Psf3 is a prognostic biomarker in lung adenocarcinoma

Single-cell transcriptomics reveals intestinal cell heterogeneity and identifies Ep300 as a potential therapeutic target in mice with acute liver failure

Acute liver failure (ALF) is a severe life-threatening disease associated with the disorder of the gut-liver axis. However, the cellular characteristics of ALF in the gut and related therapeutic targets remain unexplored. Here, we utilized the D-GALN/LPS (D/L)-induced ALF model to characterize 33,216 single-cell transcriptomes and define a mouse ALF intestinal cellular atlas. We found that unique, previously uncharacterized intestinal immune cells, including T cells, B cells, macrophages, and neutrophils, are responsive to ALF, and we identified the transcriptional profiles of these subsets during ALF. We also delineated the heterogeneity of intestinal epithelial cells (IECs) and found that ALF-induced cell cycle arrest in intestinal stem cells and activated specific enterocyte and goblet cell clusters. Notably, the most significantly altered IECs, including enterocytes, intestinal stem cells and goblet cells, had similar activation patterns closely associated with inflammation from intestinal immune activation. Furthermore, our results unveiled a common Ep300-dependent transcriptional program that coordinates IEC activation during ALF, which was confirmed to be universal in different ALF models. Pharmacological inhibition of Ep300 with an inhibitor (SGC-CBP30) inhibited this cell-specific program, confirming that Ep300 is an effective target for alleviating ALF. Mechanistically, Ep300 inhibition restrained inflammation and oxidative stress in the dysregulated cluster of IECs through the P38-JNK pathway and corrected intestinal ecology by regulating intestinal microbial composition and metabolism, thereby protecting IECs and attenuating ALF. These findings confirm that Ep300 is a novel therapeutic target in ALF and pave the way for future pathophysiological studies on ALF.

DNA replication: Mechanisms and therapeutic interventions for diseases

Accurate and integral cellular DNA replication is modulated by multiple replication-associated proteins, which is fundamental to preserve genome stability. Furthermore, replication proteins cooperate with multiple DNA damage factors to deal with replication stress through mechanisms beyond their role in replication. Cancer cells with chronic replication stress exhibit aberrant DNA replication and DNA damage response, providing an exploitable therapeutic target in tumors. Numerous evidence has indicated that posttranslational modifications (PTMs) of replication proteins present distinct functions in DNA replication and respond to replication stress. In addition, abundant replication proteins are involved in tumorigenesis and development, which act as diagnostic and prognostic biomarkers in some tumors, implying these proteins act as therapeutic targets in clinical. Replication-target cancer therapy emerges as the times require. In this context, we outline the current investigation of the DNA replication mechanism, and simultaneously enumerate the aberrant expression of replication proteins as hallmark for various diseases, revealing their therapeutic potential for target therapy. Meanwhile, we also discuss current observations that the novel PTM of replication proteins in response to replication stress, which seems to be a promising strategy to eliminate diseases.

MicroRNA-133a-3p Inhibits Lung Adenocarcinoma Development and Cisplatin Resistance through Targeting GINS4

GINS subunit complex 4 (GINS4) is fundamental to DNA replication and G1/S phase transition of the cell cycle in eukaryotes. Further, recent studies implied that GINS4 can mediate the progression of several tumors, but its mechanism in lung adenocarcinoma (LUAD) is not clarified. Therefore, the role of GINS4 in LUAD was explored. miR-133a-3p and GINS4 mRNA expression were tested through qRT-PCR. Protein levels of the two genes were assayed by Western blot. Their targeting relationship was predicted and verified by bioinformatics prediction and dual-luciferase analysis. The functions of miR-133a-3p and GINS4 in LUAD were evaluated by Transwell, wound healing, CCK-8, and flow cytometry assays. MTT assay and caspase-3 activity detection were utilized to measure the regulation of miR-133a-3p/GINS4 in the cisplatin sensitivity of LUAD cells. The results showed that GINS4 was highly expressed in LUAD cells (p < 0.05). miR-133a-3p, the upstream gene of GINS4 in LUAD, negatively mediated GINS4 expression. Moreover, overexpressing GINS4 enhanced the proliferative, migratory, and invasive abilities of LUAD cells and inhibited cell apoptosis and the sensitivity to cisplatin, while overexpressing miR-133a-3p caused the contrary results. However, the promoting effects of GINS4 overexpression on LUAD could be offset by miR-133a-3p overexpression. miR-133a-3p could regulate malignant behaviors and cisplatin sensitivity of LUAD cells through negatively regulating GINS4. In conclusion, our findings demonstrated that GINS4 was overexpressed in LUAD and promoted the malignant behavior of LUAD cells. Moreover, miR-133a-3p could negatively regulate GINS4, thereby suppressing the malignant progression and increasing the cisplatin sensitivity of LUAD.

