pd-0325901 and Lung-Neoplasms

The Ras-Raf-MAPK pathway has been implicated in lung carcinogenesis and, potentially, the maintenance of the malignant phenotype in these tumors. Mutations in ras and B-raf genes have been described in lung cancer, representing one of the few examples of tandem mutations in a signaling cascade. As a result, numerous approaches to inhibiting this pathway in lung cancer have been explored in the past decade. The most promising approach to date appears to be the inhibition of mitogen-activated ERK kinase or MEK. In this review, the potential utility of MEK inhibitors in the therapy of lung cancer is discussed.

Topics: Benzamides; Carcinoma, Non-Small-Cell Lung; Diphenylamine; Enzyme Inhibitors; Extracellular Signal-Regulated MAP Kinases; Genes, ras; Humans; Lung Neoplasms; MAP Kinase Signaling System; Mutation; raf Kinases; ras Proteins; Signal Transduction

Mutations in KRAS result in a constitutively activated MAPK pathway. In KRAS-mutant tumours existing treatment options, e.g. MEK inhibition, have limited efficacy due to resistance through feedback activation of epidermal growth factor receptors (HER).. In this Phase 1 study, the pan-HER inhibitor dacomitinib was combined with the MEK1/2 inhibitor PD-0325901 in patients with KRAS-mutant colorectal, pancreatic and non-small-cell lung cancer (NSCLC). Patients received escalating oral doses of once daily dacomitinib and twice daily PD-0325901 to determine the recommended Phase 2 dose (RP2D). (Clinicaltrials.gov: NCT02039336).. Eight out of 41 evaluable patients (27 colorectal cancer, 11 NSCLC and 3 pancreatic cancer) among 8 dose levels experienced dose-limiting toxicities. The RP2D with continuous dacomitinib dosing was 15 mg of dacomitinib plus 6 mg of PD-0325901 (21 days on/7 days off), but major toxicity, including rash (85%), diarrhoea (88%) and nausea (63%), precluded long-term treatment. Therefore, other intermittent schedules were explored, which only slightly improved toxicity. Tumour regression was seen in eight patients with the longest treatment duration (median 102 days) in NSCLC.. Although preliminary signs of antitumour activity in NSCLC were seen, we do not recommend further exploration of this combination in KRAS-mutant patients due to its negative safety profile.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Benzamides; Carcinoma, Non-Small-Cell Lung; Colorectal Neoplasms; Diphenylamine; ErbB Receptors; Female; Humans; Lung Neoplasms; Male; Middle Aged; Mitogen-Activated Protein Kinase Kinases; Mutation; Neoplasms; Pancreatic Neoplasms; Proto-Oncogene Proteins p21(ras); Quinazolinones

To evaluate the efficacy of mitogen-activated protein kinase/extracellular signal-related kinase kinase inhibitor PD-0325901 in advanced non-small cell lung cancer patients who had experienced treatment failure after, or were refractory to, standard systemic therapy.. This open-label, phase II study initially evaluated 15 mg PD-0325901 twice daily administered intermittently (3 weeks on/1 week off; schedule A). As this schedule was not well tolerated, a second schedule was introduced as follows: 5 days on/2 days off for 3 weeks, followed by 1 week off (schedule B). The primary end point was objective response.. All patients had received prior systemic therapy (median of two regimens, including epidermal growth factor receptor inhibitors in 26%). Of 13 patients treated on schedule A, three discontinued due to adverse events (blurred vision, fatigue, and hallucinations, respectively). Twenty-one patients received schedule B. Main toxicities included diarrhea, fatigue, rash, vomiting, nausea, and reversible visual disturbances. Hematologic toxicity consisted mainly of mild-to-moderate anemia, without neutropenia. Chemistry abnormalities were rare. Mean (coefficient of variation) PD-0325901 trough plasma concentrations were 100 ng/mL (52%) and 173 ng/mL (73%) for schedules A and B, respectively, above the minimum target concentration established in preclinical studies (16.5 ng/mL). There were no objective responses. Seven patients had stable disease. Median (95% confidence interval) progression-free survival was 1.8 months (1.5-1.9) and overall survival was 7.8 months (4.5-13.9).. PD-0325901 did not meet its primary efficacy end point. Future studies should focus on PD-0325901 schedule, rational combination strategies, and enrichment of patient selection based on mode of action.

