Piscidin-1, an antimicrobial peptide from fish (hybrid striped bass morone saxatilis x M. chrysops), induces apoptotic and necrotic activity in HT1080 cells

Piscidin-1, a 22-residue cationic peptide isolated from mast cells of a hybrid striped bass, has potent antimicrobial activities against both gram-positive and -negative bacteria. To date, there is no report of its antitumor activity on any tumor cell lines. In this study, we examined the antitumor activity of a synthetic piscidin-1 peptide against several human cancer cell lines using an MTS assay and soft-agar colony-formation assay. We found that a low dose of piscidin induces both apoptosis and necrosis in HT1080 cells, as shown by annexin-V/propidium iodide and acridine orange/ethidium bromide staining, and triggers a necrotic cell death pathway in a short period with high-dose treatment. The destruction of cell membranes by piscidin-1 was demonstrated by transmission electron microscopy. Furthermore, piscidin-1 also inhibits the migration of HT1080 cells in a dose-dependent manner. This study provides the first evidence of the anticancer activity of the antimicrobial peptide, piscidin-1, with potential implications for the treatment of cancer.     

Truncated antimicrobial peptides from marine organisms retain anticancer activity and antibacterial activity against multidrug-resistant Staphylococcus aureus

Antimicrobial peptides (AMPs) were recently determined to be potential candidates for treating drug-resistant bacterial infections. The aim of this study was to develop shorter AMP fragments that combine maximal bactericidal effect with minimal synthesis cost. We first synthesized a series of truncated forms of AMPs (anti-lipopolysaccharide factor from shrimp, epinecidin from grouper, and pardaxin from Pardachirus marmoratus). The minimum inhibitory concentrations (MICs) of modified AMPs against ten bacterial species were determined. We also examined the synergy between peptide and non-peptide antibiotics. In addition, we measured the inhibitory rate of cancer cells treated with AMPs by MTS assay. We found that two modified antibacterial peptides (epinecidin-8 and pardaxin-6) had a broad range of action against both gram-positive and gram-negative bacteria. Furthermore, epinecidin and pardaxin were demonstrated to have high antibacterial and anticancer activities, and both AMPs resulted in a significant synergistic improvement in the potencies of streptomycin and kanamycin against methicillin-resistant Staphylococcus aureus. Neither AMP induced significant hemolysis at their MICs. In addition, both AMPs inhibited human epithelial carcinoma (HeLa) and fibrosarcoma (HT-1080) cell growth. The functions of these truncated AMPs were similar to those of their full-length equivalents. In conclusion, we have successfully identified shorter, inexpensive fragments with maximal bactericidal activity. This study also provides an excellent basis for the investigation of potential synergies between peptide and non-peptide antibiotics, for a broad range of antimicrobial and anticancer activities.     

Characteristics of the antitumor activities in tumor cells and modulation of the inflammatory response in RAW264.7 cells of a novel antimicrobial peptide, chrysophsin-1, from the red sea bream (Chrysophrys major)

The antimicrobial peptide, chrysophsin-1, exhibits antimicrobial activities with similar efficiencies for both gram-negative and gram-positive bacteria. In this study, we examined the antitumor activity and modulation of the inflammatory response of a synthetic chrysophsin-1 peptide. In vitro results showed that chrysophsin-1 had greater inhibitory effects against human fibrosarcoma (HT-1080), histiocytic lymphoma (U937), and epithelial carcinoma (HeLa) cells. LDH release by HeLa cells was comparable to that of an MTS assay after treatment with 1.5-3 μg/ml chrysophsin-1 for 24 h. Under SEM and TEM observations, we found no intact cell membranes after chrysophsin-1 treatment of HeLa cells for 8 h. The suggested mechanism of the cytotoxic activity of chrysophsin-1 was disruption of cancer cell membranes. In addition, we also examined caspase-3, -8, and -9 activities by Western blotting; the results excluded the participation of apoptosis in chrysophsin-1's effect on HeLa cells. Stimulation by lipopolysaccharide induced tumor necrosis factor (TNF)-α which was able to modulate chrysophsin-1 treatment of RAW264.7 cells and inhibited endogenous TNF-α release but did not block its secretion. With data from this study, we demonstrate that chrysophsin-1 has antimicrobial and antitumor activities and modulates the inflammatory response in RAW264.7 cells.     

