Reforms of regulatory pathways for approval of new antineoplastic drugs in Japan from 2004 to 2019 and accompanying changes in pivotal clinical trial designs.

Background The Japanese Pharmaceuticals and Medical Devices Agency (PMDA) was established in 2004. Since then, various pieces of legislation, notices, and guidelines have been issued, and the regulatory approval pathways for domestic drugs have been diversified. However, the effects of these measures have not been fully examined. We examined the impact of these measures on the approval of antineoplastic drugs and the design of pivotal clinical trials for efficacy assessment by the PMDA. Methods We collected data on the antineoplastic drugs approved by the PMDA in fiscal years 2004-2019. We extracted the approval review pathways and the pivotal clinical trial designs from the PMDA review reports, and analyzed them to identify patterns. Results In total, 387 indications in oncology were approved by the PMDA in fiscal years 2004-2019, or 365 indications excluding multiple regulatory pathways. The number of approved indications generally increased year on year (p < 0.001). The largest number of approved indications was under the Orphan Drug Designation (31%, 114/365) and this continues to increase (p < 0.001). In the 288 indications for which clinical trial data were submitted for review, the pivotal clinical trial designs changed significantly (p < 0.001) after the guideline on clinical evaluation for antineoplastic drugs was revised in 2006. Conclusion The number of indications in oncology approved by the PMDA has been increasing over the past 16 years, alongside changes in regulatory pathways. The 2006 guideline on clinical evaluation had a particular impact on pivotal clinical trial designs.

Lamellarin 14, a derivative of marine alkaloids, inhibits the T790M/C797S mutant epidermal growth factor receptor.

The emergence of acquired resistance is a major concern associated with molecularly targeted kinase inhibitors. The C797S mutation in the epidermal growth factor receptor (EGFR) confers resistance to osimertinib, a third-generation EGFR-tyrosine kinase inhibitor (EGFR-TKI). We report that the derivatization of the marine alkaloid topoisomerase inhibitor lamellarin N provides a structurally new class of EGFR-TKIs. One of these, lamellarin 14, is effective against the C797S mutant EGFR. Bioinformatic analyses revealed that the derivatization transformed the topoisomerase inhibitor-like biological activity of lamellarin N into kinase inhibitor-like activity. Ba/F3 and PC-9 cells expressing the EGFR in-frame deletion within exon 19 (del ex19)/T790M/C797S triple-mutant were sensitive to lamellarin 14 in a dose range similar to the effective dose for cells expressing EGFR del ex19 or del ex19/T790M. Lamellarin 14 decreased the autophosphorylation of EGFR and the downstream signaling in the triple-mutant EGFR PC-9 cells. Furthermore, intraperitoneal administration of 10 mg/kg lamellarin 14 for 17 days suppressed tumor growth of the triple-mutant EGFR PC-9 cells in a mouse xenograft model using BALB/c nu/nu mice. Thus, lamellarin 14 serves as a novel structural backbone for an EGFR-TKI that prevents the development of cross-resistance against known drugs in this class.

A Potential Role of Adhesion Molecules on Lung Metastasis Enhanced by Local Inflammation.

BACKGROUND/AIM: Local and systemic inflammations are associated with negative long-term outcomes; however, their precise mechanism of action remains unclear. We previously demonstrated that hepatocyte growth factor (HGF)/c-Met signaling contributed to the enhancement of liver metastasis associated with peritonitis model. The aim of this study is to investigate the effect of local inflammation on the development of lung metastasis. MATERIALS AND METHODS: NL-17 cells were injected into BALB/c mice via the tail vein to produce a high potential model for lung metastasis. After injection of NL-17 cells, lipopolysaccharide (LPS) and live Pseudomonas aeruginosa, and phosphate-buffered saline were administered intratracheally to induce acute lung injury (ALI) and pneumonia, respectively. RESULTS: In both ALI and pneumonia mice, lung metastasis was significantly promoted compared to control mice. Concentrations of Interleukin-6, tumor necrosis factor-α, and HGF in the bronchoalveolar lavage fluid were significantly higher in ALI and pneumonia mice than in control mice. Neither administration of recombinant mouse HGF nor c-Met knockdown in NL-17 cells influenced the magnitude of lung metastasis. Yet stimulation with LPS increased the expression of α2 integrin, vascular cell-adhesion protein-1, and intercellular adhesion molecule-1 (ICAM-1) in the lung. Invasive activity of NL-17 cells was significantly up-regulated by LPS, but was suppressed by anti-ICAM-1 antibody. While LPS-stimulated NL-17 cells showed significantly promoted lung metastasis, E-selectin expression in the lungs of mice with ALI or pneumonia was significantly enhanced compared with control mice. CONCLUSION: Up-regulation of adhesion molecules, but not HGF/c-Met signaling, may contribute to the lung metastasis enhanced by local infection/inflammation.

