mk-2206 and Skin-Neoplasms

Melanoma is a deadly type of skin cancer that is particularly difficult to treat owing to its resistance to radiation therapy. Here, we attempted to determine the key proteins responsible for melanoma radioresistance, with the aim of improving disease response to radiation therapy. Two melanoma cell lines, SK-Mel5 and SK-Mel28, with different radiosensitivities were analysed via RNA-Seq (Quant-Seq) and target proteins with higher abundance in the more radioresistant cell line, SK-Mel28, identified. Among these proteins, integrin αvβ3, a well-known molecule in cell adhesion, was selected for analysis. Treatment of SK-Mel28 cells with cilengitide, an integrin αvβ3 inhibitor, as well as γ-irradiation resulted in more significant cell death than γ-irradiation alone. In addition, Akt, a downstream signal transducer of integrin αvβ3, showed high basic activation in SK-Mel28 and was significantly decreased upon co-treatment with cilengitide and γ-irradiation. MK-2206, an Akt inhibitor, exerted similar effects on the SK-Mel28 cell line following γ-irradiation. Our results collectively demonstrate that the integrin αvβ3-Akt signalling pathway contributes to radioresistance in SK-Mel28 cells, which may be manipulated to improve therapeutic options for melanoma.

Topics: Cell Line, Tumor; Cell Survival; Gamma Rays; Heterocyclic Compounds, 3-Ring; Humans; Integrin alphaVbeta3; Melanoma; Proto-Oncogene Proteins c-akt; Radiation Tolerance; Signal Transduction; Skin Neoplasms; Snake Venoms

Topics: Cell Line, Tumor; Cell Movement; Cell Proliferation; Female; G2 Phase Cell Cycle Checkpoints; Gene Expression Regulation, Neoplastic; Heterocyclic Compounds, 3-Ring; Humans; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Melanoma; Middle Aged; Neovascularization, Pathologic; Proto-Oncogene Proteins c-akt; Rapamycin-Insensitive Companion of mTOR Protein; RNA, Small Interfering; Signal Transduction; Skin Neoplasms; Spheroids, Cellular; Survival Analysis; Uveal Neoplasms

One of major issues in clinical trials in oncology is their high failure rate, despite the fact that the trials were designed based on the data from successful equivalent preclinical studies. This is in part due to the intrinsic homogeneity of preclinical model systems and the contrasting heterogeneity of actual patient responses.. We present a mathematical model-driven framework, phase i (virtual/imaginary) trials, that integrates the heterogeneity of actual patient responses and preclinical studies through a cohort of virtual patients. The framework includes an experimentally calibrated mathematical model, a cohort of heterogeneous virtual patients, an assessment of stratification factors, and treatment optimisation. We show the detailed process through the lens of melanoma combination therapy (chemotherapy and an AKT inhibitor), using both preclinical and clinical data.. The mathematical model predicts melanoma treatment response and resistance to mono and combination therapies and was calibrated and then validated with in vitro experimental data. The validated model and a genetic algorithm were used to generate virtual patients whose tumour volume responses to the combination therapy matched statistically the actual heterogeneous patient responses in the clinical trial. Analyses on simulated cohorts revealed key model parameters such as a tumour volume doubling rate and a therapy-induced phenotypic switch rate that may have clinical correlates. Finally, our approach predicts optimal AKT inhibitor scheduling suggesting more effective but less toxic treatment strategies.. Our proposed computational framework to implement phase i trials in cancer can readily capture observed heterogeneous clinical outcomes and predict patient survival. Importantly, phase i trials can be used to optimise future clinical trial design.

Topics: Algorithms; Antineoplastic Agents; Clinical Trials as Topic; Computer Simulation; Drug Therapy, Combination; Heterocyclic Compounds, 3-Ring; Humans; In Vitro Techniques; Melanoma; Models, Theoretical; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Skin Neoplasms; User-Computer Interface

1α, 25-dihydroxyvitamin D3 (VD3), a secosteriod that has been explored as an anti-cancer agent, was also shown to promote cell survival. Its receptor, the Vitamin D Receptor (VDR), is a direct target of the proto-oncogene ΔNp63α, which is overexpressed in non-melanoma skin cancers. The interconnection between VDR/VD3 signaling and ΔNp63α, led us to examine whether VDR/VD3 signaling promotes keratinocyte proliferation by regulating ΔNp63α levels. Our data demonstrate that VDR regulates ΔNp63α expression at both the transcript and protein level. Interestingly, although low doses of VD3 led to an increase in ΔNp63α protein levels and keratinocyte proliferation, high doses of VD3 failed to increase ΔNp63α protein levels and resulted in reduced proliferation. Increased expression of ΔNp63α by low dose VD3 was shown to be dependent on VDR and critical for the proliferative effects of VD3. VD3-mediated increases in ΔNp63α protein levels occur via activation of both p38 MAPK and Akt kinases. Finally, analysis of samples from patients with squamous cell carcinoma (SCC), basal cell carcinoma and precursors to invasive SCC demonstrated a significant correlation between p63 and VDR levels when compared with healthy normal skin control samples. Delineation of the mechanisms by which VD3 exerts its effect on ΔNp63α and cell proliferation is critical for determining the future of VD3 in cancer therapies.

