Thymidylate Synthase expression as a predictor of clinical response to fluoropyrimidine-based chemotherapy in advanced colorectal cancer

Molecular Profile of Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is a relatively uncommon but highly aggressive primary liver cancer that originates within the liver. The aim of this study is to review the molecular profile of intrahepatic cholangiocarcinoma and its implications for prognostication and decision-making. This comprehensive characterization of ICC tumors sheds light on the disease's underlying biology and offers a foundation for more personalized treatment strategies. This is a narrative review of the prognostic and therapeutic role of the molecular profile of ICC. Knowing the molecular profile of tumors helps determine prognosis and support certain target therapies. The molecular panel in ICC helps to select patients for specific therapies, predict treatment responses, and monitor treatment responses. Precision medicine in ICC can promote improvement in prognosis and reduce unnecessary toxicity and might have a significant role in the management of ICC in the following years. The main mutations in ICC are in tumor protein p53 (TP53), Kirsten rat sarcoma virus (KRAS), isocitrate dehydrogenase 1 (IDH1), and AT-rich interactive domain-containing protein 1A (ARID1A). The rate of mutations varies significantly for each population. Targeting TP53 and KRAS is challenging due to the natural characteristics of these genes. Different stages of clinical studies have shown encouraging results with inhibitors of mutated IDH1 and target therapy for ARID1A downstream effectors. Fibroblast growth factor receptor 2 (FGFR2) fusions are an important target in patients with ICC. Immune checkpoint blockade can be applied to a small percentage of ICC patients. Molecular profiling in ICC represents a groundbreaking approach to understanding and managing this complex liver cancer. As our comprehension of ICC's molecular intricacies continues to expand, so does the potential for offering patients more precise and effective treatments. The integration of molecular profiling into clinical practice signifies the dawn of a new era in ICC care, emphasizing personalized medicine in the ongoing battle against this malignancy.

Folinic acid in colorectal cancer: esquire or fellow knight? Real-world results from a mono institutional, retrospective study

The stock of therapeutic weapons available in metastatic colorectal cancer (mCRC) has been progressively grown over the years, with improving both survival and patients' clinical outcome: notwithstanding advances in the knowledge of mCRC biology, as well as advances in treatment, fluoropyrimidine antimetabolite drugs have been for 30 years the mainstay of chemotherapy protocols for this malignancy. 5-Fluorouracil (5FU) seems to act differently depending on administration method: elastomer-mediated continuous infusion better inhibits Thymidylate Synthase (TS), an enzyme playing a pivotal role in DNA synthetic pathway. TS overexpression is an acknowledged poor prognosis predicting factor. The simultaneous combination of 5FU and folinate salt synergistically strengthens fluorouracil cytotoxic effect. In our experience, levofolinate and 5FU together in continuous infusion prolong progression free survival of patients suffering from mCRC, moreover decreasing death risk and showing a clear clinical benefit for patients, irrespective of RAS mutational status, primitive tumor side and metastases surgery.

SAHA Overcomes 5-FU Resistance in IFIT2-Depleted Oral Squamous Cell Carcinoma Cells

Simple Summary

IFIT2 depletion is associated with increased epithelial-mesenchymal transition and metastasis. The main aim of our study was to understand the link between drug resistance and IFIT2 depletion. In this study, we confirmed resistance to multiple common therapeutic drugs, particularly 5-FU, which showed especially high resistance in IFIT2-depleted cells. Interestingly, combination of SAHA and 5-FU overcame 5-FU resistance in IFIT2-depleted cells. Hence, our findings suggest that IFIT2 expression may be used as a biomarker to decide whether to undergo 5-FU treatment, but also the SAHA and 5-FU combination may be a potential new treatment regimen to augment 5-FU therapy in patients with thymidylate synthase-mediated drug-resistant oral squamous cell carcinoma.

Abstract

Interferon-induced protein with tetratricopeptide repeats 2 (IFIT2) is a member of the interferon-stimulated gene family that contains tetratricopeptide repeats (TPRs), which mediate protein–protein interactions in various biological systems. We previously showed the depletion of IFIT2 enhanced cell migration and metastatic activity in oral squamous cell carcinoma (OSCC) cells via the activation of atypical PKC signaling. In this study, we found that IFIT2-knockdown cells displayed higher resistance to 5-fluorouracil (5-FU) than control cells. The comet assay and annexin V analysis showed decreased DNA damage and cell death in IFIT2-knockdown cells compared to control cells treated with 5-FU. Cell cycle progression was also perturbed by 5-FU treatment, with the accumulation of IFIT2-depleted cells in S phase in a time-dependent manner. We further observed the overexpression of thymidylate synthase (TS) and thymidine kinase (TK) in IFIT2-knockdown cells. Inhibition of TS alone or double inhibition of TS and TK1 using the siRNA technique increased susceptibility to 5-FU in IFIT2-knockdown cells. We further identified that suberanilohydroxamic acid (SAHA) treatment decreased the expression of TS in IFIT2-knockdown cells and demonstrated that pretreatment with SAHA sensitized IFIT2-knockdown cells to 5-FU in vitro and in vivo. In conclusion, IFIT2 knockdown enhances TS expression, which mediates 5-FU resistance, and SAHA pretreatment suppresses TS expression and hence sensitizes cells to 5-FU. SAHA will be an effective strategy for the treatment of OSCC patients with 5-FU resistance.

Proteomics of Sentinel Lymph Nodes in Early Breast Cancer for Identification of Thymidylate Synthase as a Potential Biomarker to Flag Metastasis: A Preliminary Study

Introduction

Breast cancer is the second most common cancer in women across the world. Some of the patients who present in the early stage of disease are affected by metastasis to the axillary group of lymph nodes. The first among this group that is affected is called as sentinel lymph node, and its diagnosis is crucial for the staging of cancer thereby dictating the type of surgical therapy. Therefore, the sentinel lymph node status provides the most relevant information to the surgeon and patient prognosis. The expanded utilization of breast conservation surgery has declined the morbidity associated with mastectomy and axillary lymph node surgery. Recent interest is, therefore, centered on techniques that allow accurate assessment of the sentinel lymph node metastasis. A current procedure such as sentinel lymph node biopsy (SLNB) that is used to assess axillary lymph node metastasis is neither specific nor sensitive, and besides, it is time-consuming.

Objective

To compare the protein profiles between metastatic and non-metastatic lymph nodes to identify a biomarker that can flag lymph node metastasis.

Materials and Methods

Women with early breast cancer were screened using mammography imaging and recruited to the study. Surgical resection was done to remove the breast tissue, and sentinel lymph node was identified using fluorescein and methylene blue tracer. Lymph node was sliced, and one set was sent for histopathology, which was considered the gold standard to assess the metastatic status of the lymph node. One set of slices was taken for proteomic experiments. Proteins were labelled with fluorescent cyanine tags and were subjected to difference gel electrophoresis experiment. Differentially expressed spots that had at least a twofold relative ratio and consistent pattern across three sets of biological replicate experiments were marked. Gel spots were trypsin digested and identified on mass spectrometry machine. Validation study was done by Western blot experiment on the same set of samples.

Results

Thymidylate synthase has a twofold higher expression in the metastatic sentinel lymph nodes as compared to non-metastatic lymph nodes in early breast cancer patients.

Conclusion

Differential in gel expression proteomics is an ideal platform for the identification of potential protein biomarker candidates that can differentiate metastatic from non-metastatic lymph nodes in early breast cancer. The identification of thymidylate synthase offers a scope to develop an on-table diagnostic kit to assess the status of sentinel lymph nodes during mastectomy procedure to guide surgical management of axillary lymph nodes in early breast cancer.

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Pyrimidine Analogues as a New Class of Gram-Positive Antibiotics, Mainly Targeting Thymineless-Death Related Proteins

Multidrug-resistant (MDR) bacteria are widespread throughout the world and pose an increasingly serious threat to human and animal health. Besides implementing strict measures to prevent improper antibiotic use, it remains essential that novel antibiotics must be developed. These antibiotics need to exert their activity via mechanisms different from those employed by currently approved antibiotics. In this study, we used several 5-fluorouracil (5-FU) analogues as chemical probes and investigated the potential of these pyrimidine analogues as antibacterial agents. Several 5-FU derivatives exerted potent activity against strains of Gram-positive cocci (GPC) that are susceptible or resistant toward approved antibiotics, without showing cross-resistance. Furthermore, we have provided evidence that the pyrimidine analogues exerted anti-GPC activity via thymineless death by inhibition of thymidylate synthetase (ThyA) and/or inhibition of RNA synthesis. Interestingly, whole genome resequencing of in vitro-selected, pyrimidine analogue-resistant Staphylococcus aureus mutants indicated that S. aureus strains with pyrimidine-analogue resistance induced an amino acid (AA) substitution, deletion, and/or insertion into thymineless-death related proteins except for ThyA, or enhanced the ThyA transcription level. Thus, S. aureus may avoid altering the ThyA function by introducing an AA substitution, suggesting that the pyrimidine analogues, which directly bind to ThyA without phosphorylation, may be more effective and show a higher genetic barrier than the pyrimidines that depend on phosphorylation for activity. The findings of this study may assist in the future development of a novel class of antibiotics for combating MDR GPC, including methicillin-resistant S. aureus and vancomycin-resistant Enterococci.

