Showing papers by "Susumu Kobayashi published in 2007"
TL;DR: Evidence is provided that BIM is involved in TKI- induced apoptosis in sensitive EGFR-mutant cells and that both attenuation of the up-regulation of BIM and resistance to gefitinib-induced apoptosis are seen in models that contain the common EGFR T790M and the novel L747S secondary resistance mutations.
Abstract: Background Epidermal growth factor receptor (EGFR) mutations are present in the majority of patients with non-small cell lung cancer (NSCLC) responsive to the EGFR tyrosine kinase inhibitors (TKIs) gefitinib or erlotinib. These EGFR-dependent tumors eventually become TKI resistant, and the common secondary T790M mutation accounts for half the tumors with acquired resistance to gefitinib. However, the key proapoptotic proteins involved in TKI-induced cell death and other secondary mutations involved in resistance remain unclear. The objective of this study was to identify the mechanism of EGFR TKI-induced apoptosis and secondary resistant mutations that affect this process. Methods and Findings To study TKI-induced cell death and mechanisms of resistance, we used lung cancer cell lines (with or without EGFR mutations), Ba/F3 cells stably transfected with EGFR mutation constructs, and tumor samples from a gefitinib-resistant patient. Here we show that up-regulation of the BH3-only polypeptide BIM (also known as BCL2-like 11) correlated with gefitinib-induced apoptosis in gefitinib-sensitive EGFR-mutant lung cancer cells. The T790M mutation blocked gefitinib-induced up-regulation of BIM and apoptosis. This blockade was overcome by the irreversible TKI CL-387,785. Knockdown of BIM by small interfering RNA was able to attenuate apoptosis induced by EGFR TKIs. Furthermore, from a gefitinib-resistant patient carrying the activating L858R mutation, we identified a novel secondary resistant mutation, L747S in cis to the activating mutation, which attenuated the up-regulation of BIM and reduced apoptosis. Conclusions Our results provide evidence that BIM is involved in TKI-induced apoptosis in sensitive EGFRmutant cells and that both attenuation of the up-regulation of BIM and resistance to gefitinibinduced apoptosis are seen in models that contain the common EGFR T790M and the novel L747S secondary resistance mutations. These findings also suggest that induction of BIM may have a role in the treatment of TKI-resistant tumors.
464 citations
TL;DR: Gefitinib monotherapy leads to objective responses in most patients with EGFR mutations and small molecule TKIs are the new treatment paradigm for EGFR-mutant NSCLC.
164 citations
TL;DR: A SNP within a distal enhancer that is associated with a subtype of leukemia and exerts a deleterious effect through remote transcriptional dysregulation in specific progenitor subtypes is identified.
Abstract: Targeted disruption of a highly conserved distal enhancer reduces expression of the PU.1 transcription factor by 80% and leads to acute myeloid leukemia (AML) with frequent cytogenetic aberrations in mice. Here we identify a SNP within this element in humans that is more frequent in AML with a complex karyotype, leads to decreased enhancer activity, and reduces PU.1 expression in myeloid progenitors in a development-dependent manner. This SNP inhibits binding of the chromatin-remodeling transcriptional regulator special AT-rich sequence binding protein 1 (SATB1). Overexpression of SATB1 increased PU.1 expression, and siRNA inhibition of SATB1 downregulated PU.1 expression. Targeted disruption of the distal enhancer led to a loss of regulation of PU.1 by SATB1. Interestingly, disruption of SATB1 in mice led to a selective decrease of PU.1 RNA in specific progenitor types (granulocyte-macrophage and megakaryocyte-erythrocyte progenitors) and a similar effect was observed in AML samples harboring this SNP. Thus we have identified a SNP within a distal enhancer that is associated with a subtype of leukemia and exerts a deleterious effect through remote transcriptional dysregulation in specific progenitor subtypes.
123 citations
TL;DR: Two anti-mycobacterial peptides with a lasso structure, named lariatins A and B, were separated by HP-20 and ODS column chromatographies and purified by HPLC from the culture broth of Rhodococcus jostii K01-B0171, which was isolated from soil aggregates collected in Yunnan, China.
