Metallothionein 1G promotes the differentiation of HT-29 human colorectal cancer cells.
Oncol Rep
; 37(5): 2633-2651, 2017 May.
Article
in En
| MEDLINE
| ID: mdl-28393194
ABSTRACT
Metallothioneins (MTs) are a family of low-molecular-weight, cysteine-rich proteins involved in zinc and redox metabolism, that are epigenetically downregulated during colorectal cancer (CRC) progression, but may be re-induced with a variety of agents. Since loss of MT expression is associated with a worse prognosis, in the present study we investigated the effects of overexpression of the most significantly downregulated isoform in CRC, namely MT1G, on the HT-29 cell line. Overexpression of MT1G resulted in xenograft tumors with an aberrant morphology, characterized by an evident increase in mucin-containing cells that were identified as goblet cells under electron microscopy. Immunohistochemical detection of CDX2 and cytokeratin 20 was also increased, as were gobletcell and enterocyte-specific genes by qRT-PCR. Microarray analysis of gene expression confirmed the alteration of several differentiation signaling pathways, including the Notch pathway. Using sodium butyrate and post-confluent growth as inducers of differentiation, we demonstrated that MT1G does indeed play a functional role in promoting goblet over enterocyte differentiation in vitro. Labile zinc is also induced upon differentiation of CRC cells, functionally contributing to enterocyte over goblet differentiation, as revealed using zincspecific chelating agents. Overall, our results uncover a new tumor-suppressor activity of MT1G in promoting the differentiation of at least some CRC tumors, and implicate MTs and zinc signaling as new players in colorectal differentiation. This further contributes to the hypothesis that re-induction of MTs may have therapeutic value by diminishing the aggressiveness of CRC tumors.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Metallothionein
Limits:
Animals
/
Humans
/
Male
Language:
En
Journal:
Oncol Rep
Journal subject:
NEOPLASIAS
Year:
2017
Document type:
Article
Affiliation country:
Argentina