Diabetes is a risk factor for breast cancer development and is associated with poor prognosis for breast cancer patients. However, the molecular and biochemical mechanisms underlying the association between diabetes and breast cancer have not been fully elucidated. Here, we investigated estradiol response in MCF-7 breast cancer cells with or without chronic exposure to insulin. We found that insulin priming is necessary and specific for estradiol-induced cancer cell growth, and induces anaplerotic shunting of glucose into macromolecule biosynthesis in the estradiol treated cells. Treatment with ERK or Akt specific inhibitors, U0126 or LY294002, respectively, suppressed estradiol-induced growth. Interestingly, molecular analysis revealed that estradiol treatment markedly increases expression of cyclin A and B, and decreases p21 and p27 in the insulin-primed cells. In addition, estradiol treatment activated metabolic genes in pentose phosphate (PPP) and serine biosynthesis pathways in the insulin-primed cells while insulin priming decreased metabolic gene expression associated with glucose catabolism in the breast cancer cells. Finally, we found that anti-diabetic drug metformin and AMPK ligand AICAR, but not thiazolidinediones (TZDs), specifically suppress the estradiol-induced cellular growth in the insulin-primed cells. These findings suggest that estrogen receptor (ER) activation under chronic hyperinsulinemic condition increases breast cancer growth through the modulation of cell cycle and apoptotic factors and nutrient metabolism, and further provide a mechanistic evidence for the clinical benefit of metformin use for ER-positive breast cancer patients with diabetes.
Lung cancer is a major cause of cancer-related death worldwide. It is believed that obesity-related malignancies such as breast, endometrial, colorectal, and kidney carcinomas have lower plasma level and/ or tissue expression of adiponectin receptors. However, the association between adiponectin receptors and lung cancer, a non obesity-related malignancy, is still unknown. We evaluated the tissue expression of adiponectin receptor (AdipoR) 1 and AdipoR2 in 83 cases of non-small cell lung carcinoma (NSCLC) and matched non-neoplastic lung tissues by immunohistochemistry and real-time polymerase chain reaction (PCR). Clinicopathological data, including smoking history, smoker's bronchiolitis, emphysema, lymph node metastasis, and T-stage were collected and evaluated. Expression of immunohistochemically stained AdipoR1 and AdipoR2 was observed in all samples of non-neoplastic lung tissues. Both receptors showed higher mRNA expression in non-neoplastic than neoplastic tissues ( p < 0.05). In NSCLC tissues, AdipoR1 immunohistochemical expression was not observed in most of patients with squamous cell carcinoma and current smoking history (31/42, p = 0.04 and 25/29, p = 0.003, respectively). Additionally, AdipoR1 mRNA expression was significantly lower in patients with lymph node metastasis ( p = 0.05). Meanwhile, AdipoR2 immunohistochemical stain expression was inversely correlated with T-stage ( p = 0.05) and AdipoR2 mRNA expression was significantly lower in patients with smoker's bronchiolitis ( p = 0.01) and emphysema ( p = 0.03). Patients with expression of AdipoR1 had longer overall survival. AdipoR2 expression was not correlated with patients' survival. In conclusion, we suggest that expression of AdipoR1 is indicative of favorable prognosis and may be used as prognostic marker in NSCLC.
REBA Myco-ID is a highly sensitive and specific assay for detecting M. tuberculosis and NTM. M. tuberculosis is the main cause of granulomatous lymphadenitis.
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