Binding characterization of anthraquinone derivatives by stabilizing G-quadruplex DNA leads to an anticancerous activity

Anthraquinones from the roots of Morinda scabrida Craib exhibit antiproliferative activity against A549 lung cancer cells and antitubulin polymerization

Six anthraquinones were isolated from Morinda scabrida Craib, an unexplored species of Morinda found in the tropical forest of Thailand. All six anthraquinones showed cytotoxicity against A549 lung cancer cells, with the most active compound, nordamnacanthal (MS01), exhibiting the IC50 value of 16.3 ± 2.5 μM. The cytotoxic effect was dose-dependent and led to cell morphological changes characteristic of apoptosis. In addition, flow cytometric analysis showed dose-dependent apoptosis induction and the G2/M phase cell cycle arrest, which was in agreement with the tubulin polymerization inhibitory activity of MS01. Molecular docking analysis illustrated the binding between MS01 and the α/β-tubulin heterodimer at the colchicine binding site, and UV-visible absorption spectroscopy revealed the DNA binding capacity of MS01.

Hypericum roeperianum bark extract suppresses breast cancer proliferation via induction of apoptosis, downregulation of PI3K/Akt/mTOR signaling cascade and reversal of EMT

ETHNOPHARMACOLOGICAL RELEVANCE

Hypericum roeperianum is a medicinal spice traditionally used in West Africa to treat female sterility, fungal infections, and cancer. It has previously been reported that H. roeperianum exhibits cytotoxic potential by reducing the viability of cancer cells involving multidrug-resistant phenotypes, but its underlying molecular mechanism remains unknown.

AIM OF THE STUDY

The mechanistic involvement of H. roeperianum methanolic crude extract (HRC) in attenuating breast cancer progression by exploring the effects on mitochondrial apoptosis and epithelial-mesenchymal transition (EMT) was investigated.

MATERIALS AND METHODS

In the present study, we examined the anticancer properties of HRC through MTT assay, colony formation, wound healing assay, spheroid formation, DNA fragmentation and flow cytometry for cell cycle arrest, apoptosis (Annexin V/PI staining) and mitochondrial membrane potential (MMP) (JC-1) detection. In addition, western blot analysis of various proteins and quantitative real time PCR of various genes involved in apoptosis, EMT and the PI3K/Akt/mToR signal transduction pathway were performed.

RESULTS

This study revealed that HRC treatment significantly decreased breast cancer cell viability, colony forming efficiency and reduced the ability of cell migration and spheroid formation. HRC also induced apoptosis in MDA-MB-231 and MCF-7 via promoting G0/G1 cell cycle arrest, disruption of mitochondrial membrane potential and induction of DNA damage. The crude extract induced apoptosis by activating the intrinsic pathway with a stronger effect that relies on the combined potency of associated molecular markers including Bax, Bad, Bcl-2, cytochrome C, caspase-9, and cleaved-PARP. It was also found that HRC regulates the PI3K/Akt/mToR pathway. In addition, HRC inhibited EMT by expressional alteration of Vimentin and E-cadherin, as well as the regulatory transcription factors such as Snail and Slug. The in vitro findings reflected similar mechanistic approach in 4T1 cell induced syngeneic mice model, indicating the reduction of tumor volume along with the significant expressional alteration of EMT and apoptotic markers.

CONCLUSION

Taken together the findings concluded that H. roeperianum is a potential source of cytotoxic phytochemicals that exhibit abortifacient effect on breast cancer, both in vitro and in vivo, thus could further be utilized in breast cancer therapy.