Cancer:
Colorectal, renal carcinoma, glioblastoma, ovarian and cervical
Action: CSCs, anti-inflammatory
Zerumbone is isolated from Zingiber zerumbet [(L.) Roscoe ex Sm.].
Colorectal Cancer
Numerous agents from 'mother nature' (also called nutraceuticals) that have potential to both prevent and treat CRC have been identified. The most significant discoveries relate to compounds such as cardamonin, celastrol, curcumin, deguelin, diosgenin, thymoquinone, tocotrienol, ursolic acid, and zerumbone. Unlike pharmaceutical drugs, these agents modulate multiple targets, including transcription factors, growth factors, tumor cell survival factors, inflammatory pathways, and invasion and angiogenesis linked closely to CRC. We describe the potential of these dietary agents to suppress the growth of human CRC cells in culture and to inhibit tumor growth in animal models (Aggarwal et al., 2013).
Cancer Stem Cells (CSCs)
Cancer stem cells (CSCs) are a major cause of cancer treatment failure, relapse, and drug resistance and are known to be responsible for cancer cell invasion and metastasis. The Sonic hedgehog (Shh) signaling pathway is crucial to embryonic development. Intriguingly, the aberrant activation of the Shh pathway plays a critical role in developing CSCs and leads to angiogenesis, migration, invasion, and metastasis. Natural compounds and chemical structure modified derivatives from complementary and alternative medicine have received increasing attention as cancer chemo-preventives, and their anti-tumor effects have been demonstrated both in vitro and in vivo.
Compounds cyclopamine, curcumin, epigallocatechin-3-gallate, genistein, resveratrol, zerumbone, norcantharidin, and arsenic trioxide, with a focus on Shh signaling blockade, were reviewed by Huang et al. (2013) and given that Shh signaling antagonism has been clinically proven as an effective strategy against CSCs, this review may be exploitable for the development of novel anti-cancer agents from complementary and alternative medicine.
Renal Carcinoma
Sun et al. (2013) reported that zerumbone, a monosesquiterpine, shows anti-cancer effects on human RCC cells via induction of apoptosis in vitro. Human renal clear cell carcinoma 786-0 and 769-P cell lines were used as the model system. Exposure of RCC cells to zerumbone resulted in cell viability inhibition, accompanied by DNA fragmentation and increased apoptotic index. Mechanically, treatment of RCC cells with zerumbone activated caspase-3 and caspase-9 finally led to cleavage of PARR.
Taken together, our studies provided the first evidence that zerumbone imparted strong inhibitory and apoptotic effects on human RCC cells. The zerumbone-induced apoptosis might be related to the activation of the caspase cascade and deregulation of the Gli-1/Bcl-2 pathway. Our results suggest that zerumbone merit further investigation as an apoptosis inducer as well as a novel RCC chemotherapeutic agent in the clinical setting.
Glioblastoma
Zerumbone (10~50 µM) induced death of human glioblastoma multiforme (GBM8401) cells in a dose-dependent manner. Flow cytometry studies showed that zerumbone increased the percentage of apoptotic GBM cells. Zerumbone also caused caspase-3 activation and poly (ADP-ribose) polymerase (PARP) production. N-benzyloxycarbonyl -Val-Ala-Asp- fluoromethylketone (zVAD-fmk), a broad-spectrum caspase inhibitor, hindered zerumbone-induced cell death. Moreover, transfection of GBM8401 cells with WT IKKα reduced the zerumbone-induced decrease in Akt and FOXO1 phosphorylation. However, transfection with WT Akt decreased FOXO1, but not IKKα, phosphorylation.
The results suggest that inactivation of IKKα, followed by Akt and FOXO1 phosphorylation and caspase-3 activation, contributes to zerumbone-induced GBM cell apoptosis (Weng et al., 2012).
Ovarian and Cervical Cancer
A study by Abdelwahab et al., (2012) was designed to investigate the role of IL-6 and IL6 receptors in the cytotoxic effects of zerumbone in ovarian and cervical cancer cell lines (Caov-3 and HeLa, respectively). Exposure of both cancer cells to zerumbone or cisplatin demonstrated growth inhibition in a dose-dependent manner as determined by the MTT reduction assay. The studies conducted seem to suggest that zerumbone induces cell death by stimulating apoptosis better than cisplatin, based on the significantly higher percentage of apoptotic cells in zerumbone's treated cancer cells as compared to cisplatin. In addition, zerumbone and cisplatin arrest cancer cells at G2/M phase as analyzed by flow cytometry. These results indicated that zerumbone significantly decreased the levels of IL-6 secreted by both cancer cells.
This study concludes that the compound, zerumbone, inhibits cancer cell growth through the induction of apoptosis, arrests cell-cycle at G2/M phase and inhibits the secretion levels of IL-6 in both cancer cells.
References