Metformin promotes apoptosis in primary breast cancer cells by downregulation of cyclin D1 and upregulation of P53 through an AMPK-alpha independent mechanism

Background/aim: In the present study we aimed to figure out the effect of metformin on the expression of AMPK-alpha, cyclin D1, and Tp53, and apoptosis in primary breast cancer cells (PBCCs). Materials and methods: PBCCs were treated with two doses of metformin (0 mM, 25 mM). Proliferation was determined by BrdU as- say. Real-time PCR was used to assess AMPK-alpha, cyclin D1, and Tp53 gene expressions; apoptotic indexes of PBCCs were analyzed using flow-cytometry. Results: Twenty-four­hour incubation with 25 mM metformin reduced the proliferation of PBCCs. AMPK-alpha gene expression in PBCCs was not affected by 25 mM metformin treatment compared with the control group. PBCCs treated with 25 mM metformin had lower cyclin D1 expression compared with nontreated cells; however, the difference was not statistically significant. Twenty-five mil- limolar dose of metformin increased p53 expression significantly compared with the nontreated group. The high concentration of met- formin elevated the number of annexin V-positive apoptotic cells, and the increase in the apoptotic index was statistically significant. Conclusion: Metformin can modulate cyclin D1 and p53 expression through AMPK-alpha-independent mechanism in breast cancer cells, leading to cell proliferation inhibition and apoptosis induction.

The effects of cephalexin on fracture healing in a rat femur fracture model.

OBJECTIVES: The aim of this study was to examine the effects of cephalexin on the fracture union histomorphometrically, radiologically, biomechanically, immunohistochemically, and histopathologically in a rat femur fracture model and to evaluate the effects of the antibiotics to be used in the prophylaxis of fracture infection on the union of the fracture. MATERIALS AND METHODS: A total of 48 male Wistar rats were divided into four groups as two-week control (C2) and cephalexin (CEP2) and four-week control (C4) and cephalexin (CEP4). After establishment of standard fracture model on right femurs, 60 mg/kg/day of cephalexin was applied to CEP2 and CEP4 by oral gavage. Radiological, biomechanical, histopathological, immunohistochemical, and histomorphometric examinations were performed on amputated femurs. RESULTS: Callus volume of CEP4 group significantly increased compared to CEP2 group (p=0.005), while no significant difference was found in the bone mineral density and callus/bone volume among the groups (p>0.05). There was no significant difference in flexural strength between the C4 and CEP4 groups (p=0.093). Histological healing scores increased from Week 2 to Week 4 (p=0.002) and inflammation scores decreased in both control and cephalexin groups (p=0.010 and p=0.008); however, no significant difference was found in healing and inflammation scores (p>0.05). The CD34+ immunoreactivity in the CEP2 group was significantly higher than the C2 group (p=0.029). Collagen type III level was significantly lower in the CEP2 and CEP4 groups compared to the corresponding control groups (p=0.008 and p=0.016, respectively). CONCLUSION: Cephalexin did not exert any radiological, histopathological, histomorphometric, biomechanical, and immunohistochemical adverse effects on the femoral fracture healing model in rats; however, it showed positive effects on CD34 and Collagen type III levels. Based on these findings, antibiotherapy with cephalexin may be considered as a safe treatment for fracture union.

The effects of thymoquinone on steroid-induced femoral head osteonecrosis: An experimental study in rats.

