YAP regulates HER3 signaling-driven adaptive resistance to RET inhibitors in RET-aberrant cancer.

PURPOSE: Rearranged during transfection (RET) aberrations represent a targetable oncogene in several tumor types, with RET inhibitors displaying marked efficacy. However, some patients with RET-aberrant cancer are insensitive to RET tyrosine kinase inhibitors (TKIs). Recently, drug-tolerant mechanisms have attracted attention as targets for initial therapies to overcome drug resistance. The underlying mechanisms of drug-tolerant cell emergence treated with RET-TKIs derived from RET-aberrant cancer cells remain unknown. This study investigated the role of YAP-mediated HER3 signaling in the underlying mechanisms of adaptive resistance to RET-TKIs in RET-aberrant cancer cells. EXPERIMENTAL DESIGN: Four RET-aberrant cancer cell lines were used to assess sensitivity to the RET-TKIs selpercatinib and pralsetinib and to elucidate molecular mechanisms underlying adaptive resistance using RNA sequencing, phospho-RTK antibody arrays, chromatin immunoprecipitation assay, and luciferase reporter assays. Clinical specimens from patients with RET-fusion-positive lung cancer were analyzed for pre-treatment YAP expression and correlated with treatment outcomes. RESULTS: In high YAP-expressing RET-aberrant cancer cells, YAP-mediated HER3 signaling activation maintained cell survival and induced the emergence of cells tolerant to the RET-TKIs selpercatinib and pralsetinib. The pan-ErBB inhibitor afatinib and YAP/TEAD inhibitors verteporfin and K-975 sensitized YAP-expressing RET-aberrant cancer cells to the RET-TKIs selpercatinib and pralsetinib. Pre-treatment YAP expression in clinical specimens obtained from patients with RET-fusion-positive lung cancer was associated with poor RET-TKI treatment outcomes. CONCLUSION: The YAP-HER3 axis is crucial for the survival and adaptive resistance of high YAP-expressing RET-aberrant cancer cells treated with RET-TKIs. Combining YAP/HER3 inhibition with RET-TKIs represents a highly potent strategy for initial treatment.

Long-Term Outcomes of S-1 Combined With Low-Dose Docetaxel as Neoadjuvant Chemotherapy (N-1 Study, Phase II Trial) in Patients With Operable Breast Cancer.

BACKGROUND: We previously reported that S-1 and low-dose docetaxel (DOC) (N-1 study, phase II trial) could be a well-tolerated and effective neoadjuvant chemotherapies (NACs) for patients with operable breast cancer. Herein, we analyzed the long-term outcomes and developed clinicopathological and molecular predictors of pathological complete response (pCR). PATIENTS AND METHODS: Eighty-three patients received S-1 (40 mg/m2 orally on days 1-14) and DOC (40 mg/m2 intravenously on day 1) every 3 weeks for 4 to 8 cycles. Disease-free survival (DFS) and overall survival (OS) were analyzed for each population with a pCR status. To assess the relationship between pCR and clinicopathological factors such as tumor-infiltrating lymphocytes (TILs, 1+ <10%, 2+ 10%-50%, and 3+ >50%) and nuclear grade (NG), microarray was used to compare the microRNA profiles of the pCR and non-pCR groups using core needle biopsy specimens. RESULTS: With a median follow-up duration of 99.0 (range, 9.0-129.0) months, the 5-year DFS and OS rates were 80.7% and 90.9%, respectively. The 5-year OS rate of the pCR group was significantly better than that of the non-pCR group (100% vs. 86.2%, p = .0176). Specifically, in triple-negative patients, the difference was significant (100% vs. 60.0%, p = .0224). Multivariate analysis revealed that high TILs (≥2-3+) and NG 2-3 independently predicted pCR. Microarray data revealed that 3 miRNAs (miR-215-5p, miR-196a-5p, and miR-196b-5p) were significantly upregulated in the pCR group. CONCLUSION: Our NAC regimen achieved favorable long-term outcomes and significantly improved OS in the pCR group. High TILs, NG 2-3, and some miRNAs may be predictors of pCR.

