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Adipose tissue plays a crucial role in regulating metabolic homeostasis, and its dysfunction in obesity leads to insulin resistance and type 2 diabetes (T2D). White adipose tissue (WAT) primarily stores energy as lipids, while brown adipose tissue (BAT) regulates thermogenesis by dissipating energy as heat. The process of browning involves the transdifferentiation of WAT into brown-like or beige adipocytes, which exhibit a similar phenotype as BAT. The browning of WAT is an attractive approach against obesity and T2D, and the activation of the energy sensor AMP-activated protein kinase (AMPK) has been shown to play a role in browning. Carnosic acid (CA), a polyphenolic diterpene, found in many plants including rosemary, is reported to possess potent antioxidant, anti-inflammatory, and anti-hyperglycemic properties. The limited evidence available indicates that CA activates AMPK and may have anti-obesity and antidiabetic potential; however, the effects in adipocyte browning remain largely unexplored. This study aimed to examine the effects of CA on the markers of adipocyte browning. The treatment of 3T3L1 adipocytes with CA activated AMPK, reduced lipid accumulation, and increased the expression of browning protein markers (UCP-1, PGC-1α, PRDM16, and TFAM) and mitochondrial biogenesis. The use of compound C, an AMPK inhibitor, significantly attenuated the effects of CA, indicating AMPK involvement. These studies demonstrate that CA can activate AMPK and stimulate the browning of white adipocytes. Future animal and human studies are required to examine the effects of CA in vivo. [ABSTRACT FROM AUTHOR]

In the classical insulin target tissues of liver, muscle, and adipose tissue, chronically elevated levels of free fatty acids (FFA) impair insulin signaling. Insulin signaling molecules are also present in β-cells where they play a role in β-cell function. Therefore, inhibition of the insulin/insulin-like growth factor 1 pathway may be involved in fat-induced β-cell dysfunction. To address the role of β-cell insulin resistance in FFA-induced β-cell dysfunction we co-infused bisperoxovanadate (BPV) with oleate or olive oil for 48 hours in rats. BPV, a tyrosine phosphatase inhibitor, acts as an insulin mimetic and is devoid of any antioxidant effect that could prevent β-cell dysfunction, unlike most insulin sensitizers. Following fat infusion, rats either underwent hyperglycemic clamps for assessment of β-cell function in vivo or islets were isolated for ex vivo assessment of glucose-stimulated insulin secretion (GSIS). We also incubated islets with oleate or palmitate and BPV for in vitro assessment of GSIS and Akt (protein kinase B) phosphorylation. Next, mice with β-cell specific deletion of PTEN (phosphatase and tensin homolog; negative regulator of insulin signaling) and littermate controls were infused with oleate for 48 hours, followed by hyperglycemic clamps or ex vivo evaluation of GSIS. In rat experiments, BPV protected against fat-induced impairment of β-cell function in vivo, ex vivo, and in vitro. In mice, β-cell specific deletion of PTEN protected against oleate-induced β-cell dysfunction in vivo and ex vivo. These data support the hypothesis that β-cell insulin resistance plays a causal role in FFA-induced β-cell dysfunction. [ABSTRACT FROM AUTHOR]

Prostate cancer, accounting for 375,304 deaths in 2020, is the second most prevalent cancer in men worldwide. While many treatments exist for prostate cancer, novel therapeutic agents with higher efficacy are needed to target aggressive and hormone-resistant forms of prostate cancer, while sparing healthy cells. Plant-derived chemotherapy drugs such as docetaxel and paclitaxel have been established to treat cancers including prostate cancer. Carnosic acid (CA), a phenolic diterpene found in the herb rosemary (Rosmarinus officinalis) has been shown to have anticancer properties but its effects in prostate cancer and its mechanisms of action have not been examined. CA dose-dependently inhibited PC-3 and LNCaP prostate cancer cell survival and proliferation (IC50: 64, 21 µM, respectively). Furthermore, CA decreased phosphorylation/activation of Akt, mTOR, and p70 S6K. A notable increase in phosphorylation/activation of AMP-activated kinase (AMPK), acetyl-CoA carboxylase (ACC) and its upstream regulator sestrin-2 was seen with CA treatment. Our data indicate that CA inhibits AKT-mTORC1-p70S6K and activates Sestrin-2-AMPK signaling leading to a decrease in survival and proliferation. The use of inhibitors and small RNA interference (siRNA) approaches should be employed, in future studies, to elucidate the mechanisms involved in carnosic acid's inhibitory effects of prostate cancer. [ABSTRACT FROM AUTHOR]

