Tumor immune microenvironment and nivolumab efficacy in EGFR mutation-positive non-small-cell lung cancer based on T790M status after disease progression during EGFR-TKI treatment.

BACKGROUND: The efficacy of programmed death-1 blockade in epidermal growth factor receptor gene (EGFR) mutation-positive non-small-cell lung cancer (NSCLC) patients with different mechanisms of acquired resistance to EGFR tyrosine kinase inhibitors (TKIs) is unknown. We retrospectively evaluated nivolumab efficacy and immune-related factors in such patients according to their status for the T790M resistance mutation of EGFR. PATIENTS AND METHODS: We identified 25 patients with EGFR mutation-positive NSCLC who were treated with nivolumab after disease progression during EGFR-TKI treatment (cohort A). Programmed death-ligand 1 (PD-L1) expression and tumor-infiltrating lymphocyte (TIL) density in tumor specimens obtained after acquisition of EGFR-TKI resistance were determined by immunohistochemistry. Whole-exome sequencing of tumor DNA was carried out to identify gene alterations. The relation of T790M status to PD-L1 expression or TIL density was also examined in an independent cohort of 60 patients (cohort B). RESULTS: In cohort A, median progression-free survival (PFS) was 2.1 and 1.3 months for T790M-negative and T790M-positive patients, respectively (P = 0.099; hazard ratio of 0.48 with a 95% confidence interval of 0.20-1.24). Median PFS was 2.1 and 1.3 months for patients with a PD-L1 expression level of ≥1% or <1%, respectively (P = 0.084; hazard ratio of 0.37, 95% confidence interval of 0.10-1.21). PFS tended to increase as the PD-L1 expression level increased with cutoff values of ≥10% and ≥50%. The proportion of tumors with a PD-L1 level of ≥10% or ≥50% was higher among T790M-negative patients than among T790M-positive patients of both cohorts A and B. Nivolumab responders had a significantly higher CD8+ TIL density and nonsynonymous mutation burden. CONCLUSION: T790M-negative patients with EGFR mutation-positive NSCLC are more likely to benefit from nivolumab after EGFR-TKI treatment, possibly as a result of a higher PD-L1 expression level, than are T790M-positive patients.

Prospective and clinical validation of ALK immunohistochemistry: results from the phase I/II study of alectinib for ALK-positive lung cancer (AF-001JP study).

BACKGROUND: Anaplastic lymphoma kinase (ALK) fusions need to be accurately and efficiently detected for ALK inhibitor therapy. Fluorescence in situ hybridization (FISH) remains the reference test. Although increasing data are supporting that ALK immunohistochemistry (IHC) is highly concordant with FISH, IHC screening needed to be clinically and prospectively validated. PATIENTS AND METHODS: In the AF-001JP trial for alectinib, 436 patients were screened for ALK fusions through IHC (n = 384) confirmed with FISH (n = 181), multiplex RT-PCR (n = 68), or both (n = 16). IHC results were scored with iScore. RESULT: ALK fusion was positive in 137 patients and negative in 250 patients. Since the presence of cancer cells in the samples for RT-PCR was not confirmed, ALK fusion negativity could not be ascertained in 49 patients. IHC interpreted with iScore showed a 99.4% (173/174) concordance with FISH. All 41 patients who had iScore 3 and were enrolled in phase II showed at least 30% tumor reduction with 92.7% overall response rate. Two IHC-positive patients with an atypical FISH pattern responded to ALK inhibitor therapy. The reduction rate was not correlated with IHC staining intensity. CONCLUSIONS: Our study showed (i) that when sufficiently sensitive and appropriately interpreted, IHC can be a stand-alone diagnostic for ALK inhibitor therapies; (ii) that when atypical FISH patterns are accompanied by IHC positivity, the patients should be considered as candidates for ALK inhibitor therapies, and (iii) that the expression level of ALK fusion is not related to the level of response to ALK inhibitors and is thus not required for patient selection. REGISTRATION NUMBER: JapicCTI-101264 (This study is registered with the Japan Pharmaceutical Information Center).

