Detailing the ultrastructure's increase of prion protein in pancreatic adenocarcinoma.

BACKGROUND: Recent evidences have shown a relationship between prion protein (PrPc) expression and pancreatic ductal adenocarcinoma (PDAC). Indeed, PrPc could be one of the markers explaining the aggressiveness of this tumor. However, studies investigating the specific compartmentalization of increased PrPc expression within PDAC cells are lacking, as well as a correlation between ultrastructural evidence, ultrastructural morphometry of PrPc protein and clinical data. These data, as well as the quantitative stoichiometry of this protein detected by immuno-gold, provide a significant advancement in understanding the biology of disease and the outcome of surgical resection. AIM: To analyze quantitative stoichiometry and compartmentalization of PrPc in PDAC cells and to correlate its presence with prognostic data. METHODS: Between June 2018 and December 2020, samples from pancreatic tissues of 45 patients treated with pancreatic resection for a preoperative suspicion of PDAC at our Institution were collected. When the frozen section excluded a PDAC diagnosis, or the nodules were too small for adequate sampling, patients were ruled out from the present study. Western blotting was used to detect, quantify and compare the expression of PrPc in PDAC and control tissues, such as those of non-affected neighboring pancreatic tissue of the same patient. To quantify the increase of PrPc and to detect the subcellular compartmentalization of PrPc within PDAC cells, immuno-gold stoichiometry within specific cell compartments was analyzed with electron microscopy. Finally, an analysis of quantitative PrPc expression according to prognostic data, such as cancer stage, recurrence of the disease at 12 mo after surgery and recurrence during adjuvant chemotherapy was made. RESULTS: The amount of PrPc within specimen from 38 out of 45 patients was determined by semi-quantitative analysis by using Western blotting, which indicates that PrPc increases almost three-fold in tumor pancreatic tissue compared with healthy pancreatic regions [242.41 ± 28.36 optical density (OD) vs 95 ± 17.40 OD, P < 0.0001]. Quantitative morphometry carried out by using immuno-gold detection at transmission electron microscopy confirms an increased PrPc expression in PDAC ductal cells of all patients and allows to detect a specific compartmentalization of PrPc within tumor cells. In particular, the number of immuno-gold particles of PrPc was significantly higher in PDAC cells respect to controls, when considering the whole cell (19.8 ± 0.79 particles vs 9.44 ± 0.45, P < 0.0001). Remarkably, considering PDAC cells, the increase of PrPc was higher in the nucleus than cytosol of tumor cells, which indicates a shift in PrPc compartmentalization within tumor cells. In fact, the increase of immuno-gold within nuclear compartment exceeds at large the augment of PrPc which was detected in the cytosol (nucleus: 12.88 ± 0.59 particles vs 5.12 ± 0.32, P < 0.0001; cytosol: 7.74. ± 0.44 particles vs 4.3 ± 0.24, P < 0.0001). In order to analyze the prognostic impact of PrPc, we found a correlation between PrPc expression and cancer stage according to pathology results, with a significantly higher expression of PrPc for advanced stages. Moreover, 24 patients with a mean follow-up of 16.8 mo were considered. Immuno-blot analysis revealed a significantly higher expression of PrPc in patients with disease recurrence at 12 mo after radical surgery (360.71 ± 69.01 OD vs 170.23 ± 23.06 OD, P = 0.023), also in the subgroup of patients treated with adjuvant CT (368.36 ± 79.26 OD in the recurrence group vs 162.86 ± 24.16 OD, P = 0.028), which indicates a correlation with a higher chemo-resistance. CONCLUSION: Expression of PrPc is significantly higher in PDAC cells compared with control, with the protein mainly placed in the nucleus. Preliminary clinical data confirm the correlation with a poorer prognosis.

The occurrence of prion protein in surgically resected pancreatic adenocarcinoma.

BACKGROUND: Among the several new targets for the comprehension of the biology of pancreatic ductal adenocarcinoma (PDAC), Prion proteins (PrPc) deserve particular mention, since they share a marked neurotropism. Actually, PrPc could have also a role in tumorigenesis, as recently demonstrated. However, only few in vitro studies in cell cultures showed the occurrence of PrPc in PDAC cells. We aim to evaluate the presence of PrPc in vivo in PDAC tissues as a potential new biomarker. METHODS: Samples from tumors of 23 patients undergone pancreatic resections from July 2018 to May 2020 at our institution were collected and analyzed. Immunohistochemistry and western blotting of PDAC tissues were compared with control tissues. Immunohistochemistry was used also to evaluate the localization of PrPc and of CD155, a tumoral stem-cell marker. RESULTS: All cases were moderately differentiated PDAC, with perineural invasion (PNI) in 19/23 cases (83%). According to western-blot analysis, PrPc was markedly expressed in PDAC tissues (273.5 ± 44.63 OD) respect to controls (100 ± 28.35 OD, p = 0.0018). Immunohistochemistry confirmed these findings, with higher linear staining of PrPc in PDAC ducts (127.145 ± 7.56 µm vs 75.21 ± 5.01 µm, p < 0.0001). PrPc and CD155 exactly overlapped in ductal tumoral cells, highlighting the possible relationship of PrPc with cancer stemness. Finally, PrPc expression related with cancer stage and there was a potential correspondence with PNI. CONCLUSIONS: Our work provides evidence for increased levels of PrPc in PDAC. This might contribute to cancer aggressiveness and provides a potentially new biomarker. Work is in progress to decipher clinical implications.

