The protective effect of metformin against testicular damage in diabetes and prostate cancer model.

Individuals with diabetes have an increased risk of breast, colorectal, pancreatic and prostate cancer. Metformin, an oral biguanide used to treat diabetes, has anti-hyperglycaemic, anti-hyperinsulinemic and antioxidant activities. The effects of metformin on testicular tissue damage in cancer and diabetic + cancer rat models were evaluated histologically, immunohistochemically and biochemically. The diabetic model was produced in Copenhagen rats using a single dose of streptozotocin (65 mg/kg), while prostate cancer was induced through subcutaneous inoculation of 2 × 104 Mat-LyLu cells into the animals. At the end of the experimental period, testicular tissues with a close functional relationship to the prostate were collected. Histological evaluation found moderate to severe damage to testes following the diabetes and cancer process. Histopathological and biochemical impairments were observed in the early stage of prostate cancer, which were increased in the diabetic animals. Metformin administration reversed these injuries and provided substantial protection of the testes. In particular, metformin had protective effects on tissue damage, apoptosis, oxidative stress and antioxidant capacity. This suggests that metformin should be further investigated as a targeted protective drug against prostate cancer-related damage to the testes.

Histological and biochemical investigation of the renoprotective effects of metformin in diabetic and prostate cancer model.

BACKGROUND: Diabetes and cancer have common physiological and biochemical mechanisms. Metformin is the preferred drug of choice for the treatment of diabetes. Prostate cancer can be modeled in by injection of MAT-Lylu cells. A model of diabetes in rats is induced by streptozotocin injection. In the current study, we explored the mechanisms by which diabetes accelerates cancer, and evaluated the effects of metformin to know whether it has any impact against the damage caused by cancer and diabetic + cancer via histopathological and biochemical parameters of kidney tissue. METHODS: The experiment was carried out in rats. Groups 1-Control, 2- Diabetic, 3-Cancer, 4-Diabetic + cancer, 5-Diabetic + cancer + metformin, 6-Cancer + metformin. Metformin treatment was applied by gavage every day. The research ended on the 14th day. The collected kidney tissue sections were stained with Hematoxylin-Eosin. RESULTS: Histological evaluation showed moderate to severe damage to the kidney tissue following diabetic and cancer processess. In diabetic, cancer and diabetic + cancer groups, reduced glutathione levels, total antioxidant status, sodium/potassium-ATPase and paraoxonase1 activities were found to be significantly abated. While advanced oxidized protein products, lipid peroxidation, nitric oxide, tumor necrosis factor-alpha, reactive oxygen species levels, total oxidant status, catalase, superoxide dismutase, glutathione-related antioxidant enzymes, myeloperoxidase, and arginase activities were significantly raised. The administration of metformin reversed these defects. The outcome of the reveals that histopathological and biochemical damage in cancer and diabetes + cancer groups decreased in the groups that received metformin. CONCLUSION: In conclusion, metformin treatment can be considered an adjuvant candidate for kidney tissue in diabetes, prostate cancer and cancer therapy related damage.

Brain Boron Level, DNA Content, and Myeloperoxidase Activity of Metformin-Treated Rats in Diabetes and Prostate Cancer Model.

In this study, the effect of metformin on boron levels and oxidative brain damage in rats due to diabetes and prostate cancer was investigated for the first time. Myeloperoxidase (MPO) activity and the amount of DNA were investigated as tissue oxidative and toxic damage parameters. In Copenhagen rats, Dunning prostate cancer was induced using high metastatic MAT-Lylu cells and diabetes was induced by single dose of streptozotocin (STZ) injection. Metformin was administered for 14 days after diabetes and prostate cancer induced. The rats were divided into six groups as follows: control group, diabetic group (D), cancer group (C), diabetic + cancer (DC) group, cancer + metformin (CM) group, diabetic + cancer + metformin (DCM) group. At the end of the experiment, brains were removed. Significant decrease of brain boron levels and significant elevation of MPO activity and DNA levels were observed in D, C, and DC groups as compared to control group. The effect of diabetes induction on the brain boron levels was much more than prostate cancer induction. The administration of metformin with CM and DCM obviously declined MPO activity and increased brain boron levels almost near to control group level. In conclusion, this study shows that the protective effect of metformin against brain damage in STZ-induced diabetic rats with Dunning prostate cancer may also be related to increased boron levels. The boron levels may be a novel indicator of reduced toxic and oxidative stress. Furthermore, the distribution and mechanism of action of boron should be clarified.

Anti-metastatic effect of ranolazine in an in vivo rat model of prostate cancer, and expression of voltage-gated sodium channel protein in human prostate.

