Fucoidan derived from Undaria pinnatifida induces apoptosis in human hepatocellular carcinoma SMMC-7721 cells via the ROS-mediated mitochondrial pathway

Anticancer effects of different seaweeds on human colon and breast cancers

Seafoods and seaweeds represent some of the most important reservoirs of new therapeutic compounds for humans. Seaweed has been shown to have several biological activities, including anticancer activity. This review focuses on colorectal and breast cancers, which are major causes of cancer-related mortality in men and women. It also describes various compounds extracted from a range of seaweeds that have been shown to eradicate or slow the progression of cancer. Fucoidan extracted from the brown algae Fucus spp. has shown activity against both colorectal and breast cancers. Furthermore, we review the mechanisms through which these compounds can induce apoptosis in vitro and in vivo. By considering the ability of compounds present in seaweeds to act against colorectal and breast cancers, this review highlights the potential use of seaweeds as anticancer agents.

Anti-metastasis effect of fucoidan from Undaria pinnatifida sporophylls in mouse hepatocarcinoma Hca-F cells

Metastasis is one of the major causes of cancer-related death. It is a complex biological process involving multiple genes, steps, and phases. It is also closely connected to many biological activities of cancer cells, such as growth, invasion, adhesion, hematogenous metastasis, and lymphatic metastasis. Fucoidan derived from Undaria pinnatifida sporophylls (Ups-fucoidan) is a sulfated polysaccharide with more biological activities than other fucoidans. However, there is no information on the effects of Ups-fucoidan on tumor invasion and metastasis. We used the mouse hepatocarcinoma Hca-F cell line, which has high invasive and lymphatic metastasis potential in vitro and in vivo, to examine the effect of Ups-fucoidan on cancer cell invasion and metastasis. Ups-fucoidan exerted a concentration- and time-dependent inhibitory effect on tumor metastasis in vivo and inhibited Hca-F cell growth, migration, invasion, and adhesion capabilities in vitro. Ups-fucoidan inhibited growth and metastasis by downregulating vascular endothelial growth factor (VEGF) C/VEGF receptor 3, hepatocyte growth factor/c-MET, cyclin D1, cyclin-dependent kinase 4, phosphorylated (p) phosphoinositide 3-kinase, p-Akt, p-extracellular signal regulated kinase (ERK) 1/2, and nuclear transcription factor-κB (NF-κB), and suppressed adhesion and invasion by downregulating L-Selectin, and upregulating protein levels of tissue inhibitor of metalloproteinases (TIMPs). The results suggest that Ups-fucoidan suppresses Hca-F cell growth, adhesion, invasion, and metastasis capabilities and that these functions are mediated through the mechanism involving inactivation of the NF-κB pathway mediated by PI3K/Akt and ERK signaling pathways.

Puerarin inhibits growth and induces apoptosis in SMMC-7721 hepatocellular carcinoma cells

Puerarin, a predominant isoflavonoid compound extracted from the Chinese medicinal herb Radix Puerariae, is considered to exhibit an antitumor effect. In the present study, the effects of puerarin on SMMC-7721 human hepatocellular carcinoma cells were investigated. Cell viability was assessed by MTT assay. Apoptosis was detected by flow cytometry with Annexin V-fluorescein isothiocyante staining and morphological observation of nuclear changes by Hoechst staining. The mitochondrial membrane potential (MMP) was monitored using rhodamine 123. The generation of reactive oxygen species (ROS) was quantified using dichloro‑dihydro‑fluorescein diacetate. Polymerase chain reaction and western blot analysis were used to detect the expression levels of apoptosis‑associated genes. The results revealed that high concentrations of puerarin (500, 1,000 and 1,500 µg/ml) significantly inhibited the proliferation of SMMC-7721 cells in a time- and dose-dependent manner. Simultaneously, apoptotic rates were increased and cell morphology was changed following puerarin treatment. Furthermore, puerarin‑induced apoptosis of SMMC-7721 cells was associated with loss of MMP and generation of ROS. Puerarin treatment increased caspase‑3,8,9 and apoptosis‑inducing factor (AIF) mRNA expression levels in SMMC‑7721 cells, while the phosphorylation levels of P38, extracellular signal‑regulated kinase (ERK1) and c-Jun N‑terminal kinase were also increased. Furthermore, caspase-9 and AIF protein expression was upregulated. In conclusion, puerarin inhibited proliferation and induced apoptosis in SMMC‑7721 cells via the mitochondria‑dependent pathway; however, the specific mechanisms require further investigation.

