Clinical Features of Patients with an Epidermal Growth Factor Receptor T790M Mutation Detected in Circulating Tumor DNA.

BACKGROUND: Osimertinib, a third-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI), is effective against EGFR-mutated non-small cell lung carcinoma resistant to first- or second-generation EGFR-TKIs in patients in whom an EGFR T790M mutation has been detected. Detection of the T790M mutation using circulating tumor DNA (ctDNA) is less invasive than a tissue re-biopsy, including a transbronchial lung biopsy; however, the prognostic implications of the T790M mutation in ctDNA have not been fully elucidated. METHODS: We retrospectively reviewed the clinical features of non-small cell lung carcinoma patients in whom an EGFR T790M mutation had been detected at our hospital and assessed the clinical outcomes of osimertinib for these patients in terms of detection sites. RESULTS: An EGFR T790M mutation was detected in 32 non-small cell lung carcinoma patients, of whom 21 (65.6%) underwent osimertinib treatment after detection of the mutation. The mutation was detected using plasma samples in 10 patients (47.6%; liquid biopsy group), while it was detected using tissue samples in 11 patients (52.4%; tissue biopsy group). Liver and bone metastases were more frequently observed in patients in the liquid biopsy group than in the tissue biopsy group (30.0 vs. 0% and 60.0 vs. 18.2%, respectively). The median progression-free survival time was significantly shorter in the liquid biopsy group (132.0 days) than in the tissue biopsy group (682.0 days). The median overall survival time in the liquid biopsy group was 376.0 days, whereas that in the tissue biopsy group was not reached during our observation period. CONCLUSIONS: Non-small cell lung carcinoma patients in whom an EGFR T790M mutation was detected in plasma samples demonstrated a poorer response to osimertinib than those in whom the mutation was detected in tissue specimens.

[Seven-Year Follow-Up of Advanced Gastric Carcinoma Treated Only with Chemotherapy Considering the Macroscopic Findings].

A 75-year-old woman presented with difficulty in swallowing. Esophagogastroduodenoscopy(EGD)revealed a Borrmann type 3 advanced gastric cardia carcinoma. Computed tomography(CT)revealed three lymph node metastases, and thus, the preoperative diagnosis was cT4aN2M0, cStage ⅢB. However, the patient refused resection, and chemotherapy was initiated. The chemotherapy regimen was sequentially changed based on the macroscopic characteristics of the lesion: S-1 plus CDDP followed by S-1 alone, S-1 plus PTX, and PTX alone. We have continued to follow-upthe lesion using EGD and CT, and have observed the macroscopic characteristics of the advanced gastric carcinoma treated without resection for 7 years.

Structure of a dominant-negative helix-loop-helix transcriptional regulator suggests mechanisms of autoinhibition.

Helix-loop-helix (HLH) family transcription factors regulate numerous developmental and homeostatic processes. Dominant-negative HLH (dnHLH) proteins lack DNA-binding ability and capture basic HLH (bHLH) transcription factors to inhibit cellular differentiation and enhance cell proliferation and motility, thus participating in patho-physiological processes. We report the first structure of a free-standing human dnHLH protein, HHM (Human homologue of murine maternal Id-like molecule). HHM adopts a V-shaped conformation, with N-terminal and C-terminal five-helix bundles connected by the HLH region. In striking contrast to the common HLH, the HLH region in HHM is extended, with its hydrophobic dimerization interfaces embedded in the N- and C-terminal helix bundles. Biochemical and physicochemical analyses revealed that HHM exists in slow equilibrium between this V-shaped form and the partially unfolded, relaxed form. The latter form is readily available for interactions with its target bHLH transcription factors. Mutations disrupting the interactions in the V-shaped form compromised the target transcription factor specificity and accelerated myogenic cell differentiation. Therefore, the V-shaped form of HHM may represent an autoinhibited state, and the dynamic conformational equilibrium may control the target specificity.