Enhancing chemoradiation of colorectal cancer through targeted delivery of raltitrexed by hyaluronic acid coated nanoparticles

Combined modality therapy incorporating raltitrexed (RTX), a thymidylate synthase inhibitor, and radiation can lead to improved outcome for rectal cancer patients. To increase delivery and treatment efficacy, we formulated a hyaluronic acid (HA) coated nanoparticle encapsulating RTX (HARPs) through layer-by-layer assembly. These particles were determined to have a diameter of ∼115 nm, with a polydispersity index of 0.112 and a zeta potential of -22 mV. Cell uptake in CT26 cells determined through flow cytometry showed a ∼5-fold increase between untargeted and HA-coated particles. Through viability and DNA damage assays, we assessed the potency of the free RTX and HARPs, and found increased DNA damage in cells treated with the RTX-loaded nanoparticles administered concurrently with radiation. In vivo efficacy through tumor growth inhibition was investigated in a syngeneic murine colorectal cancer model. Nanoparticle treatment showed no acute toxicity in vivo, and all treatments showed survival benefits for their respective groups compared to controls. HARPs alone slowed tumor growth, although not significantly. Radiation alone and in combination with the HARPs showed significant growth delay. Notably, the combination treatment significantly hindered tumor progression relative to the HARPs highlighting the benefit of this multipronged treatment. These results provide a foundation for loading RTX in a nanoparticle formulation, and establish a combined radiation and drug dosing schedule to determine optimal tumor growth delay and subsequent treatment efficacy.

Effects of capecitabine treatment on the uptake of thymidine analogs using exploratory PET imaging agents: 18F-FAU, 18F-FMAU, and 18F-FLT

Background

A principal goal for the use of positron emission tomography (PET) in oncology is for real-time evaluation of tumor response to chemotherapy. Given that many contemporary anti-neoplastic agents function by impairing cellular proliferation, it is of interest to develop imaging modalities to monitor these pathways. Here we examined the effect of capecitabine on the uptake of thymidine analogs used with PET: 3’-deoxy-3’-[¹⁸F]fluorothymidine (¹⁸F-FLT), 1-(2’-deoxy-2’-[¹⁸F]fluoro-β-D-arabinofuranosyl) thymidine (¹⁸F-FMAU), and 1-(2’-deoxy-2’-[¹⁸F]fluoro-β-D-arabinofuranosyl) uracil (¹⁸F-FAU) in patients with advanced cancer.

Methods

Fifteen patients were imaged, five with each imaging agent. Patients had been previously diagnosed with breast, colorectal, gastric, and esophageal cancers and had not received therapy for at least 4 weeks prior to the first scan, and had not been treated with any prior fluoropyrimidines. Subjects were imaged within a week before the start of capecitabine and on the second day of treatment, after the third dose of capecitabine. Tracer uptake was quantified by mean standard uptake value (SUV_mean) and using kinetic analysis.

Results

Patients imaged with ¹⁸F-FLT showed variable changes in retention and two patients exhibited an increase in SUV_mean of 172.3 and 89.9 %, while the other patients had changes ranging from +19.4 to -25.4 %. The average change in ¹⁸F-FMAU retention was 0.2 % (range -24.4 to 23.1) and ¹⁸F-FAU was -10.2 % (range -40.3 to 19.2). Observed changes correlated strongly with SUV_max but not kinetic measurements.

Conclusions

This pilot study demonstrates that patients treated with capecitabine can produce a marked increase in ¹⁸F-FLT retention in some patients, which will require further study to determine if this flare is predictive of therapeutic response. ¹⁸F-FAU and ¹⁸F-FMAU showed little change, on average, after treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s40644-016-0092-2) contains supplementary material, which is available to authorized users.

Role of GSTM1 Copy Number Variant in the Prognosis of Thai Colorectal Cancer Patients Treated with 5-FU-based Chemotherapy

Background:

Glutathione S-transferase M1 (GSTM1) is involved in the detoxification of carcinogenic agents. DNA copy number variants of GSTM1 may be associated with cancer progression and may result in reduced survival time of various cancers. Determination of DNA copy number variants was here used to assess the association between GSTM1 copy number variant and pathological status and survival time of colorectal-cancer patients treated with 5-fluorouracil-based chemotherapy.

Methods:

One hundred thirteen Thai colorectal-cancer patients were investigated for GSTM1 copy number variant by real-time PCR. Relationships between gene copy number variants and clinico-pathological parameters were determined.

Result:

Associations were evident between GSTM1 copy number and stage of tumor (P = 0.026) and metastasis at diagnosis (P = 0.049), with odds ratio values of 0.2 and 0.3 respectively.

Conclusions:

GSTM1 copy number variant was here not related with reduced overall survival for the colorectal-cancer patients receiving 5-FU-based chemotherapy

Biomodulation of capecitabine by paclitaxel and carboplatin in advanced solid tumors and adenocarcinoma of unknown primary

Paclitaxel and carboplatin upregulate thymidine phosphorylase and thus may provide synergistic antitumor activity in combination with capecitabine (CTX). We, therefore, performed a phase I/II study of CTX. In the phase I study, patients with advanced solid tumors received carboplatin on day 1, paclitaxel on days 1, 8, 15 and capecitabine orally twice a day on days 8-21, every 4 weeks. Phase II patients with advanced adenocarcinoma of unknown primary (ACUP) were treated at the maximal tolerable dose. The phase I study enrolled 29 patients evaluable for dose limiting toxicity. The recommended phase II dose was capecitabine 750 mg/m(2) bid, paclitaxel 60 mg/m(2)/week and carboplatin AUC of 6. There were 9 confirmed responses, 5 partial responses and disease stabilization >3 months in 14 patients. The phase II study was prematurely terminated at 25 patients due to cessation of funding. The objective response rate was 32 % (95 % CI 0.15-0.54), the median progression-free survival 5.5 months (95 % CI 2.8-10.8 months) and the median overall survival 10.8 months (95 % CI 6.0-32.0 months). CTX demonstrated acceptable tolerability and antitumor activity. At the recommended dose level in patients with ACUP, this regimen showed encouraging preliminary activity.

ATM, THMS, and RRM1 protein expression in nasopharyngeal carcinomas treated with curative intent

BACKGROUND

In advanced nasopharyngeal carcinoma (NPC), biomarkers may help predict survival.

METHODS

Tumoral expression of ataxia-telangiectasia mutated (ATM), thymidylate synthetase (THMS), and ribonucleotide reductase subunit M1 (RRM1), was correlated with survival in patients with nonmetastatic NPC using quantitative fluorescence immunohistochemistry with automated quantitative digital image analysis.

RESULTS

Of the 146 patients included, 58 patients (40%) received concurrent chemoradiation therapy; the remainder was treated with radiation. Overall survival (OS) at 5 years was 71% (95% confidence interval [CI], 62% to 78%); disease-free survival (DFS) was 48% (95% CI, 39% to 57%). OS worsened for increasing values of ATM (hazard ratio [HR], 2.83; 95% CI, 1.01-7.94; p = .049) for values greater than the 75th percentile compared to less than the 25th percentile, but improved for tumors with higher THMS levels (HR, 0.44; 95% CI, 0.20-0.94; p = .033) for values greater than the 25th percentile compared to less than or equal to the 25th percentile. RRM1 was not associated with OS (p = .748). No biomarkers were associated with DFS.

CONCLUSION

In our cohort, relative overexpression of ATM and low THMS levels were associated with worse OS. © 2015 Wiley Periodicals, Inc. Head Neck 38: E384-E391, 2016.

Reversal of Multidrug Resistance by the Chinese Medicine Yiqi Jianpi Huaji Decoction and the Mechanism of Action in Human Gastric Cancer SGC7901/VCR Cells

Yiqi Jianpi Huaji Decoction (YJHD), a traditional Chinese medicinal formula composed of twelve ingredients, has recently been reported to have a good clinical curative effect. The purpose of the present study was to evaluate the effects of YJHD on SGC7901/VCR gastric cancer cells and to elucidate the possible mechanism of action. First, the effects of a low dose of YJHD in combination with chemotherapeutic agents on SGC7901/VCR cells were assessed using the CCK-8 assay and flow cytometry, and the effects of YJHD on genes and proteins involved in drug resistance (MDR1, MRP, TUBB3, STMN1, and TS) were evaluated. Furthermore, transfection of SGC7901/VCR cells with siRNAs targeting these genes inhibited their expression, and the efficacy of vincristine against the cells was dramatically improved in vitro when these genes were silenced. These results demonstrate that low-dose YJHD inhibited cell proliferation, induced apoptosis, reversed MDR, and increased sensitivity to chemotherapeutic agents in vitro by downregulating P-gp, MRP, TUBB3, and STMN1 expression. MDR can be reversed by siRNAs targeting genes involved in MDR, and this strategy for cancer treatment should be evaluated in future studies.

