alvocidib and Adenocarcinoma

Breast cancer is the most commonly diagnosed cancer in American women. The underlying mechanisms that cause aberrant cell proliferation and tumor growth involve conserved pathways, which include components of the cell cycle machinery. Proto-oncogenes, growth factors, and steroids have been implicated in the pathogenesis of breast cancer. Surgery, local irradiation, and chemotherapy have been the mainstay of treatment for early and advanced stage disease. Potential targets for selective breast cancer therapy are herein reviewed. Improved understanding of the biology of breast cancer has led to more specific "targeted therapies" directed at biological processes that are selectively deregulated in the cancerous cells. Examples include tamoxifen for estrogen receptor positive tumors and imunoneutralizing antibodies such as trastuzumab for Her2/neu overexpressing tumors. Other novel anticancer agents such as paclitaxel, a microtubule binding molecule, and flavopiridol, a cyclin dependent kinase inhibitor, exert their anticancer effects by inhibiting cell cycle progression.

Topics: Adenocarcinoma; Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Breast Neoplasms; Cell Cycle; Cell Cycle Proteins; Cyclin-Dependent Kinase Inhibitor p27; Cyclins; Databases, Factual; Enzyme Inhibitors; Flavonoids; Humans; Microtubule-Associated Proteins; Neovascularization, Pathologic; Oncogenes; Paclitaxel; Piperidines; Receptors, Estrogen; Tamoxifen; Transforming Growth Factor beta; Trastuzumab; Tumor Suppressor Proteins

Molecular analysis of malignant transformation in Barrett's epithelium provides insight into the temporal nature and significance of individual genetic events during multistep esophageal carcinogenesis. Potential targets for intervention in esophageal neoplasms include mutations involving retinoblastoma (Rb) and p53 tumor-suppressor pathways as well as tyrosine kinase cascades, which are known to promote cell cycle progression. Data from recent experiments provide the preclinical rationale for novel pharmacologic interventions in established esophageal cancers, and suggest strategies for chemoprevention in patients at risk for the development of these neoplasms.

Topics: Adenocarcinoma; Adenoviridae; Antineoplastic Agents; Barrett Esophagus; Cell Transformation, Neoplastic; Esophageal Neoplasms; Flavonoids; Genes, p53; Genetic Vectors; Humans; Piperidines; Precancerous Conditions

Pancreatic adenocarcinoma (PC) harbors frequent alterations in p16, resulting in cell cycle dysregulation. A phase I study of docetaxel and flavopiridol, a pan-cyclin-dependent kinase inhibitor, demonstrated encouraging clinical activity in PC. This phase II study was designed to further define the efficacy and toxicity of this regimen in patients with previously treated PC.. Patients with gemcitabine-refractory, metastatic PC were treated with docetaxel 35 mg/m(2) followed by flavopiridol 80 mg/m(2) on days 1, 8, and 15 of a 28-day cycle. Tumor measurements were performed every two cycles. A Simon two-stage design was used to evaluate the primary endpoint of response.. Ten patients were enrolled, and 9 were evaluable for response. No objective responses were observed; however, 3 patients (33%) achieved transient stable disease, with one of these patients achieving a 20% reduction in tumor size. Median survival was 4.2 months, with no patients alive at the time of analysis. Adverse events were significant, with 7 patients (78%) requiring >or=1 dose reduction for transaminitis (11%), grade 4 neutropenia (33%), grade 3 fatigue (44%), and grade 3 diarrhea (22%).. The combination of flavopiridol and docetaxel has minimal activity and significant toxicity in this patient population. These results reflect the challenges of treating patients with PC in a second-line setting where the risk/benefit equation is tightly balanced.

Topics: Adenocarcinoma; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Docetaxel; Female; Flavonoids; Humans; Male; Middle Aged; Pancreatic Neoplasms; Piperidines; Taxoids; Treatment Outcome

A phase II study was conducted to determine the efficacy of single agent flavopiridol therapy in patients with recurrent or persistent endometrial adenocarcinoma refractory to established treatments.. Eligible patients with measurable disease who failed primary therapy including one cytotoxic regimen were eligible for the trial. They were treated with single agent flavopiridol (50 mg/m(2)/day, IV bolus days 1, 2, 3). Treatment was repeated every 21 days with dose adjustments made for toxicity. Patients were treated until progression of disease or adverse side effects precluded further therapy.. A total of 26 patients were enrolled in the study of whom, 23 patients were eligible. There were no objective responses. Five patients had stable disease (22%), 15 (65%) had increasing disease, and response could not be assessed in 3 (13%). The most frequent side effects included anemia, neutropenia, and diarrhea, all of which appeared manageable.. Flavopiridol as a single agent in the above dosing schedule appears to have minimal activity as second-line chemotherapy of endometrial adenocarcinoma.

