Raltitrexed-based chemotherapy for advanced colorectal cancer

Late-line options for patients with metastatic colorectal cancer: a review and evidence-based algorithm

Over the past few years, several novel systemic treatments have emerged for patients with treatment-refractory metastatic colorectal cancer, thus making selection of the most effective later-line therapy a challenge for medical oncologists. Over the past decade, regorafenib and trifluridine-tipiracil were the only available drugs and often provided limited clinical benefit compared to best supportive care. Results from subsequent practice-changing trials opened several novel therapeutic avenues, both for unselected patients (such as trifluridine-tipiracil plus bevacizumab or fruquintinib) and for subgroups defined by the presence of actionable alterations in their tumours (such as HER2-targeted therapies or KRASG12C inhibitors) or with no acquired mechanisms of resistance to the previously received targeted agents in circulating tumour DNA (such as retreatment with anti-EGFR antibodies). In this Review, we provide a comprehensive overview of advances in the field over the past few years and offer a practical perspective on translation of the most relevant results into the daily management of patients with metastatic colorectal cancer using an evidence-based algorithm. Finally, we discuss some of the most appealing ongoing areas of research and highlight approaches with the potential to further expand the therapeutic armamentarium.

Association of pre-existing cardiovascular disease with administration of fluoropyrimidine chemotherapy in patients with gastrointestinal malignancies

Objective

Fluoropyrimidine chemotherapy is a first-line treatment for many gastrointestinal (GI) cancers, however, cardiotoxicity concerns may limit administration in patients with pre-existing cardiovascular disease (CVD). This study investigated the association of pre-existing CVD with use of fluoropyrimidine chemotherapy in tumour-eligible GI cancer patients.

Methods and analysis

National cancer registry data from the Virtual Cardio-Oncology Research Initiative from England between 2014 and 2018 was used to identify GI cancer patients eligible to receive fluoropyrimidine chemotherapy. Linkage to Hospital Episode Statistics and CVD registry data were used to ascertain prior CVD and outcomes. Primary outcome was first administration of fluoropyrimidine chemotherapy following cancer diagnosis. Cox proportional hazard models determined HR and 95% CIs for the association between initiation of fluoropyrimidine treatment and prior CVD.

Results

112 726 eligible patients were identified (median age 71 years (IQR 62-80), 39.7% female). 33 026 (29.3%) had pre-existing CVD. 73 392 (65.1%) patients had a diagnosis of colorectal, 23 208 (20.6%) oesophageal, 14 788 (13.1%) gastric and 1338 (1.2%) small bowel cancer. Individuals with pre-existing CVD had a 27% reduced rate of receiving fluoropyrimidine chemotherapy (HR, 0.73; 95% CI 0.70 to 0.75) on multivariable analysis. Significantly reduced rates of fluoropyrimidine administration were found across all subtypes of pre-existing CVD.

Conclusions

GI cancer patients with all types of pre-existing CVD are less likely to receive fluoropyrimidine chemotherapy despite eligibility. This suggests widespread caution regarding administration of fluoropyrimidines across this population; further research is needed to assess whether such conservatism is justified.

A Clinical Study of Intraoperative Perfusion Chemotherapy With Raltitrexed in Colon Cancer: A Prospective Cohort Study

INTRODUCTION

Colorectal cancer (CRC) ranks as the second leading cause of cancer-related mortality among women and the third leading cause of cancer-associated mortality among men. Treatment of colon cancer is very crucial for a patient's survival. In this study, we assessed the reliability, efficacy, and safety of raltitrexed in intraoperative intraperitoneal chemotherapy for colon cancer.

METHODOLOGY

A total of 57 patients with clinical stages II and III of colon cancer were included in the study. R0 resection surgery + hyperthermic intraperitoneal chemotherapy (HIPEC) procedure was done with raltitrexed. It was given in a dose of 3 mg/m2 in a 0.9% NS injection in a volume of 500 milliliters. Postoperative complications were observed.