Targeting Androgen Receptor/Src Complex Impairs the Aggressive Phenotype of Human Fibrosarcoma Cells

Background

Hormones and growth factors influence the proliferation and invasiveness of human mesenchymal tumors. The highly aggressive human fibrosarcoma HT1080 cell line harbors classical androgen receptor (AR) that responds to androgens triggering cell migration in the absence of significant mitogenesis. As occurs in many human cancer cells, HT1080 cells also express epidermal growth factor receptor (EGFR).

Experimental

Findings: We report that the pure anti-androgen Casodex inhibits the growth of HT1080 cell xenografts in immune-depressed mice, revealing a novel role of AR in fibrosarcoma progression. In HT1080 cultured cells EGF, but not androgens, robustly increases DNA synthesis. Casodex abolishes the EGF mitogenic effect, implying a crosstalk between EGFR and AR. The mechanism underlying this crosstalk has been analyzed using an AR-derived small peptide, S1, which prevents AR/Src tyrosine kinase association and androgen-dependent Src activation. Present findings show that in HT1080 cells EGF induces AR/Src Association, and the S1 peptide abolishes both the assembly of this complex and Src activation. The S1 peptide inhibits EGF-stimulated DNA synthesis, cell matrix metalloproteinase-9 (MMP-9) secretion and invasiveness of HT1080 cells. Both Casodex and S1 peptide also prevent DNA synthesis and migration triggered by EGF in various human cancer-derived cells (prostate, breast, colon and pancreas) that express AR.

Conclusion

This study shows that targeting the AR domain involved in AR/Src association impairs EGF signaling in human fibrosarcoma HT1080 cells. The EGF-elicited processes inhibited by the peptide (DNA synthesis, MMP-9 secretion and invasiveness) cooperate in increasing the aggressive phenotype of HT1080 cells. Therefore, AR represents a new potential therapeutic target in human fibrosarcoma, as supported by Casodex inhibition of HT1080 cell xenografts. The extension of these findings in various human cancer-derived cell lines highlights the conservation of this process across divergent cancer cells and identifies new potential targets in the therapeutic approach to human cancers.     

A fish antimicrobial peptide, tilapia hepcidin TH2-3, shows potent antitumor activity against human fibrosarcoma cells

As part of a continuing search for potential anticancer drug candidates from antimicrobial peptides of marine organisms, tilapia (Oreochromis mossambicus) hepcidin TH2-3 was evaluated in several tumor cell lines. The results indicated that TH2-3, a synthetic 20-mer antimicrobial peptide, specifically inhibited human fibrosarcoma cell (HT1080 cell line) proliferation and migration. The way in which TH2-3 inhibited HT1080 cell growth was then studied. TH2-3 inhibited HT1080 cell growth in a concentration-dependent manner according to an MTT analysis, which was confirmed by a soft-agar assay and AO/EtBr staining. Scanning electron microscopy revealed that TH2-3 caused lethal membrane disruption in HT1080 cancer cells, and a wound healing assay supported that TH2-3 decreased the migration of HT1080 cells. In addition, c-Jun mRNA expression was downregulated after treatment with TH2-3 for 48–96 h compared to the untreated group. These findings suggest a mechanism of cytotoxic action of TH2-3 and indicate that TH2-3 may be a promising chemotherapeutic agent against human fibrosarcoma cells.     

