The effects of epidermal growth factor on gene expression in human fibroblasts

Plant molecular farming-derived epidermal growth factor revolutionizes hydrogels for improving glandular epithelial organoid biofabrication

Epidermal growth factor (EGF) is a known signaling cue essential towards the development and organoid biofabrication particularly for exocrine glands. This study developed an in vitro EGF delivery platform with Nicotiana benthamiana plant-produced EGF (P-EGF) encapsulated on hyaluronic acid/alginate (HA/Alg) hydrogel to improve the effectiveness of glandular organoid biofabrication in short-term culture systems. Primary submandibular gland epithelial cells were treated with 5 - 20 ng/mL of P-EGF and commercially available bacteria-derived EGF (B-EGF). Cell proliferation and metabolic activity were measured by MTT and luciferase-based ATP assays. P-EGF and B-EGF 5 - 20 ng/mL promoted glandular epithelial cell proliferation during 6 culture days on a comparable fashion. Organoid forming efficiency and cellular viability, ATP-dependent activity and expansion were evaluated using two EGF delivery systems, HA/Alg-based encapsulation and media supplementation. Phosphate buffered saline (PBS) was used as a control vehicle. Epithelial organoids fabricated from PBS-, B-EGF-, and P-EGF-encapsulated hydrogels were characterized genotypically, phenotypically and by functional assays. P-EGF-encapsulated hydrogel enhanced organoid formation efficiency and cellular viability and metabolism relative to P-EGF supplementation. At culture day 3, epithelial organoids developed from P-EGF-encapsulated HA/Alg platform contained functional cell clusters expressing specific glandular epithelial markers such as exocrine pro-acinar (AQP5, NKCC1, CHRM1, CHRM3, Mist1), ductal (K18, Krt19), and myoepithelial (α-SMA, Acta2), and possessed a high mitotic activity (38-62% Ki67 cells) with a large epithelial progenitor population (∼70% K14 cells). The P-EGF encapsulation strikingly upregulated the expression of pro-acinar AQP5 cells through culture time when compared to others (B-EGF, PBS). Thus, the utilization of Nicotiana benthamiana in molecular farming can produce EGF biologicals amenable to encapsulation in HA/Alg-based in vitro platforms, which can effectively and promptly induce the biofabrication of exocrine gland organoids.

Epigenetic targets for melatonin: induction of histone H3 hyperacetylation and gene expression in C17.2 neural stem cells

We have reported the induction of glial cell line-derived neurotrophic factor, a potent survival factor for dopaminergic neurons, in the C17.2 neural stem cell line following in vitro treatment with melatonin. Furthermore, we have detected the melatonin MT(1) receptor in these cells. Given these findings and recent evidence that melatonin may play a role in cellular differentiation, we examined whether this indoleamine induces morphological and transcriptional changes suggestive of a neuronal phenotype in C17.2 cells. Moreover, in order to extend preliminary evidence of a potential role for melatonin in epigenetic modulation, its effects on the mRNA expression of several histone deacetylase (HDAC) isoforms and on histone acetylation were examined. Physiological concentrations of melatonin (nanomolar range) increased neurite-like extensions and induced mRNA expression of the neural stem cell marker, nestin, the early neuronal marker beta-III-tubulin and the orphan nuclear receptor nurr1 in C17.2 cells. The indoleamine also significantly increased mRNA expression for various HDAC isoforms, including HDAC3, HDAC5, and HDAC7. Importantly, treatment with melatonin for 24 hr caused a significant increase in histone H3 acetylation, which is associated with chromatin remodeling and gene transcription. Since the melatonin MT(2) receptor was not detected in C17.2 cells, it is likely that the MT(1) receptor is involved in mediating these physiological effects of melatonin. These findings suggest novel roles for melatonin in stem cell differentiation and epigenetic modulation of gene transcription.

Oncogene coexpression in mesenchymal neoplasia correlates with EGF transcription

Epidermal growth factor (EGF) is a potent mitogenic factor for cells of mesodermal and ectodermal origin, and its over-expression is associated with a variety of cancers. We asked whether oncogene coexpression occurs in mesenchymal neoplasms, if coexpression correlates with EGF transcription, and whether coexpression can be attributed to the EGF-induced overexpression of oncogenes. We quantified the mRNA concentrations of EGF and 14 oncogenes in 42 primary sarcomas, 31 benign tumors, and 10 skeletal muscle controls, and compared mRNA concentrations and gene pair correlations in EGF positive (EGF+) tumors to transcript concentrations and correlations in EGF negative (EGF-) tumors. Transcripts were detected by real time reverse transcription-polymerase chain reaction. Pearson's correlation coefficients identified gene associations, and gene synchrony associated with EGF expression was evaluated using chi square. Transcript concentrations in tumors were compared graphically and with t tests. Gene correlations predominated in EGF+ benign tumors and in EGF- primary sarcomas. The dichotomy in oncogene coexpression evident in benign and malignant tumors could not be attributed to statistical differences in mRNA content between EGF+ and EGF- tumors. EGF may enhance, or may indicate the presence of, oncogene coexpression in benign mesenchymal lesions, but counters gene synchronization in sarcomas.

