Alpha-methylacyl-CoA racemase/P504S overexpression in colorectal carcinoma is correlated with tumor differentiation

LIN28B induces a differentiation program through CDX2 in colon cancer

Most colorectal cancers (CRCs) are moderately differentiated or well differentiated, a status that is preserved even in metastatic tumors. However, the molecular mechanisms underlying CRC differentiation remain to be elucidated. Herein, we unravel a potentially novel posttranscriptional regulatory mechanism via a LIN28B/CDX2 signaling axis that plays a critical role in mediating CRC differentiation. Owing to a large number of mRNA targets, the mRNA-binding protein LIN28B has diverse functions in development, metabolism, tissue regeneration, and tumorigenesis. Our RNA-binding protein IP (RIP) assay revealed that LIN28B directly binds CDX2 mRNA, which is a pivotal homeobox transcription factor in normal intestinal epithelial cell identity and differentiation. Furthermore, LIN28B overexpression resulted in enhanced CDX2 expression to promote differentiation in subcutaneous xenograft tumors generated from CRC cells and metastatic tumor colonization through mesenchymal-epithelial transition in CRC liver metastasis mouse models. A ChIP sequence for CDX2 identified α-methylacyl-CoA racemase (AMACR) as a potentially novel transcriptional target of CDX2 in the context of LIN28B overexpression. We also found that AMACR enhanced intestinal alkaline phosphatase activity, which is known as a key component of intestinal differentiation, through the upregulation of butyric acid. Overall, we demonstrated that LIN28B promotes CRC differentiation through the CDX2/AMACR axis.

Effect of long non-coding RNA Gas5 on proliferation, migration, invasion and apoptosis of colorectal cancer HT-29 cell line

Objective

This study aims to investigate the effect of long non-coding RNA (lncRNA) Gas5 on proliferation, migration, invasion and apoptosis of colorectal cancer (CRC) HT-29 cell line.

Methods

CRC and normal tissues were collected and prepared from a total of 126 CRC patients, and normal intestinal epithelial cell line FHC and CRC cell lines (HCT-8, HT-29, HCT-116 and SW-480) were prepared. Gas5 expression was detected by quantitative reverse transcriptase-polymerase chain reaction. HT-29 cell line exhibiting the lowest Gas5 expression was selected for further experimentation and divided into blank, negative control and pcNDA-Gas5 groups. The cell counting kit-8 assay was used to test cell proliferation. Flow cytometry was applied to examine cell apoptosis. Transwell assay was performed to detect the migration and invasion of HT-29 cells. The mRNA and protein expression of factors in the classical proliferation (Akt/Erk) and apoptosis (caspase-9/caspase-3) pathways were detected.

Results

Gas5 expression was lower in CRC tissues compared to the adjacent normal tissues, and is also lower in CRC cell lines than FHC cell line. Gas5 expression was associated with tumor size and TNM staging. Gas5 expression, distant metastasis, tumor differentiation and TNM staging were independent CRC prognostic factors. The results showed that elevated Gas5 expression inhibited proliferation, migration and invasion, but promoted apoptosis of CRC cells. Meanwhile, elevated Gas5 expression inhibited mRNA expression of Akt and Erk and protein expression of p-Akt and p-Erk, which promoted Casp9 mRNA and pho-Casp9 protein expression but inhibited Casp3 mRNA and pho-Casp3 protein expression.

Conclusion

The findings indicated that overexpression of lncRNA Gas5 can inhibit the proliferation, migration and invasion but promote apoptosis of CRC cells.

Expression of Alpha - Methylacyl - Coenzyme A Racemase (AMACR) in Colorectal Neoplasia

INTRODUCTION

Red meat and dairy products have been implicated in colonic cancers. They are rich in branched chain fatty acids which require an enzyme Alpha-Methylacyl-Coenzyme A Racemase (AMACR) for their oxidation. Increased expression of AMACR in colorectal premalignant lesions and carcinomas suggests its possible role in carcinogenesis.

AIM

To study the expression of AMACR in colorectal neoplasia and its correlation with the histological grade, stage and nodal status of colorectal malignancy.

MATERIALS AND METHODS

All cases of colorectal neoplasms were included in the study. AMACR expression was studied in 56 cases which included 44 cases of adenocarcinoma and 12 cases of adenoma and a normal colonic mucosal tissue was used as a control. A tissue microarray was prepared by manual method. AMACR expression was studied by Immunohistochemistry (IHC) and it was correlated with the grade, stage and nodal status of the cancer. Chi-square test was used for analysis or results. The p-value of <0.05 was considered significant.

