Biomimetic Trypsin-Responsive Structure-Bridged Mesoporous Organosilica Nanomedicine for Precise Treatment of Acute Pancreatitis.

Developing strategies to target injured pancreatic acinar cells (PACs) in conjunction with primary pathophysiology-specific pharmacological therapy presents a challenge in the management of acute pancreatitis (AP). We designed and synthesized a trypsin-cleavable organosilica precursor bridged by arginine-based amide bonds, leveraging trypsin's ability to selectively identify guanidino groups on arginine via Asp189 at the active S1 pocket and cleave the carboxy-terminal (C-terminal) amide bond via catalytic triads. The precursors were incorporated into the framework of mesoporous silica nanoparticles (MSNs) for encapsulating the membrane-permeable Ca2+ chelator BAPTA-AM with a high loading content (∼43.9%). Mesenchymal stem cell membrane coating and surface modification with PAC-targeting ligands endow MSNs with inflammation recruitment and precise PAC-targeting abilities, resulting in the highest distribution at 3 h in the pancreas with 4.7-fold more accumulation than that of naked MSNs. The outcomes transpired as follows: After bioinspired MSNs' skeleton biodegradation by prematurely and massively activated trypsin, BAPTA-AM was on-demand released in injured PACs, thereby effectively eliminating intracellular calcium overload (reduced Ca2+ level by 81.3%), restoring cellular redox status, blocking inflammatory cascades, and inhibiting cell necrosis by impeding the IκBα/NF-κB/TNF-α/IL-6 and CaMK-II/p-RIP3/p-MLKL/caspase-8,9 signaling pathways. In AP mice, a single dose of the formulation significantly restored pancreatic function (lipase and amylase reduced more by 60%) and improved the survival rate from 50 to 91.6%. The formulation offers a potentially effective strategy for clinical translation in AP treatment.

Complete pathological response to pembrolizumab in pretreated pancreatic acinar cell carcinoma.

BACKGROUND: Therapeutic approach used for pancreatic ductal adenocarcinoma is usually translated also for the rarer acinar counterpart, which shows a different mutational landscape nevertheless. While dMMR/MSI-H status is rare in the ductal histotype, it appears to be more prevalent in pancreatic acinar cell carcinoma (PACC). CASE PRESENTATION: We report the case of a patient with locally advanced MSI-H PACC in whom the treatment with the anti-PD-1 pembrolizumab, administered as third line, made possible surgical resection, achieving even an exceptional pathological complete response. CONCLUSIONS: Treatment of PACC should be tailored based on the peculiar molecular features that distinguish PACC from ductal adenocarcinoma. Evaluation of potentially therapeutically targetable alterations should be mandatory in case of PACC diagnosis.

Submandibular Gland Pathogenesis Following SARS-CoV-2 Infection and Implications for Xerostomia.

Although SARS-CoV-2 induces mucin hypersecretion in the respiratory tract, hyposalivation/xerostomia has been reported by COVID-19 patients. We evaluate the submandibular gland (SMGs) pathogenesis in SARS-CoV-2-infected K18-hACE2 mice, focusing on the impact of infection on the mucin production and structural integrity of acini, ductal system, myoepithelial cells (MECs) and telocytes. The spike protein, the nucleocapsid protein, hACE2, actin, EGF, TNF-α and IL-1ß were detected by immunofluorescence, and the Egfr and Muc5b expression was evaluated. In the infected animals, significant acinar hypertrophy was observed in contrast to ductal atrophy. Nucleocapsid proteins and/or viral particles were detected in the SMG cells, mainly in the nuclear membrane-derived vesicles, confirming the nuclear role in the viral formation. The acinar cells showed intense TNF-α and IL-1ß immunoexpression, and the EGF-EGFR signaling increased, together with Muc5b upregulation. This finding explains mucin hypersecretion and acinar hypertrophy, which compress the ducts. Dying MECs and actin reduction were also observed, indicating failure of contraction and acinar support, favoring acinar hypertrophy. Viral assembly was found in the dying telocytes, pointing to these intercommunicating cells as viral transmitters in SMGs. Therefore, EGF-EGFR-induced mucin hypersecretion was triggered by SARS-CoV-2 in acinar cells, likely mediated by cytokines. The damage to telocytes and MECs may have favored the acinar hypertrophy, leading to ductal obstruction, explaining xerostomia in COVID-19 patients. Thus, acinar cells, telocytes and MECs may be viral targets, which favor replication and cell-to-cell viral transmission in the SMG, corroborating the high viral load in saliva of infected individuals.

