Clinical significance of CDC25A and CDC25B expression in squamous cell carcinomas of the oesophagus

CDC25A, CDC25B and CDC25C belong to a family of protein phosphatases which activate the cyclin-dependent kinase at different points of the cell cycle. According to accumulating evidence, CDC25A and CDC25B seem to possess oncogenic properties. We have analysed these expressions by immunohistochemistry, western blot and RT-PCR in a series of 100 patients with squamous cell carcinoma of the oesophagus. When compared with non-cancerous cells, CDC25A and CDC25B were strongly expressed in the cytoplasm of cancer cells, with positive (+) classification in 46% (46 cases) and 48% (48 cases), respectively. There was no significant correlation between CDC25A and CDC25B expression, nor was there any association with the expression of other cell cycle-regulating molecules, including cyclin D1, Rb, p16(INK4), p27(KIP1)and PCNA (proliferating cell nuclear antigen). CDC25A (+), as well as CDC25B (+), was more frequently found in patients with deeper tumour invasion and lymph node metastasis, while tumour size was correlated only with CDC25A expression. Postoperative survival was significantly poorer for CDC25A (+) patients than CDC25A (-) patients, but was not affected by the CDC25B status. Nuclear localization of CDC25A was observed in 51 cases (51%), regardless of its cytoplasmic expression, and was not associated with clinico-pathological factors or prognosis. Multivariate analysis revealed only the CDC25A status to be an independent significant prognostic factor among these biological and clinico-pathological factors. CDC25A but not CDC25B may be a new prognostic factor for squamous cell carcinoma of the oesophagus. Thus, regulation of the G1 checkpoint in the cell cycle may be important in oesophageal carcinogenesis, which may also involve many other oncogenes.     

CDC25B与恶性肿瘤研究进展

CDC25（A、B和C）是双特异性蛋白磷酸酶,在细胞周期中充当重要的角色。CDC25B是CDC25激酶家族的最重要成员,贯穿细胞周期的各阶段,在不同时期存在于细胞内不同的位置,其在细胞周期各期转换中起关键作用,在细胞有丝分裂过程中发挥重要作用。肩负激活CDK1（cyclin dependent kinases-1）-cyclinB的重大责任,是早期有丝分裂的启动因子,同时也是卵母细胞恢复减数分裂的核心调控因子。CDC25B是磷酸化蛋白,其活性的调节是通过磷酸化和去磷酸化进行的,其编码基因定位于20p13,编码酪氨酸磷酸酶,已被认为是一种新的癌基因。过量CDC25B可促进肿瘤生长和细胞恶性转化。其基因过度表达可能发生在恶性肿瘤的早期阶段,进而引起CDC25B基因表达异常紊乱,发生肿瘤改变。CDC25B在多种肿瘤中如结肠癌、胰腺癌、卵巢癌、乳腺癌、肺癌和非霍奇金氏淋巴瘤等均有过度表达,并且与患者预后相关,为恶性肿瘤预后不良的危险因素。CDC25B基因已成为恶性肿瘤治疗的新靶点,近年来已有研究并合成了CDC25B抑制剂,有望成为防治恶性肿瘤的可行途径之一。     

CDC25B在肾癌细胞中的作用

目的:探讨CDC25B在肾癌组织和细胞中的表达状况及对肾癌细胞凋亡、运动以及侵袭力的影响。方法:免疫组化检测肾癌组织中CDC25B的表达,Western blot和RT-PCR检测CDC25B蛋白在肾癌769-P和ACHN细胞中的表达。挑选表达量大的细胞系转染CDC25B shRNA。MTT法检测细胞增殖能力。Annexin V-FITC/PI-FCM实验检测肾癌细胞凋亡。Transwell 检测肾癌细胞侵袭力。结果:CDC25B在肾癌组织中高表达。CDC25B在肾癌769-P和ACHN细胞中均表达,ACHN的恶性度高于769-P,CDC25B在ACHN中表达高于769-P。CDC25B蛋白被干扰后,随着时间的延长,肾癌ACHN细胞的增殖能力显著降低,各时间组与浓度组之间差异具有统计学意义。CDC25B蛋白被干扰后,肾癌ACHN细胞的凋亡增加。体外运动减弱。小室侵袭实验表明,干扰组的细胞数低于对照组,差异具有统计学意义（P<0.05）。干扰后降低了肿瘤细胞的侵袭能力。结论:CDC25B在肾癌中的表现为原癌基因的作用,CDC25B与肾癌的恶性程度呈正相关。CDC25B可能成为肾癌潜在的诊断标记和新的判定肿瘤恶性度的指标。     