Abstract: Lariatins, Novel Anti-mycobacterial Peptides with a Lasso Structure, Produced by Rhodococcus jostii K01-B0171
73 citations
TL;DR: The inclusion of CDDO in the therapy of AML characterized by dysfunctional CEBPA expression is suggested, because AML is characterized by arrested differentiation.
66 citations
TL;DR: Novel mutations mediating resistance to irreversible EGFR inhibitors are identified and alternative strategies to overcome or prevent the development of resistance in EGFR-mutant non-small cell lung cancers are revealed.
Abstract: Patients with epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer derive significant clinical benefit from treatment with the EGFR tyrosine kinase inhibitors gefitinib and erlotinib. Secondary EGFR mutations such as EGFR T790M commonly lead to resistance to these agents, limiting their long-term efficacy. Irreversible EGFR inhibitors such as CL-387,785 can overcome resistance and are in clinical development, yet acquired resistance against these agents is anticipated. We carried out a cell-based, in vitro random mutagenesis screen to identify EGFR mutations that confer resistance to CL-387,785 using T790M-mutant H1975 lung adenocarcinoma cells. Mutations at several residues occurred repeatedly leading to functional resistance to CL-387,785. These variants showed uninhibited cell growth, reduced apoptosis, and persistent EGFR activation in the presence of CL-387,785 as compared with parental H1975 cells, thus confirming their role in resistance. A screen of alternative agents showed that both an alternative EGFR inhibitor and a cyclin-dependent kinase 4 inhibitor led to significant inhibition of cell growth of the resistant mutants, suggestive of potential alternative treatment strategies. These results identify novel mutations mediating resistance to irreversible EGFR inhibitors and reveal alternative strategies to overcome or prevent the development of resistance in EGFR-mutant non-small cell lung cancers.
65 citations
TL;DR: Carba derivatives of cPA, in which the phosphate oxygen was replaced with a methylene group at either the sn-2 or thesn-3 position, showed much more potent inhibitory effects on MM1 tumor cell transcellular migration and the pulmonary metastasis of B16-F0 melanoma than the natural pal-cPA.
62 citations
TL;DR: A convergent total synthesis of khafrefungin was accomplished on the basis of the highly stereoselective TiCl4-mediated vinylogous Mukaiyama aldol reaction using vinylketene silyl N,O-acetal and syn-selective aldl reaction of enal 5a and ethyl ketone 6 followed by anti-dehydration under Mitsunobu conditions.
50 citations
TL;DR: In this article, total synthesisation of (±)-debromoflustramine B and E and (±)debromophromide B were accomplished using a common and versatile intermediate spirocyclic oxindole 14, which was concisely prepared through intramolecular Ullmann coupling and Claisen rearrangement from iodoindole 13 on a multigram scale.
41 citations
TL;DR: Results suggest that neoechinulin A endows the cells with cytoprotection through a biological effect different from the apparent antioxidant/anti-nitration activities.
Abstract: Neoechinulin A, an alkaloid from Eurotium rubrum Hiji025, protected neuronal PC12 cells against cell death induced by peroxynitrite derived from SIN-1 (3-(4-morpholinyl)sydnonimine hydrochloride). In this study, we investigated the structure-activity relationships of neoechinulin A and a set of its analogues by using assays to measure anti-nitration and antioxidant activities and cytoprotection against SIN-1-induced PC12 cell death. The presence of the diketopiperazine ring was essential for both the antioxidant and anti-nitration activities of neoechinulin A derivatives. Nevertheless, a derivative lacking the diketopiperazine ring could still protect PC12 cells against SIN-1 cytotoxicity. An acyclic analogue completely lost the cytoprotective effect while retaining its antioxidant/anti-nitration activities. Pre-incubation of the cells with neoechinulin A for at least 12 hours was essential for the cells to gain SIN-1 resistance. These results suggest that neoechinulin A endows the cells with cytoprotection through a biological effect different from the apparent antioxidant/anti-nitration activities.
