Prognostic relevance of autophagy-related markers LC3, p62/sequestosome 1, Beclin-1 and ULK1 in colorectal cancer patients with respect to KRAS mutational status

Abstract

BackgroundAutophagy is a cellular pathway that regulates transportation of cytoplasmic macromolecules and organelles to lysosomes for degradation. Autophagy is involved in both tumorigenesis and tumour suppression. Here we investigated the potential prognostic value of the autophagy-related proteins Beclin-1, p62, LC3 and uncoordinated (UNC) 51-like kinase 1 (ULK1) in a cohort of colorectal cancer (CRC) specimens.MethodsIn this study, we analysed the immunoexpression of the autophagy-related proteins p62, LC3, Beclin-1 and ULK1 in 127 CRC patients with known KRAS mutational status and detailed clinical follow-up.ResultsSurvival analysis of p62 staining showed a significant correlation of cytoplasmic (not nuclear) p62 expression with a favourable tumour-specific overall survival (OS). The prognostic power of cytoplasmic p62 was found in the KRAS-mutated subgroup but was lost in the KRAS wildtype subgroup. Survival analysis of Beclin-1 staining did not show an association with OS in the complete cohort. LC3 overexpression demonstrated a slight, though not significant, association with decreased OS. Upon stratifying cases by KRAS mutational status, nuclear (not cytoplasmic) Beclin-1 staining was associated with a significantly decreased OS in the KRAS-mutated subgroup but not in the KRAS wildtype CRCs. In addition, LC3 overexpression was significantly associated with decreased OS in the KRAS-mutated CRC subgroup. ULK1 expression was not correlated to survival.ConclusionsImmunohistochemical analyses of LC3, p62 and Beclin-1 may constitute promising novel prognostic markers in CRC, especially in KRAS-mutated CRCs. This strategy might help in identifying high-risk patients who would benefit from autophagy-related anticancer drugs.Electronic supplementary materialThe online version of this article (doi:10.1186/s12957-016-0946-x) contains supplementary material, which is available to authorized users.

Intranuclear inclusions in hepatocellular carcinoma contain autophagy‐associated proteins and correlate with prolonged survival

“…To clarify if autophagy-associated proteins [14] are detectable in these nuclear inclusions we looked for the presence of the proteins p62/sequestosome1, ubiquitin, LC3B, cathepsin B and cathepsin D by immunohistochemistry. Notably, p62 is also involved in several biological processes [15,16] including NFκB activity, cell proliferation [17,18], apoptosis [19], Keap1-Nrf2 system [20], DNA repair [21,22] and is associated with several cancer types [23][24][25][26][27][28][29][30][31]. In this study we investigated the occurrence of nuclear inclusions in hepatocytes of patients with HCC, characterised the inclusions by means of electron microscopy and immunohistochemistry, and explored if these inclusions have any impact on patient survival.…”

Association of autophagy status with amount of Fusobacterium nucleatum in colorectal cancer

“…We did not observe significant association of tumour BECN1, MAP1LC3, and SQSTM1 expression levels with colorectal cancer mortality. Prognostic roles of tumour BECN1, MAP1LC3, and SQSTM1 in colorectal cancer remain controversial, possibly due to differences in study populations, designs, and methods as well as a multifaceted nature of autophagic process [54][55][56][57][58][59][60][61].…”

“…Autophagy is a complex multistep process where more than 30 autophagy-related genes have been identified to make up the core machinery [16][17][18][19]. Although BECN1, MAP1LC3, and SQSTM1 have been used widely as immunohistochemistry-based autophagy markers in human FFPE tissues [54][55][56][57][58][59][60][61], a simultaneous multimarker evaluation of other components of the autophagic pathway might further enlighten the interactions between autophagy and microbiota. Finally, we used a qPCR assay for F. nucleatum and Bifidobacterium genus in FFPE tissue specimens; therefore, the detection rates might have been influenced by histopathology procedures and storage conditions.…”

Effect of UBE2Q on BECN and CEA Protein in Colorectal Cancer Cells

“…Also, western blot results showed increased UBE2Q1 expression in tumor tissues compared to normal cells [20]. The BECN1 gene was identified as the first autophagy marker in human CRC [21]. Zuli Yang et al (2015) studied Beclin-1 levels in CRC cells and found that Beclin-1 expression was higher in CRC cells than in normal cells [22].…”