Topics: Adenocarcinoma; Adult; Aged; Antineoplastic Agents; Endometrial Neoplasms; Female; Flavonoids; Humans; Middle Aged; Neoplasm Recurrence, Local; Piperidines

Flavopiridol is the first cyclin-dependent kinase inhibitor to enter clinical trials. Activity in gastric cancer xenografts and in a patient with gastric cancer on the phase I trial led to this phase II study of flavopiridol in patients with metastatic gastric cancer.. Sixteen patients were entered onto the study, and 14 were assessable for response. Flavopiridol was administered initially at a dose of 50 mg/m(2)/d by continuous infusion for 72 hours every 2 weeks. Assessment of plasma pharmacokinetics was performed in all patients. Peripheral mononuclear cells were collected throughout the 72-hour infusion for determinants of apoptosis.. There were no major objective responses (exact confidence interval 0% to 23%). One patient achieved a minor response in his liver metastases, though the primary progressed. Other patients exhibited histologic and radiographic evidence of tumor necrosis. Common toxicities included fatigue in 93% of patients (grade 3 or 4 in 27%) and diarrhea in 73% of patients (grade 3 or 4 in 20%). Five patients (33%) developed venous thromboses at the central catheter tip. The studies performed on peripheral mononuclear cells indicated no induction of apoptosis.. Flavopiridol administered as a single agent for 72 hours every 14 days is inactive in the treatment of gastric cancer. The drug also induced an unexpected higher incidence of vascular thrombosis and fatigue than was anticipated from the phase I trials. Future development of flavopiridol will depend on other doses and schedules in combination with chemotherapy.

Topics: Adenocarcinoma; Adult; Aged; Antineoplastic Agents; Cyclin-Dependent Kinases; Fatigue; Female; Flavonoids; Humans; Infusions, Intravenous; Male; Middle Aged; Piperidines; Stomach Neoplasms; Venous Thrombosis

Role of cyclin dependent kinase 9(CDK9) as a potential target in esophageal adenocarcinoma (EAC) is unknown. We investigated CDK9 protein expression in EAC and Barrett's esophagus and role of CDK9 in oncogenic processes of EAC in vitro and in murine xenografts. The CDK9 expression was significantly higher in EAC as compared to Barrett's esophagus in patient samples. Stable shCDK9 in SKGT4 reduced proliferation by 37% at day 4, increased apoptosis at 48 hours and induced G1 cell cycle arrest at 48 hours (58.4% vs. 45.8%) compared to controls SKGT4 cells. SKGT4-shCDK9 cell-derived tumors were significantly smaller than control SKGT4-derived tumors in xenografts (72.89mm3 vs. 270mm3). Pharmaceutical inhibition of CDK9 by Flavopiridol (0.1µm for 48 hours) and CAN508 (20 and 40µm for 72 hours) induced significant reduction in proliferation and 2-fold increase in apoptosis in SKGT4, FLO1 and OE33 cells. In xenograft models, CAN508 (60 mg/kg/dayx10 days) and Flavopiridol (4mg/kg/dayx10 days) caused 50.8% and 63.1% reduction in xenograft tumors as compared to control on post-treatment day 21. Reduction of MCL-1 and phosphorylated RNA polymerase II was observed with transient shCDK9 in SKGT4 cells but not with stable shCDK9. CAN508 (20 and 40 µm) and Flavopiridol (0.1, 0.2 and 0.3 µm) for 4 hours showed reduction in MCL-1 mRNA (84% and 96%) and protein. Mcl-1 overexpression conferred resistance to Flavopiridol (0.2 µm or 0.4 µm for 48 hours) and CAN 508 (20 or 40µm for 72 hours). Chromatin immunoprecipitation demonstrated significant reduction of binding of transcriptional factor HIF-1α to MCL-1 promoter in FLO-1 cells by CDK9 inhibitors.

