Predictive value of APE1, BRCA1, ERCC1 and TUBB3 expression in patients with advanced non-small cell lung cancer (NSCLC) receiving first-line platinum–paclitaxel chemotherapy

Unraveling the role of deubiquitinating enzymes on cisplatin resistance in several cancers

The use of platinum-based drugs in cancer treatment is one of the most common methods in chemotherapy. Especially, cisplatin induces cell death by interrupting DNA synthesis by binding to the DNA bases, thereby leading to the apoptosis via multiple pathways. However, the major hurdle in chemotherapy is drug resistance. To overcome drug resistance, the ubiquitin-proteasome system (UPS) has emerged as a potential therapeutic target. The UPS is a pivotal signaling pathway that regulates the majority of cellular proteins by attaching ubiquitin to substrates, leading to proteasomal degradation. Conversely, deubiquitinating enzymes (DUBs) remove tagged ubiquitin from the substrate and inhibit degradation, thereby maintaining proteostasis. Recently, studies have been conducted to identify the substrates of DUBs and investigated the cellular mechanisms, and now the development of therapeutics using DUB inhibitors is in clinical trials. However, the mechanism of the DUB response to cisplatin remains still unclear. In this review, we summarize the research reported on the function of DUBs responding to cisplatin.

Predictive Value of Excision Repair Cross Complementation Group 1 (ERCC1) by Immunohistochemistry for Determining Neoadjuvant Chemotherapy Response in Triple-Negative Breast Cancers

Introduction: Triple-negative breast cancers (TNBCs) constitute a significant proportion of breast cancers in Pakistan. Owing to the lack of expression of hormone (estrogen/progesterone) receptor and human epidermal growth factor receptor 2 (HER2neu), treatment options for TNBCs are limited. Therefore, it is important to identify markers that predict response to chemotherapy in these patients. Previous studies have demonstrated that the excision repair cross complementation group 1 (ERCC1) protein can successfully augur the response to chemotherapy in cancer; however, data related to TNBCs, particularly in Pakistan, are limited. Therefore, in this study, we evaluated the role of ERCC1 in predicting the response to neoadjuvant chemotherapy in patients with TNBCs. Methods: This cross-sectional study was conducted at the Liaquat National Hospital, Histopathology Department, between January 2019 and June 2023. A total of 132 biopsy-proven cases of breast cancer that were negative for estrogen receptor (ER), progesterone receptor (PR), and HER/2neu and were administered neoadjuvant chemotherapy before surgery were included in the study. ERCC1 immunohistochemical (IHC) staining was performed on prechemotherapy needle biopsies. The results were scored semiquantitatively by assessing the average intensity on a scale of 0-3 (0, no staining; 1, weak nuclear staining; 2, intermediate nuclear staining; and 3, strong nuclear staining) and the proportion of tumor cells showing positive nuclear staining. The intensity and proportion scores were then multiplied to give a score that was divided by 100 to give an overall score, and scores equal to or higher than 1.0 were considered positive. Neoadjuvant chemotherapy response was categorized as pathological complete response (pCR) when no residual invasive breast carcinoma was found on the postneoadjuvant chemotherapy excision specimen and as pathological partial response (pPR) when residual cancer cells were present in admixed chemotherapy-related changes. The residual cancer burden (RCB) was calculated using the MD Anderson RCB calculator. The association between ERCC1 expression and the chemotherapy response/RCB class was determined. Results: We found that 90.9% (n = 120) of TNBC cases expressed ERCC1, whereas pCR was noted in 24 (18.2%) cases. A significant association was observed between ERCC1 expression and pCR. Cases with negative ERCC1 expression had a significantly higher frequency of pCR (66.7%) than those with positive ERCC1 expression (13.3%). Additionally, the ERCC1-positive group showed a higher frequency of RCB classes II (36.7%) and III (43.3%) than the ERCC1-negative group (RCB II: 25%; RCB III: 0%). Moreover, positive ERCC1 expression was associated with higher nodal (N) stage. Conclusion: In this study, we established the role of negative ERCC1 expression in predicting the response to chemotherapy in neoadjuvant TNBC. Therefore, ERCC1 can be used as a predictive marker to stratify patients who will benefit from neoadjuvant therapy. Moreover, we also noted an association between ERCC1 expression and nodal metastasis; however, more large-scale studies are needed to establish its role as a prognostic biomarker in TNBC.

SNPs in 3'UTR miRNA Target Sequences Associated with Individual Drug Susceptibility

The complementary interaction of microRNAs (miRNAs) with their binding sites in the 3'untranslated regions (3'UTRs) of target gene mRNAs represses translation, playing a leading role in gene expression control. MiRNA recognition elements (MREs) in the 3'UTRs of genes often contain single nucleotide polymorphisms (SNPs), which can change the binding affinity for target miRNAs leading to dysregulated gene expression. Accumulated data suggest that these SNPs can be associated with various human pathologies (cancer, diabetes, neuropsychiatric disorders, and cardiovascular diseases) by disturbing the interaction of miRNAs with their MREs located in mRNA 3'UTRs. Numerous data show the role of SNPs in 3'UTR MREs in individual drug susceptibility and drug resistance mechanisms. In this review, we brief the data on such SNPs focusing on the most rigorously proven cases. Some SNPs belong to conventional genes from the drug-metabolizing system (in particular, the genes coding for cytochromes P450 (CYP 450), phase II enzymes (SULT1A1 and UGT1A), and ABCB3 transporter and their expression regulators (PXR and GATA4)). Other examples of SNPs are related to the genes involved in DNA repair, RNA editing, and specific drug metabolisms. We discuss the gene-by-gene studies and genome-wide approaches utilized or potentially utilizable to detect the MRE SNPs associated with individual response to drugs.

ERCC1 is a potential biomarker for predicting prognosis, immunotherapy, chemotherapy efficacy, and expression validation in HER2 over-expressing breast cancer

Objective

To investigate the relationship between Excision repair cross-complementation 1 (ERCC1) expression, clinicopathological features, and breast cancer prognosis in patients treated with trastuzumab. Further, we aim to explore the immune status of ERCC1 in breast cancer.

Methods

The data were retrieved from publicly available databases like the Cancer Genome Atlas, Therapeutically Applicable Research to Generate Effective Treatments, and the Genotype-Tissue Expression. The data was used to perform differential expression analyses between tumor and normal tissues in pan-cancers, immune-related analysis, homologous recombination deficiency (HRD), tumor mutation burden, and microsatellite instability. A total of 210 patients with HER2 over-expressing breast cancer from the Fourth Hospital of Hebei Medical University between January 2013 to December 2015 were enrolled in the study. Ten adjacent normal tissues were used to study the expression pattern of ERCC1 in normal tissues. Immunohistochemistry was performed to study ERCC1 expression and immune cell infiltration in different status of ERCC1 expression. Further, the correlation between ERCC1 expression, immune cell infiltration clinicopathological features, and the prognosis of patients with breast cancer was analyzed.

Results

The immune analysis revealed a significant correlation between CD8+ T cell, CD4+ T cell, T helper cell, macrophages, mast cells, and ERCC1 expression. Spearman analysis show that ERCC1 expression is related to macrophages and T cells. A close correlation was observed between increased ERCC1 expression and high tumor immune dysfunction and exclusion (TIDE) score as well as HRD. The results revealed a significant correlation among ERCC1, chemotherapy and estrogen receptor (ER; P < 0.05) expression. Univariate survival analysis revealed a significant correlation (P < 0.05) between that ERCC1 and ER expression, blood vessel invasion, and disease-free survival (DFS). ERCC1 and ER expression, tumor size, blood vessel invasion, pathological type, and lymph node metastases significantly correlated (P < 0.05) with overall survival in patients. Multivariate regression analysis revealed that ERCC1 expression and chemotherapy were independent factors that influence DFS. ERCC1 expression and vascular tumor thrombus were independent influencing factors that influence OS.

Conclusion

A correlation was observed between high ERCC1 expression and poor patient prognosis. High ERCC1 expression also influences the efficacy of immunotherapy and chemotherapy.