Topics: Adenocarcinoma; Administration, Oral; Adult; Aged; Aged, 80 and over; Benzamides; Carcinoma, Large Cell; Carcinoma, Non-Small-Cell Lung; Carcinoma, Squamous Cell; Diphenylamine; Female; Humans; Lung Neoplasms; Male; Middle Aged; Mitogen-Activated Protein Kinase Kinases; Survival Rate; Tissue Distribution; Treatment Outcome

BH3 mimetic drugs, which inhibit prosurvival BCL2 family proteins, have limited single-agent activity in solid tumor models. The potential of BH3 mimetics for these cancers may depend on their ability to potentiate the apoptotic response to chemotherapy and targeted therapies. Using a novel class of potent and selective MCL1 inhibitors, we demonstrate that concurrent MEK + MCL1 inhibition induces apoptosis and tumor regression in

Topics: A549 Cells; Aniline Compounds; Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Benzamides; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Diphenylamine; Humans; Lung Neoplasms; Mice, Knockout; Mice, Nude; Mice, SCID; Mitogen-Activated Protein Kinase Kinases; Myeloid Cell Leukemia Sequence 1 Protein; Protein Kinase Inhibitors; Proto-Oncogene Proteins p21(ras); Sulfonamides; Tumor Burden; Xenograft Model Antitumor Assays

Kinase inhibitors are important cancer therapeutics. Polypharmacology is commonly observed, requiring thorough target deconvolution to understand drug mechanism of action. Using chemical proteomics, we analyzed the target spectrum of 243 clinically evaluated kinase drugs. The data revealed previously unknown targets for established drugs, offered a perspective on the "druggable" kinome, highlighted (non)kinase off-targets, and suggested potential therapeutic applications. Integration of phosphoproteomic data refined drug-affected pathways, identified response markers, and strengthened rationale for combination treatments. We exemplify translational value by discovering SIK2 (salt-inducible kinase 2) inhibitors that modulate cytokine production in primary cells, by identifying drugs against the lung cancer survival marker MELK (maternal embryonic leucine zipper kinase), and by repurposing cabozantinib to treat FLT3-ITD-positive acute myeloid leukemia. This resource, available via the ProteomicsDB database, should facilitate basic, clinical, and drug discovery research and aid clinical decision-making.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Cytokines; Drug Discovery; fms-Like Tyrosine Kinase 3; Humans; Leukemia, Myeloid, Acute; Lung Neoplasms; Mice; Molecular Targeted Therapy; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Proteomics; Xenograft Model Antitumor Assays

Mesenchymal-type cancers after epithelial mesenchymal transition (EMT) were recently shown to acquire chemoresistance through expressing EMT specific transcription factors. However, druggable (or actionable) target(s) for chemoresistance in mesenchymal-type lung cancers remain unidentified. Here, we used a public clinical genomic database and mesenchymal lung cancer cells (MLCC) model derived from the A549 lung adenocarcinoma cell line to demonstrate that BCL2 expression, which is highly induced in mesenchymal-type lung cancers, as a predictor of poor prognosis in mesenchymal lung cancer patients and association with acquired chemoradioresistance. Thereby, combination treatment with BH3 mimetics, such as ABT-263 and ABT-737, clearly attenuated chemoresistance in MLCCs. BCL2 expression in MLCCs was induced by ERK1 activity through the upregulation of the MEK1/ERK1 scaffold protein MEK partner-1 (MP1). Interfering with the MEK1/MP1/ERK1 axis using a MEK1 inhibitor or MP1 depletion repressed BCL2 expression and sensitized MLCCs to chemoradiotherapy. Taken together, our results suggest that targeting druggable proteins in the MEK1/MP1/ERK1/BCL2 axis, such as MEK1 or BCL2, with currently available FDA approved drugs is a currently feasible approach to improve clinical outcomes of mesenchymal lung cancer patients.

Topics: A549 Cells; Adaptor Proteins, Signal Transducing; Adenocarcinoma; Adenocarcinoma of Lung; Aniline Compounds; Antineoplastic Combined Chemotherapy Protocols; Benzamides; Biphenyl Compounds; Cell Proliferation; Cell Survival; Chemoradiotherapy; Diphenylamine; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Etoposide; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; MAP Kinase Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; Molecular Mimicry; Nitrophenols; Peptide Fragments; Piperazines; Protein Kinase Inhibitors; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Radiation Tolerance; RNA Interference; Signal Transduction; Sulfonamides; Transfection; Up-Regulation