Lysophosphatidic acid receptor-5 negatively regulates cell motile and invasive activities of human sarcoma cell lines

LPA signaling via LPA receptors [LPA receptor-1 (LPA₁)–LPA₆] mediates the several cellular responses in cancer cells, including cell motility and invasion. In the present study, to investigate a role of LPA₅ in the cell motile and invasive activities of sarcoma cells, LPAR5 knockdown (HOSL5 and HT1080L5) cells were generated from human osteosarcoma HOS and fibrosarcoma HT1080 cells, respectively. In cell motility assays with cell culture inserts, HOSL5 and HT1080L5 cells indicated the high cell motile activities, compared with control cells. The cell invasive activities of HOSL5 and HT1080L5 cells were significantly higher than those of control cells. Moreover, the activities of matrix metalloproteinase (MMP)-2 and MMP-9 were measured by gelatin zymography. MMP-2 was significantly activated in HOSL5 cells, but not MMP-9. The elevated activities of MMP-2 and MMP-9 were found in HT1080L5 cells, in comparison with control cells. These results suggest that LPA signaling via LPA₅ negatively regulates the cell motile and invasive activities of human sarcoma cells.     

Tilapia (Oreochromis mossambicus) antimicrobial peptide, hepcidin 1-5, shows antitumor activity in cancer cells

The inhibitory function of tilapia hepcidin (TH)1-5, an antimicrobial peptide, was not examined in previous studies. In this study, we synthesized the TH1-5 peptide and tested TH1-5's antitumor activity against several tumor cell lines. We show that TH1-5 inhibited the proliferation of tumor cells and reduced colony formation in a soft agar assay. Scanning electron microscopy and transmission electron microscopy showed that TH1-5 altered the membrane structure similar to the function of a lytic peptide. Acridine orange/ethidium bromide staining, a wound-healing assay, and a flow cytometric analysis showed that TH1-5 induced necrosis with high-concentration treatment and induced apoptosis with low-concentration treatment. Inflammation is known to be closely associated with the development of cancer. TH1-5 showing anti-inflammatory effects in a previous publication induced us to evaluate the anti-inflammatory effects in cancer cell lines through the expressions of immune-related genes after being treated with the TH1-5 peptide. However, real-time qualitative RT-PCR indicated that TH1-5 treatment induced downregulation of the expressions of interleukin (IL)-6, IL-8, IL-12, IL-15, interferon-γ, CTSG, caspase-7, and Bcl-2, and upregulation of IL-2 and CAPN5 in HeLa cells, and upregulation of IL-8 and CTSG in HT1080 cells. These results suggest that TH1-5 possibly induces an inflammatory response in HeLa cells, but not in HT1080 cells. Overall, these results indicate that TH1-5 possesses the potential to be a novel peptide for cancer therapy.     

Jaeumganghwa-Tang Induces Apoptosis via the Mitochondrial Pathway and Lactobacillus Fermentation Enhances Its Anti-Cancer Activity in HT1080 Human Fibrosarcoma Cells

Jaeumganghwa-tang (JGT, Zi-yin-jiang-huo-tang in Chinese and Jiin-koka-to in Japanese) is an oriental herbal formula that has long been used as a traditional medicine to treat respiratory and kidney diseases. Recent studies revealed that JGT exhibited potent inhibitory effects on allergies, inflammation, pain, convulsions, and prostate hyperplasia. Several constituent herbs in JGT induce apoptotic cancer cell death. However, the anti-cancer activity of JGT has not been examined. In this study, we investigated the anti-cancer effects of JGT using highly tumorigenic HT1080 human fibrosarcoma cells and elucidated the underlying mechanisms. In addition, we examined whether the Lactobacillus fermentation of JGT enhanced its anti-cancer activity using an in vivo xenograft model because fermentation of herbal extracts is thought to strengthen their therapeutic effects. Data revealed that JGT suppressed the growth of cancer cells efficiently by stimulating G1 cell cycle arrest and then inducing apoptotic cell death by causing mitochondrial damage and activating caspases. The phosphorylation of p38 and ERK also played a role in JGT-induced cell death. In vitro experiments demonstrated that JGT fermented with Lactobacillus acidophilus, designated fJGT162, elicited similar patterns of cell death as did non-fermented JGT. Meanwhile, the daily oral administration of 120 mg/kg fJGT162 to HT1080-bearing BALB/c nude mice suppressed tumor growth dramatically (up to 90%) compared with saline treatment, whereas the administration of non-fermented JGT suppressed tumor growth by ~70%. Collectively, these results suggest that JGT and fJGT162 are safe and useful complementary and alternative anti-cancer herbal therapies, and that Lactobacillus fermentation improves the in vivo anti-cancer efficacy of JGT significantly.     

