Cyclin D1 expression is associated with poor prognostic features in estrogen receptor positive breast cancer

The overexpression of cyclin D1 is a positive prognostic factor in advanced-stage breast carcinoma cases

OBJECTIVE

Cyclin D1 (CDDN1) is a protein required for mitotic cell cycle progression through the G1 phase, as well as a regulatory component of the cyclin-dependent kinases CDK4 and CDK6. In this study, we wanted to evaluate the relationship between CDDN1 expression and clinicopathological features in breast cancer (BC) cases and whether CDDN1 could be used as a prognostic biomarker for BC cases.

METHODS

A total of 70 cases, 30 cases each with limited and advanced-stage BC, and as the control group, 10 healthy breast tissue, without a cancer diagnosis, with examined for benign reasons (mammoplasty, breast reduction surgery, etc.) were included in this study. The pathological specimens from the cases were stained, immunohistochemically, and categorized as a "low" (L) group or a "high" (H) group for CDDN1 expression. The cases' clinicopathological features and survival rates were evaluated statistically, within a 95% of confidence interval, p<0.05, retrospectively.

RESULTS

The median follow-up period of the cases was 48.00 (range, 6-150) months. CDDN1 expression was significantly higher in advanced-stage BC cases than in normal breast tissue and limited-stage BC cases. The median overall survival (OS) was 96 months (CI 95%: 67.74-117.59) in the H-CDDN1 group, compared to the L-CDDN1 group not reached, but there was no relation (p>0.05). CDDN1 overexpression was more prominent in low-grade advanced BC cases (p=0.004). The median OS of advanced-stage BC cases with Grade 1 was significantly longer than those with other grades (p=0.04).

CONCLUSION

Our results suggest that CDDN1 expression can be used as a potentially appropriate positive prognostic biomarker for advanced-stage BC cases.

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.

Prediction of Secondary and Tertiary Structure and Docking of Rb1WT And Rb1R661W Proteins

Background:

Retinoblastoma, a malignancy occurring in the juvenile cells of the retina, is responsible for light detection. It is one of the most emerging ra re childhood and infant cancer. It is initiated by the mutation in Rb1, a first tumor suppressor gene located on chromosome 13q14. Rb1 protein is responsible for cell cycle regulation.

Methods:

In our study, secondary and 3D-Structural predictions of Rb1WT and Rb1R661W were made by comparative or homology modeling to find any structural change leading to the disruption in its further interactions. Quality assurance of the structures was done by Ramachandran Plot for a stable structure. Both the proteins were then applied by docking process with proteins of interest.

Results:

Secondary structure showed a number of mutations in helixes, β-Hairpins of Rb1R661W. The major change was the loss of β-Hairpin loop, extension and shortening of helixes. 3D comparison structure showed a change in the groove of Rb1R661W. Docking results, unlike RB1 WT, had different and no interactions with some of the proteins of interest. This mutation in Rb1 protein had a deleterious effect on the protein functionality.

Conclusion:

This study will help to design the appropriate therapy and also understand the mechanism of disease of retinoblastoma, for researchers and pharmaceuticals.

Clinical Correlation and Role of Cyclin D1 Expression in Glioblastoma Patients: A Study From North India

Background/Aims Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor. Cyclin D1 is a protein that in humans is encoded by the CCND1 gene. Cyclin D1 protein is frequently overexpressed in malignant gliomas. Methods It is an observational study comprising 40 biopsy-proven cases of GBM in a span of one and half years. Immunohistochemistry (IHC) was used with Cyclin D1 monoclonal antibody. Cyclin D1 on the outcome was assessed using the Kaplan-Meier survival estimate and compared by log-rank test. Results Cyclin D1 was expressed in 60% of patients. The majority (72.5%) of patients expired during the study period, out of which 69% showed immune-expression in contrast to living subjects, out of which only 45.5% of patients exhibited expression. The maximum number of glioblastoma patients were aged between 41 and 50 years (40%), followed by those aged between 31 and 40 years (20%). The male to female ratio of study subjects was 3.44:1. Conclusion The study concluded that there is no significant association between Cyclin D1 expression status and different demographic, clinical, and outcome variables.

Prognostic and Predictive Value of CCND1/Cyclin D1 Amplification in Breast Cancer With a Focus on Postmenopausal Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Up to 80% of breast cancers (BCa) are estrogen receptor positive and current treatments target the estrogen receptor (endocrine therapies) and/or CDK4/6 (CDK4/6 inhibitors). CCND1 encodes the protein cyclin D1, responsible for regulation of G1 to S phase transition in the cell cycle. CCND1 amplification is common in BCa and contributes to increased cyclin D1 expression. As there are signalling interactions between cyclin D1 and the estrogen receptor, understanding the impact of CCND1 amplification on estrogen receptor positive patients' disease outcomes, is vital. This review aims to evaluate CCND1 amplification as a prognostic and predictive biomarker in BCa.

MATERIALS AND METHODS

Publications were retrieved from the databases: PubMed, MEDLINE, Embase and Cochrane library. Exclusion criteria were duplication, publication type, non-English language, in vitro and animal studies, not BCa, male BCa, premenopausal BCa, cohort size <35, CCND1 amplification not reported. Publications with cohort duplication, and inadequate recurrence free survival (RFS) and overall survival (OS) data, were also excluded. Included publications were assessed for Risk of Bias (RoB) using the Quality In Prognosis Studies tool. Statistical analyses (Inverse Variance and Mantel-Haenszel) were performed in Review Manager. The PROSPERO registration number is [CRD42020208179].

RESULTS

CCND1 amplification was significantly associated with positive estrogen receptor status (OR:1.70, 95% CI:1.19-2.43, p = 0.004) and cyclin D1 overexpression (OR: 5.64, 95% CI: 2.32-13.74, p=0.0001). CCND1 amplification was significantly associated with shorter RFS (OR: 1.64, 95% CI: 1.13-2.38, p = 0.009), and OS (OR: 1.51, 95% CI: 1.19-1.92, p = 0.0008) after removal of studies with a high RoB. In endocrine therapy treated patients specifically, CCND1 amplification predicted shorter RFS (HR: 2.59, 95% CI: 1.96-3.41, p < 0.00001) and OS (HR: 1.59, 95% CI: 1.00-2.49, p = 0.05) also after removal of studies with a high RoB.

CONCLUSION

While a lack of standardised approach for the detection of CCND1 amplification is to be considered as a limitation, CCND1 amplification was found to be prognostic of shorter RFS and OS in BCa. CCND1 amplification is also predictive of reduced RFS and OS in endocrine therapy treated patients specifically. With standardised methods and cut offs for the detection of CCND1 amplification, CCND1 amplification would have potential as a predictive biomarker in breast cancer patients.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier CRD42020208179.

Single Cell Genetic Profiling of Tumors of Breast Cancer Patients Aged 50 Years and Older Reveals Enormous Intratumor Heterogeneity Independent of Individual Prognosis

PURPOSE

Older breast cancer patients are underrepresented in cancer research even though the majority (81.4%) of women dying of breast cancer are 55 years and older. Here we study a common phenomenon observed in breast cancer which is a large inter- and intratumor heterogeneity; this poses a tremendous clinical challenge, for example with respect to treatment stratification. To further elucidate genomic instability and tumor heterogeneity in older patients, we analyzed the genetic aberration profiles of 39 breast cancer patients aged 50 years and older (median 67 years) with either short (median 2.4 years) or long survival (median 19 years). The analysis was based on copy number enumeration of eight breast cancer-associated genes using multiplex interphase fluorescence in situ hybridization (miFISH) of single cells, and by targeted next-generation sequencing of 563 cancer-related genes.