Topics: Adenocarcinoma; Aged; Aged, 80 and over; Animals; Apoptosis; Barrett Esophagus; Carcinogenesis; Cell Line, Tumor; Cyclin-Dependent Kinase 9; Esophageal Neoplasms; Female; Flavonoids; Gene Expression Regulation, Neoplastic; Humans; Male; Mice, Nude; Middle Aged; Myeloid Cell Leukemia Sequence 1 Protein; Piperidines; RNA, Small Interfering; Xenograft Model Antitumor Assays

Concurrent chemo-radiotherapy before surgery is standard treatment protocol for esophageal cancer with a less than 30% complete response due to resistance to therapy. The aim of this study was to determine whether molecular targeting approach using an inhibitor of cyclin-dependent kinases, flavopiridol, can help overcome the resistance to radiotherapy.. SEG-1 cells (human esophageal adenocarcinoma) were exposed to gamma-rays with and without flavopiridol treatment and assayed for clonogenic survival, apoptosis, cell cycle distribution, and Western blot analysis. Efficacy of flavopiridol in enhancing tumor response to radiation was determined by tumor growth delay assay using SEG-1 tumor xenografts generated in nude mice.. The clonogenic cell survival assay data showed that flavopiridol (300 nM, 24h), when given either before or after radiation, significantly enhanced the radiosensitivity of SEG-1 cells. The cells were accumulated at G1 phase of the cell cycle by flavopiridol that was associated with downregulation of p-cdk-1, p-cdk-2, cyclin D1 and p-Rb expression. Flavopiridol by itself induced apoptosis in SEG-1 cells and also enhanced the radiation-induced apoptosis, associated with an increase in cleaved poly ADP-ribose polymerase. Reduction in phosphorylation of RNA polymerase II by flavopiridol suggested that flavopiridol inhibited the transcriptional activity. In vivo studies with SEG-1 tumor xenografts showed that flavopiridol, either given before or after radiation, greatly enhanced the effect of tumor irradiation.. Flavopiridol treatment significantly enhanced SEG-1 cell radiosensitivity as well as the radioresponse of SEG-1 tumor xenografts. The underlying mechanisms are multiple, including cell cycle redistribution, apoptosis, and transcriptional inhibition. These preclinical data suggest that flavopiridol has the potential to increase the radioresponse of esophageal adenocarcinomas.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Apoptosis; Cell Cycle; Cell Growth Processes; Cell Line, Tumor; Combined Modality Therapy; Cyclin-Dependent Kinases; Dose-Response Relationship, Drug; Esophageal Neoplasms; Flavonoids; Humans; Mice; Mice, Nude; Piperidines; Protein Kinase Inhibitors; Radiation Tolerance; Xenograft Model Antitumor Assays

Clinical treatment of solid tumors with docetaxel, flavopiridol, or 5-fluorouracil (5-FU) often encounters undesirable side effects and drug resistance. This study aims to evaluate the potential role of combination therapy with docetaxel, flavopiridol, or 5-FU in modulating chemosensitivity and better understand how they might be used clinically.. HCT116 colon cancer cells were treated with docetaxel, flavopiridol, and 5-FU in several different administrative schedules in vitro, either sequentially or simultaneously. Cell survival was measured by MTT assay. The activity of caspase-3 was determined by caspase-3 assays and the soft agar colony assay was used to test the colony formation of HCT116 cells in soft agar. We also established xenograft models to extend in vitro observations to an in vivo system.. The maximum cytotoxicity was found when human colon cancer HCT116 cells were treated with docetaxel for 1 h followed by flavopiridol for 24 h and 5-FU for another 24 h. This sequential combination therapy not only inhibits tumor cell growth more strongly compared to other combination therapies but also significantly reduces colony formation in soft agar and augments apoptosis of HCT116 cells. Sequencing of docetaxel followed 1 h later by flavopiridol, followed 24 h later by 5-FU in xenograft models, also resulted in delayed tumor growth and higher survival rate.. These results highlight the importance of an administrative schedule when combining docetaxel with flavopiridol and 5-FU, providing a rationale explanation for its development in clinical trials.

Topics: Adenocarcinoma; Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Proliferation; Colonic Neoplasms; Docetaxel; Female; Flavonoids; Fluorouracil; HCT116 Cells; Humans; Mice; Mice, Nude; Neoplasm Transplantation; Piperidines; Taxoids

The cyclin-dependent kinase (cdk) inhibitor p27 preferentially inactivates cdk complexes required for progression through the G1/S transition. Loss of p27 is associated with aggressive behavior in a variety of tumors, including Barrett's associated adenocarcinoma (BAA). We have previously shown that gastroduodenal-esophageal reflux (GDER) together with N-methyl-N-benzylnitrosamine (MBN) induces Barrett's esophagus (BE) and malignant transformation of the esophageal mucosa in mice. This process is enhanced in a p27 null background. Here, we show that chronic flavopiridol administration sharply reduced the prevalence of BE in GDER/MBN-treated p27 knockout mice when compared to animals treated with diluent only (7 vs 26%, P=0.0079). Similarly, flavopiridol reduced the prevalence of BAA (11 vs 32%, P=0.0098) and overall cancer prevalence (15 vs 60%, P<0.0001). In addition, appropriate molecular targeting by flavopiridol in tumor cells was confirmed by downregulation of cyclin D1, a known target of this pan-cdk inhibitor. The results of this study represent the experimental basis for chemoprevention with cdk inhibitors in human BE and BAA.