Metformin prevents liver tumorigenesis induced by high-fat diet in C57Bl/6 mice.

The prevalence of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) is increasing with the growing epidemics of obesity and diabetes. NAFLD encompasses a clinicopathologic spectrum of disease ranging from isolated hepatic steatosis to NASH, which is a more aggressive form of fatty liver disease, to cirrhosis and, finally, hepatocellular carcinoma (HCC). The exact mechanism behind the development of HCC in NASH remains unclear; however, it has been established that hepatic steatosis is the important risk factor in the development of HCC. Metformin has recently drawn attention because of its potential antitumor effect. Here, we investigated the effects of metformin on high-fat diet (HFD)-induced liver tumorigenesis, using a mouse model of NASH and liver tumor. Metformin prevented long-term HFD-induced liver tumorigenesis in C57Bl/6 mice. Of note, metformin failed to protect against liver tumorigenesis in mice that had already begun to develop NAFLD. Metformin improved short-term HFD-induced fat accumulation in the liver, associated with the suppression of adipose tissue inflammation. Collectively, these results suggest that metformin may prevent liver tumorigenesis via suppression of liver fat accumulation in the early stage, before the onset of NAFLD, which seems to be associated with a delay in the development of inflammation of the adipose tissue.

Clinical characteristics classified by the serum KL-6 level in patients with organizing pneumonia.

BACKGROUND: The serum Krebs von der Lungen-6 (KL-6) level is a useful marker correlated with the severity of various interstitial lung diseases. There have been few reports about the clinical characteristics of organizing pneumonia (OP) associated with the serum KL-6 levels. OBJECTIVE: This study was performed to determine whether the serum KL-6 levels can help determine the optimal treatment for OP. DESIGNS: Patients diagnosed with OP by clinical, radiological and histopathological findings were retrospectively reviewed. The OP patients were classified into two groups based on their serum KL-6 levels: normal KL-6 and high KL-6 groups. The two groups were compared with regard to their clinical and radiological data and therapeutic response one month after the start of treatment. RESULTS: The clinical records of twenty-two patients diagnosed with OP were reviewed. The serum KL-6 level was elevated in 11 of the 22 patients. There were no obvious differences in the clinical data between the two groups, although patients in the normal KL-6 group tended to have a fever. There were no significant differences in the chest X-ray (CXR) score or computed tomography (CT) score between the two groups. The CXR scores were correlated with the serum KL-6 levels. At 1 month after the diagnosis, 11 patients who needed treatment with prednisolone were included in the high KL-6 group. CONCLUSIONS: Patients with normal KL-6 levels showed lower CXR and CT scores. The serum KL-6 level on admission is a useful marker to judge the need for corticosteroid treatment in OP patients.

Control of beta cell function and proliferation in mice stimulated by small-molecule glucokinase activator under various conditions.

AIMS/HYPOTHESIS: We investigated changes in the expression of genes involved in beta cell function and proliferation in mouse islets stimulated with glucokinase activator (GKA) in order to elucidate the mechanisms by which GKA stimulates beta cell function and proliferation. METHODS: Islets isolated from mice were used to investigate changes in the expression of genes related to beta cell function and proliferation stimulated by GKA. In addition, Irs2 knockout (Irs2 (-/-)) mice on a high-fat diet or a high-fat diet containing GKA were used to investigate the effects of GKA on beta cell proliferation in vivo. RESULTS: In wild-type mice, Irs2 and Pdx1 expression was increased by GKA. In Irs2 (-/-) mice, GKA administration increased the glucose-stimulated secretion of insulin and Pdx1 expression, but not beta cell proliferation. It was particularly noteworthy that oxidative stress inhibited the upregulation of the Irs2 and Pdx1 genes induced by GKA. Moreover, whereas neither GKA alone nor exendin-4 alone upregulated the expression of Irs2 and Pdx1 in the islets of db/db mice, prior administration of exendin-4 to the mice caused GKA to increase the expression of these genes. CONCLUSIONS/INTERPRETATION: GKA-stimulated IRS2 production affected beta cell proliferation but not beta cell function. Oxidative stress diminished the effects of GKA on the changes in expression of genes involved in beta cell function and proliferation. A combination of GKA and an incretin-related agent might therefore be effective in therapy.