Conditional ablation of HMGB1 in mice reveals its protective function against endotoxemia and bacterial infection.

High-mobility group box 1 (HMGB1) is a DNA-binding protein abundantly expressed in the nucleus that has gained much attention for its regulation of immunity and inflammation. Despite this, whether and how HMGB1 contributes to protective and/or pathological responses in vivo is unclear. In this study, we constructed Hmgb1-floxed (Hmgb1(f)(/f)) mice to achieve the conditional inactivation of the gene in a cell- and tissue-specific manner by crossing these mice with an appropriate Cre recombinase transgenic strain. Interestingly, although mice with HMGB1 ablation in myeloid cells apparently develop normally, they are more sensitive to endotoxin shock compared with control mice, which is accompanied by massive macrophage cell death. Furthermore, these mice also show an increased sensitivity to Listeria monocytogenes infection. We also provide evidence that the loss of HMGB1 in macrophages results in the suppression of autophagy, which is commonly induced by lipopolysaccharide stimulation or L. monocytogenes infection. Thus, intracellular HMGB1 contributes to the protection of mice from endotoxemia and bacterial infection by mediating autophagy in macrophages. These newly generated HMGB1 conditional knockout mice will serve a useful tool with which to study further the in vivo role of this protein in various pathological conditions.

Beneficial innate signaling interference for antibacterial responses by a Toll-like receptor-mediated enhancement of the MKP-IRF3 axis.

A major function of innate immune receptors is to recognize pathogen-associated molecular patterns and then evoke immune responses appropriate to the nature of the invading pathogen(s). Because innate immune cells express various types of these receptors, distinct combinations of signaling pathways are activated in response to a given pathogen. Although the conventional wisdom is that these signaling pathways cooperate with one another to ensure an effective host response, a more nuanced view recognizes antagonism between the individual pathways, where the attenuation of a signaling pathway(s) by others may shape the immune response. In this study, we show that, on Listeria monocytogenes infection, Toll-like receptor-triggered MyD88 signaling pathways suppress type I IFN gene induction, which is detrimental to macrophage bactericidal activity. These pathways target and suppress the IFN regulatory factor 3 (IRF3) transcription factor that is activated by the stimulator of IFN genes-TANK-binding kinase-1 kinase pathway. We also provide evidence for the involvement of the MAPK phosphatase family members, which renders IRF3 hypophosphorylated on Toll-like receptor signaling by enhancing the formation of an MAPK phosphatase-IRF3-TANK-binding kinase-1 ternary complex. This study, therefore, reveals a hitherto unrecognized and important contribution of a beneficial innate signaling interference against bacterial infections.

Oligodendrocyte transcription factor 1 (Olig1) is a Smad cofactor involved in cell motility induced by transforming growth factor-ß.

Transforming growth factor (TGF)-ß plays crucial roles in embryonic development and adult tissue homeostasis by eliciting various cellular responses in target cells. TGF-ß signaling is principally mediated through receptor-activated Smad proteins, which regulate expression of target genes in cooperation with other DNA-binding transcription factors (Smad cofactors). In this study, we found that the basic helix-loop-helix transcription factor Olig1 is a Smad cofactor involved in TGF-ß-induced cell motility. Knockdown of Olig1 attenuated TGF-ß-induced cell motility in chamber migration and wound healing assays. In contrast, Olig1 knockdown had no effect on bone morphogenetic protein-induced cell motility, TGF-ß-induced cytostasis, or epithelial-mesenchymal transition. Furthermore, we observed that cooperation of Smad2/3 with Olig1 is regulated by a peptidyl-prolyl cis/trans-isomerase, Pin1. TGF-ß-induced cell motility, induction of Olig1-regulated genes, and physical interaction between Smad2/3 and Olig1 were all inhibited after knockdown of Pin1, indicating a novel mode of regulation of Smad signaling. We also found that Olig1 interacts with the L3 loop of Smad3. Using a synthetic peptide corresponding to the L3 loop of Smad3, we succeeded in selectively inhibiting TGF-ß-induced cell motility. These findings may lead to a new strategy for selective regulation of TGF-ß-induced cellular responses.