The histone methyltransferase NSD2/WHSC1/MMSET is overexpressed in a number of solid tumors but its contribution to the biology of these tumors is not well understood. Here, we describe that NSD2 contributes to the proliferation of a subset of lung cancer cell lines by supporting oncogenic RAS transcriptional responses. NSD2 knock down combined with MEK or BRD4 inhibitors causes co-operative inhibitory responses on cell growth. However, while MEK and BRD4 inhibitors converge in the downregulation of genes associated with cancer-acquired super-enhancers, NSD2 inhibition affects the expression of clusters of genes embedded in megabase-scale regions marked with H3K36me2 and that contribute to the RAS transcription program. Thus, combinatorial therapies using MEK or BRD4 inhibitors together with NSD2 inhibition are likely to be needed to ensure a more comprehensive inhibition of oncogenic RAS-driven transcription programs in lung cancers with NSD2 overexpression.

Topics: Animals; Azepines; Benzamides; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Diphenylamine; Enhancer Elements, Genetic; Enzyme Inhibitors; Epigenesis, Genetic; Gene Expression; Gene Knockdown Techniques; Genes, ras; Histone-Lysine N-Methyltransferase; Histones; Humans; Lung Neoplasms; MAP Kinase Kinase Kinases; Methylation; Mice; Mice, Nude; Nuclear Proteins; Repressor Proteins; Transcription Factors; Transcription, Genetic; Triazoles; Xenograft Model Antitumor Assays

Several receptor tyrosine kinases (RTKs) including EGFR, ALK, and MET have been identified as therapeutic targets in non-small cell lung cancer (NSCLC). Among the downstream pathways of RTKs, the MAPK pathway is particularly important for cancer cell proliferation, differentiation, and survival. In this study, the effects of MEK inhibitors (trametinib and PD0325901) in several NSCLC cell lines with driver gene alterations, especially RTK genes, were tested in vitro using an MTT assay, and a wide range of sensitivities was found. In particular, all the EGFR-mutated cell lines were resistant to MEK inhibitors, whereas all the MET-amplified cell lines were sensitive. A bioinformatics technique and western blot analyses showed that the PI3K/AKT pathway is more activated in EGFR-mutated NSCLC than in MET-amplified NSCLC, and a PI3K inhibitor enhanced the sensitivity to trametinib in the EGFR-mutated cell lines, suggesting that this pathway is associated with resistance to MEK inhibitors. Although the HCC827 cell line (EGFR mutation) was resistant to MEK inhibitors, the HCC827CNXR cell line, whose driver gene shifts from EGFR to MET, exhibited enhanced sensitivity to MEK inhibitors, indicating the biological importance of the MAPK pathway for MET-amplified NCSLC. Furthermore, a synergistic effect of crizotinib (a MET inhibitor) and trametinib was observed in MET-amplified NCLC cell lines. Our findings indicate that the MAPK pathway is biologically important for MET-amplified NSCLC and strongly encourage the development of combination therapy with a MET inhibitor and a MEK inhibitor against MET-amplified NSCLC.

Topics: A549 Cells; Antineoplastic Agents; Benzamides; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Crizotinib; Diphenylamine; ErbB Receptors; Humans; Lung Neoplasms; MAP Kinase Kinase 1; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-met; Pyrazoles; Pyridines; Pyridones; Pyrimidinones

Lung cancer is the leading cause of cancer deaths, and effective treatments are urgently needed. Loss-of-function mutations in the DNA damage response kinase ATM are common in lung adenocarcinoma but directly targeting these with drugs remains challenging. Here we report that ATM loss-of-function is synthetic lethal with drugs inhibiting the central growth factor kinases MEK1/2, including the FDA-approved drug trametinib. Lung cancer cells resistant to MEK inhibition become highly sensitive upon loss of ATM both in vitro and in vivo. Mechanistically, ATM mediates crosstalk between the prosurvival MEK/ERK and AKT/mTOR pathways. ATM loss also enhances the sensitivity of KRAS- or BRAF-mutant lung cancer cells to MEK inhibition. Thus, ATM mutational status in lung cancer is a mechanistic biomarker for MEK inhibitor response, which may improve patient stratification and extend the applicability of these drugs beyond RAS and BRAF mutant tumours.

