Cyclin E amplification, over-expression, and relapse-free survival in HER-2-positive primary breast cancer

Phosphorylated Adapter RNA Export Protein Is Methylated at Lys 381 by an Methyltransferase-like 21C (METTL21C)

Methyltransferase-like 21C (METTL21C) is a member of the non-histone methyltransferase superfamily, which mainly mediates the methylation of lysine (Lys) residues. The main types of modification are Lys dimethylation and trimethylation. However, at present, most of the studies on METTL21C are focused on humans and mice, and there are few reports on poultry. Therefore, chicken embryo fibroblasts (DF-1) were selected as the object of study. To explore the function of chicken METTL21C (chMETTL21C) in the proliferation of DF-1 cells, flow cytometry and qPCR were used to detect the function of chicken METTL21C in the proliferation of DF-1 cells. The results showed that overexpression of METTL21C blocked the cell cycle in the G1max S phase, thus inhibiting cell proliferation. In addition, based on proteomic analysis, stable overexpression of METTL21C may inhibit the proliferation of DF-1 cells by mediating lysine trimethylation of proliferation-related proteins phosphorylated adapter RNA export protein (PHAX), nucleoside diphosphate kinases (NDPKs), eukaryotic transcription extension factor (eukaryotic translation elongation factor 1A,e EF1A), and inversin (Invs). Through immunoprecipitation (co-IP) and liquid chromatography-mass spectrometry (LC-MS/MS) analysis, METTL21C-mediated PHAX Lys-381 methylation was confirmed to be involved in the regulation of DF-1 cell proliferation. The results of this study provide a reference for analyzing the methylation function of METTL21C and the mechanism of regulating the growth and development of chicken cells.

Empower the Potential of Trastuzumab Deruxtecan with Novel Combinations

Trastuzumab deruxtecan (T-DXd) is reshaping the therapeutic landscape of HER2-positive tumors. A recent article reports on the preclinical activity of the combination of T-DXd plus adavosertib, WEE1 kinase inhibitor, which promises to expand the use of this antibody-drug conjugate in HER2-positive tumors with CCNE1 coamplification. See related article by DiPeri et al., p. 4385.

Adavosertib Enhances Antitumor Activity of Trastuzumab Deruxtecan in HER2-Expressing Cancers

PURPOSE

Cyclin E (CCNE1) has been proposed as a biomarker of sensitivity to adavosertib, a Wee1 kinase inhibitor, and a mechanism of resistance to HER2-targeted therapy.

EXPERIMENTAL DESIGN

Copy number and genomic sequencing data from The Cancer Genome Atlas and MD Anderson Cancer Center databases were analyzed to assess ERBB2 and CCNE1 expression. Molecular characteristics of tumors and patient-derived xenografts (PDX) were assessed by next-generation sequencing, whole-exome sequencing, fluorescent in situ hybridization, and IHC. In vitro, CCNE1 was overexpressed or knocked down in HER2+ cell lines to evaluate drug combination efficacy. In vivo, NSG mice bearing PDXs were subjected to combinatorial therapy with various treatment regimens, followed by tumor growth assessment. Pharmacodynamic markers in PDXs were characterized by IHC and reverse-phase protein array.

RESULTS

Among several ERBB2-amplified cancers, CCNE1 co-amplification was identified (gastric 37%, endometroid 43%, and ovarian serous adenocarcinoma 41%). We hypothesized that adavosertib may enhance activity of HER2 antibody-drug conjugate trastuzumab deruxtecan (T-DXd). In vitro, sensitivity to T-DXd was decreased by cyclin E overexpression and increased by knockdown, and adavosertib was synergistic with topoisomerase I inhibitor DXd. In vivo, the T-DXd + adavosertib combination significantly increased γH2AX and antitumor activity in HER2 low, cyclin E amplified gastroesophageal cancer PDX models and prolonged event-free survival (EFS) in a HER2-overexpressing gastroesophageal cancer model. T-DXd + adavosertib treatment also increased EFS in other HER2-expressing tumor types, including a T-DXd-treated colon cancer model.