Cinnamaldehyde/chemotherapeutic agents interaction and drug-metabolizing genes in colorectal cancer

Cinnamaldehyde is an active monomer isolated from the stem bark of Cinnamomum cassia, a traditional oriental medicinal herb, which is known to possess marked antitumor effects in vitro and in vivo. The aim of the present study was to examine the potential advantages of using cinnamaldehyde in combination with chemotherapeutic agents commonly used in colorectal carcinoma (CRC) therapy, as well as to investigate the effect of cinnamaldehyde on chemotherapeutic-associated gene expression. The synergistic interaction of cinnamaldehyde and chemotherapeutic agents on human CRC HT-29 and LoVo cells was evaluated using the combination index (CI) method. The double staining with Annexin V conjugated to fluorescein-isothiocyanate and phosphatidylserine was employed for apoptosis detection. The expression of drug-metabolizing genes, including excision repair cross‑complementing 1 (ERCC1), orotate phosphoribosyltransferase (OPRT), thymidylate synthase (TS), breast cancer susceptibility gene 1 (BRCA1) and topoisomerase 1 (TOPO1), all in HT-29 and LoVo cells, with or without the addition of cinnamaldehyde, was examined by quantitative polymerase chain reaction (PCR). Cinnamaldehyde had a synergistic effect on the chemotherapeutic agents cytotoxicity in HT-29 and LoVo cells. In addition, cinnamaldehyde suppressed BRCA1, TOPO1, ERCC1 and TS mRNA expression, except for OPRT expression, which was markedly upregulated. Our findings indicate that cinnamaldehyde appears to be a promising candidate as an adjuvant in combination therapy with 5-fluorouracil (5-FU) and oxaliplatin (OXA), two chemotherapeutic agents used in CRC treatment. The possible mechanisms of its action may involve the regulation of drug‑metabolizing genes.

Low Mmp 9 and VEGF levels predict good oncologic outcome in mid and low rectal cancer patients with neoadjuvant chemoradiation

Background

The aim of this study was to evaluate apoptotic (Bcl-2, Bax expression, caspase-3 activity, and cytochrome-c) and angiogenic (MMP-9 levels and VEGF expression) markers in operable rectal cancer patients who were treated with preoperative chemoradiotherapy (CRT) followed by total mesorectal excision (TME). Understanding these factors will facilitate the identification of potential pathological responders before treatment, leading to better local control and survival rates.

Methods

Between March 2006 and March 2008, 29 patients withTNM Stage III (cT3 N+) mid or low rectal cancer were included in this study. Our sample consisted of 17 males (58.6%) and 12 females (41.4%). The median age was 60 years (range 24-88 years). Biopsy samples were taken from different portions of the tumors using flexible endoscopy before neoadjuvant CRT. Preoperatively, all patients received radiation (45-50.4 gray (Gy) in 25 cycles with concurrent 5-florouracil (5-FU) chemotherapy.

Results

A complete response was observed in 7 of 29 patients (24%). Bax staining was negative in 1 of the 7 patients (14%) in the pathological complete response (PCR) group and in 18 of the 22 patients (82%) in the no pathological complete response (noPCR) group (p = 0.001). MMP-9 and VEGF levels were higher in the noPCR group than the PCR group (p = 0.04, p = 0.05 respectively). No statistically significant differences were found between VEGF and MMP-9 levels in nodal downstaging. No statistically significant relationships were found between the other apoptotic factors (Bcl 2, cytochrome-c, and caspase-3 activity) and pathological response rate (p > 0.05).

Conclusion

In neoadjuvant CRT patients, high levels of Bax expression and low levels of VEGF and MMP-9 expression on preoperative biopsies indicate that the patient will potentially be a good pathological responder.

Predictive markers of capecitabine sensitivity identified from the expression profile of pyrimidine nucleoside-metabolizing enzymes

Molecular markers predicting sensitivity to anticancer drugs are important and useful not only for selecting potential responders but also for developing new combinations. In the present study, we analyzed the difference in the sensitivity of xenograft models to capecitabine (Xeloda®), 5'-deoxy-5-fluorouridine (5'-DFUR, doxifluridine, Furtulon®) and 5-FU by comparing the mRNA levels of 12 pyrimidine nucleoside-metabolizing enzymes. Amounts of mRNA in the tumor tissues of 80 xenograft models were determined by real-time RT-PCR and mutual correlations were examined. A clustering analysis revealed that the 12 enzymes were divided into two groups; one group consisted of 8 enzymes, including orotate phosphoribosyl transferase (OPRT), TMP kinase (TMPK) and UMP kinase (UMPK), and was related to the de novo synthesis pathway for nucleotides, with mRNA expression levels showing significant mutual correlation. In the other group, 4 enzymes, including thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD), were involved in the salvage/degradation pathway of the nucleotides, and the mRNA levels of this group were dispersed more widely than that of the de novo group. Antitumor activity was assessed in 24 xenograft models for each drug. The antitumor activity of capecitabine and 5'-DFUR correlated significantly with the mRNA levels of TP and with the TP/DPD ratio, whereas the activity of 5-FU correlated significantly with OPRT, TMPK, UMPK and CD. In a stepwise regression analysis, TP and DPD were found to be independent predictive factors of sensitivity to capecitabine and 5'-DFUR, and UMPK was predictive of sensitivity to 5-FU. These results indicate that the predictive factors for sensitivity to capecitabine and 5'-DFUR in xenograft models may be different from those for 5-FU, suggesting that these drugs may have different responders in clinical usage.

The effects of 5-fluoruracil treatment on 3'-fluoro-3'-deoxythymidine (FLT) transport and metabolism in proliferating and non-proliferating cultures of human tumor cells

3'-Fluoro-3'-deoxythymidine (FLT) positron emission tomography (PET) has been proposed for imaging thymidylate synthase (TS) inhibition. Agents that target TS and shut down de novo synthesis of thymidine monophosphate increase the uptake and retention of FLT in vitro and in vivo because of a compensating increase in the salvage pathway. Increases in both thymidine kinase-1 (TK1) and the equilibrative nucleoside transporter hENT1 have been reported to underlie this effect. We examined whether the effects of one TS inhibitor, 5-fluorouracil (5FU), on FLT uptake require proliferating cells and whether the effects are limited to increasing TK1 activity.

METHODS

The effects of 5FU on FLT transport and metabolism, TK1 activity, and cell cycle progression were evaluated in the human tumor cell line, A549, maintained as either a proliferating or non-proliferating culture.

RESULTS

There were dose-dependent increases in FLT uptake that peaked after a 10 μM 5FU exposure and then declined to baseline levels or below at higher doses in both proliferating and non-proliferating cultures. The dose-dependence for FLT uptake was mirrored by changes in TK1 activity. S phase fraction did not correlate with FLT uptake in proliferating cultures. Chemical inhibition of hENT1 reduced overall levels of FLT uptake but did not affect the low dose increase in FLT uptake.

CONCLUSIONS

5FU only affects FLT uptake in proliferating A549 cells and increases in FLT uptake are directly related to increased TK1 activity. Our studies did not support a role for hENT1 in the increased uptake of FLT after exposure to 5FU. Our studies with A549 cells support the suggestion that FLT-PET could provide a measure of TS inhibition in vivo.

Inhibition of dUTPase induces synthetic lethality with thymidylate synthase-targeted therapies in non-small cell lung cancer

Chemotherapies that target thymidylate synthase (TS) continue to see considerable clinical expansion in non-small cell lung cancer (NSCLC). One drawback to TS-targeted therapies is drug resistance and subsequent treatment failure. Novel therapeutic and biomarker-driven strategies are urgently needed. The enzyme deoxyuridine triphosphate nucleotidohydrolase (dUTPase) is reported to protect tumor cells from aberrant misincorporation of uracil during TS inhibition. The goal of this study was to investigate the expression and significance of dUTPase in mediating response to TS-targeted agents in NSCLC. The expression of dUTPase in NSCLC cell lines and clinical specimens was measured by quantitative real-time reverse transcriptase PCR and immunohistochemistry. Using a validated RNA interference approach, dUTPase was effectively silenced in a panel of NSCLC cell lines and response to the fluoropyrimidine fluorodeoxyuridine (FUdR) and the antifolate pemetrexed was analyzed using growth inhibition and clonogenic assays. Apoptosis was analyzed by flow cytometry. Significant variation in the quantity and cellular expression of dUTPase was observed, including clear evidence of overexpression in NSCLC cell line models and tumor specimens at the mRNA and protein level. RNA interference-mediated silencing of dUTPase significantly sensitized NSCLC cells to growth inhibition induced by FUdR and pemetrexed. This sensitization was accompanied by a significant expansion of intracellular dUTP pools and significant decreases in NSCLC cell viability evaluated by clonogenicity and apoptotic analyses. Together, these results strongly suggest that uracil misincorporation is a potent determinant of cytotoxicity to TS inhibition in NSCLC and that inhibition of dUTPase is a mechanism-based therapeutic approach to significantly enhance the efficacy of TS-targeted chemotherapeutic agents.

