Development and Validation of a Tool for Assessing Adherence to Gluten-Free Diet in Patients With Celiac Disease.

INTRODUCTION: Life-long adherence to gluten-free diet (GFD) and its assessment is essential for patients with celiac disease (CeD). We have developed and validated a tool for assessing adherence to GFD which can be used by both physicians and dietitians. METHODS: Phase 1: Development, content validation, and assessment of reliability of tool. Phase 2: Validation of tool against standard dietary evaluation (SDE) (gold standard), immunoglobulin A - anti-tissue transglutaminase antibodies (IgA anti-tTG Ab), and gluten immunogenic peptides in urine. Overall, 380 biopsy-confirmed patients with CeD (derivation cohort: n = 100 [phase 1], n = 210 [phase 2] and independent validation cohort, n = 70) were recruited. RESULTS: Of an initial 90-point questionnaire, 84 items (Celiac Disease: Compliance Assessment Test [CD-CAT.v1]) were retained after content validation and pilot testing. In phase 1, upon administering CD-CAT.v1 on 100 patients, a comprehensive 35-item tool (CD-CAT.v2; α = 0.86) was obtained after removing items with low test-retest reliability and item-rest correlation values. In phase 2, upon administering CD-CAT.v2 on 210 patients, 22 items were removed having low correlation values (R < 0.4) with SDE. Finally, a 13-item tool (CD-CAT.v3; α = 0.84) was obtained with high criterion validity with SDE ( r = 0.806, P < 0.001), moderate convergent validity with celiac disease adherence test ( r = 0.602, P = 0.007), and moderate to weak correlation with urine gluten immunogenic peptides ( r = 0.46, P = 0.001) and IgA anti-tTG Ab ( r = 0.39, P = 0.008), respectively. The final 13-item tool also strongly correlated with SDE ( r = 0.78, P < 0.001) in an independent validation cohort of 70 patients with CeD. Principal component analysis identified 3 relevant subscales with a cumulative variance of 62%. The sensitivity and specificity of CD-CAT.v3 were 80% and 91%, respectively, with an area under curve of 0.905 with SDE. The obtained cutoff score of <19 from the receiver operating characteristic curve was further categorized as 13 = excellent, 14-18 = very good, 19-28 = average, and >28 = poor adherence to GFD. DISCUSSION: CD-CAT is a new and rapid tool for monitoring dietary adherence to GFD with high sensitivity and specificity, which can be administered by both physicians and dietitians.

Label-Free Tracking of Hepatitis B Virus Core Protein Capsid Assembly in Real-Time Using Protein Charge Transfer Spectra.

Hepatitis B virions are double-shelled particles, with a diameter of 40-42 nm, consisting of a nucleocapsid called the HBV core protein (HBV Cp). It is an ordered assembly of 90-120 homodimers arranged in an icosahedral symmetry. Both the full-length HBV Cp and the first-149 residue domain, HBV Cp149, can spontaneously assemble in vitro into capsids with 120 Cp dimers (T = 4) or 90 Cp dimers (T = 3), triggered by high ionic strength of 0.25-0.5 M NaCl. The assembly disassembly of HBV Cp149 capsids are generally studied by light scattering, size-exclusion chromatography, atomic force microscopy, transmission electron microscopy, and other high-end expensive techniques. Here, we report a simple, yet robust, label-free technique exploiting protein charge transfer spectra (ProCharTS) to monitor the capsid assembly in real-time. ProCharTS absorption in the near UV-visible region (250-800 nm) arises when photoinduced electron transfer occurs from HOMO of COO- in glutamate (donor) to LUMO of NH3+ in lysine or polypeptide backbone (acceptor) of the protein. Alternatively, it can also occur from polypeptide backbone (donor) to acceptor in arginine, histidine, or lysine cation. ProCharTS is observed profusely among proximal charge clusters in folded proteins. Here, we show that, ProCharTS absorption among growing HBV capsids is amplified when HBV Cp homodimers assemble, generating new contacts among charged residues in the dimer-dimer interface. We notice a time-dependent sigmoidal increase in ProCharTS absorbance and luminescence during capsid formation in comparison to pure dimers. Additionally, a combined approach of anisotropy-based fluorescence assay is reported, where an increased fluorescence anisotropy was observed in capsids as compared to native and unfolded dimers. We conclude that ProCharTS can serve as a sensitive label-free tool for rapid tracking of capsid assembly in real-time and characterize the assembled capsids from dimers.

Acquired resistance to immunotherapy and chemoradiation in MYC amplified head and neck cancer.

The proto-oncogene MYC encodes a nuclear transcription factor that has an important role in a variety of cellular processes, such as cell cycle progression, proliferation, metabolism, adhesion, apoptosis, and therapeutic resistance. MYC amplification is consistently observed in aggressive forms of several solid malignancies and correlates with poor prognosis and distant metastases. While the tumorigenic effects of MYC in patients with head and neck squamous cell carcinoma (HNSCC) are well known, the molecular mechanisms by which the amplification of this gene may confer treatment resistance, especially to immune checkpoint inhibitors, remains under-investigated. Here we present a unique case of a patient with recurrent/metastatic (R/M) HNSCC who, despite initial response to nivolumab-based treatment, developed rapidly progressive metastatic disease after the acquisition of MYC amplification. We conducted comparative transcriptomic analysis of this patient's tumor at baseline and upon progression to interrogate potential molecular processes through which MYC may confer resistance to immunotherapy and/or chemoradiation and used TCGA-HNSC dataset and an institutional cohort to further explore clinicopathologic features and key molecular networks associated with MYC amplification in HNSCC. This study highlights MYC amplification as a potential mechanism of immune checkpoint inhibitor resistance and suggest its use as a predictive biomarker and potential therapeutic target in R/M HNSCC.

Reproductive functions and pregnancy outcome in female patients with celiac disease.

BACKGROUND AND AIM: Abnormalities in the reproductive functions are often ignored while evaluating a patient with celiac disease (CeD). We evaluated the entire reproductive functions in female patients with CeD. METHODS: In a case control study between 2020 and 2021 using detailed questionnaire, we evaluated reproductive functions (age at menarche, menstrual pattern, fertility, pregnancy outcome and menopause) in biopsy-proven female patients with CeD of age >10 years. The questionnaire was administered either in person or telephonically. Age-matched healthy female controls (twice the number) were also recruited. RESULTS: Of 1086 CeD patients, 470 were females and 288 were included. As compared with controls (n = 586), females with CeD had higher age at menarche (14.6 ± 2.0 vs 13.6 ± 1.5 years; P = 0.001), delayed menarche (30.8% vs 11.4%; P = 0.001), abnormal menstrual pattern (39.7% vs 25.8%; P < 0.001), involuntary delay in conception at > 1 year (33.8% vs 11.8%; P = 0.01), current infertility rate (10.5% vs 5.2%;P = 0.028), and poorer overall pregnancy outcomes (abortion [23.5% vs 12.8%; P = 0.001], pre-term birth [16.3% vs 3.7%; P = 0.001]). CONCLUSIONS: Either one or more aspect of reproductive functions and pregnancy outcome is affected adversely in three-fourth female patients with CeD.

Correlation between intestinal stem cell niche changes and small bowel crypt failure in patients with treatment-naïve celiac disease.

OBJECTIVES: We hypothesized that crypt failure in the small bowel results in villous flattening in patients with celiac disease (CeD). We investigated whether alterations in the stem cell niche (ISC) are responsible for this phenomenon. MATERIALS AND METHODS: We included 92 duodenal (D2/3) biopsies from treatment-naive patients of CeD and 37 controls. All underwent screening for serum anti-tissue transglutaminase and endoscopic upper small bowel biopsy. Immunohistochemical markers were used to investigate ISC niche alterations, including LGR5 for crypt basal cells (CBC), Bmi1 for position 4+ cells, ß-Defensin for Paneth cells, R-spondin1 as WNT activator, transcription factor-4 as WNT transcription factor, BMP receptor1A as WNT inhibitor, fibronectin-1 as periepithelial stromal cell marker, H2AX as apoptosis marker, and Ki67 as proliferation marker. We also analyzed IgA anti-tTG2 antibody deposits by using dual-color immunofluorescence staining. RESULTS: We found that in biopsies from patients with treatment-naive CeD with modified Marsh grade 3a-3c changes, the epithelial H2AX apoptotic index was upregulated than in controls. LGR5+ crypt basal cells were upregulated in all modified Marsh grades compared to controls. However, the Ki67 proliferation index, expressions of WNT-activator RSPO1, and position-4 cell marker Bmi1 did not significantly alter in patients' biopsies as compared to controls ( P = 0.001). We also observed depletion of pericrypt stromal fibronectin-1 in patients with CeD compared to controls. In addition, we identified IgA anti-TG2 antibody deposits in pericrypt stroma. CONCLUSIONS: Our data suggests that ISC niche failure is a plausible hypothesis for villous flattening in patients with CeD, resulting from pericrypt IgA anti-TG2 antibody complex-mediated stromal depletion.

Significance of histopathological features in the diagnosis of Budd-Chiari syndrome on liver biopsies.

Background: Budd-Chiari syndrome (BCS) requires a constellation of clinical, imaging, and histological findings for diagnosis. Liver biopsy serves as a tool for confirming the diagnosis, even though the histological characteristics are not pathognomonic. Aims: To determine which constellation of morphologic findings could aid in establishing a diagnosis of BCS in clinically suspected cases. Materials and Methods: A 5-year retrospective observational study was conducted. The clinical, laboratory, and histological findings of liver biopsies in patients with a clinical diagnosis of BCS were studied. Cases were segregated into two groups on the basis of the number of histological features present. A scoring system was then devised to assess the efficacy of the histological findings in diagnosing BCS. Statistical Analysis Used: The continuous variables were compared using the Mann-Whitney U-test, and categorical variables were compared using the Fisher-exact test. Results: The common histopathological findings were the presence of red blood cells in the space of disse (100%), peri-portal fibrosis (97.1%), sinusoidal dilation (97.1%), portal inflammation (67.6%), centrilobular necrosis (61.8%) and pericellular/sinusoidal fibrosis (61.8%). Comparison between the two groups showed that centrilobular necrosis, lobular inflammation, portal inflammation, central vein fibrosis, and pericellular/sinusoidal fibrosis were significant parameters. No correlation was found between the clinical and laboratory parameters and the two groups. Conclusions: The liver biopsy features in BCS are often nonspecific, and no single feature in isolation is characteristic. A constellation of features (centrilobular necrosis, lobular inflammation, portal inflammation, central vein fibrosis, and pericellular/sinusoidal fibrosis), when present together, indicate the possibility of BCS.

Pediatric Thyroid Lesions: Synergistic Role of Clinical and Cytological Features in Diagnosis.

INTRODUCTION: Thyroid lesions in childhood and adolescence are uncommon, and the risk of malignancy widely varies. They require careful evaluation and more aggressive diagnostic approach. The present study aimed to evaluate the frequency of various pediatric thyroid lesions in pediatric cases with thyroid nodules and ascertain the utility of clinical, laboratory, ultrasonography, and fine-needle aspiration cytology (FNAC) findings to discriminate between benign and malignant lesions. METHODS: A retrospective study where 95 consecutive cases of pediatric patients with thyroid nodules received over six years (January 2016-December 2021) were retrieved from the hospital information system. The differences in clinical, laboratory, ultrasonography, and cytological findings between benign and malignant lesions were analysed. Statistical analysis was performed using SPSS software (version 21.0). RESULTS: The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) was used to categorise the cases into: unsatisfactory (n=3), benign (n=66), intermediate (n=8) and suspicious/malignant (n=18). The specificity of cytopathology in diagnosing benign lesions (TBSRTC-II) was 90%, whereas sensitivity in diagnosing malignant lesions (TBSRTC-VI) was 100%. Colloid nodule (n=57) and papillary thyroid carcinoma (n=15) were the most common benign and malignant lesions encountered respectively. Malignant lesions more frequently showed the presence of palpable lymph nodes (p-value <0.001), microcalcifications (p-value 0.011) and intranodular vascularization (p-value <0.001). CONCLUSION: The diagnosis of pediatric thyroid lesions should be based on a multistep evaluation that includes clinical, laboratory, and radiographic modalities. Thyroid function tests and ultrasonography can help identify clinically unapparent thyroid nodules and provide detailed nodule characterization for suspected malignant lesions. FNAC is a simple, less-invasive, and cost-effective technique that can differentiate between benign and malignant thyroid lesions.

Falsely elevated anti-tissue transglutaminase antibodies in patients with immunoproliferative small intestinal diseases: A case series.

Immunoproliferative small intestinal disease (IPSID) is an uncommon disease of the small intestine. There is a similarity in the clinical presentations of enteropathic diseases, including celiac disease, tropical sprue, IPSID, and Whipple's disease. A differentiation between them is based on the use of a highly specific serological test for celiac disease and specific histological characteristics. We found that IgA-anti-tissue transglutaminase antibody (IgA-tTG Ab) is falsely elevated in a subset of patients with IPSID. The levels of IgA-tTG Ab fall with the treatment of IPSID. The healthcare professional should be aware of the conditions that lead to a false-positive anti-tTG Ab. Intestinal mucosal biopsies even in the presence of anti-tTG Ab should be done in endemic regions as they provide an opportunity for making a diagnosis of alternative and uncommon diseases before the diagnosis of celiac disease.

Patterns of practice in the diagnosis, dietary counselling and follow-up of patients with celiac disease- A patient-based survey.

BACKGROUND: The pattern of practice regarding the diagnosis, dietary counselling and follow-up of patients with celiac disease (CeD) varies between practice to practice. METHODS: A web-based questionnaire based on review of literature, group discussions and expert group meetings was developed to understand the practice of CeD in India. The questionnaire was administered through social media (WhatsApp) to 18 Indian celiac support groups comprising 2980 patients with CeD. RESULTS: Overall, 970 (32.5%) patients responded to the questionnaire (median age: 21 years; females 63.9%). While 679 (71.1%) patients were diagnosed based on a combination of serology and biopsy, 214 (22.4%) were diagnosed based on serology alone. After diagnosis, 875 (91%) patients were counselled initially by physician and only 585 (61%) were referred to a dietician for dietary counselling. In a majority of cases, the time spent by doctors and dietitians during first counselling was between 10 and 20 minutes only. After first counselling, 191 (20%) and 355 (37.3%) patients did not re-visit the physician and the dietitian, respectively. Among those who followed up, structured follow-up was conducted in only 515 (53.8%) patients. Overall, 232 (24.3%) patients were self-monitoring their serological parameters, while 495 (51.8%) patients did not receive a formal assessment of dietary adherence during follow-up. CONCLUSION: The practice of diagnosis, dietary counselling and follow-up of patients with CeD in India is not as per standard guidelines. Most of the patients are not referred to a dietitian. There is a need for reinforcement of guidelines for proper care and management of patients with CeD.

Indole-3-carbinol induces apoptosis in AGS cancer cells via mitochondrial pathway.