RESULT

The most common postoperative complication was nausea/vomiting, which was seen in 21 out of 57 patients (37%). The second most common complication was fever (18/57). None of the patients died or developed renal toxicity, hepatic toxicity, and intestinal obstruction.

CONCLUSION

Raltitrexed is a reliable, efficient, and safe drug and can be used in intraoperative intraperitoneal chemotherapy of colon cancer.

Loadability and Releasing Profiles In Vitro and Pharmacokinetics In Vivo of Vinorelbine and Raltitrexed by CalliSpheres Beads

Background: This study investigated the loadability and releasing profiles of vinorelbine and raltitrexed from CalliSpheres® Beads (CB) in vitro, and further explored the pharmacokinetic features of vinorelbine and raltitrexed eluting CB in vivo. Materials and Methods: Ten milligrams vinorelbine and 0.2 mg raltitrexed were mixed with 0.15 g CB at two sizes (100-300 and 300-500 μm) for 24 h, respectively, to measure the loadability. Then vinorelbine/raltitrexed loading CBs were placed in 20% phosphate-buffered saline for 24 h to measure the release profiles. Transcatheter arterial chemoembolization (TACE) with 1 mg vinorelbine eluting CBs (two sizes respectively) and transcatheter arterial hepatic infusion (TAI) with 1 mg vinorelbine were performed in 9 rabbits (3 rabbits in each group). The above experiments were repeated with 0.2 mg raltitrexed. Results: Vinorelbine loading efficiency quickly reached 90% within 10 min with maximum loadability >90% by CB with both two sizes, and vinorelbine release rate gradually increased to ∼100% within 1 h. Raltitrexed loading efficiency gradually increased to >40% within 15 min, then slowly increased to >60% within 24 h, with maximum loadability <70% by CB with both sizes, and raltitrexed release rate gradually increased to >90% within 1 h. Besides, vinorelbine/raltitrexed eluting CB showed greatly decreased maximum serum concentration (Cmax) of the drug compared with TAI in rabbits with similar area under the curve (0-t), mean residence time (0-t), and half-time (T1/2). Conclusion: CB exhibits good loadability and an acceptable releasing profile for eluting vinorelbine and raltitrexed, and shows lower Cmax and numerically stable concentration than TAI.

Cancer chemotherapy and beyond: Current status, drug candidates, associated risks and progress in targeted therapeutics

Cancer is an abnormal state of cells where they undergo uncontrolled proliferation and produce aggressive malignancies that causes millions of deaths every year. With the new understanding of the molecular mechanism(s) of disease progression, our knowledge about the disease is snowballing, leading to the evolution of many new therapeutic regimes and their successive trials. In the past few decades, various combinations of therapies have been proposed and are presently employed in the treatment of diverse cancers. Targeted drug therapy, immunotherapy, and personalized medicines are now largely being employed, which were not common a few years back. The field of cancer discoveries and therapeutics are evolving fast as cancer type-specific biomarkers are progressively being identified and several types of cancers are nowadays undergoing systematic therapies, extending patients' disease-free survival thereafter. Although growing evidence shows that a systematic and targeted approach could be the future of cancer medicine, chemotherapy remains a largely opted therapeutic option despite its known side effects on the patient's physical and psychological health. Chemotherapeutic agents/pharmaceuticals served a great purpose over the past few decades and have remained the frontline choice for advanced-stage malignancies where surgery and/or radiation therapy cannot be prescribed due to specific reasons. The present report succinctly reviews the existing and contemporary advancements in chemotherapy and assesses the status of the enrolled drugs/pharmaceuticals; it also comprehensively discusses the emerging role of specific/targeted therapeutic strategies that are presently being employed to achieve better clinical success/survival rate in cancer patients.

A Preliminary Study of Immediate Intraperitoneal Chemotherapy for Stage III Colorectal Cancer

OBJECTIVES

Investigate the survival of patients with stage III colorectal cancer (CRC) treated with immediate postoperative intraperitoneal chemotherapy.

