RESUMEN
Type 2 diabetes is associated with increased fracture risk and delayed fracture healing; the underlying mechanism, however, remains poorly understood. We systematically investigated skeletal pathology in leptin receptor-deficient diabetic mice on a C57BLKS background (db). Compared with wild type (wt), db mice displayed reduced peak bone mass and age-related trabecular and cortical bone loss. Poor skeletal outcome in db mice contributed high-glucose- and nonesterified fatty acid-induced osteoblast apoptosis that was associated with peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) downregulation and upregulation of skeletal muscle atrogenes in osteoblasts. Osteoblast depletion of the atrogene muscle ring finger protein-1 (MuRF1) protected against gluco- and lipotoxicity-induced apoptosis. Osteoblast-specific PGC-1α upregulation by 6-C-ß-d-glucopyranosyl-(2S,3S)-(+)-5,7,3',4'-tetrahydroxydihydroflavonol (GTDF), an adiponectin receptor 1 (AdipoR1) agonist, as well as metformin in db mice that lacked AdipoR1 expression in muscle but not bone restored osteopenia to wt levels without improving diabetes. Both GTDF and metformin protected against gluco- and lipotoxicity-induced osteoblast apoptosis, and depletion of PGC-1α abolished this protection. Although AdipoR1 but not AdipoR2 depletion abolished protection by GTDF, metformin action was not blocked by AdipoR depletion. We conclude that PGC-1α upregulation in osteoblasts could reverse type 2 diabetes-associated deterioration in skeletal health.
Asunto(s)
Enfermedades Óseas Metabólicas/etiología , Diabetes Mellitus Tipo 2/complicaciones , Proteínas Musculares/genética , Músculo Esquelético/metabolismo , Osteoblastos/fisiología , Receptores de Adiponectina/fisiología , Factores de Transcripción/fisiología , Animales , Densidad Ósea , Enfermedades Óseas Metabólicas/prevención & control , Resistencia a la Insulina , Ratones , Ratones Endogámicos C57BL , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma , Receptores de Adiponectina/agonistasRESUMEN
Breast cancer is one of the most common malignancies among women, representing nearly 30% of newly diagnosed cancers every year. Till date, various therapeutic interventions, including surgery, chemotherapy, hormonal therapy, and radiotherapy are available and are known to cause a significant decline in the overall mortality rate. However, therapeutic resistance, recurrence and lack of treatment in metastasis are the major challenges that need to be addressed. Increasing evidence suggests the presence of cancer stem cells (CSCs) in heterogeneous population of breast tumors capable of selfrenewal and differentiation and is considered to be responsible for drug resistance and recurrence. Therefore, compound that can target both differentiated cancer cells, as well as CSCs, may provide a better treatment strategy. Due to safe nature of dietary agents and health products, investigators are introducing them into clinical trials in place of chemotherapeutic agents.This current review focuses on phytochemicals, mainly flavonoids that are in use for breast cancer therapy in preclinical phase. As phytochemicals have several advantages in breast cancer and cancer stem cells, new synthetic series for breast cancer therapy from analogues of most potent natural molecule can be developed via rational drug design approach.
Asunto(s)
Antineoplásicos Fitogénicos/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Fitoquímicos/uso terapéutico , Animales , Antineoplásicos Fitogénicos/química , Antineoplásicos Fitogénicos/metabolismo , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Femenino , Predicción , Humanos , Fitoquímicos/química , Fitoquímicos/metabolismoRESUMEN
Employing a rational design of thioaryl naphthylmethanone oxime ether analogs containing functional properties of various anticancer drugs, a series of compounds were identified that displayed potent cytotoxicity toward various cancer cells, out of which 4-(methylthio)phenyl)(naphthalen-1-yl)methanone O-2-(diethylamino)ethyl oxime (MND) exhibited the best safety profile. MND induced apoptosis, inhibited migration and invasion, strongly inhibited cancer stem cell population on a par with salinomycin, and demonstrated orally potent tumor regression in mouse MCF-7 xenografts. Mechanistic studies revealed that MND strongly abrogated EGF-induced proliferation, migration, and tyrosine kinase (TK) signaling in breast cancer cells. However, MND failed to directly inhibit EGFR or other related receptor TKs in a cell-free system. Systematic investigation of a putative target upstream of EGFR revealed that the biological effects of MND could be abrogated by pertussis toxin. Together, MND represents a new nonquinazoline potential drug candidate having promising antiproliferative activity with good safety index.