Comprehensive analysis of GINS subunits prognostic value and ceRNA network in sarcoma

Background: The GINS complex, composed of GINS1/2/3/4 subunits, is an essential structure of Cdc45-MCM-GINS (CMG) helicase and plays a vital role in establishing the DNA replication fork and chromosome replication. Meanwhile, GINS genes have been associated with the poor prognosis of various malignancies. However, the abnormal expression of GINS genes and their diagnostic and prognostic value in sarcomas (SARC) remain unclear.

Methods: Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), Kaplan-Meier Plotter, Cancer cell line encyclopedia (CCLE), The University of Alabama at Birmingham Cancer Data Analysis Portal (UALCAN), R studio, and Tumor Immune Estimation Resource (TIMER) were used to analyze the expression profiles, prognostic value, biological function, ceRNA, and immune infiltration associated with GINS genes in sarcomas.

Results: We found that GINS1/2/3/4 genes exhibited significantly upregulated transcription levels in SARC samples compared to non-tumor tissues and exhibited high expression levels in sarcoma cell lines. In addition, SARC patients with increased expression levels of GINS1/2/3/4 showed poorer survival rates. Immune infiltration analysis showed that GINS subunits were closely associated with the infiltration of immune cells in sarcomas.

Conclusion: Our research identified GINS subunits as potential diagnostic and prognostic biological targets in SARC and elucidated their underlying effects in the genesis and progression of SARC. These results may provide new opportunities and research directions for targeted sarcoma therapy.

Combined analysis of expression, prognosis and immune infiltration of GINS family genes in human sarcoma

Objective: This study was undertaken to explore the expression and prognostic value of GINS family in human sarcoma, as well as the association between the expression levels of the GINS family and sarcoma immune infiltration.

Results: We discovered that the mRNA expression levels of GINS1, GINS2, GINS3, and GINS4 were all higher in the majority of tumor tissues than in normal samples, of course, including sarcoma. Through the CCLE, all the four members expression were observed in high levels in sarcoma cell lines. In Gene Expression Profiling Analysis (GEPIA) and Kaplan-Meier Plotter, our results indicated that the poor overall survival (OS), disease-free survival (DFS) and relapse free survival (RFS) were tightly associated with the increased expression of GINS genes. In TIMER database, we found that highly expressed GINS was significantly correlated with the low infiltration level of CD4+ T cell and macrophage.

Conclusions: The four GINS family members were all the prognostic biomarkers for the prognosis of human sarcoma and can reduce the level of immune cell infiltration in the sarcoma microenvironment.

Methods: In terms of the expression levels of mRNA for GINS family members, a particular contrast in various cancers, especially human sarcoma, was conducted through ONCOMINE and GEPIA and CCLE databases. Kaplan-Meier Plotter was used to identify the prognostic value of GINS family in sarcoma. The relationship between the expression level of GINS and the infiltration of immune cells was analyzed in TIMER database.