Pulmonary adenocarcinoma in situ with morule - like components: A surgical case report.

Unusual lung adenocarcinoma with morule-like components is characterized by uniform, tightly packed spindle-shaped cells filling the lumens of neoplastic glandular structures. We present a case of a 78-year-old woman who presented with a part-solid ground-glass nodule in the upper lobe of the right lung. Following right upper lobectomy, histological examination revealed adenocarcinoma in-situ with multiple morule-like intra-alveolar proliferative nests of epithelial cells. Immunostaining was positive for thyroid-transcription factor 1 in the tumor cells and morule-like components. The tumor was also positive for an epidermal growth factor receptor mutation. This case provides valuable insights about lung adenocarcinoma in-situ with morule-like components.

AXL signal mediates adaptive resistance to KRAS G12C inhibitors in KRAS G12C-mutant tumor cells.

Recently, novel Kirsten rat sarcoma viral oncogene homolog (KRAS) inhibitors have been clinically developed to treat KRAS G12C-mutated non-small cell lung cancer (NSCLC) patients. However, achieving complete tumor remission is challenging. Therefore, the optimal combined therapeutic intervention with KRAS G12C inhibitors has a potentially crucial role in the clinical outcomes of patients. We investigated the underlying molecular mechanisms of adaptive resistance to KRAS G12C inhibitors in KRAS G12C-mutated NSCLC cells to devise a strategy preventing drug-tolerant cell emergence. We demonstrate that AXL signaling led to the adaptive resistance to KRAS G12C inhibitors in KRAS G12C-mutated NSCLC, activation of which is induced by GAS6 production via YAP. AXL inhibition reduced the viability of AXL-overexpressing KRAS G12C-mutated lung cancer cells by enhancing KRAS G12C inhibition-induced apoptosis. In xenograft models of AXL-overexpressing KRAS G12C-mutated lung cancer treated with KRAS G12C inhibitors, initial combination therapy with AXL inhibitor markedly delayed tumor regrowth compared with KRAS G12C inhibitor alone or with the combination after acquired resistance to KRAS G12C inhibitor. These results indicated pivotal roles for the YAP-GAS6-AXL axis and its inhibition in the intrinsic resistance to KRAS G12C inhibitor.

Conversion surgery after successful response to chemotherapy (S-1 + oxaliplatin + nivolumab) in a patient with stage IV gastric cancer with peritoneal metastasis (P1, CY1): a case report.

We here present a case report of a patient with Stage IV gastric cancer with peritoneal metastasis (P1, CY1) who underwent conversion surgery after a successful response to chemotherapy (S-1 + oxaliplatin + nivolumab). The patient was a woman in her 60 s. Her chief complaint was epigastric pain. Upper gastrointestinal endoscopy showed Type 4 advanced carcinoma on the lesser curvature of the gastric body. Biopsy showed Group 5 (poorly differentiated adenocarcinoma) and HER2 was negative. Staging laparoscopy revealed seeding in the round ligament of the liver (P1) and adenocarcinoma cells in ascites (CY1). Ten courses of chemotherapy (S-1 + oxaliplatin + nivolumab) were administered, after which contrast-enhanced computed tomography showed that the primary tumor had shrunk and seeding was no longer detectable. Upper gastrointestinal endoscopy revealed scar-like changes. A second staging laparoscopy revealed that ascites cytology was negative and a biopsy of the round ligament of the liver showed no malignant cells (P0, CY0). Conversion surgery comprising laparoscopic total gastrectomy with D2 lymph node dissection and resection of the round ligament of the liver was performed. The postoperative course was uneventful. Histopathological examination of the resected specimen revealed no tumor cells in the gastric mesentery or the round ligament of the liver. The pathological diagnosis was gastric cancer [M, U, L, Less, Ant, Post, type4, T3(SS), N0, M0 (H0, P0, CY0), ypStage IIA]. Adjuvant chemotherapy (S-1) was commenced. The patient is still alive 7 months later with no evidence of recurrence.

