Cyclin H expression is increased in GIST with very-high risk of malignancy

Global fungal-host interactome mapping identifies host targets of candidalysin

Candidalysin, a cytolytic peptide toxin secreted by the human fungal pathogen Candida albicans, is critical for fungal pathogenesis. Yet, its intracellular targets have not been extensively mapped. Here, we performed a high-throughput enhanced yeast two-hybrid (HT-eY2H) screen to map the interactome of all eight Ece1 peptides with their direct human protein targets and identified a list of potential interacting proteins, some of which were shared between the peptides. CCNH, a regulatory subunit of the CDK-activating kinase (CAK) complex involved in DNA damage repair, was identified as one of the host targets of candidalysin. Mechanistic studies revealed that candidalysin triggers a significantly increased double-strand DNA breaks (DSBs), as evidenced by the formation of γ-H2AX foci and colocalization of CCNH and γ-H2AX. Importantly, candidalysin binds directly to CCNH to activate CAK to inhibit DNA damage repair pathway. Loss of CCNH alleviates DSBs formation under candidalysin treatment. Depletion of candidalysin-encoding gene fails to induce DSBs and stimulates CCNH upregulation in a murine model of oropharyngeal candidiasis. Collectively, our study reveals that a secreted fungal toxin acts to hijack the canonical DNA damage repair pathway by targeting CCNH and to promote fungal infection.

The role of cyclins in the development and progression of prostate cancer

The role of cyclins in hormone-dependent neoplasms is crucial in the development of the disease that is resistant to first-line therapy, as the example of breast cancer shows. However, in prostate cancer, cyclins are studied to a lesser extent. There are some well-described molecular pathways, including cyclins A1 and D1 signaling, however the role of other cyclins, e.g., D2, D3, E, and H, still requires further investigation. Recent studies indicate that cyclins regulate various cellular processes, not only the cell cycle. Furthermore, they remain in cross-talk with many other signaling pathways, e.g., MAPK/ERK, PI3K/Akt, and Notch. The androgen signaling axis, which is pivotal in prostate cancer progression, interferes with cyclin pathways at many levels. This article summarizes current knowledge on the influence of cyclins on prostate cancer progression by describing interactions between the androgen receptor and cyclins, as well as mechanisms underlying the development of resistance to currently used therapies.

Cyclin H Regulates Lung Cancer Progression as a Carcinoma Inducer

Introduction

Studies have previously shown that Cyclin H (CCNH) is involved in the tumorigenesis and development of many cancers. The increasing research in CCNH is associated with the poor prognosis of most human cancers. Early diagnosis and clinical treatment are still the main challenges for lung cancer treatment. However, the exact role of CCNH in the tumorigenesis of lung cancer remains unclear.

Methods

The Tumor Genome Atlas (TCGA) database and the Clinical Proteomics Tumor Analysis Association (CPTAC) database were analyzed to detect key genes that might play an important role in lung cancer. The biological functions of CCNH were further revealed through bioinformatics experiments. The Kaplan-Meier method was applied to explore the relationship between CCNH expression and prognosis. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to detect the expression levels of CCNH in 6 lung cancer tissues and 3 cancer cell lines. The effect of CCNH expression on lung cancer progression was studied by in vitro functional experiments.

Results

Database analysis screened out candidate oncogenes, and CCNH was of great significance to the tumorigenesis of lung cancer. The higher the expression of CCNH was, the lower the survival rate of lung cancer patients were. The qRT-PCR data illustrated that the CCNH expression level was largely increased in lung cancer tissues and cells. The reduction of CCNH inhibited cell proliferation, invasion, and migration.

Conclusion

CCNH was related to poor prognosis, suggesting that CCNH regulated the tumorigenesis and development of lung cancer. Our study suggested that CCNH was a promising biomarker and target in the treatment of lung cancer.

Cyclin H predicts the poor prognosis and promotes the proliferation of ovarian cancer

Background

Cell cycle dysregulation plays a key role in the pathogenesis of malignant tumors. As a part of the CDK-activating kinase (CAK) trimeric complex, cyclin H is necessary to regulate the cell cycle and proliferation. This investigation aims to characterize the clinical significance and the biological functions of cyclin H in ovarian cancer.

Methods

Immunohistochemical staining was performed on 60 ovarian cancer cases, and a correlation between cyclin H expression and the clinical characteristics of ovarian cancer was analyzed. The function of cyclin H in ovarian cancer was further explored using HO8910 cells and a subcutaneous xenograft model of nude mice.

