An association between clock genes and clock‐controlled cell cycle genes in murine colorectal tumors

Disruption of circadian machinery appears to be associated with the acceleration of tumor development. To evaluate the function of the circadian clock during neoplastic transformation, the daily profiles of the core clock genes Per1, Per2, Rev‐Erbα and Bmal1, the clock‐controlled gene Dbp and the clock‐controlled cell cycle genes Wee1, c‐Myc and p21 were detected by real‐time RT‐PCR in chemically induced primary colorectal tumors, the surrounding normal tissue and in the liver. The circadian rhythmicity of Per1, Per2, Rev‐Erbα and Dbp was significantly reduced in tumor compared with healthy colon and the rhythmicity of Bmal1 was completely abolished. Interestingly, the circadian expression of Per1, Per2, Rev‐Erbα and Dbp persisted in the colonic tissue surrounding the tumor but the rhythmic expression of Bmal1 was also abolished. Daily profiles of Wee1, c‐Myc and p21 did not exhibit any rhythmicity either in tumors or in the colon of healthy animals. The absence of diurnal rhythmicity of cell cycle genes was partially associated with ageing, because young healthy mice showed rhythmicity in the core clock genes as well as in the Wee1 and p21. In the liver of tumor‐bearing mice the clock gene rhythms were temporally shifted. The data suggest that the circadian regulation is distorted in colonic neoplastic tissue and that the gene‐specific disruption may be also observed in the non‐neoplastic tissues. These findings reinforce the role of peripheral circadian clockwork disruption for carcinogenesis and tumor progression.     

Expression of the Circadian Clock Genes Per1 and Per2 in Sporadic and Familial Breast Tumors

There is a growing body of evidence implicating aberrant circadian clock expression in the development of cancer. Based on our initial experiments identifying a putative interaction between BRCA1 and the clock proteins Per1 and Per2, as well as the reported involvement of the circadian clock in the development of cancer, we have performed an expression analysis of the circadian clock genes Per1 and Per2 in both sporadic and familial primary breast tumors and normal breast tissues using real-time polymerase chain reaction. Significantly decreased levels of Per1 were observed between sporadic tumors and normal samples (P < .00001), as well as a further significant decrease between familial and sporadic breast tumors for both Per1 (P < .00001) and Per2 (P < .00001). Decreased Per1 was also associated with estrogen receptor negativity (53% vs 15%, P = .04). These results suggest a role for both Per1 and Per2 in normal breast function and show for the first time that deregulation of the circadian clock may be an important factor in the development of familial breast cancer. Aberrant expression of circadian clock genes could have important consequences on the transactivation of downstream targets that control the cell cycle and on the ability of cells to undergo apoptosis, potentially promoting carcinogenesis.     

Impact of COX2 genotype,ER status and body constitution on risk of early events in different treatment groups of breast cancer patients

The COX2 rs5277 (306G>C) polymorphism has been associated with inflammation‐associated cancers. In breast cancer, tumor COX‐2 expression has been associated with increased estrogen levels in estrogen receptor (ER)‐positive and activated Akt‐pathway in ER‐negative tumors. Our study investigated the impact of COX2 genotypes on early breast cancer events and treatment response in relation to tumor ER status and body constitution. In Sweden, between 2002 and 2008, 634 primary breast cancer patients, aged 25–99 years, were included. Disease‐free survival was assessed for 570 rs5277‐genotyped patients. Body measurements and questionnaires were obtained preoperatively. Clinical data, patient‐ and tumor‐characteristics were obtained from questionnaires, patients' charts, population registries and pathology reports. Minor allele(C) frequency was 16.1%. Genotype was not linked to COX‐2 tumor expression. Median follow‐up was 5.1 years. G/G genotype was not associated with early events in patients with ER‐positive tumors, adjusted HR 0.77 (0.46–1.29), but conferred an over 4‐fold increased risk in patients with ER‐negative tumors, adjusted HR 4.41 (1.21–16.02)(p_interaction = 0.015). Chemotherapy‐treated G/G‐carriers with a breast volume ≥850 ml had an increased risk of early events irrespective of ER status, adjusted HR 8.99 (1.14–70.89). Endocrine‐treated C‐allele carriers with ER‐positive tumors and a breast volume ≥850 ml had increased risk of early events, adjusted HR 2.30 (1.12–4.75). COX2 genotype, body constitution and ER status had a combined effect on the risk of early events and treatment response. The high risk for early events in certain subgroups of patients suggests that COX2 genotype in combination with body measurements may identify patients in need of more personalized treatment.     

