Metabolic stress and antipsychotic treatment induced gene expression alterations in human cell

Enterochromaffin-like (ECL) cell hyperplasia and then irreversible neoplasia can be generated in the African rodent Mastomys natalensis using the H2 receptor blocker, loxtidine, for 8–16 wk. We used a GeneChip approach complemented by standard technologies to identify gene expression alterations in the gastric mucosa during gastrin-mediated ECL cell transformation. Gastric mucosa (mucosal scrapping) and ECL cell-enriched fractions were obtained from untreated Mastomys (controls) and from animals treated with loxtidine for 8 wk (hyperplasia). Tumor ECL cells were obtained by hand-dissection of gastric ECL cell nodules from animals treated with loxtidine for >16 wk and from a spontaneously developed ECL cell tumor. RNA was isolated, examined on rat U34A GeneChips, and comparison analysis was performed to identify altered gene expression. Alterations in gene expressions were examined further by immunohistochemistry, quantitative RT-PCR (Q-RT-PCR), sequencing and Western blot. GeneSpring analysis demonstrated alterations in few genes (<20) in hyperplastic and tumor mucosa. The histamine H1 receptor was consistently increased in proliferating mucosa. This gene change was confirmed by Q-RT-PCR. Other genes showing alterations included neural-(chromogranin A and somatostatin), cell-cycle-, and AP-1-associated genes. Immunostaining confirmed alterations in neural markers. Cluster analysis of ECL cell-enriched samples demonstrated that c- fos and junD were differently regulated. Q-RT-PCR and Western blot in prospectively collected gastric mucosal samples confirmed the differential expression of Fos and Jun. The negative regulators of AP-1, JunD, and Menin were decreased in tumor mucosa. A missense of unknown function was noted in the menin gene. Hypergastrinemia in an animal model of gastric carcinoids differentially altered the histamine type 1 receptor and gene expression and protein composition of AP-1. These results suggest that expression of this receptor and an altered composition of AP-1 with a loss of inhibition play a role in ECL cell transformation.

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Human cell transformation by combined lineage conversion and oncogene expression

Oncogene ◽

10.1038/s41388-021-01940-0 ◽

2021 ◽

Author(s):

Biswajyoti Sahu ◽

Päivi Pihlajamaa ◽

Kaiyang Zhang ◽

Kimmo Palin ◽

Saija Ahonen ◽

...

Keyword(s):

Gene Expression ◽

Liver Cancer ◽

Human Cell ◽

Genetic Disease ◽

Cell Transformation ◽

Human Fibroblasts ◽

Driver Mutations ◽

Primary Hepatocytes ◽

Direct Support

AbstractCancer is the most complex genetic disease known, with mutations implicated in more than 250 genes. However, it is still elusive which specific mutations found in human patients lead to tumorigenesis. Here we show that a combination of oncogenes that is characteristic of liver cancer (CTNNB1, TERT, MYC) induces senescence in human fibroblasts and primary hepatocytes. However, reprogramming fibroblasts to a liver progenitor fate, induced hepatocytes (iHeps), makes them sensitive to transformation by the same oncogenes. The transformed iHeps are highly proliferative, tumorigenic in nude mice, and bear gene expression signatures of liver cancer. These results show that tumorigenesis is triggered by a combination of three elements: the set of driver mutations, the cellular lineage, and the state of differentiation of the cells along the lineage. Our results provide direct support for the role of cell identity as a key determinant in transformation and establish a paradigm for studying the dynamic role of oncogenic drivers in human tumorigenesis.

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