Salvatore De Maria

Simvastatin inhibits cancer cell growth by inducing apoptosis correlated to activation of Bax and down-regulation of BCL-2 gene expression

The statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) have been proven to be effective in lowering cholesterol and as anti-lipid agents against cardiovascular disease. Recent reports demonstrate an anticancer effect induced by the statins through inhibition of cell proliferation. Probably, these effects are due to suppression of the mevalonate pathway leading to the depletion of various downstream products that play an essential role in cell cycle progression, cell signaling and membrane integrity. To date, although many hypotheses have been proposed, the exact mechanism at the basis of cancer cell growth arrest induced by statins is not known. In this study, we have demonstrated that simvastatin, at a dose of 20 μM for 24–72 h, induced in cancer cells but not in normal cells precise features of apoptosis including increased DNA fragmentation while, at the molecular level simvastatin induced overexpression of the pro-apoptotic gene Bax together with an inhibition of BCL-2, the gene that has the well-known function of protecting cells from apoptosis. The simvastatin-mediated induction of apoptosis in similar cancer cells but not in normal cells is very interesting and may be at the basis of cancer therapy using statins, usually in combination with chemotherapy or to be used as a cancer protective drug. Simvastatin may, thus, play a dual prophylactic role as a lipid-lowering drug for the prevention of heart disease and as an anticancer agent to prevent certain types of cancers.

EVIDENCE FOR MULTIPLE RAT VPAC1 RECEPTOR STATES WITH DIFFERENT AFFINITIES FOR AGONISTS

We compare the binding properties of [125I-VIP] and [125I]-Ro 25 1553 to VPAC1 receptors, expressed in stably transfected CHO cells. [125I]-VIP labelled two VPAC1 receptor states, while [125I]-Ro 25 1553 labelled selectively a limited number of high-affinity receptors. This high-affinity state probably corresponds to an agonist-receptor-Gs ternary complex as its properties (guanyl nucleotides, EC50 values and maximal effect) were affected by cholera toxin pre-treatment. Both high- and low-affinity receptors participated in the adenylate cyclase activation. This suggested that agonists activate not only low-affinity uncoupled receptors by facilitating the ternary complex formation, but also activated the high-affinity ternary complex by accelerating the GTP binding to emptied, receptor-bound G proteins.

The immunomodulatory protein SV-IV protects serum-deprived cells against apoptosis but not against G0/G1 arrest: possible implications for the survival of implanting embryo.

Serum deprivation induced in human lymphoblastoid Raji cells oxidative stress‐associated apoptotic death and G0/G1 cell cycle arrest. Addition into culture medium of the immunomodulatory protein Seminal vesicle protein 4 (SV‐IV) protected these cells against apoptosis but not against cycle arrest. The antiapoptotic activity was related to: (1) decrease of endocellular reactive Oxygen species (ROS) (2) increase of mRNAs encoding anti‐oxidant enzymes (catalase, G6PD) and antiapoptotic proteins (survivin, cox‐1, Hsp70, c‐Fos); (3) decrease of mRNAs encoding proapoptotic proteins (c‐myc, Bax, caspase‐3, Apaf‐1). The biochemical changes underlaying these effects were probably induced by a protein tyrosine kinase (PTK) activity triggered by the binding of SV‐IV to its putative plasma membrane receptors. The ineffectiveness of SV‐IV to abrogate the cycle arrest was accounted for by its downregulating effects on D1,3/E G1‐cyclins and CdK2/4 gene expression, ppRb/pRb ratio, and intracellular ROS concentration. In conclusion, these experiments: (1) prove that SV‐IV acts as a cell survival factor; (2) suggest the involvement of a PTK in SV‐IV signaling; (3) point to cell cycle‐linked enzyme inhibition as responsible for cycle arrest; (4) provide a model to dissect the cycle arrest and apoptosis induced by serum withdrawal; (5) imply a possible role of SV‐IV in the survival of hemiallogenic implanting embryos. J. Cell. Physiol. 212:610–625, 2007.

In vitro stimulatory effect of anti-apoptotic seminal vesicle protein 4 on purified peroxidase enzymes.

