Conserved class B GPCR activation by a biased intracellular agonist.

Class B G-protein-coupled receptors (GPCRs), including glucagon-like peptide 1 receptor (GLP1R) and parathyroid hormone 1 receptor (PTH1R), are important drug targets1-5. Injectable peptide drugs targeting these receptors have been developed, but orally available small-molecule drugs remain under development6,7. Here we report the high-resolution structure of human PTH1R in complex with the stimulatory G protein (Gs) and a small-molecule agonist, PCO371, which reveals an unexpected binding mode of PCO371 at the cytoplasmic interface of PTH1R with Gs. The PCO371-binding site is totally different from all binding sites previously reported for small molecules or peptide ligands in GPCRs. The residues that make up the PCO371-binding pocket are conserved in class B GPCRs, and a single alteration in PTH2R and two residue alterations in GLP1R convert these receptors to respond to PCO371. Functional assays reveal that PCO371 is a G-protein-biased agonist that is defective in promoting PTH1R-mediated arrestin signalling. Together, these results uncover a distinct binding site for designing small-molecule agonists for PTH1R and possibly other members of the class B GPCRs and define a receptor conformation that is specific only for G-protein activation but not arrestin signalling. These insights should facilitate the design of distinct types of class B GPCR small-molecule agonist for various therapeutic indications.

Impact of deep muscle invasion on nodal status and survival in patients with pT2 esophageal squamous cancer.

BACKGROUND: Whether T2 esophageal squamous cell carcinoma should be subclassified remains controversial. We aimed to investigate the impact of the depth of muscularis propria invasion on nodal status and survival outcomes. METHODS: We identified patients with pT2 esophageal squamous cell carcinoma who underwent primary surgery from January 2009 to June 2017. Clinical data were extracted from prospectively maintained databases. Tumor muscularis propria invasion was stratified into superficial or deep. Binary logistic regression was used to determine risk factors for lymph node metastases. The impact of the depth of muscularis propria invasion on survival was investigated using Kaplan‒Meier analysis and a Cox proportional hazard regression model. RESULTS: A total of 750 patients from three institutes were investigated. The depth of muscularis propria invasion (odds ratio [OR]: 3.95, 95% confidence interval [CI]: 2.46-6.35; p < 0.001) was correlated with lymph node metastases using logistic regression. T substage (hazard ratio [HR]: 1.37, 95% CI: 1.05-1.79; p < 0.001) and N status (HR: 1.51, 95% CI: 1.05-2.17; p < 0.001) were independent risk factors in multivariate Cox regression analysis. The deep muscle invasion was associated with worse overall survival (HR: 1.52, 95% CI: 1.19-1.94; p = 0.001) than superficial, specifically in T2N0 patients (HR: 1.38, 95% CI: 1.08-1.94; p = 0.035). CONCLUSIONS: We found that deep muscle invasion was associated with significantly worse outcomes and recommended the substaging of pT2 esophageal squamous cell carcinoma in routine pathological examination.

Melatonin ameliorates 10-hydroxycamptothecin-induced oxidative stress and apoptosis via autophagy-regulated p62/Keap1/Nrf2 pathway in mouse testicular cells.

10-Hydroxycamptothecin (HCPT) is a widely used clinical anticancer drug but has a significant side effect profile. Melatonin has a beneficial impact on the chemotherapy of different cancer cells and reproductive processes, but the effect and underlying molecular mechanism of melatonin's involvement in the HCPT-induced side effects in cells, especially in the testicular cells, are poorly understood. In this study, we found that melatonin therapy significantly restored HCPT-induced testicular cell damage and did not affect the antitumor effect of HCPT. Further analysis found that melatonin therapy suppressed HCPT-induced DNA damage associated with ataxia-telangiectasia mutated- and Rad3-related and CHK1 phosphorylation levels in the testis. Changes in apoptosis-associated protein levels (Bax, Bcl-2, p53, and Cleaved caspase-3) and in reactive oxygen species-associated proteins (Nrf2 and Keap1) and index (malondialdehyde and glutathione) suggested that melatonin treatment relieved HCPT-induced cell apoptosis and oxidative damage, respectively. Mechanistically, melatonin-activated autophagy proteins (ATG7, Beclin1, and LC3bII/I) may induce p62-dependent autophagy to degrade Keap1, eliciting Nrf2 from Keap1-Nrf2 interaction to promote antioxidant enzyme expression such as HO-1, which would salvage HCPT-induced ROS production and mitochondrial dysfunction. Collectively, this study reveals that melatonin therapy may protect testicular cells from HCPT-induced damage via the activation of autophagy, which alleviates oxidative stress, mitochondrial dysfunction, and cell apoptosis.

