RNA binding motif 4 inhibits the replication of ebolavirus by directly targeting 3'-leader region of genomic RNA

Ebola virus (EBOV) belongs to Filoviridae family possessing single-stranded negative-sense RNA genome, which is a serious threat to human health. Nowadays, no therapeutics have been proven to be successful in efficiently decreasing the mortality rate. RNA binding proteins (RBPs) are reported to participate in maintaining cell integrity and regulation of viral replication. However, little is known about whether and how RBPs participate in regulating the life cycle of EBOV. In our study, we found that RNA binding motif protein 4 (RBM4) inhibited the replication of EBOV in HEK293T and Huh-7 cells by suppressing viral mRNA production. Such inhibition resulted from the direct interaction between the RRM1 domain of RBM4 and the "CU" enrichment elements located in the PE1 and TSS of the 3'-leader region within the viral genome. Simultaneously, RBM4 could upregulate the expression of some cytokines involved in the host innate immune responses to synergistically exert its antiviral function. The findings therefore suggest that RBM4 might serve as a novel target of anti-EBOV strategy.

Prognostic value of RRM1 and its effect on chemoresistance in pancreatic cancer

PURPOSE

Pancreatic cancer (PC) remains a lethal disease, and gemcitabine resistance is prevalent. However, the biomarkers suggestive of gemcitabine resistance remain unclear.

METHODS

Bioinformatic tools identified ribonucleotide reductase catalytic subunit M1 (RRM1) in gemcitabine-related datasets. A cox regression model revealed the predictive value of RRM1 with clinical features. An external clinical cohort confirmed the prognostic value of RRM1. RRM1 expression was validated in gemcitabine-resistant cells in vitro and in orthotopic PC model. CCK8, flow cytometry, transwell migration, and invasion assays were used to explore the effect of RRM1 on gemcitabine-resistant cells. The CIBERSORT algorithm investigated the impact of RRM1 on immune infiltration.

RESULTS

The constructed nomogram based on RRM1 effectively predicted prognosis and was further validated. Moreover, patients with higher RRM1 had shorter overall survival. RRM1 expression was significantly higher in PC tissue and gemcitabine-resistant cells in vitro and in vivo. RRM1 knockdown reversed gemcitabine resistance, inhibited migration and invasion. The infiltration levels of CD4 + T cells, CD8 + T cells, neutrophils, and plasma cells correlated markedly with RRM1 expression, and communication between tumor and immune cells probably depends on NF-κB/mTOR signaling.

CONCLUSION

RRM1 may be a potential marker for prognosis and a target marker for gemcitabine resistance in PC.

Predictive and Prognostic Value of TUBB3, RRM1, APE1, and Survivin Expression in Chemotherapy-Receiving Patients with Advanced Non‑Small Cell Lung Cancer

BACKGROUND

This study aimed to evaluate the expression of class III β-tubulin (TUBB3), ribonucleoside-diphosphate reductase 1 (RRM1), apurinic/apyrimidinic endonuclease 1 (APE1), and survivin in patients with advanced non-small cell lung cancer (NSCLC) to predict response to chemotherapy.

METHODS

TUBB3, RRM1, APE1, and survivin expression levels were determined using immunohistochemistry. Protein expression was validated in Car/Pac-resistant human H1792 and A549 cells. This study included 86 patients, among whom 34 received cisplatin (Cis)/gemcitabine (Gem) and 52 received carboplatin (Car)/paclitaxel (Pac).

RESULTS

Patients with low TUBB3 expression and high RRM1 and survivin expression had higher response rates than those with low RRM1 and survivin expression and high TUBB3 expression in the Car/Pac regimen. The multivariate analysis indicated that TUBB3 and RRM1 were significant independent predictive biomarkers for the Car/Pac regimen; however, there was no association between any protein and overall response in patients treated with this regimen. In the Cis/Gem regimen, only high TUBB3 expression was associated with poor overall survival; however, it did not exhibit a prognostic ability.

CONCLUSION

The expression levels of TUBB3 and RRM1 in NSCLC cells are potential predictive biomarkers, but not prognostic factors, of response to chemotherapy in patients with NSCLC receiving the Car/Pac regimen.

RRM1 is mediated by histone acetylation through gemcitabine resistance and contributes to invasiveness and ECM remodeling in pancreatic cancer

The invasiveness of pancreatic cancer and its resistance to anticancer drugs define its malignant potential, and are considered to affect the peritumoral microenvironment. Cancer cells with resistance to gemcitabine exposed to external signals induced by anticancer drugs may enhance their malignant transformation. Ribonucleotide reductase large subunit M1 (RRM1), an enzyme in the DNA synthesis pathway, is upregulated during gemcitabine resistance, and its expression is associated with worse prognosis for pancreatic cancer. However, the biological function of RRM1 is unclear. In the present study, it was demonstrated that histone acetylation is involved in the regulatory mechanism related to the acquisition of gemcitabine resistance and subsequent RRM1 upregulation. The current in vitro study indicated that RRM1 expression is critical for the migratory and invasive potential of pancreatic cancer cells. Furthermore, a comprehensive RNA sequencing analysis showed that activated RRM1 induced marked changes in the expression levels of extracellular matrix‑related genes, including N‑cadherin, tenascin‑C and COL11A. RRM1 activation also promoted extracellular matrix remodeling and mesenchymal features, which enhanced the migratory invasiveness and malignant potential of pancreatic cancer cells. The present results demonstrated that RRM1 has a critical role in the biological gene program that regulates the extracellular matrix, which promotes the aggressive malignant phenotype of pancreatic cancer.

The Predictive Value of ERCC1, RRM1, and Thymidylate Synthase in Advanced Malignant Pleural Mesothelioma Patients Treated with Platinum-Based Chemotherapy

BACKGROUND

A rare yet severe neoplasia called malignant pleural mesothelioma (MPM) typically manifests itself in advanced stages. Despite some improvements in the treatment of patients with MPM, this malignancy continues to have a detrimental prognosis . The primary goal of the present study was to assess the associatin between ERCC1, RRM1, and thymidylate synthase (TS) expression and disease outcome in patients with malignant pleural mesothelioma (MPM) treated with either pemetrexed plus cisplatin or gemcitabine plus cisplatin.

METHODS

This prospective cohort study was done on ninety-one advanced MPM patients. The patients received either pemetrexed plus platinum (55 of 91) or gemcitabine plus platinum chemotherapy (36 of 91). Tissue biopsy was taken at time of diagnosis. Immunohistochemistry was used to assess the levels of ERCC1, RRM1, and TS transcription in tissue biopsies (paraffin embedded).

RESULTS

Based on the findings, 70% of patients with low expression of TS had low expression of ERCC1, and 68% of patients with high expression of TS had high expression of ERCC1, suggesting  a significat association between ERCC1 expression and TS expression (p=0.005). However, there was no relation between ERCC1 and RRM1 expression patterns (p= 0.296). In patients underwen platinum-based theraphy (n 91), a significant correlation was detected between low ERCC1 median High-scoring and longer progression time (TTP;9.6 v 5.3 months;P< .001) or overall survival (OS) (OS;18.1 v 9.1 months; P<0.001). A significant correlation was found between low TS protein expression and longer time progression (TTP; 11.8 v 5.4 months; P< .001) or OS (OS; 19.8 v 8.5 months; P <0.001) in patients undergoing pemetrexed plus platinum chemotherapy (n 55). Low RRM1 expression was accompanied by high progression free survival (TTP; 10.6 v 3.8 months) and OS (OS; 20.6 v 8.6 months) in patients receiving gemcitabine plus platinum chemotherapy. Based on the multivariate test results, the independent variables significantly affecting OS were tumor stage (HR: 2.3; 95% CI: 1.1-4.9; p= 0.021) and ERCC1 (HR: 2.7; 95% CI: 1.7-4.3; p < 0.001).

CONCLUSION

Decreased TS protein expression can be indicative of greater responsivness to pemtrexed and of longer TTP and OS in individuals with advanced MPM (locally progressed or metastatic) who are receiving pemetrexed-based chemotheraphy. Low ERCC1 expressions in individuals with advanced MPM can predict increased PFS and OS, as well as a better responsivness to platinum-based chemotherapy. In patients with progressed MPM receiving gemcitabine plus cisplatin chemotherapy, lower RRM1 expression was associated with a better prognosis, longer PFS, and longer OS.

Association between TOP2A, RRM1, HER2, ERCC1 expression and response to chemotherapy in patients with non-muscle invasive bladder cancer

Purpose

This study aimed to detect the expression levels of topoisomerase IIα (TOP2A), ribonucleotide reductase catalytic subunit M1 (RRM1),c-erbB-2 (HER2) and excision repair cross complementing group 1 (ERCC1) in non-muscular invasive bladder cancer (NMIBC) and explore the correlation between the expression of these genes and NMBIC sensitivity to pirarubicin or gemcitabine treatment.

Materials and methods

NMIBC patient tissues and the bladder cancer cell lines BIU-87 and KK47 were selected for the exploration of drug sensitivity in vitro. Immunohistochemistry was used to examine protein expression in tissues. Reverse transcription-polymerase chain reaction (RT-qPCR) and a Western blot assay were used to detect the mRNA and protein levels in cells. The cell IC50 value was evaluated by an MTT assay. Flow cytometry was used to sort the cell subpopulations.