ERCC1 Overexpression Increases Radioresistance in Colorectal Cancer Cells

Preoperative concurrent chemoradiotherapy (CCRT) is a standard treatment for locally advanced rectal cancer patients, but 20-30% do not benefit from the desired therapeutic effects. Previous reports indicate that high levels of ERCC1 reduce the effectiveness of cisplatin-based CCRT; however, it remains unclear as to whether ERCC1 overexpression increases radiation resistance. To clarify the correlation between ERCC1 levels and radiation (RT) resistance, we established two cell lines (HCT116-Tet-on and COLO205-Tet-on), induced them to overexpress ERCC1, detected cell survival following exposure to radiation, established HCT116-Tet-on and COLO205-Tet-on heterotopic cancer animal models, and detected tumor volume following exposure to radiation. We found that ERCC1 overexpression increased radiation resistance. After regulating ERCC1 levels and radiation exposure to verify the correlation, we noted that increased radiation resistance was dependent on ERCC1 upregulation in both cell lines. For further verification, we exposed HCT116-Tet-on and COLO205-Tet-on heterotopic cancer animal models to radiation and observed that ERCC1 overexpression increased colorectal cancer tumor radioresistance in both. Combined, our results suggest that ERCC1 overexpression may serve as a suitable CCRT prognostic marker for colorectal cancer patients.

Upregulation of the Long Noncoding RNA CASC10 Promotes Cisplatin Resistance in High-Grade Serous Ovarian Cancer

Despite initial responses to first-line treatment with platinum and taxane-based combination chemotherapy, most high-grade serous ovarian carcinoma (HGSOC) patients will relapse and eventually develop a cisplatin-resistant fatal disease. Due to the lethality of this disease, there is an urgent need to develop improved targeted therapies against HGSOC. Herein, we identified CASC10, a long noncoding RNA upregulated in cisplatin-resistant ovarian cancer cells and ovarian cancer patients. We performed RNA sequencing (RNA-seq) in total RNA isolated from the HGSOC cell lines OVCAR3 and OV-90 and their cisplatin-resistant counterparts. Thousands of RNA transcripts were differentially abundant in cisplatin-sensitive vs. cisplatin-resistant HGSOC cells. Further data filtering unveiled CASC10 as one of the top RNA transcripts significantly increased in cisplatin-resistant compared with cisplatin-sensitive cells. Thus, we focused our studies on CASC10, a gene not previously studied in ovarian cancer. SiRNA-mediated CASC10 knockdown significantly reduced cell proliferation and invasion; and sensitized cells to cisplatin treatment. SiRNA-mediated CASC10 knockdown also induced apoptosis, cell cycle arrest, and altered the expression of several CASC10 downstream effectors. Multiple injections of liposomal CASC10-siRNA reduced tumor growth and metastasis in an ovarian cancer mouse model. Our results demonstrated that CASC10 levels mediate the susceptibility of HGSOC cells to cisplatin treatment. Thus, combining siRNA-mediated CASC10 knockdown with cisplatin may represent a plausible therapeutic strategy against HGSOC.

Randomised phase II trial of weekly ixabepilone ± biweekly bevacizumab for platinum-resistant or refractory ovarian/fallopian tube/primary peritoneal cancer

BACKGROUND

This multi-center RP2 study assessed activity/safety of ixabepilone + bevacizumab compared to ixabepilone in platinum-resistant/refractory ovarian/fallopian tube/primary peritoneal cancer. Additional objectives were to examine the role of prior bevacizumab and taxanes, and explore class III-ß-tubulin (TUBB3) as a predictive biomarker.

METHODS

Participants were randomised to receive ixabepilone 20 mg/m2 days 1, 8, 15 with (IXA + BEV) or without (IXA) bevacizumab 10 mg/kg days 1, 15 every 28 days. Patients were stratified by prior BEV. The primary endpoint was PFS. OS, safety, and ORR served as secondary endpoints.

RESULTS

Among 76 evaluable patients who received IXA + BEV (n = 39) compared to IXA (n = 37), the ORR was 33% (n = 13) versus 8% (n = 3)(P = 0.004), durable at 6 months in 37% (n = 14) and 3% (n = 1) (P < 0.001). BEV significantly improved PFS (median:5.5 vs 2.2 months, HR = 0.33, 95%CI 0.19-0.55, P < 0.001) and OS (median:10.0 vs 6.0 months, HR = 0.52, 95%CI 0.31-0.87, P = 0.006). Both regimens were well-tolerated. TUBB3 expression did not predict response. Subgroup analyses revealed minimal effect of prior BEV or taxane resistant/refractory status on response to IXA + BEV.

CONCLUSIONS

IXA + BEV is a well-tolerated, effective combination for platinum/taxane-resistant ovarian cancer that extends PFS and likely OS relative to IXA monotherapy. Prior receipt of BEV should not preclude the use of IXA + BEV. TUBB3 is not a predictive biomarker.

CLINICAL TRIAL REGISTRATION

NCT3093155.

FV-429 enhances the efficacy of paclitaxel in NSCLC by reprogramming HIF-1α-modulated FattyAcid metabolism

Solid tumors often exhibit hypoxia in their centers, which has been associated with a marked reduction in the sensitivity of the tumor cells to anti-tumor and chemotherapeutic interventions. Here, we found that the occurrence and progress of hypoxic insensitivity to paclitaxel in non-small cell lung cancer (NSCLC) are closely associated with the HIF-1α pathway. The HIF-1α protein upregulated the expression of adipose differentiation-related protein (ADRP), fatty acid synthase (FASN), and sterol regulatory element binding protein 1(SREBP1), while simultaneously downregulating carnitine palmitoyltransferase 1 (CPT1), thereby leading to a more pronounced uptake of lipids and reduced oxidation of fatty acids. Diminished levels of fatty acids led to reduced Wnt pathway activation and β-catenin nuclear translocation, leading to G2/M cell cycle arrest. In this study, FV-429, a derivative of the natural flavonoid wogonin, reprogrammed metabolism of cancer cells and decreased fatty acid levels. Moreover, paclitaxel-induced G2/M phase arrest in hypoxia-resistant NSCLC was hampered but FV-429 improved the sensitivity of these cancer cells to paclitaxel. FV-429 activated and modulated fatty acid metabolism in NSCLC cells, significantly reduced levels of fatty acids within cells and increased the oxidation of these fatty acids. The results of our study demonstrated that FV-429 could reshape fatty acid metabolism in hypoxia-induced paclitaxel-resistant NSCLC and enhance the sensitivity of NSCLC cells to paclitaxel through G2/M phase arrest deterioration, by inactivating the Wnt pathway, and suggested the possibility of using FV-429 as a promising candidate therapeutic agent for advanced NSCLC.

APE1 may influence CD4+ naïve T cells on recurrence free survival in early stage NSCLC

Background

It was demonstrated that multifunctional protein APE1 (Apurinic/apyrimidinic endonuclease 1) is closely related to tumor immune microenvironment in a number of investigations, Meanwhile, the abundance of tumor infiltrating lymphocytes (TILs) has been shown as a prognosis indicator in some researches. However, it remains unclear whether APE1 is involved in the process of TILs affecting the prognosis of patients. To this end, we investigated the associations between APE1 and TILs in non-small cell lung cancer (NSCLC) and explored whether APE1 would influence the associations of CD4⁺ T cells infiltration with the prognosis of patients.

Methods

Genome-wide expression datasets were obtained from the Gene Expression Omnibus (GEO) public database under accession number GSE68465, GSE30219, GSE31210 and GSE50081. MCPcounter and CIBERSORT analysis was conducted to evaluate the abundance of TILs in 1006 NSCLC patients of GEO database. Spearman correlation tests were used to evaluate correlations between abundance of various TILs and APE1 expression. RFS (recurrence free survival) was estimated using the Kaplan–Meier method and the Cox proportional-hazards model. The expression level of APE1 and tumor-infiltrating CD4⁺ T cells was evaluated by immunohistochemistry (IHC).

Results

The results showed that the abundance of CD4⁺ naïve T cells was negatively associated with the APE1 expression. CD4⁺ naïve T cells infiltration was a favorable prognostic factor for RFS, however, there was no effect of CD4⁺ T cells infiltration on RFS in patients with high APE1 expression. Subsequently, it was further confirmed that CD4⁺ T cells infiltration was negatively associated with the APE1 expression level in 108 NSCLC tissue samples; high CD4⁺ T cells infiltration was associated with longer RFS in low APE1 expression group but not in APE1 high expression group.

Conclusion

These results suggested that APE1 may affect the relationship between CD4⁺ T cells infiltration and prognosis in NSCLC. This study provides new insights into predictors of outcome in patients with NSCLC, and suggests that combining immunotherapy and APE1-targeted therapy may be a promising treatment for NSCLC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-07950-1.

