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Proteasome particle-rich structures are widely present in human epithelial neoplasms: correlative light, confocal and electron microscopy study.

Necchi V, Sommi P, Vanoli A, Manca R, Ricci V, Solcia E - PLoS ONE (2011)

Bottom Line: Particle lysis and loss of proteasome distinctive immunoreactivities were seen in some tumour cell PaCSs, possibly ending in sequestosomes or autophagic bodies.It is concluded that PaCSs are widely represented in human neoplasms and that both non-infectious and infectious factors activating the ubiquitin-proteasome system are likely to be involved in their origin.PaCS detection might help clarify the role of the ubiquitin-proteasome system in carcinogenesis.

View Article: PubMed Central - PubMed

Affiliation: Department of Human Pathology and Genetics, University of Pavia, Pavia, Italy.

ABSTRACT
A novel cytoplasmic structure has been recently characterized by confocal and electron microscopy in H. pylori-infected human gastric epithelium, as an accumulation of barrel-like proteasome reactive particles colocalized with polyubiquitinated proteins, H. pylori toxins and the NOD1 receptor. This proteasome particle-rich cytoplasmic structure (PaCS), a sort of focal proteasome hyperplasia, was also detected in dysplastic cells and was found to be enriched in SHP2 and ERK proteins, known to play a role in H. pylori-mediated gastric carcinogenesis. However, no information is available on its occurrence in neoplastic growths. In this study, surgical specimens of gastric cancer and various other human epithelial neoplasms have been investigated for PaCSs by light, confocal and electron microscopy including correlative confocal and electron microscopy (CCEM). PaCSs were detected in gastric cohesive, pulmonary large cell and bronchioloalveolar, thyroid papillary, parotid gland, hepatocellular, ovarian serous papillary, uterine cervix and colon adenocarcinomas, as well as in pancreatic serous microcystic adenoma. H. pylori bodies, their virulence factors (VacA, CagA, urease, and outer membrane proteins) and the NOD1 bacterial proteoglycan receptor were selectively concentrated inside gastric cancer PaCSs, but not in PaCSs from other neoplasms which did, however, retain proteasome and polyubiquitinated proteins reactivity. No evidence of actual microbial infection was obtained in most PaCS-positive neoplasms, except for H. pylori in gastric cancer and capsulated bacteria in a colon cancer case. Particle lysis and loss of proteasome distinctive immunoreactivities were seen in some tumour cell PaCSs, possibly ending in sequestosomes or autophagic bodies. It is concluded that PaCSs are widely represented in human neoplasms and that both non-infectious and infectious factors activating the ubiquitin-proteasome system are likely to be involved in their origin. PaCS detection might help clarify the role of the ubiquitin-proteasome system in carcinogenesis.

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Pancreatic serous microcystic adenoma.(A, B) Formalin-fixed paraffin sections; note the clear, apparently “empty” cytoplasm of most cells in A (hematoxylin-eosin, 1,000x) and the poor reactivity in B to proteasome immunofluorescence under confocal microscopy (blue: nuclei; green: proteasome; 800x). (C, D) Semithin aldehyde-osmium fixed resin sections from the same tumour as in A and B, show abundant cytoplasmic PaCSs metachromatically stained pink with toluidine blue (C, 1,000x) and extensively proteasome immunofluorescent under confocal microscopy (D, green: proteasome; 500x). (E) CCEM showing proteasome immunofluorescent PaCS (5,000x); the same specimen under TEM only (F, 5,000x), boxed area enlarged in G (50,000x) shows the PaCS particulate pattern with 20S proteasome immunogold reactivity. (H, I) TEM of another specimen of the same tumour in H (5,000x), boxed area enlarged in I (30,000x) and further enlarged in the inset (50,000x) to show PaCS particulate ultrastructure and 19S proteasome immunogold.
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pone-0021317-g002: Pancreatic serous microcystic adenoma.(A, B) Formalin-fixed paraffin sections; note the clear, apparently “empty” cytoplasm of most cells in A (hematoxylin-eosin, 1,000x) and the poor reactivity in B to proteasome immunofluorescence under confocal microscopy (blue: nuclei; green: proteasome; 800x). (C, D) Semithin aldehyde-osmium fixed resin sections from the same tumour as in A and B, show abundant cytoplasmic PaCSs metachromatically stained pink with toluidine blue (C, 1,000x) and extensively proteasome immunofluorescent under confocal microscopy (D, green: proteasome; 500x). (E) CCEM showing proteasome immunofluorescent PaCS (5,000x); the same specimen under TEM only (F, 5,000x), boxed area enlarged in G (50,000x) shows the PaCS particulate pattern with 20S proteasome immunogold reactivity. (H, I) TEM of another specimen of the same tumour in H (5,000x), boxed area enlarged in I (30,000x) and further enlarged in the inset (50,000x) to show PaCS particulate ultrastructure and 19S proteasome immunogold.

