Cyclin D1 polymorphism and expression in patients with squamous cell carcinoma of the head and neck

Aberrant Cyclin D1 splicing in cancer: from molecular mechanism to therapeutic modulation

Cyclin D1 (CCND1), a crucial mediator of cell cycle progression, possesses many mutation types with different mutation frequencies in human cancers. The G870A mutation is the most common mutation in CCND1, which produces two isoforms: full-length CCND1a and divergent C-terminal CCND1b. The dysregulation of the CCND1 isoforms is associated with multiple human cancers. Exploring the molecular mechanism of CCND1 isoforms has offer new insight for cancer treatment. On this basis, the alterations of CCND1 gene are described, including amplification, overexpression, and mutation, especially the G870A mutation. Subsequently, we review the characteristics of CCND1 isoforms caused by G870A mutation. Additionally, we summarize cis-regulatory elements, trans-acting factors, and the splice mutation involved in splicing regulation of CCND1. Furthermore, we highlight the function of CCND1 isoforms in cell cycle, invasion, and metastasis in cancers. Importantly, the clinical role of CCND1 isoforms is also discussed, particularly concerning prognosis, chemotherapy, and radiotherapy. Last, emphasis is given to the corrective strategies that modulate the cancerous CCND1 isoforms. Thus, it is highlighting significance of aberrant isoforms of CCND1 as targets for cancer therapy.

Gene polymorphisms and prognosis of head and neck squamous cell carcinoma: a systematic review

Background

Head and neck squamous cell carcinomas (HNSCCs) are associated with variable prognosis even with similar clinical characteristics and treatments. Gene polymorphisms have been suggested as prognostic factors for HNSCC which can justified this variable prognosis. So, the aim was to review literatures on gene polymorphisms and prognosis of HNSCCs.

Materials and methods

A systematic search was conducted using PubMed, Web of science, SCOPUS, Google Scholar and Cochrane library databases to find all related articles published up to December 2021 in the field of gene polymorphisms and HNSCC prognosis.

Results

Of 1029 initial searched articles, 71 articles were selected for inclusion in this systematic review. About 93 genes and 204 polymorphisms have been discussed in these articles. Among the most studied polymorphisms, the XRCC1 Arg399Gln and Arg194Trp polymorphisms were not associated with survival in most studies; the ERCC1 C19007T polymorphism had no significant association in any of the studies. Different gene polymorphisms of glutathione s-transferase family, including GSTM1 deletion, GSTT1 deletion and GSTP1 A313G, were not associated with survival in included studies. There are conflicting results regarding the association between polymorphisms such as ERCC2 A35931C, Asp312Asn, ERCC5 rs1047768 and rs17655 with HNSCC prognosis. Less studied polymorphisms, such as hOGG1 rs1052133 or the VEGF rs699947, were generally not associated with HNSCC prognosis.

Conclusion

Reviewed articles reported varied and contradictory results regarding the association of gene polymorphisms and HNSCC prognosis, which necessitates further studies along with meta-analysis on the results of such studies.

Cell Cycle Regulation by Alternative Polyadenylation of CCND1

Global shortening of 3′UTRs by alternative polyadenylation (APA) has been observed in cancer cells. However, the role of APA in cancer remains unknown. CCND1 is a proto-oncogene that regulates progression through the G1-S phase of the cell cycle; moreover, it has been observed to be switching to proximal APA sites in cancer cells. To investigate the biological function of the APA of CCND1, we edited the weak poly(A) signal (PAS) of the proximal APA site to a canonical PAS using the CRISPR/Cas9 method, which can force the cells to use a proximal APA site. Cell cycle profiling and proliferation assays revealed that the proximal APA sites of CCND1 accelerated the cell cycle and promoted cell proliferation, but UTR-APA and CR-APA act via different molecular mechanisms. These results indicate that PAS editing with CRISPR/Cas9 provides a good method by which to study the biological function of APA.

Anti-oncogenic activities of cyclin D1b siRNA on human bladder cancer cells via induction of apoptosis and suppression of cancer cell stemness and invasiveness

The human cyclin D1 gene generates two major isoforms, cyclin D1a and cyclin D1b, by alternative splicing. Although cyclin D1b mRNA is hardly expressed in normal human tissues, it is detected in approximately 60% of human bladder cancer tissues and cell lines. In the present study, to assess the therapeutic ability of cyclin D1b siRNA, we investigated the anti-oncogenic effects of cyclin D1b siRNA on human bladder cancer cell lines, SBT31A and T24, which express cyclin D1b mRNA. Knockdown of cyclin D1b by specific siRNA significantly suppressed cell proliferation, in vitro cell invasiveness and three-dimensional (3D) spheroid formation in these cell lines. Cell cycle analyses revealed that cyclin D1b siRNA inhibited G1-S transition in T24 cells. The increase in the sub-G1 fraction, morphological aberrant nuclei with nuclear fragmentation and caspase-3 activity in SBA31A cells treated with cyclin D1b siRNA showed that cyclin D1b siRNA induced apoptosis. In T24 cells, knockdown of cyclin D1b suppressed the expression of the stem cell marker CD44. Knockdown of cyclin D1b or CD44 suppressed the invasiveness under 3D spheroid culture conditions and expression of N-cadherin. Tumor growth of SBT31A cells in nude mice was significantly inhibited by cyclin D1b siRNA. Taken together, these results indicate that knockdown of cyclin D1b suppresses the malignant phenotypes of human bladder cancer cells via induction of apoptosis and suppression of cancer cell stemness and epithelial-mesenchymal transition. Applying cyclin D1b siRNA will be a novel therapy for cyclin D1b-expressing bladder cancers.

Akt-dependent activation of Erk by cyclin D1b contributes to cell invasiveness and tumorigenicity

A total of two major isoforms, cyclin D1a and cyclin D1b, are generated from the human cyclin D1 gene by alternative splicing. Cyclin D1b is scarcely expressed in normal tissues; however, it is expressed at a high frequency in certain types of cancerous tissue. The present authors previously constructed cyclin D1b transgenic (Tg) mice and identified rectal tumors, including adenocarcinoma and sessile serrated adenoma, in 62.5% of female Tg mice. In addition, the present authors indicated that cyclin D1b expression enhances phosphorylation of extracellular signal-regulated kinase (Erk) in these rectal tumors, and in mouse embryonic fibroblast (MEF) cells and human 293T cells. In the present study, it was initially demonstrated that cyclin D1b has the ability to enhance cell invasiveness by itself; it additionally increases cell invasiveness, anchorage-independent growth and tumorigenicity in cooperation with an activated K-ras oncogene in MEF cells. Phosphorylation of Akt was increased in cyclin D1b-expressing MEF cells and in the rectal tumor tissues of cyclin D1b Tg mice. Phosphorylation of Akt was also enhanced by transfection of cyclin D1b, but not cyclin D1a, in human 293T cells. Treatment with an Akt inhibitor suppressed phosphorylation of Erk in 293T cells expressing cyclin D1b and D1bTgRT cells established from rectal cancer of the cyclin D1b Tg mouse. Furthermore, the Akt inhibitor suppressed the invasiveness of D1bTgRT cells and the tumor growth of these cells in nude mice when the Akt inhibitor was injected into the tumors. These results indicate that cyclin D1b activates Erk through Akt, and that activation of Akt contributes to the tumorigenicity of the cyclin D1b Tg mice. Inhibitors targeting the phosphoinositide 3-kinase/Akt signaling pathway are thus expected to have therapeutic potential in a variety of human cancer types expressing cyclin D1b.

Association between the Cyclin D1 G870A polymorphism and the susceptibility to and prognosis of upper aerodigestive tract squamous cell carcinomas: an updated meta-analysis

PURPOSE

Several publications have investigated the association between the Cyclin D1 G to A substitution at nucleotide 870 (CCND1 G870A) polymorphism and squamous cell carcinoma (SCC) of the upper aerodigestive tract (UADT), but their conclusions still remain controversial. We conducted a meta-analysis to precisely evaluate this association.