RESULTS

Out of 12 cases of adenoma 25% (3/12) were negative; 50% (6/12) showed poor expression, 25% (3/12) had moderate expression and none showed strong expression. Nearly, 34.1% (15/44) case of carcinoma were negative; 45.45% (20/44) had poor; 13.63% (6/44) had moderate and 6.81% (3/44) had a strong expression. Normal colonic tissue showed no expression. There was no significant difference of AMACR expression between adenoma and carcinoma cases. AMACR expression was found to be increased in low grade carcinomas (G1 and G2). G1 showed AMACR positivity in 62% cases and G2 showed 71.4% positivity. No association was found between AMACR expression and different American Joint Committee on Cancer (AJCC) stages and nodal status of CRC.

CONCLUSION

Increased expression of AMACR in adenomas and carcinomas as compared to non-neoplastic epithelium of colon implies that, it plays a role in colorectal neoplasia. Decreased expression of AMACR in high grade carcinomas suggests its role in differentiation of the tumour.

α-Methylacyl-CoA racemase (AMACR) in gastric cancer: correlation with clinicopathologic data and disease-free survival

Diagnostic and prognostic significance of α-methylacyl-CoA racemase (AMACR) has been established in many human cancers. Its correlation with clinical and pathologic data in gastric cancer has not been fully elucidated and its impact on surveillance has not been studied thus far. We analyzed consecutive gastric cancer cases in terms of AMACR expression and clinical/pathologic characteristics and followed patients' postoperative history. AMACR was expressed in 94/164 gastric cancers (57.3%). We did not find correlation between AMACR expression and sex, age, location, histologic type, pTN staging, vascular and nerve sheaths invasion. Overall disease-free survival tended to be worse in AMACR-positive patients (P=0.062), and in adenocarcinoma subgroup, it was significantly shorter (P=0.021). AMACR expression might represent promising adverse prognostic factor in gastric cancer, particularly in adenocarcinoma histologic type.

Interpretation of needle biopsies of the kidney for investigation of renal masses

The development of new therapeutic options for renal tumors has lead to the need of a pretherapeutic diagnosis for an increasing proportion of patients presenting with a renal mass. This need is particularly important for a small, incidentally discovered renal mass (less than 4 cm) as it can be a benign lesion in a significant percentage of cases. Recent studies have shown that needle biopsy is an accurate and safe method allowing for a precise histopathological diagnosis of the mass in most cases. The aims of the biopsy are (1) to assess the benign or malignant nature of the lesion, (2) to assess the primary or secondary nature of the lesion, and (3), in case of a primary malignancy, to determine histological prognostic factors, such as the tumor type. This review, based on the most recent literature and our own experience, is intended to provide a practical approach to the diagnosis, relying on appropriate morphologic assessment and the use of immunohistochemistry.

AMACR is associated with advanced pathologic risk factors in sporadic colorectal adenomas

AIM: To analyze α-methylacyl CoA racemase (AMACR) expression in relation to various dysplasia phenotypes and clinicopathological parameters of sporadic colorectal adenomas.

METHODS: Fifty-five cases of sporadic colorectal adenomas were categorized according to the Vienna classification for Gastrointestinal Neoplasia. These corresponded to a total of 98 different intra-lesion microscopic fields that were further independently assigned a histological grade based on the old nomenclature (mild, moderate, severe dyplasia and carcinoma in situ). AMACR expression was evaluated by immunohistochemistry and statistical analysis was performed to investigate possible associations with various clinicopathologic parameters of adenomas i.e. gender, age, localization, grade of dysplasia, size and configuration.