CONCLUSIONS

We provide rationale for combining T-DXd with adavosertib in HER2-expressing cancers, especially with co-occuring CCNE1 amplifications. See related commentary by Rolfo et al., p. 4317.

Mechanistic and Clinical Evidence Supports a Key Role for Cell Division Cycle Associated 5 (CDCA5) as an Independent Predictor of Outcome in Invasive Breast Cancer

BACKGROUND

Cell Division Cycle Associated 5 (CDCA5) plays a role in the phosphoinositide 3-kinase (PI3K)/AKT/mTOR signalling pathway involving cell division, cancer cell migration and apoptosis. This study aims to assess the prognostic and biological value of CDCA5 in breast cancer (BC).

METHODS

The biological and prognostic value of CDCA5 were evaluated at mRNA (n = 5109) and protein levels (n = 614) utilizing multiple well-characterized early stage BC cohorts. The effects of CDCA5 knockdown (KD) on multiple oncogenic assays were assessed in vitro using a panel of BC cell lines.

RESULTS

this study examined cohorts showed that high CDCA5 expression was correlated with features characteristic of aggressive behavior and poor prognosis, including the presence of high grade, large tumor size, lymphovascular invasion (LVI), hormone receptor negativity and HER2 positivity. High CDCA5 expression, at both mRNA and protein levels, was associated with shorter BC-specific survival independent of other variables (p = 0.034, Hazard ratio (HR) = 1.6, 95% CI; 1.1-2.3). In line with the clinical data, in vitro models indicated that CDCA5 depletion results in a marked decrease in BC cell invasion and migration abilities and a significant accumulation of the BC cells in the G2/M-phase.

CONCLUSIONS

These results provide evidence that CDCA5 plays an important role in BC development and metastasis and could be used as a potential biomarker to predict disease progression in BC.

Identification of tumor antigens and immunogenic cell death-related subtypes for the improvement of immunotherapy of breast cancer

The current immunotherapy strategy for breast cancer is limited. Tumor neoantigens have been proven to be a promising biomarker and potential target of immunotherapy in a variety of tumors. However, their effectiveness for breast cancer remains unclear. Immunogenic cell death (ICD) is a regulated form of cell death that can reshape the tumor immune microenvironment and activate adaptive immune responses. To this end, we screened potential antigens that could be used both for the development of immunotherapy and differentiating the patient-specific immune responses based on ICD-related risk signatures, in order to formulate an accurate scheme for breast cancer immunotherapy. We retrieved the gene expression profiles of the breast invasive cancer cohort and their corresponding clinical control data from The Cancer Genome Atlas. The Gene Expression Profiling Interactive Analysis (GEPIA) database was used to evaluate tumor antigen expression, the cBioPortal program was used to identify genetic variations, and the TIMER website was used to estimate the immune infiltration signatures. The risk score predictive model based on the ICD-related genes was constructed using the least absolute shrinkage and selection operator (LASSO) Cox regression algorithm, and the cohort was divided into low- and high-risk score groups. Two tumor antigens, namely, CCNE1 and PLK1, were associated with poor prognosis and infiltration of antigen-presenting cells. Furthermore, the ICD-related risk signature could significantly predict survival outcomes. The risk groups based on the ICD-related signature predictive model showed diverse immune infiltration and molecular and clinical features. The high-risk group was associated with low immune cell infiltration, immune score, expression of immune checkpoints, and human leukocyte antigen genes but high levels of CCNE1 and PLK1 and poor survival outcome. In conclusion, CCNE1 and PLK1 were identified as potential antigens in breast cancer. The ICD-related prognostic model distinguished immune response heterogeneity and predicted prognosis. Patients with high ICD-related risk scores were suitable to receive combination treatments based on CCNE1 or PLK1 and immune checkpoint inhibitors. In the future, these results will help us develop more accurate treatment schemes for patients with breast cancer.