CDC25B1对人胰腺癌细胞株Patu8988的生物学行为的影响

目的 探讨CDC25B1基因在人胰腺癌细胞株Patu8988中的表达情况,并将真核表达重组载体pcDNA-CDC25B1转染至细胞中,观察CDC25B1基因对细胞生物学行为的影响,以了解它在细胞周期及胰腺肿瘤细胞恶性转化方面的作用,为研究胰腺癌的发病机制与治疗提供理论依据.方法 利用Lipolectamine2000将CDC25B1转染至人胰腺癌细胞株Patu8988中,通过RT-PCR和Western blot在mRNA和蛋白水平验证质粒转染成功,通过MTT实验、侵袭实验和细胞周期检测,观察CDC25B1对细胞生物学行为的影响. 结果 RT-PCR发现在胰腺癌细胞株Patu8988和转染空质粒的细胞株中,CDC25B1在mRNA水平表达很弱;转染pcDNA-CDC25B1组中CDC25B1高表达.Western blot发现在胰腺癌细胞株Patu8988中,CDC25B蛋白有少量表达;转染pcDNA-CDC25B1组CDC25B蛋白高表达.MTT实验显示,转染pcDNA-CDC25B1组的细胞生长在72 h受到明显抑制(P<0.05).侵袭实验显示,转染pcDNA-CDC25B1的细胞其穿透Matrigel胶的能力明显增强(P<0.05).流式细胞计量术显示,转染了pcDNA-CDC25B1组中,G1期的细胞明显增多(P<0.05);同时转染了pcDNA-CDC25B1组中,G2期的细胞明显减少,与未处理组比较有统计学意义(P<0.05). 结论 在胰腺癌细胞株Patu8988中的CDC25B1转录水平很弱,存在少量CDC25B蛋白表达.转染的CDC25B1基因提高CDC25B1蛋白的表达,使细胞停滞在G1期,对细胞的生长有抑制作用,但能够增强细胞的侵袭能力;CDC25B1可能不是通过单一的调控细胞周期而实现其对细胞的影响,还存在其它多种途径.     

Overexpression of Cyclin-dependent Kinase-activating CDC25B Phosphatase in Human Gastric Carcinomas

CDC25 phosphatases activate cyclin-dependent kinases by removing inhibitory phosphate groups on the molecules and positively regulate the cell cycle progression. The expression of CDC25A, B and C was examined in gastric carcinoma cell lines and gastric carcinoma tissues by northern blotting and immunohistochemistry. The gastric carcinoma cell lines expressed CDC25A, B and C mRNA at various levels. The expression levels of CDC25B were generally higher than those of CDC25A and C. Of the 40 gastric carcinomas, 70% of the tumors expressed CDC25B mRNA at higher levels than the corresponding normal mucosas, while 38% overexpressed CDC25A mRNA. The CDC25C expression was at very low or undetectable levels. No obvious correlation was detected between the expression of CDC25B and p53 gene mutations. Inununohistochemically, CDC25-positive tumor cells were detected in 43 (78%) of 55 gastric carcinoma cases, of which 27 (49%) were strongly positive. Strong expression of CDC25B protein was associated with advanced stage and deep invasion. Furthermore, the incidence of strong expression was significantly higher in carcinomas with nodal metastasis than in those without metastasis. These findings suggest that Overexpression of CDC25B may favor development and progression and may be an indicator of malignant behavior of gastric carcinomas.     