Successful curative treatment for a ruptured pancreatic acinar cell carcinoma by radical resection following modified FOLFIRINOX: a case report and literature review.

Pancreatic acinar cell carcinoma (PACC) is a rare pancreatic tumor type, and ruptured pancreatic tumors are rarer. Computed tomography (CT) in a 48-year-old man incidentally revealed a raptured pancreatic tail tumor. The patient was treated conservatively because he was asymptomatic, and his general condition was stable. After a detailed examination, the pancreatic tumor was diagnosed as raptured PACC. Considering the potential infiltration of tumor cells into the hematoma within the omental sac, our decision is to initiate chemotherapy as the primary course of action. A liquid biopsy was performed, and comprehensive genomic profiling of circulating tumor DNA showed a tumor BRCA2 mutation. Chemotherapy with modified FOLFIRINOX (mFFX) was selected as the first treatment. After seven courses of mFFX, the primary tumor diminished remarkably. At this time, the radical resection was performed via distal pancreatectomy with simultaneous resection of the gastric wall and colon, which had adhered strongly to the tumor. Histopathological examination revealed that the tumor had shrunk to less than 5% of its original size due to chemotherapy (Grade 3 of Evans Classification). Devising treatment strategies for ruptured pancreatic malignant tumors is challenging due to the worsening general condition caused by severe abdominal symptoms and intra-abdominal bleeding. In this context, this case-report documents a rare instance of raptured PACC with a tumor BRCA2 mutation that underwent radical resection following mFFX treatment.

Liquid-based cytology features of pancreatic acinar cell carcinoma: comparison with other non-ductal neoplasms of the pancreas.

Background: Acinar cell carcinoma (ACC) is a rare malignant epithelial neoplasm, which shares many cytomorphological features with other non-ductal pancreatic neoplasms such as pancreatic neuroendocrine neoplasm (PanNEN) and solid-pseudopapillary neoplasm (SPN). Due to the relative rarity of these tumors, pathologists are less familiar with the cytological features, especially on liquid-based cytology (LBC) which has been relatively recently introduced for endoscopic ultrasound-guided fine needle aspiration specimens. Methods: We evaluated the detailed cytological features of 15 histologically confirmed ACC (7 conventional smears [CS], 8 LBC), and compared them with the LBC features of SPN (n = 9) and PanNEN (n = 9). Results: Compared with CS, LBCs of ACC demonstrated significantly less bloody background. All ACCs demonstrated prominent nucleoli and macronucleoli on LBC. On comparison with the LBC features of SPN and PanNEN, most ACCs demonstrated a necrotic background with apoptotic debris while PanNEN and SPN did not show these features. Acinar structures were predominantly observed in ACC, while frequent pseudopapillary structures were seen only in SPN. Prominent nucleoli and macronucleoli were only seen in ACC. Conclusions: ACC had characteristic cytological features that could be observed on LBC preparations, such as high cellularity, necrotic/apoptotic background, nuclear tangles, acinar arrangement of cells, and macronucleoli. These findings also help distinguish ACC from PanNEN and SPN on LBC. It is important to be familiar with these features, as an accurate diagnosis on endoscopic ultrasound-guided fine needle aspiration cytology would have impact on the management of the patient.

Distribution of TRPC3 and TRPC6 in the human exocrine and endocrine pancreas.

BACKGROUND: Expression and function of TRPC3 and TRPC6 in the pancreas is a controversial topic. Investigation in human tissue is seldom. We aimed to provide here a detailed description of the distribution of TRPC3 and TRPC6 in the human exocrine and endocrine pancreas. METHODS: We collected healthy samples from cadavers (n = 4) and visceral surgery (n = 4) to investigate the respective expression profiles using immunohistochemical tracing with knockout-validated antibodies. RESULTS: TRPC3- and TRPC6-proteins were detected in different pancreatic structures including acinar cells, as well as epithelial ductal cells from intercalate, intralobular, and interlobular ducts. Respective connective tissue layers appeared unstained. Endocrine islets of Langerhans were clearly and homogenously immunolabeled by the anti-TRPC3 and anti-TRPC6 antibodies. Insular α, ß, γ, and δ cells were conclusively stained, although no secure differentiation of cell types was performed. CONCLUSIONS: Due to aforementioned antibody specificity verification, protein expression in the immunolabeled localizations can be accepted. Our study in human tissue supports previous investigations especially with respect to acinar and insular α and ß cells, while other localizations are here reported for the first time to express TRPC3 and TRPC6, ultimately warranting further research.