METHODS

The clinical data of 195 patients with stage III CRC admitted to The First Affiliated Hospital of Wenzhou Medical University from June 2017 to June 2018 were retrospectively analyzed. The patients were divided into an observation group and a control group, both groups were treated with the routine laparoscopic radical operation, on the basis of which, the patients in the observation group were treated with intraperitoneal perfusion chemotherapy during the operation. The local recurrence, abdominal cavity metastasis, and liver metastasis were followed up, and the time of disease recurrence and total survival were recorded.

RESULTS

The survival analysis showed that there was a significant difference in progression-free survival (χ 2 = 5.416, P = 0.020) and overall survival (χ 2 = 4.673, P = 0.031) between the observation group and the control group.

CONCLUSIONS

During laparoscopic radical resection of CRC, the use of intraperitoneal chemotherapy with raltitrexed can achieve satisfactory results and improve the survival rate of patients with stage III CRC, perioperative use of raltitrexed has been shown to be beneficial in terms of overall survival and progression-free survival.

Folic Acid Antimetabolites (Antifolates): A Brief Review on Synthetic Strategies and Application Opportunities

Antimetabolites of folic acid represent a large group of drugs and drug candidates, including those for cancer chemotherapy. In this current review, the most common methods and approaches are presented for the synthesis of therapeutically significant antimetabolites of folic acid, which are Methotrexate (MTX), Raltitrexed (Tomudex, ZD1694), Pralatrexate, Pemetrexed, TNP-351, and Lometrexol. In addition, the applications or uses of these folic acid antimetabolites are also discussed.

Preliminary outcomes of raltitrexed eluting bead-transarterial chemoembolization using Callispheres® beads for gastrointestinal adenocarcinoma liver metastasis

Background

Drug-eluting bead transarterial chemoembolization (DEB-TACE) with Callispheres® beads (CB) is currently used in the treatment of hepatocellular carcinoma. However, clinical data regarding DEB-TACE using raltitrexed-eluting CB for gastrointestinal adenocarcinoma liver metastases (GALM) treatment is limited. We aimed to report the preliminary outcomes of DEB-TACE using CB in unresectable GALM patients.

Methods

This retrospective study enrolled unresectable GALM patients who were treated with DEB-TACE using raltitrexed-eluting CB from October 2018 to October 2021. Totally, 25 patients, 18 males and 7 females, mean age 66.8±9.5 years, were continuously enrolled. Postoperative treatment response, survival rates, and complication were calculated during the procedure and follow-up.

Results

Twenty-four patients were technically successful, with a technical success rate of 96.0%. The 3-month overall response rate and disease control rate were 21.7% and 73.9%, and 6-month overall response rate and disease control rate were 30.0% and 65.0%. The median survival time from diagnosis of GALM was 31.3 months. The median survival time and median PFS from first DEB-TACE was 21.3 months (95% confidence interval 9.1–33.5) and 10.7 months (3.7–17.7), respectively. Main adverse events included abdominal pain (36.0%), fever (12.0%), and nausea/vomiting (28.0%) after DEB-TACE. No treatment-related deaths and grade 3 or grade 4 adverse events were observed.

Conclusions

DEB-TACE using raltitrexed eluting CB was demonstrated as a safe and efficient alternative choice for GALM.

Dietary folate drives methionine metabolism to promote cancer development by stabilizing MAT IIA

