Hernandezine

Hernandezine, a Bisbenzylisoquinoline Alkaloid with Selective Inhibitory Activity against Multidrug-Resistance-Linked ATP-Binding Cassette Drug Transporter ABCB1.[Pubmed:27504669]

J Nat Prod. 2016 Aug 26;79(8):2135-42.

The overexpression of ATP-binding cassette (ABC) drug transporter ABCB1 (P-glycoprotein, MDR1) is the most studied mechanism of multidrug resistance (MDR), which remains a major obstacle in clinical cancer chemotherapy. Consequently, resensitizing MDR cancer cells by inhibiting the efflux function of ABCB1 has been considered as a potential strategy to overcome ABCB1-mediated MDR in cancer patients. However, the task of developing a suitable modulator of ABCB1 has been hindered mostly by the lack of selectivity and high intrinsic toxicity of candidate compounds. Considering the wide range of diversity and relatively nontoxic nature of natural products, developing a potential modulator of ABCB1 from natural sources is particularly valuable. Through screening of a large collection of purified bioactive natural products, Hernandezine was identified as a potent and selective reversing agent for ABCB1-mediated MDR in cancer cells. Experimental data demonstrated that the bisbenzylisoquinoline alkaloid Hernandezine is selective for ABCB1, effectively inhibits the transport function of ABCB1, and enhances drug-induced apoptosis in cancer cells. More importantly, Hernandezine significantly resensitizes ABCB1-overexpressing cancer cells to multiple chemotherapeutic drugs at nontoxic, nanomolar concentrations. Collectively, these findings reveal that Hernandezine has great potential to be further developed into a novel reversal agent for combination therapy in MDR cancer patients.

A novel AMPK activator hernandezine inhibits LPS-induced TNFalpha production.[Pubmed:28978028]

Oncotarget. 2017 Jun 5;8(40):67218-67226.

Here, we found that Hernandezine, a novel AMPK activator, inhibited LPS-induced TNFalpha expression/production in human macrophage cells (THP-1 and U937 lines). Activation of AMPK is required for Hernandezine-induced anti-LPS response. AMPKalpha shRNA or dominant negative mutation (T172A) blocked Hernandezine-induced AMPK activation, which almost completely reversed anti-LPS activity by Hernandezine. Exogenous expression of the constitutively activate AMPKalpha (T172D, caAMPKalpha) also suppressed TNFalpha production by LPS. Remarkably, Hernandezine was unable to further inhibit LPS-mediated TNFalpha production in caAMPKalpha-expressing cells. Hernandezine inhibited LPS-induced reactive oxygen species (ROS) production and nuclear factor kappa B (NFkappaB) activation. Treatment of Hernandezine in ex-vivo cultured primary human peripheral blood mononuclear cells (PBMCs) also largely attenuated LPS-induced TNFalpha production. Together, we conclude that AMPK activation by Hernandezine inhibits LPS-induced TNFalpha production in macrophages/monocytes.

Hernandezine, a novel AMPK activator induces autophagic cell death in drug-resistant cancers.[Pubmed:26811496]

Oncotarget. 2016 Feb 16;7(7):8090-104.

Drug resistance hinder most cancer chemotherapies and leads to disease recurrence and poor survival of patients. Resistance of cancer cells towards apoptosis is the major cause of these symptomatic behaviours. Here, we showed that isoquinoline alkaloids, including liensinine, isoliensinine, dauricine, cepharanthine and Hernandezine, putatively induce cytotoxicity against a repertoire of cancer cell lines (HeLa, A549, MCF-7, PC3, HepG2, Hep3B and H1299). Proven by the use of apoptosis-resistant cellular models and autophagic assays, such isoquinoline alkaloid-induced cytotoxic effect involves energy- and autophagy-related gene 7 (Atg7)-dependent autophagy that resulted from direct activation of AMP activated protein kinase (AMPK). Hernandezine possess the highest efficacy in provoking such cell death when compared with other examined compounds. We confirmed that isoquinoline alkaloid is structurally varied from the existing direct AMPK activators. In conclusion, isoquinoline alkaloid is a new class of compound that induce autophagic cell death in drug-resistant fibroblasts or cancers by exhibiting its direct activation on AMPK.

Plant alkaloids, tetrandrine and hernandezine, inhibit calcium-depletion stimulated calcium entry in human and bovine endothelial cells.[Pubmed:8649222]

Life Sci. 1996;58(25):2327-35.

Depletion of internal Ca2+ stores causes capacitative Ca2+ entry which occurs through non-selective cation channels sensitive to blockade by SK&F 96365. Recently, alkaloids of Chinese herbal medicinal origin, tetrandrine and Hernandezine, have been shown to possess actions including inhibition of Ca2+ channels in non-excitable cell types. In this study, we compared the actions of these novel inhibitors to those of SK&F 96365 in fura-2-loaded endothelial cells from human umbilical vein and bovine pulmonary artery. Depletion of Ca2+ from the internal stores was accomplished in Ca(2+)-free medium using an endoplasmic reticulum Ca2+ pump inhibitor, cyclopiazonic acid (CPA) or receptor agonists, histamine and bradykinin. Stimulation with histamine or bradykinin caused a marked and rapid transient increase in Ca2+ signal whereas CPA caused a smaller amplitude increase of longer duration. Restoring Ca2+ to the medium caused marked and sustained increases in the fluorescence indicating movement of Ca2+ into the cytosol presumably stimulated by the emptied Ca2+ stores. SK&F 96365 as well as tetrandrine and Hernandezine antagonized depletion-induced Ca2+ entry. The results suggest that these putative inhibitors interact with Ca2+ entry triggered by depletion of the internal Ca2+ stores and their action is presumed to be on the non-selective cation channels. Their effectiveness may be enhanced by the mechanisms which lead to the opening of the Ca2+ influx channel.