OBJECTIVES: In this study, we aimed to evaluate the antioxidant, anti-apoptotic, osteoblastic and hypolipidemic effects of thymoquinone (TQ) treatment on the steroid-induced osteonecrosis of femoral head (ONFH) model in rats. MATERIALS AND METHODS: A total of 24 rats were randomly divided into four groups: the control group administered saline; the TQ group administered 10 mg/kg/day TQ orally; lipopolysaccharide/methylprednisolone (LPS/MPS) group administered 20 µg/kg intraperitoneally LPS and 40 mg/kg intramuscularly MPS to establish ONFH model; and the LPS/ MPS+TQ group administered both LPS/MPS and, then, TQ once daily for four weeks. All rats were sacrificed after intracardiac blood collection and their right femurs were removed. RESULTS: Micro-computed tomography showed a higher bone mineral density and lower porosity, Tr. Sp and Tr. Sep data were detected in the LPS/MPS+TQ group. In histopathology, osteonecrosis increased significantly in the LPS/MPS group and osteonecrosis decreased in the LPS/MPS+TQ group compared to the LPS/MPS group (p=0.0077). Histomorphometric examination revealed that the percentage of BV/TV in the LPS/MPS group was significantly lower compared to control and other groups (p<0.01 and p<0.05, respectively), while it reached normal rates in the LPS/MPS+TQ group. Immunohistochemically, antioxidant, anti-apoptotic, and angiogenesis indicators (8-hydroxy-20- deoxyguanosine [8-OHdG], malondialdehyde [MDA], B-cell lymphoma [Bcl-2], caspase-3, vascular endothelial growth factor [VEGF]) were significantly improved in tissue and serum with TQ. Furthermore, TQ significantly reduced low- and high-density lipoprotein cholesterol ratio and carboxy-terminal type 1 collagen crosslink (CTX) in serum. CONCLUSION: Vascular and hematopoietic cell damages that occur due to steroid-induced deoxyribonucleic acid (DNA) oxidative and lipid peroxidative damages in an ONFH model can be successfully ameliorated by TQ administration. This antioxidant and anti-apoptotic effects of TQ may be a promising treatment option for early stage of osteonecrosis.

Effects of different vardenafil doses on bone healing in a rat fracture model.

OBJECTIVES: We aimed to investigate the radiological, biomechanical, histopathological, histomorphometric, and immunohistochemical effects of different doses of vardenafil on fracture healing. MATERIALS AND METHODS: Fifty-one rats were divided into three groups. Group V5 was given 5 mg/kg/day of vardenafil; Group V10 was given 10 mg/kg/day of vardenafil; and the control group was given the same volume of saline. Six rats from each group were sacrificed on Day 14 (early period) and the remaining rats were sacrificed on Day 42 (late period). Callus/femoral volume and bone mineral density were measured using micro-computed tomography. Five femurs from each group in the late period were examined by biomechanical tests. In addition to the histopathological and histomorphometric evaluations, immunohistochemical analyses were performed to examine the levels of inducible nitric oxide synthase (iNOS), transforming growth factor-3 (TGF-ß3), and nuclear factor kappa B (NF-κB) proteins. RESULTS: Both doses of vardenafil increased primary bone volume and maximal bone fracture strength in late period, compared to the control group (p<0.05). Histological healing scores of vardenafil groups were significantly higher in early period (p<0.001). While cartilaginous callus/total callus ratio in early period was higher, callus diameter/femoral diameter ratio in late period was lower in vardenafil groups (p<0.01). The NF-κB immunopositivity in V10 group decreased in early period, compared to control group (p<0.001). The TGF-ß3 and iNOS immunopositivity increased in both V5 and V10 groups, compared to the control group in early period, but returned to normal in late period. CONCLUSION: During the first period of fracture healing process in which vasodilation is mostly required with increasing inflammation, vardenafil has ameliorating effects on the bone union and supports fracture healing.

Anti-cancer effect of metformin on the metastasis and invasion of primary breast cancer cells through mediating NF-kB activity.

