Metastasis is the leading cause of death in patients with breast, lung, and head and neck cancers. However, the molecular mechanisms underlying metastases in these cancers remain unclear. We found that the p90 ribosomal S6 kinase 2 (RSK2)- cAMP response element-binding protein (CREB) pathway is commonly activated in diverse metastatic human cancer cells, leading to up-regulation of a CREB transcription target Fascin- 1. We also observed that the protein expression patterns of RSK2 and Fascin-1 correlate in primary human tumor tissue samples from head and neck squamous cell carcinoma patients. Moreover, knockdown of RSK2 disrupts filopodia formation and bundling in highly invasive cancer cells, leading to attenuated cancer cell invasion in vitro and tumor metastasis in vivo, whereas expression of Fascin-1 significantly rescues these phenotypes. Furthermore, targeting RSK2 with the small molecule RSK inhibitor FMK-MEA effectively attenuated the invasive and metastatic potential of cancer cells in vitro and in vivo, respectively. Taken together, our findings for the first time link RSK2-CREB signaling to filopodia formation and bundling through the up-regulation of Fascin-1, providing a proinvasive and prometastatic advantage to human cancers. Therefore, protein effectors of the RSK2-CREB-Fascin-1 pathway represent promising biomarkers and therapeutic targets in the clinical prognosis and treatment of metastatic human cancers.
Carfilzomib (CFZ) is a second generation proteasome inhibitor approved for the treatment of patients with multiple myeloma. It induces apoptosis in human cancer cells; but the underlying mechanisms remain undefined. In the present study, we show that CFZ decreases the survival of several human cancer cell lines and induces apoptosis. Induction of apoptosis by CFZ occurs, at least in part, due to activation of the extrinsic apoptotic pathway, since FADD deficiency protected cancer cells from undergoing apoptosis. CFZ increased total and cell surface levels of DR5 in different cancer cell lines; accordingly it enhanced TRAIL-induced apoptosis. DR5 deficiency protected cancer cells from induction of apoptosis by CFZ either alone or in combination with TRAIL. These data together convincingly demonstrate that DR5 upregulation is a critical mechanism accounting for CFZ-induced apoptosis and enhancement of TRAIL-induced apoptosis. CFZ inhibited the degradation of DR5, suggesting that DR5 stabilization contributes to CFZ-induced DR5 upregulation. In summary, the present study highlights the important role of DR5 upregulation in CFZ-induced apoptosis and enhancement of TRAIL-induced apoptosis in human cancer cells.
Background The benefit of combined chemoradiation in elderly patients with human papillomavirus (HPV)-positive locally advanced oropharyngeal squamous cell carcinoma (SCC) must be balanced with the potential for higher toxicity rates. We performed a retrospective review of our institutional experience. Methods Patients 70 years or older with p16-positive oropharyngeal SCC treated with definitive chemoradiation from 2005 to 2013 were evaluated. Overall survival (OS), disease-free survival (DFS), and locoregional failure-free survival were calculated. Results Twenty-one eligible patients had a follow-up of 22.4 months. Estimated 5-year OS, DFS, and locoregional failure-free survival were 76.0%, 40%, and 95%, respectively. There was 1 death from acute toxicity, and 50% had unplanned hospitalizations. Sixty percent had late toxicity, and 6-month feeding tube dependence was 25%. Conclusion Elderly patients with HPV-positive locally advanced SCC of the oropharynx treated with definitive chemoradiation had good OS but high rates of acute and long-term toxicity.
Objective: To explore biopsychosocial factors (beliefs, depression, catastrophizing cytokines) in individuals newly diagnosed with lung cancer and no pain to determine their relationship at diagnosis and across time and to determine whether these factors contribute to pain intensity or pain interference with function at pain onset. Materials and Methods: A longitudinal, exploratory, pilot study was implemented in a private medical center and a VA medical center in the southeast. Twelve subjects not experiencing pain related to cancer of the lung or its treatment were recruited. A Karnofsky status of 40% and hemoglobin of 8 g were required. Five questionnaires were completed and 10mL of blood was drawn at baseline; 4 questionnaires and blood draws were repeated monthly for 5 months. One baseline questionnaire and a pain assessment were added at final. Demographic, clinical, and questionnaire data were summarized; standardized scale scores were calculated. Results: Biopsychosocial scores that were low at baseline increased from T1-T4 but decreased slightly T5-T6. Individuals with higher pain intensity and higher pain interference at final had higher psychosocial scores at baseline than individuals with lower pain intensity and lower pain interference at final. Conclusions: Unrelated to disease stage, metastasis, or treatment, unique levels of biopsychosocial factors are observed in patients newly diagnosed with lung cancer who report higher levels of pain intensity and higher levels of pain interference at the time pain occurs. Replication studies are needed to validate this response pattern and determine the value of repeated individual assessments.
