Human Equilibrative Nucleoside Transporter Research Articles

Identification of Structural and Molecular Features Involved in the Transport of 3'-Deoxy-Nucleoside Analogs by Human Equilibrative Nucleoside Transporter 3.

Combination antiretroviral drug treatments depend on 3′-deoxy-nucleoside analogs such as 3′-azido-3′-deoxythymidine (AZT) and 2′3′-dideoxyinosine (DDI). Despite being effective in inhibiting human immunodeficiency virus replication, these drugs produce a range of toxicities, including myopathy, pancreatitis, neuropathy, and lactic acidosis, that are generally considered as sequelae to mitochondrial damage. Although cell surface–localized nucleoside transporters, such as human equilibrative nucleoside transporter 2 (hENT2) and human concentrative nucleoside transporter 1 (hCNT1), are known to increase the carrier-mediated uptake of 3′-deoxy-nucleoside analogs into cells, another ubiquitously expressed intracellular nucleoside transporter (namely, hENT3) has been implicated in the mitochondrial transport of 3′-deoxy-nucleoside analogs. Using site-directed mutagenesis, generation of chimeric hENTs, and 3H-permeant flux measurements in mutant/chimeric RNA–injected Xenopus oocytes, here we identified the molecular determinants of hENT3 that dictate membrane translocation of 3′-deoxy-nucleoside analogs. Our findings demonstrated that whereas hENT1 had no significant transport activity toward 3′-deoxy-nucleoside analogs, hENT3 was capable of transporting 3′-deoxy-nucleoside analogs similar to hENT2. Transport analyses of hENT3-hENT1 chimeric constructs demonstrated that the N-terminal half of hENT3 is primarily responsible for the hENT3–3′-deoxy-nucleoside analog interaction. In addition, mutagenic studies identified that 225D and 231L in the N-terminal half of hENT3 partially contribute to the ability of hENT3 to transport AZT and DDI. The identification of the transporter segment and amino acid residues that are important in hENT3 transport of 3′-deoxy-nucleoside analogs may present a possible mechanism for overcoming the adverse toxicities associated with 3′-deoxy-nucleoside analog treatment and may guide rational development of novel nucleoside analogs.

Efficacy of low-dose gemcitabine chemotherapy on pancreatic cancer patients with mutant of solute carrier family 29, member 1 gene T1288A

Objective To observe the efficacy and adverse effects of low-dose gemcitabine chemotherapy in pancreatic cancer patients with mutant of solute carrier family 29, member 1 (SLC29A1) gene T1288A. Methods A total of 72 pancreatic cancer patients with mutant of SLC29A1 gene T1288A were included in this study. They were randomly assigned to the experimental group (low-dose gemcitabine, 600 mg/m2) and the control group (standard-dose gemcitabine, 1 000 mg/m2), both groups included 36 patients. The curative effect and adverse reactions were observed and evaluated. Results There was no significant difference of the efficacy between the experimental group and the control group. The incidences of leukopenia, thrombocytopenia, erythrocyte reduction, vomiting, liver damage, diarrhea, rash and itching, the incidence of influenza-like symptoms were 3 (8.3%), 3 (8.3%), 4 (11.1%), 6 (16.7%), 2 (5.6%), 3 (8.3%), 1 (2.8%), 1 (2.8%) in the group of low-dose gemcitabine chemotherapy and 12 (33.3%), 15 (41.7%), 13 (36.1%), 20 (55.6%), 2 (5.6%), 4 (11.1%), 1 (2.8%), 1 (2.8%) in the group of standard-dose gemcitabine chemotherapy. The adverse effects indexes which leukopenia (P=0.009), thrombocytopenia (P=0.001), erythrocyte reduction (P=0.013), and vomiting (P=0.001) were statistically significant between two groups. There was no statistically significant difference between the two groups in June and 1 year survival by survival analysis. Conclusion For pancreatic cancer patients with mutant of SLC29A1 gene T1288A, there is a similar effect and less incidence of adverse effects in the experimental group when compared to the control group. Key words: Gemcitabine; Pancreatic cancer; Solute carrier family 29, member 1 gene; Human equilibrative nucleoside transporter 1

Expression of dihydropyrimidine dehydrogenase (DPD) and hENT1 predicts survival in pancreatic cancer