Down regulation of circadian clock gene Period 2 accelerates breast cancer growth by altering its daily growth rhythm

Purpose Per2, a core circadian clock gene, has tumor suppressor properties and is mutated or down regulated in human breast cancers. We have manipulated the expression of this gene in vitro and in vivo to more fully understand how the Per2 clock gene product affects cancer growth. Methods We used siRNA and shRNA to down regulate Per2 expression in vitro and in vivo and measured cancer cell proliferation, tumor growth rate and several molecular pathways relevant to cancer growth and their circadian organizations. All statistical tests were two-sided. Results Down regulation of functional Per2 gene expression increases Cyclin D and Cyclin E levels and doubles in vitro breast cancer cell proliferation (P < 0.05). Down regulation of Per2 also accelerates in vivo tumor growth and doubles the daily amplitude of the tumor growth rhythm (P < 0.05). Conclusions The clock gene Per2 exerts its tumor suppressor function in a circadian time dependent manner. Therefore, Per2 and perhaps other clock genes represent a new class of potential therapeutic targets whose manipulation will modulate cancer growth and cancer cell proliferation.     

Effects of supplemental calcium and vitamin D on tight‐junction proteins and mucin‐12 expression in the normal rectal mucosa of colorectal adenoma patients

The physical gut barrier, comprised of a thick mucus layer and the epithelium, plays an important role in defense against microbes and foreign antigens. Calcium and vitamin D may be involved in maintaining the integrity of the intestinal mucosal barrier, the dysfunction of which may lead to endotoxemia and inflammation, and contribute to colorectal carcinogenesis. We investigated supplemental calcium (1200 mg, daily) and/or vitamin D₃ (1000 IU daily) effects on intestinal barrier function‐related biomarkers in a subset of 105 participants from a large colorectal adenoma recurrence chemoprevention clinical trial. We assessed expression of the tight junction proteins claudin‐1 (CLDN1), occludin (OCLD), and mucin‐12 (MUC12) in the normal‐appearing colorectal mucosa using standardized, automated immunohistochemistry and quantitative image analysis. Following 1 year of treatment, in the calcium relative to the no calcium group, the CLDN1, OCLD, and MUC12 expression increased by 14% (P = 0.17), 23% (P = 0.11), and 22% (P = 0.07), respectively. In secondary analyses, the estimated calcium treatment effects were greater among participants with baseline serum 25‐OH‐vitamin D concentrations below the median value of 22.69 ng/mL (CLDN1: 29%, P = 0.04; OCLD: 36%, P = 0.06; MUC12: 35%, P = 0.05). There were no biomarker expression changes in the vitamin D₃ alone group; however, modest increases were found in the combined calcium/vitamin D₃ group. At baseline, obesity, history of a sessile‐serrated adenoma, colorectal MIB‐1/Ki‐67 expression, and a family history of colorectal cancer were associated with CLDN1, OCLD, and MUC12 expression. Our study supports continued investigation of factors that could affect intestinal mucosal barrier integrity relevant to colorectal carcinogenesis.     

