Protein kinase C alpha mRNA 3'-untranslated region (PRKCA mRNA 3'-UTR)

The 3'-untranslated region (3'-UTR) of the Protein kinase C alpha (PKC-alpha) mRNA is a regulatory sequence targeted by antisense therapies to modulate the expression of the PKC-alpha protein (Dean et al., 1994). PKC-alpha is a member of the serine/threonine protein kinase family and plays a pivotal role in signal transduction pathways related to cell proliferation, apoptosis, and differentiation (UniProt P17252). Overexpression of PKC-alpha has been implicated in the pathogenesis of several cancers, including non-small cell lung cancer and breast cancer, where it promotes tumor cell survival and invasion (Yuen and Modjtahedi, 2004). The drug aprinocarsen (ISIS 3521) was specifically designed as a phosphorothioate antisense oligonucleotide to bind to a 20-nucleotide sequence within this 3'-UTR, triggering RNase H-mediated cleavage of the mRNA (Holmlund et al., 1999). This reduction in mRNA levels leads to a subsequent decrease in PKC-alpha protein synthesis, theoretically inhibiting tumor growth. Despite showing activity in Phase I and II trials, aprinocarsen failed to meet primary endpoints in Phase III clinical trials for lung cancer, leading to a halt in its development (Lahn et al., 2004). The 3'-UTR is particularly significant because it contains elements that regulate mRNA stability and translation efficiency, making it a strategic site for antisense intervention. Therapeutic challenges include the delivery of oligonucleotides to tumor tissues and the potential for off-target effects or compensatory signaling by other PKC isoforms.

Other names

PKC-alpha mRNAPRKCA mRNA3'-UTR of PKC-alphaISIS 3521 target siteAffinitak target

Antisense oligonucleotide-mediated degradation of mRNA via RNase H activation, leading to downregulation of Protein kinase C alpha protein expression (Dean et al., 1994; Holmlund et al., 1999).