dihydropyridines and Breast-Neoplasms

There is convincing epidemiological and experimental evidence that capsaicin, a potent natural transient receptor potential cation channel vanilloid member 1 (TRPV1) agonist, has anticancer activity. However, capsaicin cannot be given systemically in large doses, because of its induction of acute pain and neurological inflammation. MRS1477, a dihydropyridine derivative acts as a positive allosteric modulator of TRPV1, if added together with capsaicin, but is ineffective, if given alone. Addition of MRS1477 evoked Ca2+ signals in MCF7 breast cancer cells, but not in primary breast epithelial cells. This indicates that MCF7 cells not only express functional TRPV1 channels, but also produce endogenous TRPV1 agonists. We investigated the effects of MRS1477 and capsaicin on cell viability, caspase-3 and -9 activities and reactive oxygen species production in MCF7 cells. The fraction of apoptotic cells was increased after 3 days incubation with capsaicin (10 μM) paralleled by increased reactive oxygen species production and caspase activity. These effects were even more pronounced, when cells were incubated with MRS1477 (2 μM) either alone or together with CAPS (10 μM). Capsazepine, a TRPV1 blocker, inhibited both the effect of capsaicin and MRS1477. Whole-cell patch clamp recordings revealed that capsaicin-evoked TRPV1-mediated current density levels were increased after 3 days incubation with MRS1477 (2 μM). However, the tumor growth in MCF7 tumor-bearing immunodeficient mice was not significantly decreased after treatment with MRS1477 (10 mg/ kg body weight, i.p., injection twice a week). In conclusion, in view of a putative in vivo treatment with MRS1477 or similar compounds further optimization is required.

Topics: Allosteric Regulation; Animals; Antineoplastic Agents; Apoptosis; Breast Neoplasms; Calcium Signaling; Capsaicin; Cell Survival; Dihydropyridines; Dose-Response Relationship, Drug; Drug Interactions; Humans; MCF-7 Cells; Membrane Potential, Mitochondrial; Mice; Molecular Targeted Therapy; Oxidative Stress; Reactive Oxygen Species; TRPV Cation Channels; Tumor Microenvironment; Xenograft Model Antitumor Assays

The study aimed to investigate the association of long-term use of different antihypertensive agents with incident breast cancer.. A total of 794 ,533 women aged at least 55 years were identified from Taiwan National Health Insurance claims database during 2001-2011. As of 31 December 2011, incident breast cancer patients were included as cases, and 1 : 4 age-matched controls were selected by risk-set sampling scheme. Logistic regression models were applied to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) of breast cancer incidence associated with different durations of use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, β-blockers, and dihydropyridine calcium channel blockers (DHP CCBs). Different restriction rules were applied to reveal the potential effects of confounding by indication.. Among the 9397 incident breast cancer patients and 37 ,588 controls, a significantly elevated risk was found for relatively short-term use of DHP CCBs (<6 years) but not in those observed for more than 6 years. There was no association between either angiotensin-converting enzyme inhibitors/angiotensin receptor blockers or β-blockers use and breast cancer. Although restricting our analyses to those with any prescription of antihypertensive medications in 2001 or those with diagnosis of hypertension, there was no longer a statistically significant association between any use of DHP CCBs and breast cancer (OR: 1.21, 95% CI: 0.88-1.67 for the former, and OR: 1.71, 95% CI: 0.99-2.95 for the latter).. The results demonstrated the potential effect of confounding by indication, and thus, did not suggest any association of the use of antihypertensive medication and breast cancer risk.

