Cyclic Adenosine 3',5'-Monophosphate Elevation and Biological Signaling through a Secretin Family Gs-Coupled G Protein-Coupled Receptor Are Restricted to a Single Adenylate Cyclase Isoform.

PC12 cells express five adenylate cyclase (AC) isoforms, most abundantly AC6 and AC7. These two ACs were individually silenced using lentiviral short hairpin RNAs, which lead to a decrease (≥80%) of the protein product of each transcript. These stable PC12 sublines were then used to examine potential AC isoform preference for signaling through a family B G protein-coupled receptor (GPCR).

The host range of gammaretroviruses and gammaretroviral vectors includes post-mitotic neural cells.

Background: Gammaretroviruses and gammaretroviral vectors, in contrast to lentiviruses and lentiviral vectors, are reported to be restricted in their ability to infect growth-arrested cells. The block to this restriction has never been clearly defined. The original assessment of the inability of gammaretroviruses and gammaretroviral vectors to infect growth-arrested cells was carried out using established cell lines that had been growth-arrested by chemical means, and has been generalized to neurons, which are post-mitotic.

Bcl-xL and caspase inhibition increase the survival of rat oxytocin and vasopressin magnocellular neurons in organotypic culture.

Hypothalamic magnocellular neurons (MCNs) are highly vulnerable to axotomy-induced cell death in vivo and in vitro. In this study, we determined whether the anti-apoptotic agent Bcl-xL, a member of the Bcl-2 family which prevents programmed cell death in the central nervous system, can rescue oxytocin (OT) and vasopressin (VP) MCNs in the supraoptic nucleus (SON) in organotypic culture. We found that the novel, membrane permeant form of Bcl-xL that we employed in these studies protected both OT and VP MCNs from degeneration as long as the Bcl-xL was present in the medium.

RNA interference targeting Akt promotes apoptosis in hypoxia-exposed human neuroblastoma cells.

Overactivation of the PI3 kinase/Akt pathway plays an essential role in the development and progression of various tumors. Akt is a key component of this pathway and hyperactivated in different tumors including neuroblastoma and glioma. In the present study, we tested the therapeutic efficacy of siRNA targeting Akt in inducing apoptotic cell death in NBFL cells (a human neuroblastoma cell line) subjected to anoxia/reoxygenation (A/R), a process that has been shown to modulate growth and progression of malignant tumors.

HIF-1alpha has an anti-apoptotic effect in human airway epithelium that is mediated via Mcl-1 gene expression.

Hypoxia-inducible factor-1alpha (HIF-1alpha) and myeloid cell leukemia-1 (Mcl-1) proteins have been shown to regulate apoptosis in some cell systems but have not been studied in this context in airway epithelium. Using a model of anoxia/reoxygenation (A/R), the present study employed RNA interference (RNAi) targeting HIF-1alpha and Mcl-1 to evaluate their possible anti-apoptotic effects on HBE1 cells, an immortalized human bronchial epithelial cell line. The cells were either cultured under normoxic conditions or were transfected with small interfering RNA (siRNA) duplexes targeting HIF-1alpha or Mcl-1 mRNA and then immediately exposed to A/R.

Antiapoptotic action of hypoxia-inducible factor-1 alpha in human endothelial cells.

Hypoxia-inducible factor-1 (HIF-1) is the major transcription factor involved in the adaptive response to hypoxia and consists of HIF-1 alpha and HIF-1 beta subunits. Indirect evidence suggests that HIF-1 alpha may exert both proapoptotic and antiapoptotic actions in response to hypoxia. In this study, we evaluated the effects of RNA interference (RNAi) targeting HIF-1 alpha messenger RNA (mRNA) on apoptosis in primary cultured human umbilical vascular endothelial cells (HUVECs) exposed to anoxia and reoxygenation (A/R).

Extracellular Bad fused to toxin transport domains induces apoptosis.

Bad, a proapoptotic member of the Bcl-2 family, is inactivated by phosphorylation, and this loss of activity may contribute to the malignancy of certain types of tumors such as glioblastoma and prostate cancer. To determine whether extracellular Bad can be delivered into cells via cell surface receptor binding and induce apoptosis, we genetically fused the mouse Bad gene to the gene for the translocation and receptor-binding domains of diphtheria toxin (DTTR). The purified Bad (wild-type)-DTTR protein showed cytotoxicity to human glioma cells in a dose-dependent manner.