What can the molecular pathologist offer for optimal decision making?

As a consequence of new innovative therapies and therapeutic combinations, the treatment of advanced colorectal cancer is becoming increasingly complex. Validated molecular biomarkers could contribute to patient management, but until recently, none has been routinely used. With the recognition that activating mutations of the KRAS oncogene can predict resistance to anti-epidermal growth factor receptor agents, the clinical value of biomarkers in advanced colorectal cancer has been brought to the fore. Prognostic and predictive biomarkers that reflect the molecular and therapeutic complexities of advanced colorectal cancer may provide valuable information regarding likely clinical outcome and therapeutic response and thus may improve patient management and therapeutic agent selection. Such biomarkers are discussed herein.

Thymidylate synthase expression as a predictor of clinical response to 5-fluorouracil-based chemoradiotherapy in patients with maxillary sinus squamous cell carcinoma

OBJECTIVE

The aim of this study was to evaluate the immunohistochemical TS expression in patients with maxillary sinus SCC.

METHODS

The value of immunohistochemical TS expression as a predictive indicator for 5-FU efficacy was retrospectively examined in 47 patients with maxillary sinus SCC.

RESULTS

Of the 47 patients, 29 (62%) showed complete response for 5-FU based chemoradiotherapy. Seventeen of 19 (89%) TS low cases showed a complete response, whereas 12 of 28 (43%) TS high cases showed complete response for 5-FU based chemoradiotherapy. Low TS patients had significantly better response rates compared with high TS patients.

CONCLUSION

These findings suggest that TS expression affects the chemotherapeutic effect of 5-FU in patients with maxillary sinus SCC and the assessment of TS expression level might be useful both in the management and in the treatment of maxillary sinus SCC.

Aprataxin tumor levels predict response of colorectal cancer patients to irinotecan-based treatment

PURPOSE

Irinotecan (CPT11) treatment significantly improves the survival of colorectal cancer patients and is routinely used for the treatment of these patients, alone or in combination with other agents. However, only 20% to 30% of patients show an objective response to irinotecan, and there is great need for new molecular markers capable of identifying the subset of patients who are unlikely to respond.

EXPERIMENTAL DESIGN

Here we used microarray analysis of a panel of 30 colorectal cancer cell lines and immunohistochemistry to identify and validate a new biomarker of response to irinotecan.

RESULTS

A good correlation was observed between irinotecan sensitivity and the expression of aprataxin (APTX), a histidine triad domain superfamily protein involved in DNA repair. Moreover, using an isogenic in vitro system deficient in APTX, we show that aprataxin directly regulates the cellular sensitivity to camptothecin, suggesting that it could be used to predict patient response to irinotecan. We constructed a tissue microarray containing duplicate tumor samples from 135 patients that received irinotecan for the treatment of advanced colorectal cancer. Immunohistochemical assessment of the tumor levels of aprataxin showed a significant association with treatment response and patient survival. Patients with low aprataxin had longer progression-free (9.2 versus 5.5 months; P = 0.03) and overall survival (36.7 versus 19.0 months; P = 0.008) than patients with high tumor aprataxin. No associations were found between coding APTX variants and aprataxin levels or camptothecin sensitivity.

CONCLUSIONS

These results show that aprataxin tumor levels can be used to identify patients with low probability of response to irinotecan-based therapy who are ideal candidates to receive treatment with alternative agents in an attempt to improve patient survival.

Trifluorothymidine resistance is associated with decreased thymidine kinase and equilibrative nucleoside transporter expression or increased secretory phospholipase A2

Trifluorothymidine (TFT) is part of the novel oral formulation TAS-102, which is currently evaluated in phase II studies. Drug resistance is an important limitation of cancer therapy. The aim of the present study was to induce resistance to TFT in H630 colon cancer cells using two different schedules and to analyze the resistance mechanism. Cells were exposed either continuously or intermittently to TFT, resulting in H630-cTFT and H630-4TFT, respectively. Cells were analyzed for cross-resistance, cell cycle, protein expression, and activity of thymidine phosphorylase (TP), thymidine kinase (TK), thymidylate synthase (TS), equilibrative nucleoside transporter (hENT), gene expression (microarray), and genomic alterations. Both cell lines were cross-resistant to 2'-deoxy-5-fluorouridine (>170-fold). Exposure to IC(75)-TFT increased the S/G(2)-M phase of H630 cells, whereas in the resistant variants, no change was observed. The two main target enzymes TS and TP remained unchanged in both TFT-resistant variants. In H630-4TFT cells, TK protein expression and activity were decreased, resulting in less activated TFT and was most likely the mechanism of TFT resistance. In H630-cTFT cells, hENT mRNA expression was decreased 2- to 3-fold, resulting in a 5- to 10-fold decreased TFT-nucleotide accumulation. Surprisingly, microarray-mRNA analysis revealed a strong increase of secretory phospholipase-A2 (sPLA2; 47-fold), which was also found by reverse transcription-PCR (RT-PCR; 211-fold). sPLA2 inhibition reversed TFT resistance partially. H630-cTFT had many chromosomal aberrations, but the exact role of sPLA2 in TFT resistance remains unclear. Altogether, resistance induction to TFT can lead to different mechanisms of resistance, including decreased TK protein expression and enzyme activity, decreased hENT expression, as well as (phospho)lipid metabolism. Mol Cancer Ther; 9(4); 1047-57. (c)2010 AACR.

Comparative analysis of thymidylate synthase at the protein, mRNA, and DNA levels as prognostic markers in colorectal adenocarcinoma

BACKGROUND AND OBJECTIVES

To determine the best routinely available molecular methodology for assessing thymidylate synthase (TS) as a prognostic marker in colorectal adenocarcinoma, TS was examined at the protein, mRNA, and DNA levels. Direct comparison of these routinely available assays has not been systematically studied across a large colon cancer patient cohort with long-term follow-up.

METHODS

We studied 150 surgically resected colorectal adenocarcinoma patients who received postoperative 5-Fluorouracil (5-FU) chemotherapy. TS immuunohistochemistry and real-time quantitative RT-PCR and PCR genotyping on patient-matched tumor and normal tissues were performed.

RESULTS

Surprisingly, mRNA values in normal tissue varied from 0.11 to 62.0 and significantly correlated with mRNA values of matched tumor tissues. Although higher tumor/normal ratios of mRNA expression trended toward poorer patient survival, neither this nor TS immunohistochemistry results were statistically significant predictors. TS tumor genotype was generally concordant with matched normal tissues. Further, the 2R/3R genotype of 5'-TSER was significantly correlated with poorer patient survival (P = 0.0249) and was also an independent prognostic marker on multivariate analysis.

CONCLUSION

TS genotyping on paraffin-embedded fixed tissues proved to be the most useful method for prediction of outcome of 5-FU treatment in patients with colorectal adenocarcinoma.

Apocrine metaplasia of breast cancer: clinicopathological features and predicting response

BACKGROUND

Tailor-made therapies are currently gaining prominence, and the clarification of predictive markers for anticancer agents represents an important research issue. From our institutional neoadjuvant experience, apocrine carcinoma showed a high correlation with therapeutic effect against breast cancer. We thus considered that apocrine metaplasia (AM) might represent a predictive marker for breast cancer.

METHODS

A total of 210 primary invasive breast cancers from Japanese patients were scored according to the size of cytoplasmic granules and abundance of cytoplasm, then classified into three categories: non-AM, incomplete AM and complete AM. Clinicopathological features were evaluated based on these classifications.

RESULTS

Distribution according to the classification of AM was: non-AM, 61%; incomplete AM, 36%; and complete AM, 3%. No significant differences with regard to estrogen receptor, progesterone receptor, human epidermal growth factor receptor type 2, androgen receptor or bcl-2 were observed among the three groups. Gross cystic fluid protein-15 showed a high positive rate (83%) for complete AM. Cases of incomplete AM and complete AM were combined to form the AM group. Among lymph node-positive patients without chemotherapy, the 10-year recurrence-free survival (RFS) rate was 85% for non-AM and 44% for AM (p < 0.05). Conversely, among the lymph node-positive group with chemotherapy, the 10-year RFS rate was 45% for non-AM and 75% for AM (p < 0.05). Prognoses for non-AM and AM were turned around by chemotherapy. Lymph node metastasis was related to prognosis in multivariate analysis, although AM did not remain an independent prognosticator.

