Research IndicatorsGraph generated 14 March 2017 using data from PubMed using criteria.
Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic. Tag cloud generated 14 March, 2017 using data from PubMed, MeSH and CancerIndex
Specific Cancers (6)
Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.
Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).
OMIM, Johns Hopkin University
Referenced article focusing on the relationship between phenotype and genotype.
International Cancer Genome Consortium.
Summary of gene and mutations by cancer type from ICGC
Cancer Genome Anatomy Project, NCI
COSMIC, Sanger Institute
Somatic mutation information and related details
GEO Profiles, NCBI
Search the gene expression profiles from curated DataSets in the Gene Expression Omnibus (GEO) repository.
Latest Publications: ABCC2 (cancer-related)
We determined the gene expression profiles for 48 ATP binding cassette (ABC) transporters in matched colon cancer and normal colon tissues in order to provide insight into the mechanisms underlying expression of transporters related to colon carcinogenesis. The expression of ABCB1, ABCC1, ABCC2, ABCC3, and ABCG2 was altered in association with colon carcinogenesis. Among these transporters, the expression of ABCC3 was repressed by Wnt signaling pathway in colon cancer cell lines. Knockdown of the pathway components transcription factor 7-like 2 (TCF7L2) or β-catenin thus increased ABCC3 expression, whereas activation of Wnt signaling with inhibitors of glycogen synthase kinase-3β (GSK-3β) reduced it. ChIP and luciferase reporter assays also showed that TCF7L2 binds to the ABCC3 locus and regulates its expression. Finally, overexpression of ABCC3 in colon cancer cells conferred resistance to anticancer drug-induced cytotoxicity. Our data thus suggest that Wnt signaling represses ABCC3 expression during colon carcinogenesis, and that subsequent upregulation of ABCC3 expression during drug treatment might contribute to acquired drug resistance.
Bigagli E, De Filippo C, Castagnini C, et al.DNA copy number alterations, gene expression changes and disease-free survival in patients with colorectal cancer: a 10 year follow-up.
Cell Oncol (Dordr). 2016; 39(6):545-558 [PubMed
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BACKGROUND: DNA copy number alterations (CNAs) and gene expression changes have amply been encountered in colorectal cancers (CRCs), but the extent at which CNAs affect gene expression, as well as their relevance for tumor development, are still poorly defined. Here we aimed at assessing the clinical relevance of these parameters in a 10 year follow-up study.
METHODS: Tumors and normal adjacent colon mucosa, obtained at primary surgery from 21 CRC patients, were subjected to (i) high-resolution array CGH (a-CGH) for the detection of CNAs and (ii) microarray-based transcriptome profiling for the detection of gene expression (GE) changes. Correlations between these genomic and transcriptomic changes and their associations with clinical and histopathological parameters were assessed with the aim to identify molecular signatures associated with disease-free survival of the CRC patients during a 10 year follow-up.
RESULTS: DNA copy number gains were frequently detected in chromosomes 7, 8q, 13, 19, 20q and X, whereas DNA copy number losses were frequently detected in chromosomes 1p, 4, 8p, 15, 17p, 18, 19 and 22q. None of these alterations were observed in all samples. In addition, we found that 2,498 genes were up- and that 1,094 genes were down-regulated in the tumor samples compared to their corresponding normal mucosa (p < 0.01). The expression of 65 genes was found to be significantly associated with prognosis (p < 0.01). Specifically, we found that up-regulation of the IL17RA, IGF2BP2 and ABCC2 genes, and of genes acting in the mTOR and cytokine receptor pathways, were strongly associated with a poor survival. Subsequent integrated analyses revealed that increased expression levels of the MMP9, BMP7, UBE2C, I-CAM, NOTCH3, NOTCH1, PTGES2, HMGB1 and ERBB3 genes were associated with copy number gains, whereas decreased expression levels of the MUC1, E2F2, HRAS and SIRT3 genes were associated with copy number losses. Pathways related to cell cycle progression, eicosanoid metabolism, and TGF-β and apoptosis signaling, were found to be most significantly affected.
CONCLUSIONS: Our results suggest that CNAs in CRC tumor tissues are associated with concomitant changes in the expression of cancer-related genes. In other genes epigenetic mechanism may be at work. Up-regulation of the IL17RA, IGF2BP2 and ABCC2 genes, and of genes acting in the mTOR and cytokine receptor pathways, appear to be associated with a poor survival. These alterations may, in addition to Dukes' staging, be employed as new prognostic biomarkers for the prediction of clinical outcome in CRC patients.
BACKGROUND: Crocin, one of the main constituents of saffron extract, has numerous biological effects such as anti-cancer effects. Multidrug resistance-associated proteins 1 and 2 (MRP1 and MRP2) are important elements in the failure of cancer chemotherapy. In this study we aimed to evaluate the effects of crocin on MRP1 and MRP2 expression and function in human ovarian cancer cell line A2780 and its cisplatin-resistant derivative A2780/RCIS cells.
METHODS: The cytotoxicity of crocin was assessed by the MTT assay. The effects of crocin on the MRP1 and MRP2 mRNA expression and function were assessed by real-time RT-PCR and MTT assays, respectively.
RESULTS: Our study indicated that crocin reduced cell proliferation in a dose-dependent manner in which the reduction in proliferation rate was more noticeable in the A2780 cell line compared to A2780/RCIS. Crocin reduced MRP1 and MRP2 gene expression at the mRNA level in A2780/RCIS cells. It increased doxorubicin cytotoxicity on the resistant A2780/RCIS cells in comparison with the drug-sensitive A2780 cells.
CONCLUSION: Totally, these results indicated that crocin could suppress drug resistance via down regulation of MRP transporters in the human ovarian cancer resistant cell line.
Šemeláková M, Jendželovský R, Fedoročko PDrug membrane transporters and CYP3A4 are affected by hypericin, hyperforin or aristoforin in colon adenocarcinoma cells.