ABSTRACTBackgroundDihydropyrimidine dehydrogenase (DPD) tumour expression may provide added value to human equilibrative nucleoside transporter-1 (hENT1) tumour expression in predicting survival following pyrimidine-based adjuvant chemotherapy.MethodsDPD and hENT1 immunohistochemistry and scoring was completed on tumour cores from 238 patients with pancreatic cancer in the ESPAC-3(v2) trial, randomised to either postoperative gemcitabine or 5-fluorouracil/folinic acid (5FU/FA).ResultsDPD tumour expression was associated with reduced overall survival (hazard ratio, HR = 1.73 [95% confidence interval, CI = 1.21–2.49], p = 0.003). This was significant in the 5FU/FA arm (HR = 2.07 [95% CI = 1.22–3.53], p = 0.007), but not in the gemcitabine arm (HR = 1.47 [0.91–3.37], p = 0.119). High hENT1 tumour expression was associated with increased survival in gemcitabine treated (HR = 0.56 [0.38–0.82], p = 0.003) but not in 5FU/FA treated patients (HR = 1.19 [0.80–1.78], p = 0.390). In patients with low hENT1 tumour expression, high DPD tumour expression was associated with a worse median [95% CI] survival in the 5FU/FA arm (9.7 [5.3–30.4] vs 29.2 [19.5–41.9] months, p = 0.002) but not in the gemcitabine arm (14.0 [9.1–15.7] vs. 18.0 [7.6–15.3] months, p = 1.000). The interaction of treatment arm and DPD expression was not significant (p = 0.303), but the interaction of treatment arm and hENT1 expression was (p = 0.009).ConclusionDPD tumour expression was a negative prognostic biomarker. Together with tumour expression of hENT1, DPD tumour expression defined patient subgroups that might benefit from either postoperative 5FU/FA or gemcitabine.

Combined treatment of gemcitabine with indole-3-carbinol or metformin on drug efficacy in pancreatic cancer cell lines: The role of human equilibrative nucleoside transporters

Combined treatment of gemcitabine with indole-3-carbinol or metformin on drug efficacy in pancreatic cancer cell lines: The role of human equilibrative nucleoside transporters

Pathological and Molecular Aspects to Improve Endoscopic Ultrasonography-Guided Fine-Needle Aspiration From Solid Pancreatic Lesions.

Endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) has been applied to pancreatic lesions since the 1990s, and its use is now widespread. Improvements in endoscopic devices and sampling techniques have resulted in excellent diagnostic ability for solid pancreatic lesions. However, clinical improvements alone are not responsible for it; pathological aspects have also played important roles. Rapid on-site evaluation minimizes endoscopic procedures, although its value at improving the diagnostic ratio is still debated. Diagnostic efficacy differs by sample preparations (direct smear, cytospin, liquid-based cytology, cell block, and biopsy) and by staining methods (Papanicoloau, Diff-Quik, hematoxylin-eosin, and Giemsa). Several immunocytochemistry protocols aid in diagnosing epithelial components with cytological atypia and in differentiating various tumor types. One cytopathology diagnostic system is telecytology, which uses transmitted digital images and enables real-time diagnosis of EUS-FNA samples by expert cytologists at remote locations. However, EUS-FNA samples are useful for more than just diagnoses, as molecular analysis of these samples allows the identification of prognostic markers, such as genetic alterations in K-ras and EGFR. Expression of drug-metabolizing enzymes, human equilibrative nucleoside transporter 1, correlates with the response to gemcitabine-based chemotherapy. These pathology efforts have enhanced the diagnostic efficacy of EUS-FNA, thereby leading to better outcomes for patients with pancreatic diseases.

PH Sensing mechanism of human equilibrative nucleoside transporter 3 involved in mitochondrial transport of nucleoside analog drugs

pH Sensing mechanism of human equilibrative nucleoside transporter 3 involved in mitochondrial transport of nucleoside analog drugs

Precision design of nanomedicines to restore gemcitabine chemosensitivity for personalized pancreatic ductal adenocarcinoma treatment