High cyclin E1 protein, but not gene amplification, is prognostic for basal-like breast cancer

Basal-like breast cancer (BLBC) has a greater overlap in molecular features with high-grade serous ovarian cancer (HGSOC) than with other breast cancer subtypes. Similarities include BRCA1 mutation, high frequency of TP53 mutation, and amplification of CCNE1 (encoding the cyclin E1 protein) in 6-34% of cases, and these features can be used to group patients for targeted therapies in clinical trials. In HGSOC, we previously reported two subsets with high levels of cyclin E1: those in which CCNE1 is amplified, have intact homologous recombination (HR), and very poor prognosis; and a CCNE1 non-amplified subset, with more prevalent HR defects. Here, we investigate whether similar subsets are identifiable in BLBC that may allow alignment of patient grouping in clinical trials of agents targeting cyclin E1 overexpression. We examined cyclin E1 protein and CCNE1 amplification in a cohort of 76 BLBCs and validated the findings in additional breast cancer datasets. Compared to HGSOC, CCNE1 amplified BLBC had a lower level of amplification (3.5 versus 5.2 copies) and lower relative cyclin E1 protein, a lack of correlation of amplification with expression, and no association with polyploidy. BLBC with elevated cyclin E1 protein also had prevalent HR defects, and high-level expression of the cyclin E1 deubiquitinase ubiquitin-specific protease 28 (USP28). Using a meta-analysis across multiple studies, we determined that cyclin E1 protein overexpression but not amplification is prognostic in BLBC, while both cyclin E1 overexpression and amplification are prognostic in HGSOC. Overall CCNE1 gene amplification is not equivalent between BLBC and HGSOC. However, high cyclin E1 protein expression can co-occur with HR defects in both BLBC and HGSOC, and is associated with poor prognosis in BLBC.

Influence of gene expression on survival of clear cell renal cell carcinoma

Approximately 10%‐20% of patients with clinically localized clear cell renal cell carcinoma (ccRCC) at time of surgery will subsequently experience metastatic progression. Although considerable progression was seen in the systemic treatment of metastatic ccRCC in last 20 years, once ccRCC spreads beyond the confines of the kidney, 5‐year survival is less than 10%. Therefore, significant clinical advances are urgently needed to improve overall survival and patient care to manage the growing number of patients with localized ccRCC. We comprehensively evaluated expression of 388 candidate genes related with survival of ccRCC by using TCGA RNAseq (n = 515), Total Cancer Care (TCC) expression array data (n = 298), and a well characterized Moffitt RCC cohort (n = 248). We initially evaluated all 388 genes for association with overall survival using TCGA and TCC data. Eighty‐one genes were selected for further analysis and tested on Moffitt RCC cohort using NanoString expression analysis. Expression of nine genes (AURKA, AURKB, BIRC5, CCNE1, MK167, MMP9, PLOD2, SAA1, and TOP2A) was validated as being associated with poor survival. Survival prognostic models showed that expression of the nine genes and clinical factors predicted the survival in ccRCC patients with AUC value: 0.776, 0.821 and 0.873 for TCGA, TCC and Moffitt data set, respectively. Some of these genes have not been previously implicated in ccRCC survival and thus potentially offer insight into novel therapeutic targets. Future studies are warranted to validate these identified genes, determine their biological mechanisms and evaluate their therapeutic potential in preclinical studies.

The root cause of drug resistance in HER2-positive breast cancer and the therapeutic approaches to overcoming the resistance

HER2 is a well-known oncogenic receptor tyrosine kinase. HER2 gene amplification occurs in about 20% of breast cancer (BC), which leads to overexpression of HER2 protein, known as HER2-positive BC. Inhibitors of HER2 have significantly improved the prognosis of patients with this subset of BC. Since 1998, seven HER2 inhibitors have been developed to treat this disease. However, drug resistance is common and remains a major unresolved clinical problem. Patients typically show disease progression after some time on treatment. This review discusses the complexity and diversified nature of HER2 signaling, the mechanisms of actions and therapeutic activities of all HER2 inhibitors, the roles of HER2 and other signaling proteins in HER2-positive BC resistant to the inhibitors, the non-cell-autonomous mechanisms of drug resistance, and the heterogeneity of tumor HER2 expression. The review presents the concept that drug resistance in HER2-positive BC results primarily from the inability of HER2 inhibitors to deplete HER2. Emerging therapeutics that are promising for overcoming drug resistance are also discussed.