BACKGROUND: Voltage-gated Na+ channels (VGSCs) are functionally upregulated in rat and human prostate cancer (PCa) where channel activity promotes cellular invasiveness in vitro and metastasis in vivo. Ranolazine is a clinically used VGSC inhibitor/anti-anginal drug, which has been shown previously to inhibit breast cancer metastasis in vivo. METHODS: Using the Dunning model of rat PCa, the effect of ranolazine applied systemically (by gavage) was tested on the development of primary tumours and metastases following subcutaneous inoculation of Mat-LyLu cells into Copenhagen rats. In addition, human prostate tissue microarrays were used to determine VGSC protein expression in cancerous versus non-cancerous tissue. Several public databases were searched to compare Nav1.7/ SCN9A expression levels in 'normal' vs. PCa tissues. RESULTS: Ranolazine (2.5 and 5 µM) decreased the number of lung metastases by up to 63%. In contrast, primary tumourigenesis was not affected. Ranolazine also reduced the percentage of cells in the metastases expressing Nav1.7, the main VGSC subtype expressed in PCa, but the expression level was higher. In prostate tissue microarrays, VGSC protein expression was significantly higher in cancerous versus non-cancerous tissue. There was no correlation between the VGSC expression and either prostate-specific antigen or Gleason score. In public databases, little information could be found on Nav1.7 protein expression in PCa. In addition, the database information on Nav1.7 mRNA (SCN9A) expression levels did not correlate with previously reported upregulation in PCa cells and tissues. CONCLUSIONS: The main conclusions were (i) ranolazine inhibited metastasis and (ii) it was a subpopulation of cells with particularly high levels of Nav1.7 protein that reached the metastatic sites. These data extend earlier studies and suggest that Nav1.7 expression could serve as a functional biomarker of metastatic PCa and that VGSC blockers may be useful as anti-metastatic agents.

Gabapentin, an Analgesic Used Against Cancer-Associated Neuropathic Pain: Effects on Prostate Cancer Progression in an In Vivo Rat Model.

A major problem associated with clinical management of cancer is controlling the accompanying pain, and various analgesics are in common use for this purpose. Recent evidence suggests that some of the targets of analgesics, such as ion channels and receptors, may also be involved in the cancer process, thereby raising the possibility that such use of some analgesics may impact upon cancer itself. The main aim of this study was to determine whether gabapentin, a common adjuvant analgesic in current use against cancer-associated neuropathic pain, would affect tumour development and progression in vivo. The Dunning rat model of prostate cancer was used. Strongly metastatic Mat-LyLu cells were implanted subcutaneously into syngeneic Copenhagen rats which were then treated every other day with 4.6-16.8 µg/kg gabapentin by gavage. Primary tumourigenesis was monitored daily. Lung metastases were counted and measured after killing the rats 21 days later. Gabapentin had no effect on primary tumourigenesis but produced dose-dependent effects on lung metastasis. Whilst 4.6 µg/kg had no effect, 9.1 µg/kg gabapentin decreased the number of lung metastases significantly by 64%. In contrast, 16.8 µg/kg gabapentin promoted metastasis significantly by 112% and showed a strong tendency to shorten mean survival time. It is concluded that gabapentin prescribed to cancer patients against pain could impact upon the cancer process itself.

Inhibitory effects of dunning rat prostate tumor fluid on proliferation of the metastatic MAT-LyLu cell line.

Tumor fluid accumulation occurs in both human cancer and experimental tumor models. Solid tumors show a tendency to tumor fluid accumulation because of their anatomical and physiological features and this may be influenced by molecular factors. Fluid accumulation in the peri-tumor area also occurs in the Dunning model of rat prostate cancer as the tumor grows. In this study, the effects of tumor fluids that were obtained from Dunning prostate tumor-bearing Copenhagen rats on the strongly metastatic MAT-LyLu cell line were investigatedby examining the cell's migration and tumor fluid's toxicity and the kinetic parameters such as cell proliferation, mitotic index, and labelling index. In this research, tumor fluids were obtained from rats injected with 25105 MAT- LyLu cells and treated with saline solution, and 200 nM tetrodotoxin (TTX), highly specific sodium channel blocker was used. Sterilized tumor fluids were added to medium of MAT-LyLu cells with the proportion of 20% in vitro. Consequently, it was demonstrated that Dunning rat prostate tumor fluid significantly inhibited proliferation (up to 50%), mitotic index, and labeling index of MAT-LyLu cells (up to 75%) (p<0.05) but stimulated the motility of the cells in vitro.