Results

In the pirarubicin-treated group, the patients with high TOP2A expression experienced lower recurrence rates than those with low TOP2A expression, whereas TOP2A and HER2 co-expression resulted in higher recurrence rates. The patients with low RRM1 expression, especially those with low ERCC1 expression, experienced lower recurrence rates than the patients with high RRM1 expression in the gemcitabine-treated group. Tumour cells with high TOP2A expression were highly sensitive to pirarubicin, and TOP2A⁺ HER2^- cells were more sensitive to pirarubicin than TOP2A⁺ HER2⁺ cells. Cells with low RRM1 expression levels were sensitive to gemcitabine, and RRM1⁻ERCC1^- cells were more sensitive to gemcitabine than RRM1⁻ERCC1⁺ cells.

Conclusion

High TOP2A expression or low RRM1 expression could predict the sensitivity of NMIBC to pirarubicin or gemcitabine treatment. HER2 and ERCC1 expression may affect the effect of TOP2A and RRM1, thus affecting the efficacy of chemotherapeutic drugs.

Platycodon D-induced A549 cell apoptosis through RRM1-regulated p53/VEGF/MMP2 pathway

BACKGROUND

Lung cancer is one of the leading causes of cancer-related deaths worldwide. Platycodin D (PD), a major pharmacological constituent from the Chinese medicinal herb named Platycodonis Radix, has shown potent anti-tumor activity. Also, it is also reported that PD could inhibit cellular growth in the non-small-cell lung carcinoma (NSCLC) A549 cell line. However, the underlying mechanism is not fully clarified.

METHODS

Cell proliferation was measured by MTT assay. Annexin V and propidium iodide (PI) assay were employed to study the apoptosis effects of PD on A549 cells. Western blot analysis was used to evaluate protein expression. Also, we used a siRNA against p53, as well as a plasmid-based RRM1 over-expression to investigate their functions.

RESULTS

It demonstrated PD inhibited A549 cell proliferation in a dose- and time-dependent manner. Further investigations showed that PD induced cell apoptosis, which was supported by dose-dependent and time-dependent caspase-3 activation and p53/VEGF/MMP2 pathway regulation. Also, PD demonstrated the inhibition effect of ribonucleotide reductase M1 (RRM1), whose role in various tumors is contradictory. Remarkably, in this work, RRM1 overexpression in A549 cells could have a negative impact on the regulation of the p53/VEGF/MMP2 pathway induced by PD treatment. Note as well that RRM1 overexpression also attenuated cell apoptosis and inhibition of cell proliferation of A549 treated with PD.

CONCLUSION

The results suggested that PD could inhibit A549 cell proliferation and induce cell apoptosis by regulating p53/VEGF/MMP2 pathway, in which RRM1 plays an important role directly.

Berberine inhibits non-small cell lung cancer cell growth through repressing DNA repair and replication rather than through apoptosis

At present, there are still many problems in the treatment of lung cancer, such as high cost, side effects and low quality of life. The advantages of traditional Chinese medicine (TCM) in the treatment of lung cancer are reflected. Berberine has been increasingly popular in colorectal cancer treatment, but little is known about its bioactivity against non-small cell lung cancer (NSCLC). Cell proliferation, cell apoptosis, cDNA microarray, gene and protein expression, and NSCLC transplanted tumour growth were performed. Berberine suppressed NSCLC cell proliferation and colony formation in vitro and inhibited NSCLC tumour growth in subcutaneously transplanted tumour lung tumour models, leading to prolonged survival of tumour-bearing mice. However, berberine did not induce the cleavage of Caspase 3 and PARP1, and could not induce apoptosis in all NSCLC cells. Moreover, 646 genes were differentially expressed upon berberine administration, which were involved in seven signal pathways, such as DNA replication. In cDNA microarray, berberine downregulated the expression of RRM1, RRM2, LIG1, POLE2 that involving DNA repair and replication. Our findings demonstrate that berberine inhibits NSCLC cells growth through repressing DNA repair and replication rather than through apoptosis. Berberine could be used as a promising therapeutic candidate for NSCLC patients.

RRM1 and ERCC1 as biomarkers in patients with locally advanced and metastatic malignant pleural mesothelioma treated with continuous infusion of low-dose gemcitabine plus cisplatin

BACKGROUND

Malignant Pleural Mesothelioma (MPM) is a rare but aggressive neoplasia that usually presents at advanced stages. Even though some advances have been achieved in the management of patients with MPM, this malignancy continuous to impose a deleterious prognosis for affected patients (12-18 months as median survival, and 5-10% 5-year survival rate), accordingly, the recognition of biomarkers that allow us to select the most appropriate therapy are necessary.

METHODS

Immunohistochemistry semi-quantitative analysis was performed to evaluate four different biomarkers (ERCC1, RRM1, RRM2, and hENT-1) with the intent to explore if any of them was useful to predict response to treatment with continuous infusion gemcitabine plus cisplatin. Tissue biopsies from patients with locally advanced or metastatic MPM were analyzed to quantitatively asses the aforementioned biomarkers. Every included patient received treatment with low-dose gemcitabine (250 mg/m²) in a 6-h continuous infusion plus cisplatin 35 mg/m² on days 1 and 8 every 3 weeks as first-line therapy.

RESULTS

From the 70 eligible patients, the mean and standard deviation (SD) for ERCC1, RRM1, RRM2 and hENT-1 were 286,178.3 (± 219, 019.8); 104,647.1 (± 65, 773.4); 4536.5 (± 5, 521.3); and 2458.7 (± 4, 983.4), respectively. Patients with high expression of RRM1 had an increased median PFS compared with those with lower expression (9.5 vs 4.8 months, p = < 0.001). Furthermore, high expression of RRM1 and ERCC1 were associated with an increased median OS compared with their lower expression counterparts; [(23.1 vs 7.2 months for RRM1 p = < 0.001) and (17.4 vs 9.8 months for ERCC1 p = 0.018)].

CONCLUSIONS

ERCC1 and RRM1 are useful biomarkers that predict better survival outcomes in patients with advanced MPM treated with continuous infusion of gemcitabine plus cisplatin.

FVE promotes RNA-directed DNA methylation by facilitating the association of RNA polymerase V with chromatin

Association of RNA polymerase V (Pol V) with chromatin is a critical step for RNA- directed DNA methylation (RdDM) in plants. Although the methylated DNA-binding proteins SUVH2 and SUVH9 and the chromatin remodeler-containing complex DRD1-DMS3-RDM1 are known to be required for the association of Pol V with chromatin, the molecular mechanisms underlying the association of Pol V with different chromatin environments remain largely unknown. Here we found that SUVH9 interacts with FVE, a homolog of the mammalian retinoblastoma-associated protein, which has been previously identified as a shared subunit of the histone deacetylase complex and the polycomb-type histone H3K27 trimethyltransferase complex. We demonstrated that FVE facilitates the association of Pol V with chromatin and thus contributes to DNA methylation at a substantial subset of RdDM target loci. Compared with FVE-independent RdDM target loci, FVE-dependent RdDM target loci are more abundant in gene-rich chromosome arms than in pericentromeric heterochromatin regions. This study contributes to our understanding of how the association of Pol V with chromatin is regulated in different chromatin environments.

Knockdown of RRM1 with Adenoviral shRNA Vectors to Inhibit Tumor Cell Viability and Increase Chemotherapeutic Sensitivity to Gemcitabine in Bladder Cancer Cells

RRM1-an important DNA replication/repair enzyme-is the primary molecular gemcitabine (GEM) target. High RRM1-expression associates with gemcitabine-resistance in various cancers and RRM1 inhibition may provide novel cancer treatment approaches. Our study elucidates how RRM1 inhibition affects cancer cell proliferation and influences gemcitabine-resistant bladder cancer cells. Of nine bladder cancer cell lines investigated, two RRM1 highly expressed cells, 253J and RT112, were selected for further experimentation. An RRM1-targeting shRNA was cloned into adenoviral vector, Ad-shRRM1. Gene and protein expression were investigated using real-time PCR and western blotting. Cell proliferation rate and chemotherapeutic sensitivity to GEM were assessed by MTT assay. A human tumor xenograft model was prepared by implanting RRM1 highly expressed tumors, derived from RT112 cells, in nude mice. Infection with Ad-shRRM1 effectively downregulated RRM1 expression, significantly inhibiting cell growth in both RRM1 highly expressed tumor cells. In vivo, Ad-shRRM1 treatment had pronounced antitumor effects against RRM1 highly expressed tumor xenografts (p < 0.05). Moreover, combination of Ad-shRRM1 and GEM inhibited cell proliferation in both cell lines significantly more than either treatment individually. Cancer gene therapy using anti-RRM1 shRNA has pronounced antitumor effects against RRM1 highly expressed tumors, and RRM1 inhibition specifically increases bladder cancer cell GEM-sensitivity. Ad-shRRM1/GEM combination therapy may offer new treatment options for patients with GEM-resistant bladder tumors.