gga-microRNA-375 negatively regulates the cell cycle and proliferation by targeting Yes-associated protein 1 in DF-1 cells

MicroRNAs (miRNAs/miRs) serve a key role in regulating the cell cycle and inducing tumorigenesis. Subgroup J of the avian leukosis virus (ALV-J) belongs to the family Retroviridae, subfamily Orthoretrovirinae and genus Alpharetrovirus that causes tumors in susceptible chickens. gga-miR-375 is downregulated and Yes-associated protein 1 (YAP1) is upregulated in ALV-J-induced tumors in the livers of chickens, and it has been further identified that YAP1 is the direct target gene of gga-miR-375. In the present study, it was found that ALV-J infection promoted the cell cycle and proliferation in DF-1 cells. As the cell cycle and cell proliferation are closely associated with tumorigenesis, further experiments were performed to determine whether gga-miR-375 and YAP1 were involved in these cellular processes. It was demonstrated that gga-miR-375 significantly inhibited the cell cycle by inhibiting G₁ to S/G₂ stage transition and decreasing cell proliferation, while YAP1 significantly promoted the cell cycle and proliferation. Furthermore, these cellular processes in DF-1 cells were affected by gga-miR-375 through the targeting of YAP1. Collectively, the present results suggested that gga-miR-375, downregulated by ALV-J infection, negatively regulated the cell cycle and proliferation via the targeting of YAP1.

Efficacy analysis of trastuzumab, carboplatin and docetaxel in HER-2-positive breast cancer patients

Efficacy of trastuzumab, carboplatin and docetaxel in human epidermal growth factor receptor-2 (HER-2)-positive breast cancer patients was investigated. A total of 180 HER-2-positive breast cancer patients admitted to The First People's Hospital of Yunnan Province were selected, of which 80 patients were treated with carboplatin and docetaxel and served as the control group (CG), and 100 patients were treated with trastuzumab, carboplatin and docetaxel and served as the research group (RG). Clinical efficacy, pathological efficacy, adverse reactions, inflammatory factors interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), cellular immune indexes of T-lymphocyte subsets (CD4⁺, CD8⁺, CD4⁺/CD8⁺), and the oxidative stress indexes superoxide dismutase (SOD) and myeloperoxidase (MPO) were observed before and after treatment and were compared between both groups. Patients were followed up for 5 years, and the 5-year disease-free survival (DFS), as well as the overall survival (OS) were compared. Clinical efficacy and pathological efficacy in the RG were significantly higher than those in the CG, and the incidence rate of adverse reactions had no significant difference between the two groups. There was no significant difference in inflammatory factors, cellular immune indexes and oxidative stress indexes between the two groups before treatment. After treatment, the levels of IL-6, TNF-α, CD8⁺ and MPO in both groups were significantly reduced and were significantly lower in RG than those in CG. However, the levels of CD4⁺, CD4⁺/CD8⁺ and SOD in both groups were significantly increased after treatment and were significantly higher in RG than those in CG. The 5-year DFS and OS of the RG were significantly higher than those of the CG. In conclusion, trastuzumab, carboplatin and docetaxel present high efficacy, safety, and 5-year DFS and OS in HER-2-positive breast cancer patients, and have good recovery effect on inflammation, immune response and oxidative stress.

Aberrant Cyclin E and Hepatocyte Growth Factor Expression, Microvascular Density, and Micro-Lymphatic Vessel Density in Esophageal Squamous Cell Carcinoma

