[Corrigendum] BCL‑3 promotes the tumor growth of hepatocellular carcinoma by regulating cell proliferation and the cell cycle through cyclin D1

Subsequently to the publication of the above article, the authors have alerted the Editorial Office to the fact that they identified a small number of errors concerning the assembly of Figs. 3A, 6B and 7A in their paper. Specifically, the western blotting results for the BCL‑3 and GAPDH experiments in Fig. 3A, the cyclin D1 blots in Fig. 6B and the cyclin D1 blots shown in Fig. 7A were selected erroneously when choosing images from the total pool of data due to the similarity in the appearance of the data. However, the authors retained their access to the raw data, and were able to make the appropriate corrections required for these figures. The corrected versions of Figs. 3, 6 and 7, showing the correct BLC‑3/GAPDH and cyclin D1 data in Fig. 3A and 6B respectively, and the correct cyclin D1 data in Fig. 7A, are shown on the next two pages. Note that these errors did not adversely affect the major conclusions reported in the study. The authors all agree to the publication of this corrigendum, and thank the Editor of Oncology Reports for allowing them the opportunity to publish this. The authors also apologize for any inconvenience caused. [Oncology Reports 35: 2382‑2390, 2016; DOI: 10.3892/or.2016.4616].

BCL-3 and β-catenin signaling and tumor staging in colorectal cancer

Colorectal cancer (CBC) is the third most common cancer in men and the second most common cancer in women in the world, as well as the second leading cause of death among the world's cancers. In this study, to identify the genes involved in the CRC clinical outcomes, the expression of B cell leukemia/lymphoma 3 (BCL-3) gene in patients with colorectal cancer was investigated along with serum level of β-catenin. In this study, samples of 23 patients with colorectal cancer were prepared. mRNA was extracted and then cDNA was prepared for evaluation of PCR. Then, with specific primers for the BCL3, a semi-quantitative RT-PCR test was performed. The enzyme-linked immunosorbent assay (ELISA) was used to assess the serum level of β-catenin. In this study, 23 men with an average age of years were included. BCL-3 expression in tumor tissue was significantly higher than its level in healthy tissue (P=0.021). BCL-3 expression at stage 0 of the tumor was significantly lower than at all other stages (P<0.05), and the comparison between the rest of the CRC stages was not significant (P>0.05). The median of serum β-catenin levels in the patients was 32.83 (22.45, 46.09). There was no significant difference in the amount of serum β-catenin between all 5 stages of the disease and in terms of lymph node metastasis. There were no relationships between age, BMI, smoking history, familial CRC history, and BCL-3 or β-catenin serum levels (P>0.05). In this study, the expression of the BCL-3 gene in tumor specimens was high. It can be said that the BCL-3 gene can act as one of the genes involved in colorectal cancer, along with some genes such as β-catenin. While BCL-3 was associated with a higher stage of CRC, β-catenin didn't show such a relationship with CRC.

BCL‑3 promotes cyclooxygenase‑2/prostaglandin E2 signalling in colorectal cancer

First discovered as an oncogene in leukaemia, recent reports highlight an emerging role for the proto‑oncogene BCL‑3 in solid tumours. Importantly, BCL‑3 expression is upregulated in >30% of colorectal cancer cases and is reported to be associated with a poor prognosis. However, the mechanism by which BCL‑3 regulates tumorigenesis in the large intestine is yet to be fully elucidated. In the present study, it was shown for the first time that knocking down BCL‑3 expression suppressed cyclooxygenase‑2 (COX‑2)/prostaglandin E2 (PGE2) signalling in colorectal cancer cells, a pathway known to drive several of the hallmarks of cancer. RNAi‑mediated suppression of BCL‑3 expression decreased COX‑2 expression in colorectal cancer cells both at the mRNA and protein level. This reduction in COX‑2 expression resulted in a significant and functional reduction (30‑50%) in the quantity of pro‑tumorigenic PGE2 produced by the cancer cells, as shown by enzyme linked immunoassays and medium exchange experiments. In addition, inhibition of BCL‑3 expression also significantly suppressed cytokine‑induced (TNF‑α or IL‑1β) COX‑2 expression. Taken together, the results of the present study identified a novel role for BCL‑3 in colorectal cancer and suggested that expression of BCL‑3 may be a key determinant in the COX‑2‑meditated response to inflammatory cytokines in colorectal tumour cells. These results suggest that targeting BCL‑3 to suppress PGE2 synthesis may represent an alternative or complementary approach to using non‑steroidal anti‑inflammatory drugs [(NSAIDs), which inhibit cyclooxygenase activity and suppress the conversion of arachidonic acid to prostaglandin], for prevention and/or recurrence in PGE2‑driven tumorigenesis.

