Mirror-Image Human Serum Albumin Domain III as a Tool for Analyzing Site II-Dependent Molecular Recognition.

Human serum albumin (HSA) as a drug carrier can significantly improve the pharmacokinetic profiles of short-lived therapeutics. Conjugation of albumin-binding moieties (ABMs) to therapeutic agents may prolong their serum half-life by promoting their association with endogenous HSA. To discover a new molecular class of ABMs from mirror-image chemical space, a preparation protocol for bioactive HSA domain III and its d-enantiomer (d-HSA domain III) was established. Structural and functional analyses suggested that the synthetic protein enantiomers exhibited mirror-image structures and stereoselective neonatal fragement crystallizable receptor (FcRn) recognition. Additionally, the ligand-binding properties of synthetic l-HSA domain III were comparable with those of site II in native HSA, as confirmed using site II-selective fluorescent probes and an esterase substrate. Synthetic d-HSA domain III is an attractive tool for analyzing the site II-dependent molecular recognition properties of HSA.

Synthetic studies on the extracellular domain of the T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) using Trt-K10 solubilizing tags.

The T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) is an inhibitory immunoreceptor expressed on lymphocytes that serves as a promising target for cancer immunotherapy. In this study, facile synthetic protocols to produce the extracellular domain of TIGIT were investigated for applications of TIGIT in mirror-image screening. During the synthesis via sequential native chemical ligations, we encountered problems with significantly poor solubility of the ligated products. Introducing trityl-type solubilizing auxiliaries, which also functioned as temporary protecting groups for cysteine residues, facilitated a flexible order of ligations and efficient purification protocols. After refolding under appropriate conditions, the synthetic TIGIT showed a sufficient affinity toward its target ligand CD155.

Development of Mirror-Image Screening Systems for XIAP BIR3 Domain Inhibitors.

The X-linked inhibitor of apoptosis protein baculovirus IAP repeat (XIAP BIR3) domain is a promising therapeutic target for cancer treatment. For the mirror-image screening campaign to identify drug candidates from an unexplored mirror-image natural product library, a facile synthetic protocol for XIAP BIR3 domain synthesis was established by a native chemical ligation strategy using conserved cysteines present among BIR domains. The native and mirror-image XIAP BIR3 domains with an appropriate functional group for labeling were prepared using the established protocol. Taking advantage of the resulting synthetic proteins, several bioassay systems were developed to characterize inhibitors of the protein-protein interaction between the XIAP BIR3 domain and the second mitochondria-derived activator of caspases.

A Video App for Screening Osgood-Schlatter Disease Using Soccer Instep Kicking Motion Analysis.

BACKGROUND: Osgood-Schlatter disease (OSD) is a type of osteochondrosis and traction apophysitis that results from repeated contractions of the quadriceps femoris muscle on the tibial tuberosity. Its prevention, early diagnosis, and treatment are crucial because it causes chronic knee pain and surgical approaches are required if left untreated. Three-dimensional motion analysis is a useful approach for elucidating the pathological factors of OSD; however, it requires advanced cameras, sophisticated facilities, and expensive software. Conversely, the advent of technology has provided affordable video recording devices, and smartphone/tablet-based applications have enabled two-dimensional (2D) motion analysis. This emerging tool and artificial intelligence technology were used to analyze the pivot leg from videos recorded on a tablet device during the instep kicks of adolescent soccer players. Therefore, in this study, we aimed to determine whether the pathological factors for OSD occurring in the pivot foot can be identified through a simple 2D motion analysis using a tablet device. METHODS: In total, 94 knees of 47 soccer players (aged 14.1±0.8 years, all male) who belong to a single soccer club were evaluated. OSD was diagnosed using ultrasonography and physical examination (a positive bone fragment on ultrasonography or tenderness at the tibial tuberosity). Lower limb muscle tightness was evaluated using the finger-floor distance, straight leg raising test, heel-buttock distance, Thomas test, and ankle range of motion using a goniometer. We then performed motion analysis, and the instep kicking motion was recorded using a video camera on a tablet device. The joint angles of the hip, knee, and ankle were measured using a real-time human-pose detection system. Data were compared between the OSD and non-OSD groups. RESULTS: Overall, six of the 47 players (12.8%) were diagnosed with OSD. No correlation was found between lower limb tightness and the occurrence of OSD in all indices. However, the 2D motion analysis revealed that the knee flexion angle at the time of plantar placement during the instep kick movement was significantly larger in the OSD group than in the non-OSD group (OSD group: 42.0±7.2˚, non-OSD group: 33.5±6.6˚, *p=0.013). CONCLUSION:  A video motion analysis revealed that the knee flexion angle during the instep kicking motion was significantly greater in athletes with OSD of the supporting foot.