Expression and prognosis analysis of GINS subunits in human breast cancer

ABSTRACT

GINS subunits, a protein complex composed of GINS1, GINS2, GINS3 and GINS4 in the human genome and the expression level of each GINS subunits plays an important role in different human cancers. As one of the most common malignancies after lung cancer in the world, precise biomarkers for early diagnosis and treatment in breast cancer are important. The purpose of our study was to elucidate the expression and prognostic value of GINS subunits in breast cancer.The purpose of present study was to explore the expression level of GINS subunits in breast cancer patients.In the present study, we investigated the gene alteration, gene expression and potential prognostic value of GINS subunits by using the Gene Expression Profiling Interactive Analysis (GEPIA), UALCAN, cBioPortal, and bc-GenExMiner databases. Then, the GeneMANIA database was used to show the genes that associated with GINS subunits. Furthermore, gene ontology pathway analysis was conducted by using the Metascape database. Finally, immune infiltration analysis in GINS subunits were evaluated using the Tumor Immune Estimation Resource (TIMER) database.Our analyses demonstrated that the expression levels of different GINS subunits were different between breast cancer and normal breast tissues. The expression levels of GINS1, GINS2, and GINS4 were significantly higher in breast cancer tissues than in normal tissues. Survival analysis revealed that increased the expression levels of GINS subunits were associated with poor prognoses in all patients with breast cancer. Gene ontology pathway enrichment analysis of the GINS subunits suggested that GINS subunits involved in pathways including the cell cycle checkpoint, DNA replication and other meaningful signaling pathways.We systemically analyzed the expression, prognostic, clinicopathologic values, and potential functional networks of GINS subunits in breast cancer. Our findings showed that individual GINS subunits could be new potential prognostic biomarkers for breast cancer. However, further verification studies are still needed to prove the clinical value of GINS subunits in breast cancer patients.

Expression Profile of GINS Complex Predicts the Prognosis of Pancreatic Cancer Patients

Background

The GINS complex has been implicated in the prognosis of various cancers. It comprises four subunits, encoded by GINS1, GINS2, GINS3, and GINS4 genes. Based on the current understanding, no report exists on the role of the GINS complex in pancreatic cancer.

Methods

We employed various bioinformatics databases including GEPIA, UALCAN, GEPIA2, and Kaplan Meier Plotter to identify the expression profile of the four genes (GINS1, GINS2, GINS3, and GINS4), their correlation with pancreatic cancer grade as well as their prognostic value of in pancreatic cancer. Western blotting and qRT-PCR analyses were conducted to verify the expression profiles of the four genes in pancreatic cancer. CCK8 and EdU cell experiments were conducted to reveal the role played by the four genes in pancreatic cancer cell proliferation.

Results

Based on GEPIA, Western blotting, and qRT-PCR analyses, all the four genes in the GINS complex were overexpressed in pancreatic cancer. Notably, the expression of each member was significantly associated with pancreatic cancer grade. The prognostic analysis revealed that not only the whole GINS complex but also each individual were prognostic biomarkers for pancreatic cancer. CCK8 and EdU experiments demonstrated that inhibition of the expression of each GINS member lowered pancreatic cancer cell proliferation.

Conclusion

This work implicated GINS1, GINS2, GINS3, and GINS4 genes as critical prognostic markers for pancreatic cancer.

Psf3 as a possible biomarker of postoperative chemotherapy for patients with early pulmonary adenocarcinoma

BACKGROUND

Partner of Sld five 3 (Psf3) is a member of the heterotetrameric complex that consists of SLD5, Psf1, Psf2, and Psf3. We have shown in previous studies that high Psf3 expression was a poor prognostic marker for pulmonary adenocarcinoma. Here, we statistically evaluated the relationship between clinicopathologic factors and Psf3 expression in stage I pulmonary adenocarcinoma.

METHODS

A total of 583 patients who had undergone complete resection of stage I pulmonary adenocarcinoma from January 2002 to December 2009 were included in the study. Tissue microarrays were performed, and the resected tumors were divided into groups according to Psf3 expression.