Biomed Pharmacother. 2016; 81:38-47 [PubMed
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Our previous results have shown that the combination of hypericin-mediated photodynamic therapy (HY-PDT) at sub-optimal dose with hyperforin (HP) (compounds of Hypericum sp.), or its stable derivative aristoforin (AR) stimulates generation of reactive oxygen species (ROS) leading to antitumour activity. This enhanced oxidative stress evoked the need for an explanation for HY accumulation in colon cancer cells pretreated with HP or AR. Generally, the therapeutic efficacy of chemotherapeutics is limited by drug resistance related to the overexpression of drug efflux transporters in tumour cells. Therefore, the impact of non-activated hypericin (HY), HY-PDT, HP and AR on cell membrane transporter systems (Multidrug resistance-associated protein 1-MRP1/ABCC1, Multidrug resistance-associated protein 2-MRP2/ABCC2, Breast cancer resistance protein - BCRP/ABCG2, P-glycoprotein-P-gp/ABCC1) and cytochrome P450 3A4 (CYP3A4) was evaluated. The different effects of the three compounds on their expression, protein level and activity was determined under specific PDT light (T0+, T6+) or dark conditions (T0- T6-). We found that HP or AR treatment affected the protein levels of MRP2 and P-gp, whereas HP decreased MRP2 and P-gp expression mostly in the T0+ and T6+ conditions, while AR decreased MRP2 in T0- and T6+. Moreover, HY-PDT treatment induced the expression of MRP1. Our data demonstrate that HP or AR treatment in light or dark PDT conditions had an inhibitory effect on the activity of individual membrane transport proteins and significantly decreased CYP3A4 activity in HT-29 cells. We found that HP or AR significantly affected intracellular accumulation of HY in HT-29 colon adenocarcinoma cells. These results suggest that HY, HP and AR might affect the efficiency of anti-cancer drugs, through interaction with membrane transporters and CYP3A4.
Liu XY, Liu SP, Jiang J, et al.Inhibition of the JNK signaling pathway increases sensitivity of hepatocellular carcinoma cells to cisplatin by down-regulating expression of P-glycoprotein.
Eur Rev Med Pharmacol Sci. 2016; 20(6):1098-108 [PubMed
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OBJECTIVE: The resistance of hepatocellular carcinoma (HCC) to chemotherapy may be mediated by the c-Jun N-terminal kinase (JNK) pathway. We wished to verify the involvement of this pathway in resistance of HCC cells to cisplatin.
MATERIALS AND METHODS: We used HepG2 cell line and cisplatin-resistant clone (HepG2/DDP). Expressions of drug resistance and apoptosis-related genes were analyzed by qPCR. Protein expressions were assessed by Western blot. The JNK pathway was assessed as total JNK1/2 and JNK1/2 phosphorylation. Cell growth kinetics was quantified by the CCK-8 assay, and cell apoptosis (Annexin V / propidium iodide) by flow cytometry.
RESULTS: HepG2/DDP cells were more resistant and less apoptotic on cisplatin. Expression of drug-resistance genes MDR1, MRP1 and MPR2 was significantly up-regulated in HepG2/DDP cells (p < 0.05), with up-regulation of MDR1 being the highest. This was confirmed by Western blot analysis of P-glycoprotein (P-gp), MRP1 and MRP2 proteins, the proteins encoded by the above genes. Expression of anti-apoptotic genes Bcl-2 and Bcl-XL was significantly up-regulated, and expression of pro-apoptotic genes Bak and Bad was significantly reduced, in HepG2/DDP cells (p < 0.05). Cisplatin treatment of HepG2 led to increased phosphorylation of JNK1/2; the trend reversed by the inhibitor SP600125. Furthermore, cisplatin increased expression of P-gp, which was also attenuated by SP600125. Cell growth was inhibited more substantially, and cell apoptosis promoted, when HepG2 cells were exposed to both cisplatin and SP600125.
CONCLUSIONS: Inhibition of the JNK signaling pathway enhances the sensitivity of HCC cells to cisplatin by down-regulating the expression of P-gp.
Samatiwat P, Prawan A, Senggunprai L, et al.Nrf2 inhibition sensitizes cholangiocarcinoma cells to cytotoxic and antiproliferative activities of chemotherapeutic agents.
Tumour Biol. 2016; 37(8):11495-507 [PubMed
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Nuclear factor erythroid 2-related factor 2 (Nrf2), a key transcription factor regulating antioxidant, cytoprotective, and metabolic enzymes, plays important roles in drug resistance and proliferation in cancer cells. The present study was aimed to examine the expression of Nrf2 in connection with chemotherapeutic drug sensitivity on cholangiocarcinoma (CCA) cells. The basal levels of Nrf2 protein in cytosol and nuclear fractions of CCA cells were determined using Western blot analysis. Nrf2 mRNA expression of KKU-M156 and KKU-100 cells, representatives of low and high-Nrf2-expressing CCA cells, were silenced using siRNA. After knockdown of Nrf2, the sensitivity of those cells to the cytotoxicity of cisplatin (Cis) was enhanced in association with the increased release of AIF and downregulation of Bcl-xl in both cells. Also, knockdown of Nrf2 suppressed the replicative capability of those cells in colony-forming assay and enhanced their sensitivity to antiproliferative activity of Cis and 5-fluorouracil. The chemosensitizing effect was associated with the suppressed expression of Nrf2-regulated and Cis-induced antioxidant and metabolic genes including NQO1, HO-1, GCLC, TXN, MRP2, TKT, and G6PD. In cell cycle analysis, Nrf2 knockdown cells were arrested at G0/G1 phase and combination with Cis increased the accumulation of cells at S phase. The suppression of KKU-M156 cell proliferation was associated with the downregulation of cyclin D1 and increased level of p21. Inhibition of Nrf2 could be a novel strategy in enhancing antitumor activity of chemotherapeutic agent in control of resistant cancer.
Runt-related transcription factor 3 (RUNX3) is known to function as a tumor suppressor in gastric cancer and other types of cancers, including hepatocellular carcinoma (HCC). However, its role has not been fully elucidated. In the present study, we aimed to evaluate the role of RUNX3 in HCC. We used the human HCC cell lines Hep3B, Huh7 and HLF; RUNX3 cDNA was introduced into Hep3B and Huh7 cells, which were negative for endogenous RUNX3 expression, and RUNX3 siRNA was transfected into HLF cells, which were positive for endogenous RUNX3. We analyzed the expression of RUNX3 and multidrug resistance-associated protein (MRP) by immunoblotting. MTT assays were used to determine the effects of RUNX3 expression on 5-fluorouracil (5-FU) and cisplatin (CDDP) sensitivity. Finally, 23 HCC specimens resected from patients with HCC at Okayama University Hospital were analyzed, and correlations among immunohistochemical expression of RUNX3 protein and MRP protein were evaluated in these specimens. Exogenous RUNX3 expression reduced the expression of MRP1, MRP2, MRP3 and MRP5 in the RUNX3-negative cells, whereas knockdown of RUNX3 in the HLF cells stimulated the expression of these MRPs. An inverse correlation between RUNX3 and MRP expression was observed in the HCC tissues. Importantly, loss of RUNX3 expression contributed to 5-FU and CDDP resistance by inducing MRP expression. These data have important implications in the study of chemotherapy resistance in HCC.