Insulin receptor expression to predict resistance to axitinib and elucidation of the underlying molecular mechanism in metastatic renal cell carcinoma.

BACKGROUND: The study aimed to examine the significance of insulin receptor (INSR) expression in predicting resistance to axitinib in clear cell renal cell carcinoma (ccRCC). METHODS: Clinicopathological data were collected from 36 consecutive patients with metastatic RCC who received axitinib. Thirty-three primary tumours were obtained for immunohistochemistry. Patient-derived xenograft (PDX) models were created by transplanting primary tumours into immunodeficient mice, establishing axitinib-resistant PDX models. RCC cell lines were co-cultured with human renal glomerular endothelial cells (HGECs) treated with siRNA of INSR (HGEC-siINSR). Gene expression alteration was analysed using microarray. RESULTS: The patients with low INSR expression who received axitinib had a poorer outcome. Multivariate analysis showed that INSR expression was the independent predictor of progression-free survival. INSR expression decreased in axitinib-resistant PDX tumours. RCC cell lines showed upregulated interferon responses and highly increased interferon-ß levels by co-culturing with HGEC-siINSR. HGECs showed decreased INSR and increased interferon-ß after axitinib administration. RCC cell lines co-cultured with HGEC-siINSR showed high programmed death-ligand 1 (PD-L1) expression, which increased after interferon-ß administration. CONCLUSIONS: Decreased INSR in RCC could be a biomarker to predict axitinib resistance. Regarding the resistant mechanism, vascular endothelial cells with decreased INSR in RCC may secrete interferon-ß and induce PD-L1.

Histological and immunohistochemical analysis of epithelial cells in epidermoid cysts in intrapancreatic accessory spleen.

BACKGROUND: Epidermoid cysts in intrapancreatic accessory spleen (ECIPAS) are a rare lesion. Its pathogenesis, including the origin of cystic epithelium, is not well established. We aimed to elucidate new aspects of the pathological features of ECIPAS to clarify its pathogenesis. METHODS: Six cases of ECIPAS were included in this study. As well as histopathological analysis, to elucidate the features and nature of cystic epithelial cells, immunohistochemical analysis including Pbx1 and Tlx1 and imaging mass spectrometry was performed. RESULTS: Histologically, the cysts were covered by either monolayered or multilayered epithelium. Immunohistochemistry revealed that the epithelial cells in multilayered epithelium exhibited different attributes between the basal and superficial layers. Few epithelial cells had abundant clear cytoplasm and were immunohistochemically positive for adipophilin, suggesting lipid-excreting function. The intracystic fluid contained cholesterol clefts and foamy macrophages, and imaging mass spectrometry revealed the accumulation of lipids. Immunohistochemical analysis indicated that the epithelial cells were positive for Pbx1 in some cases. CONCLUSION: Novel histological features of epithelial cells of ECIPAS were indicated. Although more cases need to be evaluated, we propose that the cause of ECIPAS may be different from that of pancreatic ductal origin. J. Med. Invest. 70 : 251-259, February, 2023.

Squamous cell carcinoma invading peripheral cerebral blood vessels and causing repeated cerebral hemorrhage : A case report.