A Potential Mechanism of Tumor Progression during Systemic Infections Via the Hepatocyte Growth Factor (HGF)/c-Met Signaling Pathway.

BACKGROUND: Increasing evidence has demonstrated that postoperative infectious complications (PICs) after digestive surgery are significantly associated with negative long-term outcomes; however, precise mechanisms of how PICs affect the poor long-term survival remain unclear. Here, we focused on the hepatocyte growth factor (HGF)/c-Met signaling pathway as one of those mechanisms. Methods: In the clinical setting, serum HGF levels were measured in the patients with sepsis and those with PICs after undergoing esophagectomy. Using a liver metastasis mouse model with cecal ligation and puncture (CLP), expressions of HGF and the roles of the HGF/c-Met pathway in the progression of tumor cells were examined. Results: Serum HGF levels were very high in the patients with intra-abdominal infection on postoperative days (PODs) 1, 3, and 5; similarly, compared to the patients without PICs, those with PICs had significantly higher serum HGF levels on 1, 3, and 5 days after esophagectomy. The patients with PICs showed poorer overall survival than those without PICs, and the patients with high serum HGF levels on POD 3 showed poorer prognosis than those with low HGF levels. Similarly, at 24 and 72 h after operation, serum levels of HGF in CLP mice were significantly higher than those in sham-operated mice. Intraperitoneal injection of mouse recombinant HGF significantly promoted liver metastases in sham-operated mice on 14 days after surgery. Knocking down c-Met expression on NL17 tumor cells by RNAi technology significantly inhibited the promotion of CLP-induced liver metastases. Conclusions: Infections after surgery increased serum HGF levels in the clinical as well as experimental settings. Induction of high serum HGF levels by CLP promoted liver metastases in a murine liver metastasis model, suggesting the involvement of the HGF/c-Met signaling pathway in tumor promotion mechanisms. Thus, targeting the HGF/c-Met signaling pathway may be a promising approach for malignant tumors, particularly in the patients with PICs.

Discovery of Inhibitors of Membrane Traffic from a Panel of Clinically Effective Anticancer Drugs.

In addition to their major targets, clinically effective drugs may have unknown off-targets. By identifying such off-targets it may be possible to repurpose approved drugs for new indications. We are interested in the Golgi apparatus as a novel target for cancer therapy, but there is a paucity of candidate Golgi-disrupting drugs. Here, we aimed to identify Golgi-disrupting compounds from a panel of 34 approved anticancer drugs by using HBC-4 human breast cancer cells and immunofluorescence microscopy to visualize the Golgi apparatus. The screen identified five drugs having Golgi-disrupting activity. Four of them were vinca alkaloids (vinorelbine, vindesine, vincristine and vinblastine), and the fifth drug was eribulin. This is the first study to demonstrate that vinorelbine, vindesine and eribulin possess Golgi-disrupting activity. The 5 drugs are known to inhibit tubulin polymerization and to induce microtubule depolymerization. Interestingly, a microtubule-stabilizer paclitaxel did not induce Golgi-disruption, suggesting that the three-dimensionally preserved microtubules are partly responsible for maintaining the Golgi complex. Concerning eribulin, a noteworthy drug because of its high clinical efficacy against advanced breast cancer, we further confirmed its Golgi-disrupting activity in 3 different human breast cancer cell lines, BSY-1, MDA-MB-231 and MCF-7. Golgi-disruption may contribute to anticancer efficacy of eribulin. In conclusion, the present study revealed that 4 vinca alkaloids and eribulin possessed potential Golgi-disrupting activity among a panel of 34 approved anticancer drugs. Other drugs covering various molecular-targeted drugs and classical DNA-damaging drugs showed no Golgi-disrupting effect. These results suggest that tubulin polymerization-inhibitors might be promising candidate drugs with Golgi-disrupting activity.

Antitumor profile of the PI3K inhibitor ZSTK474 in human sarcoma cell lines.

