Project description:Exposure of humans to bisphenol A (BPA) is widespread and continuous. We previously showed that perinatal exposure to BPA increased prostate cancer risk in adult rats. Yet the effects of protracted, exposure to BPA during adulthood have not been studied. In this study, we subjected Noble rats to 32 weeks of co-treatment with testosterone (T) and BPA (low- or high-dose) or T and 17β-estradiol (E2) via Silastic capsule implants. Circulating T levels were comparable in all treatment groups, whereas the levels of free BPA were elevated in the groups that received T+low BPA (1.06 ± 0.05 ng/ml, P<0.05) and T+high BPA (10.37 ± 0.43 ng/ml, P<0.01) when compared with those in controls (0.1 ± 0.05 ng/ml). T+low/high BPA induced prostatic hyperplasia, low-grade prostatic intraepithelial neoplasia (PIN), and intraepithelial infiltration of T-lymphocytes only in the lateral prostates (LPs), whereas T+E2 induced high-grade PIN in this prostatic lobe. Genome-wide transcriptome analysis identified differential changes in the LPs of T+BPA and T+E2 treatments, with aberrant expression of multiple genes in the regulatory network controlled by the transcription factor hepatic nuclear factor 4α (HNF4α) specifically in BPA- but not E2-treated LPs. These findings suggest that the adult rat prostate is susceptible to transcriptomic reprogramming by BPA associated with the development of prostate pathology in a manner distinct from that of E2. The relevance of these data to the previous report demonstrating an association between high urinary levels of BPA and prostate cancer needs to be studied further.
Project description:Bisphenol A (BPA) is primarily used to make polycarbonate plastic, with a global capacity of production exceeding 8 million tons per year. Biomonitoring studies with human urine, blood and tissue samples suggest that humans are subjected to widespread and continuous exposure to BPA. It has been well established that early life exposure to BPA predisposes the prostate gland to carcinogenesis later in life. However, it remains unknown if BPA exposure during adulthood induces benign or neoplastic pathology in the prostate. The main objective of the present study is to determine the effects of BPA exposures during adulthood on the prostate and to characterize the global transcriptional reprogramming underlying endocrine disruption by BPA. We elevated circulating levels of free BPA in Noble rats to the human-relevant internal dose range with BPA-filled Silastic implants while maintaining the physiological levels of testosterone (T) with T-filled implants. Cotreatment with T and 17β-estradiol (E2) was our reference regimen which induced preneoplastic and cancereous lesions. The T + low/high dose of BPA induced prostatic hyperplasia, low-grade prostate intraepithelial neoplasia (LGPIN) and intraepithelial infiltration of T-lymphocytes specifically in the lateral prostate (LP). Using microarray analysis, we delineated specific impacts of low and high dose of BPA (with the T-support) on the gene expression program in LPs. Hierarchical clustering revealed that the endocrine disrupting effects of T + low dose of BPA showed partial resemblance to those of T + high dose of BPA and T+E2. In contrast, the influence of T+ high dose of BPA on the LP transcriptome was completely different from those of T + E2. Further, IPA analysis of specific T+ low or high BPA gene signature identified a transcription factor, HNF4α, as a regulatory hub affecting a number of differentially expressed genes by BPA exposures. These findings suggest that the adult rat prostate is still venerable to the endocrine disrupting effects of BPA. Perhaps chronic exposure to low dose of BPA provides a niche comprising heightened cell proliferation, inflammatory responses and disrupted gene expression program, which favor the onset and development of prostatic benign or malignant diseases in men. Rat lateral prostates were collected from untreated control and treated groups [Testosterone (T) + Estradiol (E2), T + low dose Bisphenol A (low BPA) and T + high BPA] for RNA extraction and hybridization on Affymetrix microarrays. We sought to identify transcriptional signature of BPA exposures in the lateral prostate gland.
