Human equilibrative nucleoside transporter 1 and carcinoma of the ampulla of Vater: expression differences in tumour histotypes

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 effect of hENT1, dCK and HuR expression by morphological type in periampullary adenocarcinoma, including pancreatic cancer

BACKGROUND

Putative biomarkers of gemcitabine response have been extensively studied in pancreatic cancer, but less so in other types of periampullary adenocarcinoma. The most studied biomarker is human equilibrative nucleoside transporter 1 (hENT1), and the activating enzyme deoxycytidine kinase (dCK) has also been linked to treatment response. The RNA-binding protein human antigen R (HuR) has been demonstrated to confer increased dCK levels in vitro and to predict gemcitabine response in vivo. Here, we investigated the prognostic impact of hENT1, dCK and HuR in pancreatobiliary (PB) and intestinal (I) type periampullary cancers, respectively.

MATERIAL AND METHODS

Immunohistochemical expression of hENT1, dCK and HuR was evaluated in tissue microarrays with all primary tumours and 103 paired lymph node metastases from a consecutive retrospective cohort of 175 patients with resected periampullary adenocarcinomas.

RESULTS

In patients with PB-type tumours, neither hENT1 nor dCK expression was prognostic. A high HuR cytoplasmic/nuclear ratio was associated with a significantly reduced five-year overall survival (OS) in patients receiving adjuvant gemcitabine (HR 2.07, 95% CI 1.03-4.17) but not in untreated patients (pinteraction = 0.028). In patients with I-type tumours receiving adjuvant chemotherapy, high dCK expression was significantly associated with a prolonged recurrence-free survival (RFS) (HR 0.09, 95% CI 0.01-0.73, pinteraction = 0.023). Furthermore, HuR expression was associated with a prolonged OS and RFS in unadjusted but not in adjusted analysis and hENT1 expression was an independent predictor of a prolonged RFS (HR 0.24, 95% CI 0.10-0.59), regardless of adjuvant treatment.

CONCLUSION

hENT1 expression is a favourable prognostic factor in I-type, but not in PB-type tumours. High dCK expression is a favourable prognostic factor in patients with I-type tumours receiving adjuvant treatment and a high cytoplasmic/nuclear HuR ratio is a negative prognostic factor in gemcitabine-treated PB-type tumours. Morphological subtype should always be considered in biomarker studies on periampullary cancer.

Nucleoside transporter proteins as biomarkers of drug responsiveness and drug targets

Nucleoside and nucleobase analogs are currently used in the treatment of solid tumors, lymphoproliferative diseases, viral infections such as hepatitis and AIDS, and some inflammatory diseases such as Crohn. Two gene families are implicated in the uptake of nucleosides and nucleoside analogs into cells, SCL28 and SLC29. The former encodes hCNT1, hCNT2, and hCNT3 proteins. They translocate nucleosides in a Na⁺ coupled manner with high affinity and some substrate selectivity, being hCNT1 and hCNT2 pyrimidine- and purine-preferring, respectively, and hCNT3 a broad selectivity transporter. SLC29 genes encode four members, being hENT1 and hENT2 the only two which are unequivocally implicated in the translocation of nucleosides and nucleobases (the latter mostly via hENT2) at the cell plasma membrane. Some nucleoside-derived drugs can also interact with and be translocated by members of the SLC22 gene family, particularly hOCT and hOAT proteins. Inter-individual differences in transporter function and perhaps, more importantly, altered expression associated with the disease itself might modulate the transporter profile of target cells, thereby determining drug bioavailability and action. Drug transporter pharmacology has been periodically reviewed. Thus, with this contribution we aim at providing a state-of-the-art overview of the clinical evidence generated so far supporting the concept that these membrane proteins can indeed be biomarkers suitable for diagnosis and/or prognosis. Last but not least, some of these transporter proteins can also be envisaged as drug targets, as long as they can show “transceptor” functions, in some cases related to their role as modulators of extracellular adenosine levels, thereby providing a functional link between P1 receptors and transporters.

Carcinoma of the ampulla of Vater: morphological and immunophenotypical classification predicts overall survival

OBJECTIVES

The objective of the study was to verify if histopathological differentiation of ampullary carcinoma after surgical resection may be related to survival.

METHODS

The prognostic role of an accurate histological and immunohistochemical classification has been investigated in a multicentric series of carcinoma of the ampulla of Vater. Immunohistochemical expression of cytokeratin 7 (CK7) and CK20 were analyzed in the different morphological histotypes of ampullary cancers, and results were compared with overall survival.

RESULTS

Of 72 ampullary cancers, 48.6% were classified as pancreaticobiliary-type carcinomas, 43.1% were classified as intestinal-type carcinomas, and 8.3% were classified as "unusual"-type carcinomas. Cytokeratin 20 was expressed in 28 (90.3%) of the 31 intestinal-type carcinomas, whereas it was always negative in the pancreaticobiliary histotype; CK7 was expressed in 32 (91.4%) of the 35 pancreaticobiliary-type carcinomas and in 18 (58.1%) of the 31 intestinal-type carcinomas. By univariate analysis, overall survival was influenced significantly by pathological T factor, lymph node involvement, and histological/immunohistochemical subtyping. Furthermore, using a multivariate Cox regression model, lymph node metastasis and CK20 were identified as significant independent factors related to prognosis.