Mechanisms of Taxane Resistance

The taxane family of chemotherapy drugs has been used to treat a variety of mostly epithelial-derived tumors and remain the first-line treatment for some cancers. Despite the improved survival time and reduction of tumor size observed in some patients, many have no response to the drugs or develop resistance over time. Taxane resistance is multi-faceted and involves multiple pathways in proliferation, apoptosis, metabolism, and the transport of foreign substances. In this review, we dive deeper into hypothesized resistance mechanisms from research during the last decade, with a focus on the cancer types that use taxanes as first-line treatment but frequently develop resistance to them. Furthermore, we will discuss current clinical inhibitors and those yet to be approved that target key pathways or proteins and aim to reverse resistance in combination with taxanes or individually. Lastly, we will highlight taxane response biomarkers, specific genes with monitored expression and correlated with response to taxanes, mentioning those currently being used and those that should be adopted. The future directions of taxanes involve more personalized approaches to treatment by tailoring drug-inhibitor combinations or alternatives depending on levels of resistance biomarkers. We hope that this review will identify gaps in knowledge surrounding taxane resistance that future research or clinical trials can overcome.

ERCC1, PARP-1, and AQP1 as predictive biomarkers in colon cancer patients receiving adjuvant chemotherapy

BACKGROUND

The recognition of high-risk colon cancer patients prone to chemoresistant and recurrent disease is a challenge.

OBJECTIVES

We aimed to assess the immunohistochemical expression of ERCC1, PARP-1, and AQP1 in 60 cases of stage II and III colon cancer who underwent curative resection and adjuvant chemotherapy. Their predictive role of tumor progression and disease-free survival (DFS) was analyzed.

METHODS

The immunohistochemical expression of ERCC1, PARP-1, and AQP1 in 60 cases of stage II and III colon cancer who underwent curative resection and adjuvant chemotherapy was studied. The collected data on the overall survival (OS), disease-free survival (DFS), and the response to the chemotherapy were analyzed.

RESULTS

Positive nuclear ERCC1 expression was identified in 58.3% of the patients, ERCC1 expression was significantly associated with left-sided tumors (P< 0.01). Moreover, its expression was significantly associated with the aggressive tumor characteristics including high grade, lymph node metastasis and advanced tumor stage (P< 0.001 for each). High nuclear PARP-1 expression was observed in 63.3% of the cases, and its expression was significantly associated with tumor grade and lymph node metastasis (P= 0.003 for each). Positive membranous AQP1 expression was identified in 41.7% of patients, and it was associated with high grade, lymph node metastasis and advanced tumor stage (P< 0.001 for each). During the follow-up period, 23 patients (38.3%) exhibited a tumor progression; this was significantly associated with positive ERCC1, high PARP-1, and negative AQP1 expression. Statistics of the survival data revealed that shorter DFS was significantly associated with positive ERCC1, high PARP-1, and positive AQP1 expression (P= 0.005, 0.016, 0.002, respectively).

CONCLUSIONS

ERCC1, PARP1, and AQP1 are adverse prognostic biomarkers in stage II-III colon cancer. Moreover, adjuvant chemotherapy may not be beneficial for patients with positive ERCC1, high PARP1, and AQP1-negative tumors. Therefore, we recommend that ERCC1, PARP-1, and AQP1 should be assessed during the selection of the treatment strategy for stage II-III colon cancer patients.

Association of high TUBB3 with resistance to adjuvant docetaxel-based chemotherapy in gastric cancer: translational study of ITACA-S

BACKGROUND

No predictive markers for chemotherapy activity have been validated in gastric cancer (GC). The potential value of class III β-tubulin (TUBB3) as biomarker for prognosis and resistance to taxane-based therapy was reported.

METHODS

We analyzed GC samples of patients enrolled in the Intergroup Trial of Adjuvant Chemotherapy in Adenocarcinoma of the Stomach (ITACA-S), a randomized adjuvant study comparing 5-fluorouracil/leucovorin (5-FU/LV) and docetaxel-based sequential chemotherapy. TUBB3 was quantitated by selected reaction monitoring mass spectrometry and patients were stratified using a threshold of 750 attomoles per microgram (amol/µg). Cox proportional modeling and Kaplan-Meier survival analysis were used to assess the impact of TUBB3 expression on overall survival (OS) and disease-free survival.

RESULTS

Patients with TUBB3 protein levels >750 and <750 amol/µg were 21.9% and 78.1%, respectively, and were well-balanced between treatment arms. TUBB3 protein levels were not prognostic. Whereas no survival differences according to the 2 arms were observed in the subgroup with low TUBB3 expression (5-year OS 47% vs 40%; p = 0.44), patients with high TUBB3 had a clinically meaningful poorer OS when receiving docetaxel-based versus 5-FU/LV chemotherapy (5-year OS 31% vs 54%; p = 0.09), with a statistically significant interaction between TUBB3 and treatment (p = 0.049).

CONCLUSIONS

The quantification of TUBB3 might be considered as a negative predictive biomarker of benefit from taxane-based therapy in GC. Studies are needed to evaluate its role in the neoadjuvant setting.

A randomized, double-blind, placebo-controlled study of B-cell lymphoma 2 homology 3 mimetic gossypol combined with docetaxel and cisplatin for advanced non-small cell lung cancer with high expression of apurinic/apyrimidinic endonuclease 1

Background Overexpression of apurinic/apyrimidinic endonuclease 1 (APE1) is an important cause of poor chemotherapeutic efficacy in advanced non-small cell lung cancer (NSCLC) patients. Gossypol, a new inhibitor of APE1, in combination with docetaxel and cisplatin is believed to improve the efficacy of chemotherapy for advanced NSCLC with high APE1 expression. Methods Sixty-two patients were randomly assigned to two groups. Thirty-one patients in the experimental group received 75 mg/m² docetaxel and 75 mg/m² cisplatin on day 1 with gossypol administered at 20 mg once daily on days 1 to 14 every 21 days. The control group received placebo with the same docetaxel and cisplatin regimen. The primary endpoint was progression-free survival (PFS); secondary endpoints included overall survival (OS), response rate, and toxicity. Results There were no significant differences in PFS and OS between the experimental group and the control group. The median PFS (mPFS) in the experimental and control groups was 7.43 and 4.9 months, respectively (HR = 0.54; p = 0.06), and the median OS (mOS) was 18.37 and 14.7 months, respectively (HR = 0.68; p = 0.27). No significant differences in response rate and serious adverse events were found between the groups. Conclusion The experimental group had a better mPFS and mOS than did the control group, though no significant difference was observed. Because the regimen of gossypol combined with docetaxel and cisplatin was well tolerated, future studies with larger sample sizes should be performed.

Diagnostic and Prognostic Potential of Biomarkers CYFRA 21.1, ERCC1, p53, FGFR3 and TATI in Bladder Cancers

The high occurrence of bladder cancer and its tendency to recur in combination with a lifelong surveillance make the treatment of superficial bladder cancer one of the most expensive and time-consuming. Moreover, carcinoma in situ often leads to muscle invasion with an unfavorable prognosis. Currently, invasive methods including cystoscopy and cytology remain a gold standard. The aim of this study was to explore urine-based biomarkers to find the one with the best specificity and sensitivity, which would allow optimizing the treatment plan. In this review, we sum up the current knowledge about Cytokeratin fragments (CYFRA 21.1), Excision Repair Cross-Complementation 1 (ERCC1), Tumour Protein p53 (Tp53), Fibroblast Growth Factor Receptor 3 (FGFR3), Tumor-Associated Trypsin Inhibitor (TATI) and their potential applications in clinical practice.

Genetic variants in RPA1 associated with the response to oxaliplatin-based chemotherapy in colorectal cancer

BACKGROUND

Oxaliplatin (L-OHP) is a commonly used first-line chemotherapy for colorectal cancer. Genetic variants in nucleotide excision repair (NER) pathway genes may alter genomic integrity and the efficacy of oxaliplatin-based chemotherapy in colorectal cancer.

METHODS

We investigated the association between genetic variants in 19 NER pathway genes and the disease control rate (DCR) and progression-free survival (PFS) among 166 colorectal cancer patients who received oxaliplatin-based chemotherapy. Expression quantitative trait loci (eQTL) analysis was performed using the Genotype-Tissue Expression (GTEx) portal. Gene harboring significant SNP was overexpressed or knocked down to demonstrate the effect on cell phenotypes with or without oxaliplatin treatment.

RESULTS

We found that rs5030740, located in the 3'-untranslated region (3'-UTR) of RPA1, was associated with DCR [OR = 2.99 (1.33-5.69), P = 4.00 × 10^-3] and PFS [HR = 1.86 (1.30-2.68), P = 7.39 × 10^-4]. The C allele was significantly associated with higher RPA1 mRNA expression levels according to eQTL analysis (P = 0.010 for sigmoid colon and P = 0.004 for transverse colon). The C allele of rs5030740 disrupted let-7e-5p binding to enhance RPA1 expression. Functionally, RPA1 knockdown inhibited cell proliferation and promoted cell apoptosis, whereas RPA1 overexpression promoted proliferation and suppressed apoptosis. Furthermore, low RPA1 expression increased sensitivity to oxaliplatin in colon cancer cells and inhibited proliferation after oxaliplatin treatment.