Mentions: In accordance with previous studies [1], PaCSs were identified in aldehyde-osmium fixed, resin embedded specimens of H. pylori-infected gastric foveolar epithelium as well-defined cytoplasmic areas metachromatically stained pink by toluidine blue and selectively immunofluorescent with antibodies directed against H. pylori proteins, proteasome (Figure 1A) or polyubiquitinated proteins. Under electron microscopy, PaCSs showed characteristic barrel-like particles, about 13 nm thick and 15 to 40 nm long, with an inner punctate substructure, and selective immunogold reactivity for proteasome (Figure 1B and C), polyubiquitinated proteins, NOD1, VacA, CagA, urease and OMPs, but not for p62 protein or the lysosomal marker cathepsin D. Using the same procedures, PaCSs were also identified in two of five gastric gland-forming (cohesive, so-called ‘intestinal’) cancers, with all the structural and cytochemical patterns shown in non-tumour gastric epithelium (Figure 1D–M). In addition, cytoplasmic areas reproducing PaCS ultrastructure and proteasome as well as ubiquitinated proteins reactivity, though without H. pylori products and NOD1, were detected in pancreatic serous microcystic adenoma (Figure 2), basal cell parotid gland cancer (Figure 3), ovarian serous papillary, uterine cervical and thyroid papillary carcinoma (Figure 4), pulmonary large cell, bronchioloalveolar and hepatocellular carcinoma (Figure 5A–E), apparently in the absence of actual infection. On the other hand, both PaCSs and capsulated (Gram-positive) bacteria were detected inside one case of colon carcinoma (Figure 5F–H). PaCSs were not observed in gastric diffuse, ovarian mucinous and breast ductal cancers. Nuclear areas filled with proteasome-like particles, ultrastructurally and cytochemically indistinguishable from those of PaCS, were also found in one case of parotid cancer (Figure 3F and G).


Proteasome particle-rich structures are widely present in human epithelial neoplasms: correlative light, confocal and electron microscopy study.

Necchi V, Sommi P, Vanoli A, Manca R, Ricci V, Solcia E - PLoS ONE (2011)

Pancreatic serous microcystic adenoma.(A, B) Formalin-fixed paraffin sections; note the clear, apparently “empty” cytoplasm of most cells in A (hematoxylin-eosin, 1,000x) and the poor reactivity in B to proteasome immunofluorescence under confocal microscopy (blue: nuclei; green: proteasome; 800x). (C, D) Semithin aldehyde-osmium fixed resin sections from the same tumour as in A and B, show abundant cytoplasmic PaCSs metachromatically stained pink with toluidine blue (C, 1,000x) and extensively proteasome immunofluorescent under confocal microscopy (D, green: proteasome; 500x). (E) CCEM showing proteasome immunofluorescent PaCS (5,000x); the same specimen under TEM only (F, 5,000x), boxed area enlarged in G (50,000x) shows the PaCS particulate pattern with 20S proteasome immunogold reactivity. (H, I) TEM of another specimen of the same tumour in H (5,000x), boxed area enlarged in I (30,000x) and further enlarged in the inset (50,000x) to show PaCS particulate ultrastructure and 19S proteasome immunogold.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3117888&req=5