Identification of novel helper epitopes of MAGE-A4 tumour antigen: useful tool for the propagation of Th1 cells.

MAGE-A4 has been considered as an attractive cancer-testis (CT) antigen for tumour immunotherapy. It has been well accepted that T-helper type 1 (Th1) cell-dominant immunity is critical for the successful induction of antitumour immunity in a tumour-bearing host. The adoptive Th1 cell therapy has been shown to be an attractive strategy for inducing tumour eradication in mouse systems. However, Th1-cell therapy using human tumour-specific Th1 cells, which were expanded from peripheral blood mononuclear cells (PBMCs) in a clinically useful protocol, has never been performed. Here, we first identified MAGE-A4-derived promiscuous helper epitope, peptide (MAGE-A4 280-299), bound to both HLA-DPB1(*)0501 and DRB1(*)1403. Using the peptide, we established a suitable protocol for the propagation of MAGE-A4-specific Th1 cells in vitro. Culture of CD4(+) T cells with IFN-gamma-treated PBMC-derived adherent cells in the presence of helper epitope peptide resulted in a great expansion of MAGE-A4-reactive Th cells producing IFN-gamma , but not IL-4. Moreover, it was shown that ligation of MAGE-A4-reactive Th1 cells with the cognate peptide caused the production of IFN-gamma and IL-2. Thus, our identified MAGE-A4 helper epitope peptide will become a good tool for the propagation of tumour-specific Th1 cells applicable to adoptive immunotherapy of human cancer.

Transgenic rescue from embryonic lethality and renal carcinogenesis in the Nihon rat model by introduction of a wild-type Bhd gene.

We recently reported that a germline insertion of a single nucleotide in the rat homologue of the human Birt-Hogg-Dubé gene (BHD) gives rise to dominantly inherited cancer in the Nihon rat model. In this study, we constructed transgenic Nihon rats with introduction of a wild-type Bhd gene to ascertain whether suppression of the Nihon phenotype is possible. Rescue from embryonic lethality of mutant homozygotes (Nihon/Nihon) and suppression of renal carcinogenesis in heterozygotes (Nihon/+) were both observed, defining the germline Bhd mutation in the Nihon rat as an embryonal lethal and tumor predisposing mutation. This transgenic rescue system will be useful to analyse Bhd gene function, its relation to tumorigenesis in vivo, and genetic-environmental interactions in carcinogenesis.

Spontaneous hepatic copper accumulation in Long-Evans Cinnamon rats with hereditary hepatitis. A model of Wilson's disease.

Long-Evans Cinnamon (LEC) rats, an inbred strain of a mutant rat isolated from Long-Evans rats, develop hereditary hepatitis. To elucidate the role of copper metabolism in the development of the hepatitis in LEC rats, we examined the copper concentration in the tissues and serum levels of copper and ceruloplasmin. Copper concentration in the liver of LEC rats was over 40 times that of normal Long-Evans Agouti (LEA) rats, while the serum ceruloplasmin and copper concentrations in LEC rats decreased significantly. The hepatocytes of LEC rats show steatosis in cytoplasm and pleomorphism of mitochondria, resembling the histologic features of the liver in Wilson's disease. These findings suggest that the hereditary hepatitis in LEC rats is closely associated with copper toxicity, and may be dealing with a rat form of Wilson's disease. Thus the LEC rats will provide a unique and useful animal model for clarifying the mechanism and for developing treatment strategies for Wilson's disease and other abnormal copper metabolism in humans.

Increased production of cytotoxic macrophage progenitors by Lactobacillus casei in mice.