Campos-Arroyo D, Maldonado V, Bahena I, et al.Probenecid Sensitizes Neuroblastoma Cancer Stem Cells to Cisplatin.
Cancer Invest. 2016; 34(3):155-66 [PubMed
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We used both in vitro cultures of neuroblastoma cell lines and nude-mice xenotransplants to explore the effects of co-administration of cisplatin and probenecid. Probenecid sensitized neuroblastoma cells, including tumor cells with stem features, to the effects of cisplatin, both in vitro and in vivo. This effect was mediated by an increase in the apoptotic cell death and a concomitant decrease in cell proliferation. This effect is accompanied by modulation of the mRNA and protein of the drug efflux transporters MDR1, MRP2, and BCRP. The co-administration of probenecid with cisplatin should be explored as a possible therapeutic strategy.
Ye P, Xing H, Lou F, et al.Histone deacetylase 2 regulates doxorubicin (Dox) sensitivity of colorectal cancer cells by targeting ABCB1 transcription.
Cancer Chemother Pharmacol. 2016; 77(3):613-21 [PubMed
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PURPOSE: Histone deacetylases (HDACs) have been shown to regulate cell cycle, differentiation, and apoptosis of colorectal cancer (CRC) cells, while their roles in drug sensitivity remain unclear. The objectives of the present study were to investigate the effects of HDAC2 on drug resistance of CRC cells.
METHODS: We measured the expression of class I HDACs (HDAC1, 2, 3, 8) in CRC and human normal colonic epithelial cells. Additionally, we inhibited HDAC2 via siRNA or overexpressed it via pcDNA/HDAC2 transfection to evaluate its roles in doxorubicin (Dox) sensitivity.
RESULTS: Our present study showed HDAC2 was significantly increased in CRC cell lines as compared to human normal colonic epithelial cells. Silencing of HDAC2 can obviously enhance the sensitivity of HCT-116 and SW480 cells to dDox. Further, knockdown of HDAC2 can significantly (p < 0.05) downregulate the expression of ABCB1, while not ABCG2, ABCC1, ABCA1, or ABCC2. Inhibition of HDAC2 decreased ABCB1 promoter activities and the phosphorylation of c-fos and c-Jun, which can directly interact with the ABCB1 promoter and then promote its transcription. Overexpression of HDAC2 by pcDNA/HDAC2 transfection significantly increased the sensitivity of CRC cells to Dox and upregulated the levels of P-gp, p-c-fos, and p-c-Jun.
CONCLUSIONS: Our data revealed that HDAC2 can regulate Dox sensitivity of CRC cells by targeting ABCB1 transcription. It suggested that HDAC2 might be an important target for CRC therapy. Further, the combination of HDAC2-specific inhibitor and anticancer drugs including Dox might be an efficiency approach to elevate the treatment outcome of CRC.
Cuffe S, Azad AK, Qiu X, et al.ABCC2 polymorphisms and survival in the Princess Margaret cohort study and the NCIC clinical trials group BR.24 trial of platinum-treated advanced stage non-small cell lung cancer patients.
Cancer Epidemiol. 2016; 41:50-6 [PubMed
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BACKGROUND: The drug transporter ABCC2 is upregulated in non-small cell lung cancer (NSCLC) and implicated in platinum resistance. We evaluated the association between germline polymorphisms in the ABCC2 gene and survival outcomes of platinum-treated advanced NSCLC patients.
MATERIAL AND METHODS: Ten candidate and tagging germline polymorphisms in the ABCC2 gene were genotyped in a discovery cohort of 170 platinum-treated stage IV NSCLC patients from the Princess Margaret Cancer Centre. Associations with overall survival were assessed using multivariate Cox proportional hazard models adjusted for prognostic variables. To validate our results, we analyzed the association of the two top polymorphisms in the ABCC2 gene on survival outcomes of 219 stage IIIB-IV NSCLC patients enrolled on the NCIC Clinical Trials Group BR.24 clinical trial.
RESULTS: Only one polymorphism was validated across both cohorts for an association with overall survival: the A allele of the ABCC2 polymorphism, rs8187710 (4544G>A), was associated with adverse overall survival (adjusted hazard ratio [aHR] 2.22; 95% CI: 1.2-4.0; p=0.009) among our stage IV NSCLC patients. A significant association with overall survival (aHR 1.73; 95% CI: 1.0-2.9; p=0.036) was observed for the same ABCC2 polymorphism in the BR.24 validation cohort. No other ABCC2 polymorphisms were associated with outcome.
CONCLUSION: The ABCC2 polymorphism, rs8187710 (4544G>A), is associated with overall survival in platinum-treated advanced NSCLC patients. Additional studies are needed to evaluate the predictive versus prognostic nature of this relationship, and to explore the functional effect of this polymorphism on the pharmacokinetics of platinum drugs.
Litviakov NV, Cherdyntseva NV, Tsyganov MM, et al.Deletions of multidrug resistance gene loci in breast cancer leads to the down-regulation of its expression and predict tumor response to neoadjuvant chemotherapy.
Oncotarget. 2016; 7(7):7829-41 [PubMed
] Free Access to Full Article Related Publications
Neoadjuvant chemotherapy (NAC) is intensively used for the treatment of primary breast cancer. In our previous studies, we reported that clinical tumor response to NAC is associated with the change of multidrug resistance (MDR) gene expression in tumors after chemotherapy. In this study we performed a combined analysis of MDR gene locus deletions in tumor DNA, MDR gene expression and clinical response to NAC in 73 BC patients. Copy number variations (CNVs) in biopsy specimens were tested using high-density microarray platform CytoScanTM HD Array (Affymetrix, USA). 75%-100% persons having deletions of MDR gene loci demonstrated the down-regulation of MDR gene expression. Expression of MDR genes was 2-8 times lower in patients with deletion than in patients having no deletion only in post-NAC tumors samples but not in tumor tissue before chemotherapy. All patients with deletions of ABCB1 ABCB 3 ABCC5 gene loci--7q21.1, 6p21.32, 3q27 correspondingly, and most patients having deletions in ABCC1 (16p13.1), ABCC2 (10q24), ABCG1 (21q22.3), ABCG2 (4q22.1), responded favorably to NAC. The analysis of all CNVs, including both amplification and deletion showed that the frequency of 13q14.2 deletion was 85% among patients bearing tumor with the deletion at least in one MDR gene locus versus 9% in patients with no deletions. Differences in the frequency of 13q14.2 deletions between the two groups were statistically significant (p = 2.03 × 10(-11), Fisher test, Bonferroni-adjusted p = 1.73 × 10(-8)). In conclusion, our study for the first time demonstrates that deletion MDR gene loci can be used as predictive marker for tumor response to NAC.