Steroid receptor expression in thymomas and thymic carcinomas

BACKGROUND:

Although protein expressions of glucocorticoid receptor (GR), estrogen receptors (ERα and ERβ), progesterone receptor A (PgR‐A), and androgen receptor (AR) were shown to play roles in the growth and differentiation of normal thymus and thymic tumors, to the authors' knowledge their association with patient characteristics and prognosis has yet to be determined.

METHODS:

A series of 140 thymic epithelial tumors (57 type A + AB thymomas, 40 type B1 + B2 thymomas, 6 type B3 thymomas, and 37 thymic carcinomas) were examined for GR, ERα, ERβ, PgR‐A, and AR expression using immunohistochemistry. In addition, the correlation between expression of these hormone receptors and clinicopathologic factors and overall survival (OS) was assessed.

RESULTS:

GR and ERβ demonstrated a high rate of expression in thymomas and thymic carcinomas (82.9% and 76.4%, respectively), whereas rates of ERα, PgR‐A, and AR expression were low (13.6%, 0.71%, and 23.6%, respectively). A significant correlation (P < .05) was found between ERα expression and tumor size and between ERβ expression and tumor stage. Multivariate analyses revealed that histologic subtype (P = .0039), tumor stage (P = .0012), and GR expression (P = .0025) were significantly correlated with the 10‐year OS rate.

CONCLUSIONS:

GR and ERβ demonstrated high rates of expression in thymomas and thymic carcinomas. Furthermore, multivariate analysis revealed that GR expression was associated with better prognosis in patients with surgically resected thymomas and thymic carcinomas. Cancer 2011;. © 2011 American Cancer Society.     

DNA Repair Gene Patterns as Prognostic and Predictive Factors in Molecular Breast Cancer Subtypes

DNA repair pathways can enable tumor cells to survive DNA damage induced by chemotherapy and thus provide prognostic and/or predictive value. We evaluated Affymetrix gene expression profiles for 145 DNA repair genes in untreated breast cancer (BC) patients (n = 684) and BC patients treated with regimens containing neoadjuvant taxane/anthracycline (n = 294) or anthracycline (n = 210). We independently assessed estrogen receptor (ER)‐positive/HER2‐negative, HER2‐positive, and ER‐negative/HER2‐negative subgroups for differential expression, bimodal distribution, and the prognostic and predictive value of DNA repair gene expression. Twenty‐two genes were consistently overexpressed in ER‐negative tumors, and five genes were overexpressed in ER‐positive tumors, but no differences in expression were associated with HER2 status. In ER‐positive/HER2‐negative tumors, the expression of nine genes (BUB1, FANCI, MNAT1, PARP2, PCNA, POLQ, RPA3, TOP2A, and UBE2V2) was associated with poor prognosis, and the expression of one gene (ATM) was associated with good prognosis. Furthermore, the prognostic value of specific genes did not correlate with proliferation. A few genes were associated with chemotherapy response in BC subtypes and treatment‐specific manner. In ER‐negative/HER2‐negative tumors, the MSH2, MSH6, and FAN1 (previously MTMR15) genes were associated with pathological complete response and residual invasive cancer in taxane/anthracycline‐treated patients. Conversely, PMS2 expression was associated with residual invasive cancer in treatments using anthracycline as a single agent. In HER2‐positive tumors, TOP2A was associated with patient response to anthracyclines but not to taxane/anthracycline regimens. In genes expressed in a bimodal fashion, RECQL4 was significantly associated with clinical outcome. In vitro studies showed that defects in RECQL4 impair homologous recombination, sensitizing BC cells to DNA‐damaging agents.     

Hormone-receptor expression and activity of trastuzumab with chemotherapy in HER2-positive advanced breast cancer patients

BACKGROUND:

The relationship between quantitative immunohistochemical hormone receptor expression and response to the combination of trastuzumab with chemotherapy in HER2‐positive advanced breast cancer is currently unknown.