MTHFD1L confers a poor prognosis and malignant phenotype in esophageal squamous cell carcinoma by activating the ERK5 signaling pathway.

MTHFD1L, a key enzyme of folate metabolism, is seldom reported in cancer. In this study, we investigate the role of MTHFD1L in the tumorigenicity of esophageal squamous cell carcinoma (ESCC). ESCC tissue microarrays (TMAs) containing 177 samples from 109 patients were utilized to evaluate whether MTHFD1L expression, determined using immunohistochemical analysis, is a prognostic indicator for ESCC patients. The function of MTHFD1L in the migration and invasion of ESCC cells was studied with wound healing, Transwell, and three-dimensional spheroid invasion assays in vitro and a lung metastasis mouse model in vivo. The mRNA microarrays and Ingenuity pathway analysis (IPA) were used to explore the downstream of MTHFD1L. Elevated expression of MTHFD1L in ESCC tissues was significantly associated with poor differentiation and prognosis. These phenotypic assays revealed that MTHFD1L significantly promote the viability and metastasis of ESCC cell in vivo and in vitro. Further detailed analyses of the molecular mechanism demonstrated that the ESCC progression driven by MTHFD1L was through up-regulation ERK5 signaling pathways. These findings reveal that MTHFD1L is positively associated with the aggressive phenotype of ESCC by activating ERK5 signaling pathways, suggesting that MTHFD1L is a new biomarker and a potential molecular therapeutic target for ESCC.

Mapping of lymph node metastasis from esophageal squamous cell carcinoma after neoadjuvant treatment: a prospective analysis from a high-volume institution in China.

The study aimed to describe the prevalence of lymph node metastases per lymph node station for esophageal squamous cell carcinoma (ESCC) after neoadjuvant treatment. Clinicopathological variables of ESCC patients were retrieved from the prospective database of the Surgical Esophageal Cancer Patient Registry in West China Hospital, Sichuan University. A two-field lymphadenectomy was routinely performed, and an extensive three-field lymphadenectomy was performed if cervical lymph node metastasis was suspected. According to AJCC/UICC 8, lymph node stations were investigated separately. The number of patients with metastatic lymph nodes divided by those who underwent lymph node dissection at that station was used to define the percentage of patients with lymph node metastases. Data are also separately analyzed according to the pathological response of the primary tumor, neoadjuvant treatment regimens, pretreatment tumor length, and tumor location. Between January 2019 and March 2023, 623 patients who underwent neoadjuvant therapy followed by transthoracic esophagectomy were enrolled. Lymph node metastases were found in 212 patients (34.0%) and most frequently seen in lymph nodes along the right recurrent nerve (10.1%, 58/575), paracardial station (11.4%, 67/587), and lymph nodes along the left gastric artery (10.9%, 65/597). For patients with pretreatment tumor length of >4 cm and non-pathological complete response of the primary tumor, the metastatic rate of the right lower cervical paratracheal lymph nodes is 10.9% (10/92) and 10.6% (11/104), respectively. For patients with an upper thoracic tumor, metastatic lymph nodes were most frequently seen along the right recurrent nerve (14.2%, 8/56). For patients with a middle thoracic tumor, metastatic lymph nodes were most commonly seen in the right lower cervical paratracheal lymph nodes (10.3%, 8/78), paracardial lymph nodes (10.2%, 29/285), and lymph nodes along the left gastric artery (10.4%, 30/289). For patients with a lower thoracic tumor, metastatic lymph nodes were most frequently seen in the paracardial station (14.2%, 35/247) and lymph nodes along the left gastric artery (13.1%, 33/252). The study precisely determined the distribution of lymph node metastases in ESCC after neoadjuvant treatment, which may help to optimize the extent of lymphadenectomy in the surgical management of ESCC patients after neoadjuvant therapy.

