Fuel types and use in late Western Zhou (877 - 771 BCE) industrial contexts in Northwest China.

To date, the types of fuels used in pottery kilns during the Western Zhou Dynasty have not been adequately addressed. Samples from updraft kilns and semi-downdraft kilns at the Fengjing site, the capital in the late Western Zhou period, were selected for analysis. Through phytolith and wood charcoal analysis, various grasses mainly Panicoideae, Pooideae, and Eragrostidoideae, as well as millet, rice, and wheat crops were identified. Additionally, wood primarily from trees of the Quercus, Ulmus, and Liquidambar taxa was found. These findings suggest that different pottery kilns used similar fuels, demonstrating a broad-spectrum rather than specialized fuel utilization during the Zhou period.

Novel PROTAC probes targeting FOSL1 degradation to eliminate head and neck squamous cell carcinoma cancer stem cells.

Previously, we identified that AP-1 transcription factor FOSL1 is required to maintain cancer stem cells (CSCs) in HNSCC, and an AP-1 inhibitor, T-5224, can eliminate HNSCC CSCs. However, its potency is relatively low, and furthermore, whether T-5224 eradicates CSCs through targeting FOSL1 and whether FOSL1 serves as an effective target for eliminating CSCs in HNSCC, require further validation. We first found that T-5224 can bind to FOSL1 directly. As a proof-of-principle, several cereblon (CRBN)-recruiting PROTACs were designed and synthesized using T-5224 as a warhead for more effective of targeting FOSL1. The top compound can potently degrade FOSL1 in HNSCC, thereby effectively eliminating CSCs to suppress HNSCC tumorigenesis, with around 30 to 100-fold improved potency over T-5224. In summary, our study further validates FOSL1 as an effective target for eliminating CSCs in HNSCC and suggests that PROTACs may provide a unique molecular tool for the development of novel molecules for targeting FOSL1.

CYTOR Facilitates Formation of FOSL1 Phase Separation and Super Enhancers to Drive Metastasis of Tumor Budding Cells in Head and Neck Squamous Cell Carcinoma.

Tumor budding (TB) is a small tumor cell cluster with highly aggressive behavior located ahead of the invasive tumor front. However, the molecular and biological characteristics of TB and the regulatory mechanisms governing TB phenotypes remain unclear. This study reveals that TB exhibits a particular dynamic gene signature with stemness and partial epithelial-mesenchymal transition (p-EMT). Importantly, nuclear expression of CYTOR is identified to be the key regulator governing stemness and the p-EMT phenotype of TB cells, and targeting CYTOR significantly inhibits TB formation, tumor growth and lymph node metastasis in head and neck squamous cell carcinoma (HNSCC). Mechanistically, CYTOR promotes tumorigenicity and metastasis of TB cells by facilitating the formation of FOSL1 phase-separated condensates to establish FOSL1-dependent super enhancers (SEs). Depletion of CYTOR leads to the disruption of FOSL1-dependent SEs, which results in the inactivation of cancer stemness and pro-metastatic genes. In turn, activation of FOSL1 promotes the transcription of CYTOR. These findings indicate that CYTOR is a super-lncRNA that controls the stemness and metastasis of TB cells through facilitating the formation of FOSL1 phase separation and SEs, which may be an attractive target for therapeutic interventions in HNSCC.

BET inhibition triggers antitumor immunity by enhancing MHC class I expression in head and neck squamous cell carcinoma.

BET inhibition has been shown to have a promising antitumor effect in multiple tumors. However, the impact of BET inhibition on antitumor immunity was still not well documented in HNSCC. In this study, we aim to assess the functional role of BET inhibition in antitumor immunity and clarify its mechanism. We show that BRD4 is highly expressed in HNSCC and inversely correlated with the infiltration of CD8+ T cells. BET inhibition potentiates CD8+ T cell-based antitumor immunity in vitro and in vivo. Mechanistically, BRD4 acts as a transcriptional suppressor and represses the expression of MHC class I molecules by recruiting G9a. Pharmacological inhibition or genetic depletion of BRD4 potently increases the expression of MHC class I molecules in the absence and presence of IFN-γ. Moreover, compared to PD-1 blocking antibody treatment or JQ1 treatment individually, the combination of BET inhibition with anti-PD-1 antibody treatment significantly enhances the antitumor response in HNSCC. Taken together, our data unveil a novel mechanism by which BET inhibition potentiates antitumor immunity via promoting the expression of MHC class I molecules and provides a rationale for the combination of ICBs with BET inhibitors for HNSCC treatment.

Exploration of naphthoquinone analogs in targeting the TCF-DNA interaction to inhibit the Wnt/ß-catenin signaling pathway.

The Wnt/ß-catenin signaling pathway plays extensive roles in cancer initiation, proliferation, and development, and has been implicated in the regulation of stem cells in the intestinal crypt, widely accepted as responsible for colorectal cancer (CRC) origination. This pathway has been a target of interest for many years for chemotherapeutic development of CRC due to its implication in most cases. Previously, a series of naphthoquinone analogs have been identified to inhibit the Wnt/ß-catenin. It was postulated that these compounds exhibit their inhibitory activity via binding to ß-catenin at the ß-catenin/TCF4 interaction interface. In this study, we aimed to further define the critical pharmacophore for these compounds and verify their mechanisms of action for their abilities to inhibit the Wnt/ß-catenin signaling pathway. Interestingly, our data suggested two of the compounds, compounds 3 and 6, may potently inhibit the Wnt/ß-catenin signaling pathway via inhibition of the TCF4/DNA interaction, a novel finding compared to previous studies on these compounds. Our computational studies suggested that the compounds bound within the DNA binding HMG-box domain of TCF4 to elicit their inhibitory action. These compounds inhibited Wnt signaling in a dose dependent manner, suppressed Wnt direct target genes and demonstrated unforeseen degradation of the TCF4 protein. Thus, this study revealed a potentially novel mechanism of action of the chloro-naphthoquinone as possibly a multi-targeting scaffold, which warrants further investigation in future drug discovery on the 'undruggable" TCF proteins and an aberrantly activated Wnt/ß-catenin signaling pathway.