Non-small cell lung cancer (NSCLC) represents 80% of all lung cancer cases and is characterized by low survival rates due to chemotherapy and radiation resistance. Novel treatment strategies for NSCLC are urgently needed. Liver kinase B1 (LKB1), a tumor suppressor prevalently mutated in NSCLC, activates AMP-activated protein kinase (AMPK) which in turn inhibits mammalian target of rapamycin complex 1 (mTORC1) and activates unc-51 like autophagy activating kinase 1 (ULK1) to promote autophagy. Sestrin-2 is a stress-induced protein that enhances LKB1-dependent activation of AMPK, functioning as a tumor suppressor in NSCLC. In previous studies, rosemary (Rosmarinus officinalis) extract (RE) activated the AMPK pathway while inhibiting mTORC1 to suppress proliferation, survival, and migration, leading to the apoptosis of NSCLC cells. In the present study, we investigated the anticancer potential of carnosic acid (CA), a bioactive polyphenolic diterpene compound found in RE. The treatment of H1299 and H460 NSCLC cells with CA resulted in concentration and time-dependent inhibition of cell proliferation assessed with crystal violet staining and 3H-thymidine incorporation, and concentration-dependent inhibition of survival, assessed using a colony formation assay. Additionally, CA induced apoptosis of H1299 cells as indicated by decreased B-cell lymphoma 2 (Bcl-2) levels, increased cleaved caspase-3, -7, poly (ADP-ribose) polymerase (PARP), Bcl-2-associated X protein (BAX) levels, and increased nuclear condensation. These antiproliferative and proapoptotic effects coincided with the upregulation of sestrin-2 and the phosphorylation/activation of LKB1 and AMPK. Downstream of AMPK signaling, CA increased levels of autophagy marker light chain 3 (LC3), an established marker of autophagy; inhibiting autophagy with 3-methyladenine (3MA) blocked the antiproliferative effect of CA. Overall, these data indicate that CA can inhibit NSCLC cell viability and that the underlying mechanism of action of CA involves the induction of autophagy through a Sestrin-2/LKB1/AMPK signaling cascade. Future experiments will use siRNA and small molecule inhibitors to better elucidate the role of these signaling molecules in the mechanism of action of CA as well as tumor xenograft models to assess the anticancer properties of CA in vivo. [ABSTRACT FROM AUTHOR]

Simple Summary: Cervical cancer is the fourth most commonly diagnosed cancer among women worldwide. While treatments exist to stop growth of cervical cancer in humans, they are often associated with major side effects and the development of resistance to therapy. Traditionally, plant-derived compounds have been used to treat many ailments, including cancer. The search for novel plant-derived chemicals is important, as they can potentially provide effective treatment with less severe side effects and importantly overcome drug resistance. Genistein and its analogues have been shown to decrease survival and proliferation as well as induce cell death in cell culture models of cervical cancer and reduce tumor volume in a mouse model. More pharmacokinetic studies and studies utilizing preclinical animal models of cervical cancer are required to increase our knowledge of genistein's biological effects, prior to moving to human studies. Cervical cancer is associated with persistent Human Papilloma Virus (HPV) infections and is the fourth most common cancer in women worldwide. Current treatment options; surgery, chemotherapy, and radiation, are often associated with severe side effects including possible infertility. Novel treatment options are required to help combat this disease and reduce side effects. Many plant-derived chemicals, including paclitaxel and docetaxel, are already in use as treatments for various cancers. Genistein is a polyphenolic isoflavone found in foods including soybeans and legumes, and studies have shown that it has various biological effects and anti-cancer properties. This review aims to summarize the existing studies examining the effects of genistein on cervical cancer. All relevant in vitro and in vivo studies are summarized, and the key findings are highlighted in the associated tables. Based on the available in vitro/cell culture studies reported here, genistein inhibits cervical cancer cell proliferation and induces apoptosis. Use of genistein in combination with radiation or chemotherapy agents resulted in enhanced response indicating radio- and chemo-sensitization properties. More animal studies are required to examine the effectiveness of genistein in vivo. Such studies will form the basis for future human studies exploring the potential of genistein to be used in the treatment of cervical cancer. [ABSTRACT FROM AUTHOR]

High glucose-enhanced activation of mesangial cell p38 MAPK by ET-1, ANG II, and platelet-derived growth factor. Am J Physiol Endocrinol Metab 282: E161-E169, 2002.--Mitogen-activated protein kinase (MAPK) p38 is activated in response to stress stimuli and growth factors relevant to the pathogenesis of diabetic nephropathy. We postulated that mesangial cells exposed to high glucose and to endothelin-1 (ET-1), angiotensin II (ANG II), and platelet-derived growth factor (PDGF) demonstrate enhanced p38 activity and subsequent activation of the cAMP responsive element binding (CREB) transcription factor. Primary rat mesangial cells exposed to 5.6 (NG) or 30 mM glucose (HG) or NG plus 24.4 mM sorbitol (osmotic control) for [less than or equal to] 4 days were acutely stimulated with ET-1, ANG II, or PDGF. After 3 days of HG, p38 phosphorylation and kinase activity increased twofold (P < 0.05 vs. NG, n = 5). No change in p38 activity was observed with sorbitol. In HG, activation of p38 by ET-1, ANG II, or PDGF was enhanced compared with NG and was protein kinase C (PKC) independent. In HG, CREB phosphorylation in response to ET-1, ANG II, and PDGF stimulation was enhanced compared with NG and was abolished by p38 inhibition with SB202190. To conclude, in HG, mesangial cell p38 is activated, which in turn stimulates CREB phosphorylation. Furthermore, in HG, mesangial cell p38 responsiveness to ET-1, ANG II, and PDGF and consequent CREB phosphorylation are enhanced through a PKC-independent pathway, which may contribute to the pathogenesis of diabetic nephropathy. activating transcription factor 2; cyclic adenosine triphosphate-responsive element binding; protein kinase C