Gene expression profiling defined pathways correlated with fibroblast cell proliferation induced by Opisthorchis viverrini excretory/secretory product

AIM: To investigate the mechanism of fibroblast cell proliferation stimulated by the Opisthorchis viverrini excretory/secretory (ES) product.

METHODS: NIH-3T3, mouse fibroblast cells were treated with O. viverrini ES product by non-contact co-cultured with the adult parasites. Total RNA from NIH-3T3 treated and untreated with O. viverrini was extracted, reverse transcribed and hybridized with the mouse 15K complementary DNA (cDNA) array. The result was analyzed by ArrayVision version 5 and GeneSpring version 5 softwares. After normalization, the ratios of gene expression of parasite treated to untreated NIH-3T3 cells of 2-and more-fold upregulated was defined as the differentially expressed genes. The expression levels of the signal transduction genes were validated by semi-quantitative SYBR-based real-time RT-PCR.

RESULTS: Among a total of 15 000 genes/ESTs, 239 genes with established cell proliferation-related function were 2 fold-and more-up-regulated by O. viverrini ES product compared to those in cells without exposure to the parasitic product. These genes were classified into groups including energy and metabolism, signal transduction, protein synthesis and translation, matrix and structural protein, transcription control, cell cycle and DNA replication. Moreover, the expressions of serine-threonine kinase receptor, receptor tyrosine kinase and collagen production-related genes were up-regulated by O. viverrini ES product. The expression level of signal transduction genes; pkC, pdgfrα, jak 1, eps 8, tgfβ 1i4, strap and h ras measured by real-time RT-PCR confirmed their expression levels to those obtained from cDNA array. However, only the up-regulated expression of pkC, eps 8 and tgfβ 1i4 which are the downstream signaling molecules of either epidermal growth factor (EGF) or transforming growth factor-β (TGF-β) showed statistical significance (P < 0.05).

CONCLUSION: O. viverrini ES product stimulates the significant changes of gene expression in several functional categories and these mainly include transcripts related to cell proliferation. The TGF-β and EGF signal transduction pathways are indicated as the possible pathways of O. viverrini-driven cell proliferation.

Effects of epidermal growth factor/hydrocortisone on the growth and differentiation of human ovarian surface epithelium

OBJECTIVE

Ovarian surface epithelium (OSE), the precursor of the epithelial ovarian carcinomas, has limited growth potential in culture. Epidermal growth factor+hydrocortisone (EGF+HC) enhances its growth but induces epitheliomesenchymal transition (EMT). This study was undertaken to define the effects of EGF+HC and their reversibility, to optimize growth-promoting media, and to relate OSE phenotypes in vitro to physiologic states in vivo.

METHODS

OSE was cultured in media 199/MDCB105 or EBM (Clonetics) with 2% or 10% fetal bovine serum with or without 10 ng/mL EGF, 1.0 microg/mL HC, and 1.0 microg/mL bovine brain extract. Growth rates and growth potentials (population doublings [PD] to senescence) were defined, and growth patterns and expression of keratin and collagen types III and IV were compared with the ovarian cancer cell lines OVCAR3 and SKOV3.

RESULTS

EGF+HC increased growth potentials from 12-14 PD to 40-42 PD and reduced PD time from 53 hours to 20 hours. Without EGF+HC, OSE cells remained uniformly epithelial. EGF+HC induced EMT (mesenchymal shapes, reduced keratin, and production of collagenous extracellular matrix), but the EMT response varied greatly among OSE from different women. EMT was reversed over 1-2 weeks by subculture into EGF+HC-free medium in passage 1, but inconsistently thereafter. EGF+HC had no effect on the differentiation of ovarian carcinoma lines.

CONCLUSION

The phenotype of intact OSE in vivo is most closely reproduced in media without EGF+HC. EGF+HC enhances growth but initiates EMT, which likely mimics a repair response. Variations in EGF+HC-induced phenotypes point to the existence of OSE subpopulations with differing responsiveness to growth factors or steroids, which may relate to their susceptibility to malignant transformation.

mRNA level of alpha-2-macroglobulin as an aging biomarker of human fibroblasts in culture

Cellular senescence is a well-established model system for studying the molecular basis of aging. To identify a reliable biomarker for cellular age and further study the gene expression of aging, we profiled the gene expression difference between aged and young cultured human embryonic lung fibroblasts by high-density complementary deoxyribonucleic acid (cDNA) arrays. Among the differentially expressed genes, alpha-2-macroglobulin (alpha(2)M) was selected for further study. Its gene expression level as a function of population doubling level (PDL) in cultured fibroblasts was determined by RT-PCR and northern hybridization. mRNA level of alpha(2)M showed a positive linear-correlation with cumulative PDL. Additional assays revealed that the levels of alpha(2)M increased in irreversible growth arrest induced by sublethal H(2)O(2), but not in quiescent state of cultured fibroblasts induced by serum-deprivation, and remained stable in Hela cells. These results suggest that mRNA level of alpha(2)M can be used as a biomarker of aging in cultured fibroblasts. mRNA level of alpha(2)M showed significant difference between newborn and old human leucocytes, which suggest that the mRNA level of alpha(2)M may be used as a biomarker of aging in vivo.