Inhibition of PTPN3 Expressed in Activated Lymphocytes Enhances the Antitumor Effects of Anti-PD-1 Therapy in Head and Neck Cancer, Especially in Hypoxic Environments.

In the tumor microenvironment, wherein cytotoxic lymphocytes interact with cancer cells, lymphocyte exhaustion, an immune checkpoint inhibitor target, is promoted. However, the efficacy of these inhibitors is limited, and improving response rates remains challenging. We previously reported that protein tyrosine phosphatase nonreceptor type (PTPN) 3 is a potential immune checkpoint molecule for activated lymphocytes and that PTPN3 inhibition should be a focus area for cancer immunotherapy development. Therefore, in this study, we focused on PTPN3-suppressive therapy in terms of lymphocyte exhaustion under hypoxic conditions, which are a cancer microenvironment, and investigated measures for improving the response to anti-programmed death receptor (PD)-1 antibody drugs. We found that PTPN3 expression was upregulated in activated lymphocytes under hypoxic conditions, similar to the findings for other immune checkpoint molecules, such as PD-1, T cell immunoglobulin mucin-3, and lymphocyte-activation gene-3; furthermore, it functioned as a lymphocyte exhaustion marker. In addition, PTPN3-suppressed activated lymphocytes promoted the mammalian target of rapamycin (mTOR)-Akt signaling pathway activation and enhanced proliferation, migration, and cytotoxic activities under hypoxic conditions. Furthermore, PTPN3 suppression in activated lymphocytes increased PD-1 expression and enhanced the antitumor effects of anti-PD-1 antibody drugs against head and neck cancer in vitro and in vivo. These results suggest that the suppression of PTPN3 expression in activated lymphocytes enhances the therapeutic effect of anti-PD-1 antibody drugs in head and neck cancer, especially under hypoxic conditions that cause lymphocyte exhaustion.

C4orf47 Contributes to the Induction of Stem-like Properties in Gallbladder Cancer Under Hypoxia.

BACKGROUND/AIM: Gallbladder cancer (GBC) is a refractory cancer with poor prognosis. Recently, therapy targeting the tumor microenvironment (TME) has gained attention. Cancer hypoxia is a significant factor in the tumor microenvironment (TME). Our research has shown that hypoxia activates several molecules and signaling pathways that contribute to the development of various types of cancer. Our analysis indicated that C4orf47 expression was up-regulated in a hypoxic environment and had a role in the dormancy of pancreatic cancer. There are no other reports on the biological significance of C4orf47 in cancer and its mechanism is still unknown. This study analyzed how C4orf47 affects refractory GBC to develop a new effective therapy for GBC. MATERIALS AND METHODS: Two human gallbladder carcinomas were used to examine how C4orf47 affects proliferation, migration, and invasion. C4orf47 was silenced using C4orf47 siRNA. RESULTS: C4orf47 was over-expressed in gallbladder carcinomas under hypoxic conditions. C4orf47 inhibition increased the anchor-dependent proliferation and decreased the anchor-independent colony formation of GBC cells. C4orf47 inhibition reduced epithelial-mesenchymal transition and suppressed migration and invasiveness of GBC cells. C4orf47 inhibition decreased CD44, Fbxw-7, and p27 expression and increased C-myc expression. CONCLUSION: C4orf47 enhanced invasiveness and CD44 expression, and reduced anchor-independent colony formation, suggesting that C4orf47 is involved in plasticity and the acquisition of the stem-like phenotype of GBC. This information is useful for the development of new therapeutic strategies for GBC.

Design and Synthesis of Monobody Variants with Low Immunogenicity.

Mirror-image proteins (d-proteins) are promising scaffolds for drug discovery because of their high proteolytic stability and low immunogenic properties. Facile and reproducible processes for the preparation of functional d-proteins are required for their application in therapeutic biologics. In this study, we designed and synthesized a novel monobody variant with two cysteine substitutions that facilitate the synthetic process via sequential native chemical ligations and improve protein stability by disulfide bond formation. The synthetic anti-GFP monobody in this model study exhibited good binding affinity to the target enhanced green fluorescent protein. In vivo administration of the synthetic anti-GFP monobody (l-monobody) to mice induced antidrug antibody (ADA) production, whereas no ADA production was observed following immunization with the mirror-image anti-GFP monobody (d-monobody). These results suggest that the synthetic d-monobody is a non-antibody protein scaffold with low immunogenic properties.