RESULTS: Patient age ranged from 41 to 84 years (mean 65 ± 13.2 years); 37 patients were males and 18 were females. Adenomas ranged in size between 0.5 and 30 cm (mean 2 ± 1.3 cm), including 18 tubular, 16 villous, 20 mixed or tubulovillous, and 1 giant sessile villous adenoma. AMACR expression was observed in 3 out of 16 (18.8%) of low-grade vs 23 out of 35 (62.8%) of high-grade lesions (P = 0.002). Most adenomas exhibiting high grade dysplasia with in situ carcinoma-like areas stained positive for AMACR (15/17 or 88.2%) as compared to adenomas with high grade dysplasia which contained severe dysplasia-like foci (6/15 or 40%), (P = 0.005). In AMACR positive adenomas featuring severe dysplasia-like or in situ carcinoma-like areas, AMACR staining was not necessarily observed in the in situ component. Positivity in intra-lesion of mild, moderate or severe dysplasia-like foci was more often encountered in adenomas harboring in situ, intramucosal or infiltrative carcinoma [21/33 (63.6%) vs 9/40 (22.5%), P < 0.001]. Strong AMACR expression was found in 11 out of 17 villous adenomas, but in only 1 out of 18 tubular lesions (P = 0.005). Larger lesions, i.e. > 1 cm stained more frequently for AMACR than smaller ones [27/45 (60%) vs 2/10 (20%), P = 0.02]. Overall, AMACR expression was associated with the grade of dysplasia, as well as with the size and configuration of adenomas, i.e. the consensus risk factors applied to colorectal adenoma patient surveillance.

CONCLUSION: It may be worthy to further evaluate the possible use of AMACR as an additional risk factor for the assessment of colorectal adenoma patients.

Deletion hotspots in AMACR promoter CpG island are cis-regulatory elements controlling the gene expression in the colon

Alpha-methylacyl-coenzyme A racemase (AMACR) regulates peroxisomal beta-oxidation of phytol-derived, branched-chain fatty acids from red meat and dairy products -- suspected risk factors for colon carcinoma (CCa). AMACR was first found overexpressed in prostate cancer but not in benign glands and is now an established diagnostic marker for prostate cancer. Aberrant expression of AMACR was recently reported in Cca; however, little is known about how this gene is abnormally activated in cancer. By using a panel of immunostained-laser-capture-microdissected clinical samples comprising the entire colon adenoma-carcinoma sequence, we show that deregulation of AMACR during colon carcinogenesis involves two nonrandom events, resulting in the mutually exclusive existence of double-deletion at CG3 and CG10 and deletion of CG12-16 in a newly identified CpG island within the core promoter of AMACR. The double-deletion at CG3 and CG10 was found to be a somatic lesion. It existed in histologically normal colonic glands and tubular adenomas with low AMACR expression and was absent in villous adenomas and all CCas expressing variable levels of AMACR. In contrast, deletion of CG12-16 was shown to be a constitutional allele with a frequency of 43% in a general population. Its prevalence reached 89% in moderately differentiated CCas strongly expressing AMACR but only existed at 14% in poorly differentiated CCas expressing little or no AMACR. The DNA sequences housing these deletions were found to be putative cis-regulatory elements for Sp1 at CG3 and CG10, and ZNF202 at CG12-16. Chromatin immunoprecipitation, siRNA knockdown, gel shift assay, ectopic expression, and promoter analyses supported the regulation by Sp1 and ZNF202 of AMACR gene expression in an opposite manner. Our findings identified key in vivo events and novel transcription factors responsible for AMACR regulation in CCas and suggested these AMACR deletions may have diagnostic/prognostic value for colon carcinogenesis.

AMACR expression in colorectal cancer is associated with left-sided tumor localization

Alpha-methylacyl-CoA racemase (AMACR) is an enzyme playing an important role in the beta-oxidation of branched-chain fatty acids and fatty acid derivatives. Altered expression levels of AMACR have been described in various cancers including colorectal cancer (CRC). To determine the potential prognostic impact of AMACR expression, we analyzed 1,315 CRC on a tissue microarray (TMA) by immunohistochemistry (IHC). Clinical follow-up data were available from all cancer patients. Positive AMACR staining was observed in 1,074 (81.7%) of the 1,315 cases including 276 cancers with weak (21.0%) and 798 cancers with strong staining (60.7%). AMACR IHC was significantly associated with tumor grade, stage, non-mucinous phenotype, and left-sided tumor localization (p < 0.0001 each). AMACR positivity was observed in 65.8% of cancers from the right-sided colon, in 73.2% of cancers from the colon transversum, in 81.1% of cancers from the colon descendens, and in 88.9% of the distal left-sided cancers (sigma and rectum; p < 0.0001). However, AMACR staining results were unrelated to clinical outcome. It is concluded that AMACR cannot serve as a prognostic marker in CRC. We hypothesize that the association of AMACR expression with tumor localization may be related to differences in the metabolism/exposure to fatty acids occurring along the colon.