40 citations
TL;DR: It is concluded that DCs fused after stimulation by OK-432 may have the potential applicability to the field of antitumor immunotherapy and may provide a platform for adoptive immunotherapy in the clinical setting.
Abstract: Dendritic/tumor fusion cell (FC) vaccine is an effective approach for various types of cancer but has not yet been standardized. Antitumor activity can be modulated by different mechanisms such as dendritic cell (DC) maturation state. This study addressed optimal strategies for FC preparations to enhance Ag-specific CTL activity. We have created three types of FC preparations by alternating fusion cell partners: 1) immature DCs fused with autologous colorectal carcinoma cells (Imm-FCs); 2) Imm-FCs followed by stimulation with penicillin-inactivated Streptococcus pyogenes (OK-432) (Imm-FCs/OK); and 3) OK-432-stimulated DCs directly fused to autologous colorectal carcinoma cells (OK-FCs). Both OK-FCs and Imm-FCs/OK coexpressed the CEA, MUC1, and significantly higher levels of CD86, CD83, and IL-12 than those obtained with Imm-FCs. Short-term culture of fusion cell preparations promoted the fusion efficiency. Interestingly, OK-FCs were more efficient in stimulating CD4(+) and CD8(+) T cells capable of high levels of IFN-gamma production and cytolysis of autologous tumor or semiallogeneic targets. Moreover, OK-FCs are more effective inducer of CTL activation compared with Imm-FCs/OK on a per fusion cell basis. The pentameric assay confirmed that CEA- and MUC1-specific CTL was induced simultaneously by OK-FCs at high frequency. Furthermore, the cryopreserved OK-FCs retained stimulatory capacity for inducing antitumor immunity. These results suggest that OK-432 promotes fusion efficiency and induction of Ag-specific CTL by fusion cells. We conclude that DCs fused after stimulation by OK-432 may have the potential applicability to the field of antitumor immunotherapy and may provide a platform for adoptive immunotherapy in the clinical setting.
TL;DR: The results strongly suggest that synergism between OK-DCs and heat-treated tumor cells enhances the immunogenicity of FCs and provides a promising means of inducing therapeutic antitumor immunity.
Abstract: Dendritic cell (DC)/tumor cell fusion cells (FCs) can induce potent CTL responses. The therapeutic efficacy of a vaccine requires the improved immunogenicity of both DCs and tumor cells. The DCs stimulated with the TLR agonist penicillin-killed Streptococcus pyogenes (OK-432; OK-DCs) showed higher expression levels of MHC class I and II, CD80, CD86, CD83, IL-12, and heat shock proteins (HSPs) than did immature DCs. Moreover, heat-treated autologous tumor cells displayed a characteristic phenotype with increased expression of HSPs, carcinoembryonic Ag (CEA), MUC1, and MHC class I (HLA-A2 and/or A24). In this study, we have created four types of FC preparation by alternating fusion cell partners: 1) immature DCs fused with unheated tumor cells; 2) immature DCs fused with heat-treated tumor cells; 3) OK-DCs fused with unheated tumor cells; and 4) OK-DCs fused with heat-treated tumor cells. Although OK-DCs fused with unheated tumor cells efficiently enhanced CTL induction, OK-DCs fused with heat-treated tumor cells were most active, as demonstrated by: 1) up-regulation of multiple HSPs, MHC class I and II, CEA, CD80, CD86, CD83, and IL-12; 2) activation of CD4 + and CD8 + T cells able to produce IFN- γ at higher levels; 3) efficient induction of CTL activity specific for CEA or MUC1 or both against autologous tumor; and 4) superior abilities to induce CD107 + IFN-γ + CD8 + T cells and CD154 + IFN-γ + CD4 + T cells. These results strongly suggest that synergism between OK-DCs and heat-treated tumor cells enhances the immunogenicity of FCs and provides a promising means of inducing therapeutic antitumor immunity.