Current evidence strongly suggests that aberrant activation of the nuclear factor kappa B (NF-kB) signaling cascade is connected to carcinogenesis. The matrix metalloproteinases (MMP) which are also the key agents for tumor metastasis may be potent candidates for tumor diagnosis in clinics. In this in vitro study, we hypothesized that metformin with an effective dose can inhibit tumor cell proliferation and metastasis by modulating the expressions of MMP-2 and -9 and interfering with NF-kB signaling in primary breast cancer cells (PBCCs). 300 000 cells per ml were obtained from biopsies of breast tumors from five human donors. The cell viability and proliferation were tested. Immunocytochemistry was performed for MMP-2, MMP-9, and NF-kB, and enzyme-linked immunosorbent assay for NF-kB activity, quantitative real-time PCR for RELA/p65, IkBα, MMP-2, and MMP-9. Three different doses of metformin (5, 10, and 25 mM) (Met) reduced the viability and proliferation of PBCCs in a dose-dependent manner, maximum inhibition was observed at 25 mM Met. The expression of RELA/p65 was not affected by 25 mM Met. Nuclear immunoreactivity and activity of NF-kB reduced while cytoplasmic NF-kB (p65) elevated by 25 mM Met compared to non-treatment (P <  0.05). The expression and immunoreactivity of MMP-9 but not MMP-2 were decreased by 25 mM Met treatment, compared with the non-treatment (P <  0.05). Metformin may have an essential antitumor role in the invasion and metastasis pathways of PBCCs by downregulating the MMP-9 expression blocking both the activity and nuclear translocation of NF-kB.

The protective effects of metformin in an in vitro model of aging 3T3 fibroblast under the high glucose conditions.

Metformin is the most widely used anti-diabetic drug in the world. It reduces advanced glycation end product (AGEs)-induced ROS generation in high glucose condition. Protein glycation contributes to skin aging as it deteriorates the existing collagen by crosslinking. The progressive increase of AGE during aging not only causes oxidative damage to cellular macromolecules but also modulates the activation of transcription factors nuclear factor kappa-B(NF-kB). However, it is still unclear whether metformin can change collagen production and NF-kB activity induced by high glucose conditions in 3T3 fibroblast. The effects of metformin on proliferation, apoptosis, and collagen levels and NF-kB activity of in vitro cell aging model of 3T3 fibroblast cells in high glucose conditions. At first, we investigated the effects of 50 mM high glucose concentration, with or without metformin, on 3T3 fibroblast proliferation, by BrdU immunostaining for cell proliferation. Apoptotic levels were analyzed by flow cytometric assay. NF-kB(p65) activity was measured by transcription factor assay kit and collagen I and III levels by Collagen Estimation Assay through ELISA. We observed that metformin exposure leads to decreased apoptosis levels and increased proliferation of 3T3 fibroblast in high glucose media. We also determined that metformin exposure leads to increased production of collagen I-III and decreased activation of NF-kB(p65) activity. The data are consistent with the observation that metformin has a protective effect in this in vitro model of aging 3T3 fibroblasts under high glucose conditions inducing cell proliferation, collagen I and III production, protection from apoptosis, and reducing NF-kB(p65) activity.

The relationship between glomerular function and podocyte structure of pre-proteinuria and acute nephrosis in puromycin aminonucleoside-induced rat models: a comparative electron microscopic study.

Puromycin aminonucleoside (PA) has been generally utilized as model of podocyte injury followed by massive proteinuria, severe damage on endocytotic activity of epithelial cells and postmodification of endocytosed compounds. However, total PA nephrosis (PAN) mechanism cannot be understood. We aimed to study glomerular function, foot process degeneration and transport pathways of podocytes in pre-proteinuria and acute PAN rats. Eighteen male Wistar albino rats were divided into three groups: control, pre-proteinuria and acute nephrosis groups (n=6). PA was injected into pre-proteinuria group for three times and acute group for nine times. Proteinuria levels in urine, creatinine and albumin levels in blood were detected 24 hours after PA injections. Renal cortex samples were prepared for transmission electron microscopy. Proteinuria levels in acute group significantly elevated, whereas creatinine clearance, serum albumin levels and urine volumes diminished compared to control and pre-proteinuria groups. In pre-proteinuria group, hypertrophy and structurally rich cytoplasm were detected only within podocytes. Acute group had various protein absorption granules secreted from podocyte cytoplasm to the urinary space through exocytosis after lysosomal digestion; but not observed in pre-proteinuria group. The number of slit pores in pre-proteinuria group decreased, particularly related to fusion of foot processes, subsequently leading to proteinuria. We concluded that foot process fusion begins prior to development of proteinuria although their serum albumin and creatinine clearance levels do not differ significantly. Additionally, we suggested that in acute PAN, first affected glomerular cells could be podocytes and there could be a correlation between glomerular function and number of slit pores.