CONCLUSIONS

Our findings demonstrate an association between rs5030740 and the DCR and PFS of colorectal cancer patients. RPA1 functions as a putative oncogene in tumorigenesis by reducing sensitivity to oxaliplatin and could serve as a potential prognostic biomarker in colorectal cancer.

Targeted multiplex proteomics for molecular prescreening and biomarker discovery in metastatic colorectal cancer

Protein biomarkers are widely used in cancer diagnosis, prognosis, and prediction of treatment response. Here we introduce the use of targeted multiplex proteomics (TMP) as a tool to simultaneously measure a panel of 54 proteins involved in oncogenic, tumour suppression, drug metabolism and resistance, in patients with metastatic colorectal cancer (mCRC). TMP provided valuable diagnostic information by unmasking an occult neuroendocrine differentiation and identifying a misclassified case based on abnormal proteins phenotype. No significant differences in protein levels between unpaired primary and metastatic samples were observed. Four proteins were found differentially expressed in KRAS-mutant as compared to wild-type tumours (overexpressed in mutant: KRAS, EGFR; overexpressed in wild-type: TOPO1, TOP2A). Survival analyses revealed the association between mesothelin expression and poor overall survival, whereas lack of PTEN protein expression associated with lower progression-free survival with anti-EGFR-based therapy in the first-line setting for patients with RAS wild-type tumour. Finally, outlier analysis identified putative targetable proteins in 65% of patients lacking a targetable genomic alteration. Our data show that TMP constitutes a promising, novel molecular prescreening tool in mCRC to identify protein expression alterations that may impact on patient outcomes and more precisely guide patient eligibility to clinical trials with novel targeted experimental therapies.

MicroRNA-765 sensitizes osteosarcoma cells to cisplatin via downregulating APE1 expression

Objectives

Osteosarcoma (OS) is the most common bone cancer diagnosed in children and adolescents. Expression of APE1 is commonly increased in OS, and this is negatively correlated with a sensitivity to platinum and a favorable prognosis. However, the mechanism underlying high APE1 expression in OS is not fully understood.

Methods

A bioinformatics analysis of the APE1 3’-UTR combined with previous microarray data was used to identify miRNAs that regulate APE1 expression. The effects of miR-765 on cisplatin (cDDP) sensitivity were estimated in OS cell lines (9901 and HOS) and BALB/c mice (n=4 per group). The relative expression and association between miR-765 and APE1 were assessed in a cohort of OS patients (n=43 in total) with Kaplan-Meier and Cox proportional hazards regression. All statistical tests were two-sided and p<0.05 was considered significant.

Results

Bioinformatics analysis implied that miR-765 may target APE1. Luciferase assay and WB showed that miR-765 bound directly to the 3’-UTR of APE1 and downregulated APE1 expression in OS cells. Further experiments revealed that miR-765 sensitized OS cells to cisplatin and was associated with decreased DNA repair activity. In vivo analyses suggested the sensitivity of cisplatin in xenograft OS tissues was increased after injection with miR-765 agomir. The clinical data showed a negative correlation between miR-765 and APE1 expression (r=0.307, p=0.045). Log-rank test revealed that OS patients with positive expression of miR-765 obtained a significantly longer survival than those with negative expression (22.0 vs. 9.0 months, p=0.001), which is just the opposite with respect to APE1 expression (12.00 vs. 22.00 months, p=0.039). The Cox regression analysis found miR-765 may be an independent prognostic factor for OS survival (p=0.007, HR=0.389, 95% CI: 0.196-0.772).

Conclusion

miR-765 sensitizes OS cells to cisplatin and impedes DNA damage repair through the downregulation of APE1. High expression of miR-765 may benefit OS patient survival, making it a viable target for reversing cisplatin-induced resistance in OS patients.

New Insights into Mechanisms of Cisplatin Resistance: From Tumor Cell to Microenvironment

Although cisplatin has been a pivotal chemotherapy drug in treating patients with various types of cancer for decades, drug resistance has been a major clinical impediment. In general, cisplatin exerts cytotoxic effects in tumor cells mainly through the generation of DNA-platinum adducts and subsequent DNA damage response. Accordingly, considerable effort has been devoted to clarify the resistance mechanisms inside tumor cells, such as decreased drug accumulation, enhanced detoxification activity, promotion of DNA repair capacity, and inactivated cell death signaling. However, recent advances in high-throughput techniques, cell culture platforms, animal models, and analytic methods have also demonstrated that the tumor microenvironment plays a key role in the development of cisplatin resistance. Recent clinical successes in combination treatments with cisplatin and novel agents targeting components in the tumor microenvironment, such as angiogenesis and immune cells, have also supported the therapeutic value of these components in cisplatin resistance. In this review, we summarize resistance mechanisms with respect to a single tumor cell and crucial components in the tumor microenvironment, particularly focusing on favorable results from clinical studies. By compiling emerging evidence from preclinical and clinical studies, this review may provide insights into the development of a novel approach to overcome cisplatin resistance.

HLA-DQB1 expression on tumor cells is a novel favorable prognostic factor for relapse in early-stage lung adenocarcinoma

Background: Postoperative recurrence is the main cause of a poor prognosis in early-stage lung adenocarcinoma (LUAD). Factors that can predict recurrence risk are critically needed.

Materials and methods: In this study, we designed a screening procedure based on gene profile data and performed validation using TCGA and Daping hospital’s cohorts. Differentially expressed genes (DEGs) between patients with recurrence-free survival (RFS) <1 year and RFS >3 years were identified, overlapping genes among these DEGs were selected as candidate biomarkers. A Cox proportional hazards model, immunohistochemistry and Kaplan-Meier survival analysis were performed to validate these biomarkers in two distinct validation sets.

Results:SFTPB, SFTPD, SFTA1P, HLA-DQB1, ITGB8, ANLN, and LRRN1 were overlapped both in TCGA and Daping discovery sets. The Cox proportional hazards model analysis of the TCGA validation set showed that HLA-DQB1 was an independent prognostic factor for RFS (HR=0.686, 95% CI, 0.542–0.868). Immunohistochemistry and Kaplan-Meier analysis in Daping validation sets confirmed HLA-DQB1 expression on tumor cells (not interstitial cells) to be an effective predictor of postoperative recurrence. Further examination revealed that the level of HLA-DQB1 expression on tumor cells was positively correlated with CD4- and CD8-positive lymphocyte infiltration into the tumor.

Conclusion: All results indicate that high expression of HLA-DQB1 on tumor cells is a good prognostic marker in early-stage LUAD, and the mechanism may be related to anti-tumor immune activity.

Simultaneous Interrogation of Cancer Omics to Identify Subtypes With Significant Clinical Differences

Recent advances in high-throughput sequencing have accelerated the accumulation of omics data on the same tumor tissue from multiple sources. Intensive study of multi-omics integration on tumor samples can stimulate progress in precision medicine and is promising in detecting potential biomarkers. However, current methods are restricted owing to highly unbalanced dimensions of omics data or difficulty in assigning weights between different data sources. Therefore, the appropriate approximation and constraints of integrated targets remain a major challenge. In this paper, we proposed an omics data integration method, named high-order path elucidated similarity (HOPES). HOPES fuses the similarities derived from various omics data sources to solve the dimensional discrepancy, and progressively elucidate the similarities from each type of omics data into an integrated similarity with various high-order connected paths. Through a series of incremental constraints for commonality, HOPES can take both specificity of single data and consistency between different data types into consideration. The fused similarity matrix gives global insight into patients' correlation and efficiently distinguishes subgroups. We tested the performance of HOPES on both a simulated dataset and several empirical tumor datasets. The test datasets contain three omics types including gene expression, DNA methylation, and microRNA data for five different TCGA cancer projects. Our method was shown to achieve superior accuracy and high robustness compared with several benchmark methods on simulated data. Further experiments on five cancer datasets demonstrated that HOPES achieved superior performances in cancer classification. The stratified subgroups were shown to have statistically significant differences in survival. We further located and identified the key genes, methylation sites, and microRNAs within each subgroup. They were shown to achieve high potential prognostic value and were enriched in many cancer-related biological processes or pathways.

Serum APE1 as a predictive marker for platinum-based chemotherapy of non-small cell lung cancer patients

Purpose

To define the role of the DNA repair protein apurinic/apyrimidinic endonuclease 1 (APE1) in predicting the prognosis and chemotherapeutic response of non-small cell lung cancer patients receiving platinum-containing chemotherapy.