Syntheses and structure–activity relationship studies of N-substituted-β-d-glucosaminides as selective cytotoxic agents

Twenty-four diosgenyl saponins bearing cinnamoyl, carbamido and thiosemicarbazone groups were synthesized concisely. The cytotoxicities of the synthetic compounds on six human caner cell lines were evaluated employing MTT method. Structure–activity relationship could be observed, and two of the synthesized compounds (5c and 5f) exhibited selective inhibition on HeLa and MCF-7 cells, while three of them (5d, 5f and 5h) showed strong inhibition against HT1080.     

Combination treatment with arsenic trioxide and irradiation enhances cell-killing effects in human fibrosarcoma cells in vitro and in vivo through induction of both autophagy and apoptosis

The traditional treatments for fibrosarcoma have limited efficacy. Therefore, new therapeutic strategies and/or new adjuvant drugs still need to be explored. Accumulating evidence indicates that programmed cell death (PCD) is closely related to anticancer therapy. Many studies have shown that tumor cells treated with anticancer drugs experience the induction of type I PCD, apoptosis, and type II PCD, autophagy. In the present study, we investigated the anticancer effects of ionizing radiation (IR) combined with arsenic trioxide (ATO) in human fibrosarcoma cells in vitro and in xenograft tumors in SCID mice in vivo. We found that IR increased the population of HT1080 cells in the G₂/M phase in a time-dependent manner within 9 h. IR treatment combined with ATO at this time point induced a significantly prolonged G₂/M arrest and consequently enhanced cell death. Furthermore, damage of mitochondria membrane potential could be involved in the underlying mechanisms. The enhanced cytotoxic effect of combined treatment occurred due to the increased induction of more autophagy and apoptosis through the inhibition of Akt and the activation of ERK1/2 signaling pathways in HT1080 cells. The combined treatment of HT1080 cells pretreated with Z-VAD or 3-MA resulted in a significant reduction in AO-positive cells, apoptotic cells and cytotoxicity. In in vivo studies, the combination of IR and ATO significantly reduced the tumor volume in SCID mice that had received a subcutaneous injection of HT1080 cells. The data suggest that a combination of IR and ATO could be a new potential therapeutic strategy for the treatment of fibrosarcoma.     

Dieckol from Ecklonia cava suppresses the migration and invasion of HT1080 cells by inhibiting the focal adhesion kinase pathway downstream of Rac1-ROS signaling

We have previously isolated dieckol, a nutrient polyphenol compound, from the brown alga, Ecklonia cava (Lee et al., 2010a). Dieckol shows both antitumor and antioxidant activity and thus is of special interest for the development of chemopreventive and chemotherapeutic agents against cancer. However, the mechanism by which dieckol exerts its antitumor activity is poorly understood. Here, we show that dieckol, derived from E. cava, inhibits migration and invasion of HT1080 cells by scavenging intracellular reactive oxygen species (ROS). H₂O₂ or integrin signal-mediated ROS generation increases migration and invasion of HT1080 cells, which correlates with Rac1 activation and increased expression and phosphorylation of focal adhesion kinase (FAK). Rac1 activation is required for ROS generation. Depletion of FAK by siRNA suppresses Rac1-ROS-induced cell migration and invasion. Dieckol treatment attenuated intracellular ROS levels and activation of Rac1 as well as expression and phosphorylation of FAK. Dieckol treatment also decreases complex formation of FAK-Src-p130Cas and expression of MMP2, 9, and 13. These results suggest that the Rac1-ROS-linked cascade enhances migration and invasion of HT1080 cells by inducing expression of MMPs through activation of the FAK signaling pathway, whereas dieckol downregulates FAK signaling through scavenging intracellular ROS. This finding provides new insights into the mechanisms by which dieckol is able to suppress human cancer progresssion and metastasis. Therefore, we suggest that dieckol is a potential therapeutic agent for cancer treatment.     