Cyclin E and hepatocyte growth factor (HGF) have been observed as a multifaceted factor in many cancers, and the assessment of microvascular density (MVD) and micro-lymphatic vessel density (MLVD) has been used to quantify tumor angiogenesis and lymphangiogenesis. The aim of this study was to explore the association between expression of cyclin E, HGF, MVD, and MLVD, and clinicopathologic parameters in esophageal squamous cell carcinoma (ESCC). The expression of cyclin E, HGF, MVD, and MLVD were detected using immunohistochemically anticyclin E, HGF, CD34, and lymphatic vessel endothelial hyaluronan receptor 1 in 168 surgically resected ESCC cases and 30 normal esophageal mucosal samples. The expression levels of cyclin E, HGF, MVD, and MLVD were higher compared to controls. High cyclin E and HGF expression was found more frequently in the tumors larger than 5 cm (P < .001), with poorer differentiation (P = .034) and higher tumor node metastasis (TNM) staging (P = .009) compared to their counterparts. Both MVD and MLVD values were found to be higher in the tumors larger than 5 cm (P < .001), with poorer differentiation (P < .001) and higher TNM staging (P < .001) compared to their counterparts. Furthermore, the expression of MVD and MLVD in both the high cyclin E and high HGF expression groups was significantly higher compared to the low cyclin E and HGF expression groups (P < .001). This study demonstrated that high cyclin E and HGF expression is closely correlated with tumor size, tumor differentiation degree, and TNM stage in patients with ESCC. These findings proposed that cyclin E and HGF could serve as novel molecular markers for preoperational evaluation of ESCC.

Sorting Nexin 5 Controls Head and Neck Squamous Cell Carcinoma Progression by Modulating FBW7

Head and neck squamous cell carcinoma (HNSCC) is the sixth most prevalent cancer worldwide. Long-term survival rates in patients with HNSCC have not increased significantly in the past 30 years. Therefore, looking for novel molecular targets that control HNSCC progression is urgently required to improve the treatment of HNSCC. Here, we identified Sorting Nexin 5 (SNX5) as a new regulator that plays an oncogenic function in HNSCC progression. Analyzing HNSCC patients' data from the Cancer Genome Atlas (TCGA) indicates that the expression levels of SNX5 in HNSCC are significantly elevated compared to normal tissues. Furthermore, higher SNX5 expression correlates with a worse prognosis for HNSCC patients. These results suggest that SNX5 has an oncogenic role. Consistently, loss of SNX5 in HNSCC cells dramatically reduces colony formation and significantly decreases tumor growth in xenograft mouse models. SNX5 interacts with the tumor suppressor F-box/WD repeat-containing protein 7 (FBW7), an E3 ubiquitin ligase that mediates ubiquitination and degradation of oncoproteins such as c-Myc, NOTCH1, and Cyclin E1. By interacting with FBW7, SNX5 inhibits FBW7-mediated oncoproteins ubiquitination. In this way, SNX5 decreases the FBW7-mediated oncoproteins degradation to promote HNSCC progression.

Downregulation of CYB5D2 is associated with breast cancer progression

We report here that CYB5D2 is associated with tumor suppression function in breast cancer (BC). CYB5D2 expression was significantly reduced in tamoxifen resistant MCF7 cells and in MCF7 cell-derived xenografts treated with TAM. CYB5D2 overexpression induced apoptosis in MCF7 cells; CYB5D2 knockdown enhanced MCF7 cell proliferation. Using the TCGA and Curtis datasets within the Oncomine database, CYB5D2 mRNA expression was downregulated in primary BCs vs breast tissues and HER2-positive or triple negative BCs vs estrogen receptor (ER)-positive BCs. Using the TCGA and Metabric datasets (n = 817 and n = 2509) within cBioPortal, 660 and 4891 differentially expressed genes (DEGs) in relation to CYB5D2 were identified. These DEGs were enriched in pathways governing cell cycle progression, progesterone-derived oocyte maturation, oocyte-meiosis, estrogen-mediated S-phase entry, and DNA metabolism. CYB5D2 downregulation decreased overall survival (OS, p = 0.0408). A CYB5D2-derived 21-gene signature was constructed and robustly correlated with OS shortening (p = 5.72e-12), and independently predicted BC deaths (HR = 1.28; 95% CI 1.08–1.52; p = 0.004) once adjusting for known clinical factors. CYB5D2 reductions displayed relationship with mutations in PIK3CA, GATA3, MAP3K1, CDH1, TP53 and RB1. Impressively, 85% (560/659) of TP53 mutations occurred in the 21-gene signature-positive BC. Collectively, we provide the first evidence that CYB5D2 is a candidate tumor suppressor of BC.