Individualized chemotherapy guided by the expression of ERCC1, RRM1, TUBB3, TYMS and TOP2A genes versus classic chemotherapy in the treatment of breast cancer: A comparative effectiveness study

ERCC1, RRM1, TUBB3, TYMS and TOP2A genes have been shown to be associated with drug resistance in various types of tumors; however, their roles in breast cancer chemotherapy have not been fully validated. In the present study, 140 well-matched patients with breast cancer, comprising 70 patients receiving individualized chemotherapy and 70 receiving classic chemotherapy, were analyzed. In the individualized chemotherapy group, the mRNA expression levels of ERCC1, RRM1, TUBB3, TYMS and TOP2A in breast cancer tissues were measured using multiplex branched DNA liquidchip technology prior to chemotherapy; an individualized chemotherapy regimen was developed for each patient according to the results. As a control, patients in the classic chemotherapy group received a docetaxel + epirubicin + cyclophosphamide regimen. Survival analyses were performed using the Kaplan-Meier method. The prognostic factors for disease-free survival (DFS) and overall survival (OS) in the patients were identified via Cox's proportional hazards regression model. Adverse reactions were evaluated according to the National Cancer Institute Common Toxicity Criteria 4. Compared with the classic chemotherapy group, the DFS and OS of the individualized chemotherapy group were significantly longer (DFS, 77.4 vs. 67.1 months, P=0.039; OS, 81.4 vs. 75.4 months, P=0.031), and the incidence of grade 2 or 3 palpitations and chest tightness was lower (12.9 vs. 27.1%, P=0.035). The chemotherapy strategy guided by genetic detection was an independent protection factor for DFS [hazard ratio (HR)=0.389, 95% confidence interval (CI): 0.153, 0.989, P=0.047], but not an independent protection factor for OS (HR=0.340, 95% CI: 0.107, 1.078, P=0.067). The results indicate that the combined detection of ERCC1, RRM1, TUBB3, TYMS and TOP2A gene expression and use of the results to guide individualized chemotherapy can improve treatment efficacy and reduce unnecessary toxicity.

Exosome-Mediated Transfer of Long Noncoding RNA HOTAIR Regulates Temozolomide Resistance by miR-519a-3p/RRM1 Axis in Glioblastoma

Background: Chemoresistance obstructs the treatment of glioblastoma (GB). Exosome-mediated transfer of long noncoding RNAs (lncRNAs) was reported to regulate chemoresistance in diverse cancers. The authors aimed to investigate the underlying mechanism of lncRNA HOX transcript antisense intergenic RNA (HOTAIR) in regulating temozolomide (TMZ) resistance in GB. Materials and Methods: 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was utilized to check TMZ resistance and cell proliferation. The abilities of cell migration and invasion were evaluated by transwell assay. The protein levels of E-cadherin, N-cadherin, Vimentin, CD63, CD81, and ribonucleoside-diphosphate reductase subunit M1 (RRM1) were measured by western blot. Quantitative real-time polymerase chain reaction was conducted to detect the levels of HOTAIR, microRNA (miR)-519a-3p, and RRM1. The starBase was hired to predict the target sites between miR-519a-3p and HOTAIR or RRM1 and the dual-luciferase reporter assay was performed to verify the interaction. Xenograft tumor model was established to investigate the biological role of HOTAIR in vivo. Results: The high abilities of cell viability and metastasis were observed in TMZ-resistant GB cells. LncRNA HOTAIR was significantly upregulated in TMZ-resistant GB cells and its downregulation inhibited proliferation, migration, invasion, and epithelial/mesenchymal transition in TMZ-resistant GB cells. Further analysis indicated that exosomal lncRNA HOTAIR induced TMZ resistance and modulated TMZ resistance through miR-519a-3p/RRM1 axis. Besides, serum exosomal lncRNA HOTAIR was stable and had diagnostic value. Moreover, knockdown of lncRNA HOTAIR reduced TMZ resistance in vivo. Conclusions: Exosomal lncRNA HOTAIR mediated TMZ resistance through miR-519a-3p/RRM1 axis in GB.

LINC02535 co-functions with PCBP2 to regulate DNA damage repair in cervical cancer by stabilizing RRM1 mRNA

Cervical cancer (CC) is one of the commonest malignant cancers among women with high morbidity and mortality. Despite encouraging advances had been found in diagnostic and therapeutic strategies, effective therapeutic strategy and further exploration of the mechanism underlying in CC is still needed. We searched The Cancer Genome Atlas database and found that long noncoding RNA LINC02535 was highly expressed in CC. LINC02535 has not been studied in CC, and its molecular regulation mechanism remains unknown. Based on starBase database, LINC02535 could potentially bind poly (rC) binding protein 2 (PCBP2). In the present study, we discovered a significant increase of the LINC02535 and PCBP2 expression in CC tissues and cells as compared with the adjacent normal tissues and normal cervical epithelial cells. LINC02535 and PCBP2 can bind with each other and were colocated in cytoplasm. LINC02535 and PCBP2 promoted cell proliferation, migration, invasion, and suppressed apoptosis in CC. LINC02535 and PCBP2 facilitated the repair of DNA damage to promote CC progression. LINC02535 cooperated with PCBP2 to enhance the stability of RRM1 messenger RNA (mRNA). RRM1 promoted the repair of DNA damage and epithelial-to-mesenchymal transition (EMT) process in CC cells. LINC02535 regulated tumorigenesis in vivo. In conclusion, LINC02535 cooperated with PCBP2, regulated stability of RRM1 mRNA to promote cell proliferation and EMT process in CC cells by facilitating the repair of DNA damage, providing a potential biomarker for CC.

Messenger-RNA Expression of Five Gemcitabine Sensitivity-related Genes Predicting Outcome in Advanced-stage Non-small Cell Lung Cancer

BACKGROUND/AIM

Tumoural transcriptional levels of RRM1, RRM2, CDA, dCK and hENT1 genes are potential biomarkers for gemcitabine's efficacy in non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

We retrospectively analysed each gene's relative mRNA expression by quantitative, real-time polymerase chain reaction in microdissected, formalin-fixed, paraffin-embedded primary-tumour specimens from 219 chemonaïve patients with advanced-stage NSCLC, treated with gemcitabine-based regimens within clinical trials. The five genes' transcriptional patterns were integrated into an ordinal, five-level gemcitabine-susceptibility classifier (5L-GSC).

RESULTS

Treatment efficacy increased progressively across the five susceptibility levels, with the very-high chemosensitivity cases obtaining the most clinical benefit. 5L-GSC emerged as an independent prognosticator for overall response and disease control rates, time to progression and overall survival at p-values of 0.03, 0.004, <0.001 and <0.001, respectively, with results remaining significant after bootstrapping. Penalised, optimally-scaled, categorical-regression modelling of overall response identified 5L-GSC as the most stable predictor.

CONCLUSION

The proposed composite biomarker is promising for customising front-line chemotherapy in NSCLC.

Cancer Fighting SiRNA-RRM2 Loaded Nanorobots

BACKGROUND

Silencing of several genes is critical for cancer therapy. These genes may be apoptotic gene, cell proliferation gene, DNA synthesis gene, etc. The two subunits of Ribonucleotide Reductase (RR), RRM1 and RRM2, are critical for DNA synthesis. Hence, targeting the blockage of DNA synthesis at tumor site can be a smart mode of cancer therapy. Specific targeting of blockage of RRM2 is done effectively by SiRNA. The drawbacks of siRNA delivery in the body include the poor uptake by all kinds of cells, questionable stability under physiological condition, non-target effect and ability to trigger the immune response. These obstacles may be overcome by target delivery of siRNA at the tumor site. This review presents a holistic overview regarding the role of RRM2 in controlling cancer progression. The nanoparticles are more effective due to specific characteristics like cell membrane penetration capacity, less toxicity, etc. RRM2 have been found to be elevated in different types of cancer and identified as the prognostic and predictive marker of the disease. Reductase RRM1 and RRM2 regulate the protein and gene expression of E2F, which is critical for protein expression and progression of cell cycle and cancer. The knockdown of RRM2 leads to apoptosis via Bcl2 in cancer. Both Bcl2 and E2F are critical in the progression of cancer, hence a gene that can affect both in regulating DNA replication is essential for cancer therapy.

AIM

The aim of the review is to identify the related gene whose silencing may inhibit cancer progression.

CONCLUSION

In this review, we illuminate the critical link between RRM-E2F, RRM-Bcl2, RRM-HDAC for the therapy of cancer. Altogether, this review presents an overview of all types of SiRNA targeted for cancer therapy with special emphasis on RRM2 for controlling the tumor progression.

Identification of chemoresistance-related mRNAs based on gemcitabine-resistant pancreatic cancer cell lines

Gemcitabine (GEM) alone and GEM-based chemotherapy are the preferred regimens for treating advanced unresectable and metastatic pancreatic cancer (PC). However, these treatments have limited efficacy due to acquired resistance of cancer cells to chemotherapy, the mechanisms of which are not fully understood. In this study, we established two stable multidrug-resistant cell lines, BxPC-3-GR and CFPAC-1-GR, from their corresponding parental cells through exposure to GEM following a stepwise incremental dosing strategy. The GEM IC₅₀ values of BxPC-3-GR and CFPAC-1-GR increased 112-fold and 210-fold, respectively, compared to parental cell lines. In vitro and in vivo experiments confirmed that both GEM-resistant cell subgroups declined in proliferative capacity, but were more resistant to GEM. Unlike CFPAC-1-GR, BxPC-3-GR exhibited enhanced migratory and invasive properties compared with BxPC-3 in vitro. We also compared differentially expressed mRNA profiles between parental and GEM-resistant cells using transcriptome sequencing. RRM1, STIM1, and TRIM21 were significantly upregulated in both GEM-resistant cell lines and confirmed to be associated with the degree of GEM resistance by quantitative reverse-transcription polymerase chain reaction and western blot analysis. These three genes were more highly expressed in PC tissues and potentially regarded as prognostic biomarkers through database mining. Thus, our findings provide chemo-resistant cell models to better understand the underlying mechanisms of chemoresistance, and to explore potential biomarkers for GEM response in PC patients.

