Role of dihydropyrimidine dehydrogenase inhibitory fluoropyrimidine against non-small cell lung cancer—in correlation with the tumoral expression of thymidylate synthase and dihydropyrimidine dehydrogenase

Intratumoral gene expression of dihydrofolate reductase and folylpoly-c-glutamate synthetase affects the sensitivity to 5-fluorouracil in non-small cell lung cancer

BACKGROUND

Various factors related to the sensitivity of non-small cell lung carcinoma (NSCLC) to 5-fluorouracil (5-FU) have been reported, and some of them have been clinically applied. In this single-institutional prospective analysis, the mRNA expression level of five folic acid-associated enzymes was evaluated in surgical specimens of NSCLC. We investigated the correlation between the antitumor effect of 5-FU in NSCLC using an anticancer drug sensitivity test and the gene expression levels of five enzymes.

MATERIALS AND METHODS

Forty patients who underwent surgery for NSCLC were enrolled, and the antitumor effect was measured using an in vitro anticancer drug sensitivity test (histoculture drug response assay) using freshly resected specimens. In the same sample, the mRNA expression levels of five enzymes involved in the sensitivity to 5-FU were measured in the tumor using real-time PCR. The expression levels and the result of the sensitivity test were compared.

RESULTS

No correlation was found between dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyltransferase (OPRT), or DPD/OPRT expression and the antitumor effects of 5-FU. On the other hand, a correlation was found between thymidylate synthase (TS), folylpoly-c-glutamate synthetase (FPGS), and dihydrofolate reductase (DHFR) expression and 5-FU sensitivity.

CONCLUSION

Expression of FPGS and DHFR may be useful for predicting the efficacy of 5-FU-based chemotherapy for NSCLC.

A phase II study of S-1 in relapsed small cell lung cancer

S-1 is a new oral fluoropyrimidine derivative designed to enhance anticancer activity and reduce gastrointestinal toxicity. This phase II trial aimed to evaluate S-1 in patients with relapsed small cell lung cancer (SCLC). SCLC patients who had experienced treatment failure with ≥1 prior chemotherapies were eligible. Patients were required to have an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0-2 and adequate organ function. Treatment consisted of oral S-1 at 40 mg/m² twice/day for 28 days every 6 weeks. Twenty-six patients were enrolled, 85% of whom were males. The median age was 68 years (range, 33-79) and 81% of the patients had a performance status of 0-1, and 46% of the patients had relapse-sensitive SCLC. An objective response was obtained in only 1 patient (3.8%), and the median progression-free survival (PFS) was 1.1 months. The median overall survival was 5.3 months, and the 1-year survival rate was 23%. The most common grade 3/4 toxicities included neutropenia (7.7%), leukopenia (7.7%), anemia (7.7%), hyponatremia (7.7%), rash (7.7%), infection (7.7%) and diarrhoea (3.8%). None of the patients developed febrile neutropenia and no deaths were attributed to treatment. In conclusion, S-1 has minimal single-agent activity in relapsed SCLC.

Targeting miR-21 enhances the sensitivity of human colon cancer HT-29 cells to chemoradiotherapy in vitro

5-Fluorouracil (5-FU) is a classic chemotherapeutic drug that has been widely used for colorectal cancer treatment, but colorectal cancer cells are often resistant to primary or acquired 5-FU therapy. Several studies have shown that miR-21 is significantly elevated in colorectal cancer. This suggests that this miRNA might play a role in this resistance. In this study, we investigated this possibility and the possible mechanism underlying this role. We showed that forced expression of miR-21 significantly inhibited apoptosis, enhanced cell proliferation, invasion, and colony formation ability, promoted G1/S cell cycle transition and increased the resistance of tumor cells to 5-FU and X radiation in HT-29 colon cancer cells. Furthermore, knockdown of miR-21 reversed these effects on HT-29 cells and increased the sensitivity of HT-29/5-FU to 5-FU chemotherapy. Finally, we showed that miR-21 targeted the human mutS homolog2 (hMSH2), and indirectly regulated the expression of thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD). These results demonstrate that miR-21 may play an important role in the 5-FU resistance of colon cancer cells.

Association between TYMS expression and efficacy of pemetrexed-based chemotherapy in advanced non-small cell lung cancer: a meta-analysis

Background

The predictive value of thymidylate synthase (TYMS) to sensitivity to pemetrexed-based chemotherapy in advanced non-small cell lung cancer (NSCLC) patients is controversial. We conducted a meta-analysis of all relevant published data to assess the association of TYMS expression with the clinical outcomes of pemetrexed-based regimen in advanced NSCLC.

Patients and Methods

We conducted an electronic search using using PubMed, Embase, OVID and Cochrane Library databases and manual search. Pooled odds ratio (OR) for the response rate and hazard ratio (HR) for the overall survival and progression free survival were calculated using the software Revman 5.0.