Result

Cyclin H was slightly expressed in grade 1 ovarian cancer but highly expressed in grade 2 and grade 3 cancerous tissues. The Spearman's rank correlation analysis showed that the expression of cyclin H is positively correlated with the tumor grade, the FIGO stage, histological grade, and the peritoneal metastasis of ovarian cancer and is also positively correlated with the Ki67 and p-CDK2 in ovarian cancer. Additionally, we found that the five-year survival rate was higher in patients expressing low cyclin H than those expressing high cyclin H. Further, knockdown of cyclin H was achieved using an shRNA in HO8910 ovarian cancer cell line. Silencing cyclin H resulted in a G1/S cell cycle arrest in ovarian cancer cells suppressing its growth. The Ki67 expression was also decreased in cyclin H silenced ovarian cancer.

Conclusion

These results suggest that high expression of cyclin H predicts the poor prognosis and promotes the growth of ovarian cancer by regulating the cell cycle.

The role of FBXW7, a cell-cycle regulator, as a predictive marker of recurrence of gastrointestinal stromal tumors

BACKGROUND

Few reliable prognostic markers have been established despite elucidation of the molecular mechanisms of gastrointestinal stromal tumor (GIST) development. We evaluated F-box and WD repeat domain-containing 7 (FBXW7), a cell-cycle-regulating and tumor suppressor, in GISTs. We aimed to determine the clinical relevance of FBXW7 in GISTs and characterize the molecular mechanism of FBXW7 in a GIST cell line.

METHODS

We measured FBXW7 expression in 182 GIST cases, correlated the expression levels with clinicopathological features, and characterized the molecular mechanism underlying suppressed FBXW7 expression in GIST cells in vitro.

RESULTS

Of the 182 GISTs, 98 (53.8%) and 84 (46.2%) were categorized in the high and low FBXW7 expression groups, respectively. Compared with the high FBXW7 expression group, the low expression group showed a significantly poorer prognosis in terms of recurrence-free (P = 0.01) and overall (P = 0.03) survival. FBXW7 expression was a significant independent factor affecting the 10-year recurrence-free survival rate (P = 0.04). In vitro, FBXW7-specific siRNAs enhanced c-myc and Notch 1 protein expression and upregulated cell proliferation, invasion, and migration.

CONCLUSION

FBXW7 is a potential predictive marker of recurrence after curative resection of GISTs. FBXW7 expression may help identify patients benefitting from adjuvant therapy more precisely compared with a conventional risk stratification model.

The expression of MDM2 in gastrointestinal stromal tumors: immunohistochemical analysis of 35 cases

Background

Gastrointestinal stromal tumors (GIST) are the most common primary mesenchymal tumors of the digestive system. The assessment of their biological behavior still remains a scientific challenge. To date, there are no well-established biological prognostic markers of GIST. Our aim is to study the expression of the MDM2 oncoprotein in GIST through an immunohistochemical analysis.

Methods

It was a retrospective study of 35 cases of GIST diagnosed from 2009 to 2012 in the department of pathology of Hassan II university hospital, Fès, Morocco. MDM2 immunohistochemical staining was performed on archival paraffin-embedded and formalin-fixed specimens (with a threshold of nuclear positivity > 10%). Analysis of correlations between MDM2 immunoexpression and clinicopathological features of GIST has been performed.

Results

The mean age was 55.23 years (range 25–84 years) with a male predominance (sex ratio = 1.5). The stomach was the main site of GIST, with 17 cases (48.57%) followed by the small bowel (9 cases, 25.71%). The spindle cell type GIST was the most frequent morphological variant (29 cases, 82.85%). Tumor necrosis was present in 8 cases (22.85%). Two patients (5.71%) had very low risk GIST, 5 (14.28%) had low risk GIST, 7 patients (20%) had intermediate risk tumors. The remaining 21 cases (60%) had high risk GIST. At the time of diagnosis, 9 patients (25.71%) had metastatic tumors. At immunohistochemical analysis, 40% of cases (14 patients) stained positive for MDM2. Of these MDMD2-positive tumors, 11/14 (78.57%) had high risk tumors and 8/14 cases (57.14%) presented with metastatic GIST. MDM2 positivity was significantly associated with the metastatic status (p = 0.001).

Conclusion

The current study suggests that MDM2 immunohistochemical expression is a negative histoprognostic factor in GIST with a statistically significant correlation with metastasis.