RESULTS

We detected enormous inter- and intratumor heterogeneity, yet maintenance of common cancer gene mutations and breast cancer specific chromosomal gains and losses. The gain of COX2 was most common (72%), followed by MYC (69%); losses were most prevalent for CDH1 (74%) and TP53 (69%). The degree of intratumor heterogeneity did not correlate with disease outcome. Comparing the miFISH results of diploid with aneuploid tumor samples significant differences were found: aneuploid tumors showed significantly higher average signal numbers, copy number alterations (CNAs) and instability indices. Mutations in PIKC3A were mostly restricted to luminal A tumors. Furthermore, a significant co-occurrence of CNAs of DBC2/MYC, HER2/DBC2 and HER2/TP53 and mutual exclusivity of CNAs of HER2 and PIK3CA mutations and CNAs of CCND1 and PIK3CA mutations were revealed.

CONCLUSION

Our results provide a comprehensive picture of genome instability profiles with a large variety of inter- and intratumor heterogeneity in breast cancer patients aged 50 years and older. In most cases, the distribution of chromosomal aneuploidies was consistent with previous results; however, striking exceptions, such as tumors driven by exclusive loss of chromosomes, were identified.

The prognostic value of cyclin D1 in breast cancer patients treated with hormonal therapy: A pilot study

THE AIM

of the study was to determine the clinical relevance of cyclin D1 (cD1) and its association with clinicopathological parameters in breast cancer patients treated with hormonal therapy.

MATERIAL AND METHODS

The study included 96 primary breast cancer patients with known clinicopathological parameters. In adjuvant setting, 44 patients were tamoxifen-treated and 52 were treated with ovarian irradiation/ablation. The cD1 status (gene amplified/nonamplified) was determined on formalin-fixed paraffin-embedded tumor tissue sections by chromogenic in situ hybridization. Associations between parameters were analyzed by Chi-square and Spearman's rank order correlation tests. Cox proportional hazards regression test was performed. Survival curves for relapse-free survival were constructed according to the Kaplan-Meier method.

RESULTS

There were no significant associations between cyclin D1 and clinicopathological parameters in either patient group. Amplified cyclin D1 associated significantly with the actual relapse incidence in the ovarian ablation patient group (p = 0.01, HR = 3.1), but not in the tamoxifen-treated patient group. Estrogen receptor and cyclin D1 have proven to be independent parameters of poor outcome in the ovarian ablation patient group (p = 0.03, HR = 2.9; and p = 0.009, HR = 2.5; respectively).

CONCLUSIONS

Cyclin D1 might be a candidate biomarker of poor outcome in breast cancer patients treated with ovarian ablation, suggesting its possible involvement in acquirement of hormonal resistance. The role of cyclin D1 as potential parameter of response to tamoxifen was not as pronounced.

Biomarkers in Breast Cancer: An Integrated Analysis of Comprehensive Genomic Profiling and PD-L1 Immunohistochemistry Biomarkers in 312 Patients with Breast Cancer

BACKGROUND

We examined the current biomarker landscape in breast cancer when programmed death-ligand 1 (PD-L1) testing is integrated with comprehensive genomic profiling (CGP).

MATERIAL AND METHODS

We analyzed data from samples of 312 consecutive patients with breast carcinoma tested with both CGP and PD-L1 (SP142) immunohistochemistry (IHC) during routine clinical care. These samples were stratified into hormone receptor positive (HR+)/human epidermal growth factor receptor negative (HER2-; n = 159), HER2-positive (n = 32), and triple-negative breast cancer (TNBC) cohorts (n = 121).

RESULTS

We found that in the TNBC cohort, 43% (52/121) were immunocyte PD-L1-positive, and in the HR+/HER2- cohort, 30% (48/159) had PIK3CA companion diagnostics mutations, and hence were potentially eligible for atezolizumab plus nab-paclitaxel or alpelisib plus fulvestrant, respectively. Of the remaining 212 patients, 10.4% (22/212) had a BRCA1/2 mutation, which, if confirmed by germline testing, would allow olaparib plus talazoparib therapy. Of the remaining 190 patients, 169 (88.9%) were positive for another therapy-associated marker or a marker that would potentially qualify the patient for a clinical trial. In addition, we examined the relationship between immunocyte PD-L1 positivity and different tumor mutation burden (TMB) cutoffs and found that when a TMB cutoff of ≥9 mutations per Mb was applied (cutoff determined based on prior publication), 11.6% (14/121) patients were TMB ≥9 mutations/Mb and of these, TMB ≥9 mutations per Mb, 71.4% (10/14) were also positive for PD-L1 IHC.

CONCLUSION

Our integrated PD-L1 and CGP methodology identified 32% of the tested patients as potentially eligible for at least one of the two new Food and Drug Administration approved therapies, atezolizumab or alpelisib, and an additional 61.2% (191/312) had other biomarker-guided potential therapeutic options.

IMPLICATIONS FOR PRACTICE

This integrated programmed death-ligand 1 immunohistochemistry and comprehensive genomic profiling methodology identified 32% of the tested patients as eligible for at least one of the two new Food and Drug Administration-approved therapies, atezolizumab or alpelisib, and an additional 61.2% (191/312) had other biomarker-guided potential therapeutic options. These findings suggest new research opportunities to evaluate the predictive utility of other commonly seen PIK3CA mutations in hormone receptor-positive breast cancers and to standardize tumor mutation burden cutoffs to evaluate its potentially predictive role in triple-negative breast cancer.

A review of clinical and emerging biomarkers for breast cancers: towards precision medicine for patients

Background:

Breast cancer is the most commonly diagnosed malignancy among women and accounts for about 25% of all new cancer cases and 13% of all cancer deaths in Canadian women. It is a highly heterogeneous disease, encompassing multiple tumour entities, each characterised by distinct morphology, behaviour and clinical implications. Moreover, different breast tumour subtypes have different risk factors, clinical presentation, histopathological features, outcome and response to systemic therapies. Therefore, any strategies capable of the stratification of breast cancer by clinically relevant subtypes are an important requirement for personalised and targeted treatment. Therefore, in the advancement towards the concept of precision medicine that takes individual patient variability into account, several investigators have focused on the identification of effective clinical breast cancer biomarkers that interrogate key aberrant pathways potentially targetable with molecular targeted or immunological therapies.

Methods and materials:

This paper reports on a review of 11 current clinical and emerging biomarkers used in screening for early detection and diagnosis, to stratify patients by disease subtype, to identify patients’ risk for metastatic disease and subsequent relapse, to monitor patient response to specific treatment and to provide clinicians the possibility of prospectively identifying groups of patients who will benefit from a particular treatment.

Conclusion:

The future holds promising for the use of effective clinical breast cancer biomarkers for early detection and personalised patient-specific targeted treatment and increased patient survival. Breast cancer biomarkers can potentially assist in early-staged, non-invasive, sensitive and specific breast cancer detection and screening, provide clinically useful information for identification of patients with a greater likelihood of benefiting from the specific treatment, offer a better understanding of the metastatic process in cancer patients, predict disease and for patients with the established disease can assist define the nature of the disease, monitor the success of treatment and guide the clinical management of the disease.