Reappraising imaging features of pancreatic acinar cystic transformation: be aware of differential diagnoses.

OBJECTIVES: Imaging features of pancreatic acinar cystic transformation (ACT) have been published. We aimed to describe the clinical and radiological characteristics of patients with a presumed pancreatic ACT diagnosis, reappraising the value of these published imaging criteria. MATERIALS AND METHODS: Single-center retrospective study (2003-2021) of consecutive patients with a presumed diagnosis of ACT as suggested by the local expert multidisciplinary case review board. Patients without available imaging (CT or MRI) for review were excluded. Patients were classified into "certain" ACT (if ≥ 2 imaging criteria and no differential diagnosis) or "uncertain" ACT (if ≥ 1 imaging criteria and suggested differential diagnoses). RESULTS: Sixty-four patients (35 males, [55%]) were included. ACT was considered "certain" for 34 patients (53%) and "uncertain" for 30 patients (47%). The number of ACT criteria did not differ between groups, with 91.2% of patients with ≥ 3 ACT imaging criteria in the "certain" group vs 93.3% in the "uncertain" group (p = 0.88). In the "uncertain" group, the main suggested differentials were branch-duct intraductal papillary mucinous neoplasm (18/30 patients, 60%), calcifying chronic pancreatitis (8/30 patients, 27%), both (three patients, 10%) and serous cystadenoma (one patient, 3%). Calcifications were significantly more frequent in the "uncertain" group (89% vs 63% in the "certain" group, p = 0.02). CONCLUSION: Published ACT imaging criteria are frequently associated with features suggesting differential diagnoses. They appear insufficient to reach a final diagnosis in a subset of patients. CLINICAL RELEVANCE STATEMENT: ACT displays a heterogeneous morphological imaging presentation challenging the non-invasive diagnostic work-up. Physicians' and radiologists' awareness of this entity is important to better understand its natural history and improve non-invasive diagnostic criteria. KEY POINTS: The criteria to help diagnose ACT are frequently associated with features suggestive of differentials. The main alternatives suggested when ACT diagnosis was "uncertain" were branch-duct intraductal papillary mucinous neoplasm and calcifying chronic pancreatitis. Published ACT diagnostic imaging criteria can be insufficient for a definite non-invasive diagnosis.

Inhibition Effects of Acetylsalicylic Acid with Nitric Oxide (NO-ASA) on Neoplastic Changes in the Exocrine Pancreas Acinar Cells of the Azaserine Injected Rats.

BACKGROUND: Atypical acinar cell foci (AACF) seen in pancreatic cancer are fatal and have been studied with some causative agents. However, for the first time, the effect of acetylsalicylic acid with nitric oxide (NO-ASA) on AACF was examined in this study. Although NO-ASA has very successful inhibitory effects against some types of cancer, it has not been investigated whether they can exert their inhibition effects on AACFs. METHODS: For experimental purposes, 21 14-day-old male Wistar albino rats were used. Azaserine (30 mg/kg) was dissolved in 0.9% NaCl solution and injected intraperitoneally (i.p.) into 14 rats, except for the Control group (Cont) rats, for three weeks. Rats that were injected with azaserine once a week for three weeks and those that did not receive treatment were divided into experimental groups. 15 days after the end of the azaserine injection protocol, NO-ASA was applied to azaserine with NO-ASA (Az+NO-ASA) group rats three consecutive times with an interval of 15 days by gavage. At the end of the 5-month period, pancreatic tissue was dissected and weighed. Pancreas preparations prepared from histological sections were examined for AACF burden and analyzed via a video image analyzer. One-way analysis of variance (ANOVA) non-parametric statistical analyses were performed to test whether there was a difference between the averages of the experimental and Control groups. RESULTS: AACF burden in both groups injected with azaserine was found to be statistically significant in all categories compared to that of the Control group (p < 0.05). The average Calculated Estimated average AACF volume (mm3) values, the Calculated estimated average AACF diameter (µm), the Estimated average number of AACF per unit volume, AACF rate as a % of Calculated Organ Volume were higher in the AzCont group rats than in the Az+NO-ASA group, when compared, and there was an important level statistical difference between the groups (p < 0.05). It was determined that for all parameters AACFs load in Az+NO-ASA group rats were significantly reduced compared to that of AzCont group rats (p < 0.05). CONCLUSIONS: We observed that, as a result of the NO-ASA application, the experimental AACF focus ratio created by azaserine injection was significantly inhibited. The inhibitory effect of AACFs in Az+NO-ASA group rats may have resulted from the significant and independent chemopreventive and/or chemotherapeutic activity of NO-ASA against exocrine pancreatic AACF foci.