Treatment of patients with advanced sarcoma remains challenging due to lack of effective medicine, with the development of novel drugs being of keen interest. A pan-PI3K inhibitor, ZSTK474, has been evaluated in clinical trials against a range of advanced solid tumors, with clinical benefit shown in sarcoma patients. In the present study, we developed a panel of 14 human sarcoma cell lines and investigated the antitumor effect of 24 anticancer agents including ZSTK474, other PI3K inhibitors, and those clinically used for sarcoma treatment. ZSTK474 exhibited a similar antiproliferative profile to other PI3K inhibitors but was clearly different from the other drugs examined. Indeed, ZSTK474 inhibited PI3K-downstream pathways, in parallel to growth inhibition, in all cell lines examined, showing proof-of-concept of PI3K inhibition. In addition, ZSTK474 induced apoptosis selectively in Ewing's sarcoma (RD-ES and A673), alveolar rhabdomyosarcoma (SJCRH30) and synovial sarcoma (SYO-1, Aska-SS and Yamato-SS) cell lines, all of which harbor chromosomal translocation and resulting oncogenic fusion genes, EWSR1-FLI1, PAX3-FOXO1 and SS18-SSX, respectively. Finally, animal experiments confirmed the antitumor activity of ZSTK474 in vivo, with superior efficacy observed in translocation-positive cells. These results suggest that ZSTK474 could be a promising drug candidate for treating sarcomas, especially those harboring chromosomal translocation.

Cell-based chemical fingerprinting identifies telomeres and lamin A as modifiers of DNA damage response in cancer cells.

Telomere maintenance by telomerase activity supports the infinite growth of cancer cells. MST-312, a synthetic telomerase inhibitor, gradually shortens telomeres at non-acute lethal doses and eventually induces senescence and apoptosis of telomerase-positive cancer cells. Here we report that MST-312 at higher doses works as a dual inhibitor of telomerase and DNA topoisomerase II and exhibits acute anti-proliferative effects on cancer cells and xenografted tumours in vivo. Our cell-based chemical fingerprinting approach revealed that cancer cells with shorter telomeres and lower expression of lamin A, a nuclear architectural protein, exhibited higher sensitivity to the acute deleterious effects of MST-312, accompanied by formation of telomere dysfunction-induced foci and DNA double-strand breaks. Telomere elongation and lamin A overexpression attenuated telomeric and non-telomeric DNA damage, respectively, and both conferred resistance to apoptosis induced by MST-312 and other DNA damaging anticancer agents. These observations suggest that sufficient pools of telomeres and a nuclear lamina component contribute to the cellular robustness against DNA damage induced by therapeutic treatment in human cancer cells.

Targeting the Golgi apparatus to overcome acquired resistance of non-small cell lung cancer cells to EGFR tyrosine kinase inhibitors.

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (EGFR-TKIs) were demonstrated to provide survival benefit in patients with non-small cell lung cancer (NSCLC) harboring activating mutations of EGFR; however, emergence of acquired resistance to EGFR-TKIs has been shown to cause poor outcome. To overcome the TKI resistance, drugs with different mode of action are required. We previously reported that M-COPA (2-methylcoprophilinamide), a Golgi disruptor, suppressed the growth of gastric cancers overexpressing receptor tyrosine kinases (RTKs) such as hepatocyte growth factor receptor (MET) via downregulating their cell surface expression. In this study, we examined the antitumor effect of M-COPA on NSCLC cells with TKI resistance. As a result, M-COPA effectively downregulated cell surface EGFR and its downstream signals, and finally exerted in vivo antitumor effect in NSCLC cells harboring secondary (T790M/del19) and tertiary (C797S/T790M/del19) mutated EGFR, which exhibit acquired resistance to first- and third generation EGFR-TKIs, respectively. M-COPA also downregulated MET expression potentially involved in the acquired resistance to EGFR-TKIs via bypassing the EGFR pathway blockade. These results provide the first evidence that targeting the Golgi apparatus might be a promising therapeutic strategy to overcome the vicious cycle of TKI resistance in EGFR-mutated NSCLC cells via downregulating cell surface RTK expression.

TUFT1 interacts with RABGAP1 and regulates mTORC1 signaling.