FGFR1 Overexpression Induces Cancer Cell Stemness and Enhanced Akt/Erk-ER Signaling to Promote Palbociclib Resistance in Luminal A Breast Cancer Cells.

Resistance to CDK4/6 inhibitors (CDKis) is emerging as a clinical challenge. Identification of the factors contributing to CDKi resistance, with mechanistic insight, is of pivotal significance. Recent studies linked aberrant FGFR signaling to CDKi resistance. However, detailed mechanisms are less clear. Based on control and FGFR1 overexpressing luminal A cell line models, we demonstrated that FGFR1 overexpression rendered the cells resistant to palbociclib. FGFR1 overexpression abolished palbociclib-mediated cell cycle arrest, as well as the attenuated palbociclib-induced inhibition of G1/S transition regulators (pRb, E2F1, and cyclin D3) and factors that promote G2/M transition (cyclin B1, cdc2/CDK1, and cdc25). Importantly, FGFR1-induced palbociclib resistance was associated with promotion of cancer cell stemness and the upregulation of Wnt/ß-catenin signaling. We found that palbociclib may function as an ER agonist in MCF-7/FGFR1 cells. Upregulation of the ER-mediated transcription in MCF-7/FGFR1 cells was associated with ERα phosphorylation and enhanced receptor tyrosine kinase signaling. The combination of palbociclib with FGFR-targeting AZD4547 resulted in remarkable synergistic effects on MCF-7/FGFR1 cells, especially for the inhibition of cancer cell stemness. Our findings of FGFR1-induced palbociclib resistance, promotion of cancer stem cells and associated molecular changes advance our mechanistic understanding of CDKi resistance, which will facilitate the development of strategies targeting CDKi resistance in breast cancer treatment.

Transcriptional super-enhancers control cancer stemness and metastasis genes in squamous cell carcinoma.

Cancer stem cells (CSCs) play a critical role in invasive growth and metastasis of human head and neck squamous cell carcinoma (HNSCC). Although significant progress has been made in understanding the self-renewal and pro-tumorigenic potentials of CSCs, a key challenge remains on how to eliminate CSCs and halt metastasis effectively. Here we show that super-enhancers (SEs) play a critical role in the transcription of cancer stemness genes as well as pro-metastatic genes, thereby controlling their tumorigenic potential and metastasis. Mechanistically, we find that bromodomain-containing protein 4 (BRD4) recruits Mediators and NF-κB p65 to form SEs at cancer stemness genes such as TP63, MET and FOSL1, in addition to oncogenic transcripts. In vivo lineage tracing reveals that disrupting SEs by BET inhibitors potently inhibited CSC self-renewal and eliminated CSCs in addition to elimination of proliferating non-stem tumor cells in a mouse model of HNSCC. Moreover, disrupting SEs also inhibits the invasive growth and lymph node metastasis of human CSCs isolated from human HNSCC. Taken together, our results suggest that targeting SEs may serve as an effective therapy for HNSCC by eliminating CSCs.

A Super-Enhancer Driven by FOSL1 Controls miR-21-5p Expression in Head and Neck Squamous Cell Carcinoma.

MiR-21-5p is one of the most common oncogenic miRNAs that is upregulated in many solid cancers by inhibiting its target genes at the posttranscriptional level. However, the upstream regulatory mechanisms of miR-21-5p are still not well documented in cancers. Here, we identify a super-enhancer associated with the MIR21 gene (MIR21-SE) by analyzing the MIR21 genomic regulatory landscape in head and neck squamous cell carcinoma (HNSCC). We show that the MIR21-SE regulates miR-21-5p expression in different HNSCC cell lines and disruption of MIR21-SE inhibits miR-21-5p expression. We also identified that a key transcription factor, FOSL1 directly controls miR-21-5p expression by interacting with the MIR21-SE in HNSCC. Moreover, functional studies indicate that restoration of miR-21-5p partially abrogates FOSL1 depletion-mediated inhibition of cell proliferation and invasion. Clinical studies confirmed that miR-21-5p expression is positively correlated with FOSL1 expression. These findings suggest that FOSL1-SE drives miR-21-5p expression to promote malignant progression of HNSCC.

FOSL1 promotes metastasis of head and neck squamous cell carcinoma through super-enhancer-driven transcription program.

Previously, we discovered that FOSL1 facilitates the metastasis of head and neck squamous cell carcinoma (HNSCC) cancer stem cells in a spontaneous mouse model. However, the molecular mechanisms remained unclear. Here, we demonstrated that FOSL1 serves as the dominant activating protein 1 (AP1) family member and is significantly upregulated in HNSCC tumor tissues and correlated with metastasis of HNSCC. Mechanistically, FOSL1 exerts its function in promoting tumorigenicity and metastasis predominantly via selective association with Mediators to establish super-enhancers (SEