Ribozyme-Mediated Targeting of IκBγ Inhibits Melanoma Invasion and Metastasis

Abstract

IkappaBgamma is one member of a family of proteins that can inhibit the nuclear localization of nuclear factor-kappaB. However, the other specific functions of IkappaBgamma are still poorly understood, and its effects on tumor metastasis have not yet been characterized. We examined the consequences of targeting IkappaBgamma in melanoma cells using a hammerhead ribozyme. We developed stable transformant B16-F10 melanoma cell lines that express a ribozyme that targets mouse IkappaBgamma (IkappaBgamma-144-Rz). Tail-vein injection of B16-F10 cells that stably express IkappaBgamma-144-Rz into mice resulted in a significant reduction of the metastatic potential of these cells. IkappaBgamma-144-Rz-expressing B16 cells were shown to have increased transcriptional activity of nuclear factor-kappaB. We then showed that IkappaBgamma-144-Rz-expressing cells demonstrated both reduced invasion and increased apoptosis, suggesting the existence of pathways through which IkappaBgamma promotes melanoma metastasis. Using gene expression profiling, we identified a differentially expressed gene set that is regulated by the stable suppression of IkappaBgamma that may participate in mediating its anti-metastatic effects; we also confirmed the altered expression levels of several of these genes by quantitative real time polymerase chain reaction. Plasmid-mediated expression of IkappaBgamma-144-Rz produced a significant inhibition of the metastatic progression of B16-F10 cells to the lung and resulted in significant anti-invasive and pro-apoptotic effects on murine Lewis lung carcinoma cells. Our results suggest a novel role for IkappaBgamma in promoting the metastatic progression of melanoma.

Epigenetic Regulation of KPC1 Ubiquitin Ligase Affects the NF-κB Pathway in Melanoma

“…The importance of the miR-155-5p-KPC1-NF-κB-axis in melanoma suggested new prospects in melanoma therapy. Abnormal activation of the NF-κB pathway switches non-aggressive melanoma to an aggressive phenotype (7–11), thus, inhibiting NF-κB pathway activation holds therapeutic promise for cutaneous melanoma. Inhibitors that directly target NF-κB pathway, such as IKKβ inhibitors, have been developed; however these drugs also exert NF-κB-independent effects, leading to high risk of side effects and toxicity (12,39–41).…”

“…Despite recent advances in molecular targeted therapies and immunotherapies, the long-term survival of these patients remains poor, particularly in metastatic melanoma (3–6). One of the mechanisms that switch non-aggressive melanoma to an aggressive phenotype is dysregulation in the nuclear factor-κB (NF-κB) pathway (7–11). NF-κB is a key transcription factor regulating the expression of multiple genes involved in various cellular functions, such as immune or inflammatory responses, cell proliferation, differentiation, and progression of multiple tumor types (7,8,12–14).…”

“…NF-κB is a key transcription factor regulating the expression of multiple genes involved in various cellular functions, such as immune or inflammatory responses, cell proliferation, differentiation, and progression of multiple tumor types (7,8,12–14). In melanoma, up-regulation of the NF-κB pathway is correlated with melanoma progression through suppression of the apoptosis and promotion of metastasis (7–11). Furthermore, there are autocrine mechanisms promoting constitutive activation of the NF-κB pathway in melanoma cells (7,8).…”

Therapeutic microRNAs targeting the NF-kappa B signaling circuits of cancers

“…In cutaneous melanoma cells, as well as in ovarian cancer [144], miR-9 binds directly to the NF-κB1 (p105) 3′-UTR, and down-regulates the expression of NF-κB1. The activity of NF-κB1 is known to be critical in the induction of cytoskeletal reorganization, which is important in cell metastasis [145, 146]. In melanoma cells, it has been further shown that the overexpression of miR-9 and down-regulation of NF-κB1 and Snail1 pathways lead to the inhibition of the expression of cytoskeleton proteins including Rab8, p65, MMP-2, and MMP-9.…”

Lung tumor NF-κB signaling promotes T cell–mediated immune surveillance

“…or s.c.). Tumor volume was calculated as previously described (82). Relative tumor growth between treatment groups was analyzed using the t test with Welch's correction.…”