Project description:Gene expression microarray analysis was performed on ventral prostate from normal adult rats, and adult rats treated BPA for 4 weeks(10 animals per group). Animals of 4 groups were treated with bisphenol-A (0,10, 30, or 90 ug/kg, i.g., daily) for 4 weeks, and the dosing volume is 10 ml/kg body weight. In this experiment, we only selected samples from two doses(0 and 10µg/kg) to analyze.
Project description:We generated a novel Six2-Cre+/-PKAcaRfl/wt (CA-PKA) CA-PKA mouse in which expression of constitutive-active PKAcaR was induced in gastric mesenchyme progenitors. CA-PKA mice showed disruption of gastric homeostasis characterized by aberrant mucosal development and epithelial hyperproliferation; ultimately developing multiple features of gastric corpus preneoplasia including decreased parietal cells, mucous cell hyperplasia, spasmolytic peptide expressing metaplasia (SPEM) with intestinal characteristics and dysplastic and invasive cystic glands. Our results show that constitutively active PKAcaR in the stomach mesenchyme nonautonomously disrupts gastric homeostasis characterized by increased epithelial proliferation and aberrant epithelial maldevelopment, ultimately leading to gastric preneoplasia.
Project description:Emerging evidence suggests that estrogen and prolactin (PRL) play a key role in prostate cancer development, yet their relationship and molecular actions in prostate is not well understood. To address this issue, we made the first direct comparison of estrogen and PRL actions in the Noble rat (NBL) prostate dysplasia model.
Project description:Cellular plasticity is a key feature of cancer that enables tumor cells to switch lineage identities, driving disease progression and resistance to therapy. In invasive mucinous adenocarcinoma (IMA), a pronounced pulmonary-to-gastric lineage switch occurs as NKX2.1 is lost and HNF4α, a master regulator of gastric differentiation, is upregulated. Although absent in normal alveolar type 2 cells, HNF4α is aberrantly expressed in most IMA tumors. In this study, we investigate the role of HNF4α within established IMAs and find that it directly activates a gastric differentiation program, particularly in pit cells. Loss of HNF4α disrupts this program and permits FOXA1 and FOXA2 to bind new regulatory sites, leading to the upregulation of neuronal and liver-like gene modules. In light of the poor response of mucinous tumors to KRAS inhibitors, we investigated whether HNF4α modulates sensitivity to KRASG12D targeted therapy. Treatment with MRTX1133 revealed that loss of HNF4α significantly increases IMA sensitivity by reducing the IC50 in vitro and enhancing tumor regression in vivo. Mechanistically, HNF4α deletion impairs cell-cycle progression in drug-tolerant persister cells, while tumors retaining HNF4α maintain these cell-cycle regulators despite KRAS inhibition, promoting persister cell survival. Our findings establish HNF4α as a critical driver of IMA biology governing both gastric differentiation and resistance to KRAS inhibitors and support the development of combination strategies to overcome therapeutic resistance in IMA.
Project description:Cellular plasticity is a key feature of cancer that enables tumor cells to switch lineage identities, driving disease progression and resistance to therapy. In invasive mucinous adenocarcinoma (IMA), a pronounced pulmonary-to-gastric lineage switch occurs as NKX2.1 is lost and HNF4α, a master regulator of gastric differentiation, is upregulated. Although absent in normal alveolar type 2 cells, HNF4α is aberrantly expressed in most IMA tumors. In this study, we investigate the role of HNF4α within established IMAs and find that it directly activates a gastric differentiation program, particularly in pit cells. Loss of HNF4α disrupts this program and permits FOXA1 and FOXA2 to bind new regulatory sites, leading to the upregulation of neuronal and liver-like gene modules. In light of the poor response of mucinous tumors to KRAS inhibitors, we investigated whether HNF4α modulates sensitivity to KRASG12D targeted therapy. Treatment with MRTX1133 revealed that loss of HNF4α significantly increases IMA sensitivity by reducing the IC50 in vitro and enhancing tumor regression in vivo. Mechanistically, HNF4α deletion impairs cell-cycle progression in drug-tolerant persister cells, while tumors retaining HNF4α maintain these cell-cycle regulators despite KRAS inhibition, promoting persister cell survival. Our findings establish HNF4α as a critical driver of IMA biology governing both gastric differentiation and resistance to KRAS inhibitors and support the development of combination strategies to overcome therapeutic resistance in IMA.