A case of BRCA1-mutated giant pancreatic acinar cell carcinoma successfully treated with modified FOLFIRINOX therapy and radical resection.

Pancreatic acinar cell carcinoma (PACC) is a rare type of pancreatic cancer; further, its pathogenesis and treatment strategies remain unclear. We report the case of a 70-year-old man who presented with a chief complaint of abdominal distention. Computed tomography scans revealed a large lobulated mass (tumor diameter: 150 mm) in the pancreatic body tail, which was diagnosed as a PACC through endoscopic ultrasonography fine needle aspiration. The other imaging modalities did not reveal distant metastases, and the tumor was classified as resectable. Neoadjuvant chemotherapy was planned after staging laparoscopy ruled out microscopic distant metastasis. First-line chemotherapy with gemcitabine + nab-paclitaxel failed due to tumor growth and worsening abdominal distention. Evaluation using the BRACAnalysis® device indicated that the patient was positive for BRCA1 mutation. Second-line modified FOLFIRINOX (mFFX) resulted in a marked decrease in elastase 1 levels; moreover, a partial antitumor response was observed, which prompted radical resection. After distal pancreatectomy, the patient has survived for 3.5 years without recurrence. BRCA-mutated pancreatic cancer is more likely to respond to mFFX, including platinum, and BRCA mutations have been reported to be highly prevalent in PACC. It is important to evaluate the presence of BRCA mutations in patients with PACC prior to treatment.

Berberine inhibits intracellular Ca2+ signals in mouse pancreatic acinar cells through M3 muscarinic receptors: Novel target, mechanism, and implication.

Berberine, a natural isoquinoline alkaloid, exhibits a variety of pharmacological effects, but the pharmacological targets and mechanisms remain elusive. Here, we report a novel finding that berberine inhibits acetylcholine (ACh)-induced intracellular Ca2+ oscillations, mediated through an inhibition of the muscarinic subtype 3 (M3) receptor. Patch-clamp recordings and confocal Ca2+ imaging were applied to acute dissociated pancreatic acinar cells prepared from CD1 mice to examine the effects of berberine on ACh-induced Ca2+ oscillations. Whole-cell patch-clamp recordings showed that berberine (from 0.1 to 10 µM) reduced ACh-induced Ca2+ oscillations in a concentration-dependent manner, and this inhibition also depended on ACh concentrations. The inhibitory effect of berberine neither occurred in intracellular targets nor extracellular cholecystokinin (CCK) receptors, chloride (Cl-) channels, and store-operated Ca2+ channels. Together, the results demonstrate that berberine directly inhibits the muscarinic M3 receptors, further confirmed by evidence of the interaction between berberine and M3 receptors in pancreatic acinar cells.

Pathological complete response with FOLFIRINOX therapy for recurrence of pancreatic acinar cell carcinoma.

Pancreatic acinar cell carcinoma (PACC) is a very rare subtype of pancreatic cancer. Due to small number of patients, no standard chemotherapy protocol has been established. We experienced an extremely rare case of PACC with liver metastasis that showed a pathological complete response after modified FOLFIRINOX (mFFX) therapy. A 42-year-old man who underwent distal pancreatectomy for an 80 mm tumor at the pancreatic tail 3 years ago was referred to our hospital in September 2017 for the treatment of a recurrent liver tumor. Percutaneous biopsy revealed an acinar-neuroendocrine carcinoma, similar to the surgical specimen. He received eight cycles of irinotecan plus cisplatin chemotherapy. However, the tumor increased in size, and treatment was switched to mFFX therapy. The tumor in the liver shrank remarkably after nine cycles of mFFX therapy. Conversion surgery was selected, and the patient underwent hepatic left and caudate lobectomy 8 months after administration of mFFX. The resected specimen showed no viable tumor cells, indicating a pathological complete response. The histological diagnosis was reconsidered, and PACC was finally diagnosed via an additional immunohistological review. The patient has remained well with no recurrence for 6 years after surgery. This study is the first to report a case of pathological complete response with mFFX therapy for the recurrence of PACC.

