Tomohisa Yokoyama

Roles of the Akt/mTOR/p70S6K and ERK1/2 signaling pathways in curcumin-induced autophagy.

Curcumin has a potent anticancer effect and is a promising new therapeutic strategy. We previously demonstrated that curcumin induced non-apoptotic autophagic cell death in malignant glioma cells in vitro and in vivo. This compound inhibited the Akt/mammalian target of rapamycin/p70 ribosomal protein S6 kinase pathway and activated the extracellular signal-regulated kinases 1/2 thereby inducing autophagy. Interestingly, activation of the first pathway inhibited curcumin-induced autophagy and cytotoxicity, whereas inhibition of the latter pathway inhibited curcumin-induced autophagy and induced apoptosis, thus augmenting the cytotoxicity of curcumin. These results imply that these two autophagic pathways have opposite effects on curcumin’s cytotoxicity. However, inhibition of nuclear factor κB, which is the main target of curcumin for its anticancer effect, was not observed in malignant glioma cells. These results suggest that autophagy but not nuclear factor κB plays a central role in curcumin anticancer therapy and warrant further investigation toward application in patients with malignant gliomas. Here, we discuss the therapeutic role of two autophagic pathways influenced by curcumin. Addendum to: Evidence That Curcumin Suppresses the Growth of Malignant Gliomas in Vitro and in Vivo through Induction of Autophagy: Role of Akt and Extracellular Signal-Regulated Kinase Signaling Pathways H. Aoki, Y. Takada, S. Kondo, R. Sawaya, B. B. Aggarwal and Y. Kondo Mol Pharmacol 2007; 72:29-39

Monitoring autophagy in glioblastoma with antibody against isoform B of human microtubule-associated protein 1 light chain 3

Autophagy, an evolutionarily conserved response to stress, has recently been implicated in cancer initiation and progression, but the detailed mechanisms and functions have not yet been fully elucidated. One major obstacle to our understanding is lack of an efficient and robust method to specifically monitor autophagic cells in cancer specimens. To identify molecular events associated with autophagy, we performed cDNA microarray analysis of autophagic glioblastoma cell lines. Based on the analysis, we raised a polyclonal antibody against isoform B of human microtubule-associated protein 1 light chain 3 (LC3B). Application of the anti-LC3B antibody revealed the presence of autophagic cells in both in vitro and in vivo settings. Of the 65 glioblastoma tissues, 31 had highly positive cytoplasmic staining of LC3B. The statistical interaction between cytoplasmic staining of LC3B and Karnofsky Performance Scale score was significant. High expression of LC3B was associated with an improved outcome for patients with poorer performance, whereas, for patients with normal performance, survival was better for patients with low staining than with high staining of LC3B. Anti-LC3B antibody provides a useful tool for monitoring the induction of autophagy in cancer cells and tissues.

Pivotal Role of the Cyclin-dependent Kinase Inhibitor p21WAF1/CIP1 in Apoptosis and Autophagy

Programmed cell death (PCD) is involved in a variety of biologic events. Based on the morphologic appearance of the cells, there are two types of PCD as follows: apoptotic (type I) and autophagic (type II). However, the molecular machinery that determines the type of PCD is poorly defined. The purpose of this study was to show whether the presence of the cyclin-dependent kinase (CDK) inhibitor p21WAF1/CIP1, a modulator of apoptosis, determines which type of PCD the cell undergoes. Treatment with C2-ceramide was associated with both the cleavage of caspase-3 and poly(ADP-ribose) polymerase and the degradation of autophagy-related Beclin 1 and Atg5 proteins, without a change in the cyclin-CDK activity, which culminated in apoptosis in p21+/+ mouse embryonic fibroblasts (MEFs). On the other hand, C2-ceramide did not cleave caspase-3 or poly(ADP-ribose) polymerase and kept Beclin 1 and Atg5 proteins stable in p21-/- MEFs, events that this time culminated in autophagy. When expression of the p21 protein was inhibited by small interfering RNA or when the overexpression of Beclin 1 or Atg5 was induced, autophagy rather than apoptosis was initiated in the p21+/+ MEFs treated with C2-ceramide. In contrast, the exogenous expression of p21 or the silencing of Beclin 1 and Atg5 with small interfering RNA increased the number of apoptotic cells and decreased the number of autophagic cells among C2-ceramide-treated p21-/- MEFs. γ-Irradiation, which endogenously generates ceramide, induced a similar tendency in these MEFs. These results suggest that p21 plays an essential role in determining the type of cell death, positively for apoptosis and negatively for autophagy.

