Capecitabine in the treatment of esophageal and gastric cancers

Nanopore Signatures of Nucleoside Drugs

Nucleoside drugs, which are analogues of natural nucleosides, have been widely applied in the clinical treatment of viral infections and cancers. The development of nucleoside drugs, repurposing of existing drugs, and combined use of multiple drug types have made the rapid sensing of nucleoside drugs urgently needed. Nanopores are emerging single-molecule sensors that have high resolution to resolve even minor structural differences between chemical compounds. Here, an engineered Mycobacterium smegmatis porin A hetero-octamer was used to perform general nucleoside drug analysis. Ten nucleoside drugs were simultaneously detected and fully discriminated. An accuracy of >99.9% was consequently reported. This sensing capacity was further demonstrated in direct nanopore analysis of ribavirin buccal tablets, confirming its sensing reliability against complex samples and environments. No sample separation is needed, however, significantly minimizing the complexity of the measurement. This technique may inspire nanopore applications in pharmaceutical production and pharmacokinetics measurements.

Efficacy of Postoperative FOLFOX Versus XELOX Chemotherapy for Gastric Cancer and Prognostic Value of Platelet-Lymphocyte Ratio in Patients Receiving XELOX

Background

Surgery combined with postoperative chemotherapy is an effective method for treating patients with gastric cancer (GC) in Asia. The important roles of systemic inflammatory response in chemotherapy have been gradually verified. The purpose of this study was to assess the difference in clinical effectiveness of FOLFOX (oxaliplatin + leucovorin + 5-fluorouracil) and XELOX (oxaliplatin + capecitabine), and the prognostic value of postoperative platelet–lymphocyte ratio (PLR) in the XELOX group.

Methods

Patients who received radical gastrectomy combined with postoperative chemotherapy between 2004 and 2014 were consecutively selected into the FOLFOX and XELOX groups. Group bias was reduced through propensity score matching, which resulted in 278 patients in each group. Cut-off values of systemic immune inflammation (SII) score and PLR were obtained by receiver operating characteristic curve. Kaplan–Meier and Log-rank tests were used to analyze overall survival. The chi-square test was used to analyze the association between clinical characteristics and inflammatory indexes. Univariate and multivariate analyses based on Cox regression analysis showed independent risk factors for prognosis. The nomogram was made by R studio.

Results

Patients receiving XELOX postoperative chemotherapy had better survival than those receiving FOLFOX (P < 0.001), especially for stage III GC (P = 0.002). Preoperative SII was an independent risk factor for prognosis in the FOLFOX group, and PLR of the second postoperative chemotherapy regimen in the XELOX group, combined with tumor size and pTNM stage, could construct a nomogram for evaluating recurrence and prognosis.

Conclusion

XELOX is better than FOLFOX for treatment of GC in Chinese patients, and a nomogram constructed by PLR, tumor size and pTNM stage can predict recurrence and prognosis.

Human Thymidylate Synthase Inhibitors Halting Ovarian Cancer Growth

Human thymidylate synthase (hTS) has an important role in DNA biosynthesis, thus it is essential for cell survival. TS is involved in the folate pathways, specifically in the de novo pyrimidine biosynthesis. Structure and functions are intimately correlated, account for cellular activity and, in a broader view, with in vivo mechanisms. hTS is a target for anticancer agents, some of which are clinical drugs. The understanding of the detailed mechanism of TS inhibition by currently used drugs and of the interaction with the mechanism of action of other anticancer agents can suggest new perspective of TS inhibition able to improve the anticancer effect and to overcome drug resistance. TS-targeting drugs in therapy today are inhibitors that bind at the active site and that mostly resemble the substrates. Nonsubstrate analogs offer an opportunity for allosteric binding and novel mode of inhibition in the cancer cells. This chapter illustrates the relationship among the large number of hTS actions at molecular and clinical levels, its role as a target for ovarian cancer therapy, in particular in cases of overexpression of hTS and other folate proteins such as those induced by platinum drug treatments, and address the potential combination of TS inhibitors with other suitable anticancer agents.

Safety, Feasibility, and Efficacy of Capecitabine Maintenance in Patients With Advanced Gastric Cancer: A Retrospective Study

Gastric cancer is still one of the cancers with highest mortality. Most patients present with advanced-stage disease. Palliative chemotherapy is usually the only treatment option for patients with advanced gastric cancer (AGC). Maintenance chemotherapy is an evolving concept in medical oncology. Maintenance chemotherapy can be administered with the same drug(s) in the initial regimen or with an alternative agent. In this article, we report our experience with capecitabine as a maintenance agent for patients with AGC. No treatment-related death was observed due to use of capecitabine. Median progression-free survival was 10.4 months, and median overall survival was 19.7 months. Activity and toxicity profile of capecitabine seems favorable as a maintenance agent in AGC. We believe that capecitabine deserves further trials as a maintenance agent for patients with AGC.