Identification of age-dependent features of human bronchi using explainable artificial intelligence.

Background: Ageing induces functional and structural alterations in organs, and age-dependent parameters have been identified in various medical data sources. However, there is currently no specific clinical test to quantitatively evaluate age-related changes in bronchi. This study aimed to identify age-dependent bronchial features using explainable artificial intelligence for bronchoscopy images. Methods: The present study included 11 374 bronchoscopy images, divided into training and test datasets based on the time axis. We constructed convolutional neural network (CNN) models and evaluated these models using the correlation coefficient between the chronological age and the "bronchial age" calculated from bronchoscopy images. We employed gradient-weighted class activation mapping (Grad-CAM) to identify age-dependent bronchial features that the model focuses on. We assessed the universality of our model by comparing the distribution of bronchial age for each respiratory disease or smoking history. Results: We constructed deep-learning models using four representative CNN architectures to calculate bronchial age. Although the bronchial age showed a significant correlation with chronological age in each CNN architecture, EfficientNetB3 achieved the highest Pearson's correlation coefficient (0.9617). The application of Grad-CAM to the EfficientNetB3-based model revealed that the model predominantly attended to bronchial bifurcation sites, regardless of whether the model accurately predicted chronological age or exhibited discrepancies. There were no significant differences in the discrepancy between the bronchial age and chronological age among different respiratory diseases or according to smoking history. Conclusion: Bronchial bifurcation sites are universally important age-dependent features in bronchi, regardless of the type of respiratory disease or smoking history.

Glioma-initiating cells retain their tumorigenicity through integration of the Sox axis and Oct4 protein.

Although the concept of cancer stem cells or cancer-initiating cells had created a new paradigm for the treatment of malignant tumors, it remains unclear how cancer-initiating cells can be eradicated. We have previously reported that the transforming growth factor-ß (TGF-ß)-Sox4-Sox2 pathway is essential for glioma-initiating cells to retain their stemness, and inhibition of TGF-ß signaling may lead to differentiation of glioma-initiating cells (Ikushima, H., Todo, T., Ino, Y., Takahashi, M., Miyazawa, K., and Miyazono, K. (2009) Cell Stem Cell 5, 504-514). Here we demonstrate that Oct4 plays essential roles in retention of the stemness properties of glioma-initiating cells through positive regulation of Sox2 expression. We also show that, in glioma-initiating cells, Oct4 is associated with Sox4 and that Oct4-Sox4 complexes cooperatively activate the enhancer activity of the SOX2 gene. In contrast, in fetal neural progenitor cells, Sox2 expression is enhanced by transcriptional complex containing Sox2 protein itself, and this self-reinforcing loop of Sox2 appears to be disrupted in glioma-initiating cells, suggesting that Sox2 expression in glioma-initiating cells is differently regulated from that in neural progenitor cells. Our findings reveal differences between glioma-initiating cells and fetal neural progenitor cells and may open the way to depriving glioma-initiating cells of tumorigenic activity without affecting normal tissues.

RB1CC1 protein positively regulates transforming growth factor-beta signaling through the modulation of Arkadia E3 ubiquitin ligase activity.

Transforming growth factor-ß (TGF-ß) signaling is controlled by a variety of regulators, of which Smad7, c-Ski, and SnoN play a pivotal role in its negative regulation. Arkadia is a RING-type E3 ubiquitin ligase that targets these negative regulators for degradation to enhance TGF-ß signaling. In the present study we identified a candidate human tumor suppressor gene product RB1CC1/FIP200 as a novel positive regulator of TGF-ß signaling that functions as a substrate-selective cofactor of Arkadia. Overexpression of RB1CC1 enhanced TGF-ß signaling, and knockdown of endogenous RB1CC1 attenuated TGF-ß-induced expression of target genes as well as TGF-ß-induced cytostasis. RB1CC1 down-regulated the protein levels of c-Ski but not SnoN by enhancing the activity of Arkadia E3 ligase toward c-Ski. Substrate selectivity is primarily attributable to the physical interaction of RB1CC1 with substrates, suggesting its role as a scaffold protein. RB1CC1 thus appears to play a unique role as a modulator of TGF-ß signaling by restricting substrate specificity of Arkadia.