Vitamin K2 induces autophagy and apoptosis simultaneously in leukemia cells

Vitamin K2 (menaquinone-4: VK2) is a potent inducer for apoptosis in leukemia cells in vitro. HL-60bcl-2 cells, which are derived from a stable transfectant clone of the human bcl-2 gene into the HL-60 leukemia cell line, show 5-fold greater expression of the Bcl-2 protein compared with HL-60neo cells, a control clone transfected with vector alone. VK2 induces apoptosis in HL-60neo cells, whereas HL-60bcl-2 cells are resistant to apoptosis induction by VK2 but show inhibition of cell growth along with an increase of cytoplasmic vacuoles during exposure to VK2. Electron microscopy revealed formation of autophagosomes and autolysosomes in HL-60bcl-2 cells after exposure to VK2. An increase of acid vesicular organelles (AVOs) detected by acridine orange staining for lysosomes as well as conversion of LC3B-I into LC3B-II by immunonoblotting and an increased punctuated pattern of cytoplasmic LC3B by fluorescent immunostaining all supported induction of enhanced autophagy in response to VK2 in HL-60bcl-2 cells. However, during shorter exposure to VK2, the formation of autophagosomes was also prominent in HL-60neo cells although nuclear chromatin condensations and nuclear fragments were also observed at the same time. These findings indicated the mixed morphologic features of apoptosis and autophagy. Inhibition of autophagy by either addition of 3-methyladenine, siRNA for Atg7, or Tet-off Atg5 system all resulted in attenuation of VK2-incuded cell death, indicating autophagy-mediated cell death in response to VK2. These data demonstrate that autophagy and apoptosis can be simultaneously induced by VK2. However, autophagy becomes prominent when the cells are protected from rapid apoptotic death by a high expression level of Bcl-2.

Diagnostic Peroral Video Cholangioscopy Is an Accurate Diagnostic Tool for Patients With Bile Duct Lesions

BACKGROUND & AIMS We evaluated the diagnostic ability of a newly developed peroral video cholangioscopy (PVCS) in patients with pancreaticobiliary disorders. METHODS We retrospectively evaluated data from 144 patients with pancreaticobiliary disorders, collected from 5 tertiary referral centers. Endoscopic sphincterotomy (EST) or endoscopic papillary balloon dilation (EPBD) was performed before PVCS. We performed 2 types of PVCS, using a conventional therapeutic duodenoscope. If tissue samples were needed, cholangioscopy-assisted biopsy or fluoroscopy-guided biopsy was performed. RESULTS PVCS was advanced into the bile duct in all cases after patients received EST (n = 134 cases), EPBD (n = 2), a combination of EST and EPBD (n = 1), or without treatment of the major papilla (n = 7). Biopsy samples were collected successfully from 112 of 120 cases in which endoscopists considered tissue sampling necessary. Endoscopic retrograde cholangiopancreatography (ERCP)/biopsy correctly identified 83 of 96 malignant lesions and 19 of 24 benign lesions (accuracy = 85.0%; sensitivity = 86.5%; specificity = 79.2%; positive predictive value = 94.3%; negative predictive value = 59.4%). Endoscopic retrograde cholangiopancreatography (ERCP)/biopsy plus PVCS correctly identified 95 of 96 malignant lesions and 23 of 24 benign lesions (accuracy = 98.3%; sensitivity = 99.0%; specificity = 95.8%; positive predictive value = 99.0%; negative predictive value = 95.8%). Procedure-related complications included pancreatitis (4 cases, 2.8%) and cholangitis (6 cases, 4.3%). CONCLUSIONS PVCS is an accurate diagnostic tool for patients with pancreaticobiliary disorders; resolution was well-defined when combined with biopsy analysis. Prospective multicenter clinical trials should evaluate the clinical utility of PVCS in diagnosis of biliary tract diseases.

Combined treatment with SAHA, bortezomib, and clarithromycin for concomitant targeting of aggresome formation and intracellular proteolytic pathways enhances ER stress-mediated cell death in breast cancer cells.

The ubiquitin-proteasome pathway and the autophagy-lysosome pathway are two major intracellular protein degradation systems. We previously reported that clarithromycin (CAM) blocks autophagy flux, and that combined treatment with CAM and proteasome inhibitor bortezomib (BZ) enhances ER-stress-mediated apoptosis in breast cancer cells, whereas treatment with CAM alone results in almost no cytotoxicity. Since HDAC6 is involved in aggresome formation, which is recognized as a cytoprotective response serving to sequester misfolded proteins and facilitate their clearance by autophagy, we further investigated the combined effect of vorinostat (suberoylanilide hydroxamic acid (SAHA)), which has a potent inhibitory effect for HDAC6, with CAM and BZ in breast cancer cell lines. SAHA exhibited some cytotoxicity along with an increased acetylation level of α-tubulin, a substrate of HDAC6. Combined treatment of SAHA, CAM, and BZ potently enhanced the apoptosis-inducing effect compared with treatment using each reagent alone or a combination of two of the three. Expression levels of ER-stress-related genes, including the pro-apoptotic transcription factor CHOP (GADD153), were maximally induced by the simultaneous combination of three reagents. Like breast cancer cell lines, a wild-type murine embryonic fibroblast (MEF) cell line exhibited enhanced cytotoxicity and maximally up-regulated Chop after combined treatment with SAHA, CAM, and BZ; however, a Chop knockout MEF cell line almost completely canceled this enhanced effect. The specific HDAC6 inhibitor tubacin also exhibited a pronounced cytocidal effect with a combination of CAM plus BZ. These data suggest that simultaneous targeting of intracellular proteolytic pathways and HDAC6 enhances ER-stress-mediated apoptosis in breast cancer cells.

EGFR-independent autophagy induction with gefitinib and enhancement of its cytotoxic effect by targeting autophagy with clarithromycin in non-small cell lung cancer cells.

Gefitinib (GEF), an inhibitor for EGFR tyrosine kinase, potently induces autophagy in non-small cell lung cancer (NSCLC) cell lines such as PC-9 cells expressing constitutively activated EGFR kinase by EGFR gene mutation as well as A549 and H226 cells with wild-type EGFR. Unexpectedly, GEF-induced autophagy was also observed in non-NSCLC cells such as murine embryonic fibroblasts (MEF) and leukemia cell lines K562 and HL-60 without EGFR expression. Knockout of EGFR gene in A549 cells by CRISPR/Cas9 system still exhibited autophagy induction after treatment with GEF, indicating that the autophagy induction by GEF is not mediated through inhibiting EGFR kinase activity. Combined treatment with GEF and clarithromycin (CAM), a macrolide antibiotic having the effect of inhibiting autophagy flux, enhances the cytotoxic effect in NSCLC cell lines, although treatment with CAM alone exhibits no cytotoxicity. GEF treatment induced up-regulation of endoplasmic reticulum (ER)-stress related genes such as CHOP/GADD153 and GRP78. Knockdown of CHOP in PC-9 cells and Chop-knockout MEF both exhibited less sensitivity to GEF than controls. Addition of CAM in culture medium resulted in further pronounced GEF-induced ER stress loading, while CAM alone exhibited no effect. These data suggest that GEF-induced autophagy functions as cytoprotective and indicates the potential therapeutic possibility of using CAM for GEF therapy. Furthermore, it is suggested that the intracellular signaling for autophagy initiation in response to GEF can be completely dissociated from EGFR, but unknown target molecule(s) of GEF for autophagy induction might exist.