Topics: Animals; Ataxia Telangiectasia Mutated Proteins; Benzamides; Cell Line, Tumor; Cell Proliferation; Diphenylamine; Humans; Lung Neoplasms; Mice, Nude; Mutation; Protein Kinase Inhibitors; Proto-Oncogene Proteins B-raf; Pyridones; Pyrimidinones; ras Proteins; RNA Interference; Thiophenes; Urea; Xenograft Model Antitumor Assays

Acquired resistance to erlotinib in patients with EGFR-mutant non-small cell lung cancer can result from aberrant activation of alternative receptor tyrosine kinases, such as the HGF-driven c-MET receptor. We sought to determine whether inhibition of AKT signaling could augment erlotinib activity and abrogate HGF-mediated resistance.. The effects of MK-2206, a selective AKT inhibitor, were evaluated in combination with erlotinib on a large panel of 13 lung cancer cell lines containing different EGFR or KRAS abnormalities. The activity of the combination was assessed using proliferation assays, flow cytometry and immunoblotting. The MEK inhibitor PD0325901 was used to determine the role of the MAP kinase pathway in erlotinib resistance.. The combination of MK-2206 and erlotinib resulted in synergistic growth inhibition independent of EGFR mutation status. In cell lines where HGF blocked the anti-proliferative and cytotoxic effects of erlotinib, MK-2206 could restore cell cycle arrest, but MEK inhibition was required for erlotinib-dependent apoptosis. Both AKT and MEK inhibition contributed to cell death independent of erlotinib in the T790M-containing H1975 and the EGFR-WT cell lines tested.. These findings illustrate the potential advantages and challenges of combined signal transduction inhibition as a generalized strategy to circumvent acquired erlotinib resistance.

Topics: Apoptosis; Benzamides; Carcinoma, Non-Small-Cell Lung; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Cell Survival; Diphenylamine; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Drug Synergism; ErbB Receptors; Erlotinib Hydrochloride; Flow Cytometry; Hepatocyte Growth Factor; Heterocyclic Compounds, 3-Ring; Humans; Immunoblotting; Lung Neoplasms; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mutation; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Quinazolines; ras Proteins

The PI3K-AKT pathway is expected to be a therapeutic target for non-small cell lung cancer (NSCLC) treatment. We previously reported that a novel PI3K inhibitor iMDK suppressed NSCLC cells in vitro and in vivo without harming normal cells and mice. Unexpectedly, iMDK activated the MAPK pathway, including ERK, in the NSCLC cells. Since iMDK did not eradicate such NSCLC cells completely, it is possible that the activated MAPK pathway confers resistance to the NSCLC cells against cell death induced by iMDK. In the present study, we assessed whether suppressing of iMDK-mediated activation of the MAPK pathway would enhance anti-tumorigenic activity of iMDK. PD0325901, a MAPK inhibitor, suppressed the MAPK pathway induced by iMDK and cooperatively inhibited cell viability and colony formation of NSCLC cells by inducing apoptosis in vitro. HUVEC tube formation, representing angiogenic processes in vitro, was also cooperatively inhibited by the combinatorial treatment of iMDK and PD0325901. The combinatorial treatment of iMDK with PD0325901 cooperatively suppressed tumor growth and tumor-associated angiogenesis in a lung cancer xenograft model in vivo. Here, we demonstrate a novel treatment strategy using iMDK and PD0325901 to eradicate NSCLC.

Topics: Animals; Antineoplastic Agents; Benzamides; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Coumarins; Diphenylamine; Drug Synergism; Female; Human Umbilical Vein Endothelial Cells; Humans; Lung Neoplasms; Mice, Inbred BALB C; Mice, Nude; Mitogen-Activated Protein Kinase Kinases; Neovascularization, Pathologic; Phosphoinositide-3 Kinase Inhibitors; Thiazoles; Xenograft Model Antitumor Assays

Genomic analyses of squamous cell carcinoma (SCC) have yet to yield significant strategies against pathway activation to improve treatment. Platinum-based chemotherapy remains the mainstay of treatment for SCC of different histotypes either as a single-agent or alongside other chemotherapeutic drugs or radiotherapy; however, resistance inevitably emerges, which limits the duration of treatment response. To elucidate mechanisms that mediate resistance to cisplatin, we compared drug-induced perturbations to gene and protein expression between cisplatin-sensitive and -resistant SCC cells, and identified MAPK-ERK pathway upregulation and activation in drug-resistant cells. ERK-induced resistance appeared to be activated by Son of Sevenless (SOS) upstream, and mediated through Bim degradation downstream. Clinically, elevated p-ERK expression was associated with shorter disease-free survival in patients with locally advanced head and neck SCC treated with concurrent chemoradiation. Inhibition of MEK/ERK, but not that of EGFR or RAF, augmented cisplatin sensitivity in vitro and demonstrated efficacy and tolerability in vivo. Collectively, these findings suggest that inhibition of the activated SOS-MAPK-ERK pathway may augment patient responses to cisplatin treatment.