Radiation recall after capecitabine in a patient with recurrent nasopharyngeal carcinoma: a case report

Background

Capecitabine has been commonly used in recurrent or metastatic nasopharyngeal carcinoma. However, radiation recall after capecitabine for nasopharyngeal carcinoma has not been reported.

Case presentation

We report the case of a 64-year-old Chinese woman with locoregionally advanced nasopharyngeal carcinoma previously treated with induction chemotherapy followed by concurrent chemoradiation 6 years ago. She developed cervical, mediastinal, and abdominal nodal relapses 14 months later. She then received capecitabine with initial excellent tumor response for 1 year but disease recurrence was noticed at the peripancreatic nodal region, which was successfully treated with concurrent chemoradiation with capecitabine. Unfortunately, she developed progressive erythema of the face and neck region at exactly the previous irradiation site for her initial nasopharyngeal carcinoma, 2 months after taking capecitabine. She initially ignored it, but it became more confluent and serious. Eventually, a facial skin biopsy was performed showing nonspecific chronic inflammation only. The diagnosis was most likely radiation recall phenomenon since capecitabine was the only drug she received before development of this dermatological manifestation on her previously irradiated face and neck. Treatment was conservative and supportive albeit with no significant clinical improvement.

Conclusions

Radiation oncologists should be aware of this potential risk of capecitabine, especially when it is administered for a long period of time.

Inside the biochemical pathways of thymidylate synthase perturbed by anticancer drugs: Novel strategies to overcome cancer chemoresistance

Our current understanding of the mechanisms of action of antitumor agents and the precise mechanisms underlying drug resistance is that these two processes are directly linked. Moreover, it is often possible to delineate chemoresistance mechanisms based on the specific mechanism of action of a given anticancer drug. A more holistic approach to the chemoresistance problem suggests that entire metabolic pathways, rather than single enzyme targets may better explain and educate us about the complexity of the cellular responses upon cytotoxic drug administration. Drugs, which target thymidylate synthase and folate-dependent enzymes, represent an important therapeutic arm in the treatment of various human malignancies. However, prolonged patient treatment often provokes drug resistance phenomena that render the chemotherapeutic treatment highly ineffective. Hence, strategies to overcome drug resistance are primarily designed to achieve either enhanced intracellular drug accumulation, to avoid the upregulation of folate-dependent enzymes, and to circumvent the impairment of DNA repair enzymes which are also responsible for cross-resistance to various anticancer drugs. The current clinical practice based on drug combination therapeutic regimens represents the most effective approach to counteract drug resistance. In the current paper, we review the molecular aspects of the activity of TS-targeting drugs and describe how such mechanisms are related to the emergence of clinical drug resistance. We also discuss the current possibilities to overcome drug resistance by using a molecular mechanistic approach based on medicinal chemistry methods focusing on rational structural modifications of novel antitumor agents. This paper also focuses on the importance of the modulation of metabolic pathways upon drug administration, their analysis and the assessment of their putative roles in the networks involved using a meta-analysis approach. The present review describes the main pathways that are modulated by TS-targeting anticancer drugs starting from the description of the normal functioning of the folate metabolic pathway, through the protein modulation occurring upon drug delivery to cultured tumor cells as well as cancer patients, finally describing how the pathways are modulated by drug resistance development. The data collected are then analyzed using network/netwire connecting methods in order to provide a wider view of the pathways involved and of the importance of such information in identifying additional proteins that could serve as novel druggable targets for efficacious cancer therapy.

p16 Methylation is associated with chemosensitivity to fluorouracil in patients with advanced gastric cancer

No effective biomarkers have been confirmed to predict chemosensitivity for patients with gastric cancer. The purpose of this study was to investigate whether DNA methylation is associated with chemosensitivity in patients with gastric cancer. Tumors and matched non-tumor biopsy tissues collected from 134 advanced gastric cancer (AGC) patients prior to fluorouracil-based chemotherapy were retrospectively analyzed. The methylation status of p16, E-cadherin (CDH1), MGMT (O-6-methylguanine-DNA methyltransferase), and human mutL homolog 1 (hMLH1) was evaluated using a Methylight assay, and the association between p16 methylation and the sensitivity of 5-fluorouracil in cell lines was determined by in vitro assay. The methylation of p16 (17.9 vs. 0 %, P = 0.002), CDH1 (20.9 vs. 2.2 %, P < 0.001), MGMT (17.9 vs. 0 %, P = 0.052), and hMLH1 (14.9 vs. 2.2 %, P = 0.024) was more common in gastric cancer tissues (n = 134) than in non-tumor tissues (n = 46). For all patients, a reverse correlation was only found between p16 methylation and clinical response (P = 0.017), which suggested that p16 methylation might be associated with chemosensitivity of fluorouracil in gastric cancer patients. Results from in vitro experiments demonstrated that p16 methylation was closely correlated with the sensitivity of 5-fluorouracil in gastric cancer cells. The present results indicated that the methylation of p16, CDH1, MGMT, and hMLH1 was both frequent and specific in gastric cancer tissues. p16 Methylation might be used to predict chemosensitivity of fluorouracil for patients with AGC when validated in large samples in the future.