Validation of the digital PCR system in tyrosine kinase inhibitor-resistant EGFR mutant non-small-cell lung cancer.

The aim of this study was to compare the accuracy of the QuantStudio 3D Digital polymerase chain reaction (dPCR) system and a PCR-based next generation sequencing (NGS) system for detecting a secondary mutation in the epidermal growth factor receptor (EGFR) gene T790M in non-small cell lung cancer (NSCLC) patients previously diagnosed with EGFR-activating mutations. Twenty-five patients with NSCLC previously treated with EGFR-TKIs were examined. The patients were treated daily with either erlotinib or gefitinib. New biopsies, followed by DNA sequencing on an Ion Torrent systems using the Ion Torrent AmpliSeq Cancer Hotspot Panel and dPCR were performed. A comparison of NGS, sensitive PCR, and dPCR revealed that the sensitivities of NGS and dPCR were similar in this study. As well, T790M was detected in as low as about 5% of mutant allelic frequencies, which represented 5% of the total reads on site mapped reads in NGS and greater than 5% of the dPCR reads, which represented mutant and wild type copies. The strategy in which NGS sequencing is followed by revealed acquired mutation with dPCR may be a reasonable one. We demonstrated the utility of combining NGS and dPCR as a tool for monitoring T790M. NGS and dPCR with formalin-fixed paraffin-embedded (FFPE) specimens might become a standard genomic test for exploring acquired resistance to targeted molecular medicines.

Programmed death-ligand 1 expression and T790M status in EGFR-mutant non-small cell lung cancer.

BACKGROUND: Differential biology and prognosis between T790M+ and T790M- populations imply immunological differences also. METHODS: We retrospectively analyzed programmed death-ligand 1 (PD-L1) expression and T790M status in rebiopsied samples of epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC). PD-L1 immunohistochemistry was performed using the SP142 antibody for tumour cell (TC) and tumour-infiltrating immune cell (IC) and the 28-8 antibody for TC. PD-L1+ was defined as TC or IC ≥1%. RESULTS: We investigated 67 available rebiopsied histologic samples in 47 patients. Using the SP142, prevalence of PD-L1 any+, moderate+, and strong+ in T790M+ vs. T790M- samples were 31% vs. 61%, 8% vs. 15%, and 0% vs. 2%, respectively, representing PD-L1+ prevalence of T790M+ samples was significantly lower than that of T790M- (p=0.0149). Prevalence of any TC+/IC+ in T790M+ vs. T790M- samples were TC: 31% vs. 51% (p=0.0997) and IC: 8% vs. 27% (p=0.0536), respectively. Using the 28-8, median percentage of PD-L1+ in T790M+ samples was 1.9 (range, 0-27.2), whereas T790M- was 4.1 (range, 0-89.8) (p=0.0801). Prevalence of PD-L1+ ≥1%, ≥5%, and ≥10% in T790M+ vs. T790M- samples were 77% vs. 83% (p=0.5476), 31% vs. 49% (p=0.1419), and 12% vs. 27% (p=0.1213), respectively. In 9 of 11 patients receiving multiple rebiopsies, T790M and/or PD-L1 expression revealed temporal dynamism. Survival curves according to PD-L1 expression/T790M status suggested better prognosis in PD-L1-/T790M+ population. CONCLUSIONS: T790M+ status was correlated to lower PD-L1 expression. PD-L1 expression might have a prognostic value and interaction with T790M mutation in EGFR-mutant NSCLC.

PD-L1 Expression in Patients with Non-small Cell Lung Cancer.

AIM: The aim of this study was to evaluate whether irradiation induces the expression of tumor programed cell death ligand 1 (PD-L1) in patients with non-small cell lung cancer (NSCLC). PATIENTS AND METHODS: Seventeen patients with NSCLC who received chemoradiotherapy and underwent tumor resection and six patients whose pre-treatment biopsy specimens were available, were analyzed by immunohistochemistry for PD-L1 expression between September 2011 and June 2016 at the Institute of Biomedical Research and Innovation Hospital. RESULTS: Among six patients for which pre-irradiation biopsy samples were available, the H-score for PD-L1 was reduced after irradiation following staining with two different antibody clones (SP28-8 and SP142). A PD-L1 H-score >5 with SP28-8 antibody (hazard ratio=6.46; 95% confidence interval=1.209-34.53; p=0.029) was a significant negative factor for duration of progression-free survival after curative operation or chemoradiation. CONCLUSION: We showed that tumor PD-L1 expression decreased in patients with NSCLC who received chemoradiotherapy and radiation resistance might be due to pre-treatment PD-L1 expression.