Inhibitory effects of p-dodecylaminophenol on the invasiveness of human fibrosarcoma cell line HT1080

Cancer is a major cause of death, and the development of new anticancer drugs is urgently needed. Invasion and metastasis are the primary causes of death due to cancer rather than growth of the primary tumor. In the current study, we examined the anti-invasive effects of p-dodecylaminophenol (1), which was developed based on N-(4-hydroxyphenyl)retinamide (2), a synthetic amide of all-trans-retinoic acid (3). In HT1080 cells 1 inhibited growth, induced apoptosis and arrested the cell cycle in S phase in a dose-dependent manner. In addition, 1 significantly suppressed cell invasion, and the activity and mRNA expression of matrix metalloproteinase-9 (MMP-9). Furthermore, the expression of the reversion-inducing cysteine-rich protein with Kazal motifs (RECK), which is a negative regulator of MMP-9, was increased by treatment with 1. These results suggest that 1 could be an effective anti-cancer agent that suppresses cell growth through apoptosis induction and cell cycle arrest, which also inhibits cell invasion by decreasing MMP-9 expression due to an increase in RECK. Compound 1 might be useful clinically as a new and potent anticancer agent that could overcome adverse side effects of the retinoids.     

Cell specificity and molecular mechanism of antibacterial and antitumor activities of carboxyl-terminal RWL-tagged antimicrobial peptides

Antimicrobial peptides (AMPs) constitute a diverse class of naturally occurring or synthetic antimicrobial molecules that have potential for use in the treatment of drug-resistant infections. Several undesirable properties of AMPs, however, may ultimately hinder their development as antimicrobial agents. Thus, new synthetic strategies, including primarily the de novo design of AMPs, urgently need to be developed. In this study, a series of peptides, H-(RWL) _n (n = 1, 2, 3, 4, or 5), were designed. H represents GLRPKYS from the C-terminal sequence of AvBD-4. Our results showed that these RWL-tagged peptides can kill not only bacteria but also human hepatocellular carcinoma HepG2 cells. However, the peptide tagged with two repeats of RWL (GW13) showed less affinity to human embryonic lung fibroblast MRC-5 cells or human red blood cells (hRBCs) than HepG2 cells. These results demonstrated that GW13, with high amphiphilicity, exerted great selectivity toward bacteria and cancer cells, sparing host mammalian cells. The mechanism of action against bacteria was elucidated through combined studies of scanning electron microscopy (SEM) and fluorescence assays, showing that the peptide possessed membrane-lytic activities against microbial cells. The fluorescence assays illustrated that GW13 induced apoptosis in HepG2 cells. The cell morphology of HepG2 cells, observed by SEM, further illustrated that GW13 causes cell death by damaging the cell membrane. Our results indicate that GW13 has considerable potential for future development as an antimicrobial and antitumor agent.     

Abrus abrin derived peptides induce apoptosis by targeting mitochondria in HeLa cells

In our previous study, Abrus abrin derived peptide fraction (ABP) with molecular weight in range of 600-1500 Da was shown to have potent antitumor activity in Dalton's lymphoma (DL) tumor bearing mice. The purpose of this study was to elucidate the mechanism of mitochondrial apoptosis induced by the peptide fraction. ABP was found to have selective antiproliferative activity (10 ng-100 ng/ml) on several tumor cell lines in vitro without having any cytotoxic effect on normal cell lines with a dose of 1000 ng/ml. Analysis of the growth inhibitory mechanism in HeLa cells revealed DNA fragmentation with appearance of the sub G₀/G₁ peak indicative of apoptosis. Further investigation results showed that the apoptotic machinery of HeLa induced by ABP was associated with the release of reactive oxygen species, a drop in mitochondrial transmembrane potential, upregulation of Bax, downregulation of Bcl-2, and activation of caspase-3. The peptide fraction was found to target mitochondria of HeLa cells as observed by confocal microscopy. This peptide fraction offers a source of mitochondria penetrating peptides which might have therapeutic induction of apoptosis in cancer cells.     