Topics: Animals; Antineoplastic Agents; Apoptosis Regulatory Proteins; Bcl-2-Like Protein 11; Benzamides; Blotting, Western; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Survival; Cisplatin; Diphenylamine; Drug Resistance, Neoplasm; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; MAP Kinase Signaling System; Membrane Proteins; Mice, SCID; Mitogen-Activated Protein Kinase Kinases; Proteomics; Proto-Oncogene Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Son of Sevenless Proteins; Tumor Burden; Xenograft Model Antitumor Assays

Lung carcinogenesis is a multistep process in which normal lung epithelial cells are converted to cancer cells through the sequential acquisition of multiple genetic or epigenetic events. Despite the utility of current genetically engineered mouse (GEM) models of lung cancer, most do not allow temporal dissociation of the cardinal events involved in lung tumor initiation and cancer progression. Here we describe a novel two-switch GEM model for BRAF(V600E)-induced lung carcinogenesis allowing temporal dissociation of these processes. In mice carrying a Flp recombinase-activated allele of Braf (Braf(FA)) in conjunction with Cre-regulated alleles of Trp53, Cdkn2a, or c-MYC, we demonstrate that secondary genetic events can promote bypass of the senescence-like proliferative arrest displayed by BRAF(V600E)-induced lung adenomas, leading to malignant progression. Moreover, restoring or activating TP53 in cultured BRAF(V600E)/TP53(Null) or BRAF(V600E)/INK4A-ARF(Null) lung cancer cells triggered a G1 cell-cycle arrest regardless of p19(ARF) status. Perhaps surprisingly, neither senescence nor apoptosis was observed upon TP53 restoration. Our results establish a central function for the TP53 pathway in restricting lung cancer development, highlighting the mechanisms that limit malignant progression of BRAF(V600E)-initiated tumors.

Topics: Adenocarcinoma; Adenoma; Animals; Benzamides; Cell Cycle Checkpoints; Cell Proliferation; Cell Survival; Cyclin-Dependent Kinase Inhibitor p16; Diphenylamine; Disease Models, Animal; Gene Expression Regulation, Neoplastic; Gene Silencing; Lung Neoplasms; MAP Kinase Kinase Kinases; Mice, Transgenic; Proto-Oncogene Proteins B-raf; Tumor Suppressor Protein p53

Oncogenesis in non-small cell lung cancer (NSCLC) is regulated by a complex signal transduction network. Single-agent targeted therapy fails frequently due to treatment insensitivity and acquired resistance. In this study, we demonstrate that co-inhibition of the MAPK and SRC pathways using a PD0325901 and Saracatinib kinase inhibitor combination can abrogate tumor growth in NSCLC. PD0325901/Saracatinib at 0.25:1 combination was screened against a panel of 28 NSCLC cell lines and 68% of cell lines were found to be sensitive (IC50 < 2 μM) to this combination. In Snail1 positive NSCLC lines, the drug combination complementarily enhanced mesenchymal-epithelial transition (MET), increasing both E-cadherin and Plakoglobin expression, and reducing Snail1, FAK and PXN expression. In addition, the drug combination abrogated cell migration and matrigel invasion. The co-inhibition of MAPK and SRC induced strong G1/G0 cell cycle arrest in the NSCLC lines, inhibited anchorage independent growth and delayed tumor growth in H460 and H358 mouse xenografts. These data provide rationale for further investigating the combination of MAPK and SRC pathway inhibitors in advanced stage NSCLC.

Topics: Animals; Benzamides; Benzodioxoles; Cadherins; Carcinoma, Non-Small-Cell Lung; Cell Adhesion; Cell Cycle; Cell Movement; Cell Proliferation; Diphenylamine; Dose-Response Relationship, Drug; Drug Synergism; Epithelial-Mesenchymal Transition; Female; Humans; Immunoblotting; Lung Neoplasms; MAP Kinase Kinase 1; Mice, Inbred BALB C; Mice, Nude; Microscopy, Confocal; Protein Kinase Inhibitors; Quinazolines; src-Family Kinases; Tumor Burden; Xenograft Model Antitumor Assays