CONCLUSIONS

Apocrine metaplasia appears to offer an effective predictive marker for anticancer therapy.

Successful treatment of advanced gallbladder cancer with an anticancer drug S-1: assessment based on intratumoral gene

While surgical resection is the most effective treatment for gallbladder cancer, most of these cancers are not resectable at the time of diagnosis, and therefore, chemotherapy serves as the primary therapy in many cases. However, to date, there is no standard chemotherapy for this cancer. We report a case of advanced gallbladder cancer for which the anticancer drug S-1 was effective. The patient was a 53-year-old woman who presented with a huge ovarian tumor. On workup, all abdominal images revealed the presence of advanced gallbladder cancer that had invaded the liver. Because the gallbladder formed a relatively hard and swollen mass involving the omentum, as revealed during exploration, the surgical resection of the gallbladder was not possible at that time, and only hysterectomy and bilateral salpingo-oophorectomy were performed. She started on the anticancer drug S-1 just after this operation. S-1 is a prodrug of 5-fluorouracil (5-FU), and contains 5-chloro-2-4-dihydroxypyridine (CDHP), an inhibitor of dihydropyrimidine dehydrogenase (DPD) that rapidly degrades 5-FU. Eight months after the first operation, radical cholecystectomy was performed. Pathologically, the tumor was diagnosed as an adenocarcinoma of the gallbladder, and no evidence of liver invasion was found. Intratumoral gene expression analysis of the resected gallbladder revealed significantly elevated DPD expression. We suggest that the rapid degradation of 5-FU mediated by this high DPD in our patient was significantly blocked by the CDHP in S-1, and that the efficacy of 5-FU was consequently maintained at the maximum level.

Pharmacogenetic analyses of hematotoxicity in advanced gastric cancer patients receiving biweekly fluorouracil, leucovorin, oxaliplatin and docetaxel (FLOT): a translational study of the Arbeitsgemeinschaft Internistische Onkologie (AIO)

BACKGROUND

Docetaxel-based chemotherapy regimens have demonstrated activity in advanced gastric cancer (AGC). However, a high rate of grade 3/4 hematotoxicity was reported with these regimens. Our purpose was to identify pharmacogenetic markers with potential to detect patients with increased risk to encounter severe hematotoxicity following treatment with 5-fluorouracil, leucovorin, oxaliplatin and docetaxel (FLOT).

PATIENTS AND METHODS

Polymorphisms of genes involved in DNA repair, drug transport and metabolism were determined in 50 AGC patients receiving FLOT within a phase II trial. DNA was extracted from peripheral blood. Genotyping was carried out using PCR-based techniques.

RESULTS

Patients possessing TS-group A genotypes (2R/2R, 2R/3RC, 3RC/3RC) were at increased risk for grade 3/4 hematotoxicity compared with patients harboring a TS-group B genotype (2R/3RG, 3RC/3RG, 3RG/3RG). In all, 59% (20 of 34) of patients with TS-group A genotypes developed grade 3/4 hematotoxicity compared with 25% (4 of 16) of those having TS-group B genotypes (P=0.035). Grade 3/4 neutropenia occurred in 53% (18 of 34) of TS-group A patients compared with 19% (3 of 16) in TS-group B patients (P=0.032). Multivariate analyses identified TS-group A genotypes as significant predictors of grade 3/4 overall hematotoxicity {odds ratio (OR) 4.62 [95% confidence interval (CI) 1.22; 17.44], P=0.024} and neutropenia [OR 5.74 (95% CI 1.03; 32.08), P=0.047].

CONCLUSION

TS-promoter polymorphisms may be associated with hematotoxicity in AGC patients receiving FLOT.

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Use of Tumor Markers in Testicular, Prostate, Colorectal, Breast, and Ovarian Cancers

Background: Updated National Academy of Clinical Biochemistry (NACB) Laboratory Medicine Practice Guidelines for the use of tumor markers in the clinic have been developed.

Methods: Published reports relevant to use of tumor markers for 5 cancer sites—testicular, prostate, colorectal, breast, and ovarian—were critically reviewed.

Results: For testicular cancer, α-fetoprotein, human chorionic gonadotropin, and lactate dehydrogenase are recommended for diagnosis/case finding, staging, prognosis determination, recurrence detection, and therapy monitoring. α-Fetoprotein is also recommended for differential diagnosis of nonseminomatous and seminomatous germ cell tumors. Prostate-specific antigen (PSA) is not recommended for prostate cancer screening, but may be used for detecting disease recurrence and monitoring therapy. Free PSA measurement data are useful for distinguishing malignant from benign prostatic disease when total PSA is &lt;10 μg/L. In colorectal cancer, carcinoembryonic antigen is recommended (with some caveats) for prognosis determination, postoperative surveillance, and therapy monitoring in advanced disease. Fecal occult blood testing may be used for screening asymptomatic adults 50 years or older. For breast cancer, estrogen and progesterone receptors are mandatory for predicting response to hormone therapy, human epidermal growth factor receptor-2 measurement is mandatory for predicting response to trastuzumab, and urokinase plasminogen activator/plasminogen activator inhibitor 1 may be used for determining prognosis in lymph node–negative patients. CA15-3/BR27–29 or carcinoembryonic antigen may be used for therapy monitoring in advanced disease. CA125 is recommended (with transvaginal ultrasound) for early detection of ovarian cancer in women at high risk for this disease. CA125 is also recommended for differential diagnosis of suspicious pelvic masses in postmenopausal women, as well as for detection of recurrence, monitoring of therapy, and determination of prognosis in women with ovarian cancer.

Conclusions: Implementation of these recommendations should encourage optimal use of tumor markers.

The role of DNA synthesis imaging in cancer in the era of targeted therapeutics

Non-specific targets such as DNA and microtubules have been the mainstay of cancer therapeutics and the most effective clinical agents until a decade ago. Advances in genetics, molecular and cellular biology over the past decade led to the development of a new generation of agents that are far more specific and effective. In contrast to progress seen with therapeutic agents, general monitoring targets such as proliferation imaging are just gaining momentum and targeted imaging is still in its infancy. In these paradoxical times, this review assesses the role of proliferation imaging in monitoring the efficacy of targeted therapeutics.

AQUA analysis of thymidylate synthase reveals localization to be a key prognostic biomarker in 2 large cohorts of colorectal carcinoma

CONTEXT

Increased thymidylate synthase expression is a marker for decreased survival in colorectal cancer.

OBJECTIVE

Thymidylate synthase localizes to both the nucleus and cytoplasm, but how the relationship of these expression levels affects colon cancer outcome has yet to be determined.

DESIGN

Using AQUA, we assessed prognosis of thymidylate synthase expression as a function of subcellular localization in 2 retrospective cohorts of colorectal carcinoma. We used the first cohort (n = 599) as a training set, subsequently validating optimal expression cut points in the second cohort (n = 447).

RESULTS

A significant association between decreased 5-year disease-specific survival and increased nuclear expression (16% decreased survival [72% to 56%] for the top 60% of nuclear-expressing tumors [P < .001]) and cytoplasmic expression (12% decreased survival [70% to 58%] for the top 54% of cytoplasmic-expressing tumors [P = .02]) was observed for the training set. A higher nuclear to cytoplasmic ratio also correlated significantly with decreased survival (15% decreased survival [66% to 51%] for the top 25% of tumors [P < .001]). Applying these findings to the validation set, as a function of time to recurrence, only the ratio (P = .03 [expression ratio]; P = .18 [nuclear]; P = .71 [cytoplasmic]) showed a significant association with decreased time to recurrence. Additionally, the expression ratio significantly added to the prognostic value given by the primary tumor pathologic classification and nodal status.

CONCLUSIONS

These data suggest the relationship of nuclear to cytoplasmic thymidylate synthase expression, given as a ratio of continuous AQUA scores, to be a strong predictor of colon cancer survival.

ERCC2 2251A>C genetic polymorphism was highly correlated with early relapse in high-risk stage II and stage III colorectal cancer patients: a preliminary study

BACKGROUND

Early relapse in colorectal cancer (CRC) patients is attributed mainly to the higher malignant entity (such as an unfavorable genotype, deeper tumor invasion, lymph node metastasis and advance cancer stage) and poor response to chemotherapy. Several investigations have demonstrated that genetic polymorphisms in drug-targeted genes, metabolizing enzymes, and DNA-repairing enzymes are all strongly correlated with inter-individual differences in the efficacy and toxicity of many treatment regimens. This preliminary study attempts to identify the correlation between genetic polymorphisms and clinicopathological features of CRC, and evaluates the relationship between genetic polymorphisms and chemotherapeutic susceptibility of Taiwanese CRC patients. To our knowledge, this study discusses, for the first time, early cancer relapse and its indication by multiple genes.