A tetraprenylated benzophenone 7-epiclusianone induces cell cycle arrest at G1/S transition by modulating critical regulators of cell cycle in breast cancer cell lines

Breast cancer is a complex disease and encompassing different types of tumor. Although advances in understanding of the molecular bases of breast cancer biology, the therapeutic proposals available still are not effective. In this scenario, the present study aimed to evaluate the mechanisms associated to antitumor activity of 7-Epiclusianone (7-Epi), a tetraprenylated benzophenone, on luminal A (MCF-7) and claudin-low (Hs 578T) breast cancer cell lines. We found that 7-Epi efficiently inhibited cell proliferation and migration of these cells; however MCF-7 was slightly more responsive than Hs 578T. Cell cycle analysis showed accumulation of cells at G0/G1 phase with drastic reduction of S population in treated cultures. This effect was associated to downregulation of CDKN1A (p21) and cyclin E in both cell lines. In addition, 7-Epi reduced cyclin D1 and p-ERK expression levels in MCF-7 cell line. Cytotoxic effect of 7-Epi on breast cancer cell lines was associated to its ability to increase BAX/BCL-2 ratio. In conclusion, our findings showed that 7-Epi is a promising antitumor agent against breast cancer by modulating critical regulators of the cell cycle and apoptosis.

High Levels of Chromosomal Copy Number Alterations and TP53 Mutations Correlate with Poor Outcome in Younger Breast Cancer Patients

Prognosis in young patients with breast cancer is generally poor, yet considerable differences in clinical outcomes between individual patients exist. To understand the genetic basis of the disparate clinical courses, tumors were collected from 34 younger women, 17 with good and 17 with poor outcomes, as determined by disease-specific survival during a follow-up period of 17 years. The clinicopathologic parameters of the tumors were complemented with DNA image cytometry profiles, enumeration of copy numbers of eight breast cancer genes by multicolor fluorescence in situ hybridization, and targeted sequence analysis of 563 cancer genes. Both groups included diploid and aneuploid tumors. The degree of intratumor heterogeneity was significantly higher in aneuploid versus diploid cases, and so were gains of the oncogenes MYC and ZNF217. Significantly more copy number alterations were observed in the group with poor outcome. Almost all tumors in the group with long survival were classified as luminal A, whereas triple-negative tumors predominantly occurred in the short survival group. Mutations in PIK3CA were more common in the group with good outcome, whereas TP53 mutations were more frequent in patients with poor outcomes. This study shows that TP53 mutations and the extent of genomic imbalances are associated with poor outcome in younger breast cancer patients and thus emphasize the central role of genomic instability vis-a-vis tumor aggressiveness.

Calcineurin regulates cyclin D1 stability through dephosphorylation at T286

The Calcineurin/NFAT (nuclear factor of activated T cells) pathway plays an essential role in the tumorigenic and metastatic properties in breast cancer. The molecular mechanism of the antiproliferative effect of calcineurin inhibition, however, is poorly understood. We found that calcineurin inhibition delayed cell cycle progression at G1/S, and promoted cyclin D1 degradation by inhibiting dephosphorylation at T286. Importantly, overexpression of cyclin D1 partially rescued delayed G1/S progression, thereby revealing cyclin D1 as a key factor downstream of calcineurin inhibition. Cyclin D1 upregulation is observed in human invasive breast cancers, and our findings indicate that dysregulation of T286 phosphorylation could play a role in this phenomenon. We therefore propose that targeting site specific phosphorylation of cyclin D1 could be a potential strategy for clinical intervention of invasive breast cancer.

Progesterone Receptor B signaling Reduces Breast Cancer Cell Aggressiveness: Role of Cyclin-D1/Cdk4 Mediating Paxillin Phosphorylation

Progesterone-Receptor (PR) positivity is related with an enhanced response to breast cancer therapy, conversely cyclin D1 (CD1) is a retained marker of poor outcome. Herein, we demonstrate that hydroxyprogesterone (OHPg) through progesterone receptor B (PR-B) reduces breast cancer cell aggressiveness, by targeting the cytoplasmic CD1. Specifically, OHPg diminishes CD1 expression by a transcriptional regulation due to the recruitment of PR-B at a canonical half-PRE site of the CD1 promoter, together with HDAC1, determining a chromatin conformation less prone for gene transcription. CD1, together with its kinase partner Cdk4, regulates cell migration and metastasis, through the association with key components of focal adhesion, such as Paxillin (Pxn). Kaplan-Meier analysis shows that low Pxn expression was associated with increased distant metastasis-free survival in luminal A PR+ breast carcinomas. Interestingly, OHPg treatment reduced Pxn content in T47-D and MCF-7 cells; besides, the interaction between endogenous cytoplasmic CD1/Cdk4 with Pxn was reduced. This was consistent with the reduction of p-Ser83Pxn levels, crucially causing the delay in cell migration and a concomitant inhibition of Rac1 activity and p-PAK. Collectively, these findings support the role of PR-B in breast epithelial cell integrity and reinforce the importance in targeting PR-B as a potential strategy to restrict breast tumor cell invasion and metastasis.

An Immunohistochemical Study of Cyclin D1 Expression in Astrocytic Tumors and its Correlation with Tumor Grade

Background & Objective:

Glioblastoma-multiforme is the high grade form of astrocytic tumors with a short survival time, which are the most common type of brain tumors. Therefore, finding new therapeutic options is essential. Cyclin D1 is expressed in some human malignancies and can be a potential target for therapeutic intervention. The aim of the present study was to determine this relationship.

Methods:

This is a cross-sectional study conducted in the pathology department of Al-Zahra Hospital in Isfahan, Iran. In this study, 100 samples diagnosed with astrocytic tumors between 2011 and 2015 that met the study’s requirements were studied and immunohistochemical staining for cyclin D1 was performed for each specimen. At the end, the relationship between the expression of cyclin D1 and various variables including tumor grades, tumor subtypes and patient demographic features were examined using appropriate statistical tests.

Results:

Of the 100 samples, cyclin D1 was positive in 60 samples and negative in 40 samples. Moreover, in 26 samples, the amount of the marker was low, while in 34 samples it was high. Following the results of the study, there was a significant difference (P =0.038) in the expression of the cyclin D1 marker among the four different grades of astrocytic tumors.

Conclusion:

The results showed that the expression of cyclin D1 was associated with different tumor grades, especially the high level of expression in grade 4, and the amount of cyclin D1 increased as the level of grade glioma increased.

Family history influences the tumor characteristics and prognosis of breast cancers developing during postmenopausal hormone therapy

Long term use of postmenopausal hormone therapy (HT) has been reported to increase breast cancer risk. On the other hand, observational studies suggest that breast cancers diagnosed during HT may have a more favorable prognosis. While family history is a risk factor for breast cancer, and genetic factors also influence prognosis, the role of family history in combination with HT use has been little studied. We investigated the relationship between HT, family history, and prognosis in 584 (267 exposed) familial and 952 (460 exposed) non-familial breast cancer cases, using three survival end points: death from breast cancer (BCS), distant disease free survival (DDFS), and local recurrence free survival (LRFS). Among non-familial cases, HT was associated with better BCS (HR 0.63, 95% CI 0.41-0.94; p = 0.025), and DDFS (HR 0.58, 95% CI 0.40-0.85; p = 0.005), with a consistent but not statistically significant effect in LRFS. This effect was not seen in familial cases (HR > 1.0), and family history was found to interact with HT in BCS (p_{(interaction)} = 0.0067) (BC-death) and DDFS (p_{(interaction)} = 0.0070). There was phenotypic heterogeneity between HT-associated tumors in familial and non-familial cases, particularly on estrogen receptor (ER) status, although the interaction between HT and family history appears to be at least partially independent of these markers (p = 0.0370 after adjustment for standard prognostic factors). If confirmed by further studies, our results suggest that family history should be taken into consideration in clinical counseling before beginning a HT regimen.