RRM1 predicts clinical outcome of high-and intermediate-risk non-muscle-invasive bladder cancer patients treated with intravesical gemcitabine monotherapy

Background

The expression level of ribonucleotide reductase subunit M1 (RRM1) is closely related to the effect of gemcitabine-based therapy in advanced bladder cancer. However, the value of RRM1 expression in predicting progression-free survival in non-muscle-invasive bladder cancer (NMIBC) patients treated with intravesical gemcitabine chemotherapy has not been elucidated.

Methods

This study randomly assigned 162 patients to either the RRM1-known group or the unknown group. We collected cancer tissues from 81 patients to evaluate the mRNA expression of RRM1 by using liquid chip technology. All patients were diagnosed and then treated with intravesical gemcitabine monotherapy immediately after transurethral resection of the bladder tumour (TURBT).

Results

RRM1 expression was high in 21% (17/81) of patients. The RRM1 mRNA level was not correlated with sex, age, weight, performance status, or CUA/EAU risk (p > 0.05). Progression-free survival (PFS) was significantly longer for patients with low RRM1 expression than for patients with high and unknown RRM1 expression (p = 0.009). Additionally, the 1- and 2-year relapse rates also differed according to RRM1 expression level. The 1-year relapse rates for RRM1-low, RRM1-high and RRM1-unknown patients were 0, 17.7 and 6.2% (p = 0.009), while the 2-year relapse rates for these groups were 3.1, 29.4, and 11.1% (p = 0.005), respectively.

Conclusions

This preliminary study showed that low RRM1 expression was associated with longer progression-free survival and lower 1-year/2-year relapse rates in NMIBC patients treated with intravesical gemcitabine monotherapy, despite the need for further verification with large sample sizes and considering more mixed factors and biases.

High Glucose Triggers Nucleotide Imbalance through O-GlcNAcylation of Key Enzymes and Induces KRAS Mutation in Pancreatic Cells

KRAS mutations are the earliest events found in approximately 90% of pancreatic ductal adenocarcinomas (PDACs). However, little is known as to why KRAS mutations preferentially occur in PDACs and what processes/factors generate these mutations. While abnormal carbohydrate metabolism is associated with a high risk of pancreatic cancer, it remains elusive whether a direct relationship between KRAS mutations and sugar metabolism exists. Here, we show that under high-glucose conditions, cellular O-GlcNAcylation is significantly elevated in pancreatic cells that exhibit lower phosphofructokinase (PFK) activity than other cell types. This post-translational modification specifically compromises the ribonucleotide reductase (RNR) activity, leading to deficiency in dNTP pools, genomic DNA alterations with KRAS mutations, and cellular transformation. These results establish a mechanistic link between a perturbed sugar metabolism and genomic instability that induces de novo oncogenic KRAS mutations preferentially in pancreatic cells.

KRAS mutation and DNA repair and synthesis genes in non-small-cell lung cancer

The aim of the present study was to assess the expression of select DNA repair and synthesis genes in non-small-cell lung cancer (NSCLC) according to KRAS mutation status. ERCC1, TS, RRM1, and BRCA1 mRNA expression levels were assessed from either primary or metastatic tumor specimens of patients diagnosed with epidermal growth factor receptor (EGFR) wild-type (WT) advanced NSCLC. Total RNA was isolated from paraffin-embedded tumor specimens using the RNeasy FFPE kit and automatically purified using a QiaCube instrument. Quantification levels were analyzed by real-time one-step RT-PCR using QuantiFast technology, and the results were compared considering β-actin as the internal reference gene. One hundred and eighty-four patients with advanced NSCLC were evaluated for the analysis, of which 92 were KRAS-mutants. Nearly all patients had adenocarcinoma histology (96.7%). Among KRAS-mutants, the majority had a KRAS codon 12 mutation (88%), the most common being G12C (44.4% of cases). Mean ERCC1 levels were indicated to be significantly higher in KRAS-mutants when compared with KRAS WT patients (3,234±6.63 vs. 184±1.24; P=0.05). However, mean TS levels were significantly lower in the KRAS-mutant subgroup compared with the KRAS WT subgroup (4,481±3.756 vs. 5,941±6.4; P=0.039). KRAS-mutant NSCLCs are more likely to express high ERCC1 and low TS levels. This finding may suggest different sensitivity to cytotoxic chemotherapy according to KRAS mutation status.

RRM1 expression and the clinicopathological characteristics of patients with non-small cell lung cancer treated with gemcitabine

Background

The usefulness of ribonucleotide reductase catalytic subunit M1 (RRM1) for predicting the therapeutic effects of gemcitabine-containing chemotherapy in patients with non-small cell lung cancer (NSCLC) remains controversial. RRM1-positive patients show unique clinicopathological features.

Methods

Here, we performed a meta-analysis to systematically evaluate the relationship between RRM1 expression and the clinicopathological characteristics of NSCLC patients treated with gemcitabine-containing regimens. A comprehensive electronic and manual search was performed to identify relevant articles. The pooled relative risk (RR) and 95% CI were used to estimate the relation between the clinicopathological characteristics of NSCLC patients and RRM1 expression.

Results

The study included 31 observational studies and 3,667 patients. The analysis showed no significant association between RRM1 expression and pathological type, stage, and smoking status; however, RRM1 positivity was significantly lower in women than in men (43.0% vs 51.7%, RR=0.84, 95% CI: 0.74-0.94, P=0.004).

Conclusion

The present pooled analyses demonstrated that RRM1 positivity in women with advanced NSCLC was associated with a higher rate of response to gemcitabine-containing regimens. Immunohistochemistry may be valuable to prescreen for RRM1 expression in clinical practice, whereas PCR can be routinely used as a verification method. These findings will help design suitable molecular-targeted therapies for NSCLC.

Adjuvant Therapy of Resected Non-small Cell Lung Cancer: can We Move Forward?

OPINION STATEMENT

Twenty years ago, an individual patient data meta-analysis of eight cisplatin-based adjuvant chemotherapy (AC) studies in completely resected early stage non-small cell lung cancer (NSCLC) demonstrated a 13 % reduction of the risk of death favoring chemotherapy that was of borderline statistical significance (p = 0.08). This marginal benefit boosted a new generation of randomized trials to evaluate the role of modern platinum-based regimens in resectable stages of NSCLC and, although individual studies generated conflicting results, overall they contributed to confirm the role of AC which is now recommended for completely resected stage II and III NSCLC, mostly 4 cycles, while subset analyses suggested a benefit in patients with large IB tumors. Cisplatin-based therapy was the core regimen of those adjuvant clinical trials and even if a substitution with other platinum-derived was also suggested, mainly based on extrapolated data from studies in advanced disease, cisplatin was confirmed to be slightly superior to carboplatin and is still the drug of choice in the adjuvant setting. Currently, any attempt to improve efficacy of cisplatin-based chemotherapy through antiangiogenic drugs association or pharmacogenomics approaches have failed, while results of additional studies are eagerly awaited. In the context of promising targeted therapies, even if several randomized trials in the advanced setting evaluated tyrosine kinase inhibitors (TKis) versus platinum-based chemotherapy and showed impressive results, clinical experience with TKIs in the adjuvant setting is still limited and most of the trials have not required patients to be molecularly tested for the drug-specific molecular predictive factor. At the present time, the role of targeted agents as adjuvant approaches remains largely not investigated. Finally, with the negative experience of the use of vaccines in this setting, the integration of immunotherapy (mainly immunocheckpoint inhibitors) in platinum-based schedules has just started to be evaluated, representing a potential future clinical option, but still far from clinical practice.

MicroRNA-1468-5p inhibits glioma cell proliferation and induces cell cycle arrest by targeting RRM1

MicroRNAs are associated with different types of cancers. In this study, we found that miR-1468-5p could inhibit growth and cell cycle progression in glioma by targeting ribonucleotide reductase large subunit M1 (RRM1). First, we analyzed miR-1468-5p expression in different glioma grades and the prognostic significance of its expression in glioblastoma multiform patients from the Chinese Glioma Genome Atlas. Then, we expressed miR-1468-5p in U87 and U251 cells and assessed the effects on proliferation and cell cycle progression using cell counting kit-8, colony formation, EdU and flow cytometry assays. Western blotting and luciferase reporter assays identified RRM1 as a novel direct target of miR-1468-5p. Experiments to determine the role of RRM1 in glioma showed that RRM1 expression was significantly higher in glioma than in normal brain tissues, and silencing RRM1 with small-interfering RNAs decreased proliferation and suppressed cell cycle progression, which indicated that RRM1 had pro-tumor functions. miR-1468-5p overexpression suppressed RRM1 expression, reduced glioma cell proliferation and induced cell cycle arrest, which was partially rescued by forced RRM1 expression. In summary, our study revealed that the regulatory mechanism of miR-1468-5p in glioma cell cycle progression involved direct regulation of RRM1 expression, suggesting that RRM1 may be a potential therapeutic target for glioma.

