Plasma Rhenium and Selenium Concentrations After Repeated Daily Oral Administration of Rhenium(I)-diselenoether in 4T1 Breast Tumor-bearing Mice.

BACKGROUND/AIM: Rhenium(I)-diselenoether (Re-diSe) is a compound combining a rhenium tricarbonyl(I) core with a diselenide ligand. A high dose of 60 mg/kg had a pro-tumor effect in a previous study, in non-immune deficient 4T1 tumor-bearing mice, while doses of 1 and 10 mg/kg did not affect tumor growth, after repeated oral administrations. This study aimed to examine the tumor effects of a lower dose of 0.1 mg/kg with the same experimental design and to assay plasma Re and Se concentrations. MATERIALS AND METHODS: Syngenic BALB/cByJ (JAX) mice were orthotopically inoculated with 4T1 mammary breast cancer cells. Re-diSe was daily administered orally for 23 days at doses of 0.1, 1, and 10 mg/kg, whereas controls received no treatment. Tumor and mice weights were measured at the end of the experiment. Plasma Re and Se concentrations were assayed by an inductively coupled plasma sector field mass spectrometry instrument (ICP-sf-MS). RESULTS: The weight of the tumors did not vary in treated versus non-treated mice. The limit of detection (LOD) of Re was 0.34 nmol/l. Plasma Re concentrations were 14±20 nmol/l at doses of 0.1 mg/kg, and increased at higher doses, up to 792±167 nmol/l at doses of 10 mg/kg. Plasma Se concentrations were significantly increased in mice treated with the dose of 0.1 mg/kg (4,262±1,511 nmol/l) versus controls (1,262±888 nmol/l), but not from 0.1 to 1 mg/kg, nor from 1 to 10 mg/kg. CONCLUSION: The 0.1 mg/kg dose of Re-diSe resulted in detectable plasma Re concentrations and significantly increased plasma Se concentrations. In the future, doses as low as 0.1 mg/kg of Re-diSe will be tested, exploring its potential immune interest as a metronomic schedule of treatment, but in mouse models that readily develop extensive metastatic disease.

Environmental signals perceived by the brain abate pro-metastatic monocytes by dampening glucocorticoids receptor signaling.

While positive social-behavioral factors predict longer survival in cancer patients, the underlying mechanisms are unknown. Since tumor metastasis are the major cancer mortality factor, we investigated how an enriched environment (EE) conductive to enhanced sensory, cognitive and motor stimulation impact metastatic progression in lungs following intravasation in the circulation. We find that mice housed in EE exhibited reduced number of lung metastatic foci compared to control mice housed in a standard environment (SE). Compared to SE mice, EE mice increased lung inflammation as early as 4 days after circulating tumor cells extravasation. The impact of environmental signals on lung metastasis is independent of adrenergic receptors signaling. By contrast, we find that serum corticosterone levels are lower in EE mice and that glucocorticoid receptor (GR) antagonist reduces the number of lung metastasis in SE mice. In addition, the difference of the number of lung metastasis between SE and EE mice is abolished when inflammatory monocytes are rendered deficient in GR signaling. This decreased GR signaling in inflammatory monocytes of SE mice results in an exacerbated inflammatory profile in the lung. Our study shows that not only EE reduces late stages of metastatic progression in lungs but disclose a novel anti-tumor mechanism whereby GR-dependent reprogramming of inflammatory monocytes can inhibit metastatic progression in lungs. Moreover, while inflammatory monocytes have been shown to promote cancer progression, they also have an anti-tumor effect, suggesting that their role is more complex than currently thought.

Relationship between the oxidative status and the tumor growth in transplanted triple-negative 4T1 breast tumor mice after oral administration of rhenium(I)-diselenoether.