Rumiato E, Boldrin E, Malacrida S, et al.A germline predictive signature of response to platinum chemotherapy in esophageal cancer.
Transl Res. 2016; 171:29-37.e1 [PubMed
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Platinum-based neoadjuvant therapy is the standard treatment for esophageal cancer (EC). At present, no reliable response markers exist, and patient therapeutic outcome is variable and very often unpredictable. The aim of this study was to understand the contribution of host constitutive DNA polymorphisms in discriminating between responder and nonresponder patients. DNA collected from 120 EC patients treated with platinum-based neoadjuvant chemotherapy was analyzed using drug metabolism enzymes and transporters (DMET) array platform that interrogates polymorphisms in 225 genes of drug metabolism and disposition. Four gene variants of DNA repair machinery, 2 in ERCC1 (rs11615; rs3212986), and 2 in XPD (rs1799793; rs13181) were also studied. Association analysis was performed with pTest software and corrected by permutation test. Predictive models of response were created using the receiver-operating characteristics curve approach and adjusted by the bootstrap procedure. Sixteen single nucleotide polymorphisms (SNPs) of the DMET array resulted significantly associated with either good or poor response; no association was found for the 4 variants mapping in DNA repair genes. The predictive power of 5 DMET SNPs mapping in ABCC2, ABCC3, CYP2A6, PPARG, and SLC7A8 genes was greater than that of clinical factors alone (area under the curve [AUC] = 0.74 vs 0.62). Interestingly, their combination with the clinical variables significantly increased the predictivity of the model (AUC = 0.78 vs 0.62, P = 0.0016). In conclusion, we identified a genetic signature of response to platinum-based neoadjuvant chemotherapy in EC patients. Our results also disclose the potential benefit of combining genetic and clinical variables for personalized EC management.
The mechanism of resistance of hepatocellular carcinoma (HCC) to sorafenib is unknown and no useful predictive biomarker for sorafenib treatment has been reported. Accordingly, we established sorafenib-resistant HCC cells and investigated the underlying mechanism of resistance to sorafenib. Sorafenib-resistant cell lines were established from the HCC cell line PLC/PRF5 by cultivation under continuous exposure to increasing concentration of sorafenib. The IC50 values of the 2 resistant clones PLC/PRF5-R1 and PLC-PRF5-R2 were 9.2±0.47 μM (1.8-fold) and 25±5.1 μM (4.6-fold) respectively, which were significantly higher than that of parental PLC/PRF5 cells (5.4±0.17 μM) (p < 0.01 respectively), as determined by MTT assay. Western blot analysis of signal transduction-related proteins showed no significant differences in expression of AKT/pAKT, mTOR/pmTOR, or ERK/pERK between the 2 resistant clones versus parent cells, suggesting no activation of an alternative signal transduction pathway. Likewise, when expression of membrane transporter proteins was determined, there were no significant differences in expression levels of BSEP, MDR1, MRP2, BCRP, MRP4 and OCT1 between resistant clones and parent cells. However, the expression levels of MRP3 in the 2 resistant clones were significantly higher than that of parent cells. When MRP3 gene was knocked down by siRNA in PLC-PRF5-R2 cells, the sensitivity of the cells to sorafenib was restored. In the analysis of gene mutation, there was no mutation in the activation segment of Raf1 kinase in the resistant clones. Our data clearly demonstrate that the efflux transporter MRP3 plays an important role in resistance to sorafenib in HCC cells.
Paclitaxel-induced peripheral neuropathy (PIPN) cannot be predicted from clinical parameters and might have a pharmacogenomic basis. Previous studies identified single nucleotide variants (SNV) associated with PIPN. However, only a subset of findings has been confirmed to date in more than one study, suggesting a need for further re-testing and validation in additional clinical cohorts. Candidate PIPN-associated SNVs were identified from the literature. SNVs were retested in 119 patients selected by extreme phenotyping from 269 in NCCTG N08C1 (Alliance) as previously reported. SNV genotyping was performed by a combination of short-read sequencing analysis and Taqman PCR. These 22 candidate PIPN SNVs were genotyped. Two of these, rs7349683 in the EPHA5 and rs3213619 in ABCB1 were found to be significantly associated with PIPN with an Odds ratios OR = 2.07 (P = 0.02) and OR = 0.12 (P = 0.03), respectively. In addition, three SNVs showed a trend toward a risk- or protective effect that was consistent with previous reports. The rs10509681 and rs11572080 in the gene CYP2C8*3 showed risk effect with an OR = 1.49 and rs1056836 in CYP1B1 showed a protective effect with an OR = 0.66. None of the other results supported the previously reported associations, including some SNVs displaying an opposite direction of effect from previous reports, including rs1058930 in CYP2C8, rs17222723 and rs8187710 in ABCC2, rs10771973 in FGD4, rs16916932 in CACNB2 and rs16948748 in PITPNA. Alliance N08C1 validated or supported a minority of previously reported SNV-PIPN associations. Associations previously reported by multiple studies appeared to have a higher likelihood to be validated by Alliance N08C1.
Shinozuka K, Tang H, Jones RB, et al.Impact of Polymorphic Variations of Gemcitabine Metabolism, DNA Damage Repair, and Drug-Resistance Genes on the Effect of High-Dose Chemotherapy for Relapsed or Refractory Lymphoid Malignancies.
Biol Blood Marrow Transplant. 2016; 22(5):843-9 [PubMed
] Related Publications
The goal of this study was to determine whether single nucleotide polymorphisms (SNPs) in genes involved in gemcitabine metabolism, DNA damage repair, multidrug resistance, and alkylator detoxification influence the clinical outcome of patients with refractory/relapsed lymphoid malignancies receiving high-dose gemcitabine/busulfan/melphalan (Gem/Bu/Mel) with autologous stem cell support. We evaluated 21 germline SNPs of the gemcitabine metabolism genes CDA, deoxycytidine kinase, and hCNT3; DNA damage repair genes RECQL, X-ray repair complementing 1, RAD54L, ATM, ATR, MLH1, MSH2, MSH3, TREX1, EXO1, and TP73; and multidrug-resistance genes MRP2 and MRP5; as well as glutathione-S-transferase GSTP1 in 153 patients with relapsed or refractory lymphoma or myeloma receiving Gem/Bu/Mel. We studied the association of genotypes with overall survival (OS), progression-free survival (PFS), and nonhematological grade 3 or 4 toxicity. CDA C111T and TREX1 Ex14-460C>T genotypes had a significant effect on OS (P = .007 and P = .005, respectively), and CDA C111T, ATR C340T, and EXO1 P757L genotypes were significant predictors for severe toxicity (P = .037, P = .024, and P = .025, respectively) in multivariable models that adjusted for clinical variables. The multi-SNP risk score analysis identified the combined genotypes of TREX1 Ex14-460 TT and hCNT3 Ex5 +25A>G AA as significant predictors for OS and the combination of MRP2 Ex10 + 40GG/GA and MLH1 IVS12-169 TT as significant predictor for PFS. Polymorphic variants of certain genes involved in gemcitabine metabolism and DNA damage repair pathways may be potential biomarkers for clinical outcome in patients with refractory/relapsed lymphoid tumors receiving Gem/Bu/Mel.