The response of pancreatic acinar cell carcinoma to platinum and olaparib therapy in a germline BRCA2 variant carrier: case report and literature review.

A 73-year-old Japanese man with a history of distal biliary cancer treated by pancreatoduodenectomy developed pancreatic acinar cell carcinoma (PACC) treated by remnant pancreatectomy and adjuvant chemotherapy. Thirteen months after surgery, multiple liver metastases developed and FOLFOX chemotherapy was initiated. Based on the PACC diagnosis and a positive family history for breast and ovarian cancer genetic testing was performed which revealed a pathogenic germline BRCA2 variant (c.8629G > T, p.Glu2877Ter). Olaparib therapy was initiated and the metastases responded well (partial response). PACC is a BRCA2-associated cancer which may respond well to PARP inhibitors.

Paediatric pancreatic acinar cell carcinoma with a novel SEC31A-BRAF fusion gene.

Paediatric pancreatic acinar cell carcinoma (PACC) presents a diagnostic challenge, often confused with pancreatoblastoma (PB) due to its rarity. It is crucial to differentiate between PB and PACC, given their distinct therapeutic strategies and prognoses. Histologically, the absence of squamoid nests and scarcity of tumor mesenchyme support PACC. Conversely, the identification of a BRAF alteration leans towards PACC. Here, we present the case of an 8-year-old girl with a well-defined mass in the pancreas. The tumor exhibited a SEC31A-BRAF fusion gene and amplification of 18p, showcasing unequivocal acinar differentiation and a minor degree of neuroendocrine differentiation. Additionally, the tumor displayed scant fibrous stroma, and an absence of squamoid nests, further supporting PACC. Notably, this is the first reported instance of a solid tumor featuring a SEC31A-BRAF gene fusion. The discovery of this novel fusion gene expands our understanding of BRAF fusion partner profiles, particularly in the context of paediatric PACC.

A case of acinar cell carcinoma originating from the accessory papilla of the duodenum.

CASE PRESENTATION: A 61-year-old female was referred to our hospital with a neoplastic lesion in the duodenum. Computed tomography with contrast enhancement revealed a 10-mm tumor in the duodenum. Upper gastrointestinal endoscopy revealed a submucosal tumor-like lesion in the descending part of the duodenum. Endoscopic ultrasound revealed a well-defined hypoechoic tumor. Biopsy and immunohistochemical findings including negative Synaptophysin and Chromogranin A staining and positive Trypsin and BCL10 staining suggested a carcinoma with acinar cell differentiation. Pancreatoduodenectomy was performed, and the resected specimen had a 15-mm solid nodule in the submucosal layer of the duodenum. Pancreatogram of the resected specimen revealed a tumor localized in the accessory papilla region. In histopathological examination, the tumor was found in the submucosa of the duodenum with pancreatic tissue present nearby, and these were separated from the pancreatic parenchyma by the duodenal muscle layer. These findings led to a diagnosis of acinar cell carcinoma originating from the accessory papilla of the duodenum. CONCLUSION: Acinar cell carcinoma originating from the accessory papilla of the duodenum is exceptionally rare, with no reported cases to date. The origin was considered to be pancreatic tissue located in the accessory papilla region.

Acinar content at pancreatic resection margin is significantly associated with clinically relevant pancreatic fistula after partial pancreatoduodenectomy.