N-cadherin and HER2/neu were found to be co-expressed in invasive breast carcinomas. To test the contribution of N-cadherin and HER2 in mammary tumor metastasis, we targeted N-cadherin expression in the mammary epithelium of the MMTV-Neu mouse. In the context of ErbB2/Neu, N-cadherin stimulated carcinoma cell invasion, proliferation and metastasis. N-cadherin caused fibroblast growth factor receptor (FGFR) upmodulation, resulting in epithelial-to-mesenchymal transition (EMT) and stem/progenitor like properties, involving Snail and Slug upregulation, mammosphere formation and aldehyde dehydrogenase activity. N-cadherin potentiation of the FGFR stimulated extracellular signal regulated kinase (ERK) and protein kinase B (AKT) phosphorylation resulting in differential effects on metastasis. Although ERK inhibition suppressed cyclin D1 expression, cell proliferation and stem/progenitor cell properties, it did not affect invasion or EMT. Conversely, AKT inhibition suppressed invasion through Akt 2 attenuation, and EMT through Snail inhibition, but had no effect on cyclin D1 expression, cell proliferation or mammosphere formation. These findings suggest N-cadherin/FGFR has a pivotal role in promoting metastasis through differential regulation of ERK and AKT, and underscore the potential for targeting the FGFR in advanced ErbB2-amplified breast tumors.

Topics: Aldehyde Dehydrogenase; Animals; Benzamides; Breast Neoplasms; Cadherins; Cell Movement; Cell Proliferation; Cyclin D1; Diphenylamine; Epithelial-Mesenchymal Transition; Extracellular Signal-Regulated MAP Kinases; Female; Humans; Lung Neoplasms; MAP Kinase Kinase 1; Mice; Mice, Transgenic; Neoplasm Invasiveness; Neoplasm Metastasis; Phosphorylation; Proto-Oncogene Proteins c-akt; Pyrimidines; Receptor, ErbB-2; Receptors, Fibroblast Growth Factor; RNA Interference; RNA, Small Interfering; Signal Transduction; Snail Family Transcription Factors; Spheroids, Cellular; Stem Cells; Transcription Factors; Tumor Cells, Cultured

The molecular mechanisms that control the balance between antiangiogenic and proangiogenic factors and initiate the angiogenic switch in tumors remain poorly defined. By combining chemical genetics with multimodal imaging, we have identified an autocrine feed-forward loop in tumor cells in which tumor-derived VEGF stimulates VEGF production via VEGFR2-dependent activation of mTOR, substantially amplifying the initial proangiogenic signal. Disruption of this feed-forward loop by chemical perturbation or knockdown of VEGFR2 in tumor cells dramatically inhibited production of VEGF in vitro and in vivo. This disruption was sufficient to prevent tumor growth in vivo. In patients with lung cancer, we found that this VEGF:VEGFR2 feed-forward loop was active, as the level of VEGF/VEGFR2 binding in tumor cells was highly correlated to tumor angiogenesis. We further demonstrated that inhibition of tumor cell VEGFR2 induces feedback activation of the IRS/MAPK signaling cascade. Most strikingly, combined pharmacological inhibition of VEGFR2 (ZD6474) and MEK (PD0325901) in tumor cells resulted in dramatic tumor shrinkage, whereas monotherapy only modestly slowed tumor growth. Thus, a tumor cell-autonomous VEGF:VEGFR2 feed-forward loop provides signal amplification required for the establishment of fully angiogenic tumors in lung cancer. Interrupting this feed-forward loop switches tumor cells from an angiogenic to a proliferative phenotype that sensitizes tumor cells to MAPK inhibition.

Topics: Animals; Antineoplastic Agents; Benzamides; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Transformation, Neoplastic; Diphenylamine; Feedback, Physiological; Humans; Lung Neoplasms; MAP Kinase Signaling System; Mice; Mice, Nude; Neovascularization, Pathologic; Piperidines; Quinazolines; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-2

Lung cancer is one of the leading cancer malignancies, with a five-year survival rate of only ~15%. We have developed a lentiviral-vector-mediated mouse model, which enables generation of non-small-cell lung cancer from less than 100 alveolar epithelial cells, and investigated the role of IKK2 and NF-κB in lung-cancer development. IKK2 depletion in tumour cells significantly attenuated tumour proliferation and significantly prolonged mouse survival. We identified Timp1, one of the NF-κB target genes, as a key mediator for tumour growth. Activation of the Erk signalling pathway and cell proliferation requires Timp-1 and its receptor CD63. Knockdown of either Ikbkb or Timp1 by short hairpin RNAs reduced tumour growth in both xenograft and lentiviral models. Our results thus suggest the possible application of IKK2 and Timp-1 inhibitors in treating lung cancer.