Karatas OF, Guzel E, Duz MB, et al.The role of ATP-binding cassette transporter genes in the progression of prostate cancer.
Prostate. 2016; 76(5):434-44 [PubMed
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BACKGROUND: Prostate cancer (PCa) is the most commonly diagnosed neoplasm and the second leading cause of cancer-related death among men in developed countries. There is no clear evidence showing the success of current screening tests in reducing mortality of PCa. In this study, we aimed to profile expressions of nine ABC transporters, ABCA5, ABCB1, ABCB6, ABCC1, ABCC2, ABCC3, ABCC5, ABCC10, and ABCF2, in recurrent, non-recurrent PCa and normal prostate tissues.
METHODS: A total of 77 (39 recurrent, 38 non-recurrent) radical prostatectomy and 20 normal prostate samples, obtained from Baylor College of Medicine Prostate Cancer program, were included into the study and divided into two independent groups as test and validation sample sets. Differential expression of selected ABC transporters was assessed using quantitative real-time PCR (qRT-PCR). Pearson's correlation test, receiver operating characteristics (ROC) analysis and Kaplan-Meier test were used for statistical analysis.
RESULTS: QRT-PCR results demonstrated the elevated expression of ABCA5, ABCB1, ABCB6, ABCC1, and ABCC2 as well as reduced expression of ABCC3 in PCa samples compared to normal prostate tissues. In addition, we found deregulation of ABCB1, ABCB6, ABCC3, and ABCC10 in recurrent PCa samples and validated differential expression of ABCB6, ABCC3, and ABCC10 in recurrent PCa compared to non-recurrent PCa. Pearson's correlation, ROC and Kaplan-Meier analysis revealed the power of these three ABC transporters for estimating prognosis of PCa.
CONCLUSIONS: We demonstrated differential expression of ABC transporters both in tumor versus normal and recurrent versus non-recurrent comparisons. Our data suggest ABCB6, ABCC3, and ABCC10 as valuable predictors of PCa progression.
Gao CC, Xu XL, Li F, et al.Silencing pancreatic adenocarcinoma upregulated factor (PAUF) increases the sensitivity of pancreatic cancer cells to gemcitabine.
Tumour Biol. 2016; 37(6):7555-64 [PubMed
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Pancreatic adenocarcinoma upregulated factor (PAUF) is a new oncogene that activates signaling pathways that play a critical role in resistance to gemcitabine. We thus speculated that PAUF also plays a role in resistance to gemcitabine of pancreatic cancer cells. We established BxPC-3 cell lines with stable PAUF knockdown (BxPC-3_shPAUF) and controls (BxPC-3_shCtrl) and evaluated sensitivity to gemcitabine in vitro by MTT and flow cytometry. We established a xenograft model of human pancreatic cancer to examine PAUF function in gemcitabine resistance in vivo. Gene chip microarrays were performed to identify differentially expressed genes in BxPC-3_shPAUF and BxPC-3_shCtrl cells. Silencing PAUF increased the sensitivity of BxPC-3 cells to gemcitabine in vitro and in vivo. PAUF-knockdown BxPC-3 cell lines treated with gemcitabine showed increased proliferation inhibition and apoptosis compared with controls. Gemcitabine exhibited a more pronounced effect on reduction of BxPC-3_shPAUF tumors than BxPC-3_shCtrl tumors. Terminal deoxynucleotidyl transferase dUTP Nick-End Labeling (TUNEL) assays confirmed a significantly higher apoptotic rate of BXPC-3_shPAUF tumors compared with BXPC-3_shCtrl tumors. Gene array showed that PAUF function in gemcitabine sensitivity might involve MRP2, MRP3, MDR1, PIK3R1, and NFkB2 genes. PAUF could be considered as a key molecular target for sensitizing pancreatic cancer cells to gemcitabine.
Chen S, Villeneuve L, Jonker D, et al.ABCC5 and ABCG1 polymorphisms predict irinotecan-induced severe toxicity in metastatic colorectal cancer patients.
Pharmacogenet Genomics. 2015; 25(12):573-83 [PubMed
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OBJECTIVE: Irinotecan is a cytotoxic agent used widely for the treatment of solid tumors, particularly for metastatic colorectal cancers. Treatment with this drug frequently results in severe neutropenia and diarrhea that can markedly impact the course of treatment and patients' quality of life. Pharmacogenomic tailoring of irinotecan-based chemotherapy has been the subject of several investigations, but with limited data on ATP-binding cassette (ABC) and solute carrier (SLC) transporter genes.
MATERIALS AND METHODS: In this study, we aimed to discover toxicity-associated markers in seven transporter genes participating in irinotecan pharmacokinetics involving the ABC transporter genes ABCB1, ABCC1, ABCC2, ABCC5, ABCG1, and ABCG2 and the solute carrier organic anion transporter gene SLCO1B1 and using a haplotype-tagging single-nucleotide polymorphisms (n=210 htSNPs) strategy. The profiles of 167 metastatic colorectal cancer Canadian patients treated with FOLFIRI-based regimens were examined and the findings were replicated in an independent cohort of 250 Italian patients.
RESULTS: In combined cohorts, a two-marker ABCC5 rs3749438 and rs10937158 haplotype (T-C) predicted lower risk of severe diarrhea [odds ratio (OR) of 0.43; P=0.001]. The co-occurrence of ABCG1 rs225440T and ABCC5 rs2292997A predicted the risk of severe neutropenia (OR=5.93; P=0.0002), which was further improved when incorporating the well-known risk marker UGT1A1*28 rs8175347 (OR=7.68; P<0.0001). In contrast, carriers of one protective marker (UGT1 rs11563250G) but none of these risk alleles experienced significantly less severe neutropenia (8.2 vs. 34.0%; P<0.0001).
CONCLUSION: This combination of predictive genetic markers could potentially lead to better risk assessment and may thus improve personalized treatment.