pone-0021317-g002: Pancreatic serous microcystic adenoma.(A, B) Formalin-fixed paraffin sections; note the clear, apparently “empty” cytoplasm of most cells in A (hematoxylin-eosin, 1,000x) and the poor reactivity in B to proteasome immunofluorescence under confocal microscopy (blue: nuclei; green: proteasome; 800x). (C, D) Semithin aldehyde-osmium fixed resin sections from the same tumour as in A and B, show abundant cytoplasmic PaCSs metachromatically stained pink with toluidine blue (C, 1,000x) and extensively proteasome immunofluorescent under confocal microscopy (D, green: proteasome; 500x). (E) CCEM showing proteasome immunofluorescent PaCS (5,000x); the same specimen under TEM only (F, 5,000x), boxed area enlarged in G (50,000x) shows the PaCS particulate pattern with 20S proteasome immunogold reactivity. (H, I) TEM of another specimen of the same tumour in H (5,000x), boxed area enlarged in I (30,000x) and further enlarged in the inset (50,000x) to show PaCS particulate ultrastructure and 19S proteasome immunogold.
Mentions: In accordance with previous studies [1], PaCSs were identified in aldehyde-osmium fixed, resin embedded specimens of H. pylori-infected gastric foveolar epithelium as well-defined cytoplasmic areas metachromatically stained pink by toluidine blue and selectively immunofluorescent with antibodies directed against H. pylori proteins, proteasome (Figure 1A) or polyubiquitinated proteins. Under electron microscopy, PaCSs showed characteristic barrel-like particles, about 13 nm thick and 15 to 40 nm long, with an inner punctate substructure, and selective immunogold reactivity for proteasome (Figure 1B and C), polyubiquitinated proteins, NOD1, VacA, CagA, urease and OMPs, but not for p62 protein or the lysosomal marker cathepsin D. Using the same procedures, PaCSs were also identified in two of five gastric gland-forming (cohesive, so-called ‘intestinal’) cancers, with all the structural and cytochemical patterns shown in non-tumour gastric epithelium (Figure 1D–M). In addition, cytoplasmic areas reproducing PaCS ultrastructure and proteasome as well as ubiquitinated proteins reactivity, though without H. pylori products and NOD1, were detected in pancreatic serous microcystic adenoma (Figure 2), basal cell parotid gland cancer (Figure 3), ovarian serous papillary, uterine cervical and thyroid papillary carcinoma (Figure 4), pulmonary large cell, bronchioloalveolar and hepatocellular carcinoma (Figure 5A–E), apparently in the absence of actual infection. On the other hand, both PaCSs and capsulated (Gram-positive) bacteria were detected inside one case of colon carcinoma (Figure 5F–H). PaCSs were not observed in gastric diffuse, ovarian mucinous and breast ductal cancers. Nuclear areas filled with proteasome-like particles, ultrastructurally and cytochemically indistinguishable from those of PaCS, were also found in one case of parotid cancer (Figure 3F and G).

Bottom Line: Particle lysis and loss of proteasome distinctive immunoreactivities were seen in some tumour cell PaCSs, possibly ending in sequestosomes or autophagic bodies.It is concluded that PaCSs are widely represented in human neoplasms and that both non-infectious and infectious factors activating the ubiquitin-proteasome system are likely to be involved in their origin.PaCS detection might help clarify the role of the ubiquitin-proteasome system in carcinogenesis.

View Article: PubMed Central - PubMed

Affiliation: Department of Human Pathology and Genetics, University of Pavia, Pavia, Italy.

ABSTRACT
A novel cytoplasmic structure has been recently characterized by confocal and electron microscopy in H. pylori-infected human gastric epithelium, as an accumulation of barrel-like proteasome reactive particles colocalized with polyubiquitinated proteins, H. pylori toxins and the NOD1 receptor. This proteasome particle-rich cytoplasmic structure (PaCS), a sort of focal proteasome hyperplasia, was also detected in dysplastic cells and was found to be enriched in SHP2 and ERK proteins, known to play a role in H. pylori-mediated gastric carcinogenesis. However, no information is available on its occurrence in neoplastic growths. In this study, surgical specimens of gastric cancer and various other human epithelial neoplasms have been investigated for PaCSs by light, confocal and electron microscopy including correlative confocal and electron microscopy (CCEM). PaCSs were detected in gastric cohesive, pulmonary large cell and bronchioloalveolar, thyroid papillary, parotid gland, hepatocellular, ovarian serous papillary, uterine cervix and colon adenocarcinomas, as well as in pancreatic serous microcystic adenoma. H. pylori bodies, their virulence factors (VacA, CagA, urease, and outer membrane proteins) and the NOD1 bacterial proteoglycan receptor were selectively concentrated inside gastric cancer PaCSs, but not in PaCSs from other neoplasms which did, however, retain proteasome and polyubiquitinated proteins reactivity. No evidence of actual microbial infection was obtained in most PaCS-positive neoplasms, except for H. pylori in gastric cancer and capsulated bacteria in a colon cancer case. Particle lysis and loss of proteasome distinctive immunoreactivities were seen in some tumour cell PaCSs, possibly ending in sequestosomes or autophagic bodies. It is concluded that PaCSs are widely represented in human neoplasms and that both non-infectious and infectious factors activating the ubiquitin-proteasome system are likely to be involved in their origin. PaCS detection might help clarify the role of the ubiquitin-proteasome system in carcinogenesis.

Show MeSH
Related in: MedlinePlus