Indole-3-carbinol is produced from the cruciferous vegetables and broadly investigated for their various biological effects in in-vitro and in-vivo aspects. However, the anticancer activity of I3C and its molecular mechanisms have not been investigated in human adeno gastro carcinoma (AGS) cells. In our study of AGS cells, nuclear condensation was observed by 4',6-diamidino-2-phenylindole (DAPI) staining, cell death was confirmed by a cell viability assay, and fragmented DNA was observed at the IC50 dose by a DNA fragmentation assay. Apoptosis was evaluated by the qPCR technique. Treatment of the AGS cells with I3C at different concentrations has drastically decreased cell proliferation and differentiation. By releasing cytochrome-c from mitochondria in the intrinsic pathway, I3C prevents the multiplication of AGS cells and initiates apoptosis. The WST-1 assay result showed that I3C treatment against AGS cells had considerably reduced the viability of the cells. Furthermore, RT-qPCR showed the fold change among the expressed proteins compared with reference gene ß-actin. Molecular docking revealed that I3C showed a strong binding affinity for the apoptotic protein 3DCY. The results show the caspase group of proteins contribute to the core of apoptotic machinery. I3C and its metabolites target a variety of components of cell-cycle control via distinct signaling pathways in light of the rapid development of tumors and oncogenesis. The translational significance of I3C and its metabolites in cancer is highlighted by their wide range of antitumor activity and low toxicity. Furthermore, the novel prodrug I3C, which has overlapping underlying mechanisms, could encourage new strategies to decrease oncogenesis.

Gastrointestinal tract involvement in patients with potential celiac disease beyond the small intestine: An early proof with IgA anti-tissue transglutaminase-2 antibody deposits.

Background: IgA anti-tissue transglutaminase-2 antibody (anti-TG2Ab) deposits in intestinal and extraintestinal organs have been used to link the respective pathological changes in these organs with celiac disease (CeD). Aims: To know if parts of intestine other than the duodenum, such as esophagus, stomach, and colon, have any pathology related to potential CeD or have mucosal IgA anti-TG2 Ab deposits. Settings and Design: A prospective case-control study conducted from April 2018 to December 2019. Materials and Methods: Nine patients with potential CeD and 27 age- and gender-matched patients with irritable bowel syndrome were recruited as cases and controls, respectively. Mucosal biopsies were collected from esophagus, stomach, duodenum, and rectosigmoid regions, histological changes were evaluated, and IgA anti-TG2 Ab deposits were analyzed in these regions by two-color immunohistochemical staining. Statistics: Data were analyzed using statistical software Stata 14.0. Results: No distinct difference in mucosal lymphocytosis were identified between biopsies of patients with potential CeD and controls at the following sites: esophagus (11.1% vs 0%, P = 0.079), stomach (14.3% vs 7.7%, P = 0.590), and rectum (20% vs 0%, P = 0.067). Co-localized IgA anti-TG2Ab deposits were observed more in potential CeD than in controls at esophagus 22.2% (2/9) vs 0%, P = 0.012; stomach 66.7% (6/9) vs 11.5% (3/26), P < 0.001; and duodenum 66.7% (6/9) vs 0%, P < 0.001 but not at rectum 0% (0/4) vs 0% (0/25). Conclusion: Although histological changes are not distinct, a subset of subjects with potential CeD has pan-intestinal involvement other than in the duodenum.

Plasmablastic lymphoma of the sphenoid bone in an immunocompetent patient: A diagnostic challenge.

ABSTRACT: Plasmablastic lymphoma is a rare type of highly aggressive B-cell non-Hodgkin lymphoma that usually occurs in immunocompromised patients and involves chiefly extra-nodal sites such as the oral cavity, jaw, gastrointestinal tract, soft tissue, bone, and skin. People above the age of 50 years are more commonly affected, with male predominance having a survival rate of 8 to 15 months. Here, we describe the case of a 48-year-old man who had an isolated plasmablastic lymphoma of the right sphenoid bone without any immunodeficiency. Plasmablastic lymphoma in immunocompetent patients at rare sites is a diagnostic challenge for both clinicians and pathologists because of vague clinical and histomorphology findings. This rare case report reemphasizes the utility of complete assimilation of clinical, histopathological, and immunohistochemical findings in such rare cases.

Discovery of a new class of reversible TEA domain transcription factor inhibitors with a novel binding mode.