Meta-analysis of three genome-wide association studies identifies two loci that predict survival and treatment outcome in breast cancer

The majority of breast cancers are driven by the female hormone oestrogen via oestrogen receptor (ER) alpha. ER-positive patients are commonly treated with adjuvant endocrine therapy, however, resistance is a common occurrence and aside from ER-status, no unequivocal predictive biomarkers are currently in clinical use. In this study, we aimed to identify constitutional genetic variants influencing breast cancer survival among ER-positive patients and specifically, among endocrine-treated patients. We conducted a meta-analysis of three genome-wide association studies comprising in total 3,136 patients with ER-positive breast cancer of which 2,751 had received adjuvant endocrine therapy. We identified a novel locus (rs992531 at 8p21.2) associated with reduced survival among the patients with ER-positive breast cancer (P = 3.77 × 10-8). Another locus (rs7701292 at 5q21.3) was associated with reduced survival among the endocrine-treated patients (P = 2.13 × 10-8). Interaction analysis indicated that the survival association of rs7701292 is treatment-specific and independent of conventional prognostic markers. In silico functional studies suggest plausible biological mechanisms for the observed survival associations and a functional link between the putative target genes of the rs992531 and rs7701292 (RHOBTB2 and RAB9P1, respectively). We further explored the genetic interaction between rs992531 and rs7701292 and found a significant, treatment-specific interactive effect on survival among ER-positive, endocrine-treated patients (hazard ratio = 6.97; 95% confidence interval, 1.79-27.08, Pinteraction= 0.036). This is the first study to identify a genetic interaction that specifically predicts treatment outcome. These findings may provide predictive biomarkers based on germ line genotype informing more personalized treatment selection.

Transcription activated p73-modulated cyclin D1 expression leads to doxorubicin resistance in gastric cancer

Gastric cancer (GC) is one of the leading types of cancer in terms of mortality cases worldwide. Doxorubicin (Dox), a common chemotherapy drug, is frequently used to treat GC; however, acquired resistance to Dox hinders the chemotherapeutic outcome and causes shorter survival in GC patients. Several Dox-resistant GC cell lines, including SGC7901, SNU-1 and SNU-5 were generated to investigate the mechanism of Dox resistance in GC. Various methods were used to test the response of Dox-resistant GC cells and parental cells, including flow cytometry, Cell Counting kit-8 assay, reverse transcription polymerase chain reaction and western blot analysis. In the present study, various Dox-resistant cells presented reduced apoptosis and cell cycle arrest in response to Dox treatment. Western blot results revealed that cyclin D1 was upregulated in Dox-resistant cells, whereas inhibition or depletion of cyclin D1 re-sensitized the resistant cells to Dox treatment, which indicated that the induction of cyclin D1 expression was a result of the Dox resistance in GC cells. Furthermore, it was observed that a transcription activated form of p73 (TAp73), is the upstream modulator of cyclin D1, manipulating the cyclin D1 transcription with the assistance of activator protein 1 (AP-1). Overall, the present study data provided a rational strategy to overcome the Dox resistance in GC treatment by inhibiting cyclin D1 expression.

microRNA Expression in Ethnic Specific Early Stage Breast Cancer: an Integration and Comparative Analysis

Breast cancer (BC) has a higher incidence in young Lebanese woman as compared to the West. We assessed the microRNA (miRNA) microarray profile of tissues derived from Lebanese patients with early BC and performed mRNA-miRNA integration analysis. 173 miRNAs were significantly dysregulated in 45 BC versus 17 normal adjacent breast tissues, including 74 with a fold change more than two of which 17 were never reported before in cancer. Integration analysis of mRNA-miRNA microarray data revealed a potential role of 51 dysregulated miRNA regulating 719 tumor suppressive or oncogenic mRNA associated with increased proliferation and decreased migration and invasion. We then performed a comparative miRNA microarray profile analysis of BC tissue between these 45 Lebanese and 197 matched American BC patients. Notably, Lebanese BC patients had 21 exclusively dysregulated miRNA (e.g. miR-31, 362-3p, and 663) and 4 miRNA with different expression manner compared to American patients (e.g. miR-1288-star and 324-3p). Some of these differences could reflect variation in patient age at diagnosis or ethnic variation affecting miRNA epigenetic regulation or sequence of miRNA precursors. Our data provide a basis for genetic/epigenetic investigations to explore the role of miRNA in early stage BC in young women, including ethnic specific differences.

Prognostic significance of cyclin D1 protein expression and gene amplification in invasive breast carcinoma

The oncogenic capacity of cyclin D1 has long been established in breast cancer. CCND1 amplification has been identified in a subset of patients with poor prognosis, but there are conflicting data regarding the predictive value of cyclin D1 protein overexpression. This study was designed to analyze the expression of cyclin D1 and its correlation with CCND1 amplification and their prognostic implications in invasive breast cancer. By using the tissue microarray technique, we performed an immunohistochemical study of ER, PR, HER2, p53, cyclin D1, Ki67 and p16 in 179 invasive breast carcinoma cases. The FISH method was performed to detect HER2/Neu and CCND1 amplification. High cyclin D1 expression was identified in 94/179 (52%) of invasive breast cancers. Cyclin D1 overexpression and CCND1 amplification were significantly associated (p = 0.010). Overexpression of cyclin D1 correlated with ER expression, PR expression and Luminal subtypes (p<0.001), with a favorable impact on overall survival in the whole series. However, in the Luminal A group, high expression of cyclin D1 correlated with shorter disease-free survival, suggesting that the prognostic role of cyclin D1 depends on the molecular subtype. CCND1 gene amplification was detected in 17 cases (9%) and correlated significantly with high tumor grade (p = 0.038), high Ki-67 protein expression (p = 0.002), and the Luminal B subtype (p = 0.002). Patients with tumors with high amplification of CCND1 had an increased risk of recurrence (HR = 2.5; 95% CI, 1.2-4.9, p = 0.01). These findings suggest that CCND1 amplification could be useful for predicting recurrence in invasive breast cancer.

High expression of cyclin D1 is associated to high proliferation rate and increased risk of mortality in women with ER-positive but not in ER-negative breast cancers

Purpose

Cyclin D1 has a central role in cell cycle control and is an important component of estrogen regulation of cell cycle progression. We have previously shown that high cyclin D expression is related to aggressive features of ER-positive but not ER-negative breast cancer. The aims of the present study were to validate this differential ER-related effect and furthermore explore the relationship between cyclin D overexpression and CCND1 gene amplification status in a node-negative breast cancer case–control study.

Methods

Immunohistochemical nuclear expression of cyclin D1 (n = 364) and amplification of the gene CCND1 by fluorescent in situ hybridization (n = 255) was performed on tissue microarray sections from patients with T1-2N0M0 breast cancer. Patients given adjuvant chemotherapy were excluded. The primary event was defined as breast cancer death. Breast cancer-specific survival was analyzed in univariate and multivariable models using conditional logistic regression.

Results

Expression of cyclin D1 above the median (61.7%) in ER breast cancer was associated with an increased risk for breast cancer death (OR 3.2 95% CI 1.5–6.8) also when adjusted for tumor size and grade (OR 3.1). No significant prognostic impact of cyclin D1 expression was found among ER-negative cases. Cyclin D1 overexpression was significantly associated to high expression of the proliferation markers cyclins A (ρ 0.19, p = 0.006) and B (ρ 0.18, p = 0.003) in ER-positive tumors, but not in ER-negative cases. There was a significant association between CCND1 amplification and cyclin D1 expression (p = 0.003), but CCND1 amplification was not statistically significantly prognostic (HR 1.4, 95% CI 0.4–4.4).