Low chemosensitivity considerably restricts the therapeutic efficacy of gemcitabine (GEM) in pancreatic cancer treatment. Using immunohistochemical evaluation, we investigated that decreased expression of human equilibrative nucleoside transporter-1 (hENT1, which is the major GEM transporter across cell membranes) and increased expression of ribonucleotide reductase subunit 2 (RRM2, which decreases the cytotoxicity of GEM) was associated with low GEM chemosensitivity. To solve these problems, we employed a nanomedicine-based formulation of cationic liposomes for co-delivery of GEM along with siRNA targeting RRM2. Due to the specific endocytic uptake mechanism of nanocarriers and gene-silencing effect of RRM2 siRNA, this nanomedicine formulation significantly increased GEM chemosensitivity in tumor models of genetically engineered Panc1 cells with low hENT1 or high RRM2 expression. Moreover, in a series of patient-derived cancer cells, we demonstrated that the therapeutic benefits of the nanomedicine formulations were associated with the expression levels of hENT1 and RRM2. In summary, we found that the essential factors of GEM chemosensitivity were the expression levels of hENT1 and RRM2, and synthesized nanoformulations can overcome these problems. This unique design of nanomedicine not only provides a universal platform to enhance chemosensitivity but also contributes to the precision design and personalized treatment in nanomedicine.

Metabolomic prediction of treatment outcome in pancreatic ductal adenocarcinoma patients receiving gemcitabine.

Resistance to gemcitabine remains a key challenge in the treatment of pancreatic ductal adenocarcinoma (PDAC), necessitating the constant search for effective strategies for a priori prediction of clinical outcome. While the existing studies focused on aberration of drug disposition genes and proteins as molecular predictors of gemcitabine treatment outcomes, the metabolic aberration associated with chemoresistance in clinical PDAC has been neglected. This exploratory study investigated the potential role of tissue metabolomics in characterizing the clinical treatment outcome of gemcitabine therapy. Surgically resected tumors from PDAC patients who underwent gemcitabine-based adjuvant chemotherapy (n = 25) were subjected to metabotyping using gas chromatography/time-of-flight mass spectrometry (GC/TOFMS). A partial least-squares discriminant analysis (PLS-DA) model clearly distinguished patients who had favorable survival [overall survival (OS) > 24 months] from those who exhibited poorer survival (OS < 16 months) (Q 2 = 0.302). Receiver-operating characteristic analysis demonstrated the robustness of the PLS-DA model with an area under the curve of 1. PLS-DA revealed 19 marker metabolites (e.g., lactic acid, proline, and pyroglutamate) that shed insights into the chemoresistance of gemcitabine in PDAC. Particularly, tissue levels of lactic acid complemented transcript expression levels of human equilibrative nucleoside transporter 1 in distinguishing patients according to their overall survival. This work established proof-of-principle for GC/TOFMS-based global metabotyping of PDAC and laid the foundation for future discovery of metabolic biomarkers predictive of gemcitabine resistance in PDAC chemotherapy.

The Role of Platelet-Derived ADP and ATP in Promoting Pancreatic Cancer Cell Survival and Gemcitabine Resistance.

Platelets have been demonstrated to be vital in cancer epithelial-mesenchymal transition (EMT), an important step in metastasis. Markers of EMT are associated with chemotherapy resistance. However, the association between the development of chemoresistance, EMT, and the contribution of platelets to the process, is still unclear. Here we report that platelets regulate the expression of (1) human equilibrative nucleoside transporter 1 (hENT1) and (2) cytidine deaminase (CDD), markers of gemcitabine resistance in pancreatic cancer. Human ENT1 (hENT1) is known to enable cellular uptake of gemcitabine while CDD deactivates gemcitabine. Knockdown experiments demonstrate that Slug, a mesenchymal transcriptional factor known to be upregulated during EMT, regulates the expression of hENT1 and CDD. Furthermore, we demonstrate that platelet-derived ADP and ATP regulate Slug and CDD expression in pancreatic cancer cells. Finally, we demonstrate that pancreatic cancer cells express the purinergic receptor P2Y12, an ADP receptor found mainly on platelets. Thus ticagrelor, a P2Y12 inhibitor, was used to examine the potential therapeutic effect of an ADP receptor antagonist on cancer cells. Our data indicate that ticagrelor negated the survival signals initiated in cancer cells by platelet-derived ADP and ATP. In conclusion, our results demonstrate a novel role of platelets in modulating chemoresistance in pancreatic cancer. Moreover, we propose ADP/ATP receptors as additional potential drug targets for treatment of pancreatic cancer.

Gemcitabine-Based Chemotherapy in Adrenocortical Carcinoma: A Multicenter Study of Efficacy and Predictive Factors.