PTPN3 inhibition contributes to the activation of the dendritic cell function to be a promising new immunotherapy target.

PURPOSE: In a previous study, protein tyrosine phosphatase non-receptor type (PTPN) 3 was identified as an immune checkpoint molecule in lymphocytes, and its potential as a novel target for cancer immunotherapy was anticipated. However, evaluation of dendritic cell (DC) function as antigen-presenting cells is critical for the development of immunotherapy. In this study, we aimed to analyze the biological effect of PTPN3 on DCs induced from human peripheral blood monocytes obtained from healthy individuals. METHODS: We used short-interfering RNA to knock down PTP3 in DCs. For DC maturation, we added cancer cell lysate and tumor necrosis factor-α/interferon-α to immature DCs. In the cytotoxic assay, the target cancer cells were SBC5, unmatched with DCs from healthy human leukocyte antigen (HLA)-A24, or Sq-1, matched with DCs. Enzyme-linked immunosorbent assay was used to determine the amount of cytokines. To examine the intracellular signaling system, intracellular staining was used. RESULTS: PTPN3 knockdown significantly increased the number of DCs, expression of CD80 and chemokine receptor (CCR)7, and production of interleukin-12p40/p70 in mature DCs. In the HLA-A24-restricted DC and human lung squamous cell carcinoma cell cytotoxic assay, inhibition of PTPN3 expression in mature DCs induced cytotoxic T lymphocytes with increased production of INF-γ and granzyme B, and enhanced toxicity against cancer cells and migration to cancer. Furthermore, inhibition of PTPN3 expression activated the mitogen-activated protein kinase pathway in DCs. CONCLUSION: Based on our findings, inhibition of PTPN3 expression could contribute to the development of novel cancer immunotherapies that activate not only lymphocytes but also DCs.

C4orf47 contributes to the dormancy of pancreatic cancer under hypoxic conditions.

In our comprehensive analysis of pancreatic cancer pathology, we found that the C4orf47 molecule was upregulated in hypoxic environments. C4orf47 is reported to be a centrosome-associated protein, but its biological significance in cancer is completely unknown; therefore, we assessed its role in pancreatic cancer. We found that C4orf47 was a direct target of HIF-1α and is upregulated in hypoxic conditions, in which it suppressed the cell cycle and inhibits cell proliferation through up-regulation of the cell cycle repressors Fbxw-7, P27, and p57; and the down-regulation of the cell cycle promoters c-myc, cyclinD1, and cyclinC. Furthermore, C4orf47 induced epithelial-mesenchymal transition and enhanced their cell plasticity and invasiveness. In addition, the p-Erk/p-p38 ratio was significantly enhanced and down-regulated CD44 expression by C4orf47 suppression, suggesting that C4orf47 is involved in pancreatic cancer dormancy under hypoxic conditions. Furthermore, the potential of C4orf47 expression was a good prognostic biomarker for pancreatic cancer. These results contribute to the elucidation of the pathology of refractory pancreatic cancer and the development of novel therapeutic strategies.

Tropomyosin-related Kinase B Is Potentially a Biomarker of Prognosis and Therapeutic Target for Malignant Thymic Epithelial Tumors.

BACKGROUND/AIM: Thymic epithelial tumors (TETs) mainly consist of thymoma and thymic carcinoma. Complete surgical resection is vital for the successful management of these TETs, and adjuvant therapy such as systematic chemotherapy and/or radiotherapy plays important roles in the management of recurrent or metastasized disease. However, there is still a lack of a standard treatment after the failure of these adjuvant therapies. There is thus a need to develop molecular targeted therapies for advanced malignant TETs. In the present study, we evaluated the biological significance of brain-derived neurotrophic factor (BDNF)/tropomyosin receptor kinase B (TrkB) signaling for TETs. MATERIALS AND METHODS: The expression of TrkB in 48 formalin-fixed, paraffin-embedded TET specimens (43 thymoma and 5 thymic carcinoma) collected by surgical resection was evaluated immunohistochemically. A thymic carcinoma cell line was evaluated for the role of BDNF/TrkB signaling pathway in an in vitro assay. RESULTS: High TrkB expression was related to significantly poor prognosis in patients with TETs. In vitro experiments showed that BDNF/TrkB signaling was involved in the proliferation of Ty-82 cells, but not their invasion and migration. CONCLUSION: TrkB expression is a biomarker of the prognosis for TETs and the BDNF/TrkB signaling pathway is potentially a new therapeutic target for mTETs.