BACKGROUND: This study aimed to evaluate the clinical significance of acinar content at the pancreatic resection margin after partial pancreatoduodenectomy (PD). METHODS: A total of 228 consecutive patients undergoing PD were included for analysis. Resection margins were assessed for acinar, fibrosis, and fat contents by 2 pathologists blinded to the patients' clinical data. Univariate and multivariable analyses of possible predictors for clinically relevant postoperative pancreatic fistula (cr-POPF) were performed. RESULTS: The median acinar, fibrosis, and fat contents were 70% (IQR, 25%-82%), 13% (IQR, 5%-40%), and 15% (IQR, 9.25%-25%), respectively. The rates of cr-POPF were significantly higher in patients with an acinar content of >70% than in patients with an acinar content of ≤70% (26.4% vs 5.5%, respectively; P < .001). In addition, the rates of postoperative hyperamylasemia (POH) were significantly higher in patients with an acinar content of ≥70% than in patients with an acinar content of ≤70% (55.2% vs 13.8%, respectively; P < .001). The median fat content did not differ between patients with and without cr-POPF (13.0% [IQR, 7.5%-20.0%] vs 15.0% [IQR, 10.0%-30.0%], respectively; P = .06). An acinar content of >70% at the pancreatic resection margin (odds ratio [OR], 4.85; 95% CI, 1.61-14.58; P = .005) and a soft pancreatic texture (OR, 2.82; 95% CI, 1.02-7.76; P = .046) were independent predictive factors of cr-POPF in the multivariable analysis. CONCLUSION: An acinar content of ≥70% at the pancreatic resection margin was a significant predictive factor for cr-POPF after PD and was also significantly associated with POH, a precursor of cr-POPF after PD in many cases. Fatty infiltration of the pancreatic resection margin was not associated with cr-POPF.

Acute pancreatitis: pathogenesis and emerging therapies.

Acute pancreatitis is a severe inflammatory disorder with limited treatment options. Improved understanding of disease mechanisms has led to new and potential therapies. Here we summarize what we view as some of the most promising new therapies for treating acute pancreatitis, emphasizing the rationale of specific treatments based on disease mechanisms. Targeted pharmacologic interventions are highlighted. We explore potential treatment benefits and risks concerning reducing acute injury, minimizing complications, and improving long-term outcomes. Mechanisms associated with acute pancreatitis initiation, perpetuation, and reconstitution are highlighted, along with potential therapeutic targets and how these relate to new treatments.

Long-term safety and efficacy outcomes of valoctocogene roxaparvovec gene transfer up to 6 years post-treatment.

INTRODUCTION: Valoctocogene roxaparvovec uses an adeno-associated virus serotype 5 (AAV5) vector to transfer a factor VIII (FVIII) coding sequence to individuals with severe haemophilia A, providing bleeding protection. AIM: To assess safety and efficacy of valoctocogene roxaparvovec 5-6 years post-treatment. METHODS: In a phase 1/2 trial, adult male participants with severe haemophilia A (FVIII ≤1 IU/dL) without FVIII inhibitors or anti-AAV5 antibodies received valoctocogene roxaparvovec and were followed for 6 (6 × 1013 vg/kg; n = 7) and 5 (4 × 1013 vg/kg; n = 6) years. Safety, including investigation of potential associations between a malignancy and gene therapy, and efficacy are reported. RESULTS: No new treatment-related safety signals emerged. During year 6, a participant in the 6 × 1013  vg/kg cohort was diagnosed with grade 2 parotid gland acinar cell carcinoma; definitive treatment was uncomplicated parotidectomy with lymph node dissection. Target enrichment sequencing of tumour and adjacent healthy tissue revealed low vector integration (8.25 × 10-5 per diploid cell). Integrations were not elevated in tumour samples, no insertions appeared to drive tumorigenesis, and no clonal expansion of integration-containing cells occurred. During all follow-ups, >90% decreases from baseline in annualised treated bleeds and FVIII infusion rates were maintained. At the end of years 6 and 5, mean FVIII activity (chromogenic assay) was 9.8 IU/dL (median, 5.6 IU/dL) and 7.6 IU/dL (median, 7.1 IU/dL) for the 6 × 1013 and 4 × 1013 vg/kg cohorts, respectively, representing proportionally smaller year-over-year declines than earlier timepoints. CONCLUSIONS: Valoctocogene roxaparvovec safety and efficacy profiles remain largely unchanged; genomic investigations showed no association with a parotid tumour.

Immunolocalization patterns of histone-deacetylases in salivary glands of mice during postnatal development.