Adrenocortical carcinoma (ACC) is rare and confers an unfavorable prognosis in advanced stages. Other than combination chemotherapy with cisplatin, etoposide, doxorubicin, and mitotane, the second- and third-line regimens are not well-established. Gemcitabine (GEM)-based chemotherapy was suggested in a phase 2 clinical trial with 28 patients. In other solid tumors, human equilibrative nucleoside transporter type 1 (hENT1) and/or ribonucleotide reductase catalytic subunit M1 (RRM1) expression have been associated with resistance to GEM. To assess the efficacy of GEM-based chemotherapy in ACC in a real-world setting and the predictive role of molecular parameters. Retrospective multicenter study. Referral centers of university hospitals. A total of 145 patients with advanced ACC were treated with GEM-based chemotherapy (132 with concomitant capecitabine). Formalin-fixed paraffin-embedded tumor material was available for 70 patients for immunohistochemistry. The main outcome measures were progression-free survival (PFS) and an objective response to GEM-based chemotherapy. The secondary objective was the predictive role of hENT1 and RRM1. The median PFS for the patient population was 12 weeks (range, 1 to 94). A partial response or stable disease was achieved in 4.9% and 25.0% of cases, with a median duration of 26.8 weeks. Treatment was generally well tolerated, with adverse events of grade 3 or 4 occurring in 11.0% of cases. No substantial effect of hENT1 and/or RRM1 expression was observed in response to GEM-based chemotherapy. GEM-based chemotherapy is a well-tolerated, but modestly active, regimen against advanced ACC. No reliable molecular predictive factors could be identified. Owing to the scarce alternative therapeutic options, GEM-based chemotherapy remains an important option for salvage treatment for advanced ACC.

Expression and purification of human and Saccharomyces cerevisiae equilibrative nucleoside transporters

Nucleosides play an essential role in the physiology of eukaryotes by acting as metabolic precursors in de novo nucleic acid synthesis and energy metabolism. Nucleosides also act as ligands for purinergic receptors. Equilibrative nucleoside transporters (ENTs) are polytopic integral membrane proteins that aid in regulating plasmalemmal flux of purine and pyrimidine nucleosides and nucleobases. ENTs exhibit broad substrate selectivity across different isoforms and utilize diverse mechanisms to drive substrate flux across membranes. However, the molecular mechanisms and chemical determinants of ENT-mediated substrate recognition, binding, inhibition, and transport are poorly understood. To determine how ENT-mediated transport occurs at the molecular level, greater chemical insight and assays employing purified protein are essential. This article focuses on the expression and purification of human ENT1, human ENT2, and Saccharomyces cerevisiae ScENT1 using novel expression and purification strategies to isolate recombinant ENTs. ScENT1, hENT1, and hENT2 were expressed in W303 Saccharomyces cerevisiae cells and detergent solubilized from the membrane. After detergent extraction, these ENTs were further purified using immobilized metal affinity chromatography and size exclusion chromatography. This effort resulted in obtaining quantities of purified protein sufficient for future biophysical analysis.

Molecular determinants of acidic pH-dependent transport of human equilibrative nucleoside transporter 3

Equilibrative nucleoside transporters (ENTs) translocate hydrophilic nucleosides across cellular membranes and are essential for salvage nucleotide synthesis and purinergic signaling. Unlike the prototypic human ENT members hENT1 and hENT2, which mediate plasma membrane nucleoside transport at pH 7.4, hENT3 is an acidic pH-activated lysosomal transporter partially localized to mitochondria. Recent studies demonstrate that hENT3 is indispensable for lysosomal homeostasis, and that mutations in hENT3 can result in a spectrum of lysosomal storage-like disorders. However, despite hENT3's prominent role in lysosome pathophysiology, the molecular basis of hENT3-mediated transport is unknown. Therefore, we sought to examine the mechanistic basis of acidic pH-driven hENT3 nucleoside transport with site-directed mutagenesis, homology modeling, and [3H]adenosine flux measurements in mutant RNA-injected Xenopus oocytes. Scanning mutagenesis of putative residues responsible for pH-dependent transport via hENT3 revealed that the ionization states of Asp-219 and Glu-447, and not His, strongly determined the pH-dependent transport permissible-impermissible states of the transporter. Except for substitution with certain isosteric and polar residues, substitution of either Asp-219 or Glu-447 with any other residues resulted in robust activity that was pH-independent. Dual substitution of Asp-219 and Glu-447 to Ala sustained pH-independent activity over a broad range of physiological pH (pH 5.5-7.4), which also maintained stringent substrate selectivity toward endogenous nucleosides and clinically used nucleoside drugs. Our results suggest a putative pH-sensing role for Asp-219 and Glu-447 in hENT3 and that the size, ionization state, or electronegative polarity at these positions is crucial for obligate acidic pH-dependent activity.