Correlation Between Smoking Status and Short-term Outcome of Thoracoscopic Surgery for Lung Cancer.

BACKGROUND: Smoking has a major role in the risk of postoperative pulmonary complications. This study aimed to elucidate the correlation between smoking status and pulmonary complications after thoracoscopic surgery for lung cancer. METHODS: A total of 1751 patients who underwent thoracoscopic lobectomy or segmentectomy for lung cancer between April 2011 and March 2020 were assessed. The rate of pulmonary complications was evaluated according to smoking status and preoperative duration of smoking cessation. Univariate and multivariate logistic regression analyses were performed. RESULTS: Pulmonary complications were observed in 50 patients (2.9%), whereas 3 (0.2%) died within 90 days of surgery. The rate of pulmonary complications was higher in smokers than in nonsmokers (4.6% vs 0.9%; P < .001), and smoking history was an independent risk factor for pulmonary complications (odds ratio, 3.31; P = .007). The complication rate in patients with a cessation period of more than 2 months was significantly lower than that in patients who ceased smoking within 2 months (4.0% vs 8.5%; P = .043), but it was still higher than that in nonsmokers (4.0% vs 0.9%; P < .001). In the multivariable analysis for smokers, preoperative short-term smoking cessation within 2 months, male sex, histologic type, tumor size, and cardiopulmonary comorbidities were associated with pulmonary complications instead of pack-year smoking history. CONCLUSIONS: Smoking habits and preoperative smoking cessation were independently associated with pulmonary complications after thoracoscopic surgery for lung cancer. A preoperative smoking cessation period of 2 months or more is preferable for reducing the risk of such complications.

Positive bag lavage cytology during thoracoscopic surgery for lung cancer is a significant predictor of locoregional recurrence.

OBJECTIVES: Advances in thoracoscopic surgery have made skin incisions smaller, but there are concerns about cancer cell contamination during sample extraction. We performed retrieval bag lavage cytology (BLC) during thoracoscopic surgery to evaluate the risk of cancer dissemination and the prognostic influence of BLC status. METHODS: BLC was investigated in 893 patients who underwent thoracoscopic lobectomy or segmentectomy for lung cancer between 2013 and 2018. The clinicopathological features and prognosis were compared between the BLC-positive and BLC-negative groups. RESULTS: Forty-nine patients (5.5%) were positive for BLC. BLC correlated with pleural invasion (49.0% vs. 12.9%, P < 0.001); however, BLC was positive in 3.3% of cases without pleural invasion. Multivariate analysis revealed that tumor size, lymph node metastasis, lymphatic and pleural invasion were predictive factors for positive BLC. Prognosis was poorer in the BLC-positive group than in the BLC-negative group (5-year overall survival, 73.6% vs. 90.2%, P < 0.001); nevertheless, positive BLC was not an independent prognostic factor. The locoregional recurrence rate was higher among BLC-positive patients than among BLC-negative patients, whereas there was no significant difference in the distant recurrence rate. Positive BLC was associated with locoregional recurrence (hazard ratio 1.87, P = 0.044) and the correlation was stronger in stage I lung cancer. There were no cases of extraction bag breakage or port-site recurrence. CONCLUSIONS: BLC positivity was correlated with the risk of locoregional recurrence in patients with surgically resected lung cancer, although it was not an independent prognostic factor. Careful manipulation is essential for extracting specimens from the thoracic cavity.

PTPN3 Could Βe a Therapeutic Target of Pancreatic Cancer.