Conclusion

We confirmed our previous observation that high cyclin D1 expression is associated to high proliferation and a threefold higher risk of death from breast cancer in ER-positive breast cancer.

Cell Cycle Protein Expression in Neuroendocrine Tumors: Association of CDK4/CDK6, CCND1, and Phosphorylated Retinoblastoma Protein With Proliferative Index

OBJECTIVES

Dysregulation of the cell cycle has been observed and implicated as an etiologic factor in a range of human malignancies, but remains relatively unstudied in neuroendocrine tumors (NETs). We evaluated expression of key proteins involved in cell cycle regulation in a large cohort of NETs.

METHODS

We evaluated immunohistochemical expression of CDKN1B, CDKN1A, CDKN2A, CDK2, CDK4, CDK6, cyclin D1, cyclin E1, and phosphorylated retinoblastoma protein (phospho-RB1) in a cohort of 267 patients with NETs. We then explored associations between cell cycle protein expression, mutational status, histologic features, and overall survival.

RESULTS

We found that high expression of CDK4, CDK6, CCND1, and phospho-RB1 was associated with higher proliferative index, as defined by MKI67. We additionally observed a trend toward shorter overall survival associated with low expression of CDKN1B. This association seemed strongest in SINETs (multivariate hazards ratio, 2.04; 95% confidence interval, 1.06-3.93; P = 0.03). We found no clear association between CDKN1B mutation and protein expression.

CONCLUSIONS

Our results suggest that dysregulation and activation of the CDK4/CDK6-CCND1-phospho-RB1 axis is associated with higher proliferative index in NETs. Investigation of the therapeutic potential of CDK4/CDK6 inhibitors in higher grade NETs is warranted.

RNAi-mediated downregulation of cyclin Y to attenuate human breast cancer cell growth

Cyclin Y (CCNY) is a newly identified PFTK1 interacting protein and has been found to be associated with the proliferation and tumorigenesis of human non-small cell lung cancer. In the present study, we analyzed the expression levels of CCNY in 65 cases of breast cancer (BC) tissues and in four BC cell lines, BT-474, MDA-MB-231, T-47D and MCF-7. Lentivirus-mediated short hairpin RNA (shRNA) was employed to knock down CCNY expression in MCF-7 and MDA-MB-231 cells. The effects of CCNY depletion on cell growth were examined by MTT, colony formation and flow cytometry assays. The results showed that immunohistochemical expression of CCNY in tumor tissues is stronger than that in normal tissues. CCNY was also expressed in all four BC cells. The knockdown of CCNY resulted in a significant reduction in cell proliferation and colony formation ability. Cell cycle analysis showed that CCNY knockdown arrested MDA-MB‑231 cells in the G0/G1 phase. Furthermore, depletion of CCNY inhibited BC cell growth via the activation of Bad and GSK3β, as well as cleavages of PARP and caspase-3 in a p53-dependent manner. Therefore, we believe that CCNY has biological effect in BC development, and its inhibition via an RNA interference lentiviral system may provide a therapeutic option for BC.

No difference in CCND1 gene expression between breast cancer patients with and without lymph node metastasis in a Southern Brazilian sample

The Cyclin D1 protein has been extensively studied over the last decades, for its various roles in physiological processes, both in normal and cancer cells. Gene amplifications and overexpression of CCND1 are frequently reported in several types of cancers, including breast carcinomas, showing the increasing relevance of Cyclin D1 in tumorigenesis. Little is known about the role of this protein in the metastatic process, and the main objective of this study was to evaluate the importance of the CCND1 as a potential marker of tumor progression in breast carcinomas, in a sample collected in Southern Brazil. We studied 41 samples of formalin-fixed paraffin-embedded tissue sections from invasive ductal breast carcinomas subdivided into metastatic (n = 19) and non-metastatic (n = 22) tumors. Gene expression analysis was performed through Quantitative Real-Time PCR and immunohistochemistry. In spite of the higher expression levels of CCND1 mRNA and protein in tumors when compared with the control samples, no differences were observed between the metastatic and non-metastatic groups, suggesting that, in these samples, the expression of CCND1 has no significant influence on the metastatic process. Further studies must be performed in an attempt to clarify the diagnostic and prognostic value of Cyclin D1 in breast cancers, as well as the mechanisms that trigger its overexpression in tumors.

Role of RUNX2 in Breast Carcinogenesis

RUNX2 is a transcription factor playing the major role in osteogenesis, but it can be involved in DNA damage response, which is crucial for cancer transformation. RUNX2 can interact with cell cycle regulators: cyclin-dependent kinases, pRB and p21Cip1 proteins, as well as the master regulator of the cell cycle, the p53 tumor suppressor. RUNX2 is involved in many signaling pathways, including those important for estrogen signaling, which, in turn, are significant for breast carcinogenesis. RUNX2 can promote breast cancer development through Wnt and Tgfβ signaling pathways, especially in estrogen receptor (ER)-negative cases. ERα interacts directly with RUNX2 and regulates its activity. Moreover, the ERα gene has a RUNX2 binding site within its promoter. RUNX2 stimulates the expression of aromatase, an estrogen producing enzyme, increasing the level of estrogens, which in turn stimulate cell proliferation and replication errors, which can be turned into carcinogenic mutations. Exploring the role of RUNX2 in the pathogenesis of breast cancer can lead to revealing new therapeutic targets.

S6 kinase signaling: tamoxifen response and prognostic indication in two breast cancer cohorts

Detection of signals in the mammalian target of rapamycin (mTOR) and the estrogen receptor (ER) pathways may be a future clinical tool for the prediction of adjuvant treatment response in primary breast cancer. Using immunohistological staining, we investigated the value of the mTOR targets p70-S6 kinase (S6K) 1 and 2 as biomarkers for tamoxifen benefit in two independent clinical trials comparing adjuvant tamoxifen with no tamoxifen or 5 years versus 2 years of tamoxifen treatment. In addition, the prognostic value of the S6Ks was evaluated. We found that S6K1 correlated with proliferation, HER2 status, and cytoplasmic AKT activity, whereas high protein expression levels of S6K2 and phosphorylated (p) S6K were more common in ER-positive, and low-proliferative tumors with pAKT-s473 localized to the nucelus. Nuclear accumulation of S6K1 was indicative of a reduced tamoxifen effect (hazard ratio (HR): 1.07, 95% CI: 0.53-2.81, P=0.84), compared with a significant benefit from tamoxifen treatment in patients without tumor S6K1 nuclear accumulation (HR: 0.42, 95% CI: 0.29-0.62, P<0.00001). Also S6K1 and S6K2 activation, indicated by pS6K-t389 expression, was associated with low benefit from tamoxifen (HR: 0.97, 95% CI: 0.50-1.87, P=0.92). In addition, high protein expression of S6K1, independent of localization, predicted worse prognosis in a multivariate analysis, P=0.00041 (cytoplasm), P=0.016 (nucleus). In conclusion, the mTOR-activated kinases S6K1 and S6K2 interfere with proliferation and response to tamoxifen. Monitoring their activity and intracellular localization may provide biomarkers for breast cancer treatment, allowing the identification of a group of patients less likely to benefit from tamoxifen and thus in need of an alternative or additional targeted treatment.