Expression of 3-nitrotyrosine, a marker for peroxynitrite, in nasal polyps of nonatopic patients.

BACKGROUND: Several works have reported that nitric oxide and free oxygen radicals are up-regulated in nasal polyposis. This study aimed to assess the distribution of peroxynitrite in nasal polyps from nonatopic patients. Occurrence of peroxynitrite also was analyzed in relation with eosinophil infiltration and epithelial alterations. MATERIAL/METHODS: Hematoxylin and eosin staining was used for histologic study. Peroxynitrite was assessed by 3-nitrotyrosine immunohistochemistry. Quantitative evaluation was done by measuring the total number of eosinophils, the number of 3-nitrotyrosine-positive eosinophils, and the extension of the various epithelial alterations. RESULTS: Hematoxylin and eosin staining showed that the nasal polyp epithelium is characterized by progressive disruption or squamous metaplasia. In both cases, infiltrating eosinophils were found in the epithelium and lamina propria. The regions featuring epithelial disruption exhibited 3-nitrotyrosine immunostaining in eosinophils and epithelial cells; hematoxylin-and-eosin - stained eosinophils and 3-nitrotyrosine - positive eosinophils showed conspicuous variations in number. Within the regions featuring squamous metaplasia, 3-nitrotyrosine-positive eosinophils were rarely found, and the epithelium exhibited 3-nitrotyrosine only in the superficial cells. In these regions, hematoxylin-eosin - stained eosinophils showed slight variations in number. CONCLUSIONS: Peroxynitrite plays a pivotal role in the pathophysiology of nasal polyps. In fact, strong expression of peroxynitrite is associated with epithelial disruption, while poor expression of peroxynitrite is associated with squamous metaplasia. Peroxynitrite could influence afflux of eosinophils in the nasal mucosa; moreover, the total number of eosinophils is not critical in generating alterations of nasal polyp mucosa.

Curcumin protects Leydig cells of mice from damage induced by chronic alcohol administration.

BACKGROUND: It is known that alcohol consumption inhibits testosterone production and causes testicular atrophy. Curcumin is a phytochemical characterized by anti-inflammatory and antioxidant properties. It was also observed that curcumin protects the liver, pancreas, and nervous system from the toxic effects of alcohol consumption. The goal of this study was to determine if curcumin protects the Leydig cells of mice from chronic alcohol administration. MATERIAL/METHODS: Fifteen mice were treated daily for four weeks with a 3.0 g/kg of a 25% solution of alcohol. Fifteen mice received curcumin (80 mg/kg) added to the same alcohol solution. Fifteen mice were treated with a solution of maltose dextrins isocaloric to ethanol. Fifteen untreated mice were used as controls. RESULTS: In the alcohol-fed mice, numerous Leydig cells showed cytoplasmic rarefaction and increased diameter of the mitochondria. Several mitochondria had diameters three or more times larger than that of mitochondria from control mice. Numerous necrotic Leydig cells were observed. Testosterone plasma levels significantly decreased in comparison with control mice. In alcohol plus curcumin-treated mice the number of necrotic Leydig cells was reduced compared with alcohol-fed mice; the diameters of the mitochondria were significantly decreased. Testosterone plasma levels were not significantly different from those of the controls. CONCLUSION: This study demonstrates that curcumin exerts efficacious protection against damages caused in the Leydig cells of mice by chronic alcohol ingestion and that the preservation of mitochondrial structure and size in Leydig cells is a specific effect of curcumin.

MPTP-induced Parkinsonism is associated with damage to Leydig cells and testosterone loss.

Genital dysfunction and testosterone deficiency occur frequently in Parkinson's disease and represent a typical non-motor symptom of the disorder. Despite that, to our knowledge no study investigated whether at experimental level this can be reproduced with classic Parkinsonism-inducing neurotoxins. In this study we evaluated the effects produced in the testis following administration of the Parkinsonism-inducing neurotoxin 1-methyl, 4-phenyl, 1,2,3,6-tetrahydropyridine in mice. At 7 days following treatment, in the presence of a severe nigrostriatal dopamine depletion, we found a marked decrease in testosterone plasma levels in 1-methyl, 4-phenyl, 1,2,3,6-tetrahydropyridine-treated mice. Such testosterone loss occurred concomitantly with loss of Leydig cells and the presence of altered morphology in the interstitium with severe mitochondrial degeneration in spared Leydig cells. The loss of Leydig cells was accompanied by a marked decrease in TH immunohistochemistry and TH protein in the interstitium. This was accompanied by a significant decrease in norepinephrine levels in the testis. These effects shed novel light to understand genital dysfunction and testosterone deficiency in Parkinsonism, while offering a new experimental model to reproduce genital dysfunction in Parkinson's disease.