TL;DR: Hals-DP is safer and less invasive than Open-DP for benign or low malignant pancreatic tumors and post-operative hospital stay were significantly lower in HALS-DP than in Open- DP.
Abstract: Although the clinical benefits of hand-assisted laparoscopic surgery have been shown in several procedures including colorectal resection, splenectomy and gastrectomy, efficacy and invasiveness in pancreatic surgery have not been well investigated. We assessed the clinical benefits and invasiveness of hand-assisted laparoscopic distal pancreatectomy (HALS-DP) in relation to the occurrence of post-operative systemic inflammatory response syndrome (SIRS). Subjects comprised 8 patients underwent HALS-DP (with splenectomy, n= 7; without splenectomy, n= 1) for benign or low malignant pancreatic lesions between March 2004 and December 2005. Indications for HALS-DP consisted of mucinous cystadenoma (n= 4), endocrine tumors (n= 2), serous cystadenoma (n= 1) and pancreatic pseudocyst (n= 1). Controls comprised 9 patients who underwent conventional open distal pancreatectomy (Open-DP) for benign or low malignant lesions of the pancreas in the same period. No significant differences were identified between HALS-DP and Open-DP in operation time. However, intra-operative blood loss, CRP on post-operative day (POD) 1 [5.5 mg/dl (1.8–8.1) vs. 9.7 mg/dl (5.9–12.1); p = .006] and POD 3 [8.5 mg/dl (1.7–11.1) vs. 17.7 mg/dl (10.7–21.5); p = .003], occurrence of post-operative SIRS (13% vs. 67%; p < .05, one-sided), duration of SIRS [0 day (0–1) vs. 1 day (0–4); p = .02] and post-operative hospital stay were significantly lower in HALS-DP than in Open-DP. Furthermore, no pancreatic fistula was seen with HALS-DP, as compared to 2 (22%) with Open-DP. HALS-DP is safer and less invasive than Open-DP for benign or low malignant pancreatic tumors.
TL;DR: The peptide sequence displayed on phages A-C is consistent with chemical and biological studies of the interaction of CPTs with topoisomerase I, human E prostanoid receptor third cytoplasmic polypeptide, and a series of esterases.
TL;DR: Ketyl radical mediated tandem cyclization of omega-alkynyl carbonyl compounds bearing activated alkene using SmI(2) gave spiro[4.5]decanes stereoselectively.
TL;DR: In this article, a very rare case of malignant melanoma arising on a female nipple was reported, where a 42-year-old housewife had suffered from a small dark brown nevus on her left nipple for about thirty years without any changes.
Abstract: We report a very rare case of malignant melanoma arising on a female nipple. A 42-year-old housewife had suffered from a small dark brown nevus on her left nipple for about thirty years without any changes. Six months before her initial visit it had begun to enlarge and rapidly changed from dark brown to black. A small bleeding ulcer was also present in the center of the lesion. Malignant melanoma rather than mammary Paget’ s disease was suggested based on its clinical course. Excisional biopsy was performed to differentiate between mammary Paget’ s disease and malignant melanoma. The histopathological examination revealed malignant melanoma, about 4 mm in thickness. She then underwent wide excision with axillary lymph node dissection. The surgical margin was made in a 3 cm radius around the biopsy site. The excision included nipple, areola, and part of the underlying breast parenchyma, adipose tissue and corresponding superficial layer of fascia. Microscopy showed metastasis in one of 13 axillary lymph nodes. After the operation, the patient received adjuvant DAV-Ferron therapy. In such a case, conserving surgery based on correct diagnosis can achieve a good cosmetic result and optimal tumor control.
TL;DR: A T7 phage-based display was described to screen for paclitaxel-binding molecules from a random peptide library using paclitxel-photoimmobilized TentaGel resin and found that two phage clones included the same consensus amino acid sequence (KACGRTRVTS), which is conserved in the zinc finger domain of human NFX1.
TL;DR: A 43-year-old Japanese man with end-stage hepatitis B-related cirrhosis had undergone orthotopic liver transplantation at Baylor University Medical Center, Dallas, Texas, in 1990 and developed severe chronic hepatitis despite interferon therapy between the first and the second posttransplant year in Japan.
Abstract: To the Editor: A 43-year-old Japanese man with end-stage hepatitis B-related cirrhosis had undergone orthotopic liver transplantation at Baylor University Medical Center, Dallas, Texas, in 1990. The patient was HBV-DNA seropositive before transplantation. No hepatocellular carcinoma (HCC) was found in the explanted liver. Since therapy to prevent reinfection of hepatitis B using hepatitis B immunoglobulin (HBIG) was not available at that time, the patient was reinfected and developed severe chronic hepatitis despite interferon therapy between the first and the second posttransplant year in Japan. The liver biopsy performed 8 years after transplantation demonstrated liver cirrhosis. Fourteen years after transplantation, a single nodule of HCC, 3 cm in diameter, was diagnosed by computed tomography at the Jikei University Hospital, for which the patient underwent transcatheter arterial chemoembolization (TACE) therapy (Fig. 1) and was subsequently retransplanted at the Baylor University Medical Center 4 months after TACE. Histological examination of the HCC in the explanted liver showed poorly differentiated HCC without portal vein invasion. After retransplantation, the patient was treated with the HBIG and lamivudine (100 mg daily) to prevent reinfection with hepatitis B. In addition, the Baylor protocol of posttransplant adjuvant chemotherapy using doxorubicin (10 mg/m2 × 20 times, weekly) was given for 5 months after
TL;DR: Stereoselective synthesis of a potential intermediate bearing 11-oxabicycloundec-3-ene core, a common scaffold of biologically active germacrane-type sesquiterpenes, has been achieved.
TL;DR: In this paper, contrast-enhanced ultrasound (CEUS) with Levovist was used for the localization of ultrasonically invisible hypervascular lesions in the liver to facilitate percutaneous ultrasound-guided treatment.
TL;DR: A 41-year-old Chinese woman admitted to the authors' hospital with epigastric pain had a heterogeneous enhancement tumor fed by the left gastroepiploic artery in the left lower quadrant and cholelithiasis, which confirmed a diagnosis of hemangiopericytoma with low-grade malignancy.
TL;DR: The synthesis of the key intermediate (4) in the proposed route to D8646-2-6 is described and the stepwise dehydration reaction of the aldol adduct 14, followed by Stille coupling with vinyl stannane 5 which contained phosphonate gave the desired 4.
Abstract: The synthesis of the key intermediate (4) in the proposed route to D8646-2-6 is described. The aldol reaction of the carbohydrate-containing pyrone 7 with the aldehyde 6 was accomplished by using LiHMDS and Sc(OTf)3 or Sn(OTf)2. The stepwise dehydration reaction of the aldol adduct 14, followed by Stille coupling with vinyl stannane 5 which contained phosphonate gave the desired 4.
TL;DR: Pneumoperitoneum caused by the rupture of a gas-containing liver abscess is rare, and to the best knowledge, this is the first report, in the English-language literature, of a patient who has undergone successful hepatectomy for such a condition.
Abstract: An 84-year-old woman was admitted to our hospital with high fever, and she suddenly complained of severe abdominal pain the next day. Computed tomography revealed a gas-containing abscess in the lateral segment of the liver, with spontaneous pneumoperitoneum. An emergency lateral segmentectomy was performed, and Klebsiella pneumoniae was cultured from the liver tissue, abscess, and blood. The patient made a satisfactory recovery and was discharged on the thirty-first postoperative day. Pneumoperitoneum caused by the rupture of a gas-containing liver abscess is rare, and to our best knowledge, this is the first report, in the English-language literature, of a patient who has undergone successful hepatectomy for such a condition.
TL;DR: Total synthesis of the biologically important axane sesquiterpenes, gleenol and axenol, was accomplished through a readily available spiro[4.5]decane through Claisen rearrangement and diastereoselective reduction of ketone under the Birch conditions.