Limited-stage small cell carcinoma of the esophagus treated with curative esophagectomy: A multicenter retrospective cohort study.

BACKGROUND: This study aimed to investigate the efficacy of surgery in the treatment of small cell carcinoma of the esophagus (SCCE) and explore potential prognostic factors. METHODS: We screened patients with SCCE who underwent esophagectomy from 2010 to 2018 at three institutes. Differences in survival were analyzed using the Kaplan-Meier method and log-rank test. The prognostic factors were identified using univariate and multivariate analyses. RESULTS: A total of 69 patients were included. Multivariate analysis showed that TNM stage (hazard ratio [HR]: 4.10, 95% confidence interval [CI]: 1.57-10.75, p = 0.004) and adjuvant therapy (HR: 0.28, 95% CI: 0.16-0.51, p < 0.001) were independent prognostic factors. Stage I, stage IIA, and stage IIB disease were merged into the surgery response disease (SRD), whereas stage III disease into the surgery nonresponse disease (SNRD). The SRD group had significantly improved survival compared to the SNRD group (HR: 0.33, 95% CI: 0.19-0.58, p < 0.001). In addition, adjuvant therapy increased survival benefit in the SNRD group (p < 0.001) but not in the SRD group (p = 0.061). CONCLUSIONS: Surgery alone appears to be adequate for disease control in the SRD group, whereas multimodality therapy was associated with improved survival in the SNRD group.

A rare Bochdalek hernia in an adult: a case report.

BACKGROUND: Symptomatic Bochdalek hernias are found mainly in infants in respiratory distress and occur rarely in adults. CASE PRESENTATION: We report a rare case of Bochdalek hernia associated with developmental abnormalities in an adult who exhibited acute chest pain and dyspnea on exertion. CONCLUSIONS: This case highlights the importance of the differential diagnosis of acute left-sided chest pain and antenatal examination.

Mendelian randomization analysis of atopic dermatitis and esophageal cancer in East Asian and European populations.

Background: Emerging observational studies showed an association between atopic dermatitis (AD) and gastrointestinal cancers. However, it remains unclear whether this association is causal, particularly in the case of cancers like esophageal cancer, which exhibit ancestral genetic traits. Methods: To assess the potential causal relationship between AD and esophageal cancer across diverse ancestral backgrounds, we conducted a 2-sample Mendelian randomization study. Independent genetic instruments for AD from the FinnGen consortium (N case = 7024 and N control = 198 740), BioBank Japan (N case = 2385 and N control = 209 651) and Early Genetics and Lifecourse Epidemiology (EAGLE) eczema consortium (N case = 18 900 and N control = 84 166, without the 23andMe study) were used to investigate the association with esophageal cancer in the UK Biobank study (N case = 740 and N control = 372 016) and BioBank Japan esophageal cancer sample (N case = 1300 and N control = 197 045). Results: When esophageal cancer extracted from East Asian ancestry was used as a outcome factor, AD data extracted from BioBank Japan (OR = 0.90, 95% CI: 0.83-0.98), FinnGen consortium (OR = 0.86, 95% CI: 0.77-0.96), and EAGLE consortium (OR = 0.92, 95% CI: 0.81-1.06) were negatively associated with esophageal cancer susceptibility. However, AD as a whole did not show an association with esophageal cancer from European ancestry. Conclusion: This study provides support for a causal relationship between AD and esophageal cancer in East Asian populations but not between AD and esophageal cancer from European ancestry. The specific associations between esophageal cancer and AD appear to exhibit significant disparities between the East Asian and European regions.

Will synchronous esophageal and lung resection increase the incidence of anastomotic leaks? A multicenter retrospective study.

