Sophoridinol derivative 05D induces tumor cells apoptosis by topoisomerase1-mediated DNA breakage

The biological activities of quinolizidine alkaloids

Quinolizidine alkaloids isolated from various marine and terrestrial animals and plants are primarily composed of lupinine-, matrine-, and sparteine-type alkaloids. Matrine, phenanthroquinolizidines, bis-quinolizidines, and small molecules from amphibian skins are representative compounds of such alkaloids. Quinolizidine alkaloids harbor anticancer, antibacterial, antiinflammatory, antifibrosis, antiviral, and anti-arrhythmia. In this chapter, we comprehensively outline the biological activity and pharmacological action of quinolizidine alkaloids and discuss new avenues toward the discovery of novel and more efficient drugs based on these naturally occurring compounds. It is urgent for basic research and clinical practice to conduct more targeted comprehensive research based on the lead drugs of quinolizidine alkaloids with significant pharmacological activity.

Research Progress in the Pharmacological Activities, Toxicities, and Pharmacokinetics of Sophoridine and Its Derivatives

Sophoridine is a natural quinolizidine alkaloid and a bioactive ingredient that can be isolated and identified from certain herbs, including Sophora flavescens Alt, Sophora alopecuroides L, and Sophora viciifolia Hance. In recent years, this quinolizidine alkaloid has gained widespread attention because of its unique structure and minimal side effects. Modern pharmacological investigations have uncovered sophoridine's multiple wide range biological activities, such as anti-cancer, anti-inflammatory, anti-viral, anti-arrhythmia, and analgesic functions, among others. These pharmacological activities and beneficial effects point to sophoridine as a strong potential therapeutic candidate for the treatment of various diseases, including several cancer types, hepatitis B virus, enterovirus 71, coxsackievirus B3, cerebral edema, cancer pain, heart failure, acute myocardial ischemia, arrhythmia, inflammation, acute lung injury, and osteoporosis. The data showed that sophoridine had adverse reactions, including hepatotoxicity and neurotoxicity. Additionally, analyses of sophoridine's safety, bioavailability, and pharmacokinetic parameters in animal models of research have been limited, especially in the clinic, as have been investigations on its structure-activity relationship. In this article, we comprehensively summarize the biological activities, toxicity, and pharmacokinetic characteristics of sophoridine and its derivatives, as currently reported in publications, as we attempt to provide an overall perspective on sophoridine analogs and the prospects of its application clinically.

The novel quinolizidine derivate IMB-HDC inhibits STAT5a phosphorylation at 694 and 780 and promotes DNA breakage and cell apoptosis via blocking STAT5a nuclear translocation

Sophoridine is a quinolizidine natural product and the exploration of its derivatives has been carried out, and the potent anticancer compound IMB-HDC was acquired. Although previous studies have revealed that some sophoridine derivatives could induce DNA breakage, the underlying mechanisms of inhibition of DNA damage repair (ATR inactivation) and the apoptosis independent of p53, have not been elucidated. Our research reveals a novel DNA response mechanism different from general DNA-damaging agents, and that sophoridine derivate inhibits the phosphorylation of Tyr694 and Ser780 of STAT5a to induce the lessened shuttle from the cytoplasm to the nucleus, and leads to the decreased nuclear STAT5a and subsequently inhibits the expression of STAT5a target gene RAD51 that contributes to the checkpoint activation, thus inhibiting ATR activation. Meanwhile, IMB-HDC that induced the diminished expression of STAT5a target gene contributes to proliferation and leads to apoptosis. More importantly, we give the first evidence that promoting the effect of Tyr694 phosphorylation on nuclear location and subsequent STAT5a target gene transcription depends on Ser780 increased or unchanged phosphorylation and was not correlated with Ser726 phosphorylation.

Anti-cancer potential of sophoridine and its derivatives: Recent progress and future perspectives

Cancer is the second leading cause of mortality and has resulted in about 9.6 million deaths around the world in 2018. Cancer-caused deaths are expected to be 11.5 million by 2030 all over the world. Because of the fatal nature of cancer, substantial efforts are made all over the world to combat it. Phytoconstituents such as certain alkaloids, saponins, tannins, polyphenols, and terpenoids exhibit anticancer effects. Sophoridine is a tetracyclic quinolizidine alkaloid isolated from the stem and leaves of medicinal plants Sophora alopecuroides L., and Euchresta japonica Benth, and roots of Sophora alopecuroides Ait. Chinese Food and Drug Administration (CFDA) approved sophoridine as an antitumor agent in 2005. This review covers the antitumor activities of sophoridine and its derivatives. The efficacy of sophoridine analogs is expressed with respect to their half-maximal inhibitory concentration (IC₅₀ values). Structure-activity relationship (SAR) study for most of the sophoridine derivatives has been explained. Moreover, the current market of anticancer drugs and its expected growth are discussed. Prospects provide suggestions and clues for novel sophoridine-based anticancer agents with enhanced expected efficacy and minimum toxicity.