RRM1, RRM2 and ERCC2 Gene Polymorphisms in Coronary Artery Disease

BACKGROUND/AIM

Coronary artery disease (CAD) is a chronic inflammatory disease seen as formation of atherosclerotic plaques (atheroma) in coronary arteries. Recent published papers show that DNA damage and repair mechanisms play a crucial role on the development and severity of atheromas. In this study, we investigated nucleotide excision repair (NER) pathway-related gene polymorphisms in atherosclerosis. XPD, encoded by ERCC2 gene, is an ATP-depended helicase enzyme involved in the NER pathway. Ribonucleotide reductase (RR) is a tetra meric enzyme, synthesizing deoxyribonucleotides from ribonucleotides for DNA synthesis. RR is encoded by the RRM1 and RRM2 genes, which are two subunits of RR enzyme.

MATERIALS AND METHODS

DNA samples isolated from peripheral blood were genotyped with real-time polymerase chain reaction (RT-PCR) for RRM1 (rs12806698), RRM2(rs6859180) and ERCC2 (rs13181) genes.

RESULTS

The frequency of the RRM1 AC heterozygote genotype was found to be significantly lower (odds ratio (OR)=0.369, 95% confidence interval (CI)=0.179-0.760; p=0.006), whereas the CC homozygote genotype was found to be significantly higher in patients compared to controls (OR=7.636, 95% CI=2.747-21.229; p=0.000). In addition, the RRM1 A allele was higher in control group (p=0.000, OR=0.131 95%CI=0.047-0.364). For the ERCC2 gene, GG genotype was significantly higher in control group (p=0.017, OR=0.387, 95%CI=0.175-0.152) and TT genotype (p=0.021) was higher in CAD group. TT genotype had a ~3-fold increased risk (OR=3.615, 95%CI=1.148-11.380) for CAD. Carrying T allele appears to be a risk factor for CAD (p=0.017, OR=2.586, 95%CI=1.173-5.699), while the G allele might be a risk-reducing factor (p=0.021, OR=0.277, 95%CI=0.088-0.871) for CAD.

CONCLUSION

RRM1 and ERCC gene polymorphisms, having homozygous mutant genotype, might be a risk factor for CAD. RRM1 and ERCC wild type alleles are risk-reducing factor for CAD. Also, carrying RRM1 A allele might have a protective effect for smokers.

Combined analysis of rearrangement of ALK, ROS1, somatic mutation of EGFR, KRAS, BRAF, PIK3CA, and mRNA expression of ERCC1, TYMS, RRM1, TUBB3, EGFR in patients with non-small cell lung cancer and their clinical significance

PURPOSE

The assessment of single gene such as ERCC1, TYMS, RRM1, TUBB3, EGFR, KRAS, BRAF, PIK3CA, ALK, and ROS1 is now widely applied in therapeutic decisions of non-small cell lung cancer (NSCLC). The aim of our study was to concurrently analyze these genes and evaluate their clinical significance in patients with NSCLC.

METHODS

Rearrangement of ALK and ROS1 was analyzed in 120 patients using FISH assays. Somatic mutation of EGFR, KRAS, BRAF, PIK3CA and mRNA expression of ERCC1, TYMS, RRM1, TUBB3, EGFR were examined by liquidchip platform in 350 patients . Data on clinical features were obtained from medical records of 119 patients, and the follow-up was conducted in 106 patients who received platinum-based adjuvant chemotherapy.

RESULTS

We identified 5.0% ALK rearrangements, 1.7% ROS1 rearrangements, 36.6% EGFR mutations, 8.9% KRAS mutations, 0% BRAF mutations, and 4.0% PIK3CA mutations. Double or coexisting mutations were identified in 13 patients. Significant correlations were observed among EGFR, KRAS mutation, ERCC1, TYMS, RRM1, TUBB3, EGFR expression, and clinical features, especially histology (P < 0.05). Significant cross-correlations were observed in some pairs of genes (P < 0.05). Patients with low RRM1 expression had a better progression-free survival (PFS) (P < 0.05). Furthermore, EGFR-mutated patients with low RRM1 expression or patients with both ERCC1 and RRM1 low expression had a better PFS (P < 0.05).

CONCLUSION

Combined analysis of these commonly studied genes may promote the individual treatment in NSCLC. RRM1 may be a prognostic and predictive biomarker for PFS in patients with NSCLC who received platinum-based adjuvant chemotherapy, and combining EGFR mutation and RRM1 expression or combining ERCC1 and RRM1 expression can enhance prognostic and predictive power for PFS.

A randomized phase II trial of ERCC1 and RRM1 mRNA expression-based chemotherapy versus docetaxel/carboplatin in advanced non-small cell lung cancer

OBJECTIVES

To evaluate whether the selection of first-line chemotherapy based on ERCC1 and RRM1 mRNA expression levels would improve clinical outcomes in advanced non-small cell lung cancer (NSCLC) patients.

MATERIALS AND METHODS

Eligible patients were randomly assigned 1:1 to the experimental and control arms; the experimental arm received gemcitabine/carboplatin (GC) if ERCC1 and RRM1 expression was low, gemcitabine/vinorelbine (GV) if ERCC1 was high and RRM1 was low, docetaxel/carboplatin (DC) if ERCC1 was low and RRM1 was high, and docetaxel/vinorelbine (DV) if both were high. In the control arm, patients received DC.

RESULTS

This study was prematurely terminated after the futility analysis of 43 progression-free survival (PFS) events. A total of 55 patients (n = 26 in the experimental arm, n = 29 in the control arm) were evaluable for efficacy and toxicity. Nineteen (73.1%) patients were assigned to receive GC, 0 (0.0%) to GV, 4 (15.4%) to DC, and 3 (11.5%) to DV in the experimental arm. The overall response rates were 42.3 and 48.3% in the experimental and control arms, respectively, which were not statistically different (P = 0.657). The median PFS was 5.2 months in the experimental arm and 5.4 months in the control arm (P = 0.286). The median overall survival was 17.4 months in the experimental arm and 12.6 months in the control arm (P = 0.638). The occurrence of grade 3 or higher neutropenia (69.2 vs. 93.1%, P = 0.035) and febrile neutropenia (3.8 vs. 24.1%, P = 0.054) was more common in the control arm.

CONCLUSION

ERCC1 and RRM1 mRNA expression-based chemotherapy did not improve clinical outcomes in advanced NSCLC (NCT01648517).

The relationship between RRM1 gene polymorphisms and effectiveness of gemcitabine-based first-line chemotherapy in advanced NSCLC patient

Purpose

Chemotherapy with platinum compounds and gemcitabine is frequently used in first-line treatment of advanced non-small cell lung cancer (NSCLC) patients in which tyrosine kinase inhibitors (EGFR or ALK) cannot be administered. Unfortunately, less than half of the patients achieve the benefit from chemotherapy. Gemcitabine is an analog of deoxycytidine (pyrimidine antimetabolite) with antitumor activity. The excess of deoxycytidine synthesized by RRM1 enzyme activity may be a cause of competitive displacement of gemcitabine, which reduces the efficacy of this cytostatic. The aim of this study was to determine the association between single nucleotide polymorphisms (SNPs) of the RRM1 promoter (−37C>A, −524C>T) and the effectiveness of first-line chemotherapy based on platinum compounds and gemcitabine in NSCLC patients.

Patients and methods

SNPs were determined by SNaPshot PCR^® in DNA isolated from peripheral blood of 91 NSCLC patients.

Results

The median progression-free survival (PFS) was significantly longer in carriers of AA (−37C>A) as well as CC (−524C>T) genotype of RRM1 compared to patients with other genotypes (10.5 vs 3.5 months, p = 0.0437; HR = 2.17, 95 % CI 1.02–4.62 and 10.5 vs 3.5 months, p = 0.0343; HR = 2.12, 95 % CI 1.06–4.27). In addition, the CC genotype carriers (−37C>A) showed a significant increase in the risk of shortening overall survival (OS) in comparison to patients with AA or AC genotypes (9.5 vs 18 months, p = 0.0193; HR = 2.13, 95 % CI 1.13–4.03).

Conclusions

Presence of rare AA (−37C>A) and CC (−524C>T) genotypes of the RRM1 may be favorable predictive factors for chemotherapy with platinum compounds and gemcitabine in NSCLC patients.

RRM1, ERCC1 and TS1 Immunofluorescence Expression in Leiomyosarcoma: A Tissue Microarray Study with Clinical Outcome Correlation Analysis

ERCC1, RRM1 and TS1 are reportedly linked to chemotherapy resistance in lung and other cancers. However, there are currently no studies reporting the relationship between these genes and clinical parameters in leiomyosarcomas.

METHOD

This study investigated the expression pattern of ERCC1, RRM1 and TS1 in forty-four leiomyosarcoma samples by the use of tissue microarray (TMA), immunofluorescence and AQUA methods. The results were then analyzed for expression level and correlations were made with clinical outcome to determine their potential prognostic value in leiomyosarcoma.

RESULTS

In the forty-four samples studied, the expression level of these three proteins can be well quantified in the AQUA system and reflected by the AQUA score. RRM1 and ERCC1 expression levels did not show any relationship with overall survival. However, a correlation was found between TS1 expression in the cytoplasm and overall survival. The high expression group had a shorter overall survival time (log-rank p = 0.0498). This trend was confirmed by the Cox proportional hazards model.

DISCUSSION

The poor overall survival of leiomyosarcoma is linked to TS1 cytoplasm expression which may be useful in predicting prognoses of this tumor, methods targeting expression of TS1 may lead to improved overall survival in leiomyosarcoma, though more detailed information regarding treatment information and a larger sample size is needed to confirm this phenomenon.