The TEA domain (TEAD) transcription factor forms a transcription co-activation complex with the key downstream effector of the Hippo pathway, YAP/TAZ. TEAD-YAP controls the expression of Hippo-responsive genes involved in cell proliferation, development, and tumorigenesis. Hyperactivation of TEAD-YAP activities is observed in many human cancers and is associated with cancer cell proliferation, survival, and immune evasion. Therefore, targeting the TEAD-YAP complex has emerged as an attractive therapeutic approach. We previously reported that the mammalian TEAD transcription factors (TEAD1-4) possess auto-palmitoylation activities and contain an evolutionarily conserved palmitate-binding pocket (PBP), which allows small-molecule modulation. Since then, several reversible and irreversible inhibitors have been reported by binding to PBP. Here, we report a new class of TEAD inhibitors with a novel binding mode. Representative analog TM2 shows potent inhibition of TEAD auto-palmitoylation both in vitro and in cells. Surprisingly, the co-crystal structure of the human TEAD2 YAP-binding domain (YBD) in complex with TM2 reveals that TM2 adopts an unexpected binding mode by occupying not only the hydrophobic PBP, but also a new side binding pocket formed by hydrophilic residues. RNA-seq analysis shows that TM2 potently and specifically suppresses TEAD-YAP transcriptional activities. Consistently, TM2 exhibits strong antiproliferation effects as a single agent or in combination with a MEK inhibitor in YAP-dependent cancer cells. These findings establish TM2 as a promising small-molecule inhibitor against TEAD-YAP activities and provide new insights for designing novel TEAD inhibitors with enhanced selectivity and potency.

Pharmacological blockade of TEAD-YAP reveals its therapeutic limitation in cancer cells.

Targeting TEAD autopalmitoylation has been proposed as a therapeutic approach for YAP-dependent cancers. Here we show that TEAD palmitoylation inhibitor MGH-CP1 and analogues block cancer cell "stemness", organ overgrowth and tumor initiation in vitro and in vivo. MGH-CP1 sensitivity correlates significantly with YAP-dependency in a large panel of cancer cell lines. However, TEAD inhibition or YAP/TAZ knockdown leads to transient inhibition of cell cycle progression without inducing cell death, undermining their potential therapeutic utilities. We further reveal that TEAD inhibition or YAP/TAZ silencing leads to VGLL3-mediated transcriptional activation of SOX4/PI3K/AKT signaling axis, which contributes to cancer cell survival and confers therapeutic resistance to TEAD inhibitors. Consistently, combination of TEAD and AKT inhibitors exhibits strong synergy in inducing cancer cell death. Our work characterizes the therapeutic opportunities and limitations of TEAD palmitoylation inhibitors in cancers, and uncovers an intrinsic molecular mechanism, which confers potential therapeutic resistance.

Assessment of chin morphology in different skeletal dysplasia - A cross-sectional study.

Objective: The objective of the study is to evaluate the morphology of the symphyseal region of adult skeletal Class II and Class III malocclusion as compared with Skeletal Class I subjects. Materials and Methods: The symphyseal width and height were evaluated using data from 80 lateral cephalograms of the age range of 18 years to 25 years. Average growing Skeletal Class II (n = 30) and Class III (n = 20) subjects were used as a comparison group. Average growing normal occlusion samples (n = 30) were used as controls. Results: Alveolar height was similar in all groups. The width of the symphyseal region including basal width, the width of the cervical region of the lower central incisor at the cementoenamel junction, and symphysis width were found to be similar in all groups. There is no significant difference in gonial angle in both Class II and III groups as compared to control. Articular angle showed no significant difference. Mandibular incisor dentoalveolar height (L1-AH) was found to be significantly higher in the Class II group (P < 0.05). Conclusions: There are no definite morphological differences in the symphyseal region between average grower Class I, Class II, and Class III skeletal malocclusions except mandibular incisor dentoalveolar height (L1-AH) and incisor mandibular plane angle which is higher whereas ramus length and body length which is lesser in Class II group as compared with controls. Width of the cervical region of the lower central incisor at the cementoenamel junction (Id-Id') and incisor mandibular plane angle was lower than control in Class III subjects.

A nanoengineered topical transmucosal cisplatin delivery system induces anti-tumor response in animal models and patients with oral cancer.