METHODS:

Estrogen receptor (ER) and progesterone receptor expression was studied both as a dichotomous variable (positivity set at ≥1% of positive cells) and as a continuous variable. The effect of hormone receptor expression on overall response rate and progression‐free survival in patients receiving trastuzumab‐based treatment was studied by univariate and multivariate analysis.

RESULTS:

One hundred eleven of 227 consecutive advanced breast cancer patients treated at 2 Institutions had hormone receptor‐positive tumors (49%). High expression of ER (≥30% of tumor cells) predicted reduced probability of tumor response to trastuzumab plus chemotherapy (multivariate odds ratio, 0.422; 95% confidence interval [CI], 0.222‐0.803; P = .009). In patients with hormone receptor‐positive tumors (≥1% of tumor cells), maintenance endocrine therapy added to trastuzumab upon the completion of chemotherapy was associated with a significant progression‐free survival benefit (hazard ratio, 0.521; 95% CI, 0.3325‐0.836; P = .007).

CONCLUSIONS:

Our results suggest a predictive role of hormone receptor expression in HER2‐positive tumors. Further investigation in this patient subset is warranted to optimize the use of HER2‐targeting agents, chemotherapy, and endocrine therapy. Cancer 2012;. © 2011 American Cancer Society.     

Response to primary chemotherapy in breast cancer patients with tumors not expressing estrogen and progesterone receptors

Background:We recently demonstrated that in premenopausalpatients with estrogen receptors (ER)-absent tumors, early initiation ofsystemic chemotherapy after primary surgery might improve outcome. These dataindicate a different responsiveness to chemotherapy for tumors not expressinghormone receptors. To test this hypothesis we evaluated the responsiveness topreoperative chemotherapy in patients with ER and progesterone receptors(PgR)-absent tumors. Patients and methods:Patients with biopsy-provenT₂–T₃, N_0–2 breast cancertreated at a single institution from January 1995 to August 1999 withpreoperative chemotherapy were retrospectively evaluated. ER and PgR weredetermined immunohistochemically and classified for this purpose as absent(0% of the cells positive) or positive (1% of the cells). Results:On 117 evaluable patients 72 had an objective response(61%). A significant difference in response was observed for patientswith ER and PgR absent compared with those with ER and/or PgR-positive tumors(82% vs. 57%,P = 0.03 Fishers's exact test).Pathological complete remission rates were also significantly different in thetwo groups (23% vs. 7%, respectively; P = 0.04). Conclusions:The different degree of response according to hormonereceptors expression supports the hypothesis that tumors not expressing bothER and PgR might represent a different clinical entity in terms ofchemotherapy responsiveness.     

Impact of low estrogen/progesterone receptor expression on survival outcomes in breast cancers previously classified as triple negative breast cancers

PURPOSE:

To evaluate the impact of low estrogen/progesterone receptor (ER/PR) expression and effect of endocrine therapy on survival outcomes in human epidermal growth factor receptor 2 (HER2)‐negative tumors with ER/PR <10%, previously labeled as triple negative.

METHODS:

In a retrospective review, 1257 patients were categorized according their ER/PR percentages into 3 groups, ER/PR <1% (group A), ER/PR 1% to 5% (group B), and ER/PR 6% to 10% (group C). Kaplan‐Meier product limit method was used to estimate survival outcomes. Cox proportional hazards models was used to adjust for patient and tumor characteristics.

RESULTS

Groups A, B, and C had 897 (71.4%), 241 (19.2%), and 119 (9.4%) patients, respectively. After a median follow‐up of 40 months there was no significant difference in 3‐year recurrence‐free survival (RFS): 64%, 67%, and 77% (P = .34) or overall survival (OS): 79%, 81%, and 88% (P = .33) for groups A, B, and C, respectively. ER/PR expression was not an independent predictor for RFS (hazard ratio [HR], 1.10; 95% confidence interval [CI], 0.86‐1.39; P = .46 for group B, and HR, 0.96; 95% CI, 0.66‐1.38; P = .81 for group C, compared with group A), or OS (HR, 1.11; 95% CI, 0.84‐1.46; P = .46 for group B, and HR, 0.94; 95% CI, 0.63‐1.42; P = .78 for group C, compared with group A). Endocrine therapy had no impact on survival outcomes (RFS: P = .10; OS: P = .45) among groups.