Peptide gomesin triggers cell death through L-type channel calcium influx,MAPK/ERK,PKC and PI3K signaling and generation of reactive oxygen species

Gomesin is an antimicrobial peptide isolated from hemocytes of a common Brazilian tarantula spider named Acanthoscurria gomesiana. This peptide exerts antitumor activity in vitro and in vivo by an unknown mechanism. In this study, the cytotoxic mechanism of gomesin in human neuroblastoma SH-SY5Y and rat pheochromocytoma PC12 cells was investigated. Gomesin induced necrotic cell death and was cytotoxic to SH-SY5Y and PC12 cells. The peptide evoked a rapid and transient elevation of intracellular calcium levels in Fluo-4-AM loaded PC12 cells, which was inhibited by nimodipine, an L-type calcium channel blocker. Preincubation with nimodipine also inhibited cell death induced by gomesin in SH-SY5Y and PC12 cells. Gomesin-induced cell death was prevented by the pretreatment with MAPK/ERK, PKC or PI3K inhibitors, but not with PKA inhibitor. In addition, gomesin generated reactive oxygen species (ROS) in SH-SY5Y cells, which were blocked with nimodipine and MAPK/ERK, PKC or PI3K inhibitors. Taken together, these results suggest that gomesin could be a useful anticancer agent, which mechanism of cytotoxicity implicates calcium entry through L-type calcium channels, activation of MAPK/ERK, PKC and PI3K signaling as well as the generation of reactive oxygen species.     

Chromosome-mediated transfer of murine alleles for hypoxanthine-guanine phosphoribosyl transferase (HGPRT) and ouabain resistance into human cell lines

Genetic drug-resistance markers were transferred via purified metaphase chromosomes from mouse L cells into the human fibrosarcoma line HT1080 and HeLa S3 cells. Interspecific chromosome-mediated transfer of hypoxanthine-guanine phosphoribosyl transferase (HGPRT; EC 2.4.2.8) from mouse L cells into HGPRT^– HT1080 cells occurred at a frequency of approximately 1×10^–7. The presence of the mouse allele for HGPRT in transferent isolates was confirmed by isoelectric focusing. Transfer of ouabain resistance from mouse L cells to HT1080 and HeLa S3 cells occurred at an average frequency of approximately 4×10^–7. Expression of the mouse trait in transferent isolates was confirmed by their ability to withstand doses of ouabain which would be lethal to spontaneous ouabain-resistant mutants of the human cells but not to mouse L cells. Ouabain-resistant transferents of human cells showed 10⁴- to >10⁵-fold enhanced drug resistance, characteristic of either wild-type or mutant alleles, respectively, from ouabain-resistant donor L cells. Unstable expression of the transferred phenotypes in the absence of selection was seen in some isolates, but expression was lost at slow rates.This work was supported by National Institutes of Health Grant GM30383/21665 to RMB, Core Grants CA14051 to S. E. Luria and CA24538 to E. Mihich, and institutional predoctoral Training Grant GM07287.     

Entamoeba histolytica Induces Cell Death of HT29 Colonic Epithelial Cells via NOX1-Derived ROS