Despite therapeutic advancements, oral cavity squamous cell carcinoma (OCSCC) remains a difficult disease to treat. Systemic platinum-based chemotherapy often leads to dose-limiting toxicity (DLT), affecting quality of life. PRV111 is a nanotechnology-based system for local delivery of cisplatin loaded chitosan particles, that penetrate tumor tissue and lymphatic channels while avoiding systemic circulation and toxicity. Here we evaluate PRV111 using animal models of oral cancer, followed by a clinical trial in patients with OCSCC. In vivo, PRV111 results in elevated cisplatin retention in tumors and negligible systemic levels, compared to the intravenous, intraperitoneal or intratumoral delivery. Furthermore, PRV111 produces robust anti-tumor responses in subcutaneous and orthotopic cancer models and results in complete regression of carcinogen-induced premalignant lesions. In a phase 1/2, open-label, single-arm trial (NCT03502148), primary endpoints of efficacy (≥30% tumor volume reduction) and safety (incidence of DLTs) of neoadjuvant PRV111 were reached, with 69% tumor reduction in ~7 days and over 87% response rate. Secondary endpoints (cisplatin biodistribution, loco-regional control, and technical success) were achieved. No DLTs or drug-related serious adverse events were reported. No locoregional recurrences were evident in 6 months. Integration of PRV111 with current standard of care may improve health outcomes and survival of patients with OCSCC.

AL101, a gamma-secretase inhibitor, has potent antitumor activity against adenoid cystic carcinoma with activated NOTCH signaling.

Adenoid cystic carcinoma (ACC) is an aggressive salivary gland malignancy with limited treatment options for recurrent or metastatic disease. Due to chemotherapy resistance and lack of targeted therapeutic approaches, current treatment options for the localized disease are limited to surgery and radiation, which fails to prevent locoregional recurrences and distant metastases in over 50% of patients. Approximately 20% of patients with ACC carry NOTCH-activating mutations that are associated with a distinct phenotype, aggressive disease, and poor prognosis. Given the role of NOTCH signaling in regulating tumor cell behavior, NOTCH inhibitors represent an attractive potential therapeutic strategy for this subset of ACC. AL101 (osugacestat) is a potent γ-secretase inhibitor that prevents activation of all four NOTCH receptors. While this investigational new drug has demonstrated antineoplastic activity in several preclinical cancer models and in patients with advanced solid malignancies, we are the first to study the therapeutic benefit of AL101 in ACC. Here, we describe the antitumor activity of AL101 using ACC cell lines, organoids, and patient-derived xenograft models. Specifically, we find that AL101 has potent antitumor effects in in vitro and in vivo models of ACC with activating NOTCH1 mutations and constitutively upregulated NOTCH signaling pathway, providing a strong rationale for evaluation of AL101 in clinical trials for patients with NOTCH-driven relapsed/refractory ACC.

PTEN and LKB1 are differentially required in Gli1-expressing mesenchymal cells to suppress gastrointestinal polyposis.

PTEN and LKB1 are intimately associated with gastrointestinal tumorigenesis. Mutations of PTEN or LKB1 lead to Cowden syndrome and Peutz-Jeghers syndrome characterized by development of gastrointestinal polyps. However, the cells of origin of these polyps and underlying mechanism remain unclear. Here, we reveal that PTEN or LKB1 deficiency in Gli1+ gut mesenchymal cells, but not intestinal epithelium, drives polyp formation histologically resembling polyposis in human patients. Mechanistically, although PTEN and LKB1 converge to regulate mTOR/AKT signaling in various tumor contexts, we find that mTOR is essential for PTEN-deletion-induced polyp formation but is largely dispensable for polyposis induced by mesenchymal LKB1 deficiency. Altogether, our studies identify Gli1-expressing mesenchymal cells as a common cell of origin for polyposis associated with PTEN and LKB1 and reveal their engagement of different downstream pathways in gut mesenchyme to suppress gastrointestinal tumorigenesis.