BACKGROUND: Selective inhibitory effects of rhenium(I)-diselenoether (Re-diSe) were observed in cultured breast malignant cells. They were attributed to a decrease in Reactive Oxygen Species (ROS) production. A concomitant decrease in the production of Transforming Growth Factor-beta (TGFß1), Insulin Growth Factor 1 (IGF1), and Vascular Endothelial Growth Factor A (VEGFA) by the malignant cells was also observed. AIM: The study aimed to investigate the anti-tumor effects of Re-diSe on mice bearing 4T1 breast tumors, an experimental model of triple-negative breast cancer, and correlate them with several biomarkers. MATERIAL AND METHODS: 4T1 mammary breast cancer cells were orthotopically inoculated into syngenic BALB/c Jack mice. Different doses of Re-diSe (1, 10, and 60 mg/kg) were administered orally for 23 consecutive days to assess the efficacy and toxicity. The oxidative status was evaluated by assaying Advanced Oxidative Protein Products (AOPP), and by the dinitrophenylhydrazone (DNPH) test in plasma of healthy mice, non-treated tumor-bearing mice (controls), treated tumor-bearing mice, and tumors in all tumor-bearing mice. Tumor necrosis factor (TNFα), VEGFA, VEGFB, TGFß1, Interferon, and selenoprotein P (selenoP) were selected as biomarkers. RESULTS: Doses of 1 and 10 mg/kg did not affect the tumor weights. There was a significant increase in the tumor weights in mice treated with the maximum dose of 60 mg/kg, concomitantly with a significant decrease in AOPP, TNFα, and TGFß1 in the tumors. SelenoP concentrations increased in the plasma but not in the tumors. CONCLUSION: We did not confirm the anti-tumor activity of the Re-diSe compound in this experiment. However, the transplantation of the tumor cells did not induce an expected pro-oxidative status without any increase of the oxidative biomarkers in the plasma of controls compared to healthy mice. This condition could be essential to evaluate the effect of an antioxidant drug. The choice of the experimental model will be primordial to assess the effects of the Re-diSe compound in further studies.

Idiopathic CD4 T Cell Lymphocytopenia: A Case of Overexpression of PD-1/PDL-1 and CTLA-4.

Idiopathic CD4 T cell lymphocytopenia (ICL) is a rare entity characterized by CD4 T cell count of <300 cells/mm3 along with opportunistic infection for which T cell marker expression remains to be fully explored. We report an ICL case for which T lymphocyte phenotype and its costimulatory molecules expression was analyzed both ex vivo and after overnight stimulation through CD3/CD28. The ICL patient was compared to five healthy controls. We observed higher expression of inhibitory molecules PD-1/PDL-1 and CTLA-4 on CD4 T cells and increased regulatory T cells in ICL, along with high activation and low proliferation of CD4 T cells. The alteration in the expression of both the costimulatory pathway and the apoptotic pathway might participate to down-regulate both CD4 T cell functions and numbers observed in ICL.

Immunosuppressive Tumor Microenvironment Status and Histological Grading of Endometrial Carcinoma.

The recent successes of new cancer immunotherapy approaches have led to investigate their relevance in the context of the Endometrial Carcinoma (EC). These therapies, that take the tumor-induced immunosuppressive microenvironment into account, target the tumor immune escape, in particular the inhibitory receptors involved in the regulation of the effector T cells' activity (immune checkpoints). The aim of this study was to identify, in ECs, differences in intergrades immune status that could contribute to the differences in tumor aggressiveness, and could also be used as theranostic tools. The immune status of tumors was assessed by quantitative real-time PCR. We analyzed the expression of specific genes associated to specific leukocytes subpopulations and the expression of reporting genes associated with the tumor escape/resistance. This study highlights significant differences in the EC intergrades immune status especially the tumor-infiltrating cell types and their activation status as well as in the molecular factors produced by the environment. The immune microenvironment of grade 1 ECs hints at a robust tumoricidal milieu while that of higher grades is more evocative of a tolerogenic milieu. This genes-based immunological monitoring of tumors that easily highlights significant intergrade differences relating to the density, composition and functional state of the leukocyte infiltrate, could give solid arguments for choosing the best therapeutic options, especially those targeting immune checkpoints. Moreover it could enable an easy adaptation of individual treatment approaches for each patient.

Understanding the Progression of Bone Metastases to Identify Novel Therapeutic Targets.

Bone is one of the most preferential target site for cancer metastases, particularly for prostate, breast, kidney, lung and thyroid primary tumours. Indeed, numerous chemical signals and growth factors produced by the bone microenvironment constitute factors promoting cancer cell invasion and aggression. After reviewing the different theories proposed to provide mechanism for metastatic progression, we report on the gene expression profile of bone-seeking cancer cells. We also discuss the cross-talk between the bone microenvironment and invading cells, which impacts on the tumour actions on surrounding bone tissue. Lastly, we detail therapies for bone metastases. Due to poor prognosis for patients, the strategies mainly aim at reducing the impact of skeletal-related events on patients' quality of life. However, recent advances have led to a better understanding of molecular mechanisms underlying bone metastases progression, and therefore of novel therapeutic targets.

Gallium, a promising candidate to disrupt the vicious cycle driving osteolytic metastases.