Effects of 12C6+ heavy ion beam irradiation on the p53 signaling pathway in HepG2 liver cancer cells

The heavy ion beam is considered to be the ideal source for radiotherapy. The p53 tumor suppressor gene senses DNA damage and transducts intracellular apoptosis signals. Previous reports showed that the heavy ion beam can trigger complex forms of damage to cellular DNA, leading to cell cycle arrest and apoptosis of HepG2 human liver cancer cells; however, the mechanisms remains unclear fully. In order to explore whether the intrinsic or extrinsic pathway participates this process, HepG2 cells were treated with 12C6+ HIB irradiation at doses of 0 (control), 1, 2, 4, and 6 Gy with various methods employed to understand relevant mechanisms, such as detection of apoptosis, cell cycle, and Fas expression by flow cytometry, analysis of apoptotic morphology by electron microscopy and laser scanning confocal microscopy, and screening differentially expressed genes relating to p53 signaling pathway by PCR-array assay following with any genes confirmed by western blot analysis. This study showed that 12C6+ heavy ion beam irradiation at a dose of 6 Gy leads to endogenous DNA double-strand damage, G2/M cell cycle arrest, and apoptosis of human HepG2 cells via synergistic effect of the extrinsic and intrinsic pathways. Differentially expressed genes in the p53 signaling pathway related to DNA damage repair, apoptosis, cycle regulation, metastasis, deterioration and radioresistance were also discovered. Consequently, the expressions of Fas, TP53BP2, TP53AIP1, and CASP9 were confirmed upregulated after 12C6+ HIB irradiation treatment. In conclusion, this study demonstrated the mechanisms of inhibition and apoptosis induced by 12C6+ heavy ion beam irradiation on HepG2 cancer cells is mediated by initiation of the biological function of p53 signaling pathway including extrinsic and intrinsic apoptosis pathway.

Positive cyclin T expression as a favorable prognostic factor in treating gastric gastrointestinal stromal tumors

Positive transcriptional elongation factor b (P-TEFb) contains the catalytic subunit cyclin-dependent kinase 9 (Cdk9) and the regulatory subunit cyclin T. Cyclin T1 and Cdk9 are the key factors of the PTEFb pathways and are overexpressed in the human head and neck carcinoma cell line. However, there have been limited studies regarding the role of cyclin T1 and Cdk9 in gastric gastrointestinal stromal tumors (GISTs). The aim of the present study was to assess the association between cyclin T1 and Cdk9 and their clinical significance in gastric GISTs. A total of 30 gastric GIST patients who underwent either laparoscopic or laparotomic partial gastrectomy were enrolled in the study. The surgical tissue slides were stained with Cdk9 and cyclin T1 antibodies, and the immunohistochemistry scores and disease-free survival (DFS) were analyzed. Ten patients were cyclin T1-positive, and 20 were negative. All 11 patients with recurrent tumors or distant metastases were cyclin T1-negative patients. Old age, large tumor size, a high Ki67 IHC staining score, high mitotic count and negative cyclin T1 staining revealed a worse clinical outcome in univariate analysis. By contrast, the Cdk9 score was not associated with clinical parameters. The Kaplan-Meier survival curve illustrated that the DFS rate of the patients with negative cyclin T1 staining was significantly lower than that of the patients with positive cyclin T1 staining. Positive expression of cyclin T1 was a good prognostic factor in patients with gastric GISTs.

Cyclins and cell cycle control in cancer and disease

Cyclin D1 overexpression is found in more than 50% of human breast cancers and causes mammary cancer in transgenic mice. Dysregulation of cyclin D1 gene expression or function contributes to the loss of normal cell cycle control during tumorigenesis. Recent studies have demonstrated that cyclin D1 conducts additional specific functions to regulate gene expression in the context of local chromatin, promote cellular migration, and promote chromosomal instability. It is anticipated that these additional functions contribute to the pathology associated with dysregulated cyclin D1 abundance. This article discusses evidence that examines the functional roles that cyclin D1 may play in cancer with an emphasis on other cyclin family members that also may contribute to cancer and disease in a similar fashion.

Genomic Grade Index predicts postoperative clinical outcome of GIST

BACKGROUND

Prognosis of localised gastrointestinal stromal tumour (GIST) is heterogeneous, notably for patients with AFIP intermediate or high risk of relapse, who are candidates to adjuvant imatinib. We hypothesised that gene expression profiles might improve the prognostication and help to refine the indications for imatinib.

