The AMP-activated protein kinase (AMPK) has recently been implicated in anoikis resistance. However, the molecular mechanisms that activate AMPK upon matrix detachment remain unexplored. In this study, we show that AMPK activation is a rapid and sustained phenomenon upon matrix deprivation, whereas re-attachment to the matrix leads to its dephosphorylation and inactivation. Because matrix detachment leads to loss of integrin signaling, we investigated whether integrin signaling negatively regulates AMPK activation. However, modulation of focal adhesion kinase or Src, the major downstream components of integrin signaling, failed to cause a corresponding change in AMPK signaling. Further investigations revealed that the upstream AMPK kinases liver kinase B1 (LKB1) and Ca2+/calmodulin-dependent protein kinase kinase β (CaMKKβ) contribute to AMPK activation upon detachment. In LKB1-deficient cells, we found AMPK activation to be predominantly dependent on CaMKKβ. We observed no change in ATP levels under detached conditions at early time points suggesting that rapid AMPK activation upon detachment was not triggered by energy stress. We demonstrate that matrix deprivation leads to a spike in intracellular calcium as well as oxidant signaling, and both these intracellular messengers contribute to rapid AMPK activation upon detachment. We further show that endoplasmic reticulum calcium release-induced store-operated calcium entry contributes to intracellular calcium increase, leading to reactive oxygen species production, and AMPK activation. We additionally show that the LKB1/CaMKK-AMPK axis and intracellular calcium levels play a critical role in anchorage-independent cancer sphere formation. Thus, the Ca2+/reactive oxygen species-triggered LKB1/CaMKK-AMPK signaling cascade may provide a quick, adaptable switch to promote survival of metastasizing cancer cells.
We conclude that hypercholesterolemia leads to excessive lipid peroxidation. Coexistent diminution in antioxidant activity leads to an imbalance between prooxidants and antioxidants, resulting in oxidative stress. Oxidative stress and elevated AI may contribute to atherogenicity in preeclampsia.
Aim:The aim of the study was to analyze the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2) status over 7 years in South Indian women with breast cancer. Further analysis of a subgroup was done to study clinically defined subtypes and the role of preanalytical factors in needle core biopsies (NCBs) and excised specimens.Materials and Methods:This was a retrospective study from January 2010 to December 2016. Patients diagnosed with invasive breast cancer and available immunohistochemistry (IHC) reports of ER, PR, and HER2 status were analyzed. The cases for the year 2016 were analyzed further to observe the impact of preanalytical factors on the IHC staining patterns and surrogate status.Results:A total of 5436 patients were included with a median age of 48 years. Among these, 65% were ≤ 55 years. The overall incidence of hormone receptor (HR)-positive patients was 48%; HER2 positive, 15%; and triple-negative breast cancer (TNBC), 37%. The incidence of HR positive, HER2 positive, and TNBC were 45%, 16%, and 39% and 53%, 13%, and 34% in patients <56 years and over 55 years, respectively (P < 0.001). There was an increase in HR positivity and decrease in TNBCs over time. There was no significant difference in the staining patterns in NCBs and excised specimens.Conclusion:With time, there is an increase in hormone-positive tumors which may be attributed to better IHC techniques and tissue handling. There was no statistical difference in the patterns of ER, PR, and HER2 immunostaining in core biopsy and excised specimens.
Background: Type 2 diabetes mellitus (T2DM) is a chronic disease that is characterized by impaired glucose metabolism and insulin resistance. The objectives of the study were to evaluate the pattern of leptin receptor gene polymorphism Gln223Arg in T2DM and to identify its association with the serum leptin and insulin levels as well as with insulin resistance in diabetes. Methods: In this cross-sectional study, genotyping of leptin receptor was done for Gln223Arg alleles by PCR-restriction fragment length polymorphism in 39 patients with type 2 diabetes. Serum leptin and insulin levels were assayed using enzyme linked sorbent assay in 39 cases and 45 nondiabetic controls. Insulin resistance was calculated by the homeostasis model assessment of insulin resistance (HOMA-IR) formula. Statistical analysis was performed with Graph pad Instat version 3. Results: Hardy–Weinberg Equilibrium for the leptin receptor (LEPR) gene variants showed that alleles were in equilibrium. Leptin levels were insignificantly low in patients with diabetes compared to those in controls. Women in the control group showed significantly higher leptin levels (p < 0.05) compared with men. There was a significant difference in the serum insulin levels and insulin resistance (HOMA-IR) among patients with different genotypes (p = 0.04 and p = 0.0378, respectively). Conclusion: Leptin receptor gene polymorphism affected glucose metabolism by altering insulin resistance and pancreatic beta cells. Thus, single-nucleotide polymorphism of LEPR may affect the pathogenesis of T2DM.
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