METHODS

Six gene polymorphisms functional in drug-metabolism - GSTP1 Ile105Val, ABCB1 Ile1145Ile, MTHFR Ala222Val, TYMS double (2R) or triple (3R) tandem repeat - and DNA-repair genes - ERCC2 Lys751Gln and XRCC1 Arg399Gln - were assessed in 201 CRC patients using a polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) technique and DNA sequencing. Patients were diagnosed as either high-risk stage II (T2 and 3 N0 M0) or III (any T N1 and 2 M0) and were administered adjuvant chemotherapy regimens that included 5-fluorouracil (5FU) and leucovorin (LV). The correlations between genetic polymorphisms and patient clinicopathological features and relapses were investigated.

RESULTS

In this study, the distributions of GSTP1 (P = 0.003), ABCB1 (P = 0.001), TYMS (P < 0.0001), ERCC2 (P < 0.0001) and XRCC1 (P = 0.006) genotypes in the Asian population, with the exception of MTHFR (P = 0.081), differed significantly from their distributions in a Caucasian population. However, the unfavorable genotype ERCC2 2251A>C (P = 0.006), tumor invasion depth (P = 0.025), lymph node metastasis (P = 0.011) and cancer stage (P = 0.008) were significantly correlated with early relapse. Patients carrying the ERCC2 2251AC or2251CC genotypes had a significantly increased risk of early relapse (OR = 3.294, 95% CI, 1.272-8.532).

CONCLUSION

We suggest that ERCC2 2251A>C alleles may be genetic predictors of early CRC relapse.

Measurement of DPD and TS transcripts aimed to predict clinical benefit from fluoropyrimidines: confirmation of the trend in Russian colorectal cancer series and caution regarding the gene referees

BACKGROUND

Measurement of intratumoral expression of dihydropyrimidine dehydrogenase (DPD) and thymidylate synthase (TS) may have some value in predicting the response to fluoropyrimidine-containing therapy.

PATIENTS AND METHODS

We attempted to validate this association in a series of Russian metastatic colorectal cancer cases. While replicating already published protocols, we unexpectedly found that the use of commonly utilized gene referees, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and beta-actin, may lead to artifacts due to pseudogene-driven amplification from the genomic DNA template. We have developed a real-time PCR protocol which amplifies short PCR fragments, thus allowing efficient analysis of archival formalin-fixed paraffin-embedded tumor samples, and relies on succinate dehydrogenase (SDHA) as a gene referee, therefore avoiding amplification from genomic DNA.

RESULTS

Low content of DPD transcripts was observed in 13/20 (65%) patients with disease control (tumor response or disease stabilization) as compared to only 3/9 (33%) subjects with progressive disease (p = 0.11). Despite the low number of patients, this association reached the level of statistical significance when similar analysis was done for TS expression (11/20 (55%) vs. 1/9 (11%); p = 0.03).

CONCLUSIONS

Our data confirm that low DPD and TS expressors have higher chances of success of fluoropyrimidine-containing regimens.

Synergistic interaction between tetrandrine and chemotherapeutic agents and influence of tetrandrine on chemotherapeutic agent-associated genes in human gastric cancer cell lines

PURPOSE

Tetrandrine (Tet), a bis-benzylisoquinoline alkaloid that was isolated from the dried root of Hang-Fang-Chi (Stephania tetrandra S. Moore), is well known as processing a marked antitumor effect in vitro and in vivo. The aim of this study was to assess the interaction between tetrandrine and chemotherapeutic agents widely used in gastric cancer treatment, and to investigate the influence of tetrandrine on chemotherapeutic agent-associated gene expression and apoptosis.

METHODS

Synergistic interaction on human gastric cancer BGC-823 and MKN-28 cells was evaluated using the combination index (CI) method. The double staining with both Annexin-V-FITC and PI was employed to distinguish the apoptotic cells from living cells. Expression of chemotherapeutic agent-associated genes, i.e., excision repair cross-complementing 1 (ERCC1), thymidylate synthase (TS), class III beta-tubulin (beta-tubulin III) and tau, of BGC-823 cells with or without tetrandrine treatment were measured by real-time quantitative PCR.

RESULTS

Tetrandrine had a synergistic effect on the cytotoxicity of chemotherapeutic agents in both two gastric cancer cell lines. The combination of tetrandrine and chemotherapeutic agents could also induce apoptosis in a synergistic manner. Tetrandrine could suppress the mRNA expression of ERCC1, TS, beta-tubulin III and tau. Most prominently, ERCC1, TS and beta-tubulin III mRNA levels were markedly suppressed at 0.29-, 0.12- and 0.60-fold, respectively, by the presentation of tetrandrine.

CONCLUSION

Tetrandrine appears a promising candidate for combining with three chemotherapeutic agents. The possible mechanisms might be the synergistic apoptotic effect and the downregulation of chemotherapeutic agent-associated genes.

Prediction of clinical outcome of fluoropyrimidine-based chemotherapy for gastric cancer patients, in terms of the 5-fluorouracil metabolic pathway

Fluoropyrimidines are widely used in chemotherapy regimens for metastatic gastric cancer. Interindividual variation in the enzyme activity of the 5-fluorouracil (FU) metabolic pathway can affect the extent of 5-FU metabolism and affect the efficacy of 5-FU based chemotherapy. In this review, the role of the genetic factors affecting the therapeutic efficacy of fluoropyrimidines is discussed, with a special emphasis on enzymes involved in the 5-FU metabolic pathway. The gene expressions of thymidylate synthase, dihydropyrimidine dehydrogenase, thymidine phosphorylase, and orotate phosphoribosyltransferase are discussed in relation to the efficacy of fluoropyrimidine treatment for metastatic gastric cancer. These candidate genes, along with others yet to be identified, could allow accurate prediction of the clinical outcome in patients receiving fluoropyrimidine-based chemotherapy in the future. Well-designed and large prospective studies, which include relevant pharmacogenetic parameters, are needed to confirm the values required to predict clinical outcome.

Molecular-based choice of cancer therapy: realities and expectations

Current choice of cancer therapy is usually empirical and relies mainly on the statistical prediction of the treatment success. Molecular research provides some opportunities to personalize antitumor treatment. For example, life-threatening toxic reactions can be avoided by the identification of subjects, who carry susceptible genotypes of drug-metabolizing genes (e.g. TPMT, UGT1A1, MTHFR, DPYD). Tumor sensitivity can be predicted by molecular portraying of targets and other molecules associated with drug response. Tailoring of antiestrogen and trastuzumab therapy based on hormone and HER2 receptor status has already become a classical example of customized medicine. Other predictive markers have been identified both for cytotoxic and for targeted therapies, and include, for example, expression of TS, TP, DPD, OPRT, ERCC1, MGMT, TOP2A, class III beta-tubulin molecules as well as genomic alterations of EGFR, KIT, ABL oncogenes.

Thymidylate synthase expression in resectable and unresectable pancreatic cancer: role as predictive or prognostic marker?

BACKGROUND AND AIMS

Thymidylate synthase (TS) is an important enzyme for DNA synthesis and the target for 5-fluorouracil (5-FU). Its expression may determine the outcome of patients with gastrointestinal cancers. We examined the prognostic and predictive value of TS-protein expression in patients with ductal adenocarcinoma of the pancreas.

METHODS

TS expression from 131 patients with ductal adenocarcinoma of the pancreas was analyzed by immunohistochemistry in paraffin-embedded primary tumour specimens or biopsies.

RESULTS

The median disease-specific survival among all patients (n=131) was 13 months. The invasion depth, the presence of metastases, grading and Union Internationale Contre le Cancer [International Union Against Cancer] (UICC) stage were associated with survival. Among resected patients (n=98), a difference in median survival was seen in the group receiving postoperative adjuvant treatment (21.1 months) compared with the group treated by surgery alone (12.4 months) (p=0.025). Low- and high-TS immunoreactivity was present in 74 (56%) and 56 (43%) of the cancers, respectively. One sample was not evaluable. No difference in median survival was observed among low- and high-TS-expressing tumours. Among patients undergoing resection and receiving postoperative intra-arterial chemotherapy (n=23), a marked trend to a longer median survival was seen for the group with low-TS-expressing tumours compared with the corresponding high-TS group (25.0 vs 16.0 months) (p=0.3834). There was no difference in survival among all palliative treated patients with low- and high-TS-expressing tumours.

CONCLUSION

Especially patients undergoing tumour resection with low-TS values seemed to have taken advantage from an intensified postoperative chemotherapeutic protocol. However due to the heterogeneous group of patients in the present report, larger trials of more homogenous patient populations will be necessary to confirm this hypothesis.