Identification of Targetable Lesions in Anaplastic Thyroid Cancer by Genome Profiling

Anaplastic thyroid cancer (ATC) is a rare and extremely malignant tumor with no available cure. The genetic landscape of this malignancy has not yet been fully explored. In this study, we performed whole exome sequencing and the RNA-sequencing of fourteen cases of ATC to delineate copy number changes, fusion gene events, and somatic mutations. A high frequency of genomic amplifications was seen, including 29% of cases having amplification of CCNE1 and 9% of CDK6; these events may be targetable by cyclin dependent kinase (CDK) inhibition. Furthermore, 9% harbored amplification of TWIST1, which is also a potentially targetable lesion. A total of 21 fusion genes in five cases were seen, none of which were recurrent. Frequent mutations included TP53 (55%), the TERT promoter (36%), and ATM (27%). Analyses of mutational signatures showed an involvement of processes that are associated with normal aging, defective DNA mismatch repair, activation induced cytidine deaminase (AID)/apolipoprotein B editing complex (APOBEC) activity, failure of DNA double-strand break repair, and tobacco exposure. Taken together, our results shed new light on the tumorigenesis of ATC and show that a relatively large proportion (36%) of ATCs harbor genetic events that make them candidates for novel therapeutic approaches. When considering that ATC today has a mortality rate of close to 100%, this is highly relevant from a clinical perspective.

Fluoro-Chromogenic Labelling for Detection of MCM2 to Assess Proliferation Activity in HER2-amplified Breast Carcinomas

Minichromosome Maintenance Protein 2 (MCM2) is critical in initiating DNA replication during the cell division process. As expressed intensively in all phases of the active cell cycle, MCM2 has been proposed as a novel biomarker to determine cellular proliferation. We aimed at clarifying the prevalence and clinical significance of MCM2 in HER2-amplified breast cancer subtype. MCM2 expression was studied in 142 primary HER2-amplified breast carcinomas by applying a novel fluoro-chromogenic immunohistochemistry and tailored digital image analysis to determine labelling index (MCM2-LI). The presence of MCM2 was detected with HRP-conjugated polymer and visualized with 3, 3'-diaminobenzidine tetrahydrochloride, in cytokeratin (CK)-positive and Cy2-IgG-labelled breast cancer cells of epithelial origin. Stained slides were digitized by scanning sequentially under bright field (for MCM2) and fluorescence (for CK) illumination. Multilayer JPEG2000 images were analyzed with ImmunoRatio 2.5 (accessory in SlideVantage 1.2 software) utilizing its bright field and fluorescence image-blending mode to display MCM2-CK dual-positive cells. MCM2-LI was retrospectively compared with histopathologic characteristics and patients' clinical outcome. MCM2 protein-expressing cells (median MCM2-LI, 63.5%) were more frequent than those of Ki67 (median Ki67 labelling index, 33%). Significant correlations were found between high MCM2-LI, high Ki67 labelling index, negative hormone receptor (ER, PR) statuses, high grade of malignancy, and high cyclin E expression. MCM2-LI was not shown to be predictive of disease recurrence during the median follow-up of 5.3 years but was shown to be useful to distinguish aggressive-type HER2-amplified breast carcinomas with high malignancy grade and hormone receptor negativity. The fluoro-chromogenic double-labelling immunohistochemistry accompanied with digital image analysis provides an accurate carcinoma-specific determination of MCM2-LI on a single tumor section.

Clinical significance and biological roles of cyclins in gastric cancer

Background and aim

Cyclins have been reported to be overexpressed with poor prognosis in several human cancers. However, limited numbers of studies evaluated the expressions and prognostic roles of cyclins in gastric cancer (GC). We aim to evaluate the expressions and prognostic roles of cyclins. Also, further efforts were made to explore biological function of the differentially expressed cyclins.