Programmed death-ligand 1 expression according to epidermal growth factor receptor mutation status in pretreated non-small cell lung cancer.

BACKGROUND: Current clinical trials have suggested poorer efficacies of anti-programmed death-1 (PD-1)/PD-ligand 1 (PD-L1) immunotherapies for non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations, implying lower PD-L1 expression in EGFR-mutant NSCLC than in EGFR-wild type. METHODS: We retrospectively analyzed correlation between PD-L1 expression and EGFR status in clinical samples of pretreated NSCLC. PD-L1 immunohistochemistry was performed using the 28-8 anti-PD-L1 antibody for tumor cell membrane staining. H-score was adopted to evaluate both percentage and intensity. We investigated H-scores ≥1, ≥5, and ≥10 as PD-L1+ cut-offs. H-score ≥10 was defined as strong PD-L1+. RESULTS: We investigated 96 available histologic samples in 77 pretreated patients with NSCLC. Median H-score in EGFR-mutant samples (n=65) was 3 (range, 0-150), whereas EGFR-wild-type (n=31) was 8 (range, 0-134) (p=0.0075). Using H-scores ≥1, ≥5, and ≥10 cut-offs, incidence of PD-L1+ in EGFR-mutant vs. EGFR-wild-type samples were: 85% (55/65) vs. 94% (29/31) (p=0.2159); 42% (27/65) vs. 74% (23/31) (p=0.0027); and 22% (14/65) vs. 48% (15/31) (p=0.0074), respectively. Patient-oriented (n=77) univariate analysis for strong PD-L1+ found age of sample (p=0.0226) and EGFR mutation status (p=0.0490) as significant factors. Multivariate analysis identified EGFR mutation status as the only significant factor (p=0.0121, odds ratio 2.99) for strong PD-L1+. H-scores of PD-L1 expression varied in all 11 cases receiving multiple rebiopsies, and categories of positivity migrated in 10 (91%) of 11 patients. CONCLUSIONS: PD-L1 expression was significantly lower in EGFR-mutant NSCLC samples than in EGFR wild-type samples. Its expression could be dynamic and affected by age of sample.

Next-generation sequencing of tyrosine kinase inhibitor-resistant non-small-cell lung cancers in patients harboring epidermal growth factor-activating mutations.

BACKGROUND: The aim of this study was to detect the epidermal growth factor receptor (EGFR)-activating mutations and other oncogene alterations in patients with non-small-cell lung cancers (NSCLC) who experienced a treatment failure in response to EGFR-tyrosine kinase inhibitors (TKIs) with a next generation sequencer. METHODS: Fifteen patients with advanced NSCLC previously treated with EGFR-TKIs were examined between August 2005 and October 2014. For each case, new biopsies were performed, followed by DNA sequencing on an Ion Torrent Personal Genome Machine (PGM) system using the Ion AmpliSeq Cancer Hotspot Panel version 2. RESULTS: All 15 patients were diagnosed with NSCLC harboring EGFR-activating mutations (seven cases of exon 19 deletion, seven cases of L858R in exon 21, and one case of L861Q in exon 21). Of the 15 cases, acquired T790M resistance mutations were detected in 9 (60.0%) patients. In addition, other mutations were identified outside of EGFR, including 13 cases (86.7%) exhibiting TP53 P72R mutations, 5 cases (33.3%) of KDR Q472H, and 2 cases (13.3%) of KIT M541L. CONCLUSIONS: Here, we showed that next-generation sequencing (NGS) is able to detect EGFR T790M mutations in cases not readily diagnosed by other conventional methods. Significant differences in the degree of EGFR T790M and other EGFR-activating mutations may be indicative of the heterogeneity of disease phenotype evident within these patients. The co-existence of known oncogenic mutations within each of these patients may play a role in acquired EGFR-TKIs resistance, suggesting the need for alternative treatment strategies, with PCR-based NGS playing an important role in disease diagnosis.