BACKGROUND: Reports on combined resection for synchronous lung lesions and esophageal cancer (CRLE) cases are rare and mostly individual cases. Furthermore, the feasibility of CRLE has always been a controversial topic. In the current study, the authors retrospectively analyzed the feasibility of CRLE and established an individualized prediction model for esophageal anastomotic leaks after CRLE by performing a multicenter retrospective study. METHODS: Patients who underwent esophagectomy between January 2009 and June 2021 were extracted from a four-center prospectively maintained database, and those with CRLE at the same setting were matched in a 1:2 propensity score-matched (PSM) ratio to esophagectomy alone (EA) patients. A nomogram was then established based on the variables involved in multivariate logistic regression analysis. Internal validation of the nomogram was conducted utilizing Bootstrap resampling. Decision and clinical impact curve analysis were computed to assess the practical clinical utility of the nomogram. A prognosis analysis for CRLE and EA patients by Kaplan-Meier curves was conducted. RESULTS: Of the 7152 esophagectomies, 216 cases of CRLE were eligible, and 1:2 ratio propensity score-matched EA patients were matched. The incidence of anastomotic leaks following CRLE increased significantly ( P =0.035). The results of the multivariate analysis indicated the leaks varied according to the type of lung resection (anatomic>wedge resection, P =0.016) and site of resected lobe (upper>middle/low lobe; P =0.027), and a nomogram was established to predict the occurrence of leaks accurately (area under the curve=0.786). Although no statistically significant difference in overall survival (OS) was observed in the CRLE group ( P =0.070), a trend toward lower survival rates was noted. Further analysis revealed that combined upper lobe anatomic resection was significantly associated with reduced OS ( P =0.027). CONCLUSION: Our study confirms that CRLE is feasible but comes with a significantly increased risk of anastomotic leaks and a concerning trend of reduced survival, particularly when upper lobe anatomic resections are performed. These findings highlight the need for careful patient selection and surgical planning when considering CRLE.

Mechanisms of ligand recognition and activation of melanin-concentrating hormone receptors.

Melanin-concentrating hormone (MCH) is a cyclic neuropeptide that regulates food intake, energy balance, and other physiological functions by stimulating MCHR1 and MCHR2 receptors, both of which are class A G protein-coupled receptors. MCHR1 predominately couples to inhibitory G protein, Gi/o, and MCHR2 can only couple to Gq/11. Here we present cryo-electron microscopy structures of MCH-activated MCHR1 with Gi and MCH-activated MCHR2 with Gq at the global resolutions of 3.01 Å and 2.40 Å, respectively. These structures reveal that MCH adopts a consistent cysteine-mediated hairpin loop configuration when bound to both receptors. A central arginine from the LGRVY core motif between the two cysteines of MCH penetrates deeply into the transmembrane pocket, triggering receptor activation. Integrated with mutational and functional insights, our findings elucidate the molecular underpinnings of ligand recognition and MCH receptor activation and offer a structural foundation for targeted drug design.

Elevated intracellular pH of zygotes during mouse aging causes mitochondrial dysfunction associated with poor embryo development.

The mortality of preimplantation embryos is positively correlated with maternal age. However, the underlying mechanism for the poor quality of embryos remains unclear. Here, we found that aging caused elevated intracellular pH (pHi) in zygotes, which could trigger aberrant mitochondrial membrane potential, increased reactive oxygen species (ROS) levels, and poor embryo development. Moreover, single-cell transcriptome sequencing of mouse zygotes identified 120 genes that were significantly differentially expressed (DE) between young and older zygotes. These include genes such as Slc14a1, Fxyd5, CD74, and Bst, which are related to cell division, ion transporter, and cell differentiation. Further analysis indicated that these DE genes were enriched in apoptosis, the NF-kappa B signaling pathway, and the chemokine signaling pathway, which might be the key regulatory pathway affecting the quality of zygotes and subsequent embryo development. Taken together, our study helps elucidate the poor quality and development of older preimplantation embryos.

Lymphovascular and Perineural Invasion After Neoadjuvant Therapy in Esophageal Squamous Carcinoma.