RESULTS

Of 583 patients, high expression of Psf3 was observed in 211 (36.2%) and low expression of Psf3 observed in 372 (63.8%) patients. Among stage I patients, the five-year survival rate was 76.7% in the Psf3 high expression group and 90.9% in the Psf3 low expression group (P < 0.0001). On multivariate analysis, Psf3 was found to be the independent prognostic factor. Among stage I patients in the Psf3 high expression group, a significantly greater five-year survival rate was observed in patients who received postoperative chemotherapy with tegafur-uracil than in those who underwent surgery alone (P < 0.0001). In contrast, among stage I patients in the Psf3 low expression group, no difference was found in the five-year survival, regardless of the presence or absence of tegafur-uracil (P = 0.873).

CONCLUSION

The Psf3 expression was an independent prognostic factor and could be a biomarker of adjuvant tegafur-uracil for stage I pulmonary adenocarcinoma.

KEY POINTS

Significant findings of the study: The Psf3 expression could be a biomarker of adjuvant tegafur-uracil administration for stage I pulmonary adenocarcinoma.

WHAT THIS STUDY ADDS

Appropriate patients of adjuvant chemotherapy for stage I pulmonary adenocarcinoma using Psf3 expression could be selected.

Up-regulated and interrelated expressions of GINS subunits predict poor prognosis in hepatocellular carcinoma

The GINS complex is one of the core components of the eukaryotic replicative helicase CMG (Cdc45–MCM helicase–GINS) complex that serves as the replicative helicase unwinding duplex DNA ahead of moving replication fork during chromosome duplication. Many studies have highlighted the important functions amongst GINS subunits in various cancers. Nevertheless, the functions and prognostic roles of distinct GINS subunits in hepatocellular carcinoma (HCC) were largely unexplored. In the present study, we reported the prognostic values of GINS subunits in HCC patients through analysis of several databases, including Oncomine, (TCGA), and Kaplan–Meier Plotter (KMPlotter). We found that mRNA expressions of all GINS subunits were significantly up-regulated in HCC tumor than in non-tumor liver tissues. Survival analysis revealed that elevated expression of individual GINS subunit predicts a poor overall survival (OS) in all HCC patients. When sorting the patients by gender, the correlation between elevated expression of individual GINS subunit and poor OS remains significant in male patient subgroup, but not in female patient subgroup. Additionally, we found that co-overexpression of all GINS subunits was significantly associated with a higher hazard ratio, suggesting the GINS complex may co-operate to promote HCC progression. Indeed, their expressions were highly correlated with each other in the same cohort and TRANSFAC analysis revealed that four transcription factors including C/EBPα, Oct-1, Sp1, and USF may serve as common transcription factors binding to the promoters of all four GINS subunits. Therefore, we propose that individual GINS subunit or GINS complex as a whole could be potential prognostic biomarkers for HCC.

Clinicopathological significance of PSF3 expression in uterine endometrial carcinomas

PSF3 (Partner of SLD Five 3) is a member of the heterotetrameric complex termed GINS. Previous studies have shown that PSF3 is up-regulated in several cancers and is associated with tumor malignancy. However, the clinicopathological significance of PSF3 expression in endometrial lesions is still poorly understood. To investigate whether PSF3 could serve as a useful biomarker for endometrial carcinomas, we performed immunohistochemical analysis of PSF3 expression. In 155 cases of endometrial carcinomas (ECs), the mean tumor proportion score of PSF3 expression was 30.7% in G1 endometrioid carcinoma, 55.0% in G2 endometrioid carcinoma, 59.0% in G3 endometrioid carcinoma, and 58.9% in nonendometrioid carcinomas. In 25 cases of atypical hyperplasia, the mean tumor proportion score of PSF3 expression was significantly lower (10.4%). High expression of PSF3 was associated with more advanced pathologic T stage (P = .000), lymphatic invasion (P = .001), and poor clinical outcomes such as shorter relapse-free survival (P = .000) and overall survival (P = .001). When we compared the immunostaining of PSF3 and Ki-67, the proportions of PSF3-positive cells in tumor epithelial cells were comparable to those of Ki-67-positive cells. However, PSF3-positive cells were selectively found in tumor cells, whereas Ki-67-positive cells were also found in tumor stromal cells. These results demonstrated that PSF3 immunostaining was valuable as a histopathologic marker for differential diagnosis between atypical hyperplasia and ECs, for tumor histologic grading, and for determining a patient's prognosis. PSF3 may play a crucial role in tumor progression in EC.