Methods

Cyclins expressions were analyzed by Oncomine and The Cancer Genome Atlas datasets, and the prognostic roles of cyclins in GC patients were investigated by the Kaplan–Meier Plotter database. Then, a comprehensive PubMed literature search was performed to identify expression and prognosis of cyclins in GC. Biological functions of the differentially expressed cyclins were explored through Enrich R platform, and KEGG and transcription factor were analyzed.

Results

The expression levels of CCNA2 (cyclin A2), CCNB1 (cyclin B1), CCNB2 (cyclin B2), and CCNE1 (cyclin E1) mRNAs were identified to be significantly higher in GC tissues than in normal tissues in both Oncomine and The Cancer Genome Atlas datasets. High expressions of CCNA2, CCNB1, and CCNB2 mRNAs were identified to be related with poor overall survival in Kaplan–Meier Plotter dataset. Evidence from clinical studies showed that CCNB1 was related with overall survival in GC patients. Cyclins were associated with several biological pathways, including cell cycle, p53 signaling pathway, FoxO signaling pathway, viral carcinogenesis, and AMPK signaling pathway. Enrichment analysis also showed that cyclins interacted with some certain transcription factors, such as FOXM1, SIN3A, NFYA, and E2F4.

Conclusion

Based on our results, high expressions of cyclins were related with poor prognosis in GC patients. The above information might be useful for better understanding the clinical and biological roles of cyclins mRNA and guiding individualized treatments for GC patients.

Potential role of cyclin F mRNA expression in the survival of skin melanoma patients: Comprehensive analysis of the pathways altered due to cyclin F upregulation

Cyclin F is a part of the Skp, Cullin, F-box containing ligase complex. The activity of cyclin F includes cell cycle control, centrosome duplication and response to DNA damage. The cyclin F expression pattern is very similar to cyclin A, but cyclin F is an orphan cyclin without its cyclin-dependent kinase partner. There is little evidence concerning the role of cyclin F in cancer. In the present study, for the first time, we present analysis from The Cancer Genome Atlas (TCGA) data in the context of expression of cyclin F mRNA in melanoma patients. Our original in silico analysis, not published elsewhere before, revealed that high expression of cyclin F in melanoma patients is associated with worse overall survival. Cyclin F and ribonucleotide reductase family member 2 (RRM2) compose a functional axis responsible for nucleotide metabolism. Impairment in this pathway may contribute to increased DNA damage repair and drug resistance. Additionally, we analyzed the expression of RRM2 mRNA and discovered that high expression of RRM2 is associated with worse overall survival. To shed more light on cyclin F overexpression in melanoma, we analyzed all protein data available in the TCGA melanoma dataset. It was found that in patients with upregulated cyclin F mRNA, we noted increased activity of pathways related to cell cycle and DNA damage repair. These data will support further in vitro and in vivo studies on the involvement of cyclin F in skin cutaneous melanoma.

Prognostic Values of CCNE1 Amplification and Overexpression in Cancer Patients: A Systematic Review and Meta-analysis

A number of studies revealed that CCNE1 copy number amplification and overexpression (on mRNA or protein expression level) were associated with prognosis of diverse cancers, however, the results were inconsistent among studies. So we conducted this systematic review and meta-analysis to investigate the prognostic values of CCNE1 amplification and overexpression in cancer patients. PubMed, Cochrane library, Embase, CNKI and WanFang database (last update by February 15, 2018) were searched for literatures. A total of 20 studies were included and 5 survival assessment parameters were measured in this study, which included overall survival (OS), progression free survival (PFS), recurrence free survival (RFS), cancer specific survival (CSS) and distant metastasis free survival (DMFS). Pooled analyses showed that CCNE1 amplification might predict poor OS (HR=1.59, 95% CI: 1.05-2.40, p=0.027) rather than PFS (HR=1.49, 95% CI: 0.83-2.67, p=0.177) and RFS (HR=0.982, 95% CI: 0.2376-4.059, p=0.9801) in various cancers; CCNE1 overexpression significantly correlated with poor OS (HR=1.52, 95% CI: 1.05-2.20, p=0.027), PFS (HR=1.20, 95% CI: 1.07-1.34, p=0.001) and DMFS (HR=1.62, 95% CI: 1.09-2.40, p=0.017) rather than RFS (HR=1.68, 95% CI: 0.81-3.50, p=0.164) and CSS (HR=1.54, 95% CI: 0.74-3.18, p=0.246). On the whole, these results indicated CCNE1 amplification and overexpression were associated with poor survival of patients with cancer, suggesting that CCNE1 might be an effective prognostic signature for cancer patients.