PATIENTS AND METHODS

We electronically searched the Chinese National Knowledge Infrastructure, PubMed, and Embase (up to January 2015) databases for case-control studies on the association between the CCND1 G870A polymorphism and SCC of the UADT, and 23 studies were included in total.

RESULTS

The meta-analysis results showed that there was a significant association between the CCND1 G870A polymorphism and the risk of SCC of the UADT (AA vs GG: odds ratio [OR] =1.33, 95% confidence interval [CI] =1.01-1.74, P<0.001 for heterogeneity; GA/AA vs GG: OR =1.24, 95% CI =1.01-1.51, P<0.001 for heterogeneity; AA vs

GA/GG

OR =1.16, 95% CI =0.97-1.39, P<0.001 for heterogeneity; allele A vs allele G: OR =1.14, 95% CI =1.00-1.30, P<0.001 for heterogeneity; GA vs GG: OR =1.18, 95% CI =0.98-1.42, P<0.001 for heterogeneity). However, when analyzing prognosis, allele G was a potential risk factor for poor tumor differentiation (AA vs

GA/GG

OR =2.60, 95% CI =1.15-5.86, P=0.836 for heterogeneity) and reduced disease-free intervals (OR =2.08, 95% CI =1.17-3.69, P=0.134 for heterogeneity). In the subgroup analysis, the cancer susceptibility of Asian groups, population-based control groups, nasopharyngeal cancer groups, and esophageal SCC groups were more likely to be affected by the CCND1 G870A polymorphism. No significant publication bias was found in our analysis (P=0.961 for Egger's test and P=0.245 for Begg's test).

CONCLUSION

The results of the present meta-analysis suggest that the variant CCND1 870A allele might confer an elevated risk of SCC of the UADT, particularly among Asians and individuals who have esophageal or nasopharyngeal cancers. Moreover, the CCND1 870A allele might also confer better tumor differentiation grades and longer disease-free intervals.

Cyclin D1 G870A polymorphism and the risk of hepatocellular carcinoma in a Chinese population

Cyclin D1, encoded by the gene CCND1, is a regulatory protein in the cell cycle transition from G1 phase to S phase. A common polymorphism (G870A) in the exon 4 of CCND1 gene affects splicing of the CCND1 transcript and may cause uncontrollable cellular growth. Therefore, the CCND1 G870A polymorphism may influence an individual's susceptibility to the development of certain tumors. The present study was performed to test the association between G870A polymorphism in the CCND1 gene and hepatocellular carcinoma (HCC) risk in a Chinese population. We extracted the peripheral blood samples from 220 patients with HCC and 220 age- and gender-matched healthy controls. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis and direct DNA sequencing were performed to detect the polymorphism. The CCND1 genotype distribution among HCC patients was not significantly different from that among healthy controls (P=0.08). Compared with the wild-type GG genotype, neither the variant AA genotype nor the variant genotypes containing the A allele were associated with risk of HCC. However, stratification analysis by HBV carrier status revealed that the variant genotypes containing the A allele were associated with a significantly increased risk of HCC among HBsAg-positive individuals (adjusted OR=3.87; 95 % CI=1.12, 13.30). These results suggest that the CCND1 G870A polymorphism may increase the risk of HBV-related HCC in the Chinese population.

Female-specific rectal carcinogenesis in cyclin D1b transgenic mice

Human cyclin D1 generates two major isoforms via alternative splicing: cyclin D1a and cyclin D1b. Cyclin D1b is hardly expressed in normal tissues but is frequently expressed in certain types of cancer tissues. To clarify the oncogenic potential of cyclin D1b variant, we developed cyclin D1b transgenic (Tg) mice and analyzed their phenotypes. We detected rectal tumors in 63% (15/24) of the female Tg mice. All rectal tumors had the histological characteristics similar to human sessile serrated adenoma/polyps (SSA/Ps). Adenocarcinomas were also found in 53% (8/15) of the rectal tumors, suggesting that these adenocarcinomas originated from the SSA/P-like lesions. No rectal tumors were found in the ovariectomized female cyclin D1b Tg mice (0/10), indicating that ovarian hormones played a critical role in rectal carcinogenesis in these Tg mice. Both phosphorylation of Erk, without activating MEK, and expression of estrogen receptor β were elevated in the rectal tumors of female cyclin D1b Tg mice compared with normal rectums of female wild-type mice. In addition, we established a cell line, D1bTgRT, derived from a rectal cancer of female Tg mouse. Small interfering RNA-induced cyclin D1b knockdown in this cell line suppressed Erk phosphorylation, anchorage-independent growth, cell invasiveness and tumorigenicity in nude mice. In humans, expression of cyclin D1b messenger RNA was detected in 17% (1/6) of colorectal cancer cell lines and 9.7% (3/31) of colorectal cancer tissues. Taken together, these results indicate that cyclin D1b expression contributes to the female- specific rectal carcinogenesis in mouse model.

A common and functional gene variant in the vascular endothelial growth factor a predicts clinical outcome in early-stage breast cancer

Angiogenesis and cell cycle control play critical roles in breast cancer susceptibility and clinical outcome and are mainly controlled by vascular endothelial growth factor (VEGF) and cyclin-dependent kinases, respectively. Functional germline polymorphisms in these genes alter the function, thereby causing inter-individual differences in breast cancer risk and clinical outcome. In this study, we investigated the influence of the functional polymorphisms VEGF-A rs3025039 C > T and CCND1 rs9344 G > A on risk and clinical outcome in early-stage breast cancer. DNA of 539 female patients with histologically confirmed early-stage breast cancer and 804 control subjects was genotyped for these polymorphisms. Genotypes were tested for associations with breast cancer risk and clinical outcome. There was no significant association between the polymorphisms and breast cancer risk. However, the minor allele of VEGF-A rs3025039 C > T was significantly associated with decreased recurrence-free survival (HR 1.845; 95% confidence interval [CI] 1.035-3.290; P = 0.038) and remained significant in multivariate analysis (HR 1.880; 95% CI 1.020-3.465; P = 0.043). Patients carrying at least one A-allele in CCND1 rs9344 G > A showed a trend towards decreased recurrence-free survival in univariate analysis (HR 2.379; 95% CI 0.841-6.728; P = 0.068). This study provides evidence that the functional VEGF-A rs3025039 C > T polymorphism influences recurrence-free survival in early-stage breast cancer.

The cyclin D1 (CCND1) rs9344 G>A polymorphism predicts clinical outcome in colon cancer patients treated with adjuvant 5-FU-based chemotherapy

Recent evidence indicates a potential prognostic and predictive value for germline polymorphisms in genes involved in cell cycle control. We investigated the effect of cyclin D1 (CCND1) rs9344 G>A in stage II/III colon cancer patients and validated the findings in an independent study cohort. For evaluation and validation set, a total of 264 and 234 patients were included. Patients treated with 5-fluorouracil-based chemotherapy, carrying the CCND1 rs9344 A/A genotype had significantly decreased time-to-tumor recurrence (TTR) in univariate analysis and multivariate analysis (hazard ratio (HR) 2.47; 95% confidence interval (CI) 1.16-5.29; P=0.019). There was no significant association between CCND1 rs9344 G>A and TTR in patients with curative surgery alone. In the validation set, the A allele of CCND1 rs9344 G>A remained significantly associated with decreased TTR in univariate and multivariate analyses (HR 1.94; 95% CI 1.05-3.58; P=0.035). CCND1 rs9344 G>A may be a predictive and/or prognostic biomarker in stage II/III colon cancer patients, however, prospective trials are warranted to confirm our findings.

Expression of cyclin D1a and D1b as predictive factors for treatment response in colorectal cancer

Background:

The aim of this study was to investigate the value of the cyclin D1 isoforms D1a and D1b as prognostic factors and their relevance as predictors of response to adjuvant chemotherapy with 5-fluorouracil and levamisole (5-FU/LEV) in colorectal cancer (CRC).