GINS2 promotes cell proliferation and inhibits cell apoptosis in thyroid cancer by regulating CITED2 and LOXL2

To explore the mechanisms of GINS2 on cell proliferation and apoptosis in thyroid cancer (TC) cells. Expressions of GINS2 were inhibited in K1 and SW579 cells using gene interference technology. The abilities of proliferation and apoptosis, and cell cycle were determined by MTT assay and flow cytometric assay. The downstream molecules of GINS2 were searched by microarray and bioinformatics and validated by qRT-PCR and western blotting. In the in vivo study, the tumor growth was compared and the whole-body fluorescent imaging was analyzed. After GINS2 was interfered, cell proliferation was significantly inhibited (P < 0.01) and apoptosis rate increased (P < 0.01) in both K1 and SW579 cells. Cell cycle changed significantly in K1 cells, but not in SW579 cells. With bioinformatics upstream analysis, TGF-β1 was found as the most significantly upstream regulator. Expressions of TGF-β1 and its downstream target molecules CITED2 and LOXL2 were validated and found downregulated significantly in mRNA and protein levels (P < 0.05). The results of the nude mouse xenograft assay suggested that the volume and weight of tumor in ones infected with shGINS2 were statistically smaller than controls (P < 0.05). GINS2 plays an important role in cell proliferation and apoptosis of thyroid cancer by regulating the expressions of CITED2 and LOXL2, which may be a potential biomarker for diagnosis or prognosis and a drug target for therapy.

Augmented expression of Ki-67 is correlated with clinicopathological characteristics and prognosis for lung cancer patients: an up-dated systematic review and meta-analysis with 108 studies and 14,732 patients

Background

Lung cancer ranks as the leading cause of cancer-related deaths worldwide and we performed this meta-analysis to investigate eligible studies and determine the prognostic effect of Ki-67.

Methods

In total, 108 studies in 95 articles with 14,732 patients were found to be eligible, of which 96 studies reported on overall survival (OS) and 19 studies reported on disease-free survival (DFS) with relation to Ki-67 expression in lung cancer patients.

Results

The pooled hazard ratio (HR) indicated that a high Ki-67 level could be a valuable prognostic factor for lung cancer (HR = 1.122 for OS, P < 0.001 and HR = 1.894 for DFS, P < 0.001). Subsequently, the results revealed that a high Ki-67 level was significantly associated with clinical parameters of lung cancer including age (odd ratio, OR = 1.246 for older patients, P = 0.018), gender (OR = 1.874 for males, P < 0.001) and smoking status (OR = 3.087 for smokers, P < 0.001). Additionally, significant positive correlations were found between Ki-67 overexpression and poorer differentiation (OR = 1.993, P = 0.003), larger tumor size (OR = 1.436, P = 0.003), and higher pathologic stages (OR = 1.867 for III-IV, P < 0.001). Furthermore, high expression of Ki-67 was found to be a valuable predictive factor for lymph node metastasis positive (OR = 1.653, P < 0.001) and advanced TNM stages (OR = 1.497 for stage III-IV, P = 0.024). Finally, no publication bias was detected in any of the analyses.

Conclusions

This study highlights that the high expression of Ki-67 is clinically relevant in terms of the prognostic and clinicopathological characteristics for lung cancer. Nevertheless, more prospective well-designed studies are warranted to validate these findings.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0843-7) contains supplementary material, which is available to authorized users.