Liu XC, Lian W, Zhang LJ, et al.Interleukin-18 Down-Regulates Multidrug Resistance-Associated Protein 2 Expression through Farnesoid X Receptor Associated with Nuclear Factor Kappa B and Yin Yang 1 in Human Hepatoma HepG2 Cells.
PLoS One. 2015; 10(8):e0136215 [PubMed
] Free Access to Full Article Related Publications
Multidrug resistance-associated protein 2 (MRP2) plays an important role in bile acid metabolism by transporting toxic organic anion conjugates, including conjugated bilirubin, glutathione, sulfate, and multifarious drugs. MRP2 expression is reduced in cholestatic patients and rodents. However, the molecular mechanism of MRP2 down-regulation remains elusive. In this report, we treated human hepatoma HepG2 cells with interleukin-18 (IL-18) and measured the expression of MRP2, nuclear factor kappa B (NF-κB), farnesoid X receptor (FXR), and the transcription factor Yin Yang 1 (YY1) by quantitative real-time quantitative polymerase chain reaction (PCR) and western blotting. We found that expression of MRP2 was repressed by IL-18 at both the mRNA and protein levels in a dose- and time-dependent manner. Furthermore, the activated NF-κB pathway increased YY1 and reduced FXR. These changes were all attenuated in HepG2 cells with knockdown of the NF-κB subunit, p65. The reduced expression of FXR and MRP2 in HepG2 cells that had been caused by IL-18 treatment was also attenuated by YY1 knockdown. We further observed significantly elevated IL-18, NF-κB, and YY1 expression and decreased FXR and MRP2 expression in bile duct-ligated Sprague Dawley rat livers. Chromatin immunoprecipitation assays also showed that FXR bound to the promoter region in MRP2 was less abundant in liver extracts from bile duct-ligated rats than sham-operated rats. Our findings indicate that IL-18 down-regulates MRP2 expression through the nuclear receptor FXR in HepG2 cells, and may be mediated by NF-κB and YY1.
Kjersem JB, Thomsen M, Guren T, et al.AGXT and ERCC2 polymorphisms are associated with clinical outcome in metastatic colorectal cancer patients treated with 5-FU/oxaliplatin.
Pharmacogenomics J. 2016; 16(3):272-9 [PubMed
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The objective of the study was to investigate whether specific single nucleotide polymorphisms (SNPs) with influence on drug transport, biotransformation and repair mechanisms are associated with treatment outcome and toxicity in metastatic colorectal cancer (mCRC). We genotyped blood samples from 519 mCRC patients treated with first-line 5-fluorouracil and oxaliplatin +/- cetuximab for 17 SNPs in 10 genes involved in membrane transport (ABCC1 and ABCC2), drug biotransformation (GSTP1 and AGXT) and DNA repair (ERCC1, ERCC2, XRCC1, XRCC3, XPG and MSH6). The AGXT-rs34116584 and the ERCC2-rs238406 polymorphisms were significantly associated with progression-free survival (P=0.002 and P=0.001, respectively). Associations between 18 toxicity variables and SNPs were identified, although none were significant after Bonferroni correction for multiple comparisons. The study identified SNPs of potential use as markers of clinical outcome in oxaliplatin-treated mCRC patients. If validated in other studies, they could improve the selection of therapy in mCRC.
Lee SH, Nam HJ, Kang HJ, et al.Valproic acid suppresses the self-renewal and proliferation of head and neck cancer stem cells.
Oncol Rep. 2015; 34(4):2065-71 [PubMed
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Emerging evidence suggests that cancer cells present profound epigenetic alterations in addition to featuring classic genetic mutations. Valproic acid (VPA), a histone deacetylase inhibitor, can potently inhibit tumor growth and induce differentiation. However, the effect and underlying mechanism of VPA on head and neck squamous cell carcinoma (HNSCC) cancer stem cells (CSCs) remain unclear. In the present study we investigated the effects of VPA on the characteristics of HNSCC CSCs in vitro and in vivo. As a result, VPA inhibited the self-renewal abilities of HNSCC CSCs during two serial passages and decreased the expression of stem cell markers, such as Oct4, Sox2 and CD44. VPA also potentiated the cytotoxic effect of cisplatin by suppressing the ABCC2 and ABCC6 transporters as well as by inducing caspase-mediated apoptosis. In addition, the combination of VPA and cisplatin attenuated tumor growth and induced apoptosis in a xenograft model. Our results suggest that VPA might be a potential therapeutic strategy in combination with conventional cisplatin for HNSCC patients by elimination of CSC traits.
Kopp TI, Andersen V, Tjonneland A, Vogel UPolymorphisms in ATP-binding cassette transporter genes and interaction with diet and life style factors in relation to colorectal cancer in a Danish prospective case-cohort study.
Scand J Gastroenterol. 2015; 50(12):1469-81 [PubMed
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BACKGROUND AND AIMS: The ATP-binding cassette (ABC) transporter family transports various molecules across the enterocytes in the gut protecting the intestine against potentially harmful substances. Moreover, ABC transporters are involved in mucosal immune defence through interaction with cytokines. The study aimed to assess whether polymorphisms in ABCB1, ABCC2 and ABCG2 were associated with risk of colorectal cancer (CRC) and to investigate gene-environment (dietary factors, smoking and use of non-steroidal anti-inflammatory drugs) and gene-gene interactions between previously studied polymorphisms in IL1B and IL10 and ABC transporter genes in relation to CRC risk.
MATERIALS AND METHODS: We used a Danish prospective case-cohort study of 1010 CRC cases and 1829 randomly selected participants from the Danish Diet, Cancer and Health cohort. Incidence rate ratios were calculated based on Cox' proportional hazards model.
RESULTS: None of the polymorphisms were associated with CRC, but ABCB1 and ABCG2 haplotypes were associated with risk of CRC. ABCB1/rs1045642 interacted with intake of cereals and fiber (p-Value for interaction (P(int)) = 0.001 and 0.01, respectively). In a three-way analysis, both ABCB1/rs1045642 and ABCG2/rs2231137 in combination with IL10/rs3024505 interacted with fiber intake in relation to risk of CRC (P(int) = 0.0007 and 0.009).
CONCLUSIONS: Our results suggest that the ABC transporters P-glycoprotein/multidrug resistance 1 and BRCP, in cooperation with IL-10, are involved in the biological mechanism underlying the protective effect of fiber intake in relation to CRC. These results should be replicated in other cohorts to rule out chance findings.
Wang H, Qian Z, Zhao H, et al.CSN5 silencing reverses sorafenib resistance of human hepatocellular carcinoma HepG2 cells.