An Id-like molecule, HHM, is a synexpression group-restricted regulator of TGF-beta signalling.

Transforming growth factor (TGF)-beta induces various cellular responses principally through Smad-dependent transcriptional regulation. Activated Smad complexes cooperate with transcription factors in regulating a group of target genes. The target genes controlled by the same Smad-cofactor complexes are denoted a synexpression group. We found that an Id-like helix-loop-helix protein, human homologue of Maid (HHM), is a synexpression group-restricted regulator of TGF-beta signalling. HHM suppressed TGF-beta-induced growth inhibition and cell migration but not epithelial-mesenchymal transition. In addition, HHM inhibited TGF-beta-induced expression of plasminogen activator inhibitor-type 1 (PAI-1), PDGF-B, and p21(WAF), but not Snail. We identified a basic-helix-loop-helix protein, Olig1, as one of the Smad-binding transcription factors affected by HHM. Olig1 interacted with Smad2/3 in response to TGF-beta stimulation, and was involved in transcriptional activation of PAI-1 and PDGF-B. HHM, but not Id proteins, inhibited TGF-beta signalling-dependent association of Olig1 with Smad2/3 through physical interaction with Olig1. HHM thus appears to regulate a subset of TGF-beta target genes including the Olig1-Smad synexpression group. HHM is the first example of a cellular response-selective regulator of TGF-beta signalling with clearly determined mechanisms.

TGF-ß signal transduction spreading to a wider field: a broad variety of mechanisms for context-dependent effects of TGF-ß.

Transforming growth factor (TGF)-ß signaling is involved in almost all major cell behaviors under physiological and pathological conditions, and its regulatory system has therefore been vigorously investigated. The fundamental elements in TGF-ß signaling are TGF-ß ligands, their receptors, and intracellular Smad effectors. The TGF-ß ligand induces the receptors directly to phosphorylate and activate Smad proteins, which then form transcriptional complexes to control target genes. One of the classical questions in the field of research on TGF-ß signaling is how this cytokine induces multiple cell responses depending on cell type and cellular context. Possible answers to this question include cross-interaction with other signaling pathways, different repertoires of Smad-binding transcription factors, and genetic alterations, especially in cancer cells. In addition to these genetic paradigms, recent work has extended TGF-ß research into new fields, including epigenetic regulation and non-coding RNAs. In this review, we first describe the basic machinery of TGF-ß signaling and discuss several factors that comprise TGF-ß signaling networks. We then address mechanisms by which TGF-ß induces several responses in a cell-context-dependent fashion. In addition to classical frames, the interaction of TGF-ß signaling with epigenetics and microRNA is discussed.

Successful control of intestinal bleeding from metastasis of pulmonary pleomorphic carcinoma with pembrolizumab: A case report.

RATIONALE: Pulmonary pleomorphic carcinoma is a rare tumor with a poor prognosis and has no standard chemotherapy. We herein report a case of small intestinal metastasis of pulmonary pleomorphic carcinoma that resulted in intestinal bleeding and was successfully treated with pembrolizumab monotherapy. PATIENT CONCERNS: A 54-year-old man with a history of pulmonary pleomorphic carcinoma resection was referred to our hospital due to a 1-month history of a fever and general fatigue. DIAGNOSIS: Laboratory investigation revealed microcytic anemia. Hematochezia was also noted after admission. Computed tomography (CT) and positron emission tomography (PET)/CT at the time of this admission revealed intraperitoneal masses alongside the small intestine with no significant ascites. INTERVENTIONS: Pembrolizumab (400 mg/body) was introduced as the first-line chemotherapy. OUTCOMES: By the 15th day after the initial pembrolizumab administration, the fever had disappeared, and the intraperitoneal masses were markedly reduced. Hematochezia had also disappeared, and he no longer needed to receive blood transfusions. LESSONS: To our knowledge, this is the first report in which small intestinal metastasis of pulmonary pleomorphic carcinoma was successfully controlled by pembrolizumab monotherapy. Immune checkpoint inhibitors may be promising therapeutic agents against pulmonary pleomorphic carcinoma.