The impact of surgically induced ischaemia on protein levels in patients undergoing rectal cancer surgery

The goal of targeted therapy has driven a search for markers of prognosis and response to adjuvant therapy. The surgical resection of a solid tumour induces tissue ischaemia and acidosis, both potent mediators of gene expression. This study investigated the impact of colorectal cancer (CRC) surgery on prognostic and predictive marker levels. Tumour expression of thymidylate synthase, thymidine phosphorylase, cyclin A, vascular endothelial growth factor (VEGF), carbonic anhydrase-9, hypoxia inducible factor-1α, and glucose transporter-1 (GLUT-1) proteins was determined before and after rectal cancer surgery. Spectral imaging of tissue sections stained by immunohistochemistry provided quantitative data. Surgery altered thymidylate synthase protein expression (P=0.02), and this correlated with the change in the proliferation marker cyclin A. The expression of hypoxia inducible factor-1α, VEGF, and GLUT-1 proteins was also different following surgery. Colorectal cancer surgery significantly impacts on intratumoral gene expression, suggesting archival specimens may not accurately reflect in situ marker levels. Although rectal cancer was the studied model, the results may be applicable to any solid tumour undergoing extirpation in which molecular markers have been proposed to guide patient therapy.

A haplotype of the methylenetetrahydrofolate reductase gene predicts poor tumor response in rectal cancer patients receiving preoperative chemoradiation

OBJECTIVE

The objective of the present study was to evaluate whether germline methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms as well as polymorphisms in the thymidylate synthase gene promoter, namely the variable number tandem repeat polymorphism (TS VNTR) and the intrarepeat G to C single nucleotide polymorphism (TS SNP), are predictive markers of tumor regression in rectal cancer patients following preoperative chemoradiotherapy.

BASIC METHODS

Blood samples from 125 patients with primary adenocarcinoma of the mid-low rectum who received 5-fluorouracil-based chemotherapy and external beam radiotherapy (median dose 48.4 Gy), 125 patients (women n=45, men n=80; median age 60 years, range 31-79 years) were genotyped. Response to preoperative treatment was evaluated employing the Tumor Regression Grade criteria. On the basis of the pathologic response, patients were classified as responders (TRG 1-2, n=48) and non-responders (TRG 3-5, n=74). Three patients were excluded because of insufficient data.

MAIN RESULTS

Among the polymorphic variants examined, the MTHFR 677T-1298A haplotype was, upon univariate analysis, the only variable found associated with tumor regression (P=0.004). Moreover, at multivariate analysis, the MTHFR 677T-1298A haplotype was an independent predictor of tumor regression. Patients not carrying the MTHFR 677T-1298A haplotype (odds ratio 0.29, 95% confidence interval 0.13-0.64, P=0.002) displayed a higher response rate than patients with the MTHFR 677T-1298A haplotype.

CONCLUSIONS

Unlike TS VNTR and SNP polymorphisms, MTHFR 677T-1298A haplotype in genomic DNA has the potential to be a predictive marker of tumor response in rectal cancer patients submitted to preoperative chemoradiotherapy.

Efficacy of S-1 for patients with peritoneal metastasis of gastric cancer

BACKGROUND

This study was designed to examine the efficacy and compliance of S-1 for the patients with peritoneal metastasis of gastric cancer.

METHODS

Sixteen consecutive patients with peritoneal metastasis of gastric cancer were treated with S-1. Their survival was compared with that of the historical control group (25 patients). Thymidylate synthase, dihydropyrimidine dehydrogenase, thymidine phosphorylase and orotate phosphoribosyl transferase mRNA expression in the tumor were evaluated.

RESULTS

The median survival time of S-1-treated patients was 550 days, which was significantly longer than that of the historical control group (215 days). We elucidated some factors to prolong the survival of the patients treated with S-1 for peritoneal metastasis: peritoneal metastasis without other distant metastases, the combination of S-1 treatment and gastrectomy, and low expression of thymidine phosphorylase mRNA in primary tumors.

CONCLUSIONS

S-1 showed a surprisingly long-term survival with minimum toxicity in patients with peritoneal metastasis of gastric cancer.

Thymidine phosphorylase expression is associated with response to capecitabine plus irinotecan in patients with metastatic colorectal cancer

PURPOSE

To evaluate the clinical activity and toxicity of capecitabine plus irinotecan as first-line therapy for patients with metastatic colorectal cancer (mCRC), and to describe the association of expression of thymidine phosphorylase (TP), thymidylate synthase (TS), and dihydropyrimidine dehydrogenase (DPD) with antitumor activity.

PATIENTS AND METHODS

Patients with previously untreated mCRC received irinotecan days 1 and 8 intravenously, and capecitabine days 2 to 15 orally in 21-day cycles. Doses were irinotecan 125 mg/m2 and capecitabine 1,000 mg/m2 bid (n = 15; cohort 1), or irinotecan 100 mg/m2 and capecitabine 900 mg/m2 bid (n = 52; cohort 2). Tissues from primary and metastatic sites were assessed for TP, TS, and DPD gene and protein expression.

RESULTS

An unacceptable level of GI toxicity in the first 15 patients led to a protocol modification in starting doses. The response rate was 45% (30 of 67 patients). Overall survival was associated with TP expression assessed by immunohistochemistry in both primary tumors (P = .045) and metastases (P = .001). Objective tumor response was associated with TP expression in primary tumors (odds ratio, 4.77; 95% CI, 1.25 to 18.18), with a similar trend in metastases (odds ratio, 8.67; 95% CI, 0.95 to 79.1). TP gene expression in primary tumors was also associated with response.

CONCLUSION

These data indicate that capecitabine plus irinotecan is an active regimen against mCRC. The biomarker analysis (including metastatic tissue) was feasible in a multicenter setting, and provides preliminary evidence that TP expression may be a predictive marker for response.

The effect of surgically induced ischaemia on gene expression in a colorectal cancer xenograft model

Delays in tissue fixation following tumour vascular clamping and extirpation may adversely affect subsequent protein and mRNA analysis. This study investigated the effect of surgically induced ischaemia in a xenograft model of a colorectal cancer on the expression of a range of prognostic, predictive, and hypoxic markers, with a particular emphasis on thymidylate synthase. Vascular occlusion of human tumour xenografts by D-shaped metal clamps permitted defined periods of tumour ischaemia. Alterations in protein expression were measured by immunohistochemistry and spectral imaging, and changes in mRNA were measured by reverse transcriptase–polymerase chain reaction. Thymidylate synthase expression decreased following vascular occlusion, and this correlated with cyclin A expression. A similar reduction in dihydropyrimidine dehydrogenase was also seen. There were significant changes in the expression of several hypoxic markers, with carbonic anhydrase-9 showing the greatest response. Gene transcriptional levels were also noted to change following tumour clamping. In this xenograft model, surgically induced tumour ischaemia considerably altered the gene expression profiles of several prognostic and hypoxic markers, suggesting that the degree of tumour ischaemia should be minimised prior to tissue fixation.

Association of pretherapeutic expression of chemotherapy-related genes with response to neoadjuvant chemotherapy in Barrett carcinoma

PURPOSE

We analyzed pretherapeutic gene expression patterns of patients with locally advanced adenocarcinomas of the esophagus with regard to response to neoadjuvant chemotherapy.

EXPERIMENTAL DESIGN

Pretherapeutic, paraffin-embedded, formalin-fixed endoscopic esophageal tumor biopsies of 38 patients with locally advanced esophageal adenocarcinomas (Barrett adenocarcinoma) were included. All patients underwent two cycles of cisplatin and 5-fluorouracil (5-FU) therapy with or without additional paclitaxel followed by abdominothoracal esophagectomy. RNA expression levels of 5-FU metabolism-associated genes thymidylate synthase, thymidine phosphorylase, dihydropyrimidine dehydrogenase, methylenetetrahydrofolate reductase, MAP7, and ELF3, of platinum- and taxane-related genes caldesmon, ERCC1, ERCC4, HER-2/neu, and GADD45, and of multidrug resistance gene MRP1 were determined using real-time reverse transcriptase-PCR. Expression levels were correlated with response to chemotherapy, histopathologically assessed in surgically resected specimens.

RESULTS

Responding patients showed significantly higher pretherapeutic expression levels of MTHFR (P = 0.012), caldesmon (P = 0.016), and MRP1 (P = 0.007). In addition, patients with high pretherapeutic MTHFR and MRP1 levels had a survival benefit after surgery (P = 0.013 and P = 0.015, respectively). Additionally, investigation of intratumoral heterogeneity of gene expression of relevant genes (MTHFR, caldesmon, HER-2/neu, ERCC4, and MRP1), verified in nine untreated Barrett adenocarcinomas by examination of five distinct tumor areas, revealed no significant heterogeneity in gene expression indicating that expression profiles obtained from biopsy material may yield a representative genetic expression profile of total tumor tissue.