Astaxanthin inhibits gemcitabine-resistant human pancreatic cancer progression through EMT inhibition and gemcitabine resensitization.

Pancreatic cancer rapidly acquires resistance to chemotherapy resulting in its being difficult to treat. Gemcitabine is the current clinical chemotherapy strategy; however, owing to gemcitabine resistance, it is only able to prolong the life of patients with pancreatic cancer for a limited number of months. Understanding the underlying molecular mechanisms of gemcitabine resistance and selecting a suitable combination of agents for the treatment of pancreatic cancer is required. Astaxanthin (ASX) is able to resensitize gemcitabine-resistant human pancreatic cancer cells (GR-HPCCs) to gemcitabine. ASX was identified to upregulate human equilibrative nucleoside transporter 1 (hENT1) and downregulate ribonucleoside diphosphate reductase (RRM) 1 and 2 to enhance gemcitabine-induced cell death in GR-HPCCs treated with gemcitabine, and also downregulates TWIST1 and ZEB1 to inhibit the gemcitabine-induced epithelial-mesenchymal transition (EMT) phenotype in GR-HPCCs and to mediate hENT1, RRM1 and RRM2. Furthermore, ASX acts through the hypoxia-inducible factor 1α/signal transducer and activator of transcription 3 signaling pathway to mediate TWIST1, ZEB1, hENT1, RRM1 and RRM2, regulating the gemcitabine-induced EMT phenotype and gemcitabine-induced cell death. Co-treatment with ASX and gemcitabine in a tumor xenograft model induced by GR-HPCCs supported the in vitro results. The results of the present study provide a novel therapeutic strategy for the treatment of gemcitabine-resistant pancreatic cancer.

A predictive analysis of the SP120 and 10D7G2 antibodies for human equilibrative nucleoside transporter 1 (hENT1) in pancreatic ductal adenocarcinoma treated with adjuvant gemcitabine.

Expression of human equilibrative nucleoside transporter 1 (hENT1) in pancreatic ductal adenocarcinoma (PDAC) has been postulated to be a marker of sensitivity to gemcitabine. However, heterogeneity in the studies attempting to quantify hENT1 expression in patients with PDAC treated with gemcitabine has yielded inconclusive results that impede the adoption of hENT1 expression as a predictive biomarker. Tissue microarrays consisting of PDAC specimens from 227 patients acquired between 1987 and 2013 annotated with treatment and outcome information were subjected to staining with two antibodies for hENT1 (10D7G2 and SP120) on a single automated platform and scored by two independent pathologists blinded to treatment and outcome. The resultant scores were subjected to individual predictive disease‐specific survival analysis and to unsupervised hierarchical clustering to generate a multi‐marker classification. Tumour cell staining prevalence using either SP120 or 10D7G2 was predictive of gemcitabine sensitivity (p = 0.02; p = 0.01). When combined, three groups emerged, classified as SP120Low_10D7G2Low, SP120Low_10D7G2High, and SP120High_10D7G2High, in which adjuvant gemcitabine conferred median survival differences of 0.2, 0.8, and 1.5 (p = 0.76, p = 0.06, p = 0.01) years, respectively. These results were largely replicated in multivariable analysis with the P value for the SP120Low_10D7G2High cluster achieving statistical significance (p = 0.03). These data suggest that either antibody for hENT1 can be used to predict gemcitabine sensitivity in resected PDAC. However, using both antibodies adds valuable information that enables the stratification of patients who can expect to have a good, intermediate, and poor response to adjuvant gemcitabine.