Therapeutic approach guided by genetic alteration: use of MTOR inhibitor in renal medullary carcinoma with loss of PTEN expression

Renal Medullary Cancer (RMC) is a rare and aggressive type of renal cell cancer that presents predominantly in patients with sickle cell hemoglobinopathies, and is typically metastatic at the time of presentation. Although platinum based chemotherapeutic regimens have recently emerged as the best option for producing a clinically significant response as reported in various case series, the response is far from satisfactory, as most RMC patients still succumb to their disease within a year of diagnosis. There is currently no standard of care for treatment of this disease. We report, to our knowledge, the first case of RMC where in molecular characterization of the tumor was used to guide therapy. In our patient, molecular analysis identified a decreased expression of Ribonucleotide Reductase M1(RRM1) and phosphatase and tensin homolog (PTEN). Based on these results of PTEN deficiency, we started our patient on everolimus (an MTOR inhibitor) maintenance after treating him with an induction chemotherapy regimen of Paclitaxel-Cisplatin-Gemcitabine (PCG). His tumor responded to induction therapy and he went into complete remission and remained in remission for 7 months. He is now alive about 14 months from his diagnosis and is asymptomatic with minimal disease. The rarity of RMC makes it very difficult to do any meaningful clinical trials in this group of patients. The overall prognosis for RMC remains very poor and knowledge about driver mutations may help in guiding therapy to improve survival in this select group of patients, where there is dearth of available therapies.

Prognostic value of ERCC1, RRM1, BRCA1 and SETDB1 in early stage of non-small cell lung cancer

INTRODUCTION

Nowadays, 40 % of early-stage NSCLC patients relapse in the 2 years following resection, suggesting a mis-staging in this group of patients who are not receiving adjuvant chemotherapy. Although different biomarkers, such as ERCC1, RRM1 and BRCA1 have been found to present prognostic value in advanced NSCLC patients, in early-stage NSCLC patients its relevance remains unclear. Moreover, SETDB1 has been recently proposed as a bona fide oncogene in lung tumourigenesis and related with metastasis. The aim of the present study was to analyze the prognostic value of ERCC1, RRM1, BRCA1 and SETDB1 expression levels in NSCLC patients at stage I.

PATIENTS AND METHODS

ERCC1, RRM1, BRCA1 and SETDB1 expression at mRNA level was analyzed by real-time quantitative RT-PCR in fresh-frozen tumor and normal adjacent lung tissue samples from 64 stage I NSCLC patients. Later, significant association between gene expression levels, clinicopathological characteristics and patient's disease-free survival was assessed.

RESULTS

We did not find any statistically significant correlation between gene expression and gender, age, histological type or smoking status. Univariate followed by multivariate Cox analysis showed that higher levels of BRCA1 and SETDB1 expression were significantly associated with shorter disease-free survival in stage I NSCLC patients.

CONCLUSION

Our study finds that ERCC1 and RRM1 are not independent prognostic factors of recurrence in stage I NSCLC patients. By contrast, BRCA1 and SETDB1 stand out as the most significant prognostic markers in this group of patients, appearing as promising tools to predict tumor recurrence in early-stage NSCLC patients.

(1)H, (15)N and (13)C chemical shift assignments of the La motif and RRM1 from human LARP6

We report here the nearly complete (1)H, (15)N and (13)C resonance assignment of the La motif and RNA recognition motif 1 of human LARP6, an RNA binding protein involved in regulating collagen synthesis.

Potent effect of adenoviral vector expressing short hairpin RNA targeting ribonucleotide reductase large subunit M1 on cell viability and chemotherapeutic sensitivity to gemcitabine in non-small cell lung cancer cells

BACKGROUND

Ribonucleotide reductase large subunit (RRM1) is the main enzyme responsible for synthesis of the deoxyribonucleotides used during DNA synthesis. It is also a cellular target for gemcitabine (GEM). Overexpression of RRM1 is reportedly associated with resistance to GEM and the poor prognosis for many types of malignant tumours. Aim of the present study is to establish gene therapy against RRM1-overexpressing tumours.

METHOD

An adenoviral vector that encoded a short hairpin siRNA targeting the RRM1 gene (Ad-shRRM1) was constructed. Two RRM1-overexpressing non-small cell lung cancer (NSCLC) lines, MAC10 and RERF-LC-MA, were used. Finally, a human tumour xenograft model in nude mice was prepared by subcutaneously implanting tumours derived from RERF-LC-MA cells.

RESULTS

Ad-shRRM1 effectively downregulated RRM1 mRNA and protein in both types of NSCLC cells and significantly reduced the percentage of viable cells as detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay (p<0.005). Caspase 3/7 analysis revealed that transfection with Ad-RRM1 increased the percentage of apoptotic cells in culture containing either type of RRM1-overexpressing cell (p<0.001). Treatment with Ad-shRRM1 exerted a potent antitumour effect against the RRM1-overexpressing RERF-LC-MA xenografts (p<0.05). Furthermore, Ad-shRRM1-mediated inhibition of RRM1 specifically increased sensitivity to gemcitabine of each type of RRM1-overexpressing tumour cell. Combination treatment with Ad-shRRM1 and GEM exerted significantly greater inhibition on cell proliferation than Ad-shRRM1 or GEM treatment alone.

CONCLUSION

RRM1 appeared to be a promising target for gene therapy, and Ad-shRRM1 had strong antitumour effects, specifically anti-proliferative and pro-apoptotic effects, against NSCLC cells that overexpressed RRM1. Combination therapy with Ad-shRRM1 and GEM may become a new treatment option for patients with NSCLC.

ERCC1 and RRM1 as a predictive parameter for non-small cell lung, ovarian or pancreas cancer treated with cisplatin and/or gemcitabine

Background

We aimed to investigate the impact of RRM1 and ERCC1 expression on response to cisplatin and/or gemcitabine chemotherapy in patients with lung, ovarian or pancreatic cancer.

Material and methods

Patients with lung, ovarian or pancreatic cancer, who used cisplatin and/or gemcitabine therapy were included; hospital files were examined and RRM1 and ERCC1 expression were evaluated with an immunohistochemical method on tissue cross sections from paraffin blocks of the tumour.

Results

Out of 89 patients, 51%, 30% and 19% had lung, ovarian and pancreatic cancer, respectively. The response rates to the therapy in patients with lung and ovarian cancer having low ERCC1 expression were 62% and 90%, respectively (p = 0.028 and p = 0.044, respectively). No significant association was found between ERCC1 expression and response to therapy in patients with pancreatic cancer (p = 0.354). Therapeutic response rates in patients with lung and pancreatic cancer with low RRM1 expression were 60% and 82%, respectively. Survival rates were higher in patients with lung cancer in which ERCC1 and RRM1 expressions were low. Median survival duration in patients with ovarian cancer showing low ERCC1 and RRM1 expressions was longer than that seen in patients with high expressions. Although no significant correlation was found between ERCC1 and the survival in ovarian cancer (p = 0.183), there was a significant correlation between RRM1 expression and survival in patients with pancreatic cancer (p = 0.005).

Conclusions

Our results suggest a predictive value of ERCC1 in lung and ovarian cancers, and also RRM1 in lung and pancreatic cancers.

Drug sensitivity profiling and molecular characteristics of cells from pleural effusions of patients with lung adenocarcinoma

We propose to assess the therapeutic value of biomarker-guided individualized chemotherapy in patients with metastasizing lung adenocarcinoma. In this study, we used primary cells from pleural effusions from sixteen patients diagnosed with adenocarcinomas originating in the lung and from four patients with no malignant diagnosis. The ex vivo drug sensitivity of primary cells was assessed for 32 chemotherapeutical drugs. Linear regression analyses were performed to examine possible correlations between the drug sensitivity, overall survival and expression of ERCC1 and RRM1. The ex vivo drug sensitivity profiles of the patients revealed considerable heterogeneity in drug response. Vinblastine, vinorelbine, paclitaxel and actinomycin D showed high efficiency against 50% of the tested primary cells. Significant correlation was detected between the ex vivo sensitivity to platinum based drugs and gemcitabine and the level of ERCC1 and RRM1. No significant correlation was however seen between overall survival and drug sensitivity. The heterogeneity of the drug response suggests that optimal care of the adenocarcinoma patients should include the determination of drug sensitivity of the primary cells and would benefit to use personalized therapy.

ERCC1, RRM1 and TUBB3 mRNA expression on the tumor response and overall survival of non-small cell lung cancer treated with platinum-based chemotherapy

Objective: We aimed to analyze the expression of ERCC1, RRM1 and TUBB3 in 305 patients with advanced non-small cell lung cancer (NSCLC) and investigate whether these genes can be used as biomarkers for predicting tumor response and clinical outcome.

Methods: Total 305 patients with unresectable and locally advanced NSCLC were collected between January 2007 and December 2008. cDNA of ERCC1, RRM1 and TUBB3 was isolated by a fluorescence-based real-time detection method.

