dactolisib and Head-and-Neck-Neoplasms

Topics: Cell Line, Tumor; Cell Proliferation; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Head and Neck Neoplasms; Humans; Imidazoles; Neoplastic Stem Cells; Phosphatidylinositol 3-Kinase; Phosphorylation; Proto-Oncogene Proteins c-akt; Quinolines; Reactive Oxygen Species; Signal Transduction; Superoxide Dismutase; Up-Regulation

Irreversible electroporation (IRE) kills tumor cells by the delivery of short pulses of strong electric fields. However, the field strength decreases with distance from the treatment center. When IRE cannot eradicate the entire tumor mass, the surviving tumor cells can regrow. NVP-BEZ235 is a dual PI3K/mTOR inhibitor that has been administered orally in clinical trials. However, its hydrophobicity and poor water solubility make NVP-BEZ235 difficult to deliver to target areas. To improve its pharmacokinetics and therapeutic efficacy, we have encapsulated NVP-BEZ235 in a liposome (termed as L-BEZ). Our current study focuses on the long-term antitumor efficacy of IRE and intratumoral injection of L-BEZ in HN5 head and neck cancer xenografts in nude mice. We compared in vitro efficacy, as well as the effect on tumor size and growth rate in vivo, between IRE alone, IRE + oral BEZ, and IRE + L-BEZ over the course of two months. All animals in the control group were sacrificed by day 36, due to excess tumor burden. Tumors treated with IRE alone grew faster and larger than those in the control group. IRE + oral BEZ suppressed tumor growth, but the growth rate increased to that of the controls toward the end of 21 days. Only IRE + L-BEZ eradicated the tumor masses, with no palpable or extractable tumor mass observed after two months. The combination of IRE and L-BEZ could effectively eradicate tumors and prevent recurrence.

Topics: Animals; Antineoplastic Agents; Capsules; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Cell Survival; Electrochemotherapy; Electroporation; Female; Head and Neck Neoplasms; Humans; Hydrophobic and Hydrophilic Interactions; Imidazoles; Liposomes; Mice; Mice, Nude; Quinolines; Solubility; Treatment Outcome; Xenograft Model Antitumor Assays

The PIK3CA mutation is one of the most common mutations in head and neck squamous cell carcinoma (HNSCC). Through this research we attempt to elicit the role of oncogene dependence and effects of targeted therapy on this PIK3CA mutation.. (1) To determine the role of oncogene dependence on PIK3CA-one of the more common and targetable oncogenes in HNSCC, and (2) to evaluate the consequence of this oncogene on the effectiveness of newly developed targeted therapies.. This was a cell culture-based, in vitro study performed at an academic research laboratory assessing the viability of PIK3CA-mutated head and neck cell lines when treated with targeted therapy.. PIK3CA-mutated head and neck cell lines were treated with 17-AAG, GDC-0941, trametinib, and BEZ-235.. Assessment of cell viability of HNSCC cell lines characterized for PIK3CA mutations or SCC25 cells engineered to express the PIK3CA hotspot mutations E545K or H1047R.. Surprisingly, in engineered cell lines, the hotspot E545K and H1047R mutations conferred increased, rather than reduced, IC50 assay measurements when treated with the respective HSP90, PI3K, and MEK inhibitors, 17-AAG, GDC-0941, and trametinib, compared with the SCC25 control cell lines. When treated with BEZ-235, H1047R-expressing cell lines showed increased sensitivity to inhibition compared with control, whereas those expressing E545K showed slightly increased sensitivity of unclear significance.. (1) The PIK3CA mutations within our engineered cell model did not lead to enhanced oncogene-dependent cell death when treated with direct inhibition of the PI3K enzyme yet did show increased sensitivity compared with control with dual PI3K/mTOR inhibition. (2) Oncogene addiction to PIK3CA hotspot mutations, if it occurs, is likely to evolve in vivo in the context of additional molecular changes that remain to be identified. Additional study is required to develop new model systems and approaches to determine the role of targeted therapy in the treatment of PI3K-overactive HNSCC tumors.