BACKGROUND/AIM: Recently, protein tyrosine phosphatase non-receptor type 3 (PTPN3) has gained attention. However, the role of PTPN3 in cancer has not been fully elucidated. In the present study, we analyzed the role of PTPN3 in pancreatic cancer and investigated whether PTPN3 could be a new therapeutic target for pancreatic cancer. MATERIALS AND METHODS: Two pancreatic ductal adenocarcinoma (PDAC) cell lines were used as target cells. Cell proliferation was investigated using cell counting and a xenograft mouse model. Migration and invasion were analyzed using Transwell inserts. Activation-related signaling molecules were examined by western blotting. RESULTS: PTPN3 contributes to the proliferation, migration, and invasion of PDAC cells in vitro. PTPN3 promotes tumor growth in a mouse xenograft model, an action mediated partially through the MAPK pathway. CONCLUSION: PTPN3 could be a new therapeutic target for pancreatic cancer.

The utility of three-dimensional computed tomography for prediction of tumor invasiveness in clinical stage IA lung adenocarcinoma.

BACKGROUND: It is critical to have an accurate measurement of solid tumor size in order to predict the invasiveness of small lung adenocarcinomas. Some lesions cannot be measured accurately via High-resolution computed tomography (HRCT) due to their irregular shape and unclear borders. For this reason, we evaluated the relative efficacy of three-dimensional (3D) CT for predicting invasive adenocarcinoma. METHODS: We evaluated 195 patients with clinical stage IA adenocarcinomas, including 109 with lesions documented as invasive that were surgically resected at our institute during 2017. All lesions were categorized as either (I) lesions that were difficult to evaluate (i.e., hazy lesions; HL) or (II) more typical lesions (TL). The relationships between solid tumor size as determined by HRCT, solid tumor volume as determined by 3D CT and pathologic diagnosis were evaluated. RESULTS: Fifty-seven patients (29%) were diagnosed with HL. We set the cut-off value for the solid volume at 225 mm3 as predictive for invasive adenocarcinoma. When evaluating all 195 patients as a group, the accuracy, sensitivity, and specificity based on the solid tumor volume were similar to those based on the solid tumor size. When we limit our analysis to the HL group, the specificity based on solid tumor volume (65.5%) was higher than that based on solid tumor size (44.8%) with a difference that approached statistical significance (P=0.070). CONCLUSIONS: 3D CT was equivalent to HRCT for predicting invasive adenocarcinoma and may be particularly useful for diagnosing lesions that are difficult to evaluate on HRCT.

An extremely rare case of rapidly growing mediastinal well-differentiated liposarcoma with a sclerosing variant: a case report.

BACKGROUND: Liposarcoma arising from the mediastinum is rare, accounting for less than 1% of mediastinal tumors. Furthermore, a rapidly growing well-differentiated liposarcoma is extremely rare. A well-differentiated liposarcoma is usually considered a low-grade malignancy. However, we present an extremely rare case of a sclerosing variant of well-differentiated liposarcoma that grew rapidly within a year. CASE PRESENTATION: A 77-year-old man with a giant mass in the left thoracic cavity was referred to our hospital. This mass measured about 10 cm and occupied the left-sided mediastinum on a chest radiography; however, there was no abnormal finding on the previous year's chest radiography. Chest-enhanced computed tomography revealed a well-circumscribed 11-cm mass in the left-sided anterior mediastinum. Positron emission tomography showed accumulation of fluorodeoxyglucose uptake in this tumor (maximum standard uptake value = 3.3). The radiological findings of computed tomography and positron emission tomography indicated that this tumor was a benign or low-grade malignancy; therefore, the chest radiographic findings were difficult to explain. To explain this discrepancy and establish the diagnosis, tumor resection was performed via left posterolateral thoracotomy. Intraoperatively, the left phrenic nerve and pericardium were adhered tightly to the tumor, so we resected them. The tumor was well-circumscribed and fibrous; therefore, the initial diagnosis was solitary fibrous tumor. However, based on its histopathological and immunohistochemical patterns, the tumor was diagnosed as a sclerosing variant of well-differentiated liposarcoma. Five years postoperatively, the patient remains alive with no evidence of disease recurrence. CONCLUSIONS: A well-differentiated liposarcoma is usually considered a low-grade malignancy. Nevertheless, the giant tumor in the present case appeared within 1 year. Thus, this was an extremely rare case of a sclerosing variant of well-differentiated liposarcoma with rapid growth.

A rapidly growing mature mediastinal teratoma with a testicular epidermoid cyst and familial Mediterranean fever.

Anterior mediastinal teratomas are common and are generally characterized as slow growing tumors. Very few reports documenting rapidly growing tumors exist. Here, we describe a case of a mature teratoma showing rapid growth in 1 year treated with complete surgical resection.