Methods:

Protein expression of nuclear cyclin D1a and D1b was assessed by immunohistochemistry in 335 CRC patients treated with surgery alone or with adjuvant therapy using 5-FU/LEV. The prognostic and predictive value of these two molecular markers and clinicopathological factors were evaluated statistically in univariate and multivariate survival analyses.

Results:

Neither cyclin D1a nor D1b showed any prognostic value in CRC or colon cancer patients. However, high cyclin D1a predicted benefit from adjuvant therapy measured in 5-year relapse-free survival (RFS) and CRC-specific survival (CSS) compared to surgery alone in colon cancer (P=0.012 and P=0.038, respectively) and especially in colon cancer stage III patients (P=0.005 and P=0.019, respectively) in univariate analyses. An interaction between treatment group and cyclin D1a could be shown for RFS (P=0.004) and CSS (P=0.025) in multivariate analysis.

Conclusion:

Our study identifies high cyclin D1a protein expression as a positive predictive factor for the benefit of adjuvant 5-FU/LEV treatment in colon cancer, particularly in stage III colon cancer.

Proapoptotic, anti-cell proliferative, anti-inflammatory and anti-angiogenic potential of carnosic acid during 7,12 dimethylbenz[a]anthracene-induced hamster buccal pouch carcinogenesis

The present study has investigated the modulating effect of carnosic acid on the expression pattern of cell proliferative (proliferating cell nuclear antigen (PCNA) cyclin D1 and a transcription factor c-fos), apoptotic (p53, Bcl-2, Bax caspase -3 and 9), inflammatory (Nuclear factor kappa B (NFκB) and cyclooxygenase-2 (COX- 2) and angiogenic (vascular endothelial growth factor (VEGF) markers during 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch carcinogenesis. Oral tumors were developed in the hamsters buccal pouches by painting with 0.5% DMBA in liquid paraffin three times a week for 14 weeks. Hundred per cent tumour formation (well-differentiated squamous cell carcinoma) accompanied by deregulation in the above mentioned molecular markers was noticed in hamsters treated with DMBA alone (tumour bearing hamsters). Oral administration of carnosic acid at dose of 10mg/kg bw to hamsters treated with DMBA not only completely prevented the tumour formation, but also corrected the abnormalities in the expression pattern of molecular markers. The present study suggests that carnosic acid might have inhibited the tumour formation by exerting anti-cell-proliferative, anti-inflammatory, anti-angiogenic and apoptotic potential during DMBA-induced hamster buccal pouch carcinogenesis.

Cyclin D1 G870A polymorphism contributes to colorectal cancer susceptibility: evidence from a systematic review of 22 case-control studies

Background

Cyclin D1 (CCND1) plays a vital role in cancer cell cycle progression. Numerous epidemiological studies have evaluated the association between the CCND1 G870A polymorphism and the risk of colorectal cancer. However, these studies have yielded conflicting results. To derive a more precise estimation of this association, we conducted a meta-analysis and systematic review.

Methodology/Principal Findings

A comprehensive search was conducted to identify eligible studies of the CCND1 G870A polymorphism and colorectal cancer risk. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were derived from a fixed effect or random effect model. We applied a grading system (Venice criteria) that assessed the epidemiological strength of the association. A total of 22 publications that included 6157 cases and 8198 controls were identified. We found that the CCND1 G870A polymorphism was significantly associated with overall colorectal cancer risk (homozygote genetic model: OR = 1.130, 95% CI = 1.023–1.248, P = 0.016; heterozygote genetic model: OR = 1.124, 95% CI = 1.030–1.226, P = 0.009; dominant genetic model: OR = 1.127, 95% CI = 1.037–1.224, P = 0.005). After further stratified analyses, the increased risk was observed only in the subgroups of hospital-based studies, PCR-RFLP genotyping methods, sporadic colorectal cancer, and Caucasian ethnicity.

Conclusions

The available evidence demonstrates that the CCND1 870A allele might be a low-penetrant risk factor for colorectal cancer.

The Cyclin D1 (CCND1) A870G polymorphism predicts clinical outcome to lapatinib and capecitabine in HER2-positive metastatic breast cancer

BACKGROUND

Lapatinib plus capecitabine emerged as an efficacious therapy in metastatic breast cancer (mBC). We aimed to identify germline single-nucleotide polymorphisms (SNPs) in genes involved in capecitabine catabolism and human epidermal receptor signaling that were associated with clinical outcome to assist in selecting patients likely to benefit from this combination.

PATIENTS AND METHODS

DNA was extracted from 240 of 399 patients enrolled in EGF100151 clinical trial (NCT00078572; clinicaltrials.gov) and SNPs were successfully evaluated in 234 patients. The associations between SNPs and clinical outcome were analyzed using Fisher's exact test, Kaplan-Meier curves, log-rank tests, likelihood ratio test within logistic or Cox regression model, as appropriate.

RESULTS

There were significant interactions between CCND1 A870G and clinical outcome. Patients carrying the A-allele were more likely to benefit from lapatinib plus capecitabine versus capecitabine when compared with patients harboring G/G (P = 0.022, 0.024 and 0.04, respectively). In patients with the A-allele, the response rate (RR) was significantly higher with lapatinib plus capecitabine (35%) compared with capecitabine (11%; P = 0.001) but not between treatments in patients with G/G (RR = 24% and 32%, respectively; P = 0.85). Time to tumor progression (TTP) was longer in patients with the A-allele treated with lapatinib plus capecitabine compared with capecitabine (median TTP = 7.9 and 3.4 months; P < 0.001), but not in patients with G/G (median TTP = 6.1 and 6.6 months; P = 0.92).

CONCLUSION

Our findings suggest that CCND1A870G may be useful in predicting clinical outcome in HER2-positive mBC patients treated with lapatinib plus capecitabine.

CCND1 rs9344 polymorphisms are associated with the genetic susceptibility to cervical cancer in Chinese population

Cyclin D1, with a common G/A polymorphism in rs9344, is an essential regulator of the G1 phase in cell cycles and plays an important role in several tumor types, and the homology of cyclin D1 with human papillomavirus (HPV)-16 E7 brought our attention to CCND1 gene in cervical cancer. A total of 738 native Chinese subjects consist of 327 cases and 411 controls were enrolled in this study. CCND1 genotyping was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and partially verified by sequencing of genomic DNA and cDNA. The transcription of cyclin D1 mRNA isoforms was analyzed by quantitative PCR; expression of protein isoforms by immunohistochemistry and Western blotting. We observed that the AA genotype had decreased risk of developing cervical cancer (odds ratio [OR] = 0.332; 95% confidence interval [CI] = 0.113-0.978; P = 0.045). The two mRNA isoforms were both transcripted from A and G allele. Transcript b decreased in squamous cell carcinoma of the uterine cervix (SCCUC) group (P = 0.004), especially poorly differentiated group (P = 0.004), and in G allele group of normal subjects (P = 0.001). In immunohistochemistry analysis, cyclins D1, D1a, and D1b failed to correlate with cervical cancer (P = 0.808, 0.445, and 0.095). However, cyclin D1b was downregulated in SCCUC group analyzed by Western blotting (P = 0.039). This study indicates that CCND1 rs9344 polymorphisms confer host susceptibility to cervical cancer. A allele possesses a relative protective effect probably through the cyclin D1b's inhibition on HPV carcinogenesis.