BACKGROUND: Lymphovascular invasion and perineural invasion are unfavorable prognostic factors in patients with esophageal squamous cell carcinoma. However, the prevalence and prognostic importance of lymphovascular invasion and perineural invasion after neoadjuvant chemoradiotherapy in these patients remains unclear. METHODS: We retrospectively reviewed specimens of 321 patients with pathologically diagnosed esophageal squamous cell carcinoma who underwent neoadjuvant chemoradiotherapy in our institution from 2017 to 2020. Lymphovascular invasion and perineural invasion were assessed by hematoxylin and eosin staining. Survival was analyzed using the log-rank test and multivariable Cox regression analysis. RESULTS: Lymphovascular invasion and perineural invasion were present in 12.5% (n = 40) and 17.8% (n = 57) of resection specimens, respectively. Lymphovascular invasion and perineural invasion were significantly more common in patients with advanced cancer (both P < .05). In the univariate analyses, lymphovascular invasion and perineural invasion were associated with shorter overall survival and disease-free survival. Multivariable analysis revealed that lymphovascular invasion after neoadjuvant therapy was an independent adverse prognostic factor for overall survival and disease-free survival. Subgroup analyses showed that lymphovascular invasion could identify cases with worse overall survival or disease-free survival among node-negative patients, indicating the role of lymphovascular invasion in the precise staging of pN0 patients. CONCLUSIONS: Lymphovascular invasion and perineural invasion were significantly negatively correlated with overall survival and disease-free survival. Lymphovascular invasion was an independent prognostic predictor in esophageal squamous cell carcinoma patients after neoadjuvant chemoradiotherapy. Lymphovascular invasion and perineural invasion should be considered in the histopathology workup for esophageal squamous cell carcinoma patients after neoadjuvant chemoradiotherapy.

Deep Learning in Barrett's Esophagus Diagnosis: Current Status and Future Directions.

Barrett's esophagus (BE) represents a pre-malignant condition characterized by abnormal cellular proliferation in the distal esophagus. A timely and accurate diagnosis of BE is imperative to prevent its progression to esophageal adenocarcinoma, a malignancy associated with a significantly reduced survival rate. In this digital age, deep learning (DL) has emerged as a powerful tool for medical image analysis and diagnostic applications, showcasing vast potential across various medical disciplines. In this comprehensive review, we meticulously assess 33 primary studies employing varied DL techniques, predominantly featuring convolutional neural networks (CNNs), for the diagnosis and understanding of BE. Our primary focus revolves around evaluating the current applications of DL in BE diagnosis, encompassing tasks such as image segmentation and classification, as well as their potential impact and implications in real-world clinical settings. While the applications of DL in BE diagnosis exhibit promising results, they are not without challenges, such as dataset issues and the "black box" nature of models. We discuss these challenges in the concluding section. Essentially, while DL holds tremendous potential to revolutionize BE diagnosis, addressing these challenges is paramount to harnessing its full capacity and ensuring its widespread application in clinical practice.

A Novel Technique to Optimize Uniportal Thoracoscopic Right Middle Lobectomy.

The study aimed to describe a novel port design and simple surgical strategy for uniportal thoracoscopic right middle lobectomy. In this approach, a 3- to 4-cm incision was created at the sixth intercostal space posterior to the scapular line. The surgery was performed by serial division of the anterior oblique fissure, vein, bronchus, artery, and horizontal fissure. Based on our preliminary experience, this approach could provide an appropriate direction and angle for dissection and stapling, solving the challenge of conventional uniportal right middle lobectomy.

Short- and Long-Term Outcomes of Totally Versus Hybrid Minimally Invasive Ivor Lewis Oesophagectomy for Oesophageal Cancer: A Propensity Score-Matched Analysis.