CONCLUSIONS:

In this cohort, a low ER/PR level (1%‐5%) does not appear to have any significant impact on survival outcomes. There was a tendency for survival advantages in the ER/PR 6% to 10% is seen. Benefit of endocrine therapy in these patients is unclear. Cancer 2011;. © 2011 American Cancer Society.     

Amplification of CyclinL1 in uterine cervical carcinoma has prognostic implications

The chromosomal 3q25.31 region was consistently amplified in primary cancer of cervix (CACX). CyclinL1 is a candidate gene of this region and already have been implicated as an oncogene in head and neck cancers. In this study, we aimed to investigate the involvement of CyclinL1 in cervical carcinogenesis and for this purpose its copy number variation (CNV) was studied in 23 cervical intraepithelial neoplasia (CIN) and 110 CACX samples. In CIN lesions CyclinL1 was not amplified; however, the amplification frequency was 16% (9/56) in stage I/II tumors which remained comparable during subsequent stages of tumorigenesis. This implied association of CyclinL1 amplification with development of early invasiveness. Quantitation of mRNA expression revealed 2.6 ± 1.53‐fold overexpression of this gene in primary CACX. The amplification/copy number gain of CyclinL1 and its mRNA profile were concordant, in tumors. Immunohistochemical (IHC) analysis in primary CACX, cell lines: SiHa and HeLa revealed intense nuclear expression of cyclinL1, which was further confirmed by Western blot in the cell lines. However 47% (7/15) CACX samples expressed high/intermediate level of cyclin L1. Kaplan–Meier survival analysis indicated CyclinL1 amplification as a determinant of poor patient outcome. Tumor radio‐resistance developed as a consequence of CyclinL1 amplification. Cox multivariate analysis revealed that multiparous (≥5) CACX patients with amplified CyclinL1 locus along with advanced tumor stage (III/IV) had worst prognosis. Our data suggest importance of CyclinL1 in cervical carcinogenesis with its associated pathways viz: pre‐mRNA splicing, cell‐cycle regulation (G₀/G₁ and G₂/M) being potential targets of therapeutic interventions in CACX. © 2010 Wiley‐Liss, Inc.     

Gender-related invasion differences associated with mRNA expression levels of melatonin membrane receptors in colorectal cancer

Melatonin inhibits growth and invasive capacity of colon cancer cells in vitro through its membrane (MT1 and MT2) and/or nuclear receptors (RORα). Previous studies showed that this indoleamine is present in both the normal and colon cancer at similar levels. Therefore, we analyzed MT1, MT2, and RORα expression in tumor samples versus normal mucosa (NM) from patients suffering from colorectal cancer (CRC). Given the existence of sex differences in the incidence and pathology of CRC and the involvement of steroid receptors in the oncostatic actions of melatonin in some types of cancer, we also analyzed the expression of androgen (AR) and estrogen receptor (ER) α and ERβ. Finally, we conducted some experiments in colon cancer cell lines to corroborate the experiments carried out in human tumors. We found a decreased expression of MT1, MT2, AR, ERα, and ERβ in tumor samples versus NM, but no changes in RORα expression in the whole cohort of patients. Classifying tumors by stage and gender, MT1, MT2, AR, ERα, and ERβ expression decreased in both early stage and advanced tumors, but only in male patients. On the other hand, MT1 and MT2 expression correlated positively with AR, ERα, and ERβ expression in male patients and with ERα or ERβ in female patients. In vitro, the invasive capacity was higher in cells with the least expression of MT1, MT2, and AR, and nonselective MT1/MT2 agonists inhibited cell growth and invasion. These results could indicate a possible interaction of these pathways.     