Topics: Animals; Benzamides; Cell Line, Tumor; Cell Proliferation; Diphenylamine; Disease Models, Animal; Female; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; I-kappa B Kinase; Kaplan-Meier Estimate; Lung Neoplasms; Male; MAP Kinase Signaling System; Mice; Mice, Knockout; Mice, Nude; Oligonucleotide Array Sequence Analysis; Proto-Oncogene Proteins p21(ras); Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Tetraspanin 30; Tissue Inhibitor of Metalloproteinase-1; Tumor Burden

Genetically engineered mouse (GEM) models of lung tumorigenesis allow careful evaluation of lung tumor initiation, progression, and response to therapy. Using GEM models of oncogene-induced lung cancer, we show the striking similarity of the earliest stages of tumorigenesis induced by KRAS(G12D) or BRAF(V600E). Cre-mediated expression of KRAS(G12D) or BRAF(V600E) in the lung epithelium of adult mice initially elicited benign lung tumors comprising cuboidal epithelial cells expressing markers of alveolar pneumocytes. Strikingly, in a head-to-head comparison, oncogenic BRAF(V600E) elicited many more such benign tumors and did so more rapidly than KRAS(G12D). However, despite differences in the efficiency of benign tumor induction, only mice with lung epithelium expression of KRAS(G12D) developed malignant non-small cell lung adenocarcinomas. Pharmacologic inhibition of mitogen-activated protein (MAP)-extracellular signal-regulated kinase (ERK) kinase (MEK)1/2 combined with in vivo imaging showed that initiation and maintenance of both BRAF(V600E)- or KRAS(G12D)-induced lung tumors was dependent on MEK→ERK signaling. Although the tumors dramatically regressed in response to MEK1/2 inhibition, they regrew following cessation of drug treatment. Together, our findings show that RAF→MEK→ERK signaling is both necessary and sufficient for KRAS(G12D)-induced benign lung tumorigenesis in GEM models. The data also emphasize the ability of KRAS(G12D) to promote malignant lung cancer progression compared with oncogenic BRAF(V600E).

Topics: Adenocarcinoma; Adenocarcinoma of Lung; Animals; Antineoplastic Agents; Benzamides; Carcinoma, Non-Small-Cell Lung; Cell Proliferation; Diphenylamine; Disease Models, Animal; Extracellular Signal-Regulated MAP Kinases; Lung Neoplasms; MAP Kinase Kinase 1; MAP Kinase Kinase 2; MAP Kinase Signaling System; Mice; Mice, Transgenic; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins p21(ras); Respiratory Mucosa; Tumor Cells, Cultured

The role of PI3K and MAPK pathways in tumor initiation and progression is well established; hence, several inhibitors of these pathways are currently in different stages of clinical trials. Recent studies identified a PI3K/mTOR (PF-04691502) and a MEK inhibitor (PD-0325901) with strong potency and efficacy in different cell lines and tumor models. PD-0325901, however, showed adverse effects when administered at or above MTD (maximum tolerated dose) in the clinic. Here, we show in preclinical models that PD-0325901 at doses well below MTD (sub-MTD 1.5 mg/kg SID) is still a potent compound as single agent or in combination with PF-04691502. We first observed that PD-0325901 at 1.5 mg/kg SID and in combination with PF-04691502 (7.5 mg/kg; SID) significantly inhibited growth of H460 (carry Kras and PIK3CA mutations) orthotopic lung tumors. Additionally, we tested efficacy of PD-0325901 in Kras(G12D-LSL) conditional GEMMs (genetically engineered mouse models) which are a valuable tool in translational research to study tumor progression. Intranasal delivery of adenoviruses expressing Cre recombinase (Adeno-Cre) resulted in expression of mutant Kras leading to development of tumor lesions in lungs including adenomatous hyperplasia, large adenoma, and adenocarcinoma. Similar to H460 tumors, PD-0325901 as single agent or in combination with PF-04691502 significantly inhibited growth of tumor lesions in lungs in Kras(G12D-LSL) mice when treatment started at adenocarcinoma stage (at 14 weeks post-Adeno-Cre inhalation). In addition, immunohistochemistry showed inhibition of pS6 (phosphorylated ribosomal S6) in the treated animals particularly in the combination group providing a proof of mechanism for tumor growth inhibition. Finally, m-CT imaging in live Kras(G12D-LSL) mice showed reduction of tumor burdens in PD-0325901-treated animals at sub-MTD dose. In conclusion, our data suggest that PD-0325901 at doses below MTD is still a potent compound capable of tumor growth inhibition where Kras and/or PI3K are drivers of tumor growth and progression.

