Evidence That Calebin A, a Component of Curcuma Longa Suppresses NF-κB Mediated Proliferation, Invasion and Metastasis of Human Colorectal Cancer Induced by TNF-β (Lymphotoxin)

Abstract

Objective: Natural polyphenol Calebin A has been recently discovered as a novel derivate from turmeric with anti-cancer potential. Pro-inflammatory cytokine TNF-β (lymphotoxin α) is a stimulant for cancer cell malignity via activation of NF-κB pathway, also in colorectal cancer (CRC). Here, we investigated the potential of Calebin A to suppress TNF-β-induced NF-κB signalling in CRC. Materials and Methods: Three distinct CRC cell lines (HCT116, RKO, SW480) were treated in monolayer or 3-dimensional alginate culture with TNF-β, Calebin A, curcumin, BMS-345541, dithiothreitol (DTT) or antisense oligonucleotides-(ASO) against NF-κB. Results: Calebin A suppressed dose-dependent TNF-β-induced CRC cell vitality and proliferation in monolayer culture. Further, in alginate culture, Calebin A significantly suppressed TNF-β-enhanced colonosphere development, as well as invasion and colony formation of all three CRC cell lines investigated. Calebin A specifically blocked TNF-β-induced activation and nuclear translocation of p65-NF-κB, similar to curcumin (natural NF-κB inhibitor), BMS-345541 (specific IKK inhibitor) and ASO-NF-κB. Moreover, Immunofluorescence and Immunoblotting showed that Calebin A, similar to curcumin or BMS-345541 suppressed TNF-β-induced activation and nuclear translocation of p65-NF-κB and the transcription of NF-κB-promoted biomarkers associated with proliferation, migration and apoptosis, in a doseand time-dependent manner. Those findings were potentiated by the specific treatment of extracted nuclei with DTT, which abrogated Calebin A-mediated nuclear p65-NF-κB-inhibition and restored p65-NF-κB-activity in the nucleus. Conclusion: Overall, these results demonstrate, for the first time, that multitargeted Calebin A has an anti-cancer capability on TNF-β-induced malignities through inhibitory targeting of NF-κB activation in the cytoplasm, as well as by suppressing the binding of p65-NF-κB to DNA.

Calebin A Potentiates the Effect of 5-FU and TNF-β (Lymphotoxin α) against Human Colorectal Cancer Cells: Potential Role of NF-κB

“…We have previously demonstrated that TNF-β/NF-κB-induced CRC proliferation, chemoresistance and tumor stem cell promotion was suppressed by natural substances such as resveratrol [16,17]. Furthermore, in a previous study on CRC, we showed the potential of Calebin A on suppressing-TNF-β-induced inflammatory signaling, blocking proliferation, migration and invasion of CRC cells [18], emphasizing the promising of natural substances on targeting TNF-β/NF-κB signaling axis.…”

“…To prevent treatment failure, co-treatment with non-toxic dietary natural anti-cancer agents that possess the capacity to chemosensitize and treat these resistant tumors have great potential [39]. Calebin A, a naturally occurring compound (an ingredient of natural turmeric) has been suggested to have anti-cancer capacity in various solid cancer cells [18,[28][29][30].…”

“…Chronic intestinal inflammation is described to regulate expression and interaction of members of the TNF family such as TNF-α, TNF-β and LTβR acting as major mediators for CRC-related inflammation [44,45]. Moreover, our group has previously shown that TNF-β induces cancer progression and thus stimulates colorectal cancer cell malignity with the same potency as TNF-α [16,18,46]. Further, TNF-β, produced by tumor-associated lymphocytes in the tumor environment, has been shown to promote angiogenesis by signaling through the canonical NF-κB pathway [47], and in Hodgkin lymphoma, autocrine signaling of TNF-β has been described to drive disease progression by sustaining NF-κB activation [46].…”

“…Pro-inflammatory cytokines belonging to the Tumor Necrosis Factor family, such as TNF-α and TNF-β, play a key role in chronic diseases such as cancer [13]. TNF-β, the closest structural homolog to TNF-α, was identified around 35 years ago [14,15] and has recently come to attention as it may stimulate NF-κB activation in cancer cells with a similar potency to TNF-α, thereby up-regulating proliferation, invasion and malignancy of cancer cells [16][17][18].…”

“…In the past, the majority of investigations on the field of turmeric were focused primarily on its major polyphenolic ingredient curcumin [27]. However, recently attention has come to Calebin A, another type of turmeric rhizome pharmacologically active component [18,25,28]. The active compound Calebin A is an ingredient isolated from curcumin-free turmeric extract and has been reported to present anti-tumor qualities by targeting and suppression of a variety of molecular signaling pathways including the NF-κB pathway [18,[28][29][30].…”