Folic acid, served as dietary supplement, is closely linked to one-carbon metabolism and methionine metabolism. Previous clinical evidence indicated that folic acid supplementation displays dual effect on cancer development, promoting or suppressing tumor formation and progression. However, the underlying mechanism remains to be uncovered. Here, we report that high-folate diet significantly promotes cancer development in mice with hepatocellular carcinoma (HCC) induced by DEN/high-fat diet (HFD), simultaneously with increased expression of methionine adenosyltransferase 2A (gene name, MAT2A; protein name, MATIIα), the key enzyme in methionine metabolism, and acceleration of methionine cycle in cancer tissues. In contrast, folate-free diet reduces MATIIα expression and impedes HFD-induced HCC development. Notably, methionine metabolism is dynamically reprogrammed with valosin-containing protein p97/p47 complex-interacting protein (VCIP135) which functions as a deubiquitylating enzyme to bind and stabilize MATIIα in response to folic acid signal. Consistently, upregulation of MATIIα expression is positively correlated with increased VCIP135 protein level in human HCC tissues compared to adjacent tissues. Furthermore, liver-specific knockout of Mat2a remarkably abolishes the advocating effect of folic acid on HFD-induced HCC, demonstrating that the effect of high or free folate-diet on HFD-induced HCC relies on Mat2a. Moreover, folate and multiple intermediate metabolites in one-carbon metabolism are significantly decreased in vivo and in vitro upon Mat2a deletion. Together, folate promotes the integration of methionine and one-carbon metabolism, contributing to HCC development via hijacking MATIIα metabolic pathway. This study provides insight into folate-promoted cancer development, strongly recommending the tailor-made folate supplement guideline for both sub-healthy populations and patients with cancer expressing high level of MATIIα expression.

Naturally occurring, natural product inspired and synthetic heterocyclic anti-cancer drugs

This chapter describes the importance and activity of a huge number of commercially available naturally occurring, natural product derived or synthetic heterocyclic anti-cancer drugs.

Recent Advances on Quinazoline Derivatives: A Potential Bioactive Scaffold in Medicinal Chemistry

This paper intended to explore and discover recent therapeutic agents in the area of medicinal chemistry for the treatment of various diseases. Heterocyclic compounds represent an important group of biologically active compounds. In the last few years, heterocyclic compounds having quinazoline moiety have drawn immense attention owing to their significant biological activities. A diverse range of molecules having quinazoline moiety are reported to show a broad range of medicinal activities like antifungal, antiviral, antidiabetic, anticancer, anti-inflammatory, antibacterial, antioxidant and other activities. This study accelerates the designing process to generate a greater number of biologically active candidates.

Patient-derived tumor-like cell clusters for drug testing in cancer therapy

Several patient-derived tumor models emerged recently as robust preclinical drug-testing platforms. However, their potential to guide clinical therapy remained unclear. Here, we report a model called patient-derived tumor-like cell clusters (PTCs). PTCs result from the self-assembly and proliferation of primary epithelial, fibroblast, and immune cells, which structurally and functionally recapitulate original tumors. PTCs enabled us to accomplish personalized drug testing within 2 weeks after obtaining the tumor samples. The defined culture conditions and drug concentrations in the PTC model facilitate its clinical application in precision oncology. PTC tests of 59 patients with gastric, colorectal, or breast cancers revealed an overall accuracy of 93% in predicting their clinical outcomes. We implemented PTC to guide chemotherapy selection for a patient with mucinous rectal adenocarcinoma who experienced recurrence with metastases after conventional therapy. After three cycles of a nonconventional therapy identified by the PTC, the patient showed a positive response. These findings need to be validated in larger clinical trials, but they suggest that the PTC model could be prospectively implemented in clinical decision-making for therapy selection.

Risk Factors of Fluoropyrimidine Induced Cardiotoxicity among Cancer Patients: A Systematic Review and Meta-analysis

Cancer patients experienced an increased risk of cardiotoxicity during fluoropyrimidine-based chemotherapy (5-fluorouracil or capecitabine). We searched PubMed, PsycINFO, IPA, CINAHL, Web of Science, and ClinicalTrials.gov for studies published between January 1, 1990 and December 31, 2019, in English, examining risk factors for cardiotoxicity induced by fluoropyrimidine. Included study-level data were converted to risk ratios (RRs) and pooled RRs were calculated for meta-analyses using a random-effects method. Among 690 publications identified for abstract and title screening, 22 unique studies were included in the review, and 20 had sufficient data for meta-analyses. Results indicated that patients undergoing capecitabine-based combination therapy had a higher risk than those with monotherapy (pooled RR = 1.61). Patients with pre-existing cardiac disease (pooled RR = 3.26), hypertension (pooled RR = 1.52) or smoking (pooled RR = 2.22) also had higher risks than their counterparts. Developing risk assessment tools to mitigate the risk could be a viable strategy to improve outcomes for cancer patients undergoing fluoropyrimidine-based treatments.