Multiple cerebral infarctions in ROS1-rearranged lung adenocarcinoma.

Rearrangements of specific tyrosine kinases are associated with an elevated risk of venous thrombosis in lung adenocarcinoma, although their effects on arterial thrombosis have not been fully elucidated. Here, we report two cases of ROS proto-oncogene 1 (ROS1)-rearranged lung adenocarcinoma with cerebral infarction during the peri-diagnostic period. Two cases took contrasting clinical courses: one patient could not receive targeted therapy because of a significant decline in performance status, whereas in the other patient, the performance status was maintained and targeted therapy drastically reduced the tumour size. Our cases suggest close monitoring could be considered in the selected cohort.

Cellular context-dependent "colors" of transforming growth factor-beta signaling.

Transforming growth factor (TGF)-beta signaling has interesting characteristics in the context of cancer. Although perturbations of TGF-beta signaling are strongly implicated in cancer progression, TGF-beta signaling has both tumor-suppressive and tumor-promoting effects. For example, TGF-beta inhibits cancer cell proliferation in some cellular contexts, but promotes it in others. Although several approaches to treating cancer have been considered using TGF-beta-based therapeutic strategies, the contradictory behaviors of TGF-beta have made these approaches complex. To put them to practical use, either the tumor-suppressive or tumor-promoting arm needs to be specifically manipulated. However, there is virtually no method to specifically regulate a certain cell response induced by TGF-beta. In this review, we first consider the basic machinery of TGF-beta signaling, and describe several cell responses induced by TGF-beta stimulation in specific contexts. Mechanisms by which TGF-beta can induce several responses in a cellular context-dependent fashion are discussed with established paradigms and models. We also address perspectives on the specific control of only a subset of numerous cell responses induced by TGF-beta stimulation. Such methods will aid specific regulation of either the tumor-suppressive or tumor-promoting arm of the TGF-beta pathway and in realization of TGF-beta-based treatment of malignant tumors.

Cisplatin plus pemetrexed therapy and subsequent immune checkpoint inhibitor administration for malignant peritoneal mesothelioma without pleural lesions: Case report.

RATIONALE: Malignant peritoneal mesothelioma is a rare tumor with a poor prognosis and has no recommended therapy after first-line pemetrexed and platinum-based chemotherapy. Moreover, effects of immune checkpoint inhibitors on peritoneal mesothelioma remains to be elucidated. We herein report the case of a 75-year-old man with peritoneal mesothelioma treated with cisplatin plus pemetrexed and subsequent nivolumab. PATIENT CONCERNS: A 75-year-old man was referred to our hospital due to lower abdominal pain. DIAGNOSIS: Positron emission tomography-computed tomography (CT) showed the accumulation of fluorodeoxyglucose in an intraperitoneal mass. A histological examination of a laparoscopic biopsy specimen revealed malignant peritoneal mesothelioma. INTERVENTIONS: After 4 cycles of cisplatin plus pemetrexed and 13 subsequent cycles of pemetrexed maintenance therapy showed beneficial responses until CT revealed liver metastasis. Nivolumab was then administered as the second-line therapy. OUTCOMES: After 3 cycles of biweekly nivolumab administration, he developed severe abdominal distention. CT revealed an intraperitoneal mass growing much more rapidly than ever, indicating hyperprogressive disease after nivolumab treatment. He ultimately died 51 days after the initial nivolumab administration. LESSONS: To our knowledge, this is the first report of hyperprogressive disease in a case of peritoneal mesothelioma after nivolumab treatment. While immune checkpoint inhibitors may be promising therapeutic strategies for treating malignant peritoneal mesothelioma, careful monitoring must be practiced with their application.