CDK4 inhibition and doxorubicin mediate breast cancer cell apoptosis through Smad3 and survivin

Cyclin D1/CDK4 activity is upregulated in up to 50% of breast cancers and CDK4-mediated phosphorylation negatively regulates the TGFβ superfamily member Smad3. We sought to determine if CDK4 inhibition and doxorubicin chemotherapy could impact Smad3-mediated cell/colony growth and apoptosis in breast cancer cells. Parental and cyclin D1-overexpressing MCF7 cells were treated with CDK4 inhibitor, doxorubicin, or combination therapy and cell proliferation, apoptosis, colony formation, and expression of apoptotic proteins were evaluated using an MTS assay, TUNEL staining, 3D Matrigel assay, and apoptosis array/immunoblotting. Study cells were also transduced with WT Smad3 or a Smad3 construct resistant to CDK4 phosphorylation (5M) and colony formation and expression of apoptotic proteins were assessed. Treatment with CDK4 inhibitor/doxorubicin combination therapy, or transduction with 5M Smad3, resulted in a similar decrease in colony formation. Treating cyclin D overexpressing breast cancer cells with combination therapy also resulted in the greatest increase in apoptosis, resulted in decreased expression of anti-apoptotic proteins survivin and XIAP, and impacted subcellular localization of pro-apoptotic Smac/DIABLO. Additionally, transduction of 5M Smad3 and doxorubicin treatment resulted in the greatest change in apoptotic protein expression. Collectively, this work showed the impact of CDK4 inhibitor-mediated, Smad3-regulated tumor suppression, which was augmented in doxorubicin-treated cyclin D-overexpressing study cells.

miR-379 regulates cyclin B1 expression and is decreased in breast cancer

MicroRNAs are small non-coding RNA molecules that control gene expression post-transcriptionally, and are known to be altered in many diseases including breast cancer. The aim of this study was to determine the relevance of miR-379 in breast cancer. miR-379 expression was quantified in clinical samples including tissues from breast cancer patients (n=103), healthy controls (n=30) and patients with benign breast disease (n=35). The level of miR-379 and its putative target Cyclin B1 were investigated on all breast tissue specimens by RQ-PCR. Potential relationships with gene expression and patient clinicopathological details were also determined. The effect of miR-379 on Cyclin B1 protein expression and function was investigated using western blot, immunohistochemistry and proliferation assays respectively. Finally, the levels of circulating miR-379 were determined in whole blood from patients with breast cancer (n=40) and healthy controls (n=34). The level of miR-379 expression was significantly decreased in breast cancer (Mean(SEM) 1.9 (0.09) Log₁₀ Relative Quantity (RQ)) compared to normal breast tissues (2.6 (0.16) Log₁₀ RQ, p<0.01). miR-379 was also found to decrease significantly with increasing tumour stage. A significant negative correlation was determined between miR-379 and Cyclin B1 (r=-0.31, p<0.001). Functional assays revealed reduced proliferation (p<0.05) and decreased Cyclin B1 protein levels following transfection of breast cancer cells with miR-379. Circulating miR-379 was not significantly dysregulated in patients with breast cancer compared to healthy controls (p=0.42). This data presents miR-379 as a novel regulator of Cyclin B1 expression, with significant loss of the miRNA observed in breast tumours.

RNA sequencing of MCF-7 breast cancer cells identifies novel estrogen-responsive genes with functional estrogen receptor-binding sites in the vicinity of their transcription start sites

Estrogen receptor α (ERα) is a key transcription factor in breast cancer, which plays an essential role in the pathophysiology of the disease by regulating the expression of various target genes. In the present study, we performed deep RNA sequencing (RNA-seq) as an unbiased high-throughput technique for comprehensive transcriptome analysis in ERα-positive human breast cancer MCF-7 cells, to facilitate the elucidation of ERα regulatory gene networks. From the 17,336 mapped RefSeq genes from the sequenced fragments of the cell samples treated with estrogen time dependently, substantial numbers of sequence reads were observed in 3,386 genes (>100 tags per million reads per sample at any of the six time points studied). ERα occupancy within and in the proximal regions of the genes (<10-kb upstream and downstream regions) was significantly enriched in the subgroup of the 3,386 genes compared to the whole 17,336 RefSeq genes. Of the 3,386 genes, we focused on 29 genes, which included ERα occupancy adjacent to their transcription start sites and whose expression was estrogen dependently altered by >3-fold. Knockdown studies using siRNAs specific to the 29 genes validated that prototypic ERα targets V-myc myelocytomatosis viral oncogene homolog and cyclin D1 promote both proliferation and migration of MCF-7 cells and further identified novel candidate ERα targets EIF3A and tumor protein D52-like 1, which will also facilitate the proliferation or migration of MCF-7 cells. Taken together, the present findings provide a valuable dataset that will elucidate ERα regulatory mechanisms in breast cancer biology, based on the integrative analysis of RNA-seq combined with the genome-wide information for ERα occupancy.

Low cyclin F expression in hepatocellular carcinoma associates with poor differentiation and unfavorable prognosis

Cyclin F, capable of forming Skp1-Cul1-F-box protein ubiquitin ligase complex, is implicated in controlling centrosome duplication and preventing genome instability. Cyclin F oscillates during cell cycle with a similar pattern to cyclin A. However, its expression and significance in cancer remain obscure. In this study, we showed that cyclin F was noticeably decreased in 16 pairs of tissue samples of hepatocellular carcinoma (HCC) compared to paracarcinoma tissues, at both mRNA and protein levels. Immunohistochemical staining data revealed that in 71.8% (176/245) of HCC cases, cyclin F expression in tumor tissue was much lower than that in nontumorous tissue. Low cyclin F expression, defined by receiver operating characteristic curve analysis, was present in 69.0% of HCC patients. Low expression of cyclin F was significantly correlated with tumor size, clinical stage, serum alpha-fetoprotein level and tumor multiplicity. Further study showed that cyclin F expression was reversely associated with tumor differentiation in HCC. Kaplan-Meier analysis indicated that low cyclin F expression was related to poor overall survival and recurrence-free survival. The prognostic impact of cyclin F was further confirmed by stratified survival analysis. Importantly, multivariate analysis revealed that low cyclin F expression was an independent poor prognostic marker for overall survival. We conclude that cyclin F is downregulated in HCC and is a promising prognostic marker for patients suffering from this deadly disease.

Fruit and vegetable intake and risk of breast cancer by hormone receptor status

BACKGROUND

Estrogen receptor-negative (ER(-)) breast cancer has few known or modifiable risk factors. Because ER(-) tumors account for only 15% to 20% of breast cancers, large pooled analyses are necessary to evaluate precisely the suspected inverse association between fruit and vegetable intake and risk of ER(-) breast cancer.

METHODS

Among 993 466 women followed for 11 to 20 years in 20 cohort studies, we documented 19 869 estrogen receptor positive (ER(+)) and 4821 ER(-) breast cancers. We calculated study-specific multivariable relative risks (RRs) and 95% confidence intervals (CIs) using Cox proportional hazards regression analyses and then combined them using a random-effects model. All statistical tests were two-sided.

RESULTS

Total fruit and vegetable intake was statistically significantly inversely associated with risk of ER(-) breast cancer but not with risk of breast cancer overall or of ER(+) tumors. The inverse association for ER(-) tumors was observed primarily for vegetable consumption. The pooled relative risks comparing the highest vs lowest quintile of total vegetable consumption were 0.82 (95% CI = 0.74 to 0.90) for ER(-) breast cancer and 1.04 (95% CI = 0.97 to 1.11) for ER(+) breast cancer (P (common-effects) by ER status < .001). Total fruit consumption was non-statistically significantly associated with risk of ER(-) breast cancer (pooled multivariable RR comparing the highest vs lowest quintile = 0.94, 95% CI = 0.85 to 1.04).