Clinical efficacy of irinotecan plus raltitrexed chemotherapy in refractory esophageal squamous cell cancer

Our retrospective study assessed the efficacy and safety of irinotecan plus raltitrexed in esophageal squamous cell cancer (ESCC) patients who were previously treated with multiple systemic therapies. Between January 2016 and December 2018, records of 38 ESCC patients who underwent irinotecan plus raltitrexed chemotherapy after at least one line of chemotherapy were reviewed. Efficacy assessment was performed every two cycles according to the RECIST version 1.1. A total of 95 cycles of chemotherapy were administered, and the median course was 3 (range 2-6). There was no treatment-related death. Nine patients had partial response, 21 had stable disease and eight had progressive disease. The overall objective response rate was 23.68% (9/38) and the disease control rate was78.94% (30/38). After a median follow-up of 18.5 months, the median progression-free survival and overall survival were 105 and 221 days, respectively. There were five patients (13.15%) with grade 3/4 leukopenia, three patients (7.89%) with grade 3/4 neutropenia and one patient (2.63%) with grade 3/4 diarrhea. The combination of irinotecan plus raltitrexed was effective for pretreated ESCC patients. Further studies are needed to determine the optimal dose of the two drugs.

Polyphenol from millet bran increases the sensitivity of colorectal cancer cells to oxaliplatin by blocking the ganglioside GM3 catabolism

The study implies that bound polyphenol from millet bran dramatically prevents ganglioside GM3 catabolism followed by the suppression of P-gp, which eventually reverse drug-resistance in colorectal cancer cells to oxaliplatin.

Efficacy And Safety Of Raltitrexed Plus Oxaliplatin-Based Transarterial Chemoembolization In Patients With Unresectable Hepatocellular Carcinoma

Objective

To evaluate the efficacy and safety of raltitrexed plus oxaliplatin-based transarterial chemoembolization (TACE) in patients with unresectable hepatocellular carcinoma (HCC).

Methods

A total of 123 patients with unresectable HCC were recruited into the prospective cohort study. Raltitrexed plus oxaliplatin-based TACE was performed according to the traditional method at monthly intervals and was repeated for up to 4 cycles if no disease progression or intolerable toxicity occurred. The primary efficacy endpoint was overall survival (OS), and the secondary endpoints were progression-free survival (PFS) and tumor response rate. The Cox proportional-hazards regression model was used to assess the independent prognostic factors of OS. Adverse events were also observed.

Results

The median OS time and PFS were 623 days (95% CI: 461, 785) and 338 days (95% CI: 302, 704), respectively. The disease control rate was 95.5% (118/123). The Cox proportional-hazards regression model indicated that age, ECOG performance status and response to TACE as independent prognostic factors of OS. No treatment-related mortality occurred within 30 days of treatment procedure. The most common complications included postembolization syndrome, liver dysfunction and hematological toxicity. Grade 3 pain, transglutaminase abnormality and thrombocytopenia were observed in 16 (13%), 15 (12.2%) and 3 (2.4%) patients, respectively. No grade 4 adverse events were observed.

Conclusion

Raltitrexed plus oxaliplatin-based TACE led to high tumor response rate and promising PFS and OS, and was considered safe and tolerable in patients with unresectable HCC.

CAC1 knockdown reverses drug resistance through the downregulation of P-gp and MRP-1 expression in colorectal cancer