Asunto(s)
Antineoplásicos/síntesis química , Compuestos de Bencidrilo/síntesis química , Oximas/síntesis química , Animales , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Compuestos de Bencidrilo/farmacología , Ciclo Celular/efectos de los fármacos , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Receptores ErbB/fisiología , Humanos , Ratones , Invasividad Neoplásica , Células Madre Neoplásicas/efectos de los fármacos , Oximas/farmacología , Transducción de Señal/fisiología , Relación Estructura-ActividadRESUMEN
Adiponectin is an adipocytokine that signals through plasma membrane-bound adiponectin receptors 1 and 2 (AdipoR1 and -2). Plasma adiponectin depletion is associated with type 2 diabetes, obesity, and cardiovascular diseases. Adiponectin therapy, however, is yet unavailable owing to its large size, complex multimerization, and functional differences of the multimers. We report discovery and characterization of 6-C-ß-D-glucopyranosyl-(2S,3S)-(+)-5,7,3',4'-tetrahydroxydihydroflavonol (GTDF) as an orally active adiponectin mimetic. GTDF interacted with both AdipoRs, with a preference for AdipoR1. It induced adiponectin-associated signaling and enhanced glucose uptake and fatty acid oxidation in vitro, which were augmented or abolished by AdipoR1 overexpression or silencing, respectively. GTDF improved metabolic health, characterized by elevated glucose clearance, ß-cell survival, reduced steatohepatitis, browning of white adipose tissue, and improved lipid profile in an AdipoR1-expressing but not an AdipoR1-depleted strain of diabetic mice. The discovery of GTDF as an adiponectin mimetic provides a promising therapeutic tool for the treatment of metabolic diseases.
Asunto(s)
Adiponectina/sangre , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Quercetina/análogos & derivados , Quercetina/uso terapéutico , Receptores de Adiponectina/metabolismo , Animales , Diabetes Mellitus Tipo 2/metabolismo , Modelos Animales de Enfermedad , Ácidos Grasos/metabolismo , Glucosa/metabolismo , Insulina/metabolismo , Resistencia a la Insulina , Metabolismo de los Lípidos/efectos de los fármacos , Ratones , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/metabolismo , Obesidad/metabolismo , Quercetina/farmacología , Transducción de Señal/efectos de los fármacosRESUMEN
In order to enhance the bioavailability of curcumin its conjugates with piperic acid and glycine were synthesized by esterifying the 4 and 4' phenolic hydroxyls, the sites of metabolic conjugation. Antiproliferative and apoptotic efficacy of synthesized conjugates was investigated in MCF-7 and MDA-MB-231 cell lines. IC50 values of di-O-glycinoyl (CDG) and di-O-piperoyl (CDP) esters of curcumin were found to be comparable with that of curcumin. Both conjugates induced chromatin condensation fragmentation and apoptotic body formation. CDP exposure to MCF-7 cells induced apoptosis initiating loss of mitochondrial membrane potential (Δψm) followed by inhibition of translocation of transcription factor NF-kB and release of Cytochrome-C. Reactive oxygen species (ROS) production was evaluated by fluorescent activated cell sorter. Change in ratio of Bcl2/ Bclxl was observed, suggesting permeablization of mitochondrial membrane leading to the release of AIF, Smac and other apoptogenic molecules. DNA fragmentation as a hallmark for apoptosis was monitored by TUNEL as well as agrose gel electrophoresis. Thus, it was proven that conjugation does not affect the therapeutic potential of parent molecule in vitro, while these could work in vivo as prodrugs with enhanced pharmacokinetic profile. Pharmacokinetics of these molecules under in vivo conditions is a further scope of this study.