Topics: Carcinoma, Basal Cell; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cholecalciferol; Heterocyclic Compounds, 3-Ring; Humans; Imidazoles; Keratinocytes; Naphthalenes; p38 Mitogen-Activated Protein Kinases; Proto-Oncogene Mas; Proto-Oncogene Proteins c-akt; Pyrazoles; Pyridines; Receptors, Calcitriol; RNA Interference; RNA, Small Interfering; Signal Transduction; Skin Neoplasms; Transcription Factors; Tumor Suppressor Proteins

Development of small molecular inhibitors against BRAF and MEK has been a breakthrough in the treatment of malignant melanoma. However, the long-term effect is foiled in virtually all patients by the emergence of resistant tumor cell populations. Therefore, mechanisms resulting in the acquired resistance against BRAF and MEK inhibitors have gained much attention and several strategies have been proposed to overcome tumor resistance, including interval treatment or withdrawal of these compounds after disease progression.. Using a panel of cell lines with an acquired resistance against MEK inhibitors, we have evaluated the sensitivity of these cells against compounds targeting AKT/mTOR signaling, as well as novel ERK1/2 inhibitors. Furthermore, the effects of withdrawal of MEK inhibitor on migration in resistant cell lines were analyzed.. We demonstrate that withdrawal of BRAF or MEK inhibitors in tumor cells with an acquired resistance results in reactivation of ERK1/2 signaling and upregulation of EMT-inducing transcription factors, leading to a highly migratory and invasive phenotype of cancer cells. Furthermore, we show that migration in these cells is independent from AKT/mTOR signaling. However, combined targeting of AKT/mTOR using MK-2206 and AZD8055 efficiently inhibits proliferation in all resistant tumor cell lines analyzed.. We propose that combined targeting of MEK/AKT/mTOR or treatment with a novel ERK1/2 inhibitor downstream of BRAF/MEK suppresses proliferation as well as migration and invasion in resistant tumor cells. We provide a rationale against the discontinuation of BRAF or MEK inhibitors in patients with an acquired resistance, and provide a rationale for combined targeting of AKT/mTOR and MEK/ERK1/2, or direct targeting of ERK1/2 as an effective treatment strategy.

Topics: Benzimidazoles; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p27; Drug Resistance, Neoplasm; Extracellular Signal-Regulated MAP Kinases; HCT116 Cells; Heterocyclic Compounds, 3-Ring; HT29 Cells; Humans; Melanoma; Melanoma, Cutaneous Malignant; Mitogen-Activated Protein Kinase Kinases; Morpholines; Neoplasm Invasiveness; Protein Kinase Inhibitors; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins c-akt; Ribosomal Protein S6; Signal Transduction; Skin Neoplasms; TOR Serine-Threonine Kinases

This study investigates the mechanism of action behind the long-term responses (12-16 months) of two BRAF WT melanoma patients to the AKT inhibitor MK-2206 in combination with paclitaxel and carboplatin. Although single agent MK-2206 inhibited phospho-AKT signaling, it did not impact in vitro melanoma growth or survival. The combination of MK-2206 with paclitaxel and carboplatin was cytotoxic in long-term colony formation and 3D spheroid assays, and induced autophagy. Autophagy was initially protective with autophagy inhibitors and deletion of ATG5 found to enhance cytotoxicity. Although prolonged autophagy induction (>6 days) led to caspase-dependent apoptosis, drug resistant clones still emerged. Autophagy inhibition enhanced the cell death response through reactive oxygen species and could be reversed by anti-oxidants. We demonstrate for the first time that AKT inhibition in combination with chemotherapy may have clinical activity in BRAF WT melanoma and show that an autophagy inhibitor may prevent resistance to these drugs.

Topics: Aged; Antineoplastic Combined Chemotherapy Protocols; Autophagy; Carboplatin; Clone Cells; Drug Resistance, Neoplasm; Drug Synergism; Female; Heterocyclic Compounds, 3-Ring; Humans; Male; Melanoma; Molecular Targeted Therapy; Neoplasm Proteins; Paclitaxel; Protein Kinase Inhibitors; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins c-akt; Reactive Oxygen Species; Skin Neoplasms; Spheroids, Cellular; Tumor Stem Cell Assay

Glutamate-triggered signal transduction is thought to contribute widely to cancer pathogenesis. In melanoma, overexpression of the metabotropic glutamate receptor (GRM)-1 occurs frequently and its ectopic expression in melanocytes is sufficient for neoplastic transformation. Clinical evaluation of the GRM1 signaling inhibitor riluzole in patients with advanced melanoma has demonstrated tumor regressions that are associated with a suppression of the mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) pathways. Together, these results prompted us to investigate the downstream consequences of GRM1 signaling and its disruption in more detail. We found that melanoma cells with enhanced GRM1 expression generated larger tumors in vivo marked by more abundant blood vessels. Media conditioned by these cells in vitro contained relatively higher concentrations of interleukin-8 and VEGF due to GRM1-mediated activation of the AKT-mTOR-HIF1 pathway. In clinical specimens from patients receiving riluzole, we confirmed an inhibition of MAPK and PI3K/AKT activation in posttreatment as compared with pretreatment tumor specimens, which exhibited a decreased density of blood vessels. Together, our results demonstrate that GRM1 activation triggers proangiogenic signaling in melanoma, offering a mechanistic rationale to design treatment strategies for the most suitable combinatorial use of GRM1 inhibitors in patients.

Topics: Angiogenesis Inhibitors; Animals; Cell Movement; Heterocyclic Compounds, 3-Ring; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Indazoles; Inhibitor of Apoptosis Proteins; Interleukin-8; Melanoma; Mice; Mice, Nude; Neoplasm Transplantation; Neovascularization, Pathologic; Platelet Endothelial Cell Adhesion Molecule-1; Receptors, Metabotropic Glutamate; Riluzole; Signal Transduction; Sirolimus; Skin Neoplasms; Survivin; Tumor Burden; Vascular Endothelial Growth Factor A