The mammalian target of rapamycin (mTOR) pathway is commonly activated in human cancers. The activity of mTOR complex 1 (mTORC1) signaling is supported by the intracellular positioning of cellular compartments and vesicle trafficking, regulated by Rab GTPases. Here we showed that tuftelin 1 (TUFT1) was involved in the activation of mTORC1 through modulating the Rab GTPase-regulated process. TUFT1 promoted tumor growth and metastasis. Consistently, the expression of TUFT1 correlated with poor prognosis in lung, breast and gastric cancers. Mechanistically, TUFT1 physically interacted with RABGAP1, thereby modulating intracellular lysosomal positioning and vesicular trafficking, and promoted mTORC1 signaling. In addition, expression of TUFT1 predicted sensitivity to perifosine, an alkylphospholipid that alters the composition of lipid rafts. Perifosine treatment altered the positioning and trafficking of cellular compartments to inhibit mTORC1. Our observations indicate that TUFT1 is a key regulator of the mTORC1 pathway and suggest that it is a promising therapeutic target or a biomarker for tumor progression.

Family-wide Analysis of the Inhibition of Arf Guanine Nucleotide Exchange Factors with Small Molecules: Evidence of Unique Inhibitory Profiles.

Arf GTPases and their guanine nucleotide exchange factors (ArfGEFs) are major regulators of membrane traffic and organelle structure in cells. They are associated with a variety of diseases and are thus attractive therapeutic targets for inhibition by small molecules. Several inhibitors of unrelated chemical structures have been discovered, which have shown their potential in dissecting molecular pathways and blocking disease-related functions. However, their specificity across the ArfGEF family has remained elusive. Importantly, inhibitory responses in the context of membranes, which are critical determinants of Arf and ArfGEF cellular functions, have not been investigated. Here, we compare the efficiency and specificity of four structurally distinct ArfGEF inhibitors, Brefeldin A, SecinH3, M-COPA, and NAV-2729, toward six ArfGEFs (human ARNO, EFA6, BIG1, and BRAG2 and Legionella and Rickettsia RalF). Inhibition was assessed by fluorescence kinetics using pure proteins, and its modulation by membranes was determined with lipidated GTPases in the presence of liposomes. Our analysis shows that despite the intra-ArfGEF family resemblance, each inhibitor has a specific inhibitory profile. Notably, M-COPA is a potent pan-ArfGEF inhibitor, and NAV-2729 inhibits all GEFs, the strongest effects being against BRAG2 and Arf1. Furthermore, the presence of the membrane-binding domain in Legionella RalF reveals a strong inhibitory effect of BFA that is not measured on its GEF domain alone. This study demonstrates the value of family-wide assays with incorporation of membranes, and it should enable accurate dissection of Arf pathways by these inhibitors to best guide their use and development as therapeutic agents.

Targeting glioma stem cells in vivo by a G-quadruplex-stabilizing synthetic macrocyclic hexaoxazole.

G-quadruplex (G4) is a higher-order nucleic acid structure that is formed by guanine-rich sequences. G4 stabilization by small-molecule compounds called G4 ligands often causes cytotoxicity, although the potential medicinal impact of this effect has not been fully established. Here we demonstrate that a synthetic G4 ligand, Y2H2-6M(4)-oxazole telomestatin derivative (6OTD), limits the growth of intractable glioblastoma (grade IV glioma) and glioma stem cells (GSCs). Experiments involving a human cancer cell line panel and mouse xenografts revealed that 6OTD exhibits antitumor activity against glioblastoma. 6OTD inhibited the growth of GSCs more potently than it did the growth of differentiated non-stem glioma cells (NSGCs). 6OTD caused DNA damage, G1 cell cycle arrest, and apoptosis in GSCs but not in NSGCs. These DNA damage foci tended to colocalize with telomeres, which contain repetitive G4-forming sequences. Compared with temozolomide, a clinical DNA-alkylating agent against glioma, 6OTD required lower concentrations to exert anti-cancer effects and preferentially affected GSCs and telomeres. 6OTD suppressed the intracranial growth of GSC-derived tumors in a mouse xenograft model. These observations indicate that 6OTD targets GSCs through G4 stabilization and promotion of DNA damage responses. Therefore, G4s are promising therapeutic targets for glioblastoma.

Synthesis and biological evaluation of novel FK228 analogues as potential isoform selective HDAC inhibitors.

Novel C4- and C7-modified FK228 analogues were efficiently synthesized in a highly convergent and unified manner. This synthesis features the amide condensation of glycine-d-cysteine-containing segments with d-valine-containing segments for the direct assembly of the corresponding seco-acids, which are key precursors of macrolactones. The HDAC inhibition assay and cell-growth inhibition analysis of the synthesized analogues revealed novel aspects of their structure-activity relationship. This study demonstrated that simple modification at the C4 and C7 side chains in FK228 is effective for improving both HDAC inhibitory activity and isoform selectivity; moreover, potent and highly isoform-selective class I HDAC1 inhibitors were identified.

