Biomolecular study of human thymidylate synthase conformer-selective inhibitors: New chemotherapeutic approach

Acetaminophen-traces bioremediation with novel phenotypically and genotypically characterized 2 Streptomyces strains using chemo-informatics, in vivo, and in vitro experiments for cytotoxicity and biological activity

We isolated two novel bacterial strains, active against the environmental pollutant acetaminophen/Paracetamol®. Streptomyces chrestomyceticus (symbol RS2) and Flavofuscus (symbol M33) collected from El-Natrun Valley, Egypt-water, sediment, and sand samples, taxonomically characterized using a transmission electron microscope (TEM). Genotypic identification, based on 16S rRNA gene sequence analysis followed by BLAST alignment, were deposited on the NCBI as 2 novel strains https://www.ncbi.nlm.nih.gov/nuccore/OM665324  and https://www.ncbi.nlm.nih.gov/nuccore/OM665325 . The phylogenetic tree was constructed. Acetaminophen secondary or intermediate product's chemical structure was identified by GC/LC MS. Some selected acetaminophen secondary-product extracts and derived compounds were examined against a panel of test micro-organisms and fortunately showed a good anti-microbial effect. In silico chemo-informatics Swiss ADMET evaluation was used in the selected bio-degradation extracts for absorption (gastric), distribution (to CNS), metabolism (hepatic), excretion (renal), and finally not toxic, being non-mutagenic/teratogenic or genotoxic, virtually. Moreover, in vitro cytotoxic activity of these selected bio-degradation secondary products was examined against HepG2 and MCF7 cancer cell lines, where M33 and RS2 extract effects on acetaminophen/paracetamol bio-degradation products were safe, with higher IC50 on HepG2 and MCF7 than the acetaminophen/paracetamol IC50 of 108.5 μg/ml. Moreover, an in vivo oral acute single-dose toxicity experiment was conducted, to confirm these in vitro and in silico lower toxicity (better safety) than acetaminophen/paracetamol.

Ensemble-based virtual screening of African natural products to target human thymidylate synthase

Human thymidylate synthase (hTS) is a validated drug target for chemotherapy. A virtual screening experiment was used to prioritize a list of compounds from African Natural Products Databases docked against the orthosteric binding pocket of hTS. Consensus scores of binding affinities from ensemble-based virtual screening, hydrated docking and MM-PBSA calculations ranked compounds NEA4433 and NEA4434 as the best candidates owing to binding affinity scores in the picomolar order, their excellent ADMET profiles and the good stability of the protein-ligand complexes formed. The current study demonstrates the role of water in small molecule binding to hTS in mediating protein-ligand interactions. Similarly, the robust ensemble docking (relaxed scheme complex) ranked NEA4433 and NEA4434 as the best candidates. Furthermore, the best candidates prioritized were shown to strongly interact with the same residues that interacted with hTS substrate and cofactor.

Comparing effectiveness and safety of paclitaxel plus raltitrexed vs. paclitaxel alone in second-line palliative chemotherapy for metastatic gastric adenocarcinoma: A randomized phase II clinical trial

OBJECTIVE

Paclitaxel (P) is a standard second-line chemotherapy in the treatment of advanced gastric cancer. This study compared the clinical outcome of a paclitaxel plus raltitrexed (RP) regimen as second-line treatment in metastatic gastric cancer (MGC) patients.

METHODS

An open, randomized, multi-center phase II clinical trial was conducted involving 148 patients who were randomly assigned and treated with RP [raltitrexed (3 mg/m2 on day 1) and paclitaxel (135 mg/m2 on day 1 every 3 weeks)] or P [paclitaxel (135 mg/m2 on day 1 every 3 weeks)] as 2nd-line chemotherapy. The primary endpoint was progression-free survival (PFS). The secondary endpoints were the overall response rate (ORR), overall survival (OS), and safety.

RESULTS

PFS had a tendency to be prolonged with RP compared to P (2.7 months vs. 1.7 months; P = 0.148). OS was also prolonged with RP compared to P (10.2 months vs. 6.1 months; P = 0.140). The ORR was equal in the RP and P groups (6.8% and 4.0%; P = 0.72). The disease control rate (DCR) in the RP and P groups was 56.2% and 36.0%, respectively. Grade 3-4 treatment-related adverse events occurred in 36.2% (RP) and 28.2% (P) of patients. Frequent grade 3-4 toxicities for RP and P were neutropenia (11.0% and 4.0%), anemia (1.4% and 4.0%), and thrombocytopenia (1.4% and 5.3%), and all grades of peripheral neurotoxicity (12.3% vs. 17.3%). All grades of hepatic toxicity were demonstrated for the RP and P groups based on elevated aminotransferase levels (27.4% and 14.1%). Subgroup analysis shows if MGC was combined with ascites or peritoneal involvement, the OS of the RP regimen was longer (P = 0.05).

CONCLUSIONS

Second-line palliative chemotherapy with RP was shown to prolong the PFS and OS, especially among patients with ascites or peritoneal involvement, which warrants confirmation using larger sample studies.

Efficacy and safety of raltitrexed-based transcatheter arterial chemoembolization for intermediate and advanced hepatocellular carcinoma: A multicenter real-world study

AIM

This study aimed to evaluate efficacy and safety of raltitrexed-based transcatheter arterial chemoembolization (TACE) for intermediate and advanced hepatocellular carcinoma (HCC) using real-world evidence.

METHODS

All eligible HCC cases were collected from multiple centers in Chongqing, China, from January 2013 to December 2018 and divided into the raltitrexed group (raltitrexed + lobaplatin + pirarubicin) and control group (lobaplatin + pirarubicin). Propensity score matching (PSM) with a 1:1 ratio was used to eliminate the imbalance of potential confounding factors between groups. The primary end-point was overall survival (OS) and the secondary end-points were progression-free survival (PFS) and disease control rate.

RESULTS

The median follow-up period for patients in the raltitrexed and control groups was 8.7 and 5.9 months, respectively. After PSM, median OS was 10.0 months in the raltitrexed group and 7.0 months in the control group (p = 0.002). The 6-month, 1-year, and 2-year OS rates of the raltitrexed group were significantly higher than those of the control group (78.2% vs. 60.9%, p = 0.010; 43.5% vs. 22.8%, p = 0.030; and 17.4% vs. 2.2% p = 0.001, respectively). Multivariate analysis of these propensity score-matched HCC patients revealed treatment, age, tumor size, lipiodol accumulation, and the number of TACE cycles as independent predictors of OS (all p < 0.05). The disease control rate of the raltitrexed and control groups was 87.4% and 65.8%, respectively (p < 0.001).

CONCLUSIONS

Raltitrexed-based TACE can prolong the OS of patients with intermediate and advanced HCC in a real-world clinical setting, and is safe and tolerable.

1,3,4-Oxadiazole Containing Compounds As Therapeutic Targets For Cancer Therapy

BACKGROUND

Cancer is the first or second leading cause of premature death in 134 of 183 countries in the world. 1,3,4-Oxadiazoles are five memebered heterocyclic rings containing two nitrogen (two atoms) and oxygen (one atom). They show better thermal stability, metabolic stability, aqueous solubility and lower lipophilicity than the other isomeric oxadiazoles. They are important class of heterocycles present in many drug structures like Raltegravir, Furamizole Tidazosin, Nesapidil, Setileuton (MK-0633) and Zibotentan. Presence of this nucleus in the therapeutics has made them an indispensable anchor for drug design and development. Several 1,3,4-oxadiazoles are prepared and reported as anticancer agents by numerous scientists worldwide.

OBJECTIVES

The present review discusses the anticancer potentials together with the molecular targets of 1,3,4-oxadiazoles reported since 2010. The structure activity relationship (SAR) and molecular docking simulation on different targets have also been discussed herein. Some of the important cancer targets have also been explored.

METHODS

The most potent 1,3,4-oxadiazoles reported in literature was highlighted in the manuscript. The anticancer activity was reported in terms of growth percent (GP), percent growth inhibition (%GI), GI50, IC50, and LC50 and TGI.

RESULTS

1,3,4-Oxadiazoles are an important heterocyclic scaffolds with broad spectrum biological activities. They may be either mono substituted or disubstituted and act as an indispensable anchor for drug design and discovery due to their thermal stability together with low lipophilicity. They exhibited anticancer potentials and showed the inhibitions of various cancer targets.

CONCLUSION

The discussion outlined herein will proved to be a helpful and vital tool for medicinal chemists investigating and working with 1,3,4-oxadiazoles and anticancer research programs.

Comparison of transcatheter arterial chemoembolization with raltitrexed plus liposomal doxorubicin vs. tegafur plus pirarubicin for unresectable hepatocellular carcinoma

Background

There is still no general consensus on the optimal chemotherapeutic agent selection for transcatheter arterial chemoembolization (TACE) in unresectable hepatocellular carcinoma (HCC). The present study aimed to compare the efficacy and safety of TACE with raltitrexed plus liposomal doxorubicin (R + PGLD) vs. tegafur plus pirarubicin (T + P) in patients with unresectable HCC.

Methods

A total of 148 patients with unresectable HCC treated with TACE between January 2012 and December 2016 were retrospectively analyzed. Of them, 74 patients were in the R + PGLD group and 74 patients were in the T + P group (1:1). The treatment response of the tumor, overall survival (OS) time, and adverse effects were compared between the two groups.

Results

There were no significant differences in patient characteristics or embolization effect (lipiodol deposition) between the two groups (P>0.05). R + PGLD treatment had a better clinical efficacy than T + P treatment (OR: 64.9% vs. 45.9%, P=0.031; DC: 89.2% vs. 74.3%, P=0.032). Portal vein invasion, hepatic vein invasion, tumor size and BCLC stage were associated with OR or DC after TACE using R + PGLD treatment. Survival analysis revealed that patients who received TACE with R + PGLD had a better prognosis than those treated with T + P. Moreover, some complications in the R + PGLD group, including vomiting, myelosuppression and cardiotoxicity, were significantly lower than those in the T + P group (P<0.05).

Conclusions

TACE with raltitrexed and liposomal doxorubicin could reduce the incidence of adverse reactions and significantly improve the OS of patients with unresectable HCC.

Anti-Cancer Activity of Derivatives of 1,3,4-Oxadiazole

Compounds containing 1,3,4-oxadiazole ring in their structure are characterised by multidirectional biological activity. Their anti-proliferative effects associated with various mechanisms, such as inhibition of growth factors, enzymes, kinases and others, deserve attention. The activity of these compounds was tested on cell lines of various cancers. In most publications, the most active derivatives of 1,3,4-oxadiazole exceeded the effect of reference drugs, so they may become the main new anti-cancer drugs in the future.