Histone Deacetylase Inhibitor M344 Inhibits Cell Proliferation and Induces Apoptosis in Human THP-1 Leukemia Cells.

Histone acetylation plays an important role in the silencing and activation of genes involved in tumoregenesis. Trichostatin A, originally identified as an anti-fungal drug, is a potent inhibitor of histone deacetylase (HDAC) with potential anti-tumor activity. In this study, we investigated the effect of M344, an amide analogues of trichostatin A, on the growth and differentiation of THP-1 human leukemia cells.

Differentiation-Associated Expression of Conventional Protein Kinase C Isoforms in Primary Cultures of Bone Marrow Cells Induced by M-CSF and G-CSF.

The Protein kinase C (PKC) -associated signal pathway plays crucial roles in regulation of cell growth, differentiation and apoptosis. The present study focuses on conventional PKC (cPKC) expression and its regulation in primary cultures of bone marrow cells induced to undergo macrophage/granulocyte differentiation by macrophage colony-stimulating factor (M-CSF) or granular colony-stimulating factor (G-CSF). By performing western blot analysis with pan anti-PKC antibodies, we found that PKC is transiently induced by M-CSF, reaching a maximum level by day 2, and then declines and diminishes by day 9 in primary culture of bone marrow cells.

Erythromycin inhibits wear debris-induced inflammatory osteolysis in a murine model.

Up to 20% of patients with total joint arthroplasty will develop radiographic evidence of aseptic loosening (AL), which most likely results from an inflammatory response to billions of wear debris shed from the implant. Our previous work has demonstrated that erythromycin (EM), a macrolide antibiotic, inhibits wear debris-induced inflammatory osteoclastogenesis through the reduction of cytokine production and osteoclast differentiation, both of which involve the NF-kappaB pathway. The aim of the current study was to determine whether EM inhibits wear debris-induced inflammatory osteolysis in a murine osteolysis model.

Prevention of colorectal cancer using COX-2 inhibitors: basic science and clinical applications.

Cyclooxygenase-2 (COX-2), an inducible prostaglandin G/H synthase, is overexpressed in pre-neoplastic tissues and several human cancers including colorectal cancer. Evidence linking COX-2 activity to carcinogenesis was derived from epidemiologic studies and animal models with defect adenomatous polyposis coli (APC) gene. PGE2 induced by COX-2 exerts several biological properties that may be advantageous for tumorigenesis: 1) Promoting angiogenesis (increased VEGF, bFGF, and PDGF production), 2) Anti-apoptosis mechanism (via increased bcl-2 and Akt activity), 3) Stimulating tumor metastasis (by increasing matrix metalloproteinases) and 4) Decreased immune surveillance (decreased cytokine production and NK activity).

Erythromycin inhibits wear debris-induced osteoclastogenesis by modulation of murine macrophage NF-kappaB activity.

Activation of nuclear factor kappa B (NF-kappaB) signaling in response to cell stimulation by wear debris may be critical in the pathogenesis of aseptic loosening. Erythromycin (EM), a macrolide antibiotic, has been shown to effectively suppress some types of inflammatory reactions. In this study, we examined the effect of EM on wear debris-induced osteoclastic bone resorption in vitro.

Cleavage of Bcl-2 Protein by Activated Caspase-3 Is Associated with Inactivation of Lyn(p53/56) Kinase Activity in Human M-07e Leukemic Cells during Apoptosis.

The growth of M-07e human megakaryocytic leukemia cells is strictly dependent on GM-CSF. In M-07e cells, the GM-CSF receptor (GM-CSF R) is composed of two subunits: a low affinity alpha subunit and a phosphorylated beta subunit, which is constitutively linked to lyn(53/56) protein tyrosine kinase. In this study, The role of lyn kinase in regulating TGF-beta 1-induced apoptosis in M-07e cells was examined.

XK469, a novel antitumor agent, inhibits signaling by the MEK/MAPK signaling pathway.

Purpose: XK469 (NSC 697887) is a novel antitumor agent with broad activity against a variety of tumors including drug-resistant tumors. Previous studies have indicated that XK469 is an antiproliferative agent with a low cytotoxic effect in human H116 tumor cells. In this study, we sought to determine the signaling pathways involved in mediating its antiproliferative activity.

Activation of the MEK/MAPK pathway is involved in bryostatin1-induced monocytic differenciation and up-regulation of X-linked inhibitor of apoptosis protein.

Induction of monocytic differentiation by bryostatin1 (bryo1) conferred on THP-1 leukemia cells the ability to resist Z-LLL-CHO-induced apoptosis. The mechanism of resistance developed during this process was investigated. Apoptosis resistance was associated with an enhanced expression of X-linked inhibitor of apoptosis protein (XIAP), an endogenous caspase inhibitor, in differentiated THP-1 cells.

Mitotic arrest induced by XK469, a novel antitumor agent, is correlated with the inhibition of cyclin B1 ubiquitination.

XK469 (NSC 697887) is a novel antitumor agent with broad activity against a variety of tumors. Previous studies suggest that XK469 is a topoisomerase II beta poison with functional activity similar to that of 4'-(9-acridinylamino) methanesulfon-m-anisidide (m-AMSA). The goal of our study was to investigate its mechanism of action further using a human HCT-116 (H116) colon tumor cell model.