Squamous cell carcinoma (SCC) is known to have less brain metastasis, but the reasons are not well established. Herein, we report the case of an 82-year-old man with recurrent cerebral hemorrhage of unknown cause ; upon brain biopsy, SCC was diagnosed infiltrating peripheral blood vessels of the brain and that it was state of micro-metastasis. It is possible that the blood-brain barrier blocked the infiltration of SCC into the brain parenchyma, and it did not form a mass in the brain parenchyma. In addition, because it did not form a mass, it could not be diagnosed as a metastatic brain tumor by contrast-enhanced magnetic resonance imaging or contrast-enhanced computed tomography. Among cases of recurrent cerebral hemorrhage of unknown cause in a short period, there may be cases of vascular infiltration without crossing the blood-brain barrier. Thus, if similar cases of recurrent cerebral hemorrhage of unknown cause is observed, it is necessary to distinguish metastatic brain tumors even if there is no evidence of suspected tumor on contrast-enhanced magnetic resonance imaging scan. J. Med. Invest. 70 : 276-280, February, 2023.

Recurrent multiple liver metastases of clear cell renal cell carcinoma with a significant response to sunitinib after nivolumab treatment.

Introduction: A case of multiple liver metastases of clear cell RCC with a significant response to sunitinib as the fifth line after nivolumab is reported. Case presentation: The patient was a 65-year-old man who underwent open nephrectomy for RCC. After the nephrectomy, he had recurrences several times, and metastasectomy had been performed for each recurrence. At 13 years after the nephrectomy, multiple liver, and lung metastases appeared. The treatment was switched to axitinib, followed by cabozantinib, then nivolumab. The best response was PR, SD, and PD for these three drugs, and treatment duration was 14, 3, and 3 months, respectively. As the fifth line, sunitinib was administered, with significant shrinkage of the multiple liver metastases, and PR has been maintained for 34 months. Conclusion: Sunitinib after an IO-drug showed a significant effect in spite of only slight efficacy with other VEGFR-TKIs, which may have occurred through the alteration of the immunological microenvironment.

Imaging features of a myoepithelial carcinoma of the nasal cavity: A case report and literature review.

Myoepithelial carcinoma of the nasal cavity is extremely rare. We report the case of a 66-year-old man with myoepithelial carcinoma of the nasal cavity. Computed tomography (CT) and magnetic resonance imaging revealed a lobulated soft tissue mass with central necrosis and hemorrhage, as well as an invasion of the skull base and left orbit. The patient presented with continuous nasal congestion and heavy head and had no elevated level of squamous cell carcinoma-related antigen. CT, magnetic resonance imaging, or 18F-fluorodeoxyglucose (FDG) positron emission tomography/CT revealed no evidence of a metastatic lesion. 18F-FDG accumulation in the tumor was inhomogeneous and moderate. Histopathological examination of the resected specimen confirmed a well-circumscribed solid tumor with septa, a small area of hemorrhage, and necrosis. The subsequent diagnosis was a myoepithelial carcinoma of the left nasal cavity. This case shows that nasal myoepithelial carcinoma might appear as a well-defined lobulated mass with hemorrhagic necrosis and intense contrast enhancement in the solid component. We conjecture that hemorrhagic necrosis and intense enhancement values may be potential markers of nasal myoepithelial carcinoma.

Pleomorphic type undifferentiated gastric sarcoma, report of a case.

Reports on pleomorphic type of undifferentiated sarcoma (PUS) originating from the gastrointestinal tract, especially the stomach, are extremely rare. We herein report a case of pleomorphic type undifferentiated gastric sarcoma. The patient was a 67-year-old woman. The chief complaint was upper abdominal pain. Upper gastrointestinal endoscopy, ultrasonography, and contrast-enhanced computed tomography showed two submucosal tumors at the greater curvature of the fundus and the lesser curvature of the gastric angle. Endoscopic ultrasound-guided fine-needle aspiration revealed a c-kit-negative spindle cell tumor at the greater curvature of the fundus. Total gastrectomy, splenectomy, and partial resection of the diaphragm and liver were performed. One lesion had invaded the lateral segment of the liver, left diaphragm and spleen. The postoperative course was uneventful. Histopathological and immunohistochemical examinations of the resected specimen revealed PUS. Peritoneal dissemination was detected at 8 months after surgery. However, no effective therapeutic agents were adopted for chemotherapy. The patient had poor performance status due to disease progression and underwent best supportive care. The patient died 10 months after surgery. This case highlights the imaging, histological diagnosis, and treatment strategy for PUS originating from the stomach. Surgeons should be aware of PUS as a differential diagnosis in cases with submucosal tumor of the stomach.