The enzymatic activities of purified horseradish peroxidase, selenium‐dependent glutathione peroxidase, thyroid peroxidase and myeloperoxidase, but not that of lactoperoxidase, were markedly enhanced when added into a reaction mixture containing 5 μm native seminal vesicle protein 4, a major protein secreted from rat seminal vesicle epithelium. A further increase of horseradish peroxidase activity was obtained using Ser58‐phosphorylated or acetylated seminal vesicle protein 4. The activating effect of native seminal vesicle protein 4 was highest (about 60‐fold) on horseradish peroxidase when 4‐chloro‐1‐naphtol was used as the electron donor substrate. The main kinetics parameters of the stimulatory effect on horseradish peroxidase were evaluated and the enzyme–electron donor substrate interaction was investigated by HPLC and electrospray‐MS. A native seminal vesicle protein 4/4‐chloro‐1‐naphtol noncovalent adduct was detected when the protein and 4‐chloro‐1‐naphtol were present in the appropriate molar ratio in the horseradish peroxidase‐catalyzed reaction. By contrast, no adducts were formed between native seminal vesicle protein 4 and horseradish peroxidase. This native seminal vesicle protein 4/4‐chloro‐1‐naphtol interaction might underlie the native seminal vesicle protein 4‐induced horseradish peroxidase stimulation. Furthermore, native seminal vesicle protein 4 was shown by spectrophotometric and electrospray‐MS analysis to interact with NADPH, an electron donor substrate of the selenium‐dependent glutathione peroxidase/glutathione reductase redox system, with formation of an adduct between them. Although further investigation is required to elucidate the mechanism of adduct formation, this interaction, probably by promoting the release of the NADPH electrons required for glutathione disulphide reduction, could explain the stimulatory effect of seminal vesicle protein 4 on mammalian peroxidases possibly involved in its physiological function on the selenium‐dependent glutathione peroxidase/glutathione reductase system. The biological significance of these properties of native seminal vesicle protein 4 might be related to its ability to downregulate reactive oxygen species and oxidative stress‐induced apoptosis.

Polydatin, natural precursor of resveratrol, promotes osteogenic differentiation of mesenchymal stem cells

Bone loss and fractures are consequences of aging, diseases or traumas. Furthermore the increased number of aged people, due to the rise of life expectancy, needs more strategies to limit the bone loss and regenerate the lost tissue, ameliorating the life quality of patients. A great interest for non-pharmacological therapies based on natural compounds is emerging and focusing on the oligostilbene Polydatin, present in many kinds of fruits and vegetables, when resveratrol particularly in red wines. These molecules have been extensively studied due to their antioxidant and anti-inflammatory effects, showing more recently Resveratrol the ability to enhance osteogenic differentiation and bone formation. However, the clinical applications of Resveratrol are limited due to its low bioavailability and rapid metabolism, while its natural glycosilated precursor Polydatin shows better metabolic stability and major abundance in fresh fruits and vegetables. Nevertheless the role of Polydatin on osteogenic differentiation is still unexplored. Mesenchymal stem cells (MSCs) from dental tissues, such as dental bud stem cells (DBSCs), are able to differentiate toward osteogenic lineage: thus we investigated how Resveratrol and Polydatin influence the differentiation of DBSCs, eventually affecting bone formation. Our results showed that Polydatin increases MSCs osteogenic differentiation sharing similar properties with Resveratrol. These results encourage to deepen the effects of this molecule on bone health and its associated mechanisms of action, wishing for the future a successful use in bone loss prevention and therapy.

Antiapoptotic Seminal Vesicle Protein IV Induces Histamine Release from Human FcεRI+ Cells

Background: Seminal vesicle protein number 4 (SV-IV) is a small, basic, multifunctional, intrinsically disordered secretory protein synthesized in large amounts by rat seminal vesicle epithelium under androgen transcriptional control. SV-IV-immunorelated proteins occur in other rat tissues and in humans. Methods: The in vitro effect of SV-IV on human FcΕRI+ cells was investigated by standard immunologic, biochemical and molecular biology procedures. Results: SV-IV-induced histamine release from human basophils and lung mast cells without any influence on leukotriene C4 release and cell migration. The histamine release rate was slower compared with that induced by anti-IgE, the temperature dependence of the event being similar. SV-IV-induced histamine release was Ca2+-dependent, suggesting a physiological interaction of the protein with FcΕRI+ cells. SV-IV and anti-IgE acted synergistically on the histamine release. SV-IV did not induce de novo synthesis of cytokines and growth factors (transforming growth factor-β1, interleukin-10, interleukin-13, tumor necrosis factor-α, vascular endothelial growth factor A) in FcΕRI+ cells. Conclusions: SV-IV protein induces in human FcΕRI+ cells the release of histamine, a proinflammatory, antiapoptotic and immunosuppressive biogenic amine. These data: (1) are consistent with the antiapoptotic and immunosuppressive properties of SV-IV; (2) confirm a regulatory feature of SV-IV on mammal inflammatory reactivity by either inhibiting the arachidonate cascade pathway or stimulating proinflammatory cytokine release from lymphocyte/monocytes and histamine from FcΕRI+ cells; (3) raise the possibility of a protective role of SV-IV on implanting hemiallogenic blastocysts against maternal reactive oxygen species and immunological attacks at the uterine implantation site.