CDK2-associated cullin domain 1 (CAC1) is as a novel cell cycle regulator widely expressed in colorectal cancer (CRC). However, its expression and function in drug resistant CRC cells remains elusive. Therefore, the present study aimed to assess the biochemical function and relevance of CAC1 in drug resistant CRC cells, and detect the potential mechanism. For this purpose, a total of 83 CRC cases were collected for the immunohistochemical analysis of CAC1 expression. Functional studies (stable transfection, flow cytometry, colony formation, and invasion and migration assays) were performed in SW480, LoVo and their corresponding 5-FU resistant cells. In addition, a nude mice xenograft model was established for further observation in vivo. In the present study, CAC1 protein expression was higher in CRC tissues than that in normal tissues (P<0.05). Furthermore, CAC1 protein expression was higher in SW480/5-FU cells than in SW480 cells. CAC1 knockdown arrested 5-FU resistant cells at the G1/S phase and increased the sensitivity of 5-FU resistant cells to 5-FU by inducing apoptosis. In addition, CAC1 reduced the invasive and migration ability of SW480/5-FU and LoVo/5-FU cells in vitro, and reduced their tumorigenicity and metastatic ability in vivo. Finally, CAC1 knockdown resulted in decreased P-glycoprotein and MRP-1 protein expression. Based on these results, it can be concluded that CAC1 plays an important role in the occurrence and promotion of drug resistance in CRC. Therefore, the knockdown of CAC1 may be considered as a new strategy for the development of CRC drug resistance treatments in the future.

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.

Multivalent nanoparticles for personalized theranostics based on tumor receptor distribution behavior

It is acknowledged that the targeting ability of multivalent ligand-modified nanoparticles (MLNs) strongly depends on the ligand spatial presentation determined by ligand valency. However, the receptor overexpression level varies between different types or stages of tumors. Thus, it is essential to explore the influence of ligand valency on the targeting ability of MLNs to tumors with different levels of receptor overexpression. In this study, a dual-acting agent raltitrexed was used as a ligand to target the folate receptor (FR). Different copies of the raltitrexed-modified multivalent dendritic polyethyleneimine ligand cluster PRn (n = 2, 4, and 8) were conjugated onto magnetic nanoparticles to form multivalent magnetic NPs (MMNs) with different valences. The in vitro studies demonstrated that Fe-PR4 was the most effective valency in the treatment of high FR overexpressing KB cells with a decentralized receptor distribution, owing to the fact that Fe-PR2 was negative in statistical rebinding and Fe-PR8 could induce steric hindrance in the limited binding area. Instead, in moderate FR overexpressing HeLa cells with clustered receptor display, the extra ligands on Fe-PR8 would facilitate statistical rebinding more beneficially. Furthermore, in in vivo tumor inhibition and targeted magnetic resonance imaging (MRI) of KB tumors and another moderate FR expressing H22 tumor, similar results were obtained with the cell experiments. Overall, the optimizable treatment effect of Fe-PRn by modulating the ligand valency based on the overexpressing tumor receptor distribution behavior supports the potential of Fe-PRn as a nanomedicine for personalized theranostics.

Efficacy and safety of raltitrexed-based transarterial chemoembolization for colorectal cancer liver metastases

The liver is the most common site of colorectal cancer metastases. The present study aimed to evaluate the efficacy and safety of transarterial chemoembolization (TACE) with raltitrexed and oxaliplatin for colorectal liver metastases in a prospective, multicenter, single-arm trial conducted in 12 hospitals from different areas in China. A total of 90 patients with colorectal liver metastases were enrolled and treated by TACE with raltitrexed 4 mg and oxaliplatin 100 mg, followed by embolotherapy with 50 mg oxaliplatin and 5-20 ml lipiodol, administered every 28 days for four cycles. Patients were followed up every 3 months after the treatment and up to 12 months. The primary endpoint was time to progression. For the full analysis set (FAS), the median time to progression and overall survival were 9.1 and 17.8 months, respectively. The disease control rate in FAS was 71 (78.9%). Grade 3 or 4 adverse events were reported for 24 (26.7%) out of all 90 patients. Grade 3 thrombocytopenia, transglutaminase abnormality, and decreased neutrophil were observed in eight (8.9%), six (6.7%), and five (5.6%) patients, respectively. No unexpected adverse events or toxic deaths were observed. TACE with raltitrexed plus oxaliplatin is feasible, clinically beneficial, and well tolerated with low-grade toxicity for colorectal cancer patients with liver metastases.