β-elemene reverses the drug resistance of A549/DDP lung cancer cells by activating intracellular redox system, decreasing mitochondrial membrane potential and P-glycoprotein expression, and inducing apoptosis

BACKGROUND

β-elemene (β-ELE) injection is a new anticancer drug extracted from Curcuma zedoaria Roscoe that has been widely used to treat malignant tumors. Recent studies show that β-ELE reverses the drug resistance of tumor cells. To explore the possible mechanisms of β-ELE, we investigated its effects on cisplatin (DDP)-resistant human lung adenocarcinoma A549/DDP cells.

METHODS

The effects of β-ELE on the growth of A549/DDP cells in vitro were determined by MTT assay. Apoptosis was assessed by fluorescence microscopy with Hoechst 33258 staining, flow cytometry with Annexin V-FITC/propium iodide double staining; mitochondrial membrane potential using JC-1 fluorescence probe and laser confocal scanning microscopy, and intracellular reactive oxygen species levels were measured by 2',7'-dichlorfluorescein-diacetate staining and flow cytometry; and contents of cytosolic glutathione were determined by glutathione assay kits. Intracellular Rhodamine-123 fluorescence intensity was detected by flow cytometry, and the expression of P-glycoprotein (P-gp) was detected by Western blotting.

RESULTS

β-ELE inhibited the proliferation of A549/DDP cells in a time- and dose-dependent manner. Furthermore, β-ELE enhanced the sensitivity of A549/DDP cells to cisplatin and reversed the drug resistance of A549/DDP cells. Consistent with a role in activating apoptosis, β-ELE decreased mitochondrial membrane potential, increased intracellular reactive oxygen species concentration and intracellular accumulation of Rhodamine-123, decreased the cytoplasmic glutathione levels and the expression of P-gp in a time- and dose-dependent manner.

CONCLUSIONS

These results define a pathway of β-ELE function that involves decreased mitochondrial membrane potential and P-gp expression activated intracellular redox system, and induced apoptosis leading to reverse drug resistance.

β-elemene reverses the drug resistance of lung cancer A549/DDP cells via the mitochondrial apoptosis pathway

β-elemene (β-ELE) is a new anticancer drug extracted from Curcuma zedoaria Roscoe and has been widely used to treat malignant tumors. Recent studies have demonstrated that β-ELE reverses the drug resistance of tumor cells. To explore the possible mechanisms of action of β-ELE, we investigated its effects on cisplatin-resistant human lung adenocarcinoma A549/DDP cells. The effects of β-ELE on the growth of A549/DDP cells in vitro were determined by MTT assay. Apoptosis was assessed by fluorescence microscopy with Hoechst 33258 staining and flow cytometry with Annexin V-FITC/PI double staining. Mitochondrial membrane potential was assessed using JC-1 fluorescence probe and laser confocal scanning microscopy, and intracellular reactive oxygen species levels were measured by 2',7'-dichlorofluorescein-diacetate staining and flow cytometry. Cytosolic glutathione content was determined using GSH kits. The expression of cytochrome c, caspase-3, procaspase-3 and the Bcl-2 family proteins was assessed by western blotting. The results demonstrated that β-ELE inhibited the proliferation of A549/DDP cells in a time- and dose-dependent manner. Furthermore, β-ELE enhanced the sensitivity of A549/DDP cells to cisplatin and reversed the drug resistance of A549/DDP cells. Consistent with a role in activating apoptosis, β-ELE decreased mitochondrial membrane potential, increased intracellular reactive oxygen species concentration and decreased the cytoplasmic glutathione levels in a time- and dose-dependent manner. The combination of β-ELE and cisplatin enhanced the protein expression of cytochrome c, caspase-3 and Bad, and reduced protein levels of Bcl-2 and procaspase-3 in the A549/DDP lung cancer cells. These results define a pathway of procaspase‑3-β-ELE function that involves decreased mitochondrial membrane potential, leading to apoptosis triggered by the release of cytochrome c into the cytoplasm and the modulation of apoptosis-related genes. The reversal of drug resistance of the A549/DDP cell line by β-ELE may be derived from its effect in inducing apoptosis.