Results: All the patients were followed up until December 2012. One hundred seventy five patients showed good response and 130 patients showed poor response to chemotherapy. 126 patients died and 166 patients showed progressive disease during the follow-up period. The median levels of ERCC1, RRM1 and TUBB3 mRNA were 0.53±0.13, 0.31±0.15 and 0.18±0.16, respectively. We found that patients with low ERCC1 expression showed a significantly higher rate of good tumor response, and the adjusted OR (95% CI) was 2.16(1.32-3.45). By Cox regression analysis. We also found that low ERCC1 expression level were correlated with longer overall survival of NSCLC patients, with the adjusted HR (95% CI) was 2.15 (1.26–3.35).

Conclusion: This study showed that ERCC1 mRNA expression can not affect the response to chemotherapy and clinical outcome of advanced non-small cell lung cancer (NSCLC) patients.

Importance of excision repair cross-complementation group 1 and ribonucleotide reductase M1 as prognostic biomarkers in malignant pleural mesothelioma treated with platinum-based induction chemotherapy followed by surgery

OBJECTIVES

Survival and response to platinum-based induction chemotherapy are heterogeneous among patients with malignant pleural mesothelioma. The aim of the present study was to assess the prognostic role of DNA repair markers, such as excision repair cross-complementation group 1 and ribonucleotide reductase M1, in multimodally treated patients with malignant pleural mesothelioma.

METHODS

Tumor tissue of a malignant pleural mesothelioma cohort (n = 107) treated with platinum/gemcitabine (n = 46) or platinum/pemetrexed (n = 61) induction chemotherapy followed by extrapleural pneumonectomy was assembled on a tissue microarray. Immunohistochemical expression of excision repair cross-complementation group 1 (nuclear) and ribonucleotide reductase M1 (nuclear and cytoplasmic) was assessed for its prognostic impact (association with overall survival or freedom from recurrence).

RESULTS

Patients with high nuclear ribonucleotide reductase M1 expression before chemotherapy showed significantly longer freedom from recurrence (P = .03). When specifically analyzed in the subgroup of patients receiving platinum/gemcitabine followed by extrapleural pneumonectomy, high nuclear ribonucleotide reductase M1 was associated with prolonged freedom from recurrence (P = .03) and overall survival (P = .02). Low excision repair cross-complementation group 1 expression in prechemotherapy tumor tissues was associated with significantly longer freedom from recurrence (P = .04). Nuclear ribonucleotide reductase M1 and excision repair cross-complementation group 1 were independent prognosticators of freedom from recurrence in addition to pT stage in multivariate analysis.

CONCLUSIONS

In the present study, nuclear ribonucleotide reductase M1 and excision repair cross-complementation group 1 expression were identified as independent prognosticators for freedom from recurrence of malignant pleural mesothelioma in patients undergoing induction chemotherapy followed by extrapleural pneumonectomy.

ERCC1 and BRCA1 mRNA expression predicts the clinical outcome of non-small cell lung cancer receiving platinum-based chemotherapy

Objective: We conducted a perspective study to investigate the association between mRNA expression quantities of ERCC1, BRCA1, RRM1 and RRM2 and response to chemotherapy and clinical outcome of advance Non-Small Cell Lung Cancer.(NSCLC).

Methods: Two hundred eight patients who were diagnosed as advanced stage NSCLC were included in our study. A fluorescence-based and real-time detection method was used to determine the relative cDNA quantification for ERCC1, BRCA1, RRM1 and RRM2, and β-actin was used as the reference gene.

Results: The median expression levels of ERCC1, BRCA1, RRM1 and RRM2 mRNA were 0.67±0.17, 0.095±0.012, 0.24±0.17 and 2.45±0.32, respectively. Our study found that the low ERCC1 (OR=1.82, 95% CI=1.01-3.20) and Low BRCA1 (OR=2.53, 95%CI=1.38-4.64) mRNA expression was more likely to response to chemotherapy when compared with high expression, respectively. Multivariate Cox regression analysis indicated that patients with low mRNA expression of ERCC1 and BRCA1 attained 0.43 (OR=0.43, 95%CI=0.27-0.89) and 0.37 (OR=0.37, 95%CI=0.22-0.66) fold risk of death from NSCLC. However, we found RMM1 and RRM2 mRNA expression could not influence the response to chemotherapy and clinical outcome of NSCLC.

Conclusion: ERCC1 and BRCA1 mRNA expression could be important predictive markers for individualized platinum-based chemotherapy for NSCLC patients.

RRM1 maintains centrosomal integrity via CHK1 and CDK1 signaling during replication stress

DNA lesion-induced centrosomal abnormalities during the replication phase are relatively unknown. Here, we report that RNAi-mediated depletion of RRM1 induces cell-cycle arrest at the replication phase, along with severe DNA damage and centrosomal amplification. Interestingly, CHK1 depletion synergistically increased RRM1-depletion-induced centrosomal amplification. In response to hydroxyurea, CHK1 was delocalized from the centrosome by RRM1 depletion. Moreover, CDK1, which functions in centrosome separation and is inhibited by CHK1, was found to be essential for RRMI1-depletion-induced centrosomal amplification. Thus, we herein demonstrate that RRM1 preserves chromosomal stability via the CHK1- and CDK1-dependent stabilization of the centrosomal integrity at the replication stage.

Expression levels of ERCC1 and RRM1 mRNA and clinical outcome of advanced non-small cell lung cancer

Objective: We conducted a study to understand the genetic effect of ERCC1 and RRM1 on the chemotherapy response and clinical outcome of Non-Small Cell Lung Cancer (NSCLC).

Methods: The relative cDNA quantification for ERCC1 and RRM1 was conducted using a fluorescence-based real-time detection method among 294 NSCLC patients.

Results: Compared with the internal reference gene β-action, the median levels of ERCC1 and RRM1 expression were 2.43×10^-2 and 0.11×10^-2, respectively. Our study showed response to platinum-containing regimen chemotherapy was high in those with high ERCC1 expression, and the OR (95% CI) were 1.73(1.06-2.81). An apparently high response to chemotherapy was decreased when patients were carrying both high expression of ERCC1 and RRM1, with OR (95% CI) of 2.57(1.21-4.90). Patients with high expression of ERCC1 were associated with a longer OS by multivariate Cox proportional hazards model. Moreover, those carrying both high levels of ERCC1 and RRM1 were seem to have a longer OS when compared with those with low expression (HR=0.31, 95% CI=0.13-0.62 for OS).

Conclusion: This observation could be used in personalized chemotherapy, increase the response rate and prolonged survival time, and could encourage to explore the predictive value of other genes.

Differences in RRM1 protein expression between diagnostic biopsies and resection specimens, and changes during carboplatin and paclitaxel treatment, in non-small-cell lung cancer

AIMS

It is of interest whether expression of potentially predictive biomarkers changes during chemotherapy, for accurate evaluation after first-line chemotherapy. This study aimed to evaluate changes in RRM1 expression during chemotherapy.

MATERIALS AND METHODS

RRM1 immunohistochemistry was performed on tumour samples from a total of 118 NSCLC patients with stage T1-4N0-2M0 disease. Samples were included from 65 patients treated with paclitaxel and carboplatin before surgery [neoadjuvant chemotherapy (NAC) group], and 53 patients who had undergone surgery but not chemotherapy [operation (OP) group].

RESULTS

Discordant RRM1 expression (low versus high) was observed in 32% and 43% of paired diagnostic and subsequent resection specimens in the OP group and NAC group, respectively (P = 0.913). Ten (33%) and 12 (23%) tumours in the NAC group and the OP group, respectively, had increased RRM1 expression in the resection specimens (P = 0.289), and 12 (40%) and 19 (36%) tumours had decreased expression (P = 0.707). Eleven (50%) lymph node metastases had higher RRM1 expression following chemotherapy, and two (7%) had decreased expression.

CONCLUSIONS

The substantial discordance between paired samples emphasizes the need for sufficient tumour tissue in biopsies when RRM1 expression is evaluated. No change in RRM1 expression was observed in primary tumours, but expression seemed to be higher in N2 lymph node metastases following chemotherapy. Tumour heterogeneity and potential post-chemotherapy changes should be considered when RRM1 expression is evaluated.

The prognostic value of ERCC1 and RRM1 gene expression in completely resected non-small cell lung cancer: tumor recurrence and overall survival

Background

The roles of excision repair cross-complementing group 1 gene (ERCC1) expression and ribonucleotide reductase subunit M1 gene (RRM1) expression in completely resected non-small cell lung cancer (NSCLC) are still debatable. Previous studies have shown that both genes affected the overall survival and outcomes of patients who received platinum-based chemotherapy; however, some studies did not show this correlation. The aim of this study was to evaluate the prognostic values of ERCC1 and RRM1 gene expression in predicting tumor recurrence and overall survival in patients with completely resected NSCLC who received adjuvant chemotherapy and in those who did not.

Patients and methods

A retrospective cohort study was conducted in 247 patients with completely resected NSCLC. All patients had been treated with anatomic resection (lobectomy or pneumonectomy) with systematic mediastinal lymphadenectomy between January 2002 and December 2011 at Chiang Mai University Hospital, Chiang Mai, Thailand. They were divided into two groups: recurrence and no recurrence. Protein expression of ERCC1 and RRM1 was determined by immunohistochemistry. Correlations between clinicopathologic variables, including ERCC1 and RRM1 expression and tumor recurrence, were analyzed. Univariate and multivariate Cox proportional hazards regression analysis stratified by nodal involvement, tumor staging, intratumoral blood vessel invasion, intratumoral lymphatic invasion, and tumor necrosis was used to identify the prognostic roles of ERCC1 and RRM1.