Abstract: Total synthesis of the biologically important axane sesquiterpenes, gleenol (1) and axenol (2), was accomplished through a readily available spiro[4.5]decane. The key features of the synthesis of 1 and 2 include Claisen rearrangement to afford the multi-functionalized spiro[4.5]decane 4 as a single diastereomer in excellent yield, installation of the C7 isopropyl group via ketene dithioacetal instead of direct alkylation and a diastereoselective reduction of ketone under the Birch conditions.
TL;DR: Are exon 19 deletions and L858R EGFR mutations in non-small-cell lung cancer clinically different?
Abstract: Are exon 19 deletions and L858R EGFR mutations in non-small-cell lung cancer clinically different?
TL;DR: In this paper, the first example of a Claisen rearrangement in an enantio-enriched alkenyl bicyclic dihydropyran system with perfect asymmetric transmission was presented.
Abstract: Total synthesis of (+)-α-vetispirene and (-)-agarospirol based on a Claisen rearrangement has been achieved. This is the first example of a Claisen rearrangement in an enantio-enriched alkenyl bicyclic dihydropyran system with perfect asymmetric transmission.
TL;DR: The results suggest that the inhibitory mode of action of PFOdA and PFOS is different from that mediated by the classic fatty acid inhibitors against DNA polymerase beta.
Abstract: In this study, the chemical properties of organic acids as DNA polymerase inhibitors were examined. In total, we assayed the inhibitory activities of 23 compounds. We found that the DNA synthesis activity of DNA polymerase was usually reduced to less than 50% in the presence of 100 µM monoprotic acids, which have a Clog P value greater than 7.0 and a pKa value less than 5.4. With a minor modification these chemical properties applied to several organic fatty acids previously reported as DNA polymerase inhibitors. Moreover, we also examined the inhibitory activities of perfluorooctadecanoic acid (PFOdA) and perfluorooctanesulfonic acid (PFOS) against DNA polymerase β in detail. These compounds inhibited the polymerase activity of pol β competitively with template–primer DNA, and non-competitively with dNTPs. In addition, the 8 kDa domain-defective pol β was also sensitive to these compounds. Our results suggest that the inhibitory mode of action of PFOdA and PFOS is different from that mediated by the classic fatty acid inhibitors against DNA polymerase β.
TL;DR: This is the first study of a glycolipid, SQDG, acting as a dsDNA binding inhibitor of p53, and it could be considered that a SQDD-containing thylakoid membrane in plant chloroplasts might regulate the activity of p 53 for cell division, cell cycle checkpoint and tumor suppression.
Abstract: The in vitro relationship between the human p53 DNA binding domain (p53 DBD) and glycolipids was investigated. We isolated the glycolipid fraction from spinach (Spinacia oleracea L.) and found that the fraction inhibited the double-stranded DNA (dsDNA) binding activity of p53 DBD. Since the fraction contained mainly three glycolipids, mono galactosyl diacylglycerol (MGDG), digalactosyl diacylglycerol (DGDG) and sulfoquinovosyl diacylglycerol (SQDG), and each glycolipid was purified using silica gel column chromatography. Purified SQDG inhibited the activity, however, purified MGDG and DGDG had no influence. In this study, we demonstrated the structure-function relationship between chemically synthetic SQDG and p53 DBD. The major action is probably dependent on the fatty acid effect, although SQDG was a much stronger inhibitor than the fatty acid alone present in SQDG. The inhibitory activity of SQDG was weakened by the R248A mutant of p53 DBD, suggesting that R248 in the dsDNA binding site of p53 must be important for the inhibitory activity of SQDG. SQDG binding to p53 DBD could be reversed with a non-ionic detergent, Nonidet P-40. This is the first study of a glycolipid, SQDG, acting as a dsDNA binding inhibitor of p53, and it could be considered that a SQDG-containing thylakoid membrane in plant chloroplasts might regulate the activity of p53 for cell division, cell cycle checkpoint and tumor suppression.