Mol Med Rep. 2015; 12(3):3902-8 [PubMed
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Hepatocellular carcinoma (HCC) is one of the most common tumor types, and is the third leading cause of cancer mortalities worldwide. A large number of patients with HCC are diagnosed at a late stage when the curative treatment of surgical resection and liver transplantation are no longer applicable. Sorafenib has been proved to improve overall survival in advanced HCC; however, drug resistance is common. The present study reported that the CSN5 is correlated with sorafenib resistance of the HCC cell line HepG2/S. Following silencing of CSN5, resistance to sorafenib was reversed, and multi-drug‑resistance proteins, including as adenosine triphosphate binding cassette (ABC)B1, ABCC2 and ABCG2 as well as CDK6, cyclin D1 and B‑cell lymphoma 2 were downregulated. In addition, it was demonstrated that the integrin beta-1, transforming growth factor‑β1 and nuclear factor‑κB pathways were modified by CSN5.
Wallerek S, Sørensen JBBiomarkers for efficacy of adjuvant chemotherapy following complete resection in NSCLC stages I-IIIA.
Eur Respir Rev. 2015; 24(136):340-55 [PubMed
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Biomarkers may be useful when deciding which nonsmall cell lung cancer (NSCLC) patients may benefit from adjuvant chemotherapy following complete resection and which chemotherapeutic agents may be used preferably in individual patients in order to maximise survival. A literature search covering the period from 2003 to May, 2014 was conducted using PubMed and the following search terms: "non-small cell lung cancer", "NSCLC", "adjuvant chemotherapy", "randomized", "randomised", "biomarkers", "prognostic", "predictive". This review focuses on current knowledge of biomarkers for prognosis or efficacy of adjuvant treatment following complete resection in stage I-IIIA NSCLC patients. This review includes results on 18 different biomarkers and five gene profiles. A statistically significant prognostic impact was reported for: iNTR, TUBB3, RRM1, ERCC1, BRCA1, p53, MRP2, MSH2, TS, mucin, BAG-1, pERK1/2, pAkt-1, microRNA, TopIIA, 15-gene profile, 92-gene profile, 31-gene profile and 14-gene profile. A statistically significant predictive impact was reported for: ERCC1, p53, MSH2, p27, TUBB3, PARP1, ATM, 37-gene profile, 31-gene profile, 15-gene profile and 92-gene profile. Uncertainties regarding the optimal analysis method and cut-off levels for the individual markers may blur the prognostic or predictive signals. None of the possible predictive markers have been validated in prospective trials. Thus, there are no biomarkers ready to use in an adjuvant setting in NSCLC.
Vulsteke C, Pfeil AM, Maggen C, et al.Clinical and genetic risk factors for epirubicin-induced cardiac toxicity in early breast cancer patients.
Breast Cancer Res Treat. 2015; 152(1):67-76 [PubMed
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Anthracycline-induced cardiotoxicity (ACT) is a well-known serious adverse drug reaction leading to substantial morbidity. The purpose of this study was to assess ACT occurrence and clinical and genetic risk factors in early breast cancer patients. In 6 genes of interest (ABCC1, ABCC2, CYBA, NCF4, RAC2, SLC28A3), 10 single nucleotide polymorphisms (SNPs) involved in ACT were selected based on a literature search. Eight hundred and seventy-seven patients treated between 2000 and 2010 with 3-6 cycles of (neo) adjuvant 5-fluorouracil, epirubicin and cyclophosphamide (FEC) were genotyped for these SNPs using Sequenom MassARRAY. Main outcome measures were asymptomatic decrease of left ventricular ejection fraction (LVEF) > 10 % and cardiac failure grade 3-5 (CTCAE 4.0). To evaluate the impact of these 10 SNPs as well as clinical factors (age, relative dose intensity of epirubicin, left-sided radiotherapy, occurrence of febrile neutropenia, and planned and received cycles of epirubicin) on decrease of LVEF and cardiac failure, we performed uni- and multivariable logistic regression analysis. Additionally, exploratory analyses including 11 additional SNPs related to the metabolism of anthracyclines were performed. After a median follow-up of 3.62 years (range 0.40-9.60), a LVEF decline of > 10 % occurred in 153 patients (17.5 %) and cardiac failure in 16 patients (1.8 %). In multivariable analysis, six cycles of FEC compared to three cycles received and heterozygous carriers of the rs246221 T-allele in ABCC1 relative to homozygous carriers of the T-allele were significantly associated with LVEF decline of > 10 % (OR 1.3, 95 % CI 1.1-1.4, p < 0.001 and OR 1.6, 95 % CI 1.1-2.3, p = 0.02). Radiotherapy for left-sided breast cancer was associated with cardiac failure (OR 3.7, 95 % CI 1.2-11.5, p 0.026). The other 9 SNPs and clinical factors tested were not significantly associated. In our exploratory analysis, no other SNPs related to anthracycline metabolism were retained in the multivariate model for prediction of LVEF decline. ACT in breast cancer patients is related to number of received cycles of epirubicin and left-sided radiotherapy. Additional studies should be performed to independently confirm the potential association between rs246221 in ABCC1 and LVEF.
Skrypek N, Vasseur R, Vincent A, et al.The oncogenic receptor ErbB2 modulates gemcitabine and irinotecan/SN-38 chemoresistance of human pancreatic cancer cells via hCNT1 transporter and multidrug-resistance associated protein MRP-2.
Oncotarget. 2015; 6(13):10853-67 [PubMed
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Pancreatic adenocarcinoma (PDAC) is one of the most deadly cancers because of a lack of early diagnostic markers and efficient therapeutics. The fluorinated analog of deoxycytidine, gemcitabine and emerging FOLFIRINOX protocol (5-fluorouracil (5-FU), irinotecan/SN-38, oxaliplatin and leucovorin) are the main chemotherapies to treat PDAC. The ErbB2/HER2 oncogenic receptor is commonly overexpressed in PDAC. In this context, we aimed to decipher the ErbB2-mediated mechanisms of chemoresistance to the two main chemotherapy protocols used to treat PDAC.ErbB2 knocking down (KD) in CAPAN-1 and CAPAN-2 cells led to an increased sensitivity to gemcitabine and an increased resistance to irinotecan/SN-38 both in vitro and in vivo (subcutaneous xenografts) This was correlated to an increase of hCNT1 and hCNT3 transporters and ABCG2, MRP1 and MRP2 ATP-binding cassette transporters expression and resistance to cell death. We also show that MRP2 is repressed following activation of JNK, Erk1/2 and NF-κB pathways by ErbB2. Finally, in datasets of human PDAC samples, ErbB2 and MRP2 expression was conversely correlated. Altogether, we propose that ErbB2 mediates several intracellular mechanisms linked to PDAC cell chemoresistance that may represent potential targets in order to ameliorate chemotherapy response and allow stratification of patients eligible for either gemcitabine or FOLFIRINOX treatment.