Validation of an Ion Torrent Sequencing Platform for the Detection of Gene Mutations in Biopsy Specimens from Patients with Non-Small-Cell Lung Cancer.

BACKGROUND: Treatment for patients with advanced non-small cell lung cancer (NSCLC) is often determined by the presence of biomarkers that predict the response to agents targeting specific molecular pathways. Demands for multiplex analysis of the genes involved in the pathogenesis of NSCLC are increasing. METHODS: We validated the Ion Torrent Personal Genome Machine (PGM) system using the Ion AmpliSeq Cancer Hotspot Panel and compared the results with those obtained using the gold standard methods, conventional PCR and Sanger sequencing. The cycleave PCR method was used to verify the results. RESULTS AND CONCLUSION: The Ion Torrent PGM resulted in a similar level of accuracy in identifying multiple genetic mutations in parallel, compared with conventional PCR and Sanger sequencing; however, the Ion Torrent PGM was superior to the other sequencing methods in terms of increased ease of use, even when taking into account the small amount of DNA that was obtained from formalin-fixed paraffin embedded (FFPE) biopsy specimens.

Regulation of growth hormone secretion by (pro)renin receptor.

(Pro)renin receptor (PRR) has a single transmembrane domain that co-purifies with the vacuolar H(+)-ATPase (V-ATPase). In addition to its role in cellular acidification, V-ATPase has been implicated in membrane fusion and exocytosis via its Vo domain. Results from the present study show that PRR is expressed in pituitary adenoma cells and regulates growth hormone (GH) release via V-ATPase-induced cellular acidification. Positive PRR immunoreactivity was detected more often in surgically resected, growth hormone-producing adenomas (GHomas) than in nonfunctional pituitary adenomas. GHomas strongly expressing PRR showed excess GH secretion, as evidenced by distinctly high plasma GH and insulin-like growth factor-1 levels, as well as an elevated nadir GH in response to the oral glucose tolerance test. Suppression of PRR expression in rat GHoma-derived GH3 cells using PRR siRNA resulted in reduced GH secretion and significantly enhanced intracellular GH accumulation. GH3 treatment with bafilomycin A1, a V-ATPase inhibitor, also blocked GH release, indicating mediation via impaired cellular acidification of V-ATPase. PRR knockdown decreased Atp6l, a subunit of the Vo domain that destabilizes V-ATPase assembly, increased intracellular GH, and decreased GH release. To our knowledge, this is the first report demonstrating a pivotal role for PRR in a pituitary hormone release mechanism.

Ectopic ACTH syndrome caused by desmopressin-responsive thymic neuroendocrine tumor.

A 32-year-old Chinese woman with rapid weight gain and progressive edema was found to have typical Cushingoid features. Her endocrine data were consistent with a diagnosis of ACTH-dependent Cushing's syndrome. To differentiate ectopic ACTH syndrome (EAS) from Cushing's disease (CD), various dynamic endocrine and imaging tests were performed. Her ACTH response was negative to corticotropin-releasing hormone (CRH) and positive to desmopressin. Magnetic resonance imaging of the pituitary showed no mass lesion. Computed tomography scan of the chest revealed a large mass (21 × 15 mm) in the anterior mediastinum, where positron emission tomography showed accumulation of [(18)F] fluorodeoxyglucose. Selective venous sampling showed marked step-up in ACTH level in the internal thoracic vein but not in the cavernous sinus after CRH stimulation. These data are compatible with the diagnosis of EAS. The resected tumor was pathologically consistent with thymic neuroendocrine tumor (NET) positive for ACTH by immunohistochemistry and abundant V1b receptor gene expression by RT-PCR. Postoperatively, her circulating ACTH/cortisol levels became normalized, and responded to stimulation with CRH but not with desmopressin. Her Cushingoid appearance gradually disappeared, and she was free from recurrence 5 years after surgery. This is a rare case of desmopressin-responsive EAS caused by thymic NET with predominant V1b gene expression, which was successfully localized by imaging modalities combined with selective venous sampling.