Topics: Benzoquinones; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Survival; Class I Phosphatidylinositol 3-Kinases; Head and Neck Neoplasms; Humans; Imidazoles; Indazoles; Inhibitory Concentration 50; Lactams, Macrocyclic; Molecular Targeted Therapy; Mutation; Phosphatidylinositol 3-Kinases; Protein Serine-Threonine Kinases; Pyridones; Pyrimidinones; Quinolines; Squamous Cell Carcinoma of Head and Neck; Sulfonamides; TOR Serine-Threonine Kinases; Tumor Cells, Cultured

Genomic findings underscore the heterogeneity of head and neck squamous cell carcinoma (HNSCC). Identification of mutations that predict therapeutic response would be a major advance. We determined the mutationally altered, targetable mitogenic pathways in a large HNSCC cohort. Analysis of whole-exome sequencing data from 151 tumors revealed the phosphoinositide 3-kinase (PI3K) pathway to be the most frequently mutated oncogenic pathway (30.5%). PI3K pathway-mutated HNSCC tumors harbored a significantly higher rate of mutations in known cancer genes. In a subset of human papillomavirus-positive tumors, PIK3CA or PIK3R1 was the only mutated cancer gene. Strikingly, all tumors with concurrent mutation of multiple PI3K pathway genes were advanced (stage IV), implicating concerted PI3K pathway aberrations in HNSCC progression. Patient-derived tumorgrafts with canonical and noncanonical PIK3CA mutations were sensitive to an mTOR/PI3K inhibitor (BEZ-235), in contrast to PIK3CA-wild-type tumorgrafts. These results suggest that PI3K pathway mutations may serve as predictive biomarkers for treatment selection.

Topics: Biomarkers, Tumor; Carcinoma, Squamous Cell; Cell Line, Tumor; Head and Neck Neoplasms; High-Throughput Nucleotide Sequencing; Humans; Imidazoles; Mutation; Neoplasm Staging; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Quinolines; Squamous Cell Carcinoma of Head and Neck

We investigated the effect of 2-methyl-2-{4-[3-methyl-2-oxo-8-(quinolin-3-yl)-2,3-dihydro-1H-imidazo[4,5-c]quinolin-1-yl]phenyl} propanenitrile (NVP-BEZ235) (Novartis, Basel Switzerland), a dual phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) inhibitor currently being tested in phase I clinical trials, in radiosensitization. NVP-BEZ235 radiosensitized a variety of cancer cell lines, including SQ20B head and neck carcinoma cells and U251 glioblastoma cells. NVP-BEZ235 also increased in vivo radiation response in SQ20B xenografts. Knockdown of Akt1, p110α, or mTOR resulted in radiosensitization, but not to the same degree as with NVP-BEZ235. NVP-BEZ235 interfered with DNA damage repair after radiation as measured by the CometAssay and resolution of phosphorylated H2A histone family member X foci. NVP-BEZ235 abrogated the radiation-induced phosphorylation of both DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and ataxia telangiectasia mutated. Knockdown of either p110α or mTOR failed to decrease the phosphorylation of DNA-PKcs, suggesting that the effect of the drug was direct rather than mediated via p110α or mTOR. The treatment of cells with NVP-BEZ235 also promoted autophagy. To assess the importance of this process in radiosensitization, we used the autophagy inhibitors 3-methyladenine and chloroquine and found that either drug increased cell killing after NVP-BEZ235 treatment and radiation. Knocking down the essential autophagy proteins autophagy related 5 (ATG5) and beclin1 increased NVP-BEZ235-mediated radiosensitization. Furthermore, NVP-BEZ235 radiosensitized autophagy-deficient ATG5(-/-) fibroblasts to a greater extent than ATG5(+/+) cells. We conclude that NVP-BEZ235 radiosensitizes cells and induces autophagy by apparently distinct mechanisms. Inhibiting autophagy via pharmacologic or genetic means increases radiation killing after NVP-BEZ235 treatment; hence, autophagy seems to be cytoprotective in this situation. Our data offer a rationale for combining NVP-BEZ235 along with an autophagy inhibitor (i.e., chloroquine) and radiation in future clinical trials.

Topics: Animals; Autophagy; Carcinoma, Squamous Cell; Cell Line, Tumor; Cellular Senescence; DNA Damage; Down-Regulation; Female; Fibroblasts; Glioblastoma; Head and Neck Neoplasms; Humans; Imidazoles; Mice; Mice, Nude; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Quinolines; Radiation-Sensitizing Agents; Signal Transduction; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays