Ubiquitin cytochemical changes during azaserine-initiated pancreatic carcinogenesis

Epigenetic reprogramming in pancreatic premalignancy and clinical implications

Pancreatic cancer (PC) is the most lethal human cancer, with less than 10% 5-year survival. Pancreatic premalignancy is a genetic and epigenomic disease and is linked to PC initiation. Pancreatic premalignant lesions include pancreatic intraepithelial neoplasia (PanIN), intraductal papillary mucinous neoplasm (IPMN), and mucinous cystic neoplasm (MCN), with pancreatic acinar-to-ductal metaplasia (ADM) as the major source of pancreatic premalignant lesions. Emerging evidence reveals that an epigenetic dysregulation is an early event in pancreatic tumorigenesis. The molecular mechanisms of epigenetic inheritance include chromatin remodeling; modifications in histone, DNA, and RNA; non-coding RNA expression; and alternative splicing of RNA. Changes in those epigenetic modifications contribute to the most notable alterations in chromatin structure and promoter accessibility, thus leading to the silence of tumor suppressor genes and/or activation of oncogenes. The expression profiles of various epigenetic molecules provide a promising opportunity for biomarker development for early diagnosis of PC and novel targeted treatment strategies. However, how the alterations in epigenetic regulatory machinery regulate epigenetic reprogramming in pancreatic premalignant lesions and the different stages of their initiation needs further investigation. This review will summarize the current knowledge of epigenetic reprogramming in pancreatic premalignant initiation and progression, and its clinical applications as detection and diagnostic biomarkers and therapeutic targets in PC.

Immunohistochemical expression of MAP1LC3A and MAP1LC3B protein in breast carcinoma tissues

Autophagy is a protein degradation process within the cell and its deregulation has been linked to various diseases and the formation of cancer. One of the important proteins involved in the autophagy process is microtubule-associated protein 1 light chain 3 (MAP1LC3). The aims of this study were to determine the MAP1LC3A and MAP1LC3B protein expression in both normal and cancer breast tissues and to determine the relationship between the expression of these proteins and type of tissues. Immunohistochemistry assessments were carried out on tissue microarrays consisting of breast tissues. MAP1LC3A expression was detected in 52/56 of normal breast tissue cores and 65/67 of breast cancer tissue cores. MAP1LC3B expression was detected in 55/56 of normal breast tissue cores and 67/67 of breast cancer tissue cores. MAP1LC3A and MAP1LC3B protein are expressed in the majority of normal and cancer breast tissues. A large number of MAP1LC3A and MAP1LC3B positive breast cancer tissues cores have high proportion of stained cells (81-100%) as compared with normal breast tissues. However, a significantly higher number of breast cancer tissues were found to express the MAP1LC3A protein with strong immunoreactivity as compared with the normal tissues, suggesting that MAP1LC3A may play a role in breast cancer development.

Characterisation of the progression of azaserine-induced rat pancreatic adenocarcinoma by proliferative cell nuclear antigen, basement membrane laminin and trypsinogen immunohistochemistry

The progression of azaserine-induced rat pancreatic adenocarcinoma (AC) was characterised using quantitative and semiquantitative immunohistochemistry for proliferating cell nuclear antigen (PCNA), basement membrane laminin (BML) and trypsinogen (TG). Samples were taken 5-20 months after initiation. High PCNA-labelling indices (PCNA LIs) were measured 5 months after the induction of atypical acinar cell nodules (AACNs), which decreased later and stagnated until a further decline in the month 10 adenomas. Then a second premalignant proliferative wave was observed (month 13) within the adenoma stage. Later, in month 20 differentiated ACs PCNA LIs fell to the host tissue level but were found highest in the month 20 anaplastic ACs indicating a switch to malignant proliferation. Month 20 invasive ACs showed a number of separate proliferative foci. In early AACNs, BML decreased and remained low till the local maximum in the month 13 adenoma. Invasive ACs did not express BML. Month 5 AACN and differentiated AC were TG deficient but anaplastic AC regained its TG expression. However invasive AC was again TG negative. These results are discussed in combination with our previous data on progressional changes of autophagic capacity and microvessel densities.