Sophoridine inhibits lung cancer cell growth and enhances cisplatin sensitivity through activation of the p53 and Hippo signaling pathways

BACKGROUND

Sophoridine, a quinolizidine alkaloid extracted from the Chinese herb Sophora alopecuroides L., has been reported to exert antitumor effects against multiple human cancers. However, few studies have evaluated its tumor-suppressing effects and associated mechanism with respect to lung cancer, in addition to its potential to be used for clinical lung cancer treatment.

METHODS

Different types of lung cancer cells were used to investigate the antitumor effects of sophoridine using cell viability, colony formation, and cell invasion, and migration assays. To determine the signaling pathways involved, western blot analysis, quantitative real-time polymerase chain reaction, an in vivo ubiquitination assay, and immunohistochemistry were used in cellular assays and with a subcutaneous xenograft model in BALB/c mice.

RESULTS

Sophoridine significantly suppressed the proliferation of and colony formation by lung cancer cells in vitro. Transwell assays demonstrated that sophoridine also inhibited invasion and migration in lung cancer cells. In addition, sophoridine enhanced the effects of cisplatin on lung cancer cells. A mechanistic study revealed that sophoridine significantly activated the Hippo and p53 signaling pathways, and mouse xenograft experiments further confirmed in vitro findings in lung cancer cells.

CONCLUSIONS

Taken together, these results suggest that sophoridine can inhibit lung cancer progression and enhance the effects of the anticancer drug cisplatin against lung cancer cells. The mechanism of action of sophoridine might involve the Hippo and p53 signaling pathways.

Design, synthesis, biological evaluation and structure-activity relationship of sophoridine derivatives bearing pyrrole or indole scaffold as potential antitumor agents

Taking sophoridine as a lead compound, 58 sophoridine derivatives were designed, synthesized and evaluated for their antiproliferative activity in the HepG2 cancer cell line. Among the 58 compounds, 33 compounds showed potent antiproliferative activity with IC₅₀ less than 10 μM. Compound 5w showed the most potent anti-proliferative activity in the HepG2 cancer cell line. Thus, we further extended our characterization of the antiproliferative activity of 5w in six cancer cell lines (HepG2, SMMC-7721, Hela, CNE1, CNE2 and MCF7). The representative compound 5w displayed robust anti-proliferative activities in all the tested cell lines with IC₅₀ values in range of 0.93-1.89 μM which were much lower than that of sophoridine. Here, we report the structure-activity relationships (SAR) in a sophoridine series of compounds, which indicated that introduction of N-benzyl indole group on the 14-carbon atom of sophoridine can significantly enhance the antiproliferative activity. By molecular docking and enzymatic assay, compound 5w was found to be able to inhibit the activity of DNA Topo I. Furthermore, apoptosis assay displayed that compound 5w could significantly induce the apoptosis of HepG2 cells in a dose-dependent manner by activating caspase-3, increasing expression of cleaved caspase-3 and reducing the ratio of Bcl-2/Bax. The in vivo antitumor assay demonstrated that 5w suppressed the growth of HepG2 xenografts in nude mice without any obvious side effects.

Cyclizing-berberine A35 induces G2/M arrest and apoptosis by activating YAP phosphorylation (Ser127)

BACKGROUND

A35 is a novel synthetic cyclizing-berberine recently patented as an antitumor compound. Based on its dual targeting topoisomerase (top) activity, A35 might overcome the resistance of single-target top inhibitors and has no cardiac toxicity for not targeting top2β. In this study we further explored the biological effects and mechanisms of A35.

METHODS

Antitumor activity of A35 was evaluated by SRB and colony formation assay. G2/M phase arrest (especially M) and first damage of M-phase cells were investigated by flow cytometry, cytogenetic analysis, immunofluorescence, co-immunoprecipitation and WB. The key role of phospho-YAP (Ser127) in decreasing YAP nuclear localization, subsequent G2/M arrest and proliferation inhibition were explored by YAP1^-/- cells, mutated Ser127 YAP construct (Ser127A) and TUNEL.

RESULTS

G2/M arrest induced by A35 was independent of p53. M phase cells at low dose were firstly damaged and most damaged-cells accumulated in M phase, and that was a result of preferring targeting top2α by A35, as top2α is essential to push M phase into next phase, and targeting top2α induced cells arrested at M phase. A35 decreased YAP1 nuclear localization by activating YAP phosphorylation (Ser127) which subsequently regulated the transcription of YAP target genes associated with growth and cycle regulation to induce G2/M arrest and growth inhibition.

CONCLUSIONS

Our studies suggested the mechanism of G2/M arrest induced by A35 and a novel role of YAP1 (Ser127) in G2/M arrest. As a dual topoisomerase inhibitor characterized by no cardiac toxicity, A35 is a promising topoisomerase anticancer agent and worthy of further development in future.