M-COPA, a novel Golgi system disruptor, suppresses apoptosis induced by Shiga toxin.

Shiga toxin (Stx) is a main virulence factor of Stx-producing Escherichia coli (STEC) that contributes to diarrhea and hemorrhagic colitis and occasionally to fatal systemic complications. Therefore, the development of an antidote to neutralize Stx toxicity is urgently needed. After internalization into cells, Stx is transferred to the Golgi apparatus via a retrograde vesicular transport system. We report here that 2-methylcoprophilinamide (M-COPA), a compound that induces disassembly of the Golgi apparatus by inactivating ADP-ribosylation factor 1 (Arf1), suppresses Stx-induced apoptosis. M-COPA inhibited transport of Stx from the plasma membrane to the Golgi apparatus and suppressed degradation of anti-apoptotic proteins and the activation of caspases. These findings suggest that inhibition of Stx retrograde transport by M-COPA could be a novel approach to suppress Stx toxicity.

M-COPA, a Golgi Disruptor, Inhibits Cell Surface Expression of MET Protein and Exhibits Antitumor Activity against MET-Addicted Gastric Cancers.

The Golgi apparatus is responsible for transporting, processing, and sorting numerous proteins in the cell, including cell surface-expressed receptor tyrosine kinases (RTK). The small-molecule compound M-COPA [2-methylcoprophilinamide (AMF-26)] disrupts the Golgi apparatus by inhibiting the activation of Arf1, resulting in suppression of tumor growth. Here, we report an evaluation of M-COPA activity against RTK-addicted cancers, focusing specifically on human gastric cancer (GC) cells with or without MET amplification. As expected, the MET-addicted cell line MKN45 exhibited a better response to M-COPA than cell lines without MET amplification. Upon M-COPA treatment, cell surface expression of MET was downregulated with a concurrent accumulation of its precursor form. M-COPA also reduced levels of the phosphorylated form of MET along with the downstream signaling molecules Akt and S6. Similar results were obtained in additional GC cell lines with amplification of MET or the FGF receptor FGFR2 MKN45 murine xenograft experiments demonstrated the antitumor activity of M-COPA in vivo Taken together, our results offer an initial preclinical proof of concept for the use of M-COPA as a candidate treatment option for MET-addicted GC, with broader implications for targeting the Golgi apparatus as a novel cancer therapeutic approach. Cancer Res; 76(13); 3895-903. ©2016 AACR.

Identification of Cyproheptadine as an Inhibitor of SET Domain Containing Lysine Methyltransferase 7/9 (Set7/9) That Regulates Estrogen-Dependent Transcription.

SET domain containing lysine methyltransferase 7/9 (Set7/9), a histone lysine methyltransferase (HMT), also methylates non-histone proteins including estrogen receptor (ER) α. ERα methylation by Set7/9 stabilizes ERα and activates its transcriptional activities, which are involved in the carcinogenesis of breast cancer. We identified cyproheptadine, a clinically approved antiallergy drug, as a Set7/9 inhibitor in a high-throughput screen using a fluorogenic substrate-based HMT assay. Kinetic and X-ray crystallographic analyses revealed that cyproheptadine binds in the substrate-binding pocket of Set7/9 and inhibits its enzymatic activity by competing with the methyl group acceptor. Treatment of human breast cancer cells (MCF7 cells) with cyproheptadine decreased the expression and transcriptional activity of ERα, thereby inhibiting estrogen-dependent cell growth. Our findings suggest that cyproheptadine can be repurposed for breast cancer treatment or used as a starting point for the discovery of an anti-hormone breast cancer drug through lead optimization.

A novel thiophene-3-carboxamide analog of annonaceous acetogenin exhibits antitumor activity via inhibition of mitochondrial complex I.

Previously we synthesized JCI-20679, a novel thiophene-3-carboxamide analog of annonaceous acetogenins which have shown potent antitumor activity, with no serious side effects, in mouse xenograft models. In this study, we investigated the antitumor mechanism of JCI-20679. The growth inhibition profile (termed "fingerprint") of this agent across a panel of 39 human cancer cell lines (termed "JFCR39") was measured; this fingerprint was analyzed by the COMPARE algorithm utilizing the entire drug sensitivity database for the JFCR39 panel. The JCI-20679-specific fingerprint exhibited a high similarity to those of two antidiabetic biguanides and a natural rotenoid deguelin which were already known to be mitochondrial complex I inhibitors. In addition, the fingerprint exhibited by JCI-20679 was not similar to that displayed by any typical anticancer drugs within the database, suggesting that it has a unique mode of action. In vitro experiments using bovine heart-derived mitochondria showed direct inhibition of mitochondrial complex I by JCI-20679 and associated derivatives. This inhibition of enzymatic activity positively correlated with tumor cell growth inhibition. Furthermore, a fluorescently labeled derivative of JCI-20679 localized to the mitochondria of live cancer cells in vitro. These results suggest that JCI-20679 can inhibit cancer cell growth by inhibiting mitochondrial complex I. Our results show that JCI-20679 is a novel anticancer drug lead with a unique mode of action.

