Cellular subtype expression and activation of CaMKII regulate the fate of atherosclerotic plaque.

BACKGROUND AND AIMS: Atherosclerosis is a degenerative process of the arterial wall implicating activation of macrophages and proliferation of vascular smooth muscle cells. Calcium-calmodulin dependent kinase type II (CaMKII) in vascular smooth muscle cells (VSMCs) regulates proliferation, while in macrophages, this kinase governs diapedesis, infiltration and release of extracellular matrix enzymes. We aimed at understanding the possible role of CaMKII in atherosclerosis plaques to regulate plaque evolution towards stability or instability. METHODS: Clinically defined stable and unstable plaques obtained from patients undergoing carotid end arteriectomy were processed for evaluation of CaMKs protein expression, activity and localization. RESULTS: The larger content of CaMKII was found in CD14+myeloid cells that were more abundant in unstable rather than stable plaques. To test the biological effect of activated CD14+myeloid cells, VSMCs were exposed to the conditioned medium (CM) of macrophages extracted from carotid plaques. CM induced attenuation of CaMKs expression and activity in VSMCs, leading to the reduction of VSMCs proliferation. This appears to be due to the CaMKII dependent release of cytokines. CONCLUSIONS: These results indicate a pivotal role of CaMKs in atherosclerosis by regulating activated myeloid cells on VSMCs activity. CaMKII could represent a possible target for therapeutic strategies based on macrophages specific inhibition for the stabilization of arteriosclerotic lesions.

Oxidative Stress Mediates the Antiproliferative Effects of Nelfinavir in Breast Cancer Cells.

The discovery of the anti-proliferative activity of nelfinavir in HIV-free models has encouraged its investigation as anticancer drug. Although the molecular mechanism by which nelfinavir exerts antitumor activity is still unknown, its effects have been related to Akt inhibition. Here we tested the effects of nelfinavir on cell proliferation, viability and death in two human breast cancer cell lines and in human normal primary breast cells. To identify the mechanism of action of nelfinavir in breast cancer, we evaluated the involvement of the Akt pathway as well as the effects of nelfinavir on reactive oxygen species (ROS) production and ROS-related enzymes activities. Nelfinavir reduced breast cancer cell viability by inducing apoptosis and necrosis, without affecting primary normal breast cells. The antitumor activity of nelfinavir was related to alterations of the cell redox state, coupled with an increase of intracellular ROS production limited to cancer cells. Nelfinavir treated tumor cells also displayed a downregulation of the Akt pathway due to disruption of the Akt-HSP90 complex, and subsequent degradation of Akt. These effects resulted to be ROS dependent, suggesting that ROS production is the primary step of nelfinavir anticancer activity. The analysis of ROS-producers and ROS-detoxifying enzymes revealed that nelfinavir-mediated ROS production was strictly linked to flavoenzymes activation. We demonstrated that ROS enhancement represents the main molecular mechanism required to induce cell death by nelfinavir in breast cancer cells, thus supporting the development of new and more potent oxidizing molecules for breast cancer therapy.

Good at Heart: Preserving Cardiac Metabolism during aging.

The natural process of aging determinates several cardiac modifications with increased susceptibility to heart diseases and ultimately converging on development of chronic heart failure as final stage. These changes mainly include left ventricular hypertrophy, diastolic dysfunction, valvular degeneration, increased cardiac fibrosis, increased prevalence of atrial fibrillation, and decreased maximal exercise capacity, as demonstrated in several humans and animal models of aging. While different theories have been proposed to explain the natural process of aging, it is clear that most of the alterations affect mechanisms involved in cell homeostasis and maintenance. Latest research studies have in particular focused on role of mitochondrial oxidative stress, energy production and mitochondria quality control. This article reviews the central role played by this organelle in aging and the role of new molecular players involved into the progression toward heart failure and potentially susceptible of new "anti-aging" strategies.

Metabolic Syndrome and Aging: Calcium Signaling as Common Regulator.

Aging is one of the most important societal challenges that western societies face, as a result of longer life expectancy and reduced natality rates. Aging is a success story of our health and social systems, but raises sustainability issues that are linked to the increased need for services of older adults, due to the reduction of their independence and to the co-existence of multiple chronic diseases. The metabolic syndrome can be considered an age-related disease, since its prevalence increases with age. Current demographic trends in the population highlight aging-related dysfunctions that contribute to the onset of several metabolic diseases, and the need for innovative, effective and sustainable approaches. This review describes the correlation between the metabolic syndrome and aging, and the underlying common molecular mechanisms, focusing on calcium signaling and its crosstalks.

A novel crosstalk between calcium/calmodulin kinases II and IV regulates cell proliferation in myeloid leukemia cells.

CaMKs link transient increases in intracellular Ca(2+) with biological processes. In myeloid leukemia cells, CaMKII, activated by the bcr-abl oncogene, promotes cell proliferation. Inhibition of CaMKII activity restricts cell proliferation, and correlates with growth arrest and differentiation. The mechanism by which the inhibition of CaMKII results in growth arrest and differentiation in myeloid leukemia cells is still unknown. We report that inhibition of CaMKII activity results in an upregulation of CaMKIV mRNA and protein in leukemia cell lines. Conversely, expression of CaMKIV inhibits autophosphorylation and activation of CaMKII, and elicits G0/G1cell cycle arrest,impairing cell proliferation. Furthermore, U937 cells expressing CaMKIV show elevated levels of Cdk inhibitors p27(kip1) and p16(ink4a) and reduced levels of cyclins A, B1 and D1. These findings were also confirmed in the K562 leukemic cell line. The relationship between CaMKII and CaMKIV is also observed in primary acute myeloid leukemia (AML) cells, and it correlates with their immunophenotypic profile. Indeed, immature MO/M1 AML showed increased CaMKIV expression and decreased pCaMKII, whereas highly differentiated M4/M5 AML showed decreased CaMKIV expression and increased pCaMKII levels. Our data reveal a novel cross-talk between CaMKII and CaMKIV and suggest that CaMKII suppresses the expression of CaMKIV to promote leukemia cell proliferation.

Synthesis, in vitro, and in cell studies of a new series of [indoline-3,2'-thiazolidine]-based p53 modulators.

Analogues of the previously described spiro[imidazo[1,5-c]thiazole-3,3'-indoline]-2',5,7(6H,7aH)-trione p53 modulators were prepared to explore new structural requirements at the thiazolidine domain for the antiproliferative activity and p53 modulation. In cell, antiproliferative activity was evaluated against two human tumor cell lines. Derivative 5-bromo-3'-(cyclohexane carbonyl)-1-methyl-2-oxospiro[indoline-3,2'-thiazolidine] (4n) emerged as the most potent compound of this series, inhibiting in vitro 30% of p53-MDM2 interaction at 5 µM and the cell growth of different human tumor cells at nanomolar concentrations. Docking studies confirmed the interactions of 4n with the well-known Trp23 and Phe19 clefts, explaining the reasons for its binding affinity for MDM2. 4n at 50 nM is capable of inducing the accumulation of p53 protein, inducing significant apoptotic cell death without affecting the cell cycle progression. Comparative studies using nutlin in the same cellular system confirm the potential of 4n as a tool for increasing understanding of the process involved in the nontranscriptional proapoptotic activities of p53.