Occupational exposure to arsenic and risk of nonmelanoma skin cancer in a multinational European study

Occupational studies show a high risk of lung cancer related to arsenic exposure by inhalation; however, only a few studies, and with conflicting results, previously examined a potential link between arsenic exposure at work and skin cancer. The aim of this study is to assess airborne arsenic exposures at the workplace and to quantify associations with nonmelanoma skin cancer (NMSC). The study sample consists of 618 incident cases of NMSC and 527 hospital‐based controls aged 30–79 years from Hungary, Romania and Slovakia. Exposures were evaluated by local experts using occupational histories. Information on host factors and other exposures was collected and used to adjust the associations of interest using multivariable logistic regression. The lifetime prevalence of exposure to work‐related arsenic is 23.9% for cases and 15.5% for controls. No significant association between arsenic exposure in the workplace and NMSC was detected, although an increased adjusted odd ratio was observed for participants with higher cumulative lifetime workplace exposure to arsenic in dust and fumes compared to referents [odds ratios (OR) = 1.94, 95% confidence interval (CI) = 0.76–4.95]. There is evidence for modification of the workplace arsenic–NMSC association by work‐related sunlight exposure in women, with a markedly increased adjusted OR in the presence of workplace sunlight exposure (OR = 10.22, 95% CI = 2.48–42.07). Workplace coexposure to arsenic and sunlight may thus pose an increased risk of NMSC.     

Site-specific occurrence of nonmelanoma skin cancers in patients with cutaneous melanoma

In a registry-based case-control study, we compared the site-specific occurrence of nonmelanoma (keratinocytic) skin cancers among patients with cutaneous melanoma cases (cases, n = 3774) and solid tumours (controls, n = 349,923), respectively. Overall, patients with melanoma were almost five-fold more likely to develop keratinocytic cancers compared with solid tumour controls (adjusted OR 4.7, 95% CI 4.1-5.3), but the risks varied depending upon the site of melanoma. Whereas patients with melanoma of the head and neck had similarly increased risks of keratinocytic cancers across all body sites, patients with melanoma of the trunk were significantly more likely to develop keratinocyte cancer diagnosed on the trunk (adjusted OR 12.5, 95% CI 7.2-20.2) than on the head and neck (adjusted OR 3.0, 95% CI 2.2-4.3). Similar colocalisation of skin tumours was observed for patients with melanomas of the lower limb. These findings provide support for the hypothesis that skin cancers at different anatomical sites may arise through different causal pathways.     

Genotoxic stress modulates CDC25C phosphatase alternative splicing in human breast cancer cell lines

CDC25 (cell division cycle 25) phosphatases are essential for cell cycle control under normal conditions and in response to DNA damage. They are represented by three isoforms, CDC25A, B and C, each of them being submitted to an alternative splicing mechanism. Alternative splicing of many genes is affected in response to genotoxic stress, but the impact of such a stress on CDC25 splicing has never been investigated. In this study, we demonstrate that genotoxic agents (doxorubicin, camptothecin, etoposide and cisplatin), alter the balance between CDC25C splice variants in human breast cancer cell lines both at the mRNA and protein levels. This modulation occurs during the response to moderate, sub-lethal DNA damage. Our results also suggest that the CDC25C splice variants expression shift induced by a genotoxic stress is dependent on the ATM/ATR signaling but not on p53. This study highlights the modulation of CDC25C alternative splicing as an additional regulatory event involved in cellular response to DNA damage in breast cancer cells.     

CDC 25A和CDC 25B基因在宫颈癌中的表达和临床意义

目的：检测及讨论CDC 25A和CDC 25B基因在宫颈癌中的表达水平及其临床意义。分析CDC 25A和CDC 25B基因剪切变异分子CDC 25A1—2、CDC 2581—4在宫颈组织中的表达分布规律。方法：采用RT—PCR和Western印迹法检测61例宫颈癌组织、18例宫颈良性病变组织中CDC 25的表达情况，并分析CDC 25的表达水平与宫颈癌临床病理参数之间的关系。结果：CDC 25A和CDC 25B基因在宫颈癌组织和宫颈良性病变组织中的表达差异有统计学意义（P〈0．05）；CDC 25的各剪切变异分子表达在宫颈癌患者不同年龄、癌组织病理类型、临床分期及癌细胞分化程度间差异有统计学意义（P〈0．05），而与宫颈癌的淋巴结转移无关（P〉0．05）。结论：宫颈癌组织中存在CDC 25A和B的高表达，CDC 25分子及其剪切变异体的表达异常可能是宫颈癌发生、发展的重要细胞内调控机制之一。     