Human equilibrative nucleoside transporter 1 gene expression is associated with gemcitabine efficacy in advanced leiomyosarcoma and angiosarcoma

Background:The expression of human equilibrative nucleoside transporter 1 (hENT1), the major gemcitabine transporter into cells, has been thoroughly investigated as a predictive marker of response to gemcitabine in pancreatic cancer and biliary tract cancers. Since gemcitabine is widely used in the treatment of leiomyosarcoma and angiosarcoma, we investigated the correlation between hENT1 expression and gemcitabine efficacy in these sarcoma subtypes.Methods:We retrospectively identified 71 patients affected by advanced angiosarcoma (26) or leiomyosarcoma (45) treated within five Italian referral centres for sarcoma; among them, 49 patients (15 angiosarcoma, 34 leiomyosarcoma) were treated with gemcitabine. All tumour samples were analysed for hENT1 expression by real-time PCR. Median 2–ΔCt value was used as the cutoff to dichotomise patients into ‘high’ expression and ‘low’ expression groups. Kaplan–Meier analysis was performed to estimate progression-free survival (PFS) and overall survival (OS).Results:We found a significant association between high hENT1 expression levels and favourable outcome in terms of PFS and OS compared to cases with low hENT1 expression in leiomyosarcoma treated with gemcitabine (PFS: 6.8 vs 3.2 months, P=0.004; OS: 14.9 vs 8.5 months, P=0.007). In addition, hENT1 overexpression correlated with a significant improvement in PFS (9.3 vs 4.5 months; P=0.02) and OS (20.6 vs 10.8 months; P=0.001) in angiosarcoma patients treated with gemcitabine.Conclusions:Our study suggests that higher hENT1 expression are associated to gemcitabine efficacy both in patients with advanced leiomyosarcoma and angiosarcoma.

Prognostic value of p21‐activated kinase 4 in resected pancreatic cancer

Resectable pancreatic cancer has a high recurrence rate after curative surgery. Biomarkers are needed for distinguishing patients who may benefit from curative resection. In this study, we sought to analyze the prognostic value of p21-activated kinase 1 (PAK1), p21-activated kinase 4 (PAK4), human equilibrative nucleoside transporter 1 (hENT1), and thymidylate synthase (TS) in surgically resected pancreatic ductal adenocarcinomas. A total of 160 pancreatic cancer patients who underwent surgery with curative intent were retrospectively reviewed. Tissue microarrays were constructed and immunohistochemical stains were performed for PAK1, PAK4, hENT1, and TS. The absence of PAK4 expression in pancreatic adenocarcinomas was associated with poorer histologic differentiation (p < 0.001), shorter overall survival [hazard ratio (HR) = 2.86, 95% confidence interval (CI) 1.43-5.71; p = 0.003], and disease-free survival (HR = 2.29, 95% CI: 1.11-4.74; p = 0.025) on univariate analyses. In addition, more frequent venous invasion and lymph node metastases were seen in PAK4-negative tumors although not statistically significant. PAK1, hENT1, and TS expression status did not have significant influences on patient survival. In conclusion, PAK4 of the markers tested in this study may be a potential prognostic biomarker for pancreatic adenocarcinomas.

Predictive value of hENT1 immunohistochemistry for gemcitabine-treated pancreatic cancer is antibody dependent.

e15746 Background: Pancreatic cancer (PC) continues to have poor outcomes, and biomarkers to guide individualized therapy are needed. Gemcitabine (GEM), a pyrimidine nucleoside, requires plasma membrane transporter proteins to enter cells, and deficiency of the human equilibrative nucleoside transporter 1 (hENT1) protein confers high-level GEM resistance in pre-clinical models. Furthermore, abundance of hENT in PC cells, as determined by immunohistochemistry (IHC), has been variably reported to be associated with improved survival in people with PC treated with GEM. The antibodies (Abs) used for IHC differ in targeted epitope, method of generation, and species of origin. The purpose of this review is to evaluate the contribution of anti-hENT1 Ab choice in finding a link between hENT1 expression and outcomes. Methods: We reviewed the published literature investigating relationships between hENT1 IHC tumor expression and survival in people with PC treated with GEM. Results: Eighteen studies were identified, using five distinct Abs (Table 1). We identified apparent differences in predictive value among Abs (Chi square test p = 0.065). All seven studies using the 10D7G2 Ab reported that high hENT1 expression is associated with significantly better outcomes in GEM-treated patients. Studies that used other anti-hENT1 Abs, in particular SP120 and 11337-1-AP, had lower rates of success. Pooled HRs and additional metrics will be presented. Conclusions: There is significant heterogeneity among studies evaluating the link between hENT1 expression and outcomes. hENT1 IHC with the 10D7G2 Ab is a strong and reproducible predictive marker for improved survival in people with PC treated with GEM. [Table: see text]

Predictive role of human equilibrative nucleoside transporter 1 in patients with pancreatic cancer treated by curative resection and gemcitabine-only adjuvant chemotherapy.