High levels of AXL expression in untreated EGFR-mutated non-small cell lung cancer negatively impacts the use of osimertinib.

For non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations, the initial therapeutic interventions will have crucial impacts on their clinical outcomes. Drug tolerant factors reportedly have an impact on EGFR-tyrosine kinase inhibitor sensitivity. This prospective study investigated the impacts of drug tolerant-related protein expression in tumors based on the efficacy of osimertinib in the first-setting of EGFR-mutated advanced NSCLC patients. A total of 92 patients with EGFR-mutated advanced or postoperative recurrent NSCLC were analyzed and treated with osimertinib at 14 institutions in Japan. AXL, p53, and programmed death-ligand 1 (PD-L1) expression in patient tumors was determined using immunohistochemistry. The AXL signaling pathway was investigated using a cell line-based assay and AXL-related gene expression in The Cancer Genome Atlas (TCGA) database. High levels of AXL and positive-p53 expression were detected in 26.1% and 53.3% of the pretreatment EGFR-mutated NSCLC tumors, respectively. High AXL expression levels were significantly associated with a shorter progression-free survival compared with low AXL expression levels, irrespective of the EGFR activating mutation status (p = 0.026). Cell line-based assays indicated that the overexpression of AXL protein accelerated PD-L1 expression, which induced insensitivity to osimertinib. In the TCGA database, AXL RNA levels were positively correlated with PD-L1 expression in the lung adenocarcinoma cohort. The results show that high AXL expression levels in tumors impact clinical predictions when using osimertinib to treat EGFR-mutated NSCLC patients. Trial Registration: UMIN000043942.

[Primary cutaneous anaplastic large cell lymphoma with systemic progression responding to low-dose methotrexate therapy].

The standard therapies for primary cutaneous anaplastic large cell lymphoma (pcALCL) in an advanced stage remain undefined. A 71-year-old man presented with multiple erythema and nodules. He was diagnosed with lymphomatoid papulosis (LyP) through a skin biopsy from the left postauricular area. All skin lesions achieved complete response by electron beam irradiation. However, nodular lesions appeared in both inner canthi 5 months later. Histopathological evaluation of the lesional biopsy revealed dominant infiltration of CD30-positive large cells. Positron emission tomography/computed tomography revealed fluorodeoxyglucose-positive cervical and inguinal lymph node swelling and right tonsillitis, followed by the diagnosis of pcALCL and TNM classification T3bN3M0. Since the patient had severe chronic obstructive pulmonary disease and recurrent pneumonia, he received low-dose methotrexate (MTX) (15 mg/week) therapy. Low-dose MTX effectively debulked the lymphadenopathies over time without particular adverse effects. Although the standard therapies for pcALCL are not established, low-dose MTX was effective and considered safe for patients with frailty and compromised respiratory function. Further study is warranted on the pathophysiology of pcALCL after the development of LyP and mechanisms of action of low-dose MTX against LyP and pcALCL.

Axillary lymphangioma that developed following COVID-19 vaccination: a case report.

BACKGROUND: Extensive vaccination programs are being implemented worldwide for coronavirus disease 2019 (COVID-19). With the spread of vaccination, swelling of the lymph nodes after vaccination is frequently seen. We encountered a patient who developed left axillary lymphadenoma following vaccine administration. CASE PRESENTATION: The patient was a Japanese woman in her 80 s who had previously undergone surgery for right breast cancer. She received two injections of the Pfizer-BioNTech COVID-19 vaccine in her left arm. Approximately 3 months later, she complained of left axillary swelling, and imaging resulted in a diagnosis of left axillary lymphangioma. In accordance with the patient's wishes, we performed axillary mass resection. The pathological diagnosis was lymphangioma. CONCLUSION: Our examination findings indicated that congestion of the axillary lymph vessels might have been caused by upper-arm injections of the COVID-19 vaccine.