Entamoeba histolytica, which causes amoebic colitis and occasionally liver abscess in humans, is able to induce host cell death. However, signaling mechanisms of colon cell death induced by E. histolytica are not fully elucidated. In this study, we investigated the signaling role of NOX in cell death of HT29 colonic epithelial cells induced by E. histolytica. Incubation of HT29 cells with amoebic trophozoites resulted in DNA fragmentation that is a hallmark of apoptotic cell death. In addition, E. histolytica generate intracellular reactive oxygen species (ROS) in a contact-dependent manner. Inhibition of intracellular ROS level with treatment with DPI, an inhibitor of NADPH oxidases (NOXs), decreased Entamoeba-induced ROS generation and cell death in HT29 cells. However, pan-caspase inhibitor did not affect E. histolytica-induced HT29 cell death. In HT29 cells, catalytic subunit NOX1 and regulatory subunit Rac1 for NOX1 activation were highly expressed. We next investigated whether NADPH oxidase 1 (NOX1)-derived ROS is closely associated with HT29 cell death induced by E. histolytica. Suppression of Rac1 by siRNA significantly inhibited Entamoeba-induced cell death. Moreover, knockdown of NOX1 by siRNA, effectively inhibited E. histolytica-triggered DNA fragmentation in HT29 cells. These results suggest that NOX1-derived ROS is required for apoptotic cell death in HT29 colon epithelial cells induced by E. histolytica.     

In vitro decreases of the fibrinolytic potential of cultured human fibrosarcoma cell line, HT1080, by Nigella sativa oil

It is generally accepted that the fibrinolytic potential of tumor cells is related to their malignant phenotype. In the present study, Nigella sativa oil (NSO) was studied to evaluate its effect on the fibrinolytic potential of the fibosarcoma cell line HT1080 to elucidate whether this oil might have an antitumor activity through its modulation of the fibrinolytic potential of such cells. NSO produced a concentration-dependent inhibition of tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA) and plasminogen activator inhibitor type 1 (PAI-1). When subconfluent HT1080 cells were conditioned with oil, a concentration (0.0-200 microg oil/ml)-dependent decrease in t-PA, u-PA and PAI-1 antigen was observed. There was also a concentration-dependent decrease (from 0.0 to 112.5 microg oil/ml) in the confluent cultures. The results showed that blackseed oil decreases the fibrinolytic potential of the human fibrosarcoma cell line (HT1080) in vitro, implying that inhibition of local tumor invasion and metastasis may be one such mechanism.     

A Novel Herbal Medicine,KIOM-C,Induces Autophagic and Apoptotic Cell Death Mediated by Activation of JNK and Reactive Oxygen Species in HT1080 Human Fibrosarcoma Cells

KIOM-C was recently demonstrated to have anti-metastatic activity in highly malignant cancer cells via suppression of NF-κB-mediated MMP-9 activity. In addition, it was reported to be effective for clearance of the influenza virus by increasing production of anti-viral cytokines, such as TNF-α and IFN-γ, and efficacious in the treatment of pigs suffering from porcine circovirus-associated disease (PCVAD). In this study, we investigated whether KIOM-C induces cancer cell death and elucidated the underlying anti-cancer mechanisms. In addition, we examined whether KIOM-C oral administration suppresses in vivo tumor growth of HT1080 cells in athymic nude mice. We initially found that KIOM-C at concentrations of 500 and 1000 µg/ml caused dose- and time-dependent cell death in cancer cells, but not normal hepatocytes, to approximately 50% of control levels. At the early stage of KIOM-C treatment (12 h), cells were arrested in G₁ phase, which was accompanied by up-regulation of p21 and p27, down-regulation of cyclin D1, and subsequent increases in apoptotic and autophagic cells. Following KIOM-C treatment, the extent of caspase-3 activation, PARP cleavage, Beclin-1 expression, and LC3-II conversion was remarkably up-regulated, but p62 expression was down-regulated. Phosphorylation of AMPK, ULK, JNK, c-jun, and p53 was increased significantly in response to KIOM-C treatment. The levels of intracellular ROS and CHOP expression were also increased. In particular, the JNK-specific inhibitor SP600125 blocked KIOM-C-induced ROS generation and CHOP expression almost completely, which consequently almost completely rescued cell death, indicating that JNK activation plays a critical role in KIOM-C-induced cell death. Furthermore, daily oral administration of 85 and 170 mg/kg KIOM-C efficiently suppressed the tumorigenic growth of HT1080 cells, without systemic toxicity. These results collectively suggest that KIOM-C efficiently induces cancer cell death by both autophagy and apoptosis via activation of JNK signaling pathways, and KIOM-C represents a safe and potent herbal therapy for treating malignancies.