Association of cyclin D1 gene polymorphisms with risk of esophageal squamous cell carcinoma in Kashmir Valley: a high risk area

Investigation of potential association of SNPs (G870A, rs9344; G1722C, rs678653) of cyclin D1 gene (CCND1) with susceptibility to esophageal squamous cell carcinoma (ESCC) in Kashmir valley (India). The study included 302 subjects comprising 151 ESCC cases and 151 controls. PCR-RFLP and direct sequencing were employed for genotyping. The G870A polymorphism, the individuals carrying GA + AA genotype was having 2.80-fold increased risk for development of ESCC (OR 2.8, 95% CI = 1.77-4.4; P = 0.0001) compared to GG genotype. Further a significantly higher risk was observed in individuals who consume >3 cups per day of salted tea (OR = 5.1; 95% CI = 1.6-16.7; P = 0.0016) and had smoking habits (OR = 6.3; 95% CI = 2.9-13.9; P = 0.0005). We also demonstrate for the first time in CCND1 1722 locus, the CC genotype was strongly associated with increased risk of developing ESCC (OR = 2.58; 95% CI = 1.61-4.15; P = 0.0001). In addition, the frequency of polymorphic C allele was also found to be higher in cases (OR = 1.92; 95% CI = 1.37-2.69; P = 0.0002). There appears to be an influence of CCND1 G870A/G1772C genotypes on genetic susceptibility to ESCC.

PACSIN 2 represses cellular migration through direct association with cyclin D1 but not its alternate splice form cyclin D1b

Cyclin D1 overexpression is a common feature of many human malignancies. Genomic deletion analysis has demonstrated a key role for cyclin D1 in cellular proliferation, angiogenesis, and cellular migration. To investigate the mechanisms contributing to cyclin D1 functions, we purified cyclin D1a-associated complexes by affinity chromatography and identified the PACSIN 2 (protein kinase C and casein kinase substrate in neurons 2) protein by mass spectrometry. The PACSIN 2, but not the related PACSIN 1 and 3, directly bound wild-type cyclin D1 (cyclin D1a) at the carboxyl terminus, and failed to bind cyclin D1b, the alternative splicing variant of cyclin D1. PACSIN 2 knockdown induced cellular migration and reduced cell spreading in LNCaP cells expressing cyclin D1a. In cyclin D1(-/-) mouse embryonic fibroblasts (MEFs), cyclin D1a, but not cyclin D1b, reduced the cell spreading to a polarized morphology. siPACSIN 2 had no effect on cellular migration of cyclin D1(-/-) MEFs. Cyclin D1a restored the migratory ability of cyclin D1(-/-) MEFs, which was further enhanced by knocking down PACSIN 2 with siRNA. The cyclin D1-associated protein, PACSIN 2, regulates cell spreading and migration, which are dependent on cyclin D1 expression.

Association between cyclin D1 polymorphism with CpG island promoter methylation status of tumor suppressor genes in gastric cancer

BACKGROUND

CpG island hypermethylation of tumor suppressor genes is highly involved in gastric carcinogenesis, and enhanced cell proliferation could accelerate this process. Cyclin D1 regulates cell cycle function and may play a role in methylation-related carcinogenesis.

AIMS

We investigated the association between Cyclin D1 gene G870A polymorphism and the methylation status of tumor suppressor genes in gastric cancer.

METHODS

Polymorphisms at G870A in the Cyclin D1 gene were genotyped, and methylation status of the p14, p16, DAP-kinase, and CDH1 genes were determined by methylation-specific-polymerase chain reaction in 139 gastric cancer tissues. CIHM high was defined as three or more methylated CpG islands.

RESULTS

Although no association was found between methylation status and different stages and Lauren's subtypes, patients with CIHM of DAP-kinase showed significantly worse survival than those without (p = 0.017). In addition, the number of methylated sites was also associated with survival curves (p = 0.0397). The 870G carrier a significantly lower prevalence of CIHM high compared to the AA genotype in advanced-stage gastric cancer (adjusted OR = 0.32, p = 0.047). A weak correlation between the same genotypes and CIHM of p14 were found in the same subtype (adjusted OR = 0.32, p = 0.052). The mean methylation number was significantly lower in G carriers than in AA genotypes in advanced-stage gastric cancer (p = 0.017).

CONCLUSIONS

Genetic polymorphism of CCND1 is associated with CIHM status in gastric cancer, especially in the advanced stage, but is independent of clinico-pathological features.

Candidate gene association study of esophageal squamous cell carcinoma in a high-risk region in Iran

There is a region with a high risk for esophageal squamous cell carcinoma (ESCC) in the northeast of Iran. Previous studies suggest that hereditary factors play a role in the high incidence of cancer in the region. We selected 22 functional variants (and 130 related tagSNPs) from 15 genes that have been associated previously with the risk of ESCC. We genotyped a primary set of samples from 451 Turkmens (197 cases and 254 controls). Seven of 152 variants were associated with ESCC at the P = 0.05 level; these single nucleotide polymorphisms were then studied in a validation set of 549 cases and 1,119 controls, which included both Turkmens and non-Turkmens. The association observed for a functional variant in ADH1B was confirmed in the validation set, and that of a tagSNP in MGMT, the association was borderline significant in the validation set, after correcting for multiple testing. The other 5 variants that were associated in the primary set were not significantly associated in the validation set. The histidine allele at codon 48 of ADH1B gene was associated with a significantly decreased risk of ESCC in the joint data set (primary and validation set) under a recessive model (odds ratio, 0.41; 95% confidence interval, 0.29-0.76; P = 4 x 10(-4)). The A allele of the rs7087131 variant of MGMT gene was associated with a decreased risk of ESCC under a dominant model (odds ratio, 0.79; 95% confidence interval, 0.64-0.96; P = 0.02). These results support the hypothesis that genetic predisposition plays a role in the high incidence of ESSC in Iran.

Candidate gene association study of esophageal squamous cell carcinoma in a high-risk region in Iran

There is a region with a high risk for esophageal squamous cell carcinoma (ESCC) in the northeast of Iran. Previous studies suggest that hereditary factors play a role in the high incidence of cancer in the region. We selected 22 functional variants (and 130 related tagSNPs) from 15 genes that have been associated previously with the risk of ESCC. We genotyped a primary set of samples from 451 Turkmens (197 cases and 254 controls). Seven of 152 variants were associated with ESCC at the P = 0.05 level; these single nucleotide polymorphisms were then studied in a validation set of 549 cases and 1,119 controls, which included both Turkmens and non-Turkmens. The association observed for a functional variant in ADH1B was confirmed in the validation set, and that of a tagSNP in MGMT, the association was borderline significant in the validation set, after correcting for multiple testing. The other 5 variants that were associated in the primary set were not significantly associated in the validation set. The histidine allele at codon 48 of ADH1B gene was associated with a significantly decreased risk of ESCC in the joint data set (primary and validation set) under a recessive model (odds ratio, 0.41; 95% confidence interval, 0.29-0.76; P = 4 x 10(-4)). The A allele of the rs7087131 variant of MGMT gene was associated with a decreased risk of ESCC under a dominant model (odds ratio, 0.79; 95% confidence interval, 0.64-0.96; P = 0.02). These results support the hypothesis that genetic predisposition plays a role in the high incidence of ESSC in Iran.

Cyclin D1 splice variants: polymorphism, risk, and isoform-specific regulation in prostate cancer

PURPOSE

Alternative CCND1 splicing results in cyclin D1b, which has specialized, protumorigenic functions in prostate not shared by the cyclin D1a (full length) isoform. Here, the frequency, tumor relevance, and mechanisms controlling cyclin D1b were challenged.

EXPERIMENTAL DESIGN

First, relative expression of both cyclin D1 isoforms was determined in prostate adenocarcinomas. Second, relevance of the androgen axis was determined. Third, minigenes were created to interrogate the role of the G/A870 polymorphism (within the splice site), and findings were validated in primary tissue. Fourth, the effect of G/A870 on cancer risk was assessed in two large case-control studies.

RESULTS

Cyclin D1b is induced in tumors, and a significant subset expressed this isoform in the absence of detectable cyclin D1a. Accordingly, the isoforms showed noncorrelated expression patterns, and hormone status did not alter splicing. Whereas G/A870 was not independently predictive of cancer risk, A870 predisposed for transcript-b production in cells and in normal prostate. The influence of A870 on overall transcript-b levels was relieved in tumors, indicating that aberrations in tumorigenesis likely alter the influence of the polymorphism.