Project description:Cellular plasticity is a key feature of cancer that enables tumor cells to switch lineage identities, driving disease progression and resistance to therapy. In invasive mucinous adenocarcinoma (IMA), a pronounced pulmonary-to-gastric lineage switch occurs as NKX2.1 is lost and HNF4α, a master regulator of gastric differentiation, is upregulated. Although absent in normal alveolar type 2 cells, HNF4α is aberrantly expressed in most IMA tumors. In this study, we investigate the role of HNF4α within established IMAs and find that it directly activates a gastric differentiation program, particularly in pit cells. Loss of HNF4α disrupts this program and permits FOXA1 and FOXA2 to bind new regulatory sites, leading to the upregulation of neuronal and liver-like gene modules. In light of the poor response of mucinous tumors to KRAS inhibitors, we investigated whether HNF4α modulates sensitivity to KRASG12D targeted therapy. Treatment with MRTX1133 revealed that loss of HNF4α significantly increases IMA sensitivity by reducing the IC50 in vitro and enhancing tumor regression in vivo. Mechanistically, HNF4α deletion impairs cell-cycle progression in drug-tolerant persister cells, while tumors retaining HNF4α maintain these cell-cycle regulators despite KRAS inhibition, promoting persister cell survival. Our findings establish HNF4α as a critical driver of IMA biology governing both gastric differentiation and resistance to KRAS inhibitors and support the development of combination strategies to overcome therapeutic resistance in IMA.
Project description:Cellular plasticity is a key feature of cancer that enables tumor cells to switch lineage identities, driving disease progression and resistance to therapy. In invasive mucinous adenocarcinoma (IMA), a pronounced pulmonary-to-gastric lineage switch occurs as NKX2.1 is lost and HNF4α, a master regulator of gastric differentiation, is upregulated. Although absent in normal alveolar type 2 cells, HNF4α is aberrantly expressed in most IMA tumors. In this study, we investigate the role of HNF4α within established IMAs and find that it directly activates a gastric differentiation program, particularly in pit cells. Loss of HNF4α disrupts this program and permits FOXA1 and FOXA2 to bind new regulatory sites, leading to the upregulation of neuronal and liver-like gene modules. In light of the poor response of mucinous tumors to KRAS inhibitors, we investigated whether HNF4α modulates sensitivity to KRASG12D targeted therapy. Treatment with MRTX1133 revealed that loss of HNF4α significantly increases IMA sensitivity by reducing the IC50 in vitro and enhancing tumor regression in vivo. Mechanistically, HNF4α deletion impairs cell-cycle progression in drug-tolerant persister cells, while tumors retaining HNF4α maintain these cell-cycle regulators despite KRAS inhibition, promoting persister cell survival. Our findings establish HNF4α as a critical driver of IMA biology governing both gastric differentiation and resistance to KRAS inhibitors and support the development of combination strategies to overcome therapeutic resistance in IMA.
Project description:Hepatocyte Nuclear Factor 4α (HNF4α), master regulator of hepatocyte differentiation, is regulated by two promoters (P1 and P2). P1-HNF4α but not P2-HNF4α is expressed in normal adult liver while both P1- and P2-HNF4α are expressed in fetal liver and liver cancer. To determine the physiological function of the HNF4α isoforms, we compared P2-HNF4α-expressing exon swap mice to wildtype (WT) using RNA-seq, ChIP-seq, proteomics, protein binding microarrays (PBMs) and metabolomics. P2-HNF4α orchestrates a distinct transcriptomic and metabolomic profile.