Results

There were 11 studies (n=798) met our criteria for evaluation. Response rate to pemetrexed-based regimen was significantly higher in patients with low/negative TYMS (OR=2.96, 95%CI [1.81, 4.86] P<0.0001). Patients with low/negative TYMS who were treated with pemetrexed-based regimen had longer progression free survival (HR 0.50, 95%CI [0.41, 0.61] P <0.00001) and overall survival (HR 0.41, 95%CI [0.22, 0.78] P=0.007) than those with high/positive TYMS.

Conclusions

Low/negative TYMS expression was significantly associated with higher response rate, longer median survival and longer progression free survival for advanced NSCLC patients receiving pemtrexed-based chemotherapy. Hence, TYMS may be a potential predictor of sensitivity to pemtrexed-based chemotherapy in advanced NSCLC. Large scale prospective clinical trials are still warranted.

Dihydropyrimidine dehydrogenase (DPD) expression is negatively regulated by certain microRNAs in human lung tissues

Dihydropyrimidine dehydrogenase (DPD) is important to the antitumor effect of 5-fluorouracil (5-FU). DPD gene (DPYD) expression in tumors is correlated with sensitivity to 5-FU. Because the 5-FU accumulated in cancer cells is also rapidly converted into inactivated metabolites through catabolic pathways mediated by DPD, high DPD activity in cancer cells is an important determinant of the response to 5-FU. DPD activity is highly variable and reduced activity causes a high risk of 5-FU toxicity. Genetic variation in DPYD has been proposed as the main factor responsible for the variation in DPD activity. However, only a small proportion of the activity of DPD can be explained by DPYD mutations. In this study, we found that DPYD is a target of the following microRNAs (miRNA): miR-27a, miR-27b, miR-134, and miR-582-5p. In luciferase assays with HepG2 cells, the overexpression of these miRNAs was associated with significantly decreased reporter activity in a plasmid containing the 3'-UTR of DYPD mRNA. The level of DPD protein in MIAPaca-2 cells was also significantly decreased by the overexpression of these four miRNAs. The results suggest that miR-27a, miR-27b, miR-134, and miR-582-5p post-transcriptionally regulate DPD protein expression. The levels of miRNAs in normal lung tissue and lung tumors were compared; miR-27b and miR-134 levels were significantly lower in the tumors than normal tissue (3.64 ± 4.02 versus 9.75 ± 6.58 and 0.64 ± 0.75 versus 1.48 ± 1.39). DPD protein levels were significantly higher in the tumors. Thus, the decreased expression of miR-27b would be responsible for the high levels of DPD protein. This study is the first to show that miRNAs regulate the DPD protein, and provides new insight into 5-FU-based chemotherapy.

The therapeutic efficacy of S-1 against orthotopically implanted human pleural mesothelioma cells in severe combined immunodeficient mice

Purpose

Malignant pleural mesothelioma (MPM) is a highly lethal neoplasm. S-1 has been developed as a novel oral antineoplastic agent based on the modulation of 5-fluorouracil (5-FU) bioactivity. This study was conducted to investigate the preclinical therapeutic effect of S-1 on MPM.

Methods

We used three human MPM cell lines, Y-MESO-14, NCI-H290 and MSTO-211H. In vitro proliferation of human MPM cells was determined by MTT assay. Human MPM cells were orthotopically implanted into thoracic cavity of SCID mice. Tumor-bearing mice were treated with S-1 or vehicle.

Results

The combination of 5-FU and 5-chloro-2,4-dihydroxypyridine (CDHP) was more effective than 5-FU alone in inhibiting MPM cell proliferation in vitro. This combination was most effective in Y-MESO-14 cells, which co-expressed high protein level of dihydropyrimidine dehydrogenase (DPD) and thymidine phosphorylase (TP). In vivo data showed that treatment with S-1 significantly reduced thoracic tumors and pleural effusion produced by Y-MESO-14 cells. Moreover, treatment with S-1 prolonged the survival of Y-MESO-14 cell-bearing SCID mice.

Conclusions

We demonstrated that S-1 was effective for inhibiting the proliferation of MPM cells, particularly with both DPD and TP expressions, suggesting that S-1 might be therapeutically effective for control of MPM.

Histone deacetylase inhibitor enhances sensitivity of non-small-cell lung cancer cells to 5-FU/S-1 via down-regulation of thymidylate synthase expression and up-regulation of p21(waf1/cip1) expression

It is desirable to find more appropriate therapeutic opportunities in non-small-cell lung cancer (NSCLC) due to the current poor prognosis of affected patients. Recently, several histone deacetylase (HDAC) inhibitors, including suberoylanilide hydroxamic acid (SAHA), have been reported to exhibit antitumor activities against NSCLC. S-1, a novel oral fluorouracil anticancer drug, has been developed for clinical use in the treatment of NSCLC in Japan. Using an MTT assay, we analyzed the growth-inhibitory effect of 5-fluorouracil (5-FU), S-1, and SAHA against three NSCLC cell lines, as well as the breast cancer cell line MCF7 which is known to be highly sensitive to 5-FU. Combined treatment with low-dose SAHA enhanced 5-FU- and S-1-mediated cytotoxicity and resulted in synergistic effects, especially in 5-FU-resistant cells. Both the mRNA and protein expression levels of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and orotate phosphoribosyltransferase (OPRT), which are associated with 5-FU sensitivity/response, were analyzed in the cells undergoing treatment. 5-Fluorouracil-resistant lung cancer cells displayed high expression of TS mRNA and protein. Suberoylanilide hydroxamic acid down-regulated TS mRNA and protein expression, as well as repressed the rapid induction of this factor during 5-FU treatment, in all examined cell types. We also examined the status of the Rb-E2F1 pathway, with SAHA up-regulating p21(waf1/cip1) expression via promoter histone acetylation; this, in turn, blocked the Rb-E2F1 pathway. We conclude that combination therapy with SAHA and S-1 in lung cancer may be promising due to its potential to overcome S-1 resistance via modulation of 5-FU/S-1 sensitivity-associated biomarker (TS) by HDAC inhibitor.

The efficacy of pemetrexed as a third- or fourth-line therapy and the significance of thymidylate synthase expression in patients with advanced non-small cell lung cancer

BACKGROUND

Pemetrexed is one of the standard second-line therapies in advanced non-small cell lung cancer (NSCLC). Currently, there are no standard cytotoxic treatments beyond second-line therapy. We evaluated the efficacy and safety of pemetrexed as a salvage regimen in heavily pretreated NSCLC patients. We also analyzed thymidylate synthase (TS) expression in tumor tissues to determine whether TS expression is correlated with the clinical efficacy of pemetrexed.

METHODS

One hundred and ten NSCLC patients who received pemetrexed as third- or fourth-line therapy at the Samsung Medical Center between June 2006 and June 2008 were retrospectively reviewed. TS expression was analyzed by immunohistochemical staining in 55 NSCLC tissue specimens. The relationships between TS expression and clinicopathological factors were evaluated. Univariate and multivariate analyses were performed to define the predictive factors and prognostic significances.

RESULTS

The median age of patients in this study was 59 years (range: 24-84), 50.9% were men, and 27 (24.6%) were smokers or previous smokers. Sixty-five patients (59.1%) received pemetrexed as third-line treatment, and 95 (86.4%) had non-squamous cell carcinoma. Platinum-based chemotherapy (84.6%) was the most common first-line therapy, and EGFR TKIs [erlotinib (17.3%) or gefitinib (43.6%)] were a common second-line therapy. The median time from date of diagnosis to the date of the first pemetrexed treatment was 12.8 months (range: 1.8-62.2 months) and the median number of pemetrexed treatments was 4 (range 1-22). Eighteen patients achieved PR (16.3%), 41 patients SD (37.3%), and 43 patients PD (39.1%), with a disease control rate of 53.6%. The median follow-up duration was 16.1 months, the median progression-free survival (PFS) was 3.2 months (95% CI: 1.9-4.5 months), and the median overall survival (OS) was 11.6 months (95% CI: 9.0-14.1 months). Male gender was the only independent variable for poor PFS (HR=1.673, 95% CI: 1.103-2.535), with poor performance status (HR=2.454, 95% CI: 1.405-4.287) and history of smoking (HR=1.856, 95% CI: 1.087-3.168) being independent adverse factors for OS. Thirteen of 55 tumor tissues (23.6%) showed TS expression; however, there were no significant correlations between TS expression and the clinicopathological factors.

CONCLUSION

Pemetrexed was suggested as a third- or fourth-line therapy due to its favorable efficacy and tolerable toxicity. Further studies are warranted to define the adequate sequence of salvage treatments, especially in patients with adenocarcinoma lung cancer.

Tailor-made chemotherapy for non-small cell lung cancer patients

The selection of the most effective chemotherapy treatment based on evaluation of biomarkers, that is, 'tailor-made chemotherapy', can improve the clinical outcome of non-small cell lung cancer patients, including early-stage tumors with a high metastatic potential and advanced-stage tumors with a low proliferation rate. Therefore, treatment would be chosen according to which drugs would be most effective in combating specific tumors. For example: 5-fluorouracil-derived agents would be used for tumors with a low expression of thymidylate synthase; gefitinib and erlotinib for tumors with epidermal growth factor receptor (EGFR) mutations or increased EGFR gene copy numbers; cisplatin and carboplatin for tumors with a low expression of excision repair cross complementing-1; and gemcitabine for tumors with a low expression of ribonucleotide reductase. The remaining populations of non-small cell lung cancers require chemotherapy using other drugs based on an evaluation of other targeted molecules.