CONCLUSION

Our results prove the clinical use of ampullary cancer subclassification based on different histotypes and indicate the useful role of the CK7/CK20 expression profile for consistent histopathological classification and prognostic relevance.

On the future contents of a small journal of histochemistry

In the last three years, more than 70,000 scientific articles have been published in peer reviewed journals on the application of histochemistry in the biomedical field: most of them did not appear in strictly histochemical journals, but in others dealing with cell and molecular biology, medicine or biotechnology. This proves that histochemistry is still an active and innovative discipline with relevance in basic and applied biological research, but also demonstrates that especially the small histochemical journals should likely reconsider their scopes and strategies to preserve their authorship. A review of the last three years volumes of the European Journal of Histochemistry, taken as an example of a long-time established small journal, confirmed that the published articles were widely heterogeneous in their topics and experimental models, as in this journal's tradition. This strongly suggests that a journal of histochemistry should keep its role as a forum open to an audience as broad as possible, publishing papers on cell and tissue biology in a wide variety of models. This will improve knowledge of the basic mechanisms of development and differentiation, while helping to increase the number of potential authors since scientists who generally do not use histochemistry in their research will find hints for the applications of histochemical techniques to novel still unexplored subjects.

Human equilibrative nucleoside transporter 1 expression predicts survival of advanced cholangiocarcinoma patients treated with gemcitabine-based adjuvant chemotherapy after surgical resection

OBJECTIVE

The aim of this study was to evaluate whether intratumoral human equilibrative nucleoside transporter 1 (hENT1) expression can predict the survival of advanced cholangiocarcinoma patients treated with adjuvant gemcitabine-based chemotherapy (AGC) after surgical resection.

BACKGROUND

There have been no reports concerning a useful predictive biomarker in patients with cholangiocarcinoma treated with adjuvant gemcitabine chemotherapy.

METHODS

Intratumoral hENT1 expression was investigated immunohistochemically in 105 patients with resected advanced cholangiocarcinoma. Relationships between intratumoral hENT1 expression and clinicopathological factors were evaluated by univariate and multivariate analyses. This study was a retrospective analysis on retrospectively collected tissue and data.

RESULTS

Fifty-one patients received AGC, and 54 did not. High and low intratumoral hENT1 expression was found in 74 (70%) and 31 patients (30%), respectively. There were no significant differences in clinicopathological factors between patients with high hENT1 expression and those with low hENT1 expression. Survival patients with high hENT1 expression were significantly better than those with low hENT1 expression among patients who received AGC (P = 0.008), but not among patients who did not (P = 0.894). Moreover, a significant difference in survival between patients who received AGC and those who did not was observed among patients with high hENT1 expression (P = 0.002), but not among patients with low hENT1 expression (P = 0.525). Intratumoral hENT1 expression was only an independent predictive factor for patients treated with AGC by multivariate analysis (P = 0.027).

CONCLUSIONS

Intratumoral hENT1 expression may be a potent predictive marker for advanced cholangiocarcinoma patients treated with AGC.

Identifying pathological biomarkers: histochemistry still ranks high in the omics era

In recent years, omic analyses have been proposed as possible approaches to diagnosis, in particular for tumours, as they should be able to provide quantitative tools to detect and measure abnormalities in gene and protein expression, through the evaluation of transcription and translation products in the abnormal vs normal tissues. Unfortunately, this approach proved to be much less powerful than expected, due to both intrinsic technical limits and the nature itself of the pathological tissues to be investigated, the heterogeneity deriving from polyclonality and tissue phenotype variability between patients being a major limiting factor in the search for unique omic biomarkers. Especially in the last few years, the application of refined techniques for investigating gene expression in situ has greatly increased the diagnostic/prognostic potential of histochemistry, while the progress in light microscopy technology and in the methods for imaging molecules in vivo have provided valuable tools for elucidating the molecular events and the basic mechanisms leading to a pathological condition. Histochemical techniques thus remain irreplaceable in pathologist's armamentarium, and it may be expected that even in the future histochemistry will keep a leading position among the methodological approaches for clinical pathology.

Histochemistry through the years, browsing a long-established journal: novelties in traditional subjects

Histochemical journals represent a traditional forum where methodological and technological improvements can be presented and validated in view of their applications to investigate not only cytology and histology in normal and diseased conditions but to test as well hypotheses on more basic issues for life sciences, such as comparative and evolutionary biology. The earliest scientific journals on histochemistry began their publication in the first half of the ‘50s of the last century, and their readership did not probably change over the years; rather, the authors’ interests may have progressively been changing as well as the main topics of their articles. This hypothesis is discussed, based on the subjects of the article published in the first and last ten years in the European Journal of Histochemistry, as an example of old journal which started publication in 1954, being since then the official organ of the Italian Society of Histochemistry. This survey confirmed that histochemistry has provided and still offers unique opportunities for studying the structure, chemical composition and function of cells and tissues in a wide variety of living organisms, especially when the topological distribution of specific molecular components has diagnostic or predictive significance, as it occurs in human and veterinary biology and pathology. Some subjects (e.g. histochemistry applied to muscle cells or to mineralized tissues) have recently become rather popular, whereas a wider application of the histochemical approach may be envisaged for plant cells and tissues.