Results

ERCC1 and RRM1 expression did not demonstrate prognostic value for tumor recurrence and overall survival in patients with completely resected NSCLC. In patients who did not receive adjuvant chemotherapy treatment, those with high ERCC1 and high RRM1 expression seemed to have greater potential for tumor recurrence and shorter overall survival than did those who had low ERCC1 and low RRM1 (hazard ratio [HR] =1.7, 95% confidence interval [CI] =0.6–4.3, P=0.292 and HR =1.6, 95% CI =0.5–4.5, P=0.411, respectively). In contrast, in patients who received adjuvant chemotherapy treatment, those with high ERCC1 and high RRM1 expression seemed to have benefited from adjuvant chemotherapy and showed good overall survival compared with those who had low ERCC1 and low RRM1 (HR =0.8, 95% CI = 0.4–1.8, P=0.612 and HR = 0.4, 95% CI = 0.1–2.4, P=0.325, respectively). Subgroup analysis in patients whose first-line metastatic chemotherapy failed demonstrated that ERCC1 expression and RRM1 expression were not prognostic factors for tumor recurrence and overall survival; however, patients who had high ERCC1 and high RRM1 expression seemed to have benefited from first-line chemotherapy treatment (HR =0.7, 95% CI =0.3–1.8, P=0.458).

Conclusion

ERCC1 expression and RRM1 expression were not prognostic of tumor recurrence and overall survival in patients with completely resected NSCLC, either with or without adjuvant chemotherapy. Prospective studies that include a larger number of patients are needed for definite conclusions.

Individualized Chemotherapy in Advanced NSCLC Patients Based on mRNA Levels of BRCA1 and RRM1

OBJECTIVE

Experimental evidence suggests that the overexpression of breast cancer-specific tumor suppressor protein 1 (BRCA1) gene enhances sensitivity to docetaxel and resistance to cisplatin and ribonucleotide reductase M1 (RRM1) gene overexpression enhances resistance to gemcitabine. To further examine the effect of BRCA1 and RRM1 mRNA levels on outcome in advanced non-small cell lung cancer (NSCLC), we performed this non-randomized phase II clinical trial which tested the hypothesis that customized therapy would confer improved outcome over non-customized therapy.

METHODS

RNA was isolated from fresh tumor tissue. Patients received chemotherapy regimen based on their BRCA1 and RRM1 mRNA levels: both low-cisplatin plus gemcitabine (GP); both high-vinorelbine plus cisplatin (NP); BRCA1 low and RRM1 high-cisplatin plus docetaxel (TP); BRCA1 high and RRM1 low-vinorelbine plus gemcitabine (GN).

RESULTS

From Dec 2005 to Nov 2008, 94 metastatic and locally advanced NSCLC patients from our institute were enrolled in this study. The median age was 58 years old. Among them, 21 patients received GP, 30 patients received TP and 43 patients received NP chemotherapy. GP group had a higher response rate, and longer median time to progression (TTP) and median overall survival (OS) time than the other 2 groups. The response rates in the GP, TP and NP groups were 42.9%, 36.7% and 27.9%, respectively (P=0.568). The median TTP was 5.6, 5.0, 4.8 months (P=0.975), respectively, and the median OS time was 12.5, 11.0, 9.7 months (P=0.808), respectively.

CONCLUSION

Chemotherapy customized according to BRCA1 and RRM1 expression levels is associated with higher response rate and longer TTP and OS time in the GP group. This suggests that BRCA1 and RRM1 mRNA levels could be used as biomarkers in individual therapy in NSCLC.

The association between polymorphisms in the DNA nucleotide excision repair genes and RRM1 gene and lung cancer risk

Background  Although numerous studies have investigated the association between DNA repair gene variants and lung cancer risk, the results remain inconclusive and incomplete. Methods  We examined variants in seven nucleotide excision repair (NER) and RRM1 genes in association with primary lung cancer risk among 385 patients with newly diagnosed primary non-small cell lung cancer and 208 cancer-free controls collected from 2007 to 2009 in east China. The relationship between single nucleotide polymorphisms and risk of lung cancer was assessed by logistic regression and stratification analysis. Results  The rs17655GG (ERCC5) and rs5744751CT (POLE) were associated with increased risk of lung cancer (adjusted odds ratio [OR], 2.32, 95% confidence interval [CI], 1.41-3.83; adjusted OR, 2.84, 95% CI, 1.70-4.74]. In stratification analysis, we found the increased effect of rs17655GG on the risk of lung cancer was observed among female, older subjects, or non-smokers. The heterozygote computed tomography (CT) of rs5744751 had a stronger unprotective effect on lung cancer among male, older subjects, or heavy smokers. Conclusion  These results suggest that rs17655GG and rs5744751CT may be associated with lung cancer susceptibility in the Chinese population. However, these findings still need to be verified in larger confirmatory studies.

Response to gemcitabine-platinum chemotherapy by single nucleotide polymorphisms of RRM1 and ERCC1 genes in patients with non-small-cell lung cancer

BACKGROUND

  RRM1, the regulatory subunit of ribonucleotide reductase, is involved in carcinogenesis and the response to gemcitabine. Two single nucleotide polymorphisms (SNP) in the RRM1 gene (RR37 and RR524) impact promoter activity and are associated with prognosis. The excision repair cross-complementation group 1 protein (ERCC1) is associated with platinum resistance. A SNP of the ERCC1 gene (T19007C) has been reported as a prognostic marker in platinum-treated non-small-cell lung cancer (NSCLC).

MATERIALS AND METHODS

  Patients with stage IIIB or IV NSCLC were treated with gemcitabine and platinum (GP) as first-line chemotherapy. Adenocarcinoma was the most frequent histological type, followed by squamous cell carcinoma and then other types. SNP were analyzed with real time-polymerase chain reaction using genomic DNA extracted from peripheral blood.

RESULTS

  Based on responses to GP patients were classified as responders or non-responders. The response rate was significantly higher in patients with the RR AC-CT genotype (35/64, 54.7%) compared to those with the RR CC-TT genotype (56/147, 38.1%, P= 0.025). No significant difference in response rate was observed according to ERCC1 genotype. In 128 patients with non-squamous cell lung cancer, RR AC-CT + ERCC1 CC (63.2%) and RR AC-CT + ERCC1 CT/TT (61.9%) showed higher response rates compared to RR CC-TT + ERCC1 CC (36.5%), and RR CC-TT + ERCC1 CT/TT (22.2%; P= 0.004). Progression-free and overall survival times were not different between genotypes.

CONCLUSIONS

  We observed significantly different responses to the GP regimen according to SNP of the RRM1 and ERCC1 genes.

The expression of ERCC1, RRM1, and BRCA1 in breast cancer according to the immunohistochemical phenotypes

We studied the expression of BRCA1, ERCC1, and RRM1 which play an important role in DNA repair systems in breast cancer. Immunohistochemical staining for EGFR, BRCA1, ERCC1, and RRM1 were performed by using a tissue microarray made from 230 breast cancer patients. Patients were classified into luminal A, luminal B, HER-2, and triple negative breast cancer (TNBC) types according to ER, PR, and HER-2 expression. The expression of ERCC1, RRM1, and BRCA1 were correlated (P < 0.05). The expression level of ERCC1 was the lowest in TNBC type (P = 0.031), ERCC1 negativity was more prominent in TNBC and luminal B groups than luminal A and HER-2 groups (P = 0.013). Cases with EGFR overexpression showed high expression of RRM1 and BRCA1 (P = 0.046, and 0.004, respectively). In conclusion, the expression of ERCC1 is particularly lower in TNBCs than other types of breast cancers.

The potential role of pharmacogenomic and genomic in the adjuvant treatment of early stage non small cell lung cancer

Although notable progress has been made in the treatment of non-small-cell lung cancer (NSCLC) in recent years, this disease is still associated with a poor prognosis. Despite early-stage NSCLC is considered a potentially curable disease following complete resection, the majority of patients relapse and eventually die after surgery. Adjuvant chemotherapy prolongs survival, altough the absolute improvement in 5-year overall survival is only approximately 5%.Trying to understand the role of genes which could affect drug activity and response to treatment is a major challenge for establishing an individualised chemotherapy according to the specific genetic profile of each patient. Among genes involved in the DNA repair system, the excision repair cross-complementing 1 (ERCC1) is a useful markers of clinical resistance to platinum-based chemotherapy. In the International Lung Cancer Trial (IALT) adjuvant chemotherapy significantly prolonged survival among patients with ERCC1 negative tumors but not among ERCC1-positive patients. BRCA1 and ribonucleotide reductase M1 (RRM1), two other key enzymes in DNA synthesis and repair, appear to be modulators of drug sensitivity and may provide additional information for customizing adjuvant chemotherapy.Several clinical trials suggest that overexpression of class III beta-tubulin is an adverse prognostic factor in cancer since it could be responsible for resistance to anti-tubulin agents. A retrospective analysis of NCIC JBR.10 trial showed that high tubulin III expression is associated with a higher risk of relapse following surgery alone but also with a higher probability of benefit from adjuvant cisplatin plus vinorelbine chemotherapy.Finally, the use of gene expression patterns such as the lung metagene model could provide a potential mechanism to refine the estimation of a patient's risk of disease recurrence and could affect treatment decision in the management of early stage of NSCLC.In this review we will discuss the potential role of pharmacogenomic approaches to guide the medical treatment of early stage NSCLC.