Transarterial chemoembolization with raltitrexed-based or floxuridine-based chemotherapy for unresectable colorectal cancer liver metastasis

PURPOSE

To evaluate and compare the efficiency and safety of raltitrexed- or floxuridine (FUDR)-based transarterial chemoembolization (TACE) in patients with unresectable colorectal cancer liver metastasis (CRCLM).

METHODS

We conducted a retrospective analysis of 81 patients with unresectable CRCLM who failed systemic chemotherapy and were treated with TACE in our department from Oct 2014 to Oct 2017. Of these, 61 patients received TACE using raltitrexed, oxaliplatin, and pirarubicin (raltitrexed group), and 20 received TACE using FUDR, oxaliplatin, and pirarubicin (FUDR group). The objective response rate (ORR), disease control rate (DCR), overall survival (OS, from the first TACE), progression-free survival (PFS, from the first TACE), and adverse reactions were evaluated and compared between the two groups, and prognostic factors for OS were analyzed.

RESULTS

The ORRs of the raltitrexed group and FUDR group were 67.2 and 45.0%, respectively (P = 0.076), and the DCRs were 86.9 and 80.0%, respectively (P = 0.452). The median OS (from first TACE) was 14.0 months in the raltitrexed group and 13.0 months in the FUDR group (P = 0.556). The median PFS (from first TACE) was 2.1 months in the raltitrexed group and 2.4 months in the FUDR group (P = 0.878). Univariate and multivariate analyses showed that the primary tumor site, Child-Pugh class, and combination with local ablation (RFA or CRA) were independent significant factors affecting survival. There were no significant differences in adverse reactions between the two groups (P > 0.05), and no treatment-related death occurred in either group.

CONCLUSION

TACE treatment based on raltitrexed or FUDR is an efficient and safe alternative choice for treating unresectable CRCLM.

Molecular docking to Toxoplasma gondii thymidylate synthase-dihydrofolate reductase and efficacy of raltitrexed in infected mice

Toxoplasmosis is a zoonosis of worldwide distribution. Currently, two drugs, pyrimethamine and sulfadiazine, are used as a reference in the treatment of toxoplasmosis, but the resistance of Toxoplasma gondii appears as a relevant public health problem. In order to identify new drugs to toxoplasmosis treatment, we performed a molecular docking of raltitrexed to T. gondii thymidylate synthase-dihydrofolate reductase (TS-DHFR) and also evaluated its efficacy in infected mice. Initially, raltitrexed was docked on the crystallographic structures of TS-DHFR from T. gondii and Mus musculus. Then, 48 h after infection with the T. gondii RH strain, different groups of mice received an oral dose of raltitrexed (0.15, 0.75, and 1.5 mg kg^-1). Two days after treatments, raltitrexed was able to prevent mortality and reduce the number of tachyzoites in the peritoneal fluid and liver imprints from infected mice. The results showed that raltitrexed has important protective activities against the T. gondii RH strain. Molecular docking still suggests that the effects against the parasite may be dependent on the inhibition of T. gondii thymidylate synthase. This study opens new perspectives for the use of raltitrexed in patients infected with T. gondii, especially when conventional treatments do not exhibit the expected efficacy.

Network meta-analysis of the efficacy of first-line chemotherapy regimens in patients with advanced colorectal cancer