CONCLUSIONS

These studies reveal that cyclin D1b is specifically elevated in prostate tumorigenesis. Cyclin D1b expression patterns are distinct from that observed with cyclin D1a. The A870 allele predisposes for transcript-b production in a context-specific manner. Although A870 does not independently predict cancer risk, tumor cells can bypass the influence of the polymorphism. These findings have major implications for the analyses of D-cyclin function in the prostate and provide the foundation for future studies directed at identifying potential modifiers of the G/A870 polymorphism.

Enhanced skin carcinogenesis and lack of thymus hyperplasia in transgenic mice expressing human cyclin D1b (CCND1b)

Cyclin D1b is an alternative transcript of the cyclin D1 gene (CCND1) expressed in human tumors. Its abundance is regulated by a single base pair polymorphism at the exon 4/intron 4 boundary (nucleotide 870). Epidemiological studies have shown a correlation between the presence of the G870A allele (that favors the splicing for cyclin D1b) with increased risk and less favorable outcome in several forms of cancer. More recently, it has been shown that, unlike cyclin D1a, the alternative transcript D1b by itself has the capacity to transform fibroblasts in vitro. In order to study the oncogenic potential of cyclin D1b, we developed transgenic mice expressing human cyclin D1b under the control of the bovine K5 promoter (K5D1b mice). Seven founders were obtained and none of them presented any significant phenotype or developed spontaneous tumors. Interestingly, K5D1b mice do not develop the fatal thymic hyperplasia, which is characteristic of the cyclin D1a transgenic mice (K5D1a). Susceptibility to skin carcinogenesis was tested in K5D1b mice using two-stage carcinogenesis protocols. In two independent experiments, K5D1b mice developed higher papilloma multiplicity as compared with wild-type littermates. However, when K5D1b mice were crossed with cyclin D1KO mice, the expression of cyclin D1b was unable to rescue the carcinogenesis-resistant phenotype of the cyclin D1 KO mice. To further explore the role of cyclin D1b in mouse models of carcinogenesis we carried out in silico analysis and in vitro experiments to evaluate the existence of a mouse homologous of the human cyclin D1b transcript. We were unable to find any evidence of an alternatively spliced transcript in mouse Ccnd1. These results show that human cyclin D1b has different biological functions than cyclin D1a and confirm its oncogenic properties.

Effect of cyclin D1 (CCND1) polymorphism on gastric premalignant condition

BACKGROUND

Cyclin D1 (CCND1) is known to regulate function in G1 arrest and therefore may play an important role in carcinogenesis. The aim of this study was to investigate the effect of G870A polymorphism of the CCND1 gene on gastric precancerous condition, on histological chronic gastritis, and on the risk of peptic ulcer diseases.

METHODS

Restriction fragment length polymorphism analysis was performed for polymorphisms at 870GA in the CCND1 gene in 524 cancer-free subjects, including 111 gastric and 54 duodenal ulcers, and 359 non-ulcer subjects. Gastritis scores of antral gastric mucosa were assessed according to the updated Sydney system in 384 subjects.

RESULTS

CCND1 genotype was significantly associated with the severity of intestinal metaplasia by the Kruskal-Wallis test, and this tendency was especially stronger among older subjects of 61 years or older (overall subjects: p=0.035, 61 years approximately : p=0.007). We also found that the 870AA genotype held a significant high risk of intestinal metaplasia [Helicobacter pylori infection adjusted odds ratio (OR)=1.8, 95% confidence interval (CI)=1.03-3.15, p=0.04]. The same genotype was more closely associated with the risk of intestinal metaplasia in older subjects of 61 years or older (H. pylori infection adjusted OR=3.45, 95% CI=1.48-8.08, p=0.004). A non-significant association was found between CCND1 G870A genotypes and the risk of peptic ulcer diseases as well as histological severity of acute or chronic inflammation.

CONCLUSIONS

It appears that the G870A polymorphism of CCND1 is associated with gastric premalignant condition especially in older subjects.

Cyclin D1b protein expression in breast cancer is independent of cyclin D1a and associated with poor disease outcome

Aberrant expression of cyclin D1 protein is a common feature of breast cancer. However, the CCND1 gene encodes two gene products, cyclin D1a and cyclin D1b, which have discrete mechanisms of regulation and impact on cell behavior. A polymorphism at nucleotide 870 in the CCND1 gene, rs603965, influences the relative production of the encoded proteins and can impart increased risk for tumor development. Here, the impact of both the G/A870 polymorphism and cyclin D1b protein production on breast cancer risk, disease phenotype and patient outcome was analysed. In a large multiethnic case-control study, the G/A870 polymorphism conferred no significant risk for breast cancer overall or by stage or estrogen receptor (ER) status. However, the cyclin D1b protein was found to be upregulated in breast cancer, independent of cyclin D1a levels, and exhibited heterogeneous levels in breast cancer specimens. High cyclin D1a expression inversely correlated with the Ki67 proliferation marker and was not associated with clinical outcome. In contrast, elevated cyclin D1b expression was independently associated with adverse outcomes, including recurrence, distant metastasis and decreased survival. Interestingly, cyclin D1b was particularly associated with poor outcome in the context of ER-negative breast cancer. Thus, specific cyclin D1 isoforms are associated with discrete forms of breast cancer and high cyclin D1b protein levels hold prognostic potential.

Genetic polymorphisms and head and neck cancer outcomes: a review

Head and neck cancer (HNC) patients have variable prognoses even within the same clinical stage and while receiving similar treatments. The number of studies of genetic polymorphisms as prognostic factors of HNC outcomes is growing. Candidate polymorphisms have been evaluated in DNA repair, cell cycle, xenobiotic metabolism, and growth factor pathways. Polymorphisms of XRCC1, FGFR, and CCND1 have been consistently associated with HNC survival in at least two studies, whereas most of the other polymorphisms have either conflicting data or were from single studies. Heterogeneity and lack of description of patient populations and lack of accounting for multiple comparisons were common problems in a significant proportion of studies. Despite a large number of exploratory studies, large replication studies in well-characterized HNC populations are warranted.

Oncogenic virus-associated neoplasia: a role for cyclin D1 genotypes influencing the age of onset of disease?

Cyclin D1 (CCND1) is a key regulatory protein at the G1/S checkpoint of the cell cycle. The purpose of our study was to assess the role of CCND1 genotypes influencing the age of onset of oncogenic virus-associated neoplasia. We conducted a hospital-based case-control study of 581 individuals, including 247 controls and 334 cases (108 nasopharyngeal and 226 cervical cancer cases). The polymorphism analysis was performed in blood samples by PCR-RFLP methodology. Age-adjusted logistic regression analysis indicates that individuals carrying two G-alleles have an increased genetic susceptibility for the development of oncogenic virus-associated cancers (aOR=2.02, 95% CI 1.30-3.14, P=0.002). Moreover, our results indicate that the waiting time for onset of oncogenic virus-associated neoplasia in patients homozygous (GG) for CCND1 genotypes (52 years) was 12 years earlier in comparison with patients carrying AG or AA genotypes (60 years) (log-rank test: P=0.0003). Our results may be important in contributing to a more extensive knowledge of the mechanisms involved in oncogenic virus-associated carcinogenesis, as CCND1 may be an important target for the development of new strategies for cancer treatment and prevention.