CONCLUSIONS

We observed no association between total fruit and vegetable intake and risk of overall breast cancer. However, vegetable consumption was inversely associated with risk of ER(-) breast cancer in our large pooled analyses.

High proliferation is associated with inferior outcome in male breast cancer patients

Assessment of proliferation is important in female breast cancer and individual treatment decisions are based upon its results, especially in the luminal subgroups. Gene expression analyses fail to group male breast cancer into the intrinsic subgroups previously established in female breast cancer. Even though proliferation has been shown to divide male breast cancer into molecular subgroups with different prognoses, the clinical importance of proliferation markers has not yet been elucidated. Previous studies in male breast cancer have demonstrated contradictory results regarding the prognostic impact of histological grade and Ki-67, parameters strongly associated with proliferation. The aim of the present project was to study proliferation in male breast cancer by assessing other proliferation-related markers viz. cyclins A, B, D1 and mitotic count. A total of 197 male breast cancer cases with accessible paraffin-embedded material and outcome data were investigated. Immunohistochemical stainings were performed on tissue microarrays. Kaplan-Meier estimates and the Cox proportional regression models were used for survival analyses with breast cancer death as the event. The subset of patients with high expression of cyclin A (hazard ratio (HR) 3.7; P=0.001) and B (HR 2.7; P=0.02) demonstrated a poorer survival. Furthermore, high mitotic count was associated with an increased risk of breast cancer death (HR 2.5; P=0.01). In contrast, cyclin D1 overexpression was predictive of better breast cancer survival (HR 0.3; P=0.001). In conclusion, high levels of cyclin A and B expression and an elevated mitotic count result in a two to threefold higher risk for breast cancer death, whereas cyclin D1 overexpression halves the risk. The clinical utility of these proliferation markers needs further elucidation.

Increased HoxB4 Inhibits Apoptotic Cell Death in Pro-B Cells

HoxB4, a homeodomain-containing transcription factor, is involved in the expansion of hematopoietic stem cells and progenitor cells in vivo and in vitro, and plays a key role in regulating the balance between hematopoietic stem cell renewal and cell differentiation. However, the biological activity of HoxB4 in other cells has not been reported. In this study, we investigated the effect of overexpressed HoxB4 on cell survival under various conditions that induce death, using the Ba/F3 cell line. Analysis of phenotypical characteristics showed that HoxB4 overexpression in Ba/F3 cells reduced cell size, death, and proliferation rate. Moreover, the progression from early to late apoptotic stages was inhibited in Ba/F3 cells subjected to HoxB4 overexpression under removal of interleukin-3-mediated signal, leading to the induction of cell cycle arrest at the G2/M phase and attenuated cell death by Fas protein stimulation in vitro. Furthermore, apoptotic cell death induced by doxorubicin-treated G2/M phase cell-cycle arrest also decreased with HoxB4 overexpression in Ba/F3 cells. From these data, we suggest that HoxB4 may play an important role in the regulation of pro-B cell survival under various apoptotic death environments.

The CDK4/6 inhibitor PD0332991 reverses epithelial dysplasia associated with abnormal activation of the cyclin-CDK-Rb pathway

Loss of normal growth control is a hallmark of cancer progression. Therefore, understanding the early mechanisms of normal growth regulation and the changes that occur during preneoplasia may provide insights of both diagnostic and therapeutic importance. Models of dysplasia that help elucidate the mechanisms responsible for disease progression are useful in highlighting potential targets for prevention. An important strategy in cancer prevention treatment programs is to reduce hyperplasia and dysplasia. This study identified abnormal upregulation of cell cycle-related proteins cyclin D1, cyclin-dependent kinase (CDK)4, CDK6, and phosphorylated retinoblastoma protein (pRb) as mechanisms responsible for maintenance of hyperplasia and dysplasia following downregulation of the initiating viral oncoprotein Simian virus 40 (SV40) T antigen. Significantly, p53 was not required for successful reversal of hyperplasia and dysplasia. Ligand-induced activation of retinoid X receptor and PPARγ agonists attenuated cyclin D1 and CDK6 but not CDK4 or phosphorylated pRb upregulation with limited reversal of hyperplasia and dysplasia. PD0332991, an orally available CDK4/6 inhibitor, was able to prevent upregulation of cyclin D1 and CDK6 as well as CDK4 and phosphorylated pRb and this correlated with a more profound reversal of hyperplasia and dysplasia. In summary, the study distinguished CDK4 and phosphorylated pRb as targets for chemoprevention regimens targeting reversal of hyperplasia and dysplasia.

Association of Over-Expressed Estrogen Receptor Alpha with Development of Tamoxifen Resistant Hyperplasia and Adenocarcinomas in Genetically Engineered Mice

BACKGROUND

Estrogen receptor alpha (ERα) and cyclin D1 are frequently co-expressed in human breast cancer. Some, but not all, studies link tamoxifen resistance to co-expression of cyclin D1 and ERα. In mice over-expression of either cyclin D1 or ERα in mammary epithelial cells is sufficient to induce mammary hyperplasia. Cyclin D1 over-expression in mice leads to mammary adenocarcinoma associated with activated estrogen signaling pathways. ERα over-expression in mice leads to mammary hyperplasia and cancer. Significantly, disease development in these mice is abrogated by loss of cyclin D1.

METHODS

Genetically engineered mouse models were used to determine whether or not ERα over-expression demonstrated cooperativity with cyclin D1 over-expression in cancer development, reaction to the chemical carcinogen DMBA, or tamoxifen response.

RESULTS

Adding ERα over-expression to cyclin D1 over-expression increased the prevalence of hyperplasia but not cancer. Single dose DMBA exposure did not increase cancer prevalence in any of the genotypes although cyclin D1 over-expressing mice demonstrated a significant increase in hyperplasia. Tamoxifen treatment was initiated at both young and older ages to test for genotype-specific differences in response. Although normal ductal structures regressed in all genotypes at both younger and older ages, tamoxifen did not significantly reduce the prevalence of either hyperplasia or cancer in any of the genotypes. All of the cancers that developed were hormone receptor positive, including those that developed on tamoxifen, and all showed expression of nuclear-localized cyclin D1. In summary, development of tamoxifen resistant hyperplasia and cancer was associated with expression of ERα and cyclin D1.

CONCLUSION

These preclinical models will be useful to test strategies for overcoming tamoxifen resistance, perhaps by simultaneously targeting cell cycle regulatory pathways associated with cyclin D1.

Targeting the Akt/mTOR pathway in Brca1-deficient cancers

The breast cancer susceptibility gene 1 (Brca1) has a key role in both hereditary and sporadic mammary tumorigenesis. However, the reasons why Brca1-deficiency leads to the development of cancer are not clearly understood. Activation of Akt kinase is one of the most common molecular alterations associated with human malignancy. Increased Akt kinase activity has been reported in most breast cancers. We previously found that downregulation of Brca1 expression or mutations of the Brca1 gene activate the Akt oncogenic pathway. To further investigate the role of Brca1/Akt in tumorigenesis, we analyzed Brca1/Akt expression in human breast cancer samples and found that reduced expression of Brca1 was highly correlated with increased phosphorylation of Akt. Consistent with the clinical data, knockdown of Akt1 by short-hairpin RNA inhibited cellular proliferation of Brca1 mutant cells. Importantly, depletion of Akt1 significantly reduced tumor formation induced by Brca1-deficiency in mice. The third generation inhibitor of mammalian target of rapamycin (mTOR), Palomid 529, significantly suppressed Brca1-deficient tumor growth in mice through inhibition of both Akt and mTOR signaling. Our results indicate that activation of Akt is involved in Brca1-deficiency mediated tumorigenesis and that the mTOR pathway can be used as a novel target for treatment of Brca1-deficient cancers.