Topics: Adenocarcinoma; Adenocarcinoma of Lung; Animals; Antineoplastic Combined Chemotherapy Protocols; Benzamides; Cell Line, Tumor; Diphenylamine; Dose-Response Relationship, Drug; Heterozygote; Humans; Lung Neoplasms; Maximum Tolerated Dose; Mice; Mice, Mutant Strains; Mitogen-Activated Protein Kinase Kinases; Neoplasm Transplantation; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins p21(ras); Pyridones; Pyrimidines; TOR Serine-Threonine Kinases

Mutational activation of KRAS is a common event in human tumors. Identification of the key signaling pathways downstream of mutant KRAS is essential for our understanding of how to pharmacologically target these cancers in patients. We show that PD0325901, a small-molecule MEK inhibitor, decreases MEK/ERK pathway signaling and destabilizes cyclin D1, resulting in significant anticancer activity in a subset of KRAS mutant tumors in vitro and in vivo. Mutational activation of PIK3CA, which commonly co-occurs with KRAS mutation, provides resistance to MEK inhibition through reactivation of AKT signaling. Genetic ablation of the mutant PIK3CA allele in MEK inhibitor-resistant cells restores MEK pathway sensitivity, and re-expression of mutant PIK3CA reinstates the resistance, highlighting the importance of this mutation in resistance to therapy in human cancers. In KRAS mutant tumors, PIK3CA mutation restores cyclin D1 expression and G(1)-S cell cycle progression so that they are no longer dependent on KRAS and MEK/ERK signaling. Furthermore, the growth of KRAS mutant tumors with coexistent PIK3CA mutations in vivo is profoundly inhibited with combined pharmacologic inhibition of MEK and AKT. These data suggest that tumors with both KRAS and phosphoinositide 3-kinase mutations are unlikely to respond to the inhibition of the MEK pathway alone but will require effective inhibition of both MEK and phosphoinositide 3-kinase/AKT pathway signaling.

Topics: Alleles; Animals; Benzamides; Cell Growth Processes; Cell Line, Tumor; Class I Phosphatidylinositol 3-Kinases; Colonic Neoplasms; Cyclin D1; Diphenylamine; Extracellular Signal-Regulated MAP Kinases; Gene Knockout Techniques; HCT116 Cells; Humans; Lung Neoplasms; MAP Kinase Kinase Kinases; MAP Kinase Signaling System; Mice; Mutation; Pancreatic Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins p21(ras); ras Proteins

Lung cancer is a genetically heterogeneous disease characterized by the acquisition of somatic mutations in numerous protein kinases, including components of the rat sarcoma viral oncogene homolog (RAS) and AKT signaling cascades. These pathways intersect at various points, rendering this network highly redundant and suggesting that combined mitogen-activated protein/extracellular signal-regulated kinase (MEK) and mammalian target of rapamycin (mTOR) inhibition may be a promising drug combination that can overcome its intrinsic plasticity. The MEK inhibitors, CI-1040 or PD0325901, in combination with the mTOR inhibitor, rapamycin, or its analogue AP23573, exhibited dose-dependent synergism in human lung cancer cell lines that was associated with suppression of proliferation rather than enhancement of cell death. Concurrent suppression of MEK and mTOR inhibited ribosomal biogenesis by 40% within 24 h and was associated with a decreased polysome/monosome ratio that is indicative of reduced protein translation efficiency. Furthermore, the combination of PD0325901 and rapamycin was significantly superior to either drug alone or PD0325901 at the maximum tolerated dose in nude mice bearing human lung tumor xenografts or heterotransplants. Except for a PTEN mutant, all tumor models had sustained tumor regressions and minimal toxicity. These data (a) provide evidence that both pathways converge on factors that regulate translation initiation and (b) support therapeutic strategies in lung cancer that simultaneously suppress the RAS and AKT signaling network.

Topics: Animals; Benzamides; Carcinoma, Non-Small-Cell Lung; Cell Death; Cell Proliferation; Diphenylamine; Drug Synergism; Drug Therapy, Combination; Feedback, Physiological; Humans; Immunoblotting; Immunosuppressive Agents; Lung Neoplasms; Mice; Mice, Nude; Mitogen-Activated Protein Kinase Kinases; Peptide Chain Initiation, Translational; Protein Kinases; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases