A novel topoisomerase I inhibitor DIA-001 induces DNA damage mediated cell cycle arrest and apoptosis in cancer cell

Narciclasine, a novel topoisomerase I inhibitor, exhibited potent anti-cancer activity against cancer cells

DNA topoisomerases are essential nuclear enzymes in correcting topological DNA errors and maintaining DNA integrity. Topoisomerase inhibitors are a significant class of cancer chemotherapeutics with a definite curative effect. Natural products are a rich source of lead compounds for drug discovery, including anti-tumor drugs. In this study, we found that narciclasine (NCS), an amaryllidaceae alkaloid, is a novel inhibitor of topoisomerase I (topo I). Our data demonstrated that NCS inhibited topo I activity and reversed its unwinding effect on p-HOT DNA substrate. However, it had no obvious effect on topo II activity. The molecular mechanism of NCS inhibited topo I showed that NCS did not stabilize topo-DNA covalent complexes in cells, indicating that NCS is not a topo I poison. A blind docking result showed that NCS could bind to topo I, suggesting that NCS might be a topo I suppressor. Additionally, NCS exhibited a potent anti-proliferation effect in various cancer cells. NCS arrested the cell cycle at G2/M phase and induced cell apoptosis. Our study reveals the antitumor mechanisms of NCS and provides a good foundation for the development of anti-cancer drugs based on topo I inhibition.

Transcriptomics and Proteomics Characterizing the Anticancer Mechanisms of Natural Rebeccamycin Analog Loonamycin in Breast Cancer Cells

The present study is to explore the anticancer effect of loonamycin (LM) in vitro and in vivo, and investigate the underlying mechanism with combined multi-omics. LM exhibited anticancer activity in human triple negative breast cancer cells by promoting cell apoptosis. LM administration inhibited the growth of MDA-MB-468 tumors in a murine xenograft model of breast cancer. Mechanistic studies suggested that LM could inhibit the topoisomerase I in a dose-dependent manner in vitro experiments. Combined with the transcriptomics and proteomic analysis, LM has a significant effect on O-glycan, p53-related signal pathway and EGFR/PI3K/AKT/mTOR signal pathway in enrichment of the KEGG pathway. The GSEA data also suggests that the TNBC cells treated with LM may be regulated by p53, O-glycan and EGFR/PI3K/AKT/mTOR signaling pathway. Taken together, our findings predicted that LM may target p53 and EGFR/PI3K/AKT/mTOR signaling pathway, inhibiting topoisomerase to exhibit its anticancer effect.

A novel irinotecan derivative ZBH-1207 with different anti-tumor mechanism from CPT-11 against colon cancer cells

PURPOSE

Irinotecan (CPT-11) is a camptothecin derivative whose potent anti-tumor activity depends on the rapid formation of an in vivo active metabolite, SN38 (7-ethyl-10-hydroxycamptothecin). CPT-11 combine with other agents are often the treatment of choice for patients with advanced or metastatic colorectal cancer (CRC). This study evaluates the cytotoxic mechanism of a novel CPT-11 derivative, ZBH-1207 in CRC cells in vitro.

METHODS

The anti-proliferation effect of ZBH-1207 on tumor cells was assessed by MTT assay. The inhibition of TOP1, the alteration of cell cycle and apoptosis, and the expression of caspase-3 and PARP in CRC cells induced by ZBH-1207 were detected by DNA relaxation assay, flow cytometry, and Western blot, respectively.

RESULTS

ZBH-1207 significantly inhibits the proliferation of seven tumor cell lines and retains the activity of TOP1 as compared with CPT-11. Treatment with ZBH-1207 results in more apparent cell cycle arrests and apoptosis of CRC cells than that of CPT-11 and SN38. Accordingly, up-regulation of active caspase-3 and PARP expression were relatively higher in ZBH-1207 group than that in CPT-11 and SN38 group.

CONCLUSION

ZBH-1207 has higher cytotoxicity than CPT-11/SN38 in CRC cells. Its molecular mechanism involves apoptosis signaling pathway.

A patent review of topoisomerase I inhibitors (2016-present)

INTRODUCTION

Topoisomerases are important targets for therapeutic improvement in the treatment of some diseases, including cancer. Inhibitors and poisons of topoisomerase I can limit the activity of this enzyme in its enzymatic cycle. This fact implies an anticancer effect of these drugs, since most cancer cells are characterized by both a higher activity of topoisomerase I and a higher replication rate compared to non-cancerous cells. Clinically approved inhibitors include camptothecin (CPT) and its derivatives. However, their limitations have encouraged different research groups to prepare new compounds, proof of which are the numerous research works and patents, some of them in the last five years.

AREAS COVERED

This review covers patent literature on topoisomerase I inhibitors and their application published between 2016-present.

EXPERT OPINION

The highest contribution toward patent development has been obtained from academics or small biotechnology companies. The most important fields of innovation include the preparation of prodrugs or inhibitors combined with other agents, as biocompatible polymers or antibodies. A promising development of topoisomerase I inhibitors is expected in the next years, directed to the treatment of diverse diseases, specifically toward different types of cancer and infectious diseases, among others.

Recent advances and future directions in anti-tumor activity of cryptotanshinone: A mechanistic review

In respect to the enhanced incidence rate of cancer worldwide, studies have focused on cancer therapy using novel strategies. Chemotherapy is a common strategy in cancer therapy, but its adverse effects and chemoresistance have limited its efficacy. So, attempts have been directed towards minimally invasive cancer therapy using plant derived-natural compounds. Cryptotanshinone (CT) is a component of salvia miltiorrihiza Bunge, well-known as Danshen and has a variety of therapeutic and biological activities such as antioxidant, anti-inflammatory, anti-diabetic and neuroprotective. Recently, studies have focused on anti-tumor activity of CT against different cancers. Notably, this herbal compound is efficient in cancer therapy by targeting various molecular signaling pathways. In the present review, we mechanistically describe the anti-tumor activity of CT with an emphasis on molecular signaling pathways. Then, we evaluate the potential of CT in cancer immunotherapy and enhancing the efficacy of chemotherapy by sensitizing cancer cells into anti-tumor activity of chemotherapeutic agents, and elevating accumulation of anti-tumor drugs in cancer cells. Finally, we mention strategies to enhance the anti-tumor activity of CT, for instance, using nanoparticles to provide targeted drug delivery.