Anti-inflammatory and ultrastructural effects of Turkish propolis in a rat model of endotoxin-induced uveitis.

INTRODUCTION: Experimental animal models of acute uveitis, an inflammatory eye disease, can be established via endotoxin-induced inflammation. Propolis, a natural substance collected by honeybees from buds and tree exudates, has antioxidant, antibacterial, antiviral, and anti-inflammatory effects. We investigated the effects of propolis, obtained from the Sakarya province of Turkey, on endotoxin-induced uveitis using immunohistochemical, ultrastructural, and biochemical approaches. MATERIAL AND METHODS: Male Wistar albino rats (n = 6/group) received intraperitoneal (ip) lipopolysaccharide (LPS) endotoxin (150 µg/kg) followed by aqueous extract of propolis (50 mg/kg ip) or vehicle; two additional groups received either saline (control) or propolis only. After 24 h, aqueous humor (AH) was collected from both eyes of each animal for analysis of tumor necrosis factor-α (TNF-α) and hypoxia-inducible factor-1α (HIF-1α). Right eyeballs were paraffin-embedded for immunohistochemical staining of nuclear factor κB (NF-κB)/p65 and left eyeballs were araldite-embedded for ultrastructural analysis. RESULTS: Treatment of LPS-induced uveitis with propolis significantly reduced ciliary body NF-κB/p65 immunoreactivity and AH levels of HIF-1α and TNF-α. Ultrastructural analysis showed fewer vacuoles and reduced mitochondrial degeneration in the retinal pigment epithelium, as compared to the uveitis group. The intercellular spaces of the inner nuclear layer and outer limiting membrane were comparable with those of the control group; no polymorphonuclear cells or stasis was observed in intravascular or extravascular spaces. CONCLUSIONS: This is the first report demonstrating an anti-inflammatory effect of Turkish propolis in a rat model of LPS-induced acute uveitis, suggesting a therapeutic potential of propolis for the treatment of inflammatory ophthalmic diseases.

The protective effects of metformin in an in vitro model of aging 3T3 fibroblast under the high glucose conditions

Metformin is the most widely used anti-diabetic drug in the world. It reduces advanced glycation end product (AGEs)-induced ROS generation in high glucose condition. Protein glycation contributes to skin aging as it deteriorates the existing collagen by crosslinking. The progressive increase of AGE during aging not only causes oxidative damage to cellular macromolecules but also modulates the activation of transcription factors nuclear factor kappa-B(NF-kB). However, it is still unclear whether metformin can change collagen production and NF-kB activity induced by high glucose conditions in 3T3 fibroblast. The effects of metformin on proliferation, apoptosis, and collagen levels and NF-kB activity of in vitro cell aging model of 3T3 fibroblast cells in high glucose conditions. At first, we investigated the effects of 50 mM high glucose concentration, with or without metformin, on 3T3 fibroblast proliferation, by BrdU immunostaining for cell proliferation. Apoptotic levels were analyzed by flow cytometric assay. NF-kB(p65) activity was measured by transcription factor assay kit and collagen I and III levels by Collagen Estimation Assay through ELISA. We observed that metformin exposure leads to decreased apoptosis levels and increased proliferation of 3T3 fibroblast in high glucose media. We also determined that metformin exposure leads to increased production of collagen I-III and decreased activation of NF-kB(p65) activity. The data are consistent with the observation that metformin has a protective effect in this in vitro model of aging 3T3 fibroblasts under high glucose conditions inducing cell proliferation, collagen I and III production, protection from apoptosis, and reducing NF-kB(p65) activity