A Case of Rathke's Cleft Cyst Associated with Transient Central Adrenal Insufficiency and Masked Diabetes Insipidus.

A 73-year-old woman admitted to our hospital because of headache, poor appetite, malaise, weight loss, and vomiting was found to have central adrenal insufficiency and thyrotoxicosis due to silent thyroiditis. Polyuria developed after replacement with glucocorticoid (masked diabetes insipidus), which was controlled with nasal administration of desmopressin. Magnetic resonance imaging of the brain showed a large cystic pituitary mass (18 × 18 × 12 mm) extending suprasellarly to the optic chiasm. Transsphenoidal surgery revealed that the pituitary tumor was Rathke's cleft cyst. Following surgery, replacement with neither glucocorticoid nor desmopressin was needed any more. Therefore, it is suggested that Rathke's cleft cyst is responsible for the masked diabetes insipidus and the central insufficiency. Furthermore, it is speculated that thyrotoxicosis with painless thyroiditis might induce changes from subclinical adrenal insufficiency to transiently overt insufficiency.

Multimolecular salivary mucin complex is altered in saliva of cigarette smokers: detection of disulfide bridges by Raman spectroscopy.

Saliva contains mucins, which protect epithelial cells. We showed a smaller amount of salivary mucin, both MG1 and MG2, in the premenopausal female smokers than in their nonsmoking counterparts. Smokers' MG1, which contains almost 2% cysteine/half cystine in its amino acid residues, turned out to be chemically altered in the nonsmoker's saliva. The smaller acidic glycoprotein bands were detectable only in smoker's saliva in the range of 20-25 kDa and at 45 kDa, suggesting that degradation, at least in part, caused the reduction of MG1 mucin. This is in agreement with the previous finding that free radicals in cigarette smoke modify mucins in both sugar and protein moieties. Moreover, proteins such as amylase and albumin are bound to other proteins through disulfide bonds and are identifiable only after reduction with DTT. Confocal laser Raman microspectroscopy identified a disulfide stretch band of significantly stronger intensity per protein in the stimulated saliva of smokers alone. We conclude that the saliva of smokers, especially stimulated saliva, contains significantly more oxidized form of proteins with increased disulfide bridges, that reduces protection for oral epithelium. Raman microspectroscopy can be used for an easy detection of the damaged salivary proteins.

Evaluation of salivary cortisol measurements for the diagnosis of subclinical Cushing's syndrome.

Late-night salivary cortisol (NSC) has been recognized as a sensitive and easy-to-perform screening test for the diagnosis of overt Cushing's syndrome (CS). However, there have been few reports on the diagnostic utility of salivary cortisol (SC) measurement in the diagnosis of subclinical Cushing's syndrome (SCS). Therefore, the present study was designed to evaluate the usefulness of SC measurements at late-night and after overnight 1 mg dexamethasone suppression test (DST) for the diagnosis of SCS in 42 patients with adrenal incidentaloma. We evaluated 16 patients with SCS, 12 with nonfunctioning adenoma (NFA), 8 with primary aldosteronism (PA), and 6 with pheochromocytoma (Pheo). NSC levels in SCS patients (0.238 ± 0.106 µg/dL) were significantly (P < 0.05) higher than those in NFA patients (0.154 ± 0.104 µg/dL); the cutoff value (0.11 µg/dL) by ROC analysis gave high sensitivity (100%) with low specificity (50%). Post DST SC levels in SCS patients (0.238 ± 0.116 µg/dL) were significantly (P = 0.0081) higher than those in NFA patients (0.136 ± 0.110 µg/dL); the cutoff value (0.12 µg/dL) by ROC analysis gave high sensitivity (93.8%) with somewhat improved specificity (58.3%). Both NSC and post DST SC levels were comparable between NFA, PA, and Pheo patients. In conclusion, our study revealed that measurements of NSC and/or post DST SC among patients with adrenal incidentaloma prove to have high sensitivities, but low specificities for the diagnosis of SCS from NFA, suggesting its possible alternative option before the screening tests for SCS currently employed in Japan.

Prolonged effects of intracerebroventricular angiotensin II on drinking, eating and locomotor behavior in mice.