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.

Glycodelin expression associates with differential tumour phenotype and outcome in sporadic and familial non-BRCA1/2 breast cancer patients

Glycodelin (encoded by PAEP gene) is a secreted lipocalin protein mainly expressed in reproductive tissues, but also in several tumour types. In the breast, glycodelin is expressed both in normal epithelial and cancerous tissue. To investigate the association of glycodelin with clinicopathological features of breast cancer and outcome of patients we evaluated the protein expression of glycodelin in a large series of breast tumours. Immunohistochemical analysis of tissue microarrays was used to study glycodelin expression on 399 sporadic and 436 familial non-BRCA1/2 tumours with strong family history. Gene expression analysis was used to define genes co-expressed with PAEP in sporadic and familial non-BRCA1/2 breast tumours. In the sporadic series, the glycodelin expression associated with low proliferation rate (P < 0.001), with a tendency towards well-differentiated tumours (grades 1 and 2, P = 0.012) and high cyclin D1 (P = 0.034) expression. However, in familial non-BRCA1/2 cases with strong family history glycodelin expression associated with a less favourable phenotype, i.e. positive lymph node status (P = 0.003) and HER2-positive tumours (P = 0.009). Moreover, the patients with glycodelin-positive tumours had an increased risk for distant metastases (P = 0.001) and in multivariate analysis glycodelin expression was an independent predictor of metastasis (hazard ratio (HR) = 2.22, 95% confidence interval (95% CI) = 1.22-4.03, P = 0.009) in familial non-BRCA1/2 breast cancer. Gene expression analysis further revealed different gene expression profiles correlating with the PAEP expression in the sporadic and familial non-BRCA1/2 breast cancers. Our findings suggest differential progression pathways in the sporadic and familial non-BRCA1/2 breast tumours expressing glycodelin.

Premalignant breast neoplasia: a paradigm of interlesional and intralesional molecular heterogeneity and its biological and clinical ramifications

As is well established in invasive breast disease, it is becoming increasingly clear that molecular heterogeneity, both between and within lesions, is a prevalent, distinct phenotype of premalignant lesions of the breast. Key pathways of tumorigenesis modulate critical features of premalignant lesions such as proliferation, differentiation, stress response, and even the generation of diversity. Current studies show that evaluation of these lesions may provide clinically useful information on future tumor formation as well as biological insights into the origin and functional significance of this distinct phenotype.

Cyclin D1 is a direct target of JAG1-mediated Notch signaling in breast cancer

The Notch ligand, JAG1 is associated with breast cancer recurrence. Herein, we report on a genomics approach to elucidate mechanisms downstream of JAG1 that promote breast cancer growth. In a survey of 46 breast cancer cell lines, we found that triple negative (TN; basal and mesenchymal ER-, PR-, and Her2-negative) lines express JAG1 at significantly higher levels than do HER2(+) or luminal (ER(+)) Her2(-) cell lines. In contrast to the luminal lines tested (T47D and MCF7), TN breast cancer cell lines (HCC1143 and MDA MB231) display high-level JAG1 expression and growth inhibition with RNA interference-induced JAG1 down-regulation. We used microarray profiling of TN tumor cells transfected with JAG1 siRNA to identify JAG1-regulated genes (P <or= 0.005; fold change >or=1.5). Among JAG1-regulated genes identified, cyclin D1 was found to be a direct target of NOTCH1 and NOTCH3. We show that JAG1 down-regulation reduces direct binding of Notch to the cyclin D1 promoter, reduced cyclin D1 expression and inhibition of cell cycle progression through the cyclin D1-dependant G1/S checkpoint. Furthermore, we show that cyclin D1 and JAG1 expression correlate in TN breast cancer expression datasets. These data suggest a model whereby JAG1 promotes cyclin D1-mediated proliferation of TN breast cancers.

Analysis of cyclins A, B1, D1 and E in breast cancer in relation to tumour grade and other prognostic factors

Background

The cell cycle is promoted by activation of cyclin dependent kinases (Cdks), which are regulated positively by cyclins and negatively by Cdk inhibitors. Proliferation of carcinoma is associated with altered regulation of the cell cycle. Little is known on the combined alterations of cyclins A, B1, D1 and E in breast cancer in relation to the tumour grade and other prognostic factors.

Findings

Immunohistochemical analysis of cyclins A, B1, D1 and E, estrogen receptor, progesterone receptor, Ki-67, Her-2/neu and CK5/6 was performed on 53 breast carcinomas. mRNA levels of the cyclins were analysed of 12 samples by RT-PCR. The expression of cyclins A, B1 and E correlated with each other, while cyclin D1 correlated with none of these cyclins. Cyclins A, B1 and E showed association with tumour grade, Her-2/neu and Ki-67. Cyclin E had a negative correlation with hormone receptors and a positive correlation with triple negative carcinomas. Cyclin D1 had a positive correlation with ER, PR and non-basal breast carcinomas.

Conclusion

Cyclin A, B1 and E overexpression correlates to grade, Ki-67 and Her2/neu expression. Overexpression of cyclin D1 has a positive correlation with receptor status and non-basal carcinomas suggesting that cyclin D1 expression might be a marker of good prognosis. Combined analysis of cyclins indicates that cyclin A, B and E expression is similarly regulated, while other factors regulate cyclin D1 expression. The results suggest that the combined immunoreactivity of cyclins A, B1, D and E might be a useful prognostic factor in breast cancer.

The breast cancer susceptibility mutation PALB2 1592delT is associated with an aggressive tumor phenotype

PURPOSE

To determine the effect of the breast cancer susceptibility mutation PALB2 1592delT on tumor phenotype and patient survival.

EXPERIMENTAL DESIGN

We defined the PALB2 mutation status in 947 familial and 1,274 sporadic breast cancer patients and 1,079 population controls, and compared tumor characteristics and survival in mutation carriers relative to other familial and sporadic cases and to 79 BRCA1 and 104 BRCA2 mutation carrier cases.

RESULTS

The PALB2 1592delT mutation was found in 19 familial [2.0%; odds ratio, 11.03; 95% confidence interval (95% CI), 2.65-97.78; P < 0.0001] and eight sporadic patients (0.6%; odds ratio, 3.40; 95% CI, 0.68-32.95; P = 0.1207) compared with two (0.2%) control individuals. Tumors of the PALB2 mutation carriers presented triple negative (estrogen receptor negative/progesterone receptor negative/HER negative) phenotype more often (54.5%; P < 0.0001) than those of other familial (12.2%) or sporadic (9.4%) breast cancer patients. They were also more often of higher grade (P = 0.0027 and P = 0.0017, respectively) and had higher expression of Ki67 (P = 0.0004 and P = 0.0490, respectively). Carrying a PALB2 mutation was also associated with reduced survival, especially in familial cases (hazard ratio, 2.30; 95% CI, 1.01-5.24; P = 0.0466) and among familial patients with HER2-negative tumors (hazard ratio, 4.57; 95% CI, 1.96-10.64; P = 0.0004). Carrying a BRCA2 mutation was also found to be an independent predictor of poor survival at 10-year follow-up (P = 0.04).

CONCLUSIONS

The PALB2 1592delT mutation has a strong effect on familial breast cancer risk. The tumors rising in patients carrying this mutation manifest a phenotype associated with aggressive disease. Our results also suggest a significant impact of carrying a BRCA2 mutation on long-term breast cancer survival.