byl719 and dactolisib

Vascular-targeted photodynamic therapy (PDT) selectively disrupts vascular function by inducing oxidative damages to the vasculature, particularly endothelial cells. Although effective tumor eradication and excellent safety profile are well demonstrated in both preclinical and clinical studies, incomplete vascular shutdown and angiogenesis are known to cause tumor recurrence after vascular-targeted PDT. We have explored therapeutic enhancement of vascular-targeted PDT with PI3K signaling pathway inhibitors because the activation of PI3K pathway was involved in promoting endothelial cell survival and proliferation after PDT. Here, three clinically relevant small-molecule inhibitors (BYL719, BKM120, and BEZ235) of the PI3K pathway were evaluated in combination with verteporfin-PDT. Although all three inhibitors were able to synergistically enhance PDT response in endothelial cells, PDT combined with dual PI3K/mTOR inhibitor BEZ235 exhibited the strongest synergism, followed in order by combinations with pan-PI3K inhibitor BKM120 and p110α isoform-selective inhibitor BYL719. Combination treatments of PDT and BEZ235 exhibited a cooperative inhibition of antiapoptotic Bcl-2 family protein Mcl-1 and induced more cell apoptosis than each treatment alone. In addition to increasing treatment lethality, BEZ235 combined with PDT effectively inhibited PI3K pathway activation and consequent endothelial cell proliferation after PDT alone, leading to a sustained growth inhibition. In the PC-3 prostate tumor model, combination treatments improved treatment outcomes by turning a temporary tumor regrowth delay induced by PDT alone to a more long-lasting treatment response. Our study strongly supports the combination of vascular-targeted PDT and PI3K pathway inhibitors, particularly mTOR inhibitors, for therapeutic enhancement.

Topics: Aminopyridines; Animals; Apoptosis; Cell Line, Tumor; Cell Proliferation; Combined Modality Therapy; Endothelial Cells; Humans; Imidazoles; Mice; Morpholines; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasm Recurrence, Local; Neoplasms; Neovascularization, Pathologic; Oxidative Stress; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Photochemotherapy; Porphyrins; Protein Kinase Inhibitors; Quinolines; Signal Transduction; Thiazoles; Verteporfin; Xenograft Model Antitumor Assays

Extensive cross talk exists between PI3K/Akt/mTOR and mitogen-activated protein kinase (MAPK) pathways, and both are upregulated in pancreatic ductal adenocarcinoma (PDAC). Our previous study suggested that epidermal growth factor receptor inhibitor erlotinib which acts upstream of these pathways acts synergistically with PI3K inhibitors in PDAC. Horizontal combined blockade upstream and downstream of these two pathways is therefore explored.. Erlotinib paired with PI3K inhibitor (BYL719) was tested against erlotinib plus dual PI3K/mTOR inhibitor BEZ-235, and MEK inhibitor (PD98059) plus BEZ235, on five primary PDAC cell lines and on two pairs of parent and erlotinib-resistant (ER) cell lines. A range of in vitro assays including cell proliferation, Western blotting, migration, clonogenic, cell cycle, and apopotic assays was used to test for the efficacy of combined blockade.. Dual downstream blockade of the MAPK and PAM pathways was more effective in attenuating downstream molecular signals. Synergy was demonstrated for erlotinib and BEZ235 and for PD-98059 and BEZ-235. This resulted in a trend of increased growth cell cycle arrest, apoptosis, cell proliferation, and colony and migration suppression. This combination showed more efficacy in cell lines with acquired resistance to erlotinib.. The additional mTOR blockade provided by BEZ235 in combined blockade resulted in increased anticancer effect. The hypersensitivity of ER cell lines to additional mTOR blockade suggested PAM pathway oncogenic dependence via mTOR. Dual downstream combined blockade of MAPK and PAM pathways with MEK and PI3K/mTOR inhibitor appeared most effective and represents an attractive therapeutic strategy against pancreatic cancer and its associated drug resistance.

Topics: Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Carcinoma, Pancreatic Ductal; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Movement; Cell Proliferation; Drug Resistance, Neoplasm; Drug Synergism; Erlotinib Hydrochloride; Flavonoids; Humans; Imidazoles; MAP Kinase Signaling System; Mitogen-Activated Protein Kinases; Pancreatic Neoplasms; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Quinolines; Thiazoles; TOR Serine-Threonine Kinases

A prominent role in the pathogenesis of squamous cell carcinoma of the lung (SQCLC) has been attributed to the aberrant activation of the PI3K signaling pathway, due to amplification or mutations of the p110α subunit of class I phosphatidylinositol 3-kinase (PIK3CA) gene. The aim of our study was to determine whether different genetic alterations of PIK3CA affect the biologic properties of SQCLC and to evaluate the response to specific targeting agents in vitro and in vivo. The effects of NVP-BEZ235, NVP-BKM120, and NVP-BYL719 on two-dimensional/three-dimensional (2D/3D) cellular growth, epithelial-to-mesenchymal transition, and invasiveness were evaluated in E545K or H1047R PIK3CA-mutated SQCLC cells and in newly generated clones carrying PIK3CA alterations, as well as in a xenograft model. PIK3CA mutated/amplified cells showed increased growth rate and enhanced migration and invasiveness, associated with an increased activity of RhoA family proteins and the acquisition of a mesenchymal phenotype. PI3K inhibitors reverted this aggressive phenotype by reducing metalloproteinase production, RhoA activity, and the expression of mesenchymal markers, with the specific PI3K inhibitors NVP-BKM120 and NVP-BYL719 being more effective than the dual PI3K/mTOR inhibitor NVP-BEZ235. A xenograft model of SQCLC confirmed that PIK3CA mutation promotes the acquisition of a mesenchymal phenotype in vivo and proved the efficacy of its specific targeting drug NVP-BYL719 in reducing the growth and the expression of mesenchymal markers in xenotransplanted tumors. These data indicate that PIK3CA mutation/amplification may represent a good predictive feature for the clinical application of specific PI3K inhibitors in SQCLC patients.

Topics: Aminopyridines; Animals; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Movement; Cell Proliferation; Class I Phosphatidylinositol 3-Kinases; Disease Models, Animal; Epithelial-Mesenchymal Transition; Humans; Imidazoles; Lung Neoplasms; Morpholines; Mutation; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Quinolines; Signal Transduction; Thiazoles; Xenograft Model Antitumor Assays