Nonsteroidal anti‐inflammatory drugs and the risk of nonmelanoma skin cancer

Nonsteroidal anti‐inflammatory drugs (NSAIDs) have been assigned a promising role in the chemoprevention of various malignancies. However, epidemiological data on the association between NSAID use and nonmelanoma skin cancer (NMSC) are limited. To explore whether patients regularly exposed to systemic NSAIDs are at a reduced risk of basal cell carcinoma (BCC) or squamous cell carcinoma (SCC), we conducted a population‐based case‐control analysis using the Clinical Practice Research Datalink, a United Kingdom primary care database. We identified 65,398 patients with incident BCC and 7,864 patients with incident SCC diagnosed between 1995 and 2013 and matched 1 and 4 NMSC‐free controls to each BCC and SCC case, respectively, on age, sex, general practice, calendar time and years of history in the database. We compared prior NSAID exposure between cases and controls using multivariate conditional logistic regression analyses controlling for several potential confounders. Overall, we found no association between NSAID use and BCC, but when looking exclusively at users of single NSAID substances there was a suggestion of a reduced BCC risk in regular users of aspirin and ibuprofen (adjusted odds ratio [adj. OR]: 0.92, 95% confidence interval [CI]: 0.85–0.99 and adj. OR: 0.61, 95% CI: 0.48–0.78, respectively). The risk of SCC was slightly decreased in regular users of any NSAIDs (adj. OR: 0.89, 95% CI: 0.82–0.97), with the strongest risk reduction observed in current users of coxibs (adj. OR: 0.77, 95% CI: 0.62–0.95). These findings provide evidence that patients predisposed to NMSC might benefit from chemoprevention with NSAIDs.     

CDC25B在乳腺癌中的表达及其临床意义

[目的]评价细胞分裂周期蛋白25B（CDC25B）在乳腺癌中的表达及意义。[方法]2004年1月至2005年12月经病理证实的女性原发性浸润性乳腺癌111例,采用免疫组化方法检测CDC25B表达情况。[结果]CDC25B高表达47例,占42.3%（47/111）。CDC25B高表达组中腋淋巴结阳性26例,占55.3%（26/47）;低表达组中腋淋巴结阳性23例,占35.9%（23/64）,两组间淋巴结转移率差异有统计学意义（P=0.042）。CDC25B高表达组与低表达组的5年生存率分别为80.9%和92.2%（Log-Rankχ2=4.384,P=0.036）。[结论]乳腺癌组织中CDC25B高表达可能与乳腺癌的发生、发展及转移有关。     

Trends in the incidence of nonmelanoma skin cancer in Denmark 1978–2007: Rapid incidence increase among young Danish women

Nonmelanoma skin cancer (NMSC) is the most common cancer among Caucasian populations worldwide, and incidence rates are increasing. However, NMSC data are not routinely collected by cancer registries, but Denmark has extensive registration of NMSC in two nationwide population‐based registries. We assessed incidence trends of NMSC in Denmark from 1978 to 2007. Data for basal cell carcinoma ( BCC) and squamous cell carcinoma (SCC) were obtained from the Danish Cancer Registry and the Danish Registry of Pathology. For both genders, age‐specific incidence rates and overall incidence rates, age‐adjusted according to the World standard population were calculated based on combined data from the two registries. For both genders, a high increase in both BCC and SCC incidence was observed over time. Between 1978 and 2007, the age‐adjusted BCC incidence increased from 27.1 to 96.6 cases per 100,000 person‐years for women and from 34.2 to 91.2 cases for men. The SCC incidence increased from 4.6 to 12.0 cases per 100,000 person‐years for women and from 9.7 to 19.1 cases for men. For both BCC and SCC, women experienced a higher average annual percentage incidence change than men. Furthermore, the average annual percentage change in BCC incidence among persons below 40 years was significantly higher compared to older persons, especially for women. These trends may lead to an alarming NMSC incidence increase over time as population ages and will have major implications for future healthcare services. Our findings underline the need for improved preventive strategies to hamper the increasing NMSC incidence.     