Low expression of IL-6 and TNF-α correlates with the presence of the nuclear regulators of NF-κB, IκBNS and BCL-3, in the uterus of mice

The dynamic regulation of NF-κB activity in the uterus maintains a favorable environment of cytokines necessary to prepare for pregnancy throughout the estrous cycle. Recently, the mechanisms that directly regulate the NF-κB transcriptional activity in different tissues are of growing interest. IκBNS and BCL-3 are negative nuclear regulators of NF-κB activity that regulate IL-6 and TNF-α transcription, respectively. Both cytokines have been described as important factors in the remodeling of uterus for blastocyst implantation. In this work we analyzed in ICR mice the mRNA expression and protein production profile of IL-6, TNF-α, and their correspondent negative transcription regulators IκBNS or BCL-3 using real-time PCR, western blot and immunochemistry. We found that the expression of TNF-α and IL-6 was oscillatory along the estrous cycle, and its low expression coincided with the presence of BCL-3 and IκBNS, and vice versa, when the presence of the regulators was subtle, the expression of TNF-α and IL-6 was exacerbated. When we compared the production of TNF-α and IL-6 in the different estrous stages relating with diestrus we found that at estrus there is an important increase of the cytokines (p<0.05) decreasing at metestrus to reach the basal expression at diestrus. In the immunochemistry analysis we found that at diestrus BCL-3 is distributed all over the tissue with a barely detected TNF-α, but on the contrary, at estrus the expression of BCL-3 is not detected with TNF-α clearly observable along the tissue; the same phenomenon occur in the analysis of IκBNS and IL-6. With that evidence we suggest that the expression of TNF-α and IL-6 might be regulated through NF-κB nuclear regulators BCL-3 and IκBNS in the uterus of mice as has been demonstrated in other systems.

Mapping the Interaction of B Cell Leukemia 3 (BCL-3) and Nuclear Factor κB (NF-κB) p50 Identifies a BCL-3-mimetic Anti-inflammatory Peptide

The NF-κB transcriptional response is tightly regulated by a number of processes including the phosphorylation, ubiquitination, and subsequent proteasomal degradation of NF-κB subunits. The IκB family protein BCL-3 stabilizes a NF-κB p50 homodimer·DNA complex through inhibition of p50 ubiquitination. This complex inhibits the binding of the transcriptionally active NF-κB subunits p65 and c-Rel on the promoters of NF-κB target genes and functions to suppress inflammatory gene expression. We have previously shown that the direct interaction between p50 and BCL-3 is required for BCL-3-mediated inhibition of pro-inflammatory gene expression. In this study we have used immobilized peptide array technology to define regions of BCl-3 that mediate interaction with p50 homodimers. Our data show that BCL-3 makes extensive contacts with p50 homodimers and in particular with ankyrin repeats (ANK) 1, 6, and 7, and the N-terminal region of Bcl-3. Using these data we have designed a BCL-3 mimetic peptide based on a region of the ANK1 of BCL-3 that interacts with p50 and shares low sequence similarity with other IκB proteins. When fused to a cargo carrying peptide sequence this BCL-3-derived peptide, but not a mutated peptide, inhibited Toll-like receptor-induced cytokine expression in vitro. The BCL-3 mimetic peptide was also effective in preventing inflammation in vivo in the carrageenan-induced paw edema mouse model. This study demonstrates that therapeutic strategies aimed at mimicking the functional activity of BCL-3 may be effective in the treatment of inflammatory disease.