGFR)4 inhibition effectively sensitizes to A-1155463 both in vitro and in vivo. Mechanistically, we identify a rescue response that is activated upon BCL-XL inhibition and leads to rapid FGF2 secretion and subsequent FGFR4-mediated post-translational stabilization of MCL-1. FGFR4 inhibition prevents MCL-1 upregulation and thereby sensitizes CSCs to BCL-XL inhibition. Altogether, our findings suggest a cell transferable induction of a FGF2/FGFR4 rescue response in CRC that is induced upon BCL-XL inhibition and leads to MCL-1 upregulation.

Notoginsenoside R1 activates the Ang2/Tie2 pathway to promote angiogenesis.

BACKGROUND: Therapeutic angiogenesis is a novel strategy for the treatment of ischemic diseases that involves promotion of angiogenesis in ischemic tissues via the use of proangiogenic agents. However, effective proangiogenic drugs that activate the Ang2/Tie2 signaling pathway remain scarce. PURPOSE: We aimed to investigate the proangiogenic activity of notoginsenoside R1 (NR1) isolated from total saponins of Panax notoginseng with regard to activation of the Ang2/Tie2 signaling pathway. METHODS: We examined the proangiogenic effects of NR1 by assessing the effects of NR1 on the proliferation, migration, invasion and tube formation of human umbilical vein endothelial cells (HUVECs). The aortic ring assay and vascular endothelial growth factor receptor inhibitor (VRI)-induced vascular regression in the zebrafish model were used to confirm the proangiogenic effects of NR1 ex vivo and in vivo. Furthermore, the molecular mechanism was investigated by Western blot analysis. RESULTS: We found that NR1 promoted the proliferation, mobility and tube formation of HUVECs in vitro. NR1 also increased the number of sprouting vessels in rat aortic rings and rescued VRI-induced vascular regression in zebrafish. NR1-induced angiogenesis was dependent on Tie2 receptor activation mediated by increased autocrine Ang2 in HUVECs, and inhibition of the Ang2/Tie2 pathway abrogated the proangiogenic effects of NR1. CONCLUSIONS: Our results suggest that NR1 promotes angiogenesis by activating the Ang2/Tie2 signaling pathway. Thus, NR1-induced activation of the Ang2/Tie2 pathway is an effective proangiogenic approach. NR1 may be useful agent for the treatment of ischemic diseases.

Optimizing treatment of renal cell carcinoma with VEGFR-TKIs: a comparison of clinical pharmacology and drug-drug interactions of anti-angiogenic drugs.

Anti-angiogenic treatment is an important option that has changed the therapeutic landscape in various tumors, particularly in patients affected by renal cell carcinoma (RCC). Agents that block signaling pathways governing tumor angiogenesis have raised high expectations among clinicians. Vascular endothelial growth factor receptor-tyrosine kinase inhibitors (VEGFR-TKIs) comprise a heterogeneous class of drugs with distinct pharmacological profiles, including potency, selectivity, pharmacokinetics and drug-drug interactions. Among them, tivozanib is one of the last TKIs introduced in the clinical practice; this drug selectively targets VEGFRs, it is characterized by a favorable pharmacokinetics and safety profile and has been approved as first-line treatment for patients with metastatic RCC (mRCC). In this article, we describe the clinical pharmacology of selected VEGFR-TKIs used for the treatment of mRCC, highlighting the relevant differences; moreover we aim to define the main pharmacologic characteristics of these drug.