IRC‐083864, a novel bis quinone inhibitor of CDC25 phosphatases active against human cancer cells

CDC25 phosphatases are key actors in cyclin‐dependent kinases activation whose role is essential at various stages of the cell cycle. CDC25 expression is upregulated in a number of human cancers. CDC25 phosphatases are therefore thought to represent promising novel targets in cancer therapy. Here, we report the identification and the characterization of IRC‐083864, an original bis‐quinone moiety that is a potent and selective inhibitor of CDC25 phosphatases in the low nanomolar range. IRC‐083864 inhibits cell proliferation of a number of cell lines, regardless of their resistance to other drugs. It irreversibly inhibits cell proliferation and cell cycle progression and prevents entry into mitosis. In addition, it inhibits the growth of HCT‐116 tumor spheroids with induction of p21 and apoptosis. Finally, IRC‐083864 reduced tumor growth in mice with established human prostatic and pancreatic tumor xenografts. This study describes a novel compound, which merits further study as a potential anticancer agent. © 2008 Wiley‐Liss, Inc.     

Measures of cutaneous human papillomavirus infection in normal tissues as biomarkers of HPV in corresponding nonmelanoma skin cancers

Cutaneous human papillomavirus (HPV) may be associated with the development of nonmelanoma skin cancer (NMSC), as suggested by reports of HPV DNA in NMSC tumors. HPV has also been investigated as an NMSC risk factor in epidemiologic studies, although findings vary across studies that used different biomarkers of HPV infection in normal tissues. To identify appropriate biomarkers for use in future epidemiologic studies, we conducted a sampling validation study. NMSC tumor tissue was obtained from 20 patients with pathology-confirmed basal or squamous cell carcinoma of the skin, in addition to several normal tissues, including eyebrow hairs, normal skin swabs obtained using multiple techniques, normal skin punch and shave biopsies, and serum for antibody measurement. Presence of cutaneous HPV DNA in tissues was measured with multiplex PCR using HPV type-specific primers and array primer extension (APEX) for HPV typing. Antibody detection was based on glutathione-S-transferase capture ELISA in combination with fluorescent bead technology. Using HPV DNA in tumor tissues as a gold standard, sensitivity and specificity were calculated for each measure of HPV infection in normal tissues. beta-Papillomavirus DNA was observed in tumor tissues in 60% of patients. The normal skin punch biopsy demonstrated optimal sensitivity (75%) and specificity (75%). Biomarkers obtained using less-invasive techniques demonstrated poor specificity when considered individually, although specificity improved when biomarkers were combined. Based on the current case series, the combinations of antibodies+eyebrow hairs or antibodies+eyebrow hairs+Dacron swabs are the optimal, minimally invasive markers of cutaneous HPV infection for use in epidemiologic studies.     

Prospective study of genital human papillomaviruses and nonmelanoma skin cancer

Genital high‐risk human papillomaviruses (HPVs) cause cervical cancer and are also found in a small proportion of nonmelanoma skin cancers (NMSCs). We used cancer registry linkages to follow the 856,000 serum donors included in the Southern Sweden Microbiology Biobank or the Janus Biobank in Norway, for incident skin cancers occurring up to 30 years after serum donation. Serum samples taken before diagnosis of squamous cell carcinoma (SCC) (N = 633), basal cell carcinoma (BCC) (N = 1990) or other NMSC (N = 153) and matched samples from control donors were tested for antibodies to the genital HPV types 16 and 18. Both HPV 16 and 18 were associated with increased risk for SCC [odds ratio (OR) 1.6, 95% confidence interval (CI) 1.1–2.6 and OR 1.7, 95% CI 1.1–2.5, respectively] and other NMSC (OR 2.3, 95% CI 1.0–5.2 and OR 3.5, 95% CI 1.4–8.7, respectively), but not for BCC. Tumor blocks from HPV16 or 18 seropositive cases were tested with real‐time polymerase chain reaction for presence of HPV16 or 18 DNA. No HPV18 DNA was found and only four of 79 SCC cases (two of which were from the perineum/perianal area), one of 221 BCC cases and zero of five cases with other NMSC contained HPV16 DNA. In conclusion, we found prospective evidence that HPV16 and 18 antibodies associate with SCC and other NMSC risk, but not with BCC risk. As only a small proportion of seropositive subjects had evidence of the corresponding HPV DNA in the tumor, most of this excess risk is likely to be due to confounders associated with genital HPV infection.     