Bone metastases of breast cancer typically lead to a severe osteolysis due to an excessive osteoclastic activity. On the other hand, the semi-metallic element gallium (Ga) displays an inhibitory action on osteoclasts, and therefore on bone resorption, as well as antitumour properties. Thus, we explored in vitro Ga effects on osteoclastogenesis in an aggressive bone metastatic environment based on the culture of pre-osteoclast RAW 264.7 cells with conditioned medium from metastatic breast tumour cells, i.e. the breast tumour cell line model MDA-MB-231 and its bone-seeking clone MDA-231BO. We first observed that Ga dose-dependently inhibited the tumour cells-induced osteoclastic differentiation of RAW 264.7 cells. To mimic a more aggressive environment where pro-tumourigenic factors are released from bone matrix due to osteoclastic resorption, metastatic breast tumour cells were stimulated with TGF-ß, a mayor cytokine in bone metastasis vicious cycle. In these conditions, we observed that Ga still inhibited cancer cells-driven osteoclastogenesis. Lastly, we evidenced that Ga affected directly and strongly the proliferation/viability of both cancer cell lines, as well as the expression of major osteolytic factors in MDA-231BO cells. With the exception of two small scale clinical studies from 1980s, this is the first time that antitumour properties of Ga have been specifically studied in the context of bone metastases. Our data strongly suggest that, through its action against the vicious cycle involving bone cells and tumour cells, Ga represents a relevant and promising candidate for the local treatment of bone metastases in patients with breast cancer.

Genetic and pharmacological inactivation of the purinergic P2RX7 receptor dampens inflammation but increases tumor incidence in a mouse model of colitis-associated cancer.

Colitis-associated cancer (CAC) is a complication of inflammatory bowel disease (IBD). Binding of extracellular ATP to the purinergic receptor P2RX7 has emerged as a critical event in controlling intestinal inflammation, acting to limit elevation of proinflammatory mast cells and cytokines and promote survival of regulatory T cells (Treg) and enteric neurons. In this study, we investigated the effect of P2RX7 blockade in an established mouse model of CAC. Using genetic and pharmacologic tools, we found unexpectedly that while P2RX7 mediated inflammatory responses, it also acted at an early time to suppress CAC development. P2RX7 blockade enhanced proliferation of intestinal epithelial cells and protected them from apoptosis. The proliferative effects of P2RX7 blockade were associated with an increased production of TGFß1 that was sufficient to stimulate the proliferation of intestinal epithelial cells. Finally, P2RX7 blockade also altered immune cell infiltration and promoted Treg accumulation within lesions of the digestive system. Taken together, our findings reveal an unexpected role for P2RX7 in preventing CAC, suggesting cautions in the use of P2RX7 inhibitors to treat IBD given the possibility of increasing risks CAC as a result.

Therapeutic strategies for treating osteolytic bone metastases.

The recent progress in oncologic management of patients with localized cancer or metastatic disease has permitted a significant improvement in life expectancy. Nevertheless, bone metastases and their consequent skeletal-related events (SREs) are still associated with unfavorable prognosis and greatly affect quality of life. Global management of these bone metastases includes traditional local approaches (surgery, radiotherapy, etc.) and systemic administration of chemotherapeutic agents. This review focuses on treatments specific for bone metastases and, in particular, on inhibitors of bone resorption that are effective for preventing and delaying the development of SREs.

CCL5 neutralization restricts cancer growth and potentiates the targeting of PDGFRß in colorectal carcinoma.

Increased CCL5 levels are markers of an unfavourable outcome in patients with melanoma, breast, cervical, prostate, gastric or pancreatic cancer. Here, we have assessed the role played by CCL5/CCR5 interactions in the development of colon cancer. To do so, we have examined a number of human colorectal carcinoma clinical specimens and found CCL5 and its receptors over-expressed within primary as well as liver and pulmonary metastases of patients compared to healthy tissues. In vitro, CCL5 increased the growth and migratory responses of colon cancer cells from both human and mouse origins. In addition, systemic treatment of mice with CCL5-directed antibodies reduced the extent of development of subcutaneous colon tumors, of liver metastases and of peritoneal carcinosis. Consistently, we found increased numbers of CD45-immunoreactive cells within the stroma of the remaining lesions as well as at the interface with the healthy tissue. In contrast, selective targeting of CCR5 through administration of TAK-779, a CCR5 antagonist, only partially compromised colon cancer progression. Furthermore, CCL5 neutralization rendered the tumors more sensitive to a PDGFRß-directed strategy in mice, this combination regimen offering the greatest protection against liver metastases and suppressing macroscopic peritoneal carcinosis. Collectively, our data demonstrate the involvement of CCL5 in the pathogenesis of colorectal carcinoma and point to its potential value as a therapeutic target.