Dysfunction of Sister Chromatids Separation Promotes Progression of Hepatocellular Carcinoma According to Analysis of Gene Expression Profiling

Despite studying the various molecular mechanisms of hepatocellular carcinoma (HCC), effective drugs and biomarkers in HCC therapy are still scarce. The present study was designed to investigate dysregulated pathways, novel biomarkers and therapeutic targets for HCC. The gene expression dataset of GSE14520, which included 362 tumor and their paired non-tumor tissues of HCC, was extracted for processing by the Robust multi-array average (RMA) algorithm in the R environment. SAM methods were leveraged to identify differentially expressed genes (DEGs). Functional analysis of DEGs was performed using DAVID. The GeneMania and Cytohubba were used to construct the PPI network. To avoid individual bias, GSEA and survival analysis were employed to verify the results. The results of these analyses indicated that separation of sister chromatids was the most aberrant phase in the progression of HCC, and the most frequently involved genes, EZH2, GINS1, TPX2, CENPF, and BUB1B, require further study to be used as drug targets or biomarkers in diagnosis and treatment of HCC.

The Human Replicative Helicase, the CMG Complex, as a Target for Anti-cancer Therapy

DNA helicases unwind or rearrange duplex DNA during replication, recombination and repair. Helicases of many pathogenic organisms such as viruses, bacteria, and protozoa have been studied as potential therapeutic targets to treat infectious diseases, and human DNA helicases as potential targets for anti-cancer therapy. DNA replication machineries perform essential tasks duplicating genome in every cell cycle, and one of the important functions of these machineries are played by DNA helicases. Replicative helicases are usually multi-subunit protein complexes, and the minimal complex active as eukaryotic replicative helicase is composed of 11 subunits, requiring a functional assembly of two subcomplexes and one protein. The hetero-hexameric MCM2-7 helicase is activated by forming a complex with Cdc45 and the hetero-tetrameric GINS complex; the Cdc45-Mcm2-7-GINS (CMG) complex. The CMG complex can be a potential target for a treatment of cancer and the feasibility of this replicative helicase as a therapeutic target has been tested recently. Several different strategies have been implemented and are under active investigations to interfere with helicase activity of the CMG complex. This review focuses on the molecular function of the CMG helicase during DNA replication and its relevance to cancers based on data published in the literature. In addition, current efforts made to identify small molecules inhibiting the CMG helicase to develop anti-cancer therapeutic strategies were summarized, with new perspectives to advance the discovery of the CMG-targeting drugs.

Current and Prospective Protein Biomarkers of Lung Cancer

Lung cancer is a malignant lung tumor with various histological variants that arise from different cell types, such as bronchial epithelium, bronchioles, alveoli, or bronchial mucous glands. The clinical course and treatment efficacy of lung cancer depends on the histological variant of the tumor. Therefore, accurate identification of the histological type of cancer and respective protein biomarkers is crucial for adequate therapy. Due to the great diversity in the molecular-biological features of lung cancer histological types, detection is impossible without knowledge of the nature and origin of malignant cells, which release certain protein biomarkers into the bloodstream. To date, different panels of biomarkers are used for screening. Unfortunately, a uniform serum biomarker composition capable of distinguishing lung cancer types is yet to be discovered. As such, histological analyses of tumor biopsies and immunohistochemistry are the most frequently used methods for establishing correct diagnoses. Here, we discuss the recent advances in conventional and prospective aptamer based strategies for biomarker discovery. Aptamers like artificial antibodies can serve as molecular recognition elements for isolation detection and search of novel tumor-associated markers. Here we will describe how these small synthetic single stranded oligonucleotides can be used for lung cancer biomarker discovery and utilized for accurate diagnosis and targeted therapy. Furthermore, we describe the most frequently used in-clinic and novel lung cancer biomarkers, which suggest to have the ability of differentiating between histological types of lung cancer and defining metastasis rate.