Heat-killed Lactobacillus casei YIT9018 (LC9018), when administered intravenously to normal mice, induced increase in Mac-1+ cells and Mac-2+ cells but not in Mac-3+ cells in spleen. The number of both populations changed in the same time course and was maximal 14 d after the administration. To know the effect of LC9018 on hematopoietic progenitor level, we examined the number of macrophage colony-forming cells (M-CFC), granulocyte-macrophage CFC (GM-CFC), and colony-forming units in spleen (CFU-S) in bone marrow 3 d after the administration. LC9018 stimulated the proliferation of M-CFC but not that of GM-CFC and CFU-S. LC9018-induced M-CFC were similar to normal M-CFC in dependence on macrophage colony-stimulating factor (M-CSF) and buoyant density. M-CFC-derived macrophages cultured in the presence of M-CSF expressed Mac-1 and Mac-2 but not Mac-3. They showed cytotoxic activity against syngenic tumor cells, Meth A, via direct contact, when assayed by using an in vitro colony inhibition assay or an in vivo Winn test. These results indicate that LC9018 stimulates the proliferation of cytotoxic macrophage progenitors in bone marrow and induces their differentiation in spleen. These effects may be one of the ways in which LC9018 suppresses tumor growth.

The OCT4 pseudogene POU5F1B is amplified and promotes an aggressive phenotype in gastric cancer.

POU5F1B (POU domain class 5 transcription factor 1B), a processed pseudogene that is highly homologous to OCT4, was recently shown to be transcribed in cancer cells, but its clinical relevance and biological function have remained unclear. We now show that POU5F1B, which is located adjacent to MYC on human chromosome 8q24, is frequently amplified in gastric cancer (GC) cell lines. POU5F1B, but not OCT4, was also found to be expressed at a high level in GC cell lines and clinical specimens. In addition, the DNA copy number and mRNA abundance for POU5F1B showed a positive correlation in both cancer cell lines and GC specimens. Overexpression of POU5F1B in GC cells promoted colony formation in vitro as well as both tumorigenicity and tumor growth in vivo, and these effects were enhanced in the additional presence of MYC overexpression. Furthermore, knockdown of POU5F1B expression with a short hairpin RNA confirmed a role for the endogenous pseudogene in the promotion of cancer cell growth in vitro and tumor growth in vivo. POU5F1B overexpression induced upregulation of various growth factors in GC cells as well as exhibited mitogenic, angiogenic and antiapoptotic effects in GC xenografts. Finally, amplification of POU5F1B was detected in 17 (12%) of 145 cases of GC and was a significant predictor of poor prognosis in patients with stage IV disease. In conclusion, we found that the POU5F1B pseudogene is amplified and expressed at a high level in, as well as confers an aggressive phenotype on, GC, and that POU5F1B amplification is associated with a poor prognosis in GC patients.

Increased expression of c-jun gene during spontaneous hepatocarcinogenesis in LEC rats.

We have studied the expressions of nine proto-oncogenes (c-myc, N-myc, c-fos, C-jun, p53, H-ras, N-ras, c-raf, hst) and two other genes (PCNA, GST-P) during the spontaneous development of hepatocellular carcinomas (HCCs) in LEC rats. Expression of c-myc, H-ras, N-ras, C-raf, p53 and PCNA genes was detected, but this did not significantly change during the development of HCCs in LEC rats. Expression of N-myc and hst genes was not detectable. Expression of c-fos gene was detected in one HCC case out of four. Significantly increased expression of c-jun gene was observed in the liver tissues of LEC rats aged 8 months. This high expression was decreased with the development of HCCs. On the other hand, the expression of GST-P gene increased in parallel with the clinical course of the development of HCCs in LEC rats. The pattern of c-jun mRNA augmentation was different from that of GST-P mRNA. These observations suggest that c-jun gene may play a role in the spontaneous development of HCCs in LEC rats.

Analysis of the expression of intercellular adhesion molecule-1 in cells of the human bronchial epithelial cell line NCI-H292.