OBJECTIVE: Histone-deacetylases (HDACs) are epigenetic modulators involved in the control of gene expression. No data are available on the expression or subcellular localization of HDACs in salivary glands. The present study aims to examine the subcellular distribution of HDACs in salivary glands during postnatal development. DESIGN: The major salivary glands of C57/BL6 mice were separately removed at 10, 25, 30,60 and 90 days after birth. Hematoxylin-eosin (H&E) and immunohistochemical staining were performed for HDACs. Gene Expression of HDACs in C57BL/6. NOD-Aec1Aec2 mice salivary glands during the development of Sjögren's syndrome-like illness were also analyzed by using the gene expression datasets (GSE 15640). RESULTS: In the mice salivary gland, HDACs were found to have different localization patterns at various stages of development (10, 25, 30, 60, and 90 days). Apart from HDAC6, ductal cells of salivary glands were the primary sites for HDAC localization. HDAC2, 8, 5, 10 and 11 were expressed at high levels in the salivary gland after birth while HDAC6 showed no expression during postnatal development. This suggests that these HDAC subtypes may have different roles in salivary gland function. In the context of Sjögren's syndrome-like illness, HDAC 2, 8 and 10 showed low expression while HDAC1, 6,5,3 and 11 had relatively high expression in the salivary gland. CONCLUSIONS: This study has provided an important reference for understanding the spatiotemporal-specific expression of HDACs in the salivary gland. These results offer new clues for the experimenters and hold promise for developing innovative therapeutic strategies for salivary gland-related diseases.

DNA Methylation Profiling Enables Accurate Classification of Nonductal Primary Pancreatic Neoplasms.

BACKGROUND & AIMS: Cytologic and histopathologic diagnosis of non-ductal pancreatic neoplasms can be challenging in daily clinical practice, whereas it is crucial for therapy and prognosis. The cancer methylome is successfully used as a diagnostic tool in other cancer entities. Here, we investigate if methylation profiling can improve the diagnostic work-up of pancreatic neoplasms. METHODS: DNA methylation data were obtained for 301 primary tumors spanning 6 primary pancreatic neoplasms and 20 normal pancreas controls. Neural Network, Random Forest, and extreme gradient boosting machine learning models were trained to distinguish between tumor types. Methylation data of 29 nonpancreatic neoplasms (n = 3708) were used to develop an algorithm capable of detecting neoplasms of non-pancreatic origin. RESULTS: After benchmarking 3 state-of-the-art machine learning models, the random forest model emerged as the best classifier with 96.9% accuracy. All classifications received a probability score reflecting the confidence of the prediction. Increasing the score threshold improved the random forest classifier performance up to 100% with 87% of samples with scores surpassing the cutoff. Using a logistic regression model, detection of nonpancreatic neoplasms achieved an area under the curve of >0.99. Analysis of biopsy specimens showed concordant classification with their paired resection sample. CONCLUSIONS: Pancreatic neoplasms can be classified with high accuracy based on DNA methylation signatures. Additionally, non-pancreatic neoplasms are identified with near perfect precision. In summary, methylation profiling can serve as a valuable adjunct in the diagnosis of pancreatic neoplasms with minimal risk for misdiagnosis, even in the pre-operative setting.

Rare, Tightly-Bound, Multi-Cellular Clusters in the Pancreatic Ducts of Adult Mice Function Like Progenitor Cells and Survive and Proliferate After Acinar Cell Injury.

Pancreatic ductal progenitor cells have been proposed to contribute to adult tissue maintenance and regeneration after injury, but the identity of such ductal cells remains elusive. Here, from adult mice, we identify a near homogenous population of ductal progenitor-like clusters, with an average of 8 cells per cluster. They are a rare subpopulation, about 0.1% of the total pancreatic cells, and can be sorted using a fluorescence-activated cell sorter with the CD133highCD71lowFSCmid-high phenotype. They exhibit properties in self-renewal and tri-lineage differentiation (including endocrine-like cells) in a unique 3-dimensional colony assay system. An in vitro lineage tracing experiment, using a novel HprtDsRed/+ mouse model, demonstrates that a single cell from a cluster clonally gives rise to a colony. Droplet RNAseq analysis demonstrates that these ductal clusters express embryonic multipotent progenitor cell markers Sox9, Pdx1, and Nkx6-1, and genes involved in actin cytoskeleton regulation, inflammation responses, organ development, and cancer. Surprisingly, these ductal clusters resist prolonged trypsin digestion in vitro, preferentially survive in vivo after a severe acinar cell injury and become proliferative within 14 days post-injury. Thus, the ductal clusters are the fundamental units of progenitor-like cells in the adult murine pancreas with implications in diabetes treatment and tumorigenicity.