Topics: Adrenergic beta-Antagonists; Aged; Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Breast Neoplasms; Calcium Channel Blockers; Case-Control Studies; Dihydropyridines; Female; Humans; Hypertension; Incidence; Logistic Models; Middle Aged; Odds Ratio; Risk Factors; Taiwan

A variety of novel 1,2-dihydropyridines 10-17, thiophenes 18-21 and thiazole 22 having a biologically active sulfone moiety were obtained via the reaction of 2-cyano-N'-[1-(4-(piperidin-1-ylsulfonyl) phenyl) ethylidene] acetohydrazide 3 with a variety of reagents. The structures of the newly synthesized compounds were confirmed by elemental analysis, IR, (1)H NMR, (13)C NMR and mass spectral data. All the newly synthesized compounds were evaluated for their in-vitro anticancer activity against human breast cancer cell line (MCF7). Compounds 15 and 11 with IC(50) values (20.6, 25.5 μM) exhibited better activity than Doxorubicin as a reference drug with IC(50) value (32.02 μM), while compound 14 is nearly as active as Doxorubicin as positive control.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Dihydropyridines; Humans; Inhibitory Concentration 50; Structure-Activity Relationship; Thiazoles; Thiophenes

This paper describes the synthesis of some novel sulfones having biologically active hydrazides (4-9, 22, 23, 26 and 27), hydrazonoyl cyanide (24), 1,2-dihydropyridines (16-21), chromene (28) and benzochromene (29) moieties starting with 1-[4-(piperidin-1-ylsulfonyl)phenyl]-ethanone 1. The structures of the the newly synthesized compounds were confirmed by elemental analysis, IR, 1H NMR and 13C NMR. All the newly synthesized compounds were evaluated for their in vitro anticancer activity against breast cancer cell line (MCF7).

Topics: Antineoplastic Agents; Benzopyrans; Breast Neoplasms; Cell Line, Tumor; Dihydropyridines; Drug Design; Drug Screening Assays, Antitumor; Female; Humans; Hydrazines; Indicators and Reagents; Magnetic Resonance Spectroscopy; Spectrophotometry, Infrared; Structure-Activity Relationship; Sulfones

Modulators of P-glycoprotein (P-gp) are often themselves transported out of cells, thereby limiting their effectiveness. It may be possible to develop more effective modulators of multidrug resistance by designing drugs that irreversibly block the function of P-gp. Therefore, we studied the effect of the mustard derivatives of fluphenazine (FPN) and trans-flupenthixol (FPT) on P-gp function. Both fluphenazine-mustard (FPN-M) and trans-flupenthixol-mustard (FPT-M) possessed alkylating activity, as assayed using 4-(p-nitrobenzyl) pyridine. Multidrug-resistant MCF-7/AdrR cells were incubated with FPN or FPN-M, or FPT or FPT-M for 1 h, washed for varying number of times in phosphate-buffered saline (PBS), then resuspended in medium containing [3H]vinblastine (VBL), and assayed for steady-state accumulation of the drug. Washing had far less of an effect on the ability of FPN-M and FPT-M to increase VBL accumulation compared to their parent compounds. After eight washes in excess PBS, the cells initially exposed to FPN or FPT accumulated only 30% and 50% of the initially accumulated drug, whereas the FPN-M- or FPT-M-treated cells accumulated approximately 75% and 90% of the control, respectively. FPN-M and FPT-M also increased the uptake and decreased the efflux of VBL from MDR cells despite repeated washing. We also examined the effects of these modulators on sensitivity of MDR cells to cytotoxic agents. FPN-M and FPT-M sensitized MCF-7/AdrR cells to VBL and doxorubicin to a greater extent than their parent compounds. These studies point out the potential of "irreversible" P-gp modulators to produce prolonged chemosensitization.

Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Azides; Breast Neoplasms; Dihydropyridines; Dose-Response Relationship, Drug; Doxorubicin; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Female; Flupenthixol; Fluphenazine; Humans; Tumor Cells, Cultured; Vinblastine