Topics: Adenocarcinoma; Animals; Anticarcinogenic Agents; Barrett Esophagus; Carcinoma, Squamous Cell; Cell Cycle Proteins; Cell Transformation, Neoplastic; Cyclin D1; Cyclin-Dependent Kinase Inhibitor p27; Esophageal Neoplasms; Flavonoids; Mice; Phosphorylation; Piperidines; Retinoblastoma Protein; Tumor Suppressor Proteins

Flavopiridol is the potent inhibitor of cdks sharing its function with endogenous cdk inhibitors, and causes arrest at both the G1 and G2 phases of the cell cycle resulting in apoptosis in various tumor cell lines. Cyclin-dependent kinase inhibitor p16INK4a induces cell cycle arrest in G1 or G2 or both, and is inactivated in many malignant tumors. In this study, we focused on the effects of flavopiridol on chemically-induced rat lung adenocarcinoma, osteosarcoma and malignant fibrous histiocytoma (MFH) cell lines showing different pattern of p16INK4a status. The data demonstrated that flavopiridol inhibited cellular growth in a dose- and time-dependent manner, inducing apoptosis within 24 h in all cell lines at a concentration of 300 nM. The growth inhibition rate was the greatest for lung adenocarcinoma cells, lacking p16INK4a expression associated with methylation-mediated gene silencing; 83% at a concentration of 300 nM for 72-h treatment; while the growth of osteosarcoma and MFH cells, both expressing p16INK4a, were inhibited at similar levels; 54-61% for osteosarcoma and 61-64% for MFH cell lines. Then, we further investigated the influence of p16INK4a induction upon the effect of flavopiridol in p16INK4a-deficient lung adenocarcinoma cells. 5-aza 2'-deoxycytidine (5-Aza-CdR) induced p16INK4a expression and inhibited cellular growth in lung adenocarcinoma at a similar level to that with flavopiridol treatment. After the induction of p16INK4a expression by 5-Aza-CdR, the growth inhibition rates of flavopiridol in the p16INK4a-induced lung adenocarcinoma cells could not achieve comparable inhibition to that in the p16INK4a-deficient cells; the efficacy was reduced compared to original p16INK4a-deficient cells at each concentration of 50, 100 and 500 nM for 72-h treatment. These data indicate that flavopiridol shows cell type specific inhibition and possibly acts in a more compensatory manner for endogenous p16INK4a function in tumor cells having the aberrations of p16INK4a gene.

Topics: Adenocarcinoma; Animals; Apoptosis; Bone Neoplasms; Cell Division; Cell Line, Tumor; Cyclin D1; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinase Inhibitor p16; Cyclin-Dependent Kinases; DNA Methylation; Flavonoids; Gene Expression Regulation, Neoplastic; Histiocytoma, Benign Fibrous; Lung Neoplasms; Osteosarcoma; Piperidines; Promoter Regions, Genetic; Proto-Oncogene Proteins; Rats; RNA, Messenger

The fraction of noncycling cells found in most tumors represents a major obstacle for conventional chemotherapy. Here, we show that the cyclin-dependent kinase inhibitor p27KIP-1 accumulates to high levels in human tumors grown in immunodeficient mice. We have developed an antisense phosphorothioate oligodeoxynucleotide (ODN) that efficiently inhibits the expression of p27KIP-1 both in vitro and in vivo. Treatment of cultured tumor cells with this ODN sensitized the cells to all chemotherapeutic drugs tested, including the new kinase inhibitor flavopiridol. Furthermore, striking synergistic effects of the p27KIP-1 ODN and flavopiridol were observed in vivo with respect to both the induction of apoptotic cell death and the inhibition of tumor growth. Importantly, p27KIP-1 ODN treatment alone did not provoke any detectable tumor enhancement. A mechanistic explanation for these findings might be derived from the observation that p27 ODN treatment of cultured tumor cells led to a clear increase in the fraction of S-G2 cells in the absence of an efficient progression into M phase. These findings may have direct relevance to the development of new approaches for the treatment of human cancer.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Cell Cycle; Cell Cycle Proteins; Cyclin-Dependent Kinase Inhibitor p27; Cyclin-Dependent Kinases; Drug Synergism; Flavonoids; HeLa Cells; Humans; Lung Neoplasms; Male; Mice; Mice, Nude; Microtubule-Associated Proteins; Mitosis; Oligonucleotides, Antisense; Piperidines; Prostatic Neoplasms; Thionucleotides; Transfection; Tumor Suppressor Proteins; Xenograft Model Antitumor Assays