The effects of centrally administered Angiotensin II (Ang II) on water and food intake in rodent models are well known. However, most studies have focused on the acute effects of intracranial Ang II. In the current study, we evaluated the effects of intracerebroventricular Ang II on food and water intake as well as locomotor activity over the entire dark phase of the murine diurnal cycle. Consistent with the previous reports, centrally administered Ang II rapidly stimulated water intake over the initial 1-hour period following treatment. However, this acute increase was immediately followed by a marked reduction in water intake resulting in decreased cumulative water intake approximately 7h after Ang II treatment. Pretreating animals with an Ang II type 1 receptor blocker, Losartan, completely antagonized the acute effect of Ang II and abolished initial water intake. In contrast, application of an Ang II type 2 receptor blocker, PD123319, abrogated the prolonged inhibitory effect of Ang II on drinking behavior and partially suppressed the initial increases in water intake. The suppressive effects of Ang II on cumulative food intake and spontaneous physical activity were also evident throughout the entire dark phase of diurnal cycle. These experiments are the first to suggest that the stimulatory effect of central Ang II treatment on water consumption is very temporary and that it causes a sustained suppressive effect on voluntary locomotion and food intake behavior in mice.

Differential expression of genes related to drug responsiveness between sparsely and densely granulated somatotroph adenomas.

There are two main subtypes of GH-producing pituitary adenoma: densely granulated (DG-type) and sparsely granulated (SG-type). Despite the difference in drug responsiveness between the two subtypes, their molecular mechanisms remain unknown. The aim of this study is to evaluate the differential expression of genes related to drug responsiveness between the two subtypes of somatotroph adenoma, and their relationship to the clinical characteristics. Eighty-two acromegaly patients (44 DG-type, 38 SG-type) were studied retrospectively. Clinical characteristics were compared between the two subtypes. Among them, 36 tumor tissue specimens (19 DG-type, 17 SG-type) were available for investigation of the expression of SSTR2, SSTR5 and D2R that are reported to be involved in drug responsiveness by realtime RT-PCR. Protein level was evaluated by immunohistochemical study. Patients with SG-type adenomas were younger in age and showed greater GH suppression by octreotide, but not by bromocriptin, and bigger in size and more invasiveness than DG-type adenomas. The mRNA expression of SSTR2 in DG-type adenomas were greater than those in SG-type adenomas and showed significantly positive correlation with GH suppression by octreotide. There was positive correlation between mRNA and protein levels of SSTR2. These data suggested that the differences of responsiveness to octreotide between DG- and SG-type adenomas are based on the expression levels of SSTR2.

Overexpression of receptor for advanced glycation end products induces monocyte chemoattractant protein-1 expression in rat vascular smooth muscle cell line.

AIM: The receptor for advanced glycation end-products (RAGE) has been suggested to play a pivotal role in the development of diabetic vasculopathy and atherosclerosis; however, due to its low expression, the physiological role of RAGE in vascular smooth muscle cells (VSMC) remains unknown. METHODS: Using VSMC lines stably expressing RAGE (RAGE-A10), we studied the molecular mechanism by which S100B, a RAGE ligand, induces proinflammatory gene expression. RESULTS: S100B induced NF-κB activation and the expression of several proinflammatory genes (MCP-1, IL-6, ICAM-1) at mRNA and protein levels in RAGE-A10, among which MCP-1 expression was the most robust. S100B-induced MCP-1 expression was dose-dependently blocked by inhibitors of JNK (SP600125), p38 (SB203580), MEK-1 (U0126) as well as NF-κB (Bay117085). In RAGE-A10, S100B activated JNK, MEK-1 and p38. S100B-induced MCP-1 promoter activity via NF-κB binding sites and nuclear translocation of NF-κB p65 subunit were blocked by SP600125, U0126, and SB203580 in RAGE-A10. CONCLUSION: Our study demonstrates that S100B increased MCP-1 expression via NF-κB and mitogen-activated protein kinase (JNK, ERK1/2, and p38) pathways in RAGE-overexpressed A10 cell lines. Thus, RAGE-A10 could be a useful cell model for studying the molecular mechanism(s) of up-regulated RAGE in the vasculature.