Pyrrocidine A, a metabolite of endophytic fungi, has a potent apoptosis-inducing activity against HL60 cells through caspase activation via the Michael addition.

Pyrrocidine A is a known antimicrobial compound produced by endophytic fungi and has a unique 13-membered macrocyclic alkaloid structure with an α,ß-unsaturated carbonyl group. We have previously reported that pyrrocidine A shows potent cytotoxicity against human acute promyelocytic leukemia HL60 cells, and the activity is 70-fold higher than that of pyrrocidine B which is the analog lacking the α,ß-unsaturated carbonyl group. Pyrrocidine A induced nuclear condensation, DNA fragmentation and caspase activation in HL60 cells. Since the DNA fragmentation was suppressed by pretreatment with the pan-caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp (OMe) fluoromethylketone (z-VAD-fmk), caspase-mediated apoptosis contributes to pyrrocidine A-induced cytotoxicity. JFCR39 human cancer cells panel indicated that the mechanism of action of pyrrocidine A is different from other clinical anticancer drugs, and this compound broadly inhibited the growth of various cancer cell lines. The apoptosis induction by pyrrocidine A was suppressed by both N-acetyl-l-cysteine (NAC) and glutathione, both of which are thiol-containing antioxidants. Furthermore, pyrrocidine A directly bound to N-acetyl-l-cysteine methyl ester (NACM) through the Michael-type addition at the α,ß-unsaturated carbonyl group and was detected by HPLC and liquid chromatography-ESI-tandem MS (LC-ESI-MS/MS) analyses. This indicates that this moiety is crucial for the potent apoptosis-inducing activity of pyrrocidine A.

Abdominal Infection Suppresses the Number and Activity of Intrahepatic Natural Killer Cells and Promotes Tumor Growth in a Murine Liver Metastasis Model.

BACKGROUND: Increasing evidence suggests that postoperative infection is associated with poorer long-term outcome in various malignancies. However, the mechanism of poor prognosis induced by postoperative infection has not been clearly explained. We sought to determine whether abdominal infection promotes cancer metastases in a murine liver metastasis model, and to investigate the role of liver natural killer (NK) cells on antitumor immunity during abdominal infection. METHODS: Female BALB/c (8-10 weeks old) mice were inoculated with NL-17 colon cancer cells into the spleen and then subjected to abdominal infection induced by cecal ligation and puncture (CLP) or sham treatment. The extent of liver metastases and cytokine production in the serum and liver were investigated. Cell fraction and cytotoxic activities of liver mononuclear cells (MNCs) were elucidated. RESULTS: CLP mice had poorer survival and their serum levels of IL-6, -10, and -12p70 were significantly elevated on day 1 compared with sham-treated and control mice. No obvious differences in cytokine levels of the liver homogenates were identified among the three groups, except IL-12p70 levels in CLP mice on day 7 significantly decreased. The cytotoxic activities of liver MNCs were significantly suppressed in CLP mice soon after tumor inoculation. Flow cytometry revealed a decrease in NK cells in the liver and perforin and granzyme B expression levels. CONCLUSIONS: Abdominal infection promoted liver metastases in a murine liver metastasis model, which may be partially caused by a decrease in the number and activity of NK cells during abdominal infection.

Identification of a molecular target of kurahyne, an apoptosis-inducing lipopeptide from marine cyanobacterial assemblages.

In 2014, we isolated kurahyne, an acetylene-containing lipopeptide, from a marine cyanobacterial assemblage of Lyngbya sp. Kurahyne exhibited growth-inhibitory activity against human cancer cells, and induced apoptosis in HeLa cells. However, its mode of action is not yet clear. To elucidate its mode of action, we carried out several cell-based assays, and identified the intracellular target molecule of kurahyne as sarco/endoplasmic reticulum Ca(2+) ATPase (SERCA). In addition, we found that kurahyne inhibited the differentiation of macrophages into osteoclasts.