[A Case of Pappilary Renal Cell Caircinoma which Responded Well to the Combination Therapy of Ipilimumab and Nivolumab --A CASE REPORT-].

We report a case of papillary renal cell carcinoma that responded well to the combination of ipilimumab and nivolumab. The patient was a 68-year-old male who was being followed up for a small left renal mass without treatment. Two years later, computed tomography (CT) showed enlarged cervical and para-aortic lymph nodes, and lymph node biopsy suggested metastases of the cancer. After resection of the renal tumor, we performed pararenal aortic lymph node biopsy, and we diagnosed the case as papillary renal cell carcinoma type 1 with lymph node metastasis. The combination of ipilimumab and nivolumab each metastatic site showed regression on CT. Since immune-related adverse events occurred during the therapy nivolumab was discontinued, but partial response of the metastases was maintained.

HER3 activation contributes toward the emergence of ALK inhibitor-tolerant cells in ALK-rearranged lung cancer with mesenchymal features.

Anaplastic lymphoma kinase-tyrosine kinase inhibitors (ALK-TKIs) have shown dramatic efficacy in patients with ALK-rearranged lung cancer; however, complete response in these patients is rare. Here, we investigated the molecular mechanisms underlying the emergence and maintenance of drug-tolerant cells in ALK-rearranged lung cancer. Cell based-assays demonstrated that HER3 activation and mesenchymal-to-epithelial transition, mediated through ZEB1 proteins, help maintain cell survival and induce the emergence of ALK-TKI-tolerant cells. Compared with ALK-TKIs alone, cotreatment with pan-HER inhibitor afatinib and ALK-TKIs prevented tumor regrowth, leading to the eradication of tumors in ALK-rearranged tumors with mesenchymal features. Moreover, pre-treatment vimentin expression in clinical specimens obtained from patients with ALK-rearranged lung cancer was associated with poor ALK-TKI treatment outcomes. These results demonstrated that HER3 activation plays a pivotal role in the emergence of ALK-TKI-tolerant cells. Furthermore, the inhibition of HER3 signals combined with ALK-TKIs dramatically improves treatment outcomes for ALK-rearranged lung cancer with mesenchymal features.

A case of pulmonary pleomorphic carcinoma with preexisting interstitial pneumonia successfully treated with pembrolizumab.

Pulmonary pleomorphic carcinoma is often refractory to chemotherapy and follows an aggressive clinical course. Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of advanced lung cancer, and a few cases with pleomorphic carcinoma have been reported to show tumor shrinkage after therapy with ICIs. When treating patients with ICIs, patient selection is essential, and monitoring and management of immune-related adverse events, including pneumonitis, are needed. We herein report a case of pulmonary pleomorphic carcinoma with preexisting interstitial pneumonia treated with pembrolizumab, antiprogrammed cell death 1 antibody. Our report highlights important considerations necessary when treating advanced pleomorphic carcinoma patients complicated with interstitial pneumonia. We also review the literature regarding the use of ICIs in such patients.

ypN0 in Patients With Definitive cN-positive Status After Preoperative Treatment Is a Prognostic Factor in Esophageal Cancer.