Results

Our investigations found that serum APE1 level was significantly elevated in 229 of 412 NSCLC patients and correlated with its level in tissue (r² = 0.639, p < 0.001). The elevated APE1 level in both tissue and serum of patients prior to chemotherapy was associated with worse progression-free survival (HR: 2.165, p < 0.001, HR: 1.421, p = 0.012), but not with overall survival. After 6 cycles of chemotherapy, a low APE1 serum level was associated with better overall survival (HR: 0.497, p = 0.010).

Experimental Design

We measured APE1 protein levels in biopsy tissue from 172 NSCLC patients and sera of 412 NSCLC patients receiving platinum-based chemotherapy by immunohistochemistry and a newly established sensitive and specific enzyme-linked immunosorbent assay, respectively. APE1 levels in sera of 523 healthy donors were also determined as control.

Conclusions

Our studies indicate that APE1 is a biomarker for predicting prognosis and therapeutic efficacy in NSCLC. The chemotherapy-naïve serum APE1 level, which correlated with its tissue level inversely associated with progression-free survival of platinum-containing doublet chemotherapy, whereas post-treatment serum APE1 level was inversely associated with overall survival.

Loss of CDX2 gene expression is associated with DNA repair proteins and is a crucial member of the Wnt signaling pathway in liver metastasis of colorectal cancer

Caudal type homeobox 2 (CDX2) has been well-established as a diagnostic marker for colorectal cancer (CRC); however, less is known about its regulation, particularly its potential interactions with the DNA repair proteins, adenomatous polyposis coli (APC) and β-catenin, in a non-transcriptional manner. In the present study, the protein expression of CDX2 was analyzed, depending on the expression of the DNA repair proteins, mismatch repair (MMR), O6-methylguanine DNA methyltransferase (MGMT) and excision repair cross-complementing 1 (ERCC1), and its importance in Wnt signaling was also determined. A total of 101 liver metastases were punched into tissue microarray (TMA) blocks and serial sections were cut for immunohistochemistry. For each protein, an immunoreactive score was generated according to literature data and the scores were fitted to TMA. Subsequently, statistical analysis was performed to compare the levels of expression with each other and with clinical data. CDX2 loss of expression was observed in 38.5% of the CRC liver metastasis cases. A statistically significant association between CDX2 and each of the investigated MMRs was observed: MutL Homolog 1 (P<0.01), MutS protein Homolog (MSH) 2 (P<0.01), MSH6 (P<0.01), and postmeiotic segregation increased 2 (P=0.040). Furthermore, loss of MGMT and ERCC1 was also associated with CDX2 loss (P=0.039 and P<0.01, respectively). In addition, CDX2 and ERCC1 were inversely associated with metastatic tumor size (P=0.038 and P=0.027, respectively). Sustained CDX2 expression was associated with a higher expression of cytoplasmic/membranous β-catenin and with nuclear APC expression (P=0.042 and P<0.01, respectively). In conclusion, CDX2 loss of expression was not a rare event in liver metastasis of CRC and the results suggested that CDX2 may be involved in mechanisms resulting in the loss of DNA repair protein expression, and in turn methylation; however, its exact function in this context remains to be elucidated.

Methodological quality evaluation of systematic reviews or meta-analyses on ERCC1 in non-small cell lung cancer: a systematic review

PURPOSES

To assess the methodological quality of systematic reviews (SRs) or meta-analysis concerning the predictive value of ERCC1 in platinum chemotherapy of non-small cell lung cancer.

METHODS

We searched the PubMed, EMbase, Cochrane library, international prospective register of systematic reviews, Chinese BioMedical Literature Database, China National Knowledge Infrastructure, Wan Fang and VIP database for SRs or meta-analysis. The methodological quality of included literatures was evaluated by risk of bias in systematic review (ROBIS) scale.

RESULTS

Nineteen eligible SRs/meta-analysis were included. The most frequently searched databases were EMbase (74%), PubMed, Medline and CNKI. Fifteen SRs did additional retrieval manually, but none of them retrieved the registration platform. 47% described the two-reviewers model in the screening for eligible original articles, and seven SRs described the two reviewers to extract data. In methodological quality assessment, inter-rater reliability Kappa was 0.87 between two reviewers. Research question were well related to all SRs in phase 1 and the eligibility criteria was suitable for each SR, and rated as 'low' risk bias. But the 'high' risk bias existed in all the SRs regarding methods used to identify and/or select studies, and data collection and study appraisal. More than two-third of SRs or meta-analysis were finished with high risk of bias in the synthesis, findings and the final phase.

CONCLUSIONS

The study demonstrated poor methodological quality of SRs/meta-analysis assessing the predictive value of ERCC1 in chemotherapy among the NSCLC patients, especially the high performance bias. Registration or publishing the protocol is recommended in future research.

Prevalence of βIII-tubulin (TUBB3) expression in human normal tissues and cancers

Microtubules are multifunctional cytoskeletal proteins that are involved in crucial cellular roles including maintenance of cell shape, intracellular transport, meiosis, and mitosis. Class III beta-tubulin (βIII-tubulin, also known as TUBB3) is a microtubule protein, normally expressed in cells of neuronal origin. Its expression was also reported in various other tumor types, such as several types of lung cancer, ovarian cancer, and esophageal cancer. TUBB3 is of clinical relevance as overexpression has been linked to poor response to microtubule-targeting anti-cancer drugs such as taxanes. To systematically investigate the epidemiology of TUBB3 expression in normal and neoplastic tissues, we used tissue microarrays for analyzing the immunohistochemically detectable expression of TUBB3 in 3911 tissue samples from 100 different tumor categories and 76 different normal tissue types. At least 1 tumor with weak expression could be found in 93 of 100 (93%) different tumor types, and all these 93 entities also had at least 1 tumor with strong positivity. In normal tissues, a particularly strong expression was found in neurons of the brain, endothelium of blood vessels, fibroblasts, spermatogenic cells, stroma cells, endocrine cells, and acidophilic cells of the pituitary gland. In tumors, strong TUBB3 expression was most frequently found in various brain tumors (85%-100%), lung cancer (35%-80%), pancreatic adenocarcinoma (50%), renal cell carcinoma (15%-80%), and malignant melanoma (77%). In summary, these results identify a broad spectrum of cancers that can at least sporadically express TUBB3. Testing of TUBB3 in cancer types eligible for taxane-based therapies could be helpful to identify patients who might best benefit from this treatment.

Expression of ERCC1, RRM1, TUBB3 in correlation with apoptosis repressor ARC, DNA mismatch repair proteins and p53 in liver metastasis of colorectal cancer

Liver metastasis in colorectal cancer is common and the primary treatment is chemotherapy. To date, there is no routinely used test in clinical practice to predict the effectiveness of conventional chemotherapy. Therefore, biomarkers with predictive value for conventional chemotherapy would be of considerable benefit in treatment planning. We analysed three proteins [excision repair cross-complementing 1 (ERCC1), ribonucleoside-diphosphate reductase 1 (RRM1) and class III β-tubulin (TUBB3)] in colorectal cancer liver metastasis. We used tissue microarray slides with 101 liver metastasis samples, stained for ERCC1, RRM1 and TUBB3 and established scoring systems (fitted for tissue microarray) for each protein. In statistical analysis, we compared the expression of ERCC1, RRM1 and TUBB3 to mismatch proteins (MLH1, MSH2, MSH6 and PMS2), p53 and to apoptosis repressor protein (ARC). Statistically significant correlations were found between ERCC1, TUBB3 and MLH1, MSH2 and RRM1 and MSH2, MSH6. Noteworthy, our analysis revealed a strong significant correlation between cytoplasmic ARC expression and RRM1, TUBB3 (p=0.000 and p=0.001, respectively), implying an additional role of TUBB3 and RRM1 not only in therapy resistance, but also in the apoptotic machinery. Our data strengthens the importance of ERCC1, TUBB3 and RRM1 in the prediction of chemotherapy effectiveness and suggest new functional connections in DNA repair, microtubule network and apoptotic signaling (i.e. ARC protein). In conclusion, we showed the importance and need of predictive biomarkers in metastasized colorectal cancer and pointed out the relevance not only of single predictive markers but also of their interactions with other known and newly explored relations between different signaling pathways.