Asunto(s)
Apoptosis/efectos de los fármacos , Curcumina/farmacología , Mitocondrias/efectos de los fármacos , Línea Celular Tumoral , Citocromos c/metabolismo , Fragmentación del ADN/efectos de los fármacos , Humanos , Células MCF-7 , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Mitocondrias/metabolismo , FN-kappa B/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Especies Reactivas de Oxígeno/metabolismoRESUMEN
The question whether chemotherapy-induced autophagy is causative to the demise of the cells or a part of the survival mechanism activated during cellular distress is unclear. Others and we have previously demonstrated apoptosis-inducing capacity of N-(4-hydroxyphenyl)retinamide (4-HPR) in malignant glioma cells. We provide evidences of 4-HPR-induced autophagy at a lower concentration (5 microM). Suboptimal dose of 4-HPR treatment of malignant glioma cell lines increased G(2)/M arrest, whereas cell accumulated in S phase at a higher concentration. 4-HPR-induced autophagy was associated with acidic vacuole [acidic vesicular organelle (AVO)] formation and recruitment of microtubule-associated protein light chain 3 (LC3). At a higher concentration of 10 microM of 4-HPR, glioma cells undergoing apoptosis manifested autophagic features indicated by autophagosome formation, AVO development and LC3 localization. Autophagy inhibition at an early stage by 3-methyl adenine inhibited the AVO formation and LC3 localization with an enhancement in cell death. Bafilomycin A1, a specific inhibitor of vacuolar type Hthorn-ATPase also prevented AVO formation without effecting LC-3 localization pattern and also enhanced the extent of 4-HPR-induced cell death. 4-HPR activated c-jun and P38(MAPK) at both 5 and 10 microM concentrations, whereas increased activation of extracellular signal-regulated kinase 1/2 and NF-kappaB was seen only at lower dose. Inhibiting phosphoinositide 3-kinase and mitogen-activated protein kinases pathways modulated 4-HPR-induced cell death. This is the first report that provides evidences that besides apoptosis induction 4-HPR can also induce autophagy. These results indicate that 4-HPR-induced autophagy in glioma cell may provide survival advantage and inhibition of autophagy may enhance the cytotoxicity to 4-HPR.
Asunto(s)
Autofagia/efectos de los fármacos , Neoplasias Encefálicas/patología , Muerte Celular/efectos de los fármacos , Fenretinida/antagonistas & inhibidores , Glioma/patología , Línea Celular Tumoral , Relación Dosis-Respuesta a Droga , Fenretinida/farmacología , Citometría de Flujo , Humanos , Inmunohistoquímica , Microscopía Electrónica de Transmisión , Proteínas Quinasas/metabolismoRESUMEN
N-(4-hydroxyphenyl)retinamide (4-HPR), a synthetic retinoid is under clinical evaluation as a therapeutic agent in a variety of cancers. Its mechanism(s) of action involves multiple overlapping pathways that still remain unclear. In glioma cells its mechanism of action is not well elucidated. Here, we show that 4-HPR and not all-trans retinoic acid and 9-cis retinoic acid effectively induce apoptosis in glioma cells. 4-HPR-induced apoptosis is associated with hydroperoxide production and loss of mitochondrial membrane potential (Delta Psi(m)). Ultrastructural changes further indicate 4-HPR-induced mitochondrial swelling, endoplasmic reticulum (ER) dilation as well as close proximity of mitochondria and ER. As suggested by dilated ER, 4-HPR treatment increased the free cytosolic Ca(2+) as well as mitochondrial Ca(2+). Chelation of extracellular Ca(2+) by EGTA did not prevent Ca(2+) elevation, thus suggesting involvement of intracellular calcium stores in the release. Buffering of intracellular calcium by BAPTA-AM did not prevent 4-HPR-induced apoptosis; however, blocking the release of Ca(2+) from ER by heparin inhibited apoptosis, indicating the role of depletion of Ca(2+) from ER stores in apoptosis. 4-HPR treatment also resulted in an increase in Bax levels along with its translocation to mitochondria that promote mitochondrial membrane permeabilization. 4-HPR-induced apoptosis was further associated with the release of cytochrome c and apoptosis-inducing factor (AIF) from mitochondria to cytosol and nucleus, respectively, along with caspase-3 and caspase-7 activation. However, AIF nuclear translocation, peripheral chromatin condensation and apoptosis were not completely prevented by general caspase inhibitors, thus suggesting involvement of a caspase-dependent and caspase-independent pathway in 4-HPR-induced apoptosis. Taken together, these results suggest the role of mitochondrial-mediated pathway and ER stress as a key event in 4-HPR-induced apoptosis in glioma cells.