Macrolides sensitize EGFR-TKI-induced non-apoptotic cell death via blocking autophagy flux in pancreatic cancer cell lines.

Pancreatic cancer is one of the most difficult types of cancer to treat because of its high mortality rate due to chemotherapy resistance. We previously reported that combined treatment with gefitinib (GEF) and clarithromycin (CAM) results in enhanced cytotoxicity of GEF along with endoplasmic reticulum (ER) stress loading in non-small cell lung cancer cell lines. An epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) such as GEF induces autophagy in a pro-survival role, whereas CAM inhibits autophagy flux in various cell lines. Pronounced GEF-induced cytotoxicity therefore appears to depend on the efficacy of autophagy inhibition. In the present study, we compared the effect on autophagy inhibition among such macrolides as CAM, azithromycin (AZM), and EM900, a novel 12-membered non-antibiotic macrolide. We then assessed the enhanced GEF-induced cytotoxic effect on pancreatic cancer cell lines BxPC-3 and PANC-1. Autophagy flux analysis indicated that AZM is the most effective autophagy inhibitor of the three macrolides. CAM exhibits an inhibitory effect but less than AZM and EM900. Notably, the enhancing effect of GEF-induced cytotoxicity by combining macrolides correlated well with their efficient autophagy inhibition. However, this pronounced cytotoxicity was not due to upregulation of apoptosis induction, but was at least partially mediated through necroptosis. Our data suggest the possibility of using macrolides as ‘chemosensitizers’ for EGFR-TKI therapy in pancreatic cancer patients to enhance non-apoptotic tumor cell death induction.

腸管穿孔を契機に診断に至ったメトトレキサート関連リンパ増殖性疾患（methotrexate-associated lymphoproliferative disorder：MTX-LPD）

A 70-year-old woman was diagnosed with chronic rheumatoid arthritis and treated with methotrexate and prednisolone. She visited our hospital to determine the cause of her continuous fatigue and fever for the past three weeks. She consumed no food orally and was provided antibiotics because free air was found on computed tomography (CT). Intraperitoneal small lymphadenopathy and swelling of both adrenal glands was also found on CT, and MTX-associated lymphoproliferative disorder (MTX-LPD) was suspected. Am adrenal gland biopsy showed diffuse large B-cell lymphoma (DLBCL) associated with MTX-LPD. The causes of gastrointestinal perforation with collagen diseases have been reported to be functional gastrointestinal disorders with collagen diseases like amyloidosis, gastrointestinal infections in immunocompromised patients, and side effects of medication, such as steroids or NSAIDs and MTX. MTX-LPD is an uncommon side effect of methotrexate. To ensure its appropriate diagnosis and treatment, it is important to improve the degree of recognition of MTX-LPD, and a prompt response is needed.

Totally implantable central venous device-associated blood stream infection in elderly malignant disease patients

AIM We investigated the rate of bloodstream infections in elderly malignant disease patients whose totally implantable central venous device (CV ports) had been removed for any reason at our hospital. METHODS We evaluated 22 elderly malignant disease patients who had had their CV ports removed for any reason between May 2014 to April 2015. RESULTS The patients were 12 males and 10 females between 62 and 86 years of age with a median age of 75.5 years. The catheter tip cultures were positive in 6 out of 22 cases (27.3%). Gram-positive cocci were detected in 5 cases, and gram-positive bacilli were detected in 1 case. Five of these 6 cases (83%) found to have positive catheter tip cultures were cultured at the time of death. In addition, 5 of the 13 catheters removed at the time of death resulted in positive culture results (38%). The positive culture ratio correlated well with the ratio of death and the age in cases of hematopoietic tumors. CONCLUSION In cancer patients, the CV port is frequently used for the delivery of anti-cancer medicines. However, CV port infections are underestimated and typically not recognized in a timely manner. Patients suspected of having a CV port infection should be closely observed and the catheter removed immediately. However, it is very difficult to decide to discontinue a CV port, since its removal may render patients more susceptible to blood stream infections due to their poor general health and old age. CV port use should be considered in such cases to prevent future blood stream infections.