The predictive roles of human equilibrative nucleoside transporter 1 (hENT-1) in patients who undergo curative resection and adjuvant chemotherapy with gemcitabine alone have not been established. The present study retrospectively analyzed the clinical data from 101 consecutive patients who underwent curative resection and who received gemcitabine adjuvant chemotherapy for the treatment of pancreatic cancer at Kanagawa Cancer Center (Yokohama, Japan) between 2005 and 2014. The associations between the hENT-1 status and the survival and clinicopathological features of the patients were investigated. Of the 101 patients, 60 patients (59.4%) had high levels of hENT-1 expression. A significant association was observed between hENT-1 status and sex; however, for all the other clinicopathological parameters, including tumor and node stages, no differences were observed between the high and low hENT-1 expression groups. The median follow-up period of the present study was 67.3 months. Between the high and low hENT-1 expression groups, there was a statistically significant difference in the 5-year overall survival (OS) rates following surgery (20.6 and 8.9%, respectively; P=0.019). In addition, a significant difference was observed in the recurrence-free survival (RFS) rates at 5 years following surgery (P=0.049). hENT-1 status was one of the important predictive factors for OS and RFS in patients with pancreatic cancer who underwent curative resection followed by adjuvant chemotherapy with gemcitabine. Adjuvant chemotherapy with gemcitabine alone may be insufficient, particularly in patients with certain relevant risk factors.

Combined Analyses of hENT1, TS, and DPD Predict Outcomes of Borderline-resectable Pancreatic Cancer.

Predicting chemosensitivity to neoadjuvant chemoradiotherapy (NACRT) in pancreatic cancer is desired. The present study aimed to examine the relationship between intratumoral expression of human equilibrative nucleoside transporter 1 (hENT1), thymidylate synthase (TS), and dihydropyrimidine dehydrogenase (DPD) and the outcomes of NACRT with gemcitabine (GEM) combined with S-1 in patients with borderline-resectable pancreatic cancer (BRPC). Forty-seven patients who underwent NACRT with GEM plus S-1, following curative surgery, were recruited in our Institution between 2009 and 2012. Immunohistochemical expressions of hENT1, TS, and DPD in fine-needle aspiration (FNA) biopsies and resected specimens were examined. The correlation between these enzyme expressions and long-term outcome was analyzed. In 21 FNA specimens, no relationship between clinical responses to NACRT and long-term survival was found. However, in 47 resected specimens, patients were classified according to the number of favorable hENT1, TS, and DPD expression factors (hENT1 positive/TS negative/DPD negative). The presence of three favorable factors was strongly associated with improved partial response rates to NACRT (p=0.002). Patients with 2 or more favorable factors showed a significantly longer overall survival than the other patients (p=0.002). Combined expression analyses of hENT1, TS, and DPD may predict long-term outcomes in patients with BRPC after NACRT.

Prognostic Implications of Expression Profiling for Gemcitabine-Related Genes (hENT1, dCK, RRM1, RRM2) in Patients With Resectable Pancreatic Adenocarcinoma Receiving Adjuvant Chemotherapy.

The aim of this study was to examine the relevance of expression profiling of 4 genes involved in the action of gemcitabine among patients with pancreatic ductal-cell adenocarcinoma (PDAC). A group of 100 patients who underwent pancreatic resections for PDAC and received adjuvant chemotherapy with gemcitabine between 2007 and 2010 was identified. Expression of mRNAs for human equilibrative nucleoside transporter 1 (hENT1), ribonucleotide reductase subunits (RRM1, RRM2), and deoxycytidine kinase (dCK) was examined by quantitative real-time polymerase chain reaction, normalized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and dichotomized into groups of low and moderate/high expression levels grouped by tertiles. Significantly better median survival times were found for high/moderate expression levels of hENT1 (27.9 vs 12.4 months, P = 0.001) and dCK (19.7 vs 10.5 months, P = 0.003), as well as low expression of RRM1 (23.4 vs 11.4 months, P = 0.027). A Cox proportional hazards model identified low expression of hENT1 (hazard ratio [HR], 3.38; 95% confidence intervals [CI], 2.28-10.50) and dCK (HR, 2.24; 95% CI, 1.63-3.39), and high/moderate levels of RRM1 (HR, 1.65; 95% CI, 1.23-2.45) as negative prognostic factors. Expression of hENT, RRM1, and dCK genes provides important prognostic information for PDAC patients treated with adjuvant gemcitabine.