Niacin intake and risk of skin cancer in US women and men

A recent clinical trial found a protective role of niacinamide, a derivative of niacin, against skin cancer recurrence. However, there is no epidemiologic study to assess the association between niacin intake and risk of skin cancer [basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and melanoma]. We prospectively evaluated whether total, dietary and supplemental niacin intake was associated with skin cancer risk based on 72,308 women in the Nurses' Health Study (1984–2010) and 41,808 men in the Health Professionals Follow‐up Study (1986–2010). Niacin intake was assessed every 2 to 4 years during follow‐up and cumulative averaged intake. Cox proportional hazard models were used to compute the hazard ratios (HR) and 95% confidence intervals (CI) and cohort‐specific results were pooled using a random‐effects model. During the follow‐up, we documented 23,256 BCC, 2,530 SCC and 887 melanoma cases. Total niacin intake was inversely associated with SCC risk; the pooled HR for top vs. bottom quintiles was 0.84 (95% CI = 0.74–0.95; p_trend = 0.08). However, there were a marginally positive association between total niacin intake and BCC risk; the pooled HR for top versus bottom quintiles was 1.05 (95% CI = 1.01–1.10; p_trend < 0.01). Higher total niacin intake was also marginally positively associated with melanoma risk in men, but not in women. The results were similar in stratified analyses according to sun exposure related factors and by body location of melanoma and SCC. Our study supports a potential beneficial role of niacin intake in relation to SCC but not of BCC or melanoma.     

Vitamin and carotenoid intake and risk of squamous cell carcinoma of the skin

Our objective was to examine prospectively the intake of vitamins A (including retinol and total vitamin A), C and E; folate; total carotene; and several individual carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin and lutein/zeaxanthin) in relation to incidence of SCC of the skin in 2 large cohorts of men and women. We used a prospective cohort study design with up to 14 years of follow-up in women and 10 years in men. Diet was measured with FFQs every 2-4 years; cases of SCC of the skin were ascertained on biennial questionnaires and confirmed by medical records. Participants were female nurses and male health professionals, from the Nurses' Healthy Study and the Health Professionals Follow-up Study in the United States, without a history of any cancer in 1982 (n = 85,944 women) and 1986 (n = 43,867 men). Follow-up response was achieved for over 90% of potential person-years. Relative risks and 95% confidence intervals for development of SCC of the skin are reported. We recorded 369 cases of SCC in women and 305 cases in men. After multivariate adjustment for various known behavioral, sun-exposure and sun-sensitivity risk factors for SCC, there were no significant inverse associations between these dietary factors and SCC incidence. No evidence was found that vitamins A, C and E; folate; or carotenoids play an important protective role against incident SCC.     

沉默CDC25A基因后肝癌裸鼠移植瘤组织中差异表达基因的筛选

目的：探讨应用基因芯片技术筛选出可能受细胞分裂周期因子25A（cell division cycle 25A,CDC25A）调控的基因, 阐 明并验证CDC25A对肝癌相关基因的表达具有调控作用。方法：本课题组前期通过siRNA干扰技术沉默人肝癌HepG2细胞中 CDC25A的表达并成功构建了肝癌裸鼠移植瘤模型。基于上述研究成果,在本研究中应用Affymetrix基因表达谱芯片技术进一 步筛选沉默CDC25A后肝癌移植瘤组织中的差异表达基因,并进行GO及KEGG分析,应用qPCR对部分差异表达基因进行验 证。结果：通过芯片技术筛选出沉默CDC25A基因的肝癌移植组织中的差异表达基因188个,其中上调基因78个、下调基因110 个。这些差异表达基因主要涉及细胞增殖、细胞凋亡、蛋白复合物结合、细胞外间隙等方面,参与黏着斑、细胞外基质（extracellular matrix,ECM）受体相互作用等通路的改变。qPCR对部分差异表达基因验证的结果显示,HIPK2 mRNA表达上调,微纤丝关联 蛋白5（microfibrillar-associated protein 5,MFAP5）和细胞周期蛋白D1（cyclin D1,CCND1）mRNA表达下调,与芯片检测结果一 致。结论：应用人基因表达谱芯片技术成功筛选出沉默CDC25A后肝癌裸鼠移植瘤组织中的差异表达基因,为探究CDC25A影 响肝癌细胞生长提供了支持线索。