BACKGROUND: Histopathological tumor regression grade is applied not to lymph nodes but primary tumors modified by preoperative treatments. This study focused on patients whose pathological examination at the time of surgery showed no residual tumor after chemo(radio)therapy in the primary lesion (ypT0) or lymph nodes (ypN0). PATIENTS AND METHODS: A total of 87 patients with clinical stage II/III thoracic esophageal cancer underwent esophagectomy following preoperative treatments to evaluate significances between pathological response and clinical outcomes; 51 patients with clinically definitive lymph node metastasis (cN+) were analyzed as a subgroup. RESULTS: ypT0 rates were 20.7% and 23.5%, and ypN0 rates were 47.1% and 27.5% in the whole cohort and in the cN+ subgroup, respectively. Disease-free survival, from surgery to relapse or death, was significantly influenced by ypN status (p=0.035) but not by ypT status in the 51 patients with definitive cN+ disease. Preoperative chemoradiation was an independent favorable factor for achievement of ypN0 in the 51 patients (odds ratio=0.09; p=0.007). CONCLUSION: ypN status was a predictive factor for DFS in patients treated with docetaxel plus low-dose 5-fluorouracil and cisplatin combined chemotherapy, superior to ypT status, especially in patients with definitive cN+ disease.

A RAS inhibitor reduces allergic airway remodeling via regulating IL-33-derived type 2 innate lymphoid cells.

Purpose: IL-33 is known to induce corticosteroid-resistant eosinophilic inflammation and airway remodeling by activating type 2 innate lymphoid cells (ILC2s). Although the RAS signal pathway plays an important role in IL-33-induced ILC2s activation and airway remodeling, it is not known if RAS inhibitors are effective against refractory asthma. We examined the effects of the RAS inhibitor XRP44X in refractory asthma. Methods: RAS activity were examined by BAL fluid and T-cells isolated from spleen cells in Dermatophagoides pteronyssinus (Dp)-sensitized/challenged acute allergic airway inflammation model. A chronic allergic airway inflammation mouse model was generated by challenged with Dp. XRP44X and/or fluticasone were administrated nasally to different experimental groups. The effects of nasal simultaneous administration of XRP44X or fluticasone were assessed in mice administrated with IL-33 or Dp. Results: RAS activity in CD4+ T cells stimulated by Dp were suppressed by XRP44X. Although fluticasone and XRP44X only improved allergic airway inflammation in mice, XRP44X in combination with fluticasone produced further improvement in not only eosinophilic inflammation but also bronchial subepithelial thickness. XRP44X suppressed IL-5 and IL-13 production from ILC2s, although this effect was not suppressed by fluticasone. IL-33-induced airway inflammation resistant to fluticasone was ameliorated by XRP44X via regulating the accumulation of lung ILC2s. Conclusion: The RAS signal pathway plays a crucial role in allergen-induced airway remodeling associated with ILC2s. XRP44X may have therapeutic potential for refractory asthma.

Necroptosis protects against exacerbation of acute pancreatitis.

The sensing of various extrinsic stimuli triggers the receptor-interacting protein kinase-3 (RIPK3)-mediated signaling pathway, which leads to mixed-lineage kinase-like (MLKL) phosphorylation followed by necroptosis. Although necroptosis is a form of cell death and is involved in inflammatory conditions, the roles of necroptosis in acute pancreatitis (AP) remain unclear. In the current study, we administered caerulein to Ripk3- or Mlkl-deficient mice (Ripk3-/- or Mlkl-/- mice, respectively) and assessed the roles of necroptosis in AP. We found that Ripk3-/- mice had significantly more severe pancreatic edema and inflammation associated with macrophage and neutrophil infiltration than control mice. Consistently, Mlkl-/- mice were more susceptible to caerulein-induced AP, which occurred in a time- and dose-dependent manner, than control mice. Mlkl-/- mice exhibit weight loss, edematous pancreatitis, necrotizing pancreatitis, and acinar cell dedifferentiation in response to tissue damage. Genetic deletion of Mlkl resulted in downregulation of the antiapoptotic genes Bclxl and Cflar in association with increases in the numbers of apoptotic cells, as detected by TUNEL assay. These findings suggest that RIPK3 and MLKL-mediated necroptosis exerts protective effects in AP and caution against the use of necroptosis inhibitors for AP treatment.