These cells express insulin, but lack other key beta cell markers, and are transcriptionally immature, incapable of sensing glucose, and unable to support calcium influx.
No differences were noted in the protein expression of mature beta cell markers such as Pdx1 and NeuroD1 were noted in EndoC-βH1 cells grown in a human microenvironment but cells were however more sensitive to glucose (4.3-fold increase in insulin secretion following glucose challenge compared with a 1.9-fold increase in cells grown in a non-human microenvironment; p = 0.0003).
These include known beta cell markers (Glut2, Pcksk1, Sytl4) and several novel candidate beta cell markers.
Other beta cell markers IAPP and IGRP showed an increase with the differentiation steps.
These consisted of cells that expressed specific beta cell markers that are not normally expressed in ductal cells.
The generation of cells of the pancreatic lineage was assessed by measuring expression levels of the following markers: IAPP, IGRP, insulin I and insulin II (beta cell markers), the transcriptional regulators Nkx 6.1 and PDX-1 (pancreas development markers) and an endocrine marker, PAX 6 using Q-PCR.
This manifested as the unremarkable enrichment of key beta cell markers including Ins2, Ins1, Mafa and others in this study compared to our work (Additional file 4).
Although these cells can differentiate to express some beta cell markers, their role in the pancreas and in other tissues remains to be defined.
In contrast with the beta cell markers, the expression of all the exocrine markers (Amy, Prss1, Cpa1, Ctrb1, Rbpj1 and Ptf1a) was down-regulated, as was the centroacinar marker Hes1.
It has been possible to direct such cells to express some beta cell markers and even some insulin, but there have been no convincing reports that true beta cells have been formed.