The predominant characteristics of multidrug resistant (MDR) cancer cells are broad spectrum resistance to chemotherapeutic agents and a pronounced defect in intracellular accumulation of the drugs, in association with overexpression of the drug efflux pump P-glycoprotein. Protein kinase C (PKC) phosphorylates the linker region of P-glycoprotein. Evidence has been presented that the isozyme PKC-alpha may contribute to the drug resistance phenotype of human breast cancer MCF7-MDR cells, PKC-alpha is markedly overexpressed in MCF7-MDR cells, and artificial overexpression of PKC-alpha in MCF7 constructs that overexpress P-glycoprotein significantly enhances the MDR phenotype of the cells in association with increased P-glycoprotein phosphorylation. Verapamil, cyclosporin A, and a number of other agents that compete with cytotoxic drugs for binding sites on P-glycoprotein can potently reverse MDR, but this is accompanied by severe toxicity in vivo. In this report, we demonstrate that an N-myristoylated peptide that contains a sequence corresponding to the pseudosubstrate region of PKC-alpha (P1) partially reverses multidrug resistance in MCF7-MDR cells by a novel mechanism that involves inhibition of PKC-alpha. P1 and two related PKC inhibitory N-myristoylated peptides restored intracellular accumulation of chemotherapeutic drugs in association with inhibition of the phosphorylation of three PKC-alpha substrates in MCF7-MDR cells: PKC-alpha, Raf-1 kinase, and P-glycoprotein. A fourth N-myristoylated peptide substrate analog of PKC, P7, did not affect drug accumulation in the MCF7-MDR cells and failed to inhibit the phosphorylation of the PKC-alpha substrates. The effects of P1 and verapamil on drug accumulation in MCF7-MDR cells were additive. P1 did not affect P-glycoprotein expression. MCF7-MDR cells were not cross-resistant to P1, which suggest that the peptide was not transported by P-glycoprotein. Furthermore, P1 was distinguished from MDR reversal agents such as verapamil and cyclosporin A by its inability to inhibit [3H]azidopine photoaffinity labeling of P-glycoprotein. P1 actually increased [3H] azidopine photoaffinity labeling of P-glycoprotein in MCF7-MDR cells, providing evidence that the effects of P1 on P-glycoprotein in MCF7-MDR cells are not restricted to inhibition of the phosphorylation of the pump. P1 may provide a basis for developing a new generation of MDR reversal agents that function by a novel mechanism that involves inhibition of PKC

Topics: Affinity Labels; Amino Acid Sequence; ATP Binding Cassette Transporter, Subfamily B, Member 1; Azides; Breast Neoplasms; Dihydropyridines; Drug Resistance, Multiple; Female; Humans; Isoenzymes; Molecular Sequence Data; Myristic Acid; Myristic Acids; Oligopeptides; Phosphorylation; Protein Kinase C; Protein Kinase C-alpha; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-raf; Tumor Cells, Cultured

We have performed isobologram analyses of the ability of tamoxifen (TAM) to alter the response to Adriamycin (ADR) and vinblastine (VBL) in human breast cancer cells. MCF-7 cells express functional receptors for estrogen and progesterone but do not express detectable levels of M(r) 170,000 glycoprotein (gp170). CL 10.3 and MCF-7ADR cells are MCF-7 variants which express gp170. CL 10.3 but not MCF-7ADR cells express functional steroid hormone receptors. Tamoxifen (1-2.5 microM) interacts synergistically with ADR and VBL in CL 10.3 and MCF-7ADR cells. TAM increases the cytotoxicity of VBL and ADR and the intracellular levels of [3H]VBL by approximately 2-3-fold. TAM also prevents the binding of [3H]azidopine to gp170. The ability of TAM to concurrently increase the cytotoxic effects of ADR and VBL, increase VBL accumulation, and inhibit the binding of azidopine to gp170 strongly implies that the synergistic effects of TAM are mediated through its effects on gp170. TAM produces an antagonistic to additive interaction with ADR and VBL in MCF-7 cells, and at high concentrations (5 microM) the synergy apparent in CL 10.3 and MCF-7ADR cells is lost. While TAM clearly has a significant potential for use as a chemosensitizing agent, the design of clinical trials may require careful consideration.

Topics: ATP Binding Cassette Transporter, Subfamily B, Member 1; Azides; Breast Neoplasms; Carrier Proteins; Dihydropyridines; Dose-Response Relationship, Drug; Doxorubicin; Drug Interactions; Drug Resistance; Female; Humans; Membrane Glycoproteins; Phenotype; Tamoxifen; Tumor Cells, Cultured; Vinblastine