pd-0325901 and Carcinoma--Squamous-Cell

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

Dynamin-related protein 1 (Drp1) mediates mitochondrial fission. Recently, several studies have shown that Drp1 plays an important role in some cancers. However, little is known about Drp1 in cutaneous squamous cell carcinoma (SCC).. To investigate the role of Drp1 in the tumorigenesis of cutaneous SCCs.. We investigated cell proliferation, cell cycle, mitochondrial morphology, and MAPK signaling pathway using cutaneous SCC A431 and DJM1 cells that were transfected with shRNA vectors targeting Drp1. The Drp1 gene-knockdown SCC cells showed lower cell proliferation than scramble-control cells, as assessed by direct cell counting and clonogenic assays. DNA content analysis showed Drp1 knockdown to cause G2/M arrest. Morphologically, the depletion of Drp1 resulted in an elongated, hyper-fused mitochondrial network. The MEK inhibitor PD325901 suppressed cell proliferation, as well as inhibiting the phosphorylation of ERK. Our results reveal a crucial function for Drp1 in regulating tumor growth, mitochondrial morphology, and cell cycle in cutaneous SCC, suggesting that Drp1 could be a novel target for skin tumor therapies.

Topics: Aged; Aged, 80 and over; Animals; Benzamides; Carcinogenesis; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Diphenylamine; Dynamins; Female; G2 Phase Cell Cycle Checkpoints; Gene Knockdown Techniques; GTP Phosphohydrolases; Humans; Male; MAP Kinase Signaling System; Mice; Mice, Inbred BALB C; Mice, Nude; Microtubule-Associated Proteins; Middle Aged; Mitochondria; Mitochondrial Dynamics; Mitochondrial Proteins; Neoplasm Staging; Phosphorylation; Quinazolinones; RNA Interference; RNA, Small Interfering; Skin Neoplasms; Xenograft Model Antitumor Assays

Despite new radiotherapeutic strategies, radioresistance in head and neck squamous cell carcinoma (HNSCC) remains a major problem. Preclinical model systems are needed to identify resistance mechanisms in this heterogeneous entity.. We elucidated the interplay among mitogen-activated protein kinase (MAPK)-inhibition, radiation, and p53 mutations in vitro and in a novel ex vivo model derived from vital human HNSCC samples. HNSCC cell lines (p53WT/mut) were treated with the mitogen-activated protein kinase (MEK)-inhibitor PD-0325901 and subsequently irradiated. Radiosensitization was functionally assessed and evaluated in the ex vivo model.. We observed a pronounced irradiation-induced extracellular signal-regulated kinase (ERK) phosphorylation in 2 cell lines, which was independent of their p53 mutation status and associated with PD-0325901-related radiosensitization in a clonogenic assay. Heterogeneity in irradiation-induced ERK phosphorylation and in radiosensitization after MEK-inhibition was also reflected in the ex vivo model.. We provide experimental evidence for radiosensitizing effects of PD-0325901 in HNSCC. The ex vivo culture technology might offer a promising tool for individualized drug efficacy testing. © 2016 Wiley Periodicals, Inc. Head Neck 38: E2049-E2061, 2016.

Topics: Adult; Aged; Benzamides; Carcinoma, Squamous Cell; Cell Line, Tumor; Diphenylamine; Extracellular Signal-Regulated MAP Kinases; Female; Head and Neck Neoplasms; Humans; Male; MAP Kinase Signaling System; Middle Aged; Phosphorylation; Radiation Tolerance; Radiation-Sensitizing Agents; Tumor Suppressor Protein p53

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

Head and neck squamous cell carcinomas exhibit variable sensitivity to inhibitors of the PI3K/mTOR pathway, an important target of genomic alterations in this cancer type. The mitogen-activated protein kinase kinase (MEK)/ERK/activator protein 1 (AP-1) and nuclear factor-κB (NF-κB) pathways are also frequently co-activated, but their roles in resistance mechanisms to PI3K/mTOR inhibitors and as therapeutic targets in head and neck squamous cell carcinoma (HNSCC) are not well defined.. We determined the IC50s of dual PI3K/mTOR inhibitor PF-05212384 (PF-384) by XTT assays in 14 HNSCC lines with PI3K/Akt/mTOR cascade alterations. In two resistant models, we further characterized the molecular, cellular, and in vivo attributes and effects of combining PF-384 with MEK inhibitor PD-0325901 (PD-901).. PF-384 IC50s varied between 0.75 and 133 nmol/L in 14 HNSCC lines with overexpression or mutations of PIK3CA, and sensitivity correlated with increased phospho-AKT(T308/S473). In resistant UMSCC-1 and -46 models, PF-384 increased G0-/G1-phase accumulation but weakly induced sub-G0 cell death. PF-384 inhibited direct targets of PI3K/mTOR, but incompletely attenuated co-activated ERK and UMSCC-1 xenograft growth in vivo. PD-901 strongly inhibited MEK/ERK targets, and the combination of PF-384 and PD-901 inhibited downstream NF-κB and AP-1 transactivation, and IL8 and VEGF production in vitro. PD-901 potently inhibited tumor growth alone and with PF384, enhanced antiproliferative, apoptotic, and anti-angiogenesis activity in vivo.. PI3K/mTOR inhibitor PF-384 exhibits variable activity in a panel of HNSCC cell lines with differing PIK3CA expression and mutation status. MEK inhibitor PD-901 overcomes resistance and enhances antitumor effects observed with PF-384 in vivo.

Topics: Animals; Antineoplastic Agents; Benzamides; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cell Transformation, Neoplastic; Cytokines; Diphenylamine; Disease Models, Animal; Drug Resistance, Neoplasm; Drug Synergism; Gene Expression; Genes, Reporter; Head and Neck Neoplasms; Humans; Inflammation Mediators; Mitogen-Activated Protein Kinase Kinases; Morpholines; NF-kappa B; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Kinase Inhibitors; Signal Transduction; Squamous Cell Carcinoma of Head and Neck; TOR Serine-Threonine Kinases; Transcription Factor AP-1; Transcriptional Activation; Triazines; Xenograft Model Antitumor Assays