BACKGROUND: This study aimed to determine whether single nucleotide polymorphisms (SNPs) in genes involved in DNA repair or metabolism of taxanes or platinum could predict toxicity or response to first-line chemotherapy in ovarian cancer.
METHODS: Twenty-six selected SNPs in 18 genes were genotyped in 322 patients treated with first-line paclitaxel-carboplatin or carboplatin mono-therapy. Genotypes were correlated with toxicity events (anemia, neutropenia, thrombocytopenia, febrile neutropenia, neurotoxicity), use of growth factors and survival.
RESULTS: The risk of anemia was increased for variant alleles of rs1128503 (ABCB1, C > T; p = 0.023, OR = 1.71, 95% CI = 1.07-2.71), rs363717 (ABCA1, A > G; p = 0.002, OR = 2.08, 95% CI = 1.32-3.27) and rs11615 (ERCC1, T > C; p = 0.031, OR = 1.61, 95% CI = 1.04-2.50), while it was decreased for variant alleles of rs12762549 (ABCC2, C > G; p = 0.004, OR = 0.51, 95% CI = 0.33-0.81). Likewise, increased risk of thrombocytopenia was associated with rs4986910 (CYP3A4, T > C; p = 0.025, OR = 4.99, 95% CI = 1.22-20.31). No significant correlations were found for neurotoxicity. Variant alleles of rs2073337 (ABCC2, A > G; p = 0.039, OR = 0.60, 95% CI = 0.37-0.98), rs1695 (ABCC1, A > G; p = 0.017, OR = 0.55, 95% CI 0.33-0.90) and rs1799793 (ERCC2, G > A; p = 0.042, OR = 0.63, 95% CI 0.41-0.98) associated with the use of colony stimulating factors (CSF), while rs2074087 (ABCC1, G > C; p = 0.011, OR = 2.09, 95% CI 1.18-3.68) correlated with use of erythropoiesis stimulating agents (ESAs). Homozygous carriers of the rs1799793 (ERCC2, G > A) G-allele had a prolonged platinum-free interval (p = 0.016).
CONCLUSIONS: Our data reveal significant correlations between genetic variants of transport, hepatic metabolism, platinum related detoxification or DNA damage repair and toxicity or outcome in ovarian cancer.
The overall goal of this study was to provide evidence for the clinical validity of nine genetic variants in five genes previously associated with irinotecan neutropenia and pharmacokinetics. Variants associated with absolute neutrophil count (ANC) nadir and/or irinotecan pharmacokinetics in a discovery cohort of cancer patients were genotyped in an independent replication cohort of 108 cancer patients. Patients received single-agent irinotecan every 3 weeks. For ANC nadir, we replicated UGT1A1*28, UGT1A1*93 and SLCO1B1*1b in univariate analyses. For irinotecan area under the concentration-time curve (AUC0-24), we replicated ABCC2 -24C>T; however, ABCC2 -24C>T only predicted a small fraction of the variance. For SN-38 AUC0-24 and the glucuronidation ratio, we replicated UGT1A1*28 and UGT1A1*93. In addition to UGT1A1*28, this study independently validated UGT1A1*93 and SLCO1B1*1b as new predictors of irinotecan neutropenia. Further demonstration of their clinical utility will optimize irinotecan therapy in cancer patients.
Reichwagen A, Ziepert M, Kreuz M, et al.Association of NADPH oxidase polymorphisms with anthracycline-induced cardiotoxicity in the RICOVER-60 trial of patients with aggressive CD20(+) B-cell lymphoma.
Pharmacogenomics. 2015; 16(4):361-72 [PubMed
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AIM: To identify gene variants responsible for anthracycline-induced cardiotoxicity.
PATIENTS & METHODS: Polymorphisms of the NADPH oxidase subunits and of the anthracycline transporters ABCC1, ABCC2 and SLC28A3 were genotyped in elderly patients (61-80 years) treated for aggressive CD20(+) B-cell lymphomas with CHOP-14 with or without rituximab and followed up for 3 years.
RESULTS: The accumulation of RAC2 subunit genotypes TA/AA among cases was statistically significant upon adjustment for gender, age and doxorubicin dose in a multivariate logistic regression analysis (OR: 2.3, p = 0.028; univariate: OR: 1.8, p = 0.077). RAC2 and CYBA genotypes were significantly associated with anthracycline-induced cardiotoxicity in a meta-analysis of this and a similar previous study.
CONCLUSION: Our results support the theory that NADPH oxidase is involved in anthracycline-induced cardiotoxicity. Original submitted 9 July 2014; Revision submitted 19 December 2014.
Development of colorectal cancer (CRC) may result from a dysfunctional interplay between diet, gut microbes and the immune system. The ABC transport proteins ABCB1 (P-glycoprotein, Multidrug resistance protein 1, MDR1), ABCC2 (MRP2) and ABCG2 (BCRP) are involved in transport of various compounds across the epithelial barrier. Low mRNA level of ABCB1 has previously been identified as an early event in colorectal carcinogenesis (Andersen et al., PLoS One. 2013 Aug 19;8(8):e72119). ABCC2 and ABCG2 mRNA levels were assessed in intestinal tissue from 122 CRC cases, 106 adenoma cases (12 with severe dysplasia, 94 with mild-moderate dysplasia) and from 18 controls with normal endoscopy. We found significantly higher level of ABCC2 in adenomas with mild to moderate dysplasia and carcinoma tissue compared to the levels in unaffected tissue from the same individual (P = 0.037, P = 0.037, and P<0.0001) and in carcinoma and distant unaffected tissue from CRC cases compared to the level in the healthy individuals (P = 0.0046 and P = 0.036). Furthermore, ABCG2 mRNA levels were significantly lower in adenomas and carcinomas compared to the level in unaffected tissue from the same individuals and compared to tissue from healthy individuals (P<0.0001 for all). The level of ABCB2 in adjacent normal tissue was significantly higher than in tissue from healthy individuals (P = 0.011). In conclusion, this study found that ABCC2 and ABCG2 expression levels were altered already in mild/moderate dysplasia in carcinogenesis suggesting that these ABC transporters are involved in the early steps of carcinogenesis as previously reported for ABCB1. These results suggest that dysfunctional transport across the epithelial barrier may contribute to colorectal carcinogenesis.