APE1 overexpression is associated with poor survival in patients with solid tumors: a meta-analysis

APE1 is known as a key mediator of DNA damage repair pathways, and its clinical significance in different types of cancer is well studied. Herein, we performed a meta-analysis to determine the association of APE1 expression and survival in different types of solid cancer. We searched all eligible publications in PubMed, Web of Science and Embase platforms from inception to January 2017 and found 15 relevant manuscripts. Overall survival (OS), 12- and 36-month survival rates, and hazard ratios (HRs) were extracted and analyzed. Heterogeneity and publication bias were also assessed. A subgroup analysis of the different subcellular locations of APE1 was also conducted. Patients with higher APE1 levels demonstrated lower 12- and 36-month survival rates than those with low APE1 levels (HR 2.00, 95% CI 1.33–3.00, P = 0.0009; HR 1.84, 95% CI 1.19–2.84, P = 0.006). Importantly, the pooled analysis showed that high levels of APE1 predict shorter OS (HR 1.44, 95% CI 1.13–1.83, P = 0.003). Subgroup analysis revealed that both nuclear and cytoplasmic expression levels of APE1 are important indicators of poor prognosis in solid tumors.

Association between the XRCC1 polymorphisms and clinical outcomes of advanced NSCLC treated with platinum-based chemotherapy: a meta-analysis based on the PRISMA statement

Background

Base excision repair (BER) pathway is a DNA repair pathway that is important in carcinogenesis and in response to DNA-damaging chemotherapy. XRCC1 is one of important molecular markers for BER. So far, the role of XRCC1 polymorphisms with clinical outcomes of advanced NSCLC treated with platinum-based chemotherapy is inconclusive. To explore the relationship between XRCC1 polymorphisms and platinum-based chemotherapy in advanced NSCLC patients, we performed this meta-analysis.

Methods

Crude odds ratios (ORs), Cox proportional hazard ratios (HRs) with the corresponding 95% confidence intervals (CIs) were adopted to assess the strength of association between XRCC1 polymorphisms and response rate, Overall survival (OS) and progression free survival (PFS) of advanced NSCLC treated with platinum-based chemotherapy. Q test and I² test were used for the assessment of heterogeneity. Subgroup analyses were conducted when heterogeneity exists. Begg’s funnel plots and Egger’s linear regression test were used to estimate publication bias. Sensitivity analysis was performed to evaluate the stability of the result.

Results

A total of 19 studies including 2815 individuals were eligible for the analysis, results showed XRCC1 194Arg allele was negatively associated with the objective response rate relative to 194Trp, and results of homozygous model, dominant model and heterozygous model suggested a gene dosage effect negative correlation between 194Arg allele and objective response rate(ArgArg vs TrpTrp: OR = 0.64(95%CI: 0.44-0.91); ArgArg + TrpArg vs TrpTrp: OR = 0.79(95%CI: 0.57-1.11); TrpArg vs TrpTrp: OR = 1.05(95%CI: 0.73-1.51)). XRCC1 399Gln may indicate favorable overall survival (GlnGln + GlnArg vs ArgArg: HR = 0.65(95%CI: 0.43–0.98)) and favorable PFS (GlnGln vs ArgArg: HR = 0.72(95%CI: 0.48–0.97)) in Asian patients; while in Caucasian patients, XRCC1 399Gln indicated poorer overall survival (GlnGln vs ArgArg: HR = 2.29(95%CI: 1.25–3.33)).

Conclusions

Our results indicated that in NSCLC patients treated with platinum-based regimen, XRCC1 194Arg allele suggest poor objective response rate, the GlnGln genotype of XRCC1 399 suggest poorer overall survival in Caucasian patients, and longer PFS in Asian patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3487-y) contains supplementary material, which is available to authorized users.

Exploiting the Ref-1-APE1 node in cancer signaling and other diseases: from bench to clinic

Reduction-oxidation factor 1-apurinic/apyrimidinic endonuclease (Ref-1/APE1) is a critical node in tumor cells, both as a redox regulator of transcription factor activation and as part of the DNA damage response. As a redox signaling protein, Ref-1/APE1 enhances the transcriptional activity of STAT3, HIF-1α, nuclear factor kappa B, and other transcription factors to promote growth, migration, and survival in tumor cells as well as inflammation and angiogenesis in the tumor microenvironment. Ref-1/APE1 is activated in a variety of cancers, including prostate, colon, pancreatic, ovarian, lung and leukemias, leading to increased aggressiveness. Transcription factors downstream of Ref-1/APE1 are key contributors to many cancers, and Ref-1/APE1 redox signaling inhibition slows growth and progression in a number of tumor types. Ref-1/APE1 inhibition is also highly effective when paired with other drugs, including standard-of-care therapies and therapies targeting pathways affected by Ref-1/APE1 redox signaling. Additionally, Ref-1/APE1 plays a role in a variety of other indications, such as retinopathy, inflammation, and neuropathy. In this review, we discuss the functional consequences of activation of the Ref-1/APE1 node in cancer and other diseases, as well as potential therapies targeting Ref-1/APE1 and related pathways in relevant diseases. APX3330, a novel oral anticancer agent and the first drug to target Ref-1/APE1 for cancer is entering clinical trials and will be explored in various cancers and other diseases bringing bench discoveries to the clinic.

In silico identification of potential key regulatory factors in smoking-induced lung cancer

Background

Lung cancer is a leading cause of cancer-related death worldwide and is the most commonly diagnosed cancer. Like other cancers, it is a complex and highly heterogeneous disease involving multiple signaling pathways. Identifying potential therapeutic targets is critical for the development of effective treatment strategies.

Methods

We used a systems biology approach to identify potential key regulatory factors in smoking-induced lung cancer. We first identified genes that were differentially expressed between smokers with normal lungs and those with cancerous lungs, then integrated these differentially expressed genes (DEGs) with data from a protein-protein interaction database to build a network model with functional modules for pathway analysis. We also carried out a gene set enrichment analysis of DEG lists using the Kinase Enrichment Analysis (KEA), Protein-Protein Interaction (PPI) hubs, and KEGG (Kyoto Encyclopedia of Genes and Genomes) databases.

Results

Twelve transcription factors were identified as having potential significance in lung cancer (CREB1, NUCKS1, HOXB4, MYCN, MYC, PHF8, TRIM28, WT1, CUX1, CRX, GABP, and TCF3); three of these (CRX, GABP, and TCF) have not been previously implicated in lung carcinogenesis. In addition, 11 kinases were found to be potentially related to lung cancer (MAPK1, IGF1R, RPS6KA1, ATR, MAPK14, MAPK3, MAPK4, MAPK8, PRKCZ, and INSR, and PRKAA1). However, PRKAA1 is reported here for the first time. MEPCE, CDK1, PRKCA, COPS5, GSK3B, BRCA1, EP300, and PIN1 were identified as potential hubs in lung cancer-associated signaling. In addition, we found 18 pathways that were potentially related to lung carcinogenesis, of which 12 (mitogen-activated protein kinase, gonadotropin-releasing hormone, Toll-like receptor, ErbB, and insulin signaling; purine and ether lipid metabolism; adherens junctions; regulation of autophagy; snare interactions in vesicular transport; and cell cycle) have been previously identified.

Conclusion

Our systems-based approach identified potential key molecules in lung carcinogenesis and provides a basis for investigations of tumor development as well as novel drug targets for lung cancer treatment.

DNA base excision repair proteins APE-1 and XRCC-1 are overexpressed in oral tongue squamous cell carcinoma

BACKGROUND

DNA repair systems play a critical role in protecting the human genome from damage caused by carcinogens. Modifications in DNA repair genes may be responsible for tumor development and resistance of malignant cells to chemotherapeutic agents. The major pathway for oxidative DNA damage repair is the base excision repair pathway. This study aimed to assess the immunoexpression of DNA repair proteins APE-1 and XRCC-1 and its association with clinical, histologic, and survival parameters in oral tongue squamous cell carcinoma, to investigate a possible role for those proteins in tumor behavior.

METHODS

The expression of APE-1 and XRCC-1 was evaluated by immunohistochemistry in 82 cases of oral tongue squamous cell carcinoma. Histopathological grading was performed for each case. Pearson's chi-square and Fisher's exact tests were used to determine the association between protein expressions and clinicopathological features of tumors, whereas Kaplan-Meier curves and Cox regression were used to analyze disease-specific and disease-free survival. Statistical significance was set at P ≤ 0.05.

RESULTS

APE-1 was highly expressed in the nucleus and cytoplasm in 64.6% of cases, and XRCC-1 showed overexpression only in the nucleus in 61% of cases. High expression of XRCC-1 was significantly associated with tumors at early clinical stages (I and II, P < 0.01) and nodal status (P = 0.03). Both proteins were not associated with other clinical parameters, histopathological grading, or survival.

CONCLUSIONS

DNA base excision repair proteins APE-1 and XRCC-1 are upregulated in oral tongue squamous cell carcinoma, and XRCC-1 expression is associated with better clinical staging and nodal status.