The mechanism of the expression of intercellular adhesion molecule-1 (ICAM-1) on epithelial cells was analyzed using NCI-H292 cells, a human bronchial epithelial cell line. Treatment with interferon-gamma (100 U/ml) or the protein kinase C activator 12-O-tetradecanoylphorbol 13-acetate (TPA) (16.2 nM) induced ICAM-1 expression. The interferon-gamma-induced ICAM-1 expression was reduced by the tyrosine kinase inhibitor genistein (4',5,7-trihydroxyisoflavone) (37 to 185 microM), but not by the protein kinase C inhibitor Ro 31-8425 ((3-[8-(aminomethyl)-6,7,8,9-tetrahydropyrido [1.2-a]indol-10-yl]-4-(1-methyl-1 H-pyrrole-2,3-dione) (10 microM). The TPA-induced ICAM-1 expression was reduced by the protein kinase C inhibitor Ro 31-8425 (1 to 10 microM), but not by the tyrosine kinase inhibitor genistein (185 microM). The protein kinase A inhibitor H-89 (N-[2-((p-bromocinnamyl)amino)ethyl]-5-isoquinolinesulfonamide) did not affect the ICAM-1 expression induced by interferon-gamma or TPA. Pyrrolidine dithiocarbamate (1-pyrrolidinecarbodithioic acid) (100 microM), an inhibitor of nuclear factor kappaB (NF-kappaB) activation. enhanced the ICAM-1 expression induced by interferon-y, but reduced that induced by TPA. The changes in ICAM-1 expression on the cell surface were correlated with the changes in ICAM-1 mRNA levels. Combined treatment with interferon-gamma and TPA induced more than additive ICAM-1 expression. These findings suggest that interferon-gamma induces ICAM-1 expression by a tyrosine kinase-dependent mechanism, but that TPA induces it by a protein kinase C- and NF-kappaB-dependent mechanism.

Analysis of a uranium solution for evaluating the total number of fissions in the JCO criticality accident in Tokai-mura.

The uranium solution in the precipitation tank in the JCO's uranium conversion facility was analyzed in order to evaluate the total number of fissions in the criticality accident. Two analytical groups at JAERI performed chemical analyses independently in order to check the validity of the results: the concentration of the fission products (95Zr, 99Mo, 103Ru, 131I, 140Ba, etc), uranium, boron and impurity elements in the solution. The analytical results obtained by the two groups were almost in agreement within the analytical error. The number of fissions per one gram of uranium in the accident was determined to be (1.5 +/- 0.1 ) x 10(14). Also, the total number of events was evaluated to be (2.5 +/- 0.1) x 10(18) fissions using the total amount of uranium (16.6 kg) fed into the precipitation tank at the accident.

Transitions induced by the discreteness of molecules in a small autocatalytic system.

The autocatalytic reaction system with a small number of molecules is studied numerically by stochastic particle simulations. A novel state due to fluctuation and discreteness in molecular numbers is found, characterized as an extinction of molecule species alternately in the autocatalytic reaction loop. Phase transition to this state with changes of the system size and flow is studied, while a single-molecule switch of the molecule distributions is reported. The relevance of the results to intracellular processes is briefly discussed.

Rat macrophage activation after treatment with the bleomycin group of antitumour antibiotics in vivo.

We have previously reported that bleomycin and its derivative peplomycin enhance the release of cytokines by rat spleen cells during mitogen-stimulated cell culture in vitro, but liblomycin, another derivative of bleomycin, decreases cytokine release to below untreated control levels. Cytokine release correlated well with the inhibition of subcutaneous tumour growth after treatment with equivalent doses of the three analogues. In contrast, ascites tumour growth is completely inhibited by liblomycin and appears to be at least partly macrophage-mediated because the antitumour effect can be significantly inhibited by carageenan. This study shows that bleomycin and its analogues activate rat peritoneal macrophages and increase interleukin-6 release, O2- production, cell spreading, phagocytosis and random migration of macrophages, but only bleomycin enhances peritoneal macrophage invasion into a monolayer of rat lung endothelial cells in vitro. This study also shows that although liblomycin decreases spleen cell cytokine production and is less effective than bleomycin against subcutaneous tumour, as we have previously reported, the antitumour drug activates peritoneal macrophages and, compared to bleomycin, has a remarkable therapeutic effect on rat ascites tumour.

