One mechanism of tumour suppression by pRb is repressing E2F1. Hence, E2f1 deletion diminishes tumorigenesis following Rb1 loss. However, E2F1 promotes both proliferation and apoptosis. It therefore remains unclear how de-repressed E2F1 promotes tumorigenesis. Another mechanism of pRb function is repressing Skp2 to elevate p27 to arrest proliferation. However, Skp2 deletion induced apoptosis, n...

Diabetes mellitus is associated with decreased NO bioavailability in the myocardium. Ginsenoside Rb1 has been shown to confer cardioprotection against ischemia reperfusion injury. The aim of this study was to investigate whether Ginsenoside Rb1 exerts cardioprotective effects during myocardial ischemia-reperfusion in diabetic rats and whether this effect is related to increase the production of...

Angiogenesis is the formation of new blood vessels from the existing vasculature, which is involved in multiple biological processes, including atherosclerosis, ischemic heart disease, and cancer. Ginsenoside-Rb1 (Rb1), the most abundant ginsenoside isolated form Panax ginseng, has been identified as a promising anti-angiogenic agent via the up-regulation of PEDF. However, the underlying molecu...

Mutations in the retinoblastoma tumor suppressor gene (rb1) cause both sporadic and familial forms of childhood retinoblastoma. Despite its clinical relevance, the roles of rb1 during normal retinotectal development and function are not well understood. We have identified mutations in the zebrafish space cadet locus that lead to a premature truncation of the rb1 gene, identical to known mutatio...

We examined loss of heterozygosity (LOH) at the retinoblastoma susceptibility gene (RB1) locus on chromosome 13q14 in 20 non-small-cell lung cancers (NSCLCs) using polymorphic markers. The expression of RB protein was examined by immunohistochemical analysis of paraffin-embedded specimens of the same tumors. The results revealed that 10 of 16 informative cases showed an LOH at the RB1 locus, wh...

The pocket protein (PP) family consists of the three members RB1, p107 and p130 all possessing tumor suppressive properties. Indeed, the PPs jointly control the G1/S transition mainly by inhibiting E2F transcription factors. Notably, several viral oncoproteins are capable of binding and inhibiting PPs. Merkel cell polyomavirus (MCPyV) is considered as etiological factor for Merkel cell carcinom...

The retinoblastoma tumor suppressor gene (RB1; encoding RB) is often cited as a gatekeeper, whose inactivation - direct or indirect - is a rate-limiting step for tumor initiation. However, in this issue of the JCI, Sharma et al. show that RB1 loss is a late event in human prostate cancer that is coincident with the emergence of castrate-resistant metastatic disease. This role for RB1 was linked...

Cultured Schwann cells were treated with 5.6 mM and 50 mM glucose alternating every 8 hours to simulate intermittent high glucose. The present study analyzed the neuroprotective effects of 1, 10 and 100 μM ginsenoside Rb1 on oxidative damage and apoptosis in Schwann cells induced by intermittent high glucose. Flow cytometry demonstrated that ginsenoside Rb1 reduced intermittent high glucose-med...

The retinoblastoma tumor suppressor gene (RB1) is inactivated in hereditary and sporadic forms of retinoblastoma as well as in a number of other sporadic tumors. The majority of human pituitary tumors have been shown to be monoclonal neoplasms, suggesting that 1 or more somatic mutations are involved in the clonal expansion of a single progenitor cell. Recently, a high percentage of transgenic ...

BACKGROUND To evaluate the impact of dihydrofolate reductase (DHFR) and reduced folate carrier (RFC) genes on methotrexate (MTX) resistance in osteosarcoma cells in relation to retinoblastoma (RB1) gene status. MATERIALS AND METHODS A series of human osteosarcoma cell lines-either sensitive or resistant to MTX-and 16 osteosarcoma tumour samples were used in this study. RESULTS In U-2OS MTX-...