Reduced apurinic/apyrimidinic endonuclease activity enhances the antitumor activity of oxymatrine in lung cancer cells

Lung cancer is the leading cause of cancer-related deaths worldwide and is associated with a very poor outcome. Oxymatrine exerts antitumor effects by inducing apoptosis and inhibiting the proliferation of different cancer cells; however, the anticancer effects and mechanism of action of oxymatrine have not been evaluated sufficiently in human lung cancer cells. Thus, the present study aimed to investigate the anticancer effects of oxymatrine in human lung cancer cells and identify the molecular mechanisms underlying these effects. MTT assays demonstrated that oxymatrine significantly inhibited the proliferation of A549 and H1299 cells in a time- and dose-dependent manner. In addition, flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling assays suggested that oxymatrine treatment may induce lung cancer cell apoptosis in a dose-dependent manner. Furthermore, we detected that oxymatrine induced a significant increase in DNA damage and the expression of PARP and phosphorylated H2AX, and a significant decrease in that of nuclear APE1 and AP endonuclease activity in A549 cells. APE1 knockdown cells (APE1shRNA) plus oxymatrine treatment reduced cells proliferation and induced apoptosis more seriously than control shRNA cells. This appeared to be a consequence of an increase in the number of apurinic/apyrimidinic (AP) sites, DNA damage, PARP and H2AX phosphorylation, which together resulted in the induction of apoptosis. In contrast, the sensitizing effects of APE1 overexpression plus oxymatrine treatment did not occur in APEOE cells. These findings reveal a potential mechanism of action for oxymatrine-induced apoptosis and suggest that oxymatrine is a promising potential therapeutic agent for the treatment of lung cancer.

Combination gemcitabine/cisplatin therapy and ERCC1 expression for resected pancreatic adenocarcinoma: Results of a Phase II prospective trial

BACKGROUND

Standard adjuvant treatment for pancreatic adenocarcinoma (PDAC) is gemcitabine [Gem(CONKO-001: Gem vs. placebo DFS:13.4 vs. 6.7 mo; P < 0.001; OS:22.8 vs. 20.2 mo; P = 0.01)]. Addition of cisplatin (Cis) to Gem has resulted in increased PFS for advanced and metastatic disease, which may be predicted by low expression of excision repair cross-complementing group-1 (ERCC1), the key enzyme in nucleotide excision repair. This Phase II prospective trial assesses outcomes of patients treated with adjuvant Gem/Cis, stratifying results by tumor ERCC1 expression.

METHODS

Patients with resected PDAC were enrolled (2010-2013) and received Gem(1,000 mg/m(2) )/Cis(50 mg/m(2) ). Tumor ERCC1 expression was evaluated by immunohistochemistry and dichotomized into low or high expression. Primary outcomes were recurrence-free and overall survival (RFS/OS).

RESULTS

Of 22 pts, 16(73%) were Stage IIB, 5(23%) Stage IIA, and 1(4%) Stage IA. Grade 3/4 toxicity occurred in 13 pts (59%); neutropenia was most common (n = 9;41%). Median follow-up was 37.5 months. Median RFS was 16.7 mo; OS was 35.5 mo. Low ERCC1 (n = 15;75%) compared to high ERCC1 (n = 5;25%) was not associated with improved RFS (12.4 vs. 16.7 mo; P = 0.68) or OS (Median not reached vs. 21.6 mo; P = 0.22).

CONCLUSIONS

Adjuvant Gem/Cis is feasible in patients with resected pancreatic adenocarcinoma. RFS and OS for Gem/Cis appear promising compared to historic control. Tumor ERCC1 expression can be reliably evaluated, and low expression is present in most patients. J. Surg. Oncol. 2016;114:336-341. © 2016 Wiley Periodicals, Inc.

DNA Repair Genes ERCC1 and BRCA1 Expression in Non-Small Cell Lung Cancer Chemotherapy Drug Resistance

Background

Surgery combined with chemotherapy is an important therapy for non-small cell lung cancer (NSCLC). However, chemotherapy drug resistance seriously hinders the curative effect. Studies show that DNA repair genes ERCC1 and BRCA1 are associated with NSCLC chemotherapy, but their expression and mechanism in NSCLC chemotherapy drug-resistant cells has not been elucidated.

Material/Methods

NSCLC cell line A549 and drug resistance cell line A549/DDP were cultured. Real-time PCR and Western blot analyses were used to detect ERCC1 and BRCA1 mRNA expression. A549/DDP cells were randomly divided into 3 groups: the control group; the siRNA-negative control group (scramble group); and the siRNA ERCC1 and BRCA1siRNA transfection group. Real-time PCR and Western blot analyses were used to determine ERCC1 and BRCA1 mRNA and protein expression. MTT was used to detect cell proliferation activity. Caspase 3 activity was tested by use of a kit. Western blot analysis was performed to detect PI3K, AKT, phosphorylated PI3K, and phosphorylated AKT protein expression.

Results

ERCC1 and BRCA1 were overexpressed in A549/DDP compared with A549 (P<0.05). ERCC1 and BRCA1siRNA transfection can significantly reduce ERCC1 and BRCA1 mRNA and protein expression (P<0.05). Downregulating ERCC1 and BRCA1 expression obviously inhibited cell proliferation and increased caspase 3 activity (P<0.05). Downregulating ERCC1 and BRCA1 significantly decreased PI3K and AKT phosphorylation levels (P<0.05).

Conclusions

ERCC1 and BRCA1 were overexpressed in NSCLC drug-resistant cells, and they regulated lung cancer occurrence and development through the phosphorylating PI3K/AKT signaling pathway.

AT101 exerts a synergetic efficacy in gastric cancer patients with 5-FU based treatment through promoting apoptosis and autophagy

Gastric cancer remains a disease with a high mortality rate despite of multiple therapeutic strategies. So far, it is very important to develop new treatment approaches to improve current therapeutic efficacy in gastric cancer. Apurinic/apyrimidinic endonuclease (APE1) involves in DNA base excision repair (BER) during DNA damage pathway. APE1 was found to be associated with poor overall survival with gastric cancer patients. In the in vitro experiment, we tested APE1 inhibitor-AT101 could potently inhibit gastric cancer cell growth and further induce cancer cell apoptosis and autophagy through p53-dependent pathway. Downregulation of APE1 by AT101 has ability to suppress gastric cancer cell migration and renewal through inhibition of CD133, Nanog and LC3expression. Based on findings that Her-2 positive expression cases has poor prognosis from our dataset and TCGA database, we investigated the role of AT101 in synergetic efficacy with 5-FU treatment in Her-2 overexpression gastric cancer in vivo, indicating that AT101 is able to enhance 5-FU in the shrinkage of xenograft mice tumor and induction of cell apoptosis. In summary, the data obtained from our study showed APE1 is guided as a potential therapeutic target for gastric cancer. AT101 could be regarded as a potent inhibitor to promote chemotherapeutic sensitivity in patients with gastric cancer.

Expression of BRCA1, a factor closely associated with relapse-free survival, in patients who underwent neoadjuvant chemotherapy with docetaxel, cisplatin, and fluorouracil for squamous cell carcinoma of the esophagus

PURPOSE

The aim of this study was to identify the biomarkers associated with chemotherapeutic efficacy and long-term survival for patients with advanced squamous cell carcinoma of the esophagus (SCCE) who had received neoadjuvant chemotherapy with docetaxel and cisplatin plus 5-fluorouracil (NAC-DCF).

METHODS

This study included 45 patients with advanced SCCE who received NAC-DCF between 2008 and 2012. The NAC-DCF was conducted as a phase II study (UMIN000007408). The expressions of excision repair cross-complementing-1 (ERCC1), class III beta-tubulin, breast cancer susceptibility gene I (BRCA1), and thymidylate synthase were investigated simultaneously in the pre-treatment endoscopic tumor biopsy samples.

RESULTS

A multivariate logistic regression analysis indicated that pathological responses were significantly associated with tumors with low ERCC1 expression (P = 0.016) and with tumors with high BRCA1 expression (P = 0.030). The multivariate Cox proportional hazard model analysis for relapse-free survival revealed high BRCA1 expression (P = 0.031, hazards ratio 4.39) as the factor associated with survival.

CONCLUSIONS

Low ERCC1 expression and high BRCA1 expression in patients with SCCE were associative biomarkers for chemotherapeutic efficacy. High BRCA1 expression was considered the factor associated with survival. These findings may be helpful for tailoring chemotherapy.

Expression of TS, RRM1, ERCC1, TUBB3 and STMN1 Genes in Tissues of Non-small Cell Lung Cancer and its Significance in Guiding Postoperative Adjuvant Chemotherapy

BACKGROUND

To explore the expression of TS, RRM, ERCC1, TUBB3 and STMN1 genes in the tissues of patients with non-small cell lung cancer (NSCLC) and its significance in guiding the postoperative adjuvant chemotherapy.