Expression of aldehyde dehydrogenase 1 as a marker of mammary stem cells in benign and malignant breast lesions of Ghanaian women

BACKGROUND:

Breast cancers that are negative for the estrogen receptor (ER), the progesterone receptor (PR), and the HER2 (human epidermal growth factor receptor 2) marker are more prevalent among African women, and the biologically aggressive nature of these triple‐negative breast cancers (TNBCs) may be attributed to their mammary stem cell features. Little is known about expression of the mammary stem cell marker aldehyde dehydrogenase 1 (ALDH1) in African women. Novel data are reported regarding ALDH1 expression in benign and cancerous breast tissue of Ghanaian women.

METHODS:

Formalin‐fixed, paraffin‐embedded specimens were transported from the Komfo Anoyke Teaching Hospital in Kumasi, Ghana to the University of Michigan for centralized histopathology study. Expression of ER, PR, HER2, and ALDH1 was assessed by immunohistochemistry. ALDH1 staining was further characterized by its presence in stromal versus epithelial and/or tumor components of tissue.

RESULTS:

A total of 173 women contributed to this study: 69 with benign breast conditions, mean age 24 years, and 104 with breast cancer, mean age 49 years. The proportion of benign breast conditions expressing stromal ALDH1 (n = 40, 58%) was significantly higher than those with cancer (n = 44, 42.3%) (P = .043). Among the cancers, TNBC had the highest prevalence of ALDH1 expression, either in stroma or in epithelial cells. More than 2‐fold higher likelihood of ALDH1 expression was observed in TNBC cases compared with other breast cancer subtypes (odds ratio = 2.38, 95% confidence interval 1.03‐5.52, P = .042).

CONCLUSIONS:

ALDH1 expression was higher in stromal components of benign compared with cancerous lesions. Of the ER‐, PR‐, and HER2‐defined subtypes of breast cancer, expression of ALDH1 was highest in TNBC. Cancer 2013. © 2012 American Cancer Society.     

Multiple mucin depleted foci,high proliferation and low apoptotic response in the onset of colon carcinogenesis of the PIRC rat,mutated in Apc

PIRC rats (F344/NTac‐Apc ^am1137) mutated in the Apc gene spontaneously develop colon tumors thus mimicking familial adenomatous polyposis (FAP) and sporadic colorectal cancer (CRC) more closely than Apc‐based rodent models developing tumors mostly in the small intestine. To understand whether microscopic dysplastic lesions precede the development of macroscopic tumors, PIRC rat colon was examined for the presence of mucin depleted foci (MDF), microadenomas of the rodent and human colon. Few MDF (about 4/animal) were already present in 1‐month‐old rats and their number rapidly increases to about 250 in 8‐month‐old rats. These lesions showed Wnt signaling activation (nuclear β‐catenin accumulation) and were dramatically decreased by sulindac (320 ppm), a drug with chemopreventive activity (MDF/rat at 4 months: 156 ± 8 and 38 ± 6 in controls and sulindac‐treated rats, respectively, means ± SE, p < 0.001). Since altered proliferation and apoptosis could underlie the early phases of carcinogenesis, we studied these processes in the apparently normal colon mucosa (NM) of 1‐month‐old PIRC and wt rats. Colon proliferation (PCNA expression) was significantly higher in PIRC rats. Notably, PIRC rat NM showed resistance to apoptosis since it sustained proliferation and had lower apoptosis after a cytotoxic insult with 1,2 dimethylhydrazine. Gene expression of Myc, p21, Birc5, Ogg1, Apex1 and Sod2 were significantly up‐regulated in the NM of PIRC rat. The overall results put forward PIRC rat as useful model of colon carcinogenesis, either to study the process itself or to test in vivo chemopreventive agents in both short‐ and long‐term studies.