Helicobacter pylori infection of gastrointestinal epithelial cells in vitro induces mesenchymal stem cell migration through an NF-κB-dependent pathway.

The role of bone marrow-derived mesenchymal stem cells (MSC) in the physiology of the gastrointestinal tract epithelium is currently not well established. These cells can be recruited in response to inflammation due to epithelial damage, home, and participate in tissue repair. In addition, in the case of tissue repair failure, these cells could transform and be at the origin of carcinomas. However, the chemoattractant molecules responsible for MSC recruitment and migration in response to epithelial damage, and particularly to Helicobacter pylori infection, remain unknown although the role of some chemokines has been suggested. This work aimed to get insight into the mechanisms of mouse MSC migration during in vitro infection of mouse gastrointestinal epithelial cells by H. pylori. Using a cell culture insert system, we showed that infection of gastrointestinal epithelial cells by different H. pylori strains is able to stimulate the migration of MSC. This mechanism involves the secretion by infected epithelial cells of multiple cytokines, with a major role of TNFα, mainly via a Nuclear Factor-kappa B-dependent pathway. This study provides the first evidence of the role of H. pylori infection in MSC migration and paves the way to a better understanding of the role of bone marrow-derived stem cells in gastric pathophysiology and carcinogenesis.

Antagonism of chemokine receptor CXCR3 inhibits osteosarcoma metastasis to lungs.

Metastasis continues to be the leading cause of mortality for patients with cancer. Several years ago, it became clear that chemokines and their receptors could control the tumor progress. CXCR3 has now been identified in many cancers including osteosarcoma and CXCR3 ligands were expressed by lungs that are the primary sites to which this tumor metastasize. This study tested the hypothesis that disruption of the CXCR3/CXCR3 ligands complexes could lead to a decrease in lungs metastasis. The experimental design involved the use of the CXCR3 antagonist, AMG487 and 2 murine models of osteosarcoma lung metastases. After tail vein injection of osteosarcoma cells, mice that were systematically treated with AMG487 according to preventive or curative protocols had a significant reduction in metastatic disease. Treatment of osteosarcoma cells in vitro with AMG487 led to decreased migration, decreased matrix metalloproteinase activity, decreased proliferation/survival and increased caspase-independent death. Taken together, our results support the hypothesis that CXCR3 and their ligands intervene in the initial dissemination of the osteosarcoma cells to the lungs and stimulate the growth and expansion of the metastatic foci in later stages. Moreover, these studies indicate that targeting CXCR3 may specifically inhibit tumor metastasis without adversely affecting antitumoral host response.

Silencing of hSlo potassium channels in human osteosarcoma cells promotes tumorigenesis.

Potassium channels, the most diverse superfamily of ion channels, have recently emerged as regulators of carcinogenesis, thus introducing possible new therapeutic strategies in the fight against cancer. In particular, the large conductance Ca(2+)-activated K(+) channels, often referred to as BK channels, are at the crossroads of several tumor-associated processes such as cell proliferation, survival, secretion and migration. Despite the high BK channel expression in osteosarcoma (OS), their function has not yet been investigated in this malignant bone pathology. Here, using stable RNA interference to reduce the expression of hSlo, the human pore-forming alpha-subunit of the BK channel, in human Cal72 OS cells, we show that BK channels play a functional role in carcinogenesis. Our results reveal for the first time that BK channels exhibit antitumoral properties in OS in vivo and affect the tumor microenvironment through the modulation of both chemokine expression and leukocyte infiltration.

Pentoxifylline inhibits liver expression of tumor necrosis factor alpha mRNA following normothermic ischemia-reperfusion.