CONCLUSIONS

Our results indicate that determination of mRNA levels of few genes may be useful for the prediction of the success of neoadjuvant chemotherapy in individual cancer patients with locally advanced Barrett adenocarcinoma.

Tumor quantification of several fluoropyrimidines resistance gene expression with a unique quantitative RT-PCR method. Implications for pretherapeutic determination of tumor resistance phenotype

Pretherapeutic determination of tumor resistance to chemotherapy is a main challenge, hindered by the low number of mechanisms characterized at the same time, the small size of the clinical specimens and the heterogeneity of the techniques or the lack of true quantification. The aim of the present study was to determine in real time quantitative RT-PCR, tumor cell expression of several transcripts involved in cancer cell resistance with a unique cDNA sample from a tumor biopsy. The technique had to be suitable in clinical practice for determination of several factors involved in resistance to a given drug family, for example, fluoropyrimidines resistance factors: thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine kinase (TK), dihydrofolate reductase (DHFR), folylpolyglutamate synthetase (FPGS). A frame-shifted artificial construct was designed specifically to work within the same conditions. We validated our technique by quantifying expressions of these 5 genes starting from tissue samples of colorectal carcinoma and the surrounding normal mucosa of 33 different patients. That real time quantitative RT-PCR technique using the frame-shifted artificial construct as a standard provided a real comparison and quantification of different resistance factors. Tumor resistance phenotype determination based on that approach will be investigated in a control study.

Phase II study of tailored chemotherapy for advanced colorectal cancer with either 5-fluouracil and leucovorin or oxaliplatin and irinotecan based on the expression of thymidylate synthase and dihydropyrimidine dehydrogenase

BACKGROUND

Thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) are essential enzymes for 5-fluorouracil (5-FU) metabolism. In patients with advanced colorectal cancer (ACRC), retrospective studies have shown that low expression levels of TS and DPD correlated with response to 5-FU. We performed a prospective study in which the choice of first-line chemotherapy with either 5-FU or a non-5-FU containing regimen was based on TS and DPD expression.

PATIENTS AND METHODS

Fresh-frozen samples of metastases were obtained from 58 previously untreated patients with ACRC. mRNA expression of TS and DPD was quantified using an RT-PCR assay. Patients with low tumor expression of both TS and DPD received weekly bolus 5-FU/leucovorin (LV) 500 mg/m2 (group A); patients with high TS and/or DPD received 3-weekly oxaliplatin 85 mg/m2 and irinotecan 200 mg/m2 (group B). After progression, cross-over to the alternative regimen was attempted.

RESULTS

Of 53 eligible patients, 31 had tumors with both low TS and low DPD, and were treated in group A. A response was observed in 11 patients [35%; 95% confidence interval (CI) 19% to 54%]. Cross-over to second-line oxaliplatin/irinotecan resulted in a partial response in two out of 16 patients (13%; 95% CI 1% to 38%). In group B, four out of 22 patients responded (18%; 95% CI 5% to 40%), while no responses were observed in 12 patients after cross-over to 5-FU/LV (0%; 95% CI 0% to 28%).

CONCLUSIONS

Prospective selection of 5-FU/LV chemotherapy based on low TS and DPD expression in patients with ACRC did not confirm the high response rates reported in retrospective studies. The procedure of obtaining metastatic tissue and quantitation of enzymes appeared feasible but cumbersome. Before assessing the clinical utility of a predictive marker in a randomized trial, future studies should focus on prospective validation of the assay in a large and well defined population.

Treatment for multiple bilobar liver metastases of colorectal cancer

BACKGROUND

Recent advances have extended indications for hepatectomy to include multiple bilobar colorectal liver metastases (CLM). Staging systems based on the biological malignancy of primary and metastatic tumors provide appropriate indications for hepatectomy in CLM. However, suitability for resection in patients with complex and extensive hepatic metastases is controversial.

METHODS

A medline search was performed to identify papers reporting the resection for CLM. Techniques, indication, and results were reviewed.

RESULTS

If the anticipated remnant liver volume is small (25-40% of total), suggesting a high risk of postoperative liver failure, portal vein embolization (PVE) is recommended prior to hepatectomy. However, curative resections are not always possible. Specifically in synchronous multiple bilobar CLM, two-stage hepatectomy, comprising bilateral hepatectomy and primary resection with or without PVE, can prevent growth of ipsilateral metastatic nodules in the remnant liver and reduce surgical risk. Several local ablation techniques can complement surgery if hepatic resection alone increases the risk of postoperative liver failure or is not curative. Chemotherapy combined with targeted treatment can suppress recurrence and extend indications for hepatectomy by reducing the size and number of primary irresectable tumors.

CONCLUSION

PVE or staged procedure combining with local ablation or neoadjuvant, downstaging or adjuvant therapies extends indications for hepatectomy to include multiple bilobar CLM. The 5-year survival rate for multiple bilobar CLM treated with alternating hepatectomy and chemotherapy is comparable to the values reported for single and hemilateral CLM.

Predictive value of thymidylate synthase and dihydropyrimidine dehydrogenase protein expression on survival in adjuvantly treated stage III colon cancer patients

BACKGROUND

The predictive value of thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) expression on long-term survival by influencing 5-fluorouracil (5-FU) effect were determined in primary tumours and node metastases of stage III colon cancer patients treated adjuvantly with 5-FU regimens (n=391). The effect of TP 53 mutation status, which is thought to be functionally linked to TS inhibition, was also examined.

PATIENTS AND METHODS

TS and DPD protein expression was determined by immunohistochemical analysis using tissue microarrays of these colon tumours. Two hundred and twenty tumours had already been screened in a previous study for TP 53 mutations.

RESULTS

Low TS protein levels in primary stage III colon tumours appeared to be associated with mucinous histology and low DPD protein levels with young age at time of randomisation. Concordance between TS and DPD expression in primary and metastatic tumours was low. No associations were found between disease-free survival (DFS) and TS or DPD protein levels. When stratified by TP 53 mutation status DFS did not differ with TS expression.

CONCLUSIONS

Expression of TS and DPD proteins is not predictive for survival in patients with stage III colon cancer treated adjuvantly with 5-FU regimens. TS protein levels did not alter the effect of TP 53 mutation status.

Methylenetetrahydrofolate reductase gene polymorphisms and response to fluorouracil-based treatment in advanced colorectal cancer patients

Methylenetetrahydrofolate reductase (MTHFR) controls intracellular CH2FH4 concentrations (required for optimal fluoropyrimidine efficacy) by irreversibly converting CH2FH4 into 5-methyltetrahydrofolate. MTHFR 677C>T and 1298A>C polymorphisms are linked to altered enzyme activity. Thus, mutated MTHFR tumours should, in theory, be more sensitive to 5-fluorouracil (5FU) than wild-type tumours. MTHFR polymorphisms in position 677 and 1298 were analysed in 98 colorectal cancer patients with unresectable liver metastases (57 men, 41 women, mean age 64 years) receiving 5FU-folinic acid. 677C>T and 1298A>C genotypes were determined simultaneously by melting curve analyses on liver metastases. 677C>T genotype distribution was 46.9% wt/wt, 34.7% wt/mut and 18.4% mut/mut; that of 1298A>C was 52.0% wt/wt, 35.7% wt/mut and 12.3% mut/mut. The response rate was not related to 1298A>C genotype but was significantly linked to 677C>T genotype (response rate: 40%, 21% and 56% in wt/wt, wt/mut and mut/mut, respectively; P = 0.040), with an increased response rate in mut/mut tumours relative to wt/wt (odds ratio = 1.88). Thymidylate synthase activity measured in metastases was a significant predictor of 5FU responsiveness and the addition of the 677C>T genotype improved model prediction. MTHFR 1298A>C polymorphism was significantly linked to specific survival, with homozygous mutated patients having the worst prognosis (P = 0.009, relative risk = 2.48 in mut/mut versus wt/wt). MTHFR 1298A>C genotype remained a significant predictor in a multivariate analysis including metastasis characteristics. The results suggest that MTHFR genotypes are relevant and independent factors of patient outcome in 5FU-based treatment of advanced colorectal cancer.

The rTS Signaling Pathway as a Target for Drug Development

The rTS gene was discovered because it codes for a complementary (antisense) RNA to the messenger RNA for thymidylate synthase (TS). It was later shown that rTS also encodes 2 proteins, rTSa and rTSb. Recently, it has become apparent that rTSb overexpression can cause the downregulation of TS protein in a colon cancer cell line through the production of > or = 1 previously unknown signaling molecules. This observation signified the presence of a previously unidentified signaling pathway. The existence of a signaling pathway that can regulate TS protein levels and the widespread expression of the rTSb protein suggests that a new target for drug development may be on the horizon. This review describes the relationship between the rTS and TS genes and the known and potential effects of rTS RNAs and rTS proteins. We also present the structure of an identified TS downregulatory compound that may serve as a lead compound for development.