MATERIALS AND METHODS

Real time polymerase chain reaction (PCR) was applied to detect the expression of TS, RRM, ERCC1, TUBB3 and STMN1 genes in the tissues of NSCLC patients so as to analyze the relationship between the expression of each gene and the clinical characteristics and to guide the postoperative individualized chemotherapy according to the detection results of NSCLC patients.

RESULTS

Expression of TS gene was evidently higher in patients with adenocarcinoma than those with non-adenocarcinoma (P=0.013) and so was the expression of ERCC1 (P=0.003). The expression of TUBB3 gene was obviously higher in NSCLC patients in phases I/II and IV than those in phase III (P1=0.021; P2=0.004), and it was also markedly higher in patients without lymph node metastasis than those with (P=0.008). The expression of STMN1 gene was apparently higher in patients in phase I/II than those in phase IV (P=0.002). There was no significant difference between the rest gene expression and the clinical characteristics of NSCLC patients (P>0.05). Additionally, the disease- free survival (DFS) was significantly longer in patients receiving gene detections than those without (P=0.021).

CONCLUSIONS

The selection of chemotherapeutic protocols based singly on patients' clinical characteristics has certain blindness. However, the detection of tumor-susceptible genes can guide the postoperative adjuvant chemotherapy and prolong the DFS of NSCLC patients.

Cisplatin resistance and opportunities for precision medicine

Cisplatin is one of the most commonly used chemotherapy drugs, treating a wide range of cancer types. Unfortunately, many cancers initially respond to platinum treatment but when the tumor returns, drug resistance frequently occurs. Resistance to cisplatin is attributed to three molecular mechanisms: increased DNA repair, altered cellular accumulation, and increased drug inactivation. The use of precision medicine to make informed decisions on a patient's cisplatin resistance status and predicting the tumor response would allow the clinician to tailor the chemotherapy program based on the biology of the disease. In this review, key biomarkers of each molecular mechanism will be discussed along with the current clinical research. Additionally, known polymorphisms for each biomarker will be discussed in relation to their influence on cisplatin resistance.

Minnelide Overcomes Oxaliplatin Resistance by Downregulating the DNA Repair Pathway in Pancreatic Cancer

INTRODUCTION

Oxaliplatin is part of pancreatic cancer therapy in the FOLFIRINOX or GEMOX/XELOX regimen. DNA damage repair is one of the factors responsible for oxaliplatin resistance that eventually develops in this cancer. Triptolide/Minnelide has been shown to be effective against pancreatic cancer in preclinical trials. In this study, we evaluated the efficacy of combination of triptolide and oxaliplatin against pancreatic cancer.

METHODS

Highly aggressive pancreatic cancer cells (MIA PaCa-2 and PANC-1) were treated with oxaliplatin (0-10 μM), low-dose triptolide (50 nM), or a combination of both for 24-48 h. Cell viability, apoptosis, and DNA damage were evaluated by appropriate methods. Nucleotide excision repair pathway components were quantitated using qPCR and Western blot. Combination of low doses of Minnelide and oxaliplatin was tested in an orthotopic murine model of pancreatic cancer.

RESULTS

Proliferation of pancreatic cancer cells was markedly inhibited by combination treatment. Triptolide potentiated apoptotic cell death induced by oxaliplatin and sensitized cancer cells towards oxaliplatin-induced DNA damage by suppressing the oxaliplatin-induced DNA damage repair pathway. Combination of low doses of Minnelide and oxaliplatin inhibited tumor progression by inducing significant apoptotic cell death in these tumors.

CONCLUSIONS

Combination of low doses of Minnelide and oxaliplatin has immense potential to emerge as a novel therapeutic strategy against pancreatic cancer.

Expression of Ribonucleotide Reductase Subunit-2 and Thymidylate Synthase Correlates with Poor Prognosis in Patients with Resected Stages I-III Non-Small Cell Lung Cancer

Biomarkers can help to identify patients with early-stages or locally advanced non-small cell lung cancer (NSCLC) who have high risk of relapse and poor prognosis. To correlate the expression of seven biomarkers involved in DNA synthesis and repair and in cell division with clinical outcome, we consecutively collected 82 tumour tissues from radically resected NSCLC patients. The following biomarkers were investigated using IHC and qRT-PCR: excision repair cross-complementation group 1 (ERCC1), breast cancer 1 (BRCA1), ribonucleotide reductase subunits M1 and M2 (RRM1 and RRM2), subunit p53R2, thymidylate synthase (TS), and class III beta-tubulin (TUBB3). Gene expression levels were also validated in an available NSCLC microarray dataset. Multivariate analysis identified the protein overexpression of RRM2 and TS as independent prognostic factors of shorter overall survival (OS). Kaplan-Meier analysis showed a trend in shorter OS for patients with RRM2, TS, and ERCC1, BRCA1 overexpressed tumours. For all of the biomarkers except TUBB3, the OS trends relative to the gene expression levels were in agreement with those relative to the protein expression levels. The NSCLC microarray dataset showed RRM2 and TS as biomarkers significantly associated with OS. This study suggests that high expression levels of RRM2 and TS might be negative prognostic factors for resected NSCLC patients.

Development of APE1 enzymatic DNA repair assays: low APE1 activity is associated with increase lung cancer risk

We developed radioactivity-based and fluorescence-based assays for the DNA repair enzyme APE1 and showed that its decreased activity is associated with increased lung cancer risk. This suggests that ‘bad DNA repair’ rather than ‘bad luck’ is involved in cancer etiology.

The key role of DNA repair in removing DNA damage and minimizing mutations makes it an attractive target for cancer risk assessment and prevention. Here we describe the development of a robust assay for apurinic/apyrimidinic (AP) endonuclease 1 (APE1; APEX1), an essential enzyme involved in the repair of oxidative DNA damage. APE1 DNA repair enzymatic activity was measured in peripheral blood mononuclear cell protein extracts using a radioactivity-based assay, and its association with lung cancer was determined using conditional logistic regression with specimens from a population-based case–control study with 96 lung cancer cases and 96 matched control subjects. The mean APE1 enzyme activity in case patients was 691 [95% confidence interval (CI) = 655–727] units/ng protein, significantly lower than in control subjects (mean = 793, 95% CI = 751–834 units/ng protein, P = 0.0006). The adjusted odds ratio for lung cancer associated with 1 SD (211 units) decrease in APE1 activity was 2.0 (95% CI = 1.3–3.1; P = 0.002). Comparison of radioactivity- and fluorescence-based assays showed that the two are equivalent, indicating no interference by the fluorescent tag. The APE1Asp148Glu SNP was associated neither with APE1 enzyme activity nor with lung cancer risk. Taken together, our results indicate that low APE1 activity is associated with lung cancer risk, consistent with the hypothesis that ‘bad DNA repair’, rather than ‘bad luck’, is involved in cancer etiology. Such assays may be useful, along with additional DNA repair biomarkers, for risk assessment of lung cancer and perhaps other cancers, and for selecting individuals to undergo early detection techniques such as low-dose CT.

Clinical evaluation of postoperative chemotherapy based on genetic testing in patients with stage IIIA non-small cell lung cancer

Background

We performed a retrospective analysis to evaluate whether a postoperative chemotherapy selection method based on four tumoral gene expression tests would improve prognosis in patients with stage IIIA non‐small cell lung cancer (NSCLC) after surgery.

Methods

Between January 2007 and July 2011, 148 patients with stage IIIA NSCLC underwent radical lobectomy with four cycles of adjuvant postoperative chemotherapy. Forty‐five patients had tailored treatment plans based on the results of tumoral gene expression tests. The tests consisted of quantitative real‐time polymerase chain reaction analyses to measure the messenger ribonucleic acid levels of the excision repair cross‐complementing gene 1, ribonucleotide reductase Ml, type III β‐tubulin, and thymidylate synthase genes in tumor tissues. One hundred and three patients received conventional chemotherapy. Disease responses were assessed after two cycles and every three months after the first four cycles of chemotherapy. The one and two‐year survival rates and diesease‐free survival (DFS) rates were recorded, and the adverse effects documented.

Results

The one and two‐year DFS rates in the genetically tested group were better than those in the non‐tested group, and the differences were statistically significant (P < 0.05). The two‐year Kaplan–Meier DFS curve analysis results were significantly better in the genetically tested group (X² = 8.228, P = 0.004). The adverse effects during the treatments were not significantly different (P > 0.05) between the two groups.

Conclusions

The chemotherapy selection method based on four tumoral gene expression tests demonstrated its feasibility to improve the efficacy of adjuvant postoperative chemotherapy and benefit stage IIIA NSCLC patients by yielding better DFS without increasing the adverse effects of chemotherapy.