Nuclear beta-catenin expression is rare and its potential association with short survival in colorectal signet-ring cell carcinoma

Long non-coding RNA CCAT2 promotes cell proliferation and invasion through regulating Wnt/β-catenin signaling pathway in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is a common urologic malignancy. Long non-coding RNA colon cancer-associated transcript 2 (CCAT2) has been suggested as serving pivotal roles in tumorigenesis. However, the clinical significance and biological role of CCAT2 in ccRCC remains elusive. The purpose of this study is to identify the function of CCAT2 in ccRCC and its possible molecular mechanism. Expression of CCAT2 was analyzed in 61 ccRCC tissues and two ccRCC cell lines (786-O and ACHN) by quantitative reverse transcription polymerase chain reaction. The functional roles of CCAT2 in ccRCC were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, colony formation assay, Transwell assay, and flow cytometric analysis. The influence of CCAT2 on tumorigenesis was monitored by in vivo mice xenograft model. The activation of Wnt/β-catenin signaling pathway was evaluated by the TOP/FOP Wnt luciferase reporter assay and western blot assay. CCAT2 expression was markedly higher in ccRCC cell lines and tissues, being positively associated with tumor size and tumor stage in ccRCC patients. Patients with higher CCAT2 expression had a markedly poorer overall survival than did patients with low CCAT2 expression. Knocking down CCAT2 expression led to reduced cell proliferation and increased apoptosis of ccRCC cells in vitro as well as the activation of Wnt/β-catenin signaling pathway, and CCAT2 overexpression remarkably enhanced these oncogenic properties. In vivo mice xenograft model also showed that knocking CCAT2 expression inhibited the growth of ccRCC xenografts. In conclusion, these results indicated that CCAT2 may play a critical role in ccRCC progression and will be further considered as a biomarker for predicting the survival of ccRCC patients and a potential therapeutic target for ccRCC intervention.

BHX Inhibits the Wnt Signaling Pathway by Suppressing β-catenin Transcription in the Nucleus

BHX (N-(4-hydroxybenzyl)-1,3,4-triphenyl-4,5-dihydro-1H-pyrazole-5-carboxamide), a Wnt signaling pathway inhibitor, effectively inhibits tumor cell growth, but the underlying mechanism is unclear. Thus, we aim to investigate the effects and associated mechanism of BHX action on A549 and MCF-7 cell lines. In our study, MTT(3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2H-tetrazolium bromide) and xenograft model assay indicated that cell growth was inhibited by BHX at a range of concentrations in vitro and in vivo. The expression of β-catenin and Wnt signaling pathway downstream target genes were decreased evidently under BHX treatment. Flow cytometry also revealed that BHX treatment significantly induced G1 arrest. Further analysis showed that BHX lowered the transcriptional level of β-catenin. In conclusion, BHX inhibited the nuclear synthesis of β-catenin, thereby suppressing the Wnt signaling pathway and further inhibiting tumor growth and proliferation.

Attenuation of chondrogenic transformation in vascular smooth muscle by dietary quercetin in the MGP-deficient mouse model

RATIONALE

Cartilaginous metaplasia of vascular smooth muscle (VSM) is characteristic for arterial calcification in diabetes and uremia and in the background of genetic alterations in matrix Gla protein (MGP). A better understanding of the molecular details of this process is critical for the development of novel therapeutic approaches to VSM transformation and arterial calcification.

OBJECTIVE

This study aimed to identify the effects of bioflavonoid quercetin on chondrogenic transformation and calcification of VSM in the MGP-null mouse model and upon TGF-β3 stimulation in vitro, and to characterize the associated alterations in cell signaling.

METHODS AND RESULTS

Molecular analysis revealed activation of β-catenin signaling in cartilaginous metaplasia in Mgp-/- aortae in vivo and during chondrogenic transformation of VSMCs in vitro. Quercetin intercepted chondrogenic transformation of VSM and blocked activation of β-catenin both in vivo and in vitro. Although dietary quercetin drastically attenuated calcifying cartilaginous metaplasia in Mgp-/- animals, approximately one-half of total vascular calcium mineral remained as depositions along elastic lamellae.

CONCLUSION

Quercetin is potent in preventing VSM chondrogenic transformation caused by diverse stimuli. Combined with the demonstrated efficiency of dietary quercetin in preventing ectopic chondrogenesis in the MGP-null vasculature, these findings indicate a potentially broad therapeutic applicability of this safe for human consumption bioflavonoid in the therapy of cardiovascular conditions linked to cartilaginous metaplasia of VSM. Elastocalcinosis is a major component of MGP-null vascular disease and is controlled by a mechanism different from chondrogenic transformation of VSM and not sensitive to quercetin.

Signet-ring cell carcinoma of colorectum--current perspectives and molecular biology

PURPOSE

Colorectal signet-ring cell carcinoma (SRCC) is rare, and very little detailed information on the molecular biology of the disease is available.

METHODS

The literature on the clinical, pathological and, in particular, the molecular biology of this rare entity was critically reviewed. The reviewed articles take into account a total of 1,817 cases of SRCC, but only 143 cases have molecular data available. The characteristics of two patients with colorectal SRCC were also discussed.

RESULTS

Colorectal SRCC mostly occurs in younger patients, is larger and has different site predilection compared with conventional colorectal adenocarcinoma. It can occur as one of the synchronous cancers in the colorectum. The cancer is usually diagnosed at advanced stages because of the late manifestation of symptoms, and aggressive treatment strategy is required. Limited reports in the literature have shown that the variant of colorectal cancer demonstrated a different pattern of genetic alterations of common growth kinase-related oncogenes (K-ras, BRAF), tumour suppressor genes (p53, p16), gene methylation and cell adhesion-related genes related to the Wingless signalling pathway (E-cadherin and beta-catenin) from conventional colorectal adenocarcinoma. Colorectal SRCC also showed high expression of mucin-related genes and genes related to the gastrointestinal system. There was also a higher prevalence of microsatellite instability-high tumours and low Cox-2 expression in colorectal SRCC as opposed to conventional adenocarcinoma.

CONCLUSIONS

Colorectal SRCC has unique molecular pathological features. The unique molecular profiles in SRCC may provide molecular-based improvements to patient management in colorectal SRCC.

HNPCC-associated synchronous early-stage signet-ring cell carcinomas of colonic origin. A comparative morphological and immunohistochemical study of an intramucosal and a submucosal example

Signet-ring cell carcinoma (SRCC) developing in the colorectum (CR) is infrequently identified at an early stage (no deeper than submucosa). Most such examples involve the submucosa. Merely 13 cases of intramucosal CR SRCC are at hand. We recently had the opportunity to study a specimen with two synchronous early-stage SRCC, developed in a 65-year-old hereditary nonpolyposis colorectal cancer male patient with a known disease-causing mutation in MLH1. A right hemicolectomy specimen comprised a 15-mm intramucosal cecal lesion, featuring zones of conventional tubular adenoma and intraepithelial SRCC as well as tumor cells multifocally permeating the lamina propria and a 12-mm submucosally expanding SRCC of the ascending colon. The intramucosal and intraepithelial as well as stromal lesional cells displayed a normal membranous expression of beta-catenin and E-cadherin; submucosally infiltrating cells featured alterations in this complex with loss of membranous expression of both proteins and a shift with nuclear accumulation of beta-catenin, suggesting a disruption of the Wingless signaling pathway taking place at the transition from the intramucosal to the submucosal level.