Relevance of irinotecan hydrochloride-induced diarrhea to the level of prostaglandin E2 and water absorption of large intestine in rats.

For characterization of the mechanism(s) of severe diarrhea due to the anticancer agent, irinotecan hydrochloride (CPT-11), examination was made of the relation of CPT-11-related diarrhea to colonic prostaglandin E2 (PGE2) and water absorption in rats. Acute diarrheal symptoms were observed within 1 hr after the administration of CPT-11 to rats, with increased PGE2 and decreased water absorption in the colon. Treatment with atropine at 1 mg/kg, s.c. was noted to inhibit intestinal PGE2 and the CPT-11-related acute diarrheal symptoms, indicating that these diarrheal symptoms were mediated through the cholinergic nervous system accelerated functionally by CPT-11. On the other hand, daily treatment of CPT-11 at the same dose resulted in chronic diarrheal symptoms in all animals 3 days after CPT-11 treatment. Histopathological changes observed in the descending colon and ileum of the rats included degeneration and necrosis of villi and cryptal cells and a decrease in the number of the goblet cells. Significantly increased PGE2 and impaired water absorption of the descending colon were also observed during the chronic diarrheal stage. It can be considered that the chronic diarrheal symptoms appear as a consequence of the gastrointestinal injury characterized by significant increase in PGE2 accompanied by impaired water absorption.

T cell receptor-independent cell-mediated cytotoxicity by nude mouse lymphokine-activated killer cells.

Lymphokine-activated killer (LAK) cells, which can lyse a variety of tumor cells, can be induced from both normal and athymic nude mouse spleen cells by culture with high doses of recombinant interleukin 2 (rIL-2). LAK cells generated from nude mouse spleen cells (Nude-LAK cells) express just Thy 1.2 antigen, but not CD4 and CD8 antigens. Nude-LAK cells express neither T3 molecule, T cell receptor (TCR) alpha beta nor TCR gamma delta on their cell surface. The lack of TCR expression on Nude-LAK cells was confirmed by the results of northern blot analysis. LAK cells generated from normal mouse spleen cells (Nor-LAK) express TCR alpha, beta transcripts, while Nude-LAK cells express only sterile TCR beta transcript, but not TCR alpha transcript. TCR gamma delta transcripts were scarcely detected in both Nor-LAK cells and Nude-LAK cells. Thus, it is strongly suggested that Nude-LAK cells can recognize and lyse tumor cells by TCR-independent mechanisms. Monoclonal antibody against lymphocyte function-associated antigen (LFA-1) molecule can block the cytotoxicity of Nude-LAK cells, indicating an important role of such accessory molecules in Nude-LAK cell-mediated cytotoxicity.

Augmented accumulation of transferred lymphokine-activated killer (LAK) cells at murine tumor sites through production of LAK-attractant facilitated by chemotherapy.

We observed that effects of adoptive immunotherapy with lymphokine-activated killer (LAK) cells on BMT-11, a fibrosarcoma in C57BL/6 mice were improved by combination with cyclophosphamide (CY)-chemotherapy corresponding to enhanced accumulation at tumor sites of LAK cells. On the other hand, cytotoxic T lymphocytes (CTLs) which were able to accumulate at tumor sites more densely than LAK cells produced significant therapeutic effects by themselves. We have also found observed that LAK-attractant activity was detected in conditioned medium (CM) of CY-treated tumor tissue but not in the CM of untreated tumor tissue. These findings reveal that CY-chemotherapy facilitates LAK-attractant-production and enhances the accumulation in tumor tissue of LAK cells and that therapeutic effects of adoptive transfer of LAK cells are augmented by cancer chemotherapy through the enhanced accumulation of LAK cells.