Fucoidan as a marine anticancer agent in preclinical development

Fucoidan is a fucose-containing sulfated polysaccharide derived from brown seaweeds, crude extracts of which are commercially available as nutritional supplements. Recent studies have demonstrated antiproliferative, antiangiogenic, and anticancer properties of fucoidan in vitro. Accordingly, the anticancer effects of fucoidan have been shown to vary depending on its structure, while it can target multiple receptors or signaling molecules in various cell types, including tumor cells and immune cells. Low toxicity and the in vitro effects of fucoidan mentioned above make it a suitable agent for cancer prevention or treatment. However, preclinical development of natural marine products requires in vivo examination of purified compounds in animal tumor models. This review discusses the effects of systemic and local administration of fucoidan on tumor growth, angiogenesis, and immune reaction and whether in vivo and in vitro results are likely applicable to the development of fucoidan as a marine anticancer drug.

Silybin-mediated inhibition of Notch signaling exerts antitumor activity in human hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is a global health burden that is associated with limited treatment options and poor patient prognoses. Silybin (SIL), an antioxidant derived from the milk thistle plant (Silybum marianum), has been reported to exert hepatoprotective and antitumorigenic effects both in vitro and in vivo. While SIL has been shown to have potent antitumor activity against various types of cancer, including HCC, the molecular mechanisms underlying the effects of SIL remain largely unknown. The Notch signaling pathway plays crucial roles in tumorigenesis and immune development. In the present study, we assessed the antitumor activity of SIL in human HCC HepG2 cells in vitro and in vivo and explored the roles of the Notch pathway and of the apoptosis-related signaling pathway on the activity of SIL. SIL treatment resulted in a dose- and time-dependent inhibition of HCC cell viability. Additionally, SIL exhibited strong antitumor activity, as evidenced not only by reductions in tumor cell adhesion, migration, intracellular glutathione (GSH) levels and total antioxidant capability (T-AOC) but also by increases in the apoptotic index, caspase3 activity, and reactive oxygen species (ROS). Furthermore, SIL treatment decreased the expression of the Notch1 intracellular domain (NICD), RBP-Jκ, and Hes1 proteins, upregulated the apoptosis pathway-related protein Bax, and downregulated Bcl2, survivin, and cyclin D1. Notch1 siRNA (in vitro) or DAPT (a known Notch1 inhibitor, in vivo) further enhanced the antitumor activity of SIL, and recombinant Jagged1 protein (a known Notch ligand in vitro) attenuated the antitumor activity of SIL. Taken together, these data indicate that SIL is a potent inhibitor of HCC cell growth that targets the Notch signaling pathway and suggest that the inhibition of Notch signaling may be a novel therapeutic intervention for HCC.

The anticancer effect of fucoidan in PC-3 prostate cancer cells

Fucoidan, a sulfated polysaccharide, has a variety of biological activities, such as anti-cancer, anti-angiogenic and anti-inflammatory. However, the mechanisms of action of fucoidan as an anti-cancer agent have not been fully elucidated. The present study examined the anti-cancer effect of fucoidan obtained from Undaria pinnatifida in PC-3 cells, human prostate cancer cells. Fucoidan induced the apoptosis of PC-3 cells by activating both intrinsic and extrinsic pathways. The induction of apoptosis was accompanied by the activation of extracellular signal-regulated kinase mitogen-activated protein kinase (ERK1/2 MAPK) and the inactivation of p38 MAPK and phosphatidylinositol 3-kinase (PI3K)/Akt. In addition, fucoidan also induced the up-regulation of p21Cip1/Waf and down-regulation of E2F-1 cell-cycle-related proteins. Furthermore, in the Wnt/β-catenin pathway, fucoidan activated GSK-3β that resulted in the decrease of β-catenin level, followed by the decrease of c-myc and cyclin D1 expressions, target genes of β-catenin in PC-3 cells. These results suggested that fucoidan treatment could induce intrinsic and extrinsic apoptosis pathways via the activation of ERK1/2 MAPK, the inactivation of p38 MAPK and PI3K/Akt signaling pathway, and the down-regulation of Wnt/β-catenin signaling pathway in PC-3 prostate cancer cells. These data support that fucoidan might have potential for the treatment of prostate cancer.