Background: Few objective studies have compared totally minimally invasive Ivor Lewis oesophagectomy with hybrid procedure. Here we investigated whether the choice between totally and hybrid minimally invasive Ivor Lewis oesophagectomy influenced short-term outcomes and long-term patient survival. Methods: Patients who underwent totally or hybrid minimally invasive Ivor Lewis oesophagectomy between January 2014 and December 2017 were propensity score matched in a 1:1 ratio. The short- and long-term outcomes between the two groups were compared before and after matching. Results: Of 138 totally and 156 hybrid minimally invasive oesophagectomy patients were eligible, 104 patients from each group were propensity score matched. Totally minimally invasive oesophagectomy was associated significantly with less blood loss (median(IQR) 100(60-150) vs 120(120-200) ml respectively; P < 0.001), pneumonia (13.5 vs 25.0%; P = 0.035), pleural effusion (3.8 vs 13.5%; P = 0.014), and chest drainage (7.5(6-9) vs 8(7-9) days; P = 0.009) than hybrid procedure. There was no significant difference in 3-year overall survival rate and 3-year disease-free survival rate between the two group. Conclusions: Totally minimally invasive Ivor Lewis oesophagectomy may improve short-term outcomes and specifically reduce the incidence of pulmonary complications compared with hybrid procedure. The long-term overall survival and disease-free survival rates between the two groups were similar.

Is Tumor Regression Grade Sufficient to Predict Survival in Esophageal Cancer with Trimodal Therapy?

BACKGROUND: This study aimed to assess the predictive value of tumor regression grade (TRG) and nodal status on survival in esophageal carcinoma with neoadjuvant chemoradiotherapy (nCRT). METHODS: Tumor pathologic regression and nodal status were assessed. Differences in survival stratified by TRG or nodal status were analyzed using the Kaplan-Meier method and log-rank test. The prognostic value of TRG and nodal status were analyzed using univariate and multivariate Cox proportional hazards methods. RESULTS: From July 2016 to June 2019, 253 patients with esophageal cancer underwent nCRT followed by surgery. Significant differences were presented in survival according to nodal status but not TRG. Multivariate analysis showed that nodal status and not TRG was the only independent predicter for overall survival (HR: 3.550, 95% CI: 2.264-5.566, P < 0.001) and disease-free survival (HR: 2.801, 95% CI: 1.874-4.187, P < 0.001). The modified TRG system combining tumor regression with nodal status stratified patients survival with good discrimination. CONCLUSIONS: Lymph node status impacts more importantly than TRG on survival for patients with esophageal cancer undergoing nCRT plus esophagectomy. The modified TRG system may facilitate postoperative treatment decisions and survival surveillance.

Safety and Feasibility of Esophagectomy Following Neoadjuvant Immunotherapy Combined with Chemotherapy for Esophageal Squamous Cell Carcinoma.

Background: This study aimed to investigate the safety and feasibility of esophagectomy after neoadjuvant immunotherapy and chemotherapy for esophageal squamous cell carcinoma. Methods: We retrospectively identified patients who received neoadjuvant immunotherapy combined with chemotherapy (n = 38) in our center between 2020 and 2021. The primary end point was the risk of major complications (grade ≥3) according to the Clavien-Dindo classification. Secondary end points were surgical details, 30-day mortality, and 30-day readministration. Results: The most commonly used regimens of immunotherapy were camrelizumab (36.8%), pembrolizumab (31.5%), tislelizumab (15.8%), sintilimab (13.2%), and toripalimab (2.6%). The median interval to surgery was 63 days (range, 40-147). Esophagectomy was performed in 37 of 38 patients who received neoadjuvant immunotherapy and chemotherapy. All procedures were performed minimally invasively, except for 1 patient who was converted to thoracotomy. Of 37 surgical patients, R0 resection was achieved in 36 patients (97.3%). Pathologic complete response was observed in 9 patients (24.3%). Tumor regression grade I was identified in 17 patients (45.9%). Morbidity occurred in 12 of 37 patients (32.4%). The most common complication was pneumonia (16.2%). There were no deaths or readministration within 30 days. Conclusions: Esophagectomy following neoadjuvant immune checkpoint inhibitor plus chemotherapy for patients with resectable esophageal squamous cell carcinoma appears to be safe and feasible, with acceptable complication rates.