Alternate cyclin D1 mRNA splicing modulates p27KIP1 binding and cell migration

Cyclin D1 is an important cell cycle regulator, but in cancer its overexpression also increases cellular migration mediated by p27 KIP1 stabilization and RhoA inhibition. Recently, a common polymorphism at the exon 4-intron 4 boundary of the human cyclin D1 gene within a splice donor region was associated with an altered risk of developing cancer. Altered RNA splicing caused by this polymorphism gives rise to a variant cyclin D1 isoform termed cyclin D1b, which has the same N terminus as the canonical cyclin D1a isoform but a distinct C terminus. In this study we show that these different isoforms have unique properties with regard to the cellular migration function of cyclin D1. Although they displayed little difference in transcriptional co-repression assays on idealized reporter genes, microarray cDNA expression analysis revealed differential regulation of genes, including those that influence cellular migration. Additionally, whereas cyclin D1a stabilized p27 KIP1 and inhibited RhoA-induced ROCK kinase activity, promoting cellular migration, cyclin D1b failed to stabilize p27 KIP1 or inhibit ROCK kinase activity and had no effect on migration. Our findings argue that alternate splicing is an important determinant of the function of cyclin D1 in cellular migration.

Cyclin D1 Gene G870A Polymorphism Predicts Response to Neoadjuvant Radiotherapy and Prognosis in Rectal Cancer

PURPOSE

To investigate whether CCND1 genetic variations associated with a constitutive nuclear protein may influence either the pathologic response to preoperative RT or the prognosis in a series of rectal cancer patients.

METHODS AND MATERIALS

Seventy rectal cancer patients treated by neoadjuvant radiotherapy were included in the study. CCND1 exon 5 mutations were screened, and the G870A polymorphism was assessed for correlation with clinical variables, tumor response, and patient outcome.

RESULTS

No exon 5 mutation was found. Concerning the G870A polymorphism, the A/A variant was significantly associated with radiosensitivity (p = 0.022). Moreover, patients harboring the A allele were correlated with a lower risk of local failure (p = 0.017). Also, combination of the G870A polymorphism with the post-therapeutic lymph node status allowed the elaboration of a prognostic index, which accurately distinguished subgroups of patients with predictable recurrence-free (p = 0.003) and overall (p = 0.044) survival.

CONCLUSIONS

Although CCND1 exon 5 mutations are rare in rectal cancer, G870A polymorphism is a frequent variation that may predict radiosensitivity and prognosis.

Point mutations and genomic deletions in CCND1 create stable truncated cyclin D1 mRNAs that are associated with increased proliferation rate and shorter survival

A gene expression signature of tumor proliferation rate in mantle cell lymphoma (MCL) is an overriding molecular predictor of the length of survival following diagnosis. Many strongly proliferative MCL tumors have exceptionally high cyclin D1 mRNA levels and preferentially express short cyclin D1 mRNA isoforms. We demonstrate here that these short mRNAs are cyclin D1a isoforms with truncated 3'UTRs, not alternatively spliced cyclin D1b mRNA isoforms. Among 15 MCL tumors with truncated cyclin D1 mRNAs, 7 had genomic deletions in the CCND1 3'UTR region. In 3 others, CCND1 contained point mutations that created premature polyadenylation signals, giving rise to 1.5-kb mRNAs lacking most of the 3'UTR. Both types of genomic alteration created transcripts lacking mRNA destabilization elements present in the wild-type cyclin D1a mRNA. Premature polyadenylation due to a 3'UTR mutation also was present in the Z-138 MCL cell line, which expressed both truncated and full-length cyclin D1a mRNAs. In these cells, the half-life of the short cyclin D1a mRNA was much longer than that of the full-length mRNA. We conclude that alterations of CCND1 3'UTR structure can significantly increase its oncogenic effect and worsen the clinical course of MCL patients.

Diverse activation states of RhoA in human lung cancer cells: contribution of G protein coupled receptors

Rho GTPases play an essential role in the control of various cellular functions. Accumulating evidence suggests that RhoA overexpression contributes to human cancer development. However, the activation states of RhoA are poorly defined in cancer cells. In this study, we examined both the expression levels and the activation states of RhoA in various lung cancer cells by quantitative real-time reverse transcriptase-polymerase chain reaction and in vivo Rho guanine nucleotide exchange assay, respectively. Moreover, we dissected the signaling pathway from the cell surface receptors to RhoA using a broad-spectrum G protein coupled receptor (GPCR) antagonist, [D-Arg1,D-Trp5,7,9,Leu11]Substance P (SP), and a recently reported Galphaq/11-selective inhibitor, YM-254890. We found that RhoA was expressed highly in large cell carcinoma cells but only weakly in adenocarcinoma cells. The activation states of RhoA are considerably different from its expression profiles. We found that four of six small cell lung carcinoma (SCLC) cell lines exhibited a moderate to high activation rate of RhoA. The addition of [D-Arg1,D-Trp5,7,9,Leu11]SP reduced RhoA activity by almost 60% in H69 SCLC cells. The addition of YM-254890 had no effect on RhoA activity in H69 cells. Our results suggest that RhoA is activated in various lung cancer cells independent of its expression levels, and the high activation state of RhoA in SCLC cells mainly depends on a neuroendocrine peptide autocrine system which signals through Galpha12 coupled GPCR to RhoA. This study provides new insights into RhoA signaling in lung cancer cells and may help in developing novel therapeutic strategies against lung cancer.

Association of the A870G cyclin D1 gene polymorphism with genetic susceptibility to nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal cancer (NPC) is multifactorial, and the genetic background may be a crucial etiologic factor. Cyclin D1 (CCND1) is a key regulator of the cell cycle, and its altered activity is associated with the development of cancer.

METHODS

We analyzed the A870G CCND1 polymorphism by polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP) in 281 individuals, including 94 patients with NPC and 187 healthy individuals.

RESULTS

Our results indicate that individuals carrying two G alleles have a 2.17-fold increase in the risk for the development of NPC (odds ratio [OR], 2.17; 95% confidence interval [CI], 1.19-3.98; p = .016). Age-adjusted logistic regression analysis confirmed this association (adjusted odds ratio [aOR], 2.14; 95% CI, 1.14-4.04; p = .018). Multivariate analysis demonstrates an independent association between GG CCND1 genotype (aOR, 2.06), male sex (aOR, 2.66), and age at diagnosis (aOR, 2.02) regarding the development of undifferentiated NPC. The proportion of NPC cases attributable to the GG CCND1 genotype was 14.76%.

CONCLUSIONS

Our results may be important in the definition of a biologic predictive profile for the development of NPC within our population.

Cyclin D1 in non-small cell lung cancer: a key driver of malignant transformation

PURPOSE

To review the evidence implicating the deregulation of cyclin D1 in the pathogenesis of non-small cell lung cancer (NSCLC), and to discuss the opportunities for targeted clinical intervention.

METHODS

Data published until June 2006 are summarized, and previously unpublished results from our own research are included.

RESULTS

In normal cells, cyclin D1 complexes with and activates cyclin-dependent kinases (CDK) and acts as a transcriptional regulator. The protein is frequently overexpressed in a wide range of cancers, sometimes coincident with CCND1 (cyclin D1) gene amplification (5-20% of tumours). A low level of somatic mutations have been seen in certain tumours. CCND1 is amplified in NSCLC and cyclin D1 is frequently overexpressed in tumours and pre-invasive bronchial lesions, generally from one parental allele. Mutation analyses revealed a frequent CCND1 gene polymorphism (A870G) that modulates alternative splicing and allows expression of an alternative cyclin D1 transcript (transcript cyclin D1b). The encoded cyclin D1b protein lacks a specific phosphorylation site required for nuclear export. Genotype has been correlated with the risk and/or severity of disease or drug response across a range of malignancies, including lung cancer. Together, these findings suggest a strong pathological role for cyclin D1 deregulation in bronchial neoplasia.

CONCLUSION

Current data indicate that cyclin D1 overexpression is not a consequence of, but rather a pivotal element in the process of malignant transformation in the lung and other tissues. This understanding may open new avenues for lung cancer diagnosis, treatment and prevention.