INTEGRATIVE ANALYSIS FOR LUNG ADENOCARCINOMA PREDICTS MORPHOLOGICAL FEATURES ASSOCIATED WITH GENETIC VARIATIONS

Lung cancer is one of the most deadly cancers and lung adenocarcinoma (LUAD) is the most common histological type of lung cancer. However, LUAD is highly heterogeneous due to genetic difference as well as phenotypic differences such as cellular and tissue morphology. In this paper, we systematically examine the relationships between histological features and gene transcription. Specifically, we calculated 283 morphological features from histology images for 201 LUAD patients from TCGA project and identified the morphological feature with strong correlation with patient outcome. We then modeled the morphology feature using multiple co-expressed gene clusters using Lasso-regression. Many of the gene clusters are highly associated with genetic variations, specifically DNA copy number variations, implying that genetic variations play important roles in the development cancer morphology. As far as we know, our finding is the first to directly link the genetic variations and functional genomics to LUAD histology. These observations will lead to new insight on lung cancer development and potential new integrative biomarkers for prediction patient prognosis and response to treatments.

Significant role of Psf3 expression in non-small-cell lung cancer

The GINS complex associates with cell division cycle (Cdc) protein 45 and mini‐chromosome maintenance (Mcm) proteins 2–7 to form the Cdc45–Mcm–GINS (CMG) complex, which is essential for DNA duplication. One member of the GINS complex is Psf3. We previously found that increased Psf3 expression was strongly associated with poor survival in lung adenocarcinoma. Here, we investigated the role of Psf3 expression in non‐small‐cell lung cancer (NSCLC). We verified Psf3 expression in human NSCLC tissues (180 patients) and cell lines. Immunohistochemical analysis revealed that the overexpression of Psf3 was significantly associated with vessel invasion (P = 0.016), lymphatic invasion (P = 0.002), and pleural invasion (P = 0.036). The overall survival rate in patients with Psf3 overexpression was significantly lower than that in patients without Psf3 overexpression (P = 0.006). Multivariate survival analysis revealed Psf3 expression to be an independent risk factor for an unfavorable outcome (P = 0.049). A proximal ligation assay showed interactions between Psf3 and other CMG components (such as Mcm2 and Cdc45) in both NSCLC specimens and cell lines, indicating that Psf3 acted as the CMG complex, which could lead to excessive proliferation. Knockdown of Psf3 inhibited the proliferation of both cell lines by delaying the S phase, which revealed that Psf3 played an important role in cancer proliferation. Thus, Psf3 acted as the CMG complex, promoting excessive proliferation. These results suggest that Psf3 inhibition might be a therapeutic target for NSCLC with Psf3 overexpression.

Partner of Sld five 3: a potential prognostic biomarker for colorectal cancer

BACKGROUND

Partner of Sld five 3 (PSF3) is a member of the evolutionarily conserved heterotetrameric complex "Go-Ichi-Ni-San" (GINS), which consists of SLD5, PSF1, PSF2, and PSF3. Previous studies have suggested that some GINS complex members are upregulated in cancer, but the status of PSF3 expression in colorectal cancer has not been investigated.

METHODS

We investigated the status of PSF3 expression in 137 consecutive resected colorectal caners by quantitative reverse-transcription polymerase chain reaction. Univariable and multivariable Cox regression analyses were performed to assess independent prognostic factors for overall survival in colorectal cancer.

RESULTS

In 137 restected colorectal cancer samples, median messenger RNA (mRNA) expression levels of PSF3 were significantly higher in tumor tissues (1.35 × 10(-3), range 2.88 × 10(-4) to 3.16 × 10(-2)) than in adjacent normal tissues (2.94 × 10(-4), range 5.48 × 10(-5) to 1.27 × 10(-3)) (P < 0.05). Moreover, high expression of PSF3 in tumor tissues was associated with shorter disease-free survival and overall survival. When analyzed with a Cox regression model, the PSF3 expression was an independent prognostic factor for overall survival. In addition, in patients with early stage (stage I and II) colorectal cancer, the overall survival rate of the high PSF3 expression group was significantly lower than that of the low PSF3 expression group (P < 0.001).