This network meta-analysis compared the short-term and long-term efficacies of first-line chemotherapy regimens in patients with advanced colorectal cancer (CRC). The 10 regimens included folinic acid + 5-fluorouracil + oxaliplatin (FOLFOX), folinic acid + 5-fluorouracil + irinotecan (FOLFIRI), folinic acid + 5-fluorouracil + gemcitabine (FFG), folinic acid + 5-fluorouracil + trimetrexate (FFT), folinic acid + 5-fluorouracil (FF), irinotecan + oxaliplatin (IROX), raltitrexed + oxaliplatin (TOMOX), folinic acid + tegafur-uracil (FTU), raltitrexed, and capecitabine. Electronic searches were performed in the Cochrane Library, PubMed and Embase databases from inception to June 2017. Network meta-analysis combined direct and indirect evidence to obtain odds ratios (ORs) and surface under the cumulative ranking curves (SUCRA) of different chemotherapy regimens for advanced CRC. Fourteen randomized controlled trails (RCTs) covering 4,383 patients with advanced CRC were included. The results revealed that FOLFOX, FOLFIRI, IROX, and TOMOX all showed higher overall response rates (ORRs) than FF or raltitrexed. Compared with raltitrexed, the aforementioned four regimens also had higher 1-year progression-free survival (PFS) rates. In addition, FOLFOX and FOLFIRI exhibited higher disease control rates (DCRs) and 1-year PFS rates than FF or raltitrexed. Cluster analysis revealed that FOLFOX, FOLFIRI, and TOMOX had better short-term and long-term efficacies. These findings suggest FOLFOX, FOLFIRI, and TOMOX are superior to other regimens for advanced CRC. These three regimens are therefore recommended for clinical treatment of advanced CRC.

Comparison of two transarterial chemoembolization regimens in patients with unresectable hepatocellular carcinoma: raltitrexed plus oxaliplatin versus 5-fluorouracil plus oxaliplatin

AIMS

To compare the safety and efficacy of TACE using raltitrexed, oxaliplatin and epirubicin with 5-fluorouracil, oxaliplatin and epirubicin for patients with unresectable hepatocelluar carcinoma.

RESULTS

Median overall survival (OS) was 7.4 months in the raltitrexed group [95% confidence interval (CI): 5.4, 9.4) and 5.8 months in the control group (95% CI: 5.2, 6.4; P = 0.177). The median progression-free survival (PFS) time was significantly higher in the raltitrexed group (3.6 months, 95% CI: 2.8, 4.4) than in the control group (2.6 months, 95% CI: 2.2, 3.0; P = 0.038). The disease control rate (DCR) was higher in the raltitrexed group than in the control group (40% versus 30.4%; P = 0.353). The incidence of adverse events was similar between the two groups.

MATERIALS AND METHODS

From January 2012 to December 2014, 86 patients with unresectable HCC were treated with TACE using the combination of raltitrexed, oxaliplatin and epirubicin (raltitrexed group), and the combination of 5-fluorouracil, oxaliplatin and epirubicin (control group). The primary endpoint was OS, and the secondary endpoints were PFS, DCR and adverse events.

CONCLUSIONS

Although the study did not meet its primary endpoint, raltitrexed group reach a higher PFS, which suggests that this combination regimen of TACE as alternative may confer some benefits to selected patients.

Raltitrexed Inhibits HepG2 Cell Proliferation via G0/G1 Cell Cycle Arrest

Raltitrexed (RTX) is an antimetabolite drug used as a chemotherapeutic agent for treating colorectal cancer, malignant mesothelioma, and gastric cancer. The antitumor capacity of RTX is attributed to its inhibitory activity on thymidylate synthase (TS), a key enzyme in the synthesis of DNA precursors. The current study is aimed at investigating the potential antitumor effects of RTX in liver cancer. Using the HepG2 cell line as an in vitro model of liver cancer, we evaluated the effects of RTX on cell proliferation employing both a WST-8 assay and a clone formation efficiency assay. In addition, we monitored the ultrastructure changes of HepG2 cells in response to RTX with transmission electric microscopy. To investigate the mechanism underlying the regulation of cell proliferation by RTX, we analyzed cell cycle using cell flow cytometry. Moreover, real-time PCR and Western blot analyses were conducted to examine expression levels of cell cycle regulatory proteins cyclin A and cyclin-dependent kinase 2 (CDK2), as well as their mediators tumor suppressor genes p53 and p16. Our results demonstrate that RTX inhibits HepG2 proliferation by arresting the cell cycle at G₀/G₁. This cell cycle arrest function was mediated via downregulation of cyclin A and CDK2. The observed elevated expression of p53 and p16 by RTX may contribute to the reduction of cyclin A/CDK2. Our study indicates that RTX could serve as a potential chemotherapeutic agent in the treatment of hepatocellular carcinoma.

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.