BACKGROUND: Pentoxifylline (PTX) has been shown to reduce hepatic injury after normothermic ischemia and reperfusion (I-R) in rat liver. AIM: The aim of this study was to evaluate the effects of PTX on liver expression of tumor necrosis factor alpha (TNFalpha) mRNA following normothermic liver I-R. MATERIALS AND METHODS: A segmental normothermic ischemia of the liver was induced in male Lewis rats by occluding the blood vessels including the bile duct to the median and left lateral lobes for 90 min. At the end of ischemia the nonischemic liver lobes were resected. Rats were divided into three groups: group 1, control Ringer lactate administration; group 2, PTX treatment; group 3, sham-operated control rats. PTX (50 mg/kg) was injected intravenously 30 min before and 60 min after induction of ischemia. Survival rates were compared and the serum activities of TNFalpha, serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) were measured. Histology of the liver was assessed 6 h after reperfusion. Liver TNFalpha mRNA was assessed by PCR amplification at 0, 60, 120, and 210 min after reperfusion. RESULTS: PTX treatment significantly increased 7 day survival (93.3%) compared with nontreated control rats (46.6%, p<0.007). The extent of liver necrosis and the release of liver enzymes were significantly decreased after PTX treatment. Serum activities of TNFalpha were significantly decreased and liver expression of TNFalpha mRNA was inhibited after PTX treatment. CONCLUSION: PTX protects the liver from ischemic injury and inhibits liver expression of TNFalpha mRNA.

Hypoxia-reoxygenation-induced chemokine transcription is not prevented by preconditioning or intermittent hypoxia, in mice hepatocytes.

Prolonged ischemia used in liver surgery and/or transplantation causes cellular damage resulting in apoptosis and necrosis. Ischemia-reperfusion (I/R) led Kupffer cells to pro-inflammatory cytokines secretion [tumor necrosis factor (TNF)-alpha, interleukin-1] which involve chemokines secretion by hepatocytes. These chemokines have neutrophil chemotactic properties and neutrophils are involved in the development of I/R-induced necrosis. The aim of this study was to specify the consequence of partial oxygen pressure variation on hepatocyte chemokines synthesis and to verify if intermittent hypoxia and/or preconditioning could decrease it. It was performed on primary cultured mice hepatocytes and Kupffer cells, subjected to continuous, intermittent hypoxia or preconditioning phases, mimicking surgical processes. The chemokine secretion was evaluated by RNase protection assay and enzyme-linked immunosorbent assay method. Only monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-2 (MIP-2) mRNA formation were observed, especially after 1-h hypoxia followed by 10-h (for MCP-1) or 24-h reoxygenation (for MIP-2). In conclusion, TNF-alpha and coculture with Kupffer cells increased hepatocyte chemokines mRNA transcription, whereas surgical split up protocols (intermittent hypoxia and preconditioning) had no significant effect.

Soluble fractalkine prevents monocyte chemoattractant protein-1-induced monocyte migration via inhibition of stress-activated protein kinase 2/p38 and matrix metalloproteinase activities.

In this study, we address the question of the cross-talk between two chemokines that are cosecreted during inflammation, namely monocyte chemoattractant protein-1 (MCP-1) and soluble fractalkine (s-FKN), toward monocyte migration. We found that s-FKN fails to induce MonoMac6 cell migration per se. Interestingly, this chemokine antagonizes transendothelial migration and chemotaxis of MonoMac6 cells and freshly isolated human monocytes induced by MCP-1, indicating a direct effect of s-FKN on monocytic cells. In this study, we found that stress-activated protein kinase (SAPK)1/c-Jun N-terminal kinase 1 and SAPK2/p38 are involved in the control of MCP-1-induced MonoMac6 cell migration. We demonstrated that s-FKN abrogates the MCP-1-induced SAPK2/p38 activation as well as the upstream Pyk2 activity. Furthermore, we observed that s-FKN also inhibits the activity of a major matrix metalloproteinase (MMP), namely MMP-2. Taken collectively, our results indicate that the s-FKN antagonizes the chemoattractant effect of MCP-1 on monocytes, likely by inhibiting crucial signaling pathways, like SAPK2/p38 and MMP-2 activities.

The receptor activator of nuclear factor (NF)-kappaB ligand (RANKL) is a new chemotactic factor for human monocytes.