by
Shuguang Leng;
Guodong Wu;
Donna M. Klinge;
Cynthia L. Thomas;
Elia Casas;
Maria A. Picchi;
Christine A. Stidley;
Sandra J. Lee;
Seena Aisner;
Jill M. Siegfried;
Suresh Ramalingam;
Fadlo Khuri;
Daniel D. Karp;
Steven A. Belinsky
CT screening for lung cancer reduces mortality, but will cost Medicare ~2 billion dollars due in part to high false positive rates. Molecular biomarkers could augment current risk stratification used to select smokers for screening. Gene methylation in sputum reflects lung field cancerization that remains in lung cancer patients post-resection. This population was used in conjunction with cancer-free smokers to evaluate classification accuracy of a validated eight-gene methylation panel in sputum for cancer risk. Sputum from resected lung cancer patients (n=487) and smokers from Lovelace (n=1380) and PLuSS (n=718) cohorts was studied for methylation of an 8-gene panel. Area under a receiver operating characteristic curve was calculated to assess the prediction performance in logistic regressions with different sets of variables. The prevalence for methylation of all genes was significantly increased in the ECOG-ACRIN patients compared to cancer-free smokers as evident by elevated odds ratios that ranged from 1.6 to 8.9. The gene methylation panel showed lung cancer prediction accuracy of 82-86% and with addition of clinical variables improved to 87-90%. With sensitivity at 95%, specificity increased from 25% to 54% comparing clinical variables alone to their inclusion with methylation. The addition of methylation biomarkers to clinical variables would reduce false positive screens by ruling out one-third of smokers eligible for CT screening and could increase cancer detection rates through expanding risk assessment criteria.
Objective: This phase I trial was designed to determine the maximal tolerated dose (MTD) of the combination of topotecan and gemcitabine given in a weekly schedule.
Materials and Methods: In this single-arm, open label, dose-escalation study, we administered topotecan (0.75–1.5 mg/m2) and gemcitabine (1000 mg/m2) on days 1, 8, and 15 every 4 weeks to 25 patients with advanced solid tumors.
Results: The topotecan MTD, when combined with gemcitabine, was 1.25 mg/m2/wk. Dose-limiting toxicities consisted of febrile granulocytopenia in 2 patients at the highest dose level. At the MTD, no episodes of granulocytopenia were observed, whereas 2/9 patients exhibited grade 3 thrombocytopenia. Other common grades 3–4 adverse events across all cohorts included non-neutropenic infections, fatigue, skin reactions, vomiting, and fever. One partial response and 2 stable diseases were observed in patients with nasopharyngeal carcinoma. Disease stabilization was also observed in patients with squamous cell carcinoma of the head and neck (3), nonsmall cell lung cancer (1), and thymoma (1).
Conclusions: Topotecan and gemcitabine combined in a weekly schedule exhibit a favorable toxicity profile. Efficacy results support the further evaluation of this regimen in patients with head and neck cancer (particularly nasopharyngeal carcinoma).
Mitochondrial acetyl-CoA acetyltransferase 1 (ACAT1) regulates pyruvate dehydrogenase complex (PDC) by acetylating pyruvate dehydrogenase (PDH) and PDH phosphatase. How ACAT1 is “hijacked” to contribute to the Warburg effect in human cancer remains unclear. We found that active, tetrameric ACAT1 is commonly upregulated in cells stimulated by EGF and in diverse human cancer cells, where ACAT1 tetramers, but not monomers, are phosphorylated and stabilized by enhanced Y407 phosphorylation. Moreover, we identified arecoline hydrobromide (AH) as a covalent ACAT1 inhibitor that binds to and disrupts only ACAT1 tetramers. The resultant AH-bound ACAT1 monomers cannot reform tetramers. Inhibition of tetrameric ACAT1 by abolishing Y407 phosphorylation or AH treatment results in decreased ACAT1 activity, leading to increased PDC flux and oxidative phosphorylation with attenuated cancer cell proliferation and tumor growth. These findings provide a mechanistic understanding of how oncogenic events signal through distinct acetyltransferases to regulate cancer metabolism and suggest ACAT1 as an anti-cancer target.
Bcl-XL is a major antiapoptotic protein in the Bcl-2 family whose overexpression is more widely observed in human lung cancer cells than that of Bcl-2, suggesting that Bcl-XL is more biologically relevant and therefore a better therapeutic target for lung cancer. Here, we screened small molecules that selectively target the BH3 domain (aa 90-98) binding pocket of Bcl-XL using the UCSF DOCK 6.1 program suite and the NCI chemical library database. We identified two new Bcl-XL inhibitors (BXI-61 and BXI-72) that exhibit selective toxicity against lung cancer cells compared with normal human bronchial epithelial cells. Fluorescence polarization assay reveals that BXI-61 and BXI-72 preferentially bind to Bcl-XL protein but not Bcl2, Bcl-w, Bfl-1/A1, or Mcl-1 in vitro with high binding affinities. Treatment of cells with BXI-72 results in disruption of Bcl-XL/Bak or Bcl-XL/Bax interaction, oligomerization of Bak, and cytochrome c release from mitochondria. Importantly, BXI-61 and BXI-72 exhibit more potent efficacy against human lung cancer than ABT-737 but less degree in platelet reduction in vivo. BXI-72 overcomes acquired radioresistance of lung cancer. On the basis of our findings, the development of BXI(s) as a new class of anticancer agents is warranted and represents a novel strategy for improving lung cancer outcome.