METHODS

We collected gene expression and histoclinical data of 146 pre-treatment localised GIST samples treated with surgery alone. We searched for a gene expression signature (GES) predictive for relapse-free survival (RFS) and compared its performances to that of three published prognostic proliferation-based GES (Genomic Grade Index (GGI), 16-Kinase, and CINSARC) and AFIP classification. We also analysed a data set from 28 patients with advanced GIST treated with neo-adjuvant imatinib.

RESULTS

We identified a 275-gene GES (gene expression signature) predictive of RFS in a learning set and validated its robustness in an independent set. However, the GGI outperformed its prognostic performances, and those of the two other signatures and the AFIP intermediate-risk classification in two independent tests sets in uni- and multivariate analyses. Importantly, GGI could split the AFIP intermediate/high-risk samples into two groups with different RFS. Genomic Grade Index 'high-risk' tumours were more proliferative and genetically unstable than 'low-risk' tumours, and more sensitive to imatinib.

CONCLUSION

GGI refines the prediction of RFS in localised GIST and might help tailor adjuvant imatinib.

Evaluation of malignancy using Ki-67, p53, EGFR and COX-2 expressions in gastrointestinal stromal tumors

AIM

To investigate the role of expressions of Ki-67, p53, epidermal growth factor receptor (EGFR) and cyclooxygenase-2 (COX-2) in gastrointestinal stromal tumor (GIST) grading and prognosis.

METHODS

Tumor tissue was collected retrospectively from 96 patients with GIST. Antibodies against Ki-67, p53, EGFR and COX-2 were used for immunohistochemical staining. Tumor grading was designated according to a consensus system and the staining was quantified in 3 categories for each antibody in the statistical analysis.

RESULTS

The Ki-67 expression in GISTs was significantly associated with the size of the tumors, mitotic rate and the risk of malignancy (χ(2) = 15.51, P = 0.02; χ(2) = 22.27, P < 0.001; χ(2) = 20.05; P < 0.001). The p53 expression was also significantly correlated with mitotic rate and the risk of malignancy (χ(2) = 9.92, P = 0.04; χ(2) = 9.97; P = 0.04). Over-expression of Ki-67 was strongly correlated with poor survival (χ(2) = 10.44, P = 0.006), but no correlation was found between the expression of p53, EGFR or COX-2 and survival. Multivariate analysis further demonstrated that Ki-67 expression (relative risk = 15.78, 95% CI: 4.25-59.37) could be used as an independent prognostic value for GIST patients. Adjuvant imatinib therapy could improve clinical outcomes in the patients with high risk and intermediate risk of recurrence after complete tumor resections (median survival time: 52 mo vs 37 mo, χ(2) = 7.618, P = 0.006).

CONCLUSION

Our results indicated that the expression of Ki-67 could be used as an independent prognostic factor for GIST patients.

Correlation of ER81 expression with clinicopathological parameters and expression of CD117 and ki67 in GISTs

AIM: To investigate the correlation of ER81 protein expression with clinicopathological parameters and expression of CD117 and ki67 in gastrointestinal stromal tumors (GISTs).

METHODS: Immunohistochemistry was performed to detect the expression of ER81 in 17 cases of normal gastric mucosal tissue specimens and 80 cases of GISTs tissue specimens. The correlation of ER81 expressio with age, NIH risk, CD117, and ki67 was then analyzed.

RESULTS: The positive rate of ER81 expression was significantly lower in GISTs than in normal gastric tissue (11.7% vs 75%, P < 0.05). ER81 expression had no relationship with sex or age, but was associated with NIH risk classification (P < 0.05). ER81 expression was positively correlated with NIH risk levels. ER81 expression was also correlated with CD117 and ki67 expression in GISTs (both P < 0.05).

CONCLUSION: ER81 expression is associated with the incidence and risk level of GISTs. ER81 expression also correlates with CD117 and ki67 expression. ER81 may represent a new target for molecular diagnosis of GISTs.

Gastrointestinal stromal tumours: origin and molecular oncology

Gastrointestinal stromal tumours (GISTs) are a paradigm for the development of personalized treatment for cancer patients. The nearly simultaneous discovery of a biomarker that is reflective of their origin and the presence of gain-of-function kinase mutations in these tumours set the stage for more accurate diagnosis and the development of kinase inhibitor therapy. Subsequent studies of genotype and phenotype have led to a molecular classification of GIST and to treatment optimization on the basis of molecular subtype. The study of drug-resistant tumours has advanced our understanding of kinase biology, enabling the development of novel kinase inhibitors. Further improvements in GIST treatment may require targeting GIST stem cell populations and/or additional genomic events.