Crystallization and preliminary X-ray diffraction analysis of GCIP/HHM transcriptional regulator.

GCIP/HHM is a human nuclear protein that is implicated in regulation of cell proliferation. Its primary structure contains helix-loop-helix and leucine-zipper motifs but lacks a DNA-binding basic region. Native and selenomethionine-derivatized (SeMet) crystals of full-length GCIP/HHM were obtained using the hanging-drop vapour-diffusion method. The crystals were greatly improved by adding tris(2-carboxyethyl)phosphine as a reducing reagent and diffracted to 3.5 A resolution. Preliminary phase calculations using the data set obtained from the SeMet crystal suggested that the crystal belonged to space group P3(2)21 and contained one molecule per asymmetric unit. Structure determination by the multiple-wavelength anomalous dispersion method using the SeMet crystals is in progress.

Lung spindle cell carcinoma harbouring a constitutively active epidermal growth factor receptor mutation.

Lung spindle cell carcinoma is a rare lung tumour with a poor prognosis, and its standard therapy has not been established. Furthermore, little work has been conducted on the genetic characteristics of lung spindle cell carcinomas. Here, we report an 82-year-old woman who was referred to our hospital due to a fever and dyspnoea. Chest computed tomography demonstrated a 75-mm mass surrounded by infiltrates and atelectasis in the right upper lobe. She was eventually diagnosed with lung spindle cell carcinoma corresponding to clinical stage IVB (cT4N2M1c(ADR)). A genetic study indicated that epidermal growth factor receptor (EGFR) exon 19 was deleted in the tumour cells. She received gefitinib as first-line therapy. However, no significant effect was observed, and she died of respiratory failure 89 days after the initial admission. To our knowledge, this is the first case of spindle cell carcinoma of the lung in which a sensitizing EGFR mutation is detected.

Successful Treatment of Afatinib-Refractory Non-Small Cell Lung Cancer with Uncommon Complex EGFR Mutations Using Pembrolizumab: A Case Report.

Although there has been significant progress in immune-checkpoint inhibitor (ICI) treatment, it remains controversial whether they should be used in the treatment of epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC). We herein report the case of an NSCLC patient with uncommon complex EGFR mutations (G719S and L861Q) who was refractory to afatinib treatment but who showed a good response to pembrolizumab treatment. A 65-year-old female ex-smoker was diagnosed with right upper lobe NSCLC (clinical stage IVB; cT2bN3M1c). She had received afatinib for two months, but her disease showed rapid progression. Pembrolizumab treatment was initiated because more than 75% of her tumor cells expressed PD-L1. Her tumor responded well to pembrolizumab treatment and it remained effective for more than 1 year. Our case suggests that pembrolizumab treatment is a treatment option for NSCLC patients with uncommon EGFR mutations and high PD-L1 expression levels who are refractory to EGFR-TKI treatment.

Severe pleuritis and pericarditis associated with very-late-onset systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a multisystem disorder, which occurs mostly in young women. However, late-onset SLE does exist and sometimes presents with an atypical, diversified course. We describe an 85-year-old woman who was admitted to our hospital for lower extremity edema and hand grip weakness. Chest computed tomography scan 4 days after admission demonstrated rapid accumulation of pleural and pericardial effusions, which did not exist on admission. She was diagnosed with pleuritis and pericarditis associated with very-late-onset SLE. Methylprednisolone pulse therapy resulted in a drastic improvement in serositis. Our case exemplifies the fact that patients with late-onset SLE sometimes follow an atypical course, which makes the clinical diagnosis difficult.