Bone resorption is regulated by the immune system, where receptor activator of nuclear factor (NF)kappaB ligand (RANKL), a new member of the tumor-necrosis factor family, may contribute to pathological conditions. Due to the role of RANKL in the maturation of monocyte-derived osteoclasts, we hypothesized that RANKL could exert chemotactic properties toward monocytic cells. Our results demonstrate that RANKL induces the migration of MonoMac-6 monocytic cells as well as human freshly isolated total peripheral blood mononuclear cells (PBMC) and CD14+ purified PBMC. RANKL induces the migration of MonoMac-6 cells in a dose-dependent manner and with an efficacy similar to MCP-1. After an 8-h incubation, the soluble form of RANKL (sRANKL) started to exhibit a chemoattractive effect on MonoMac-6 cells, with an increased effect observed up to 24 h. RANKL elicits an additive chemotactic effect to MCP-1. Furthermore, addition of the RANKL decoy receptor osteoprotegerin in the lower well or RANKL in the upper well abrogates the RANKL-induced migration of MonoMac-6 cells, hallmarking a true specific activity. RNase protection assay experiments indicate that exposure of MonoMac-6 cells to RANKL had no significant effect on the expression of a variety of chemokines, known to attract monocytes. This study provides evidence that RANKL behaves as a chemotactic factor for monocytic cells, emphazing the cross-talk between bone and immune systems.

Rat liver ischemia-reperfusion-induced apoptosis and necrosis are decreased by FK506 pretreatment.

The aim of this study was to demonstrate that tacrolimus (FK506) has a hepatoprotective effect by reducing ischemia-reperfusion-induced apoptosis and necrosis, both of which lead to post-surgical liver dysfunction. An ischemia-reperfusion model and primary cultured rat hepatocytes subjected to hypoxic and reoxygenation phases, mimicking the surgical process, were used. c-Jun N-terminal kinase 1/stress-activated protein kinase 1 (JNK1/SAPK1) activation leads to caspase 3 activation, a trigger of apoptosis. The activation status of JNK1/SAPK1 was evaluated by immunoprecipitation or Western-blotting experiments. Apoptosis was assessed by measuring caspase activation and by TUNEL (terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate-biotin nick-end labeling) reaction. Necrosis was assessed histologically. Tacrolimus improved the survival rate of rats subjected to ischemia-reperfusion. After FK506 pretreatment, the liver necrosis rate was reduced, and ischemia-reperfusion-induced JNK1/SAPK1 activation and apoptosis were significantly decreased. In hypoxia-reoxygenation-subjected hepatocytes, tacrolimus reduced JNK1/SAPK1 and caspase 3 activation. In the liver, tacrolimus prevented ischemia-reperfusion-induced apoptosis and necrosis.

Prostaglandin E2 induces interaction between hSlo potassium channel and Syk tyrosine kinase in osteosarcoma cells.

Prostaglandins (PGs) are important mediators of bone response to growth factors, hormones, inflammation, or mechanical strains. In this study, we show that in MG63 osteosarcoma cells, prostaglandin E2 (PGE2) produces the opening of a large conductance Ca2+-dependent K+ channel (BK). This PGE2-mediated channel opening induces the recruitment of various tyrosine-phosphorylated proteins on the hSlo alpha-subunit of BK. Because the C-terminal domain of hSlo encompasses an immunoreceptor tyrosine-based activation motif (ITAM), we show that the Syk nonreceptor tyrosine kinase, reported yet to be expressed mainly in hematopoietic cells, is expressed also in osteoblastic cells, and recruited on this ITAM after a PGE2-induced docking/activation process. We show that Syk/hSlo association is dependent of an upstream Src-related tyrosine kinase activity, in accord with the classical two-step model described for immune receptors. Finally, we provide evidence that this Syk/hSlo interaction does not affect the electrical features of BK channels in osteosarcoma cells. With these data, we would like to suggest the new notion that besides its conductance function, hSlo channel can behave in bone cells, as a true transduction protein intervening in the bone remodeling induced by PGE2.

Diltiazem reduces apoptosis in rat hepatocytes subjected to warm hypoxia-reoxygenation.

Interruption of hepatic blood flow is necessary in surgery, but the liver is sensitive to ischemia and reperfusion. Hypoxia induces an increase in intracellular calcium concentration. In previous studies, we have shown that hypoxia-reoxygenation (H/R) increased calcium influx and induced JNK(1)/SAPK(1) activation which was involved in the triggering of apoptosis. The aim of this study was to demonstrate that diltiazem, a calcium inhibitor, reduced JNK(1)/SAPK(1) activation and consequently could decrease H/R-induced apoptosis. Experiments were performed, in the presence of diltiazem, on primary cultured rat hepatocytes, subjected to warm H/R phases and in a liver ischemia-reperfusion model. The activation status of JNK(1)/SAPK(1) was evaluated by immunoprecipitation and immunohistolocalisation experiments, while apoptosis was assessed by measuring caspase activity and by TUNEL labeling. Diltiazem inhibited H/R-induced JNK(1)/SAPK(1) activation and decreased apoptosis. It could be used to improve postoperative liver function.