USP27-mediated Cyclin E stabilization drives cell cycle progression and hepatocellular tumorigenesis

Overexpression of Cyclin E has been seen in many types of cancers. However, the underlying mechanism remains enigmatic. Herein, we identified ubiquitin-specific peptidase 27 (USP27) as a Cyclin E interactor. We found that USP27 promoted Cyclin E stability by negatively regulating its ubiquitination. In addition, suppression of USP27 expression resulted in the inhibition of the growth, migration, and invasion of hepatocellular carcinoma. Furthermore, we detected a positive correlation between USP27 and Cyclin E expression in hepatocellular carcinoma tissues. Finally, we found that USP27 expression is inhibited by 5-fluorouracil (5-FU) treatment and USP27 depletion sensitizes Hep3B cells to 5-FU-induced apoptosis. USP27-mediated Cyclin E stabilization is involved in tumorigenesis, suggesting that targeting USP27 may represent a new therapeutic strategy to treat cancers with aberrant overexpression of Cyclin E protein.

Protein expression patterns of cell cycle regulators in operable breast cancer

Background-Aim

To evaluate the prognostic role of elaborate molecular clusters encompassing cyclin D1, cyclin E1, p21, p27 and p53 in the context of various breast cancer subtypes.

Methods

Cyclin E1, cyclin D1, p53, p21 and p27 were evaluated with immunohistochemistry in 1077 formalin-fixed paraffin-embedded tissues from breast cancer patients who had been treated within clinical trials. Jaccard distances were computed for the markers and the resulted matrix was used for conducting unsupervised hierarchical clustering, in order to identify distinct groups correlating with prognosis.

Results

Luminal B and triple-negative (TNBC) tumors presented with the highest and lowest levels of cyclin D1 expression, respectively. By contrast, TNBC frequently expressed Cyclin E1, whereas ER-positive tumors did not. Absence of Cyclin D1 predicted for worse OS, while absence of Cyclin E1 for poorer DFS. The expression patterns of all examined proteins yielded 3 distinct clusters; (1) Cyclin D1 and/or E1 positive with moderate p21 expression; (2) Cyclin D1 and/or E1, and p27 positive, p53 protein negative; and, (3) Cyclin D1 or E1 positive, p53 positive, p21 and p27 negative or moderately positive. The 5-year DFS rates for clusters 1, 2 and 3 were 70.0%, 79.1%, 67.4% and OS 88.4%, 90.4%, 78.9%, respectively.

Conclusions

It seems that the expression of cell cycle regulators in the absence of p53 protein is associated with favorable prognosis in operable breast cancer.

Cell Cycle Regulation in Treatment of Breast Cancer

Cell cycle progression and cell proliferation are under precise and orchestrated control in normal cells. However, uncontrolled cell proliferation caused by aberrant cell cycle progression is a crucial characteristic of cancer. Understanding cell cycle progression and its regulation sheds light on cancer treatment. Agents targeting cell cycle regulators (such as CDKs) have been considered as promising candidates in cancer treatment. Although the first-generation pan-CDK inhibitors failed in clinical trials because of their adverse events and low efficacy, new selective CDK 4/6 inhibitors showed potent efficacy with tolerable safety in preclinical and clinical studies. Here we will review the mechanisms of cell cycle regulation and targeting key cell cycle regulators (such as CDKs) in breast cancer treatment. Particularly, we will discuss the mechanism of CDK inhibitors in disrupting cell cycle progression, the use of selective CDK4/6 inhibitors in treatment of advanced, hormone receptor (HR)-positive postmenopausal breast cancer patients, and other clinical trials that aim to extend the utilization of these agents.