CONCLUSIONS

The PSF3 expression plays an important role in the progression of colorectal cancer and acts as a factor significantly affecting the prognosis of patients.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_217.

Knockdown of PSF1 expression inhibits cell proliferation in lung cancer cells in vitro

Partner of sld five 1 (PSF1) is a member of the heterotetrameric complex termed GINS. Previous studies have shown that PSF1 is unregulated in several cancer and associated with tumor malignant characters. However, the effects of PSF1 in lung cancer are still unclear. The goal of this study was to investigate the effects of PSF1 on the proliferation capacities of lung cancer. To start with, expression of PSF1 in 22 human lung cancer samples and adjacent non-tumor samples were detected by real-time RT-PCR and Western blotting. Our results showed that PSF1 was overexpressed in lung cancer samples compared to adjacent non-tumor samples. To achieve better insights of PSF1 functions in lung cancer cells, we used PSF1-specific small interfering RNA (siRNA) successfully inhibit the expression of PSF1 in messenger RNA (mRNA) and protein levels. In addition, we used lung cancer cell lines with different p53 gene background (p53 null and p53 wild-type). The results showed that knockdown of PSF1 inhibited cell proliferation and caused cell cycle arrest of lung cancer cells in a p53-independent manner. Our data indicated that PSF1 is functionally involved in lung cancer cell proliferation and is a potential target for lung cancer therapy.

Proper functioning of the GINS complex is important for the fidelity of DNA replication in yeast

The role of replicative DNA polymerases in ensuring genome stability is intensively studied, but the role of other components of the replisome is still not fully understood. One of such component is the GINS complex (comprising the Psf1, Psf2, Psf3 and Sld5 subunits), which participates in both initiation and elongation of DNA replication. Until now, the understanding of the physiological role of GINS mostly originated from biochemical studies. In this article, we present genetic evidence for an essential role of GINS in the maintenance of replication fidelity in Saccharomyces cerevisiae. In our studies we employed the psf1-1 allele (Takayama et al., 2003) and a novel psf1-100 allele isolated in our laboratory. Analysis of the levels and specificity of mutations in the psf1 strains indicates that the destabilization of the GINS complex or its impaired interaction with DNA polymerase epsilon increases the level of spontaneous mutagenesis and the participation of the error-prone DNA polymerase zeta. Additionally, a synergistic mutator effect was found for the defects in Psf1p and in the proofreading activity of Pol epsilon, suggesting that proper functioning of GINS is crucial for facilitating error-free processing of terminal mismatches created by Pol epsilon.

Sirt1 is a tumor promoter in lung adenocarcinoma

Sirtuin 1 (Sirt1) is a nicotinamide adenine dinucleotide-dependent class III histone deacetylase. It reportedly can repress cellular apoptosis and senescence to affect DNA repair, stress response and aging. Notably, previous data have indicated that Sirt1 is both a tumor promoter and a tumor suppressor in tumorigenesis. However, Sirt1 expression in primary lung adenocarcinoma remains unknown. Immunohistochemical staining was performed to investigate Sirt1 expression in cancer cells in 125 consecutive resected cases of primary lung adenocarcinoma. Sirt1 expression was found to be increased in 26 (20.8%) of the 125 cases, which correlated significantly with five clinicopathological factors: Ki67 index, hypoxia-inducible factor 1 (HIF1) molecule expression, tumor-node-metastasis (TNM) classification, pulmonary vein invasion and lymphatic duct invasion. In the Sirt1-positive expression group, Sirt1 expression correlated with a higher Ki67 index and higher TNM classification, particularly for lymph node invasion and metastasis, and with a higher number of pulmonary vein invasion and lymphatic duct invasion. Additionally, a negative correlation was identified between HIF1-positive expression and Sirt1-negative expression. These results indicate that Sirt1 overexpression plays a promotional role in tumorigenesis and is closely associated with invasion and metastasis and, thus, it may be associated with prognosis.