Targeted disruption of protein kinase C epsilon reduces cell invasion and motility through inactivation of RhoA and RhoC GTPases in head and neck squamous cell carcinoma

Over 70% of patients with head and neck squamous cell carcinoma (HNSCC) present with locoregionally advanced stage III and IV disease. In spite of aggressive therapy, locoregional disease recurs in 60% and metastatic disease develops in 15% to 25% of patients causing a major decline in quality and length of life. Therefore, there is a need to identify and understand genes that are responsible for inducing an aggressive HNSCC phenotype. Evidence has shown that protein kinase C (PKC) epsilon is a transforming oncogene and may play a role in HNSCC progression. In this study, we determine the downstream signaling pathway mediated by PKC epsilon to promote an aggressive HNSCC phenotype. RNA interference knockdown of PKC epsilon in UMSCC11A and UMSCC36, two highly invasive and motile HNSCC cell lines with elevated endogenous PKC epsilon levels, resulted in cells that were significantly less invasive and motile than the small interfering RNA-scrambled control transfectants; 51 +/- 5% (P < 0.006) and 49 +/- 3% (P < 0.010) inhibition in invasion and 69 +/- 1% (P < 0.0005) and 66 +/- 3% (P < 0.0001) inhibition in motility, respectively. PKC epsilon-deficient UMSCC11A clones had reduced levels of active and serine-phosphorylated RhoA and RhoC. Moreover, constitutive active RhoA completely rescued the invasion and motility defect, whereas constitutive active RhoC completely rescued the invasion and partially rescued the motility defect of PKC epsilon-deficient UMSCC11A clones. These results indicate that RhoA and RhoC are downstream of PKC epsilon and critical for PKC epsilon-mediated cell invasion and motility. Our study shows, for the first time, that PKC epsilon is involved in a coordinated regulation of RhoA and RhoC activation, possibly through direct post-translational phosphorylation.

Association of the cyclin D1 gene G870A polymorphism with susceptibility to sporadic renal cell carcinoma

PURPOSE

Cyclin D1 (CCND1) mRNA is alternatively spliced to produce 2 transcripts (transcript-a and transcript-b), which may be modulated by a G870A single nucleotide polymorphism at the conserved splice donor site of exon 4. Previous studies have suggested a significant association between the CCND1 genotype and the development of various cancers. We explored the possible association between this polymorphism and the onset or disease statue of sporadic renal cell carcinoma (RCC).

MATERIALS AND METHODS

The CCND1 G870A genotype was determined in 191 RCC cases and in 400 controls by polymerase chain reaction restriction length polymorphism analysis.

RESULTS

Subjects with the AA genotype were at 1.70-fold significant higher risk for RCC than those with the GG genotype (age and sex adjusted OR 1.70, 95% 95% CI 1.03 to 2.82, p = 0.039). In addition, the A allele had a gene dose effect in increasing the risk of RCC (adjusted OR 1.30, 95% CI 1.01 to 1.67, p = 0.045). For tumor stage no significant difference in genotype frequency was found (p = 0.646).

CONCLUSIONS

These data suggest that the CCND1 variant A allele may be a genetic susceptibility factor with a recessive or gene dose effect for the onset of sporadic RCC. More extensive and larger studies are required to clarify whether the CCND1 genotype is more specifically involved in the onset of a histological subset of RCC or RCC at a younger age.

Impact of the cyclin D1 A870G polymorphism on susceptibility to sporadic colorectal cancer in Taiwan

PURPOSE

Cyclin D1 is a regulatory protein involved in the cell cycle of both normal and neoplastic cells. Polymorphism of this gene at codon 242 in exon 4 has impacts on risk of the early-age onset in several malignant neoplasms, including colorectal cancer. This investigation was designed to evaluate the effect of cyclin D1 gene polymorphism on the risk of colorectal cancer in Chinese migrants of the Taiwanese population.

METHODS

We enrolled 831 primary sporadic colorectal cancer patients as the study group and 1,052 age-gender matched healthy individuals as the control group (1,883 total cases) for present study. Cyclin D1 genotypes (AA, AG, GG) were determined using PCR-RFLP analysis on genomic DNA.

RESULTS

The frequency of G allele was 39.89 percent and 40.96 percent in the study group and the control group, respectively (P = 0.02). The patients were divided into three age groups for statistical analysis. The younger male patients had a higher frequency of AA/AG genotype compared with the controls (odds ratio, 2.75; 95 percent confidence interval, 1-7.9). The effect of AA/AG genotype on colorectal cancer risk was statistically significant for male patients (odds ratio, 1.34; 95 percent confidence interval, 1.04-1.72), but such phenomenon was not observed in female patients.

CONCLUSIONS

Our study suggests that the effect of cyclin D1 gene polymorphism on colorectal cancer risk is only observed in males and AA/AG genotype of cyclin D1 gene is associated with a higher risk of colorectal cancer in the younger patients within the Taiwanese population.

Cyclin D1: polymorphism, aberrant splicing and cancer risk

The cyclin D1 proto-oncogene exercises powerful control over the mechanisms that regulate the mitotic cell cycle, and excessive cyclin D1 expression and/or activity is common in human cancers. Although somatic mutations of the cyclin D1 locus are rarely observed, mounting evidence demonstrates that a specific polymorphism of cyclin D1 (G/A870) and a protein product of a potentially related alternate splicing event (cyclin D1b) may influence cancer risk and outcome. Herein, we review the epidemiological and functional literatures that link these alterations of cyclin D1 to human tumor development and progression.

Cyclin D1 (CCND1) A870G gene polymorphism modulates smoking-induced lung cancer risk and response to platinum-based chemotherapy in non-small cell lung cancer (NSCLC) patients

PURPOSE

The cyclin D1 (CCND1) A870G gene polymorphism is linked to the outcome in patients with resectable non-small cell lung cancer (NSCLC). Here, we investigated the impact of this polymorphism on smoking-induced cancer risk and clinical outcome in patients with NSCLC stages I-IV.

METHODS

CCND1 A870G genotype was determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis (RFLP) of DNA extracted from blood. The study included 244 NSCLC patients and 187 healthy control subjects.

RESULTS

Patient characteristics were: 70% male, 77% smokers, 43% adenocarcinoma, and 27% squamous cell carcinoma. Eighty-one percent of the patients had stages III-IV disease. Median age at diagnosis was 60 years and median survival was 13 months. Genotype frequencies of patients and controls both conformed to the Hardy Weinberg equilibrium. The GG genotype significantly correlated with a history of heavy smoking (>or=40 py, P=0.02), and patients with this genotype had a significantly higher cigarette consumption than patients with AA/AG genotypes (P=0.007). The GG genotype also significantly correlated with tumor response or stabilization after a platinum-based first-line chemotherapy (P=0.04). Survival analysis revealed no significant differences among the genotypes.

CONCLUSION

Evidence was obtained that the CCND1 A870G gene polymorphism modulates smoking-induced lung cancer risk. Further studies are required to explore the underlying molecular mechanisms and to test the value of this gene polymorphism as a predictor for platinum-sensitivity in NSCLC patients.

Influence of single nucleotide polymorphisms in H-Ras and cyclin D1 genes on oral cancer susceptibility

Although tobacco usage and alcohol consumption are the major risk factors for oral cancer, there are individual variations in genetic susceptibility to oral cancer. The Ras pathway plays an important role in oral carcinogenesis. High percentage of Ras mutation in oral carcinoma was reported from India. Cyclin D1, a downstream member of the Ras pathway, was also shown to be overexpressed in the majority of oral cancers and the overexpression was shown to be associated with poor prognosis. In the present study, we have evaluated the association of the single nucleotide polymorphisms in the H-Ras (C81T) and cyclin D1 (A870G and C1722G) genes and oral cancer risk in 176 oral cancer cases and 142 hospital based controls matched by age and sex. All the polymorphisms studied conformed to Hardy-Weinberg equilibrium. The comparison of the CCND1 A870G and C1722G genotype frequencies in cases and controls did not show any significant association with oral cancer risk. In H-Ras C81T polymorphism, TC+CC genotype showed a one and half fold increased risk (OR=1.59) for oral cancer. On stratified analysis, the observed increased risk was more evident among men (OR=2), while such an increased risk was not seen among women. Thus, our data suggests that the variant 'C' allele of the H-Ras (C81T) is associated with a higher risk for oral carcinoma, particularly in male population and thus, this polymorphism could be a low penetrance gene predisposition factor for oral carcinoma.

