Epirubicin, Cisplatin, and Raltitrexed in Patients With Advanced Gastric and Hepatobiliary Carcinoma

Raltitrexed regulates proliferation and apoptosis of HGC-27 cells by upregulating RSK4

Background

Raltitrexed is a specific inhibitor of thymidylate synthase and a potential chemotherapeutic agent for the treatment of advanced gastric cancer. In this study, we investigated the effect of raltitrexed on the proliferation of HGC-27 human gastric cancer cells and its potential underlying molecular mechanism(s).

Methods

RT-qPCR and western blotting were used to quantify RSK4 levels. Colony formation and flow cytometry assays were used to assess HGC-27 cell proliferation, cell cycle progression, mitochondrial membrane potential, and apoptosis. The expression of cell cycle and apoptosis markers were determined by western blotting.

Results

Our results demonstrate that raltitrexed upregulated RSK4 mRNA and protein levels in HGC-27 cells. Moreover, raltitrexed significantly inhibited tumor cell colony formation, arrested the cell cycle, decreased the mitochondrial membrane potential, and induced apoptosis. We observed that raltitrexed was capable of upregulating the expression of Bax, cyclin A1, and CDK3, and downregulating the expression of Bcl-2 and cleaved caspase-3. Importantly, siRNA-mediated RSK4 knockdown significantly reduced the inhibitory effect of raltitrexed on cell proliferation and its promotion of cell apoptosis. Moreover, silencing of RSK4 inhibited the raltitrexed-induced upregulation of cytochrome C. In addition, the changes in molecular markers related to the cell cycle and apoptosis induced by raltitrexed were reduced upon RSK4 depletion.

Conclusion

Our study shows that RSK4 is a key target of raltitrexed in the regulation of gastric cancer cell proliferation, cell cycle progression, and apoptosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-022-00605-2.

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.

Preliminary investigation of intraperitoneal raltitrexed in patients with gastric cancer

Background

Peritoneal implantation metastasis of gastric cancer is the major reason for cancer recurrence after radical operations. As a new chemotherapeutic agent, raltitrexed has been widely used in intravenous chemotherapy for many kinds of cancers. However, no study has reported the efficacy and safety of raltitrexed in intraperitoneal chemotherapy. This study aimed to explore the safety of intraperitoneal chemotherapy with raltitrexed during gastric cancer operation compared to normal saline (NS) rinsing of the abdominal cavity.

Methods

In this prospective study, 91 gastric cancer patients undergoing surgery and reconstruction were consecutively enrolled and randomly assigned into two groups. Raltitrexed in NS (500 ml) was injected into the abdominopelvic cavity for the patients in the RT group (n = 48), while for the patients in the group NS (n = 43), only NS (500 ml) was injected. The postoperative complications, gas passage time, and adverse effects, according to NCI-CTCAE v3.0, were compared between the two groups.

Results

There were no significant differences in age, sex, cancer pathological type, clinical stage or operation method between the two groups (all P >0.05). No significant difference was observed in adverse effects and postoperative complications between the two groups (all P >0.05). No significant change was found in the levels of red blood cells, white blood cells, platelets, lactate dehydrogenase, blood urea nitrogen, and alanine aminotransferase before and after the operation for both groups (all P >0.05). All adverse events were mild or moderate by NCI-CTCAE v3.0 (National Cancer Institute common terminology criteria for adverse events) grade.

Conclusions

The findings of the present study demonstrate that intraperitoneal chemotherapy with raltitrexed after gastric cancer operation is safe and could be used for patients.

Raltitrexed-based chemotherapy for advanced colorectal cancer

AIMS

To evaluate the efficiency and safety profile of raltitrexed-based chemotherapy in the treatment of advanced colorectal cancer.

METHODS

An electronic search was undertaken to identify randomized controlled trials comparing raltitrexed-based regimen to 5-fluorouracil-based regimen in patients with advanced colorectal cancer. The outcomes included overall survival, overall response rate and toxicities.

RESULTS

This meta-analysis included 11 studies with 4622 patients. Overall, there were no significant differences between the two regimens in terms of overall survival (HR=1.06, 95% CI: 0.96-1.17, P=0.23) or overall response rate (RR=1.09, 95% CI: 0.86-1.38, P=0.47). In subgroup analysis, patients in raltitrexed/oxaliplatin group had significantly higher partial response (RR=1.53, 95% CI: 1.17-2.00, P=0.002), overall response rate (RR=1.42, 95% CI: 1.10-1.82, P=0.006), disease control rate (RR=1.16, 95% CI: 1.04-1.29, P=0.009) and lower progressive disease (RR=0.61, 95% CI: 0.45-0.84, P=0.002) when compared to 5-fluorouracil/leucovorin/oxaliplatin group. Occurrence of severe anemia (RR=2.23, 95% CI: 1.38-3.59, P=0.0001), asthenia (RR=2.29, 95% CI: 1.36-3.84, P=0.002), hepatic disorders (RR=7.51, 95% CI: 1.30-43.56, P=0.02), and nausea/vomit (RR=1.70, 95% CI: 1.03-2.81, P=0.04) were significantly higher with the raltitrexed arm treatment, while frequencies of grade 3/4 alopecia (RR=0.36, 95% CI: 0.26-0.50, P<0.00001) and stomatitis/mucositis (RR=0.14, 95% CI: 0.07-0.31, P<0.00001) were increased in the 5-fluorouracil group.

CONCLUSIONS

Raltitrexed-based chemotherapy regimen leads to an equivalent overall survival and response rates with acceptable toxicities compared to traditional 5-fluorouracil-based regimen in patients with advanced colorectal cancer. Raltitrexed can be a treatment option for these patients when 5-fluorouracil-based regimens are not tolerated or inappropriate.