Elevated risk of colorectal cancer associated with the AA genotype of the cyclin D1 A870G polymorphism in an Indian population

PURPOSE

To investigate whether the common cyclin D1 (CCND1) A870G polymorphism is a risk factor for colorectal cancer (CRC) in an Indian population.

METHODS

In this study, 301 newly diagnosed CRC patients and 291 healthy control subjects were genotyped by the PCR-RFLP method. Genotype frequencies were compared between cases and controls, and the association of genotypes with CRC was studied.

RESULTS

The CCND1 870 A allele was more frequently observed in CRC patients than controls (0.63 vs. 0.56, P=0.01), and after adjustment for age, sex, smoking habits, family history, family income and the consumption of meat, fish, vegetables and fruit, an increased risk was observed for the AA genotype compared to the GG+AG genotype (OR=1.56; 95% CI: 1.10-2.21). The increased risk were also found for colon (OR=1.96; 95% CI: 1.08-3.57) and rectal cancer (OR=1.51; 95% CI: 1.04-2.19). No correlation was observed between genotypes and age of diagnosis of CRC (49.9, 48.7 and 49.4 years for the GG, AG and AA genotypes, respectively; P=0.84). Multivariate analysis also revealed a stronger positive association with the AA genotype among patients with high meat intake (OR=2.67; 95% CI: 1.29-5.51), and particularly significant inverse associations with the GG+AG genotypes were also found for those with high vegetable consumption (OR=0.46; 95% CI: 0.27-0.79 of 2-3 servings/day, and OR=0.31; 95% CI: 0.18-0.53 for >3 servings/day) and fish intake (OR=0.48; 95% CI: 0.28-0.82).

CONCLUSION

These data support the hypothesis that the CCND1 A870G polymorphism may increase the risk of CRC in our Indian population.

Cyclin D1 gene (CCND1) polymorphism and the risk of squamous cell carcinoma of the larynx

Cyclin D1 is one of the key proteins involved in cell cycle control, and it is believed that its overexpression may be connected with tumorigenesis. A reason for cyclin D1 deregulation may be connected to a common G870A polymorphism at codon 242 in exon 4 of the CCND1 gene. This single nucleotide substitution, localized in the conserved splice donor site between exon 4 and the intron 4 boundary, might modulate the frequency of alternative splicing. It has been postulated that the A allele results in a higher level of mRNA (transcript b) encoding a protein with an altered C-terminal domain. The influence of CCND1 G-->A polymorphism for the risk of cancer and the prognosis of patients with different types of solid tumors has already been suggested. This study was conducted to investigate the association between the cyclin D1 gene polymorphism and laryngeal cancer risk, as well as the clinical outcome. We also examined the relationship between genotype/allele distributions and the cyclin D1 expression profile. The genotyping study was done using the PCR-RFLP method in 63 patients with larynx cancer and 102 healthy controls. The heterozygotic genotype GA as well as a combination of GA and AA genotypes were associated with an increased risk of larynx cancer compared to the GG genotype (OR =3.02; P =0.004 and OR =2.52; P =0.013, respectively). The A allele frequency was higher in cancer cases (0.484) than in controls (0.416) that were connected with a slightly increased risk of cancer development (OR =1.34); however, the difference was not significant. The AA genotype was associated with an early cancer onset compared to the GG genotype (median age: 51.5 and 63.0 years, respectively). We also demonstrated that the AA genotype was associated with the occurrence of lymph node metastases (OR =3.26) and a higher level of cyclin D1 overexpression. These results suggest that the CCND1 A allele may be a genetic factor that modulates the risk of larynx cancer development, and it may also have an effect on tumor biology and disease prognosis.

Cyclin D1 Genotype and Expression in Sporadic Hemangioblastomas

Central nervous system (CNS) hemangioblastomas are highly-vascularized tumors occurring in sporadic form or as a manifestation of von Hippel-Lindau disease (VHL). The VHL protein (pVHL) regulates various target genes, one of which is the CCND1 gene, encoding cyclin D1, a protein that plays a critical role in the control of the cell cycle. Overexpression of cyclin D1 is found in many cancers. The CCND1 gene contains a common G --> A polymorphism (870G > A) that enhances alternative splicing of the gene. CCND1 genotype is associated with clinical outcome in a number of cancers although prognostic significance varies with tumor type. In VHL disease, CCND1 genotype has been suggested as a genetic modifier that influences susceptibility to hemangioblastomas. In order to analyze whether CCND1 genotype plays a role in sporadic CNS hemangioblastomas, we investigated CCND1 genotype in tumor tissue of 17 sporadic and also in five VHL-related CNS hemangioblastomas. In addition, in these tumors the extent and localization of cyclin D1 expression was investigated by immunohistochemistry. We found no deviation in CCND1 genotype distribution and allele frequencies from expected values. Also, there was no correlation between age at onset and CCND1 genotype. The expression of cyclin D1 as detected by immunohistochemistry was highly variable within and between tumors, without a clear correlation with CCND1 genotype. We conclude that, whereas variable but sometimes high cyclin D1 expression is a feature of sporadic hemangioblastomas, CCND1 genotype is unlikely to be an important genetic modifier in the oncogenesis of these tumors.

Functional promoter SNPs in cell cycle checkpoint genes

A substantial number of genes mutated in human cancers encode components of the cell cycle processes. As the G1/S transition in the cell cycle is a finely regulated biological process, we hypothesized that sequence variations in the promoter region of the related genes might indeed lead to abnormal expression, thus predisposing the individuals carrying these genetic variants to cancer. In this report, we screened the promoter regions of 16 cell cycle checkpoint genes for DNA variants and assessed the functional impact of these promoter region single nucleotide polymorphisms (pSNPs) by combining in silico analysis and in vitro functional assays. We identified 127 pSNPs including 90 with predicted impact on putative binding sites of known transcription factors. Eleven pSNPs were selected for electrophoresis mobility shift assays because of their association with predicted gains of binding sites, and nine pSNPs showed differential allelic shifts in at least one cell line tested. Following the subcloning of the promoter regions into a gene reporter system, we found that at least four promoter haplotypes associated with CCND1, E2F1, HDAC1 and RB1 significantly influenced transcriptional activity in an allele-specific manner. Although the biological significance of these observations still remains to be demonstrated, the expected variability of expression levels in key cell cycle components might influence individual's risk of cancer.

Increased risk of cervical cancer associated with cyclin D1 gene A870G polymorphism

Human papillomavirus (HPV) plays a major role in the etiology of cervical cancer. However, a complex correlation between viral and cellular genes is necessary for cell cycle control deregulation in the progression to invasive cervical cancer (ICC). Cyclin D1 (CCND1) is an important positive regulator of the G1/S phase of the cell cycle. The CCND1 gene is located at 11q13 and is often altered in human cancers. We analyzed the A870G CCND1 polymorphism by polymerase chain reaction/restriction fragment length polymorphism analysis in 246 women including 50 cases with high-grade squamous intraepithelial lesions of the cervix (HSIL), 93 with ICC, and 103 healthy women. The GG genotype was associated with a 4.32-fold higher risk for the development of HSIL [adjusted odds ratio (aOR)=4.32, 95% confidence interval (CI) 1.50-12.46, P=0.0067), and a 3.26-fold increased risk for the development of ICC (aOR=3.26, 95% CI 1.42-7.53, P=0.006). The proportion of cervical cancer cases attributable to the GG CCND1 genotype was 17.26%. This study indicates that the A870G CCND1 polymorphism could act as a cofactor of HPV in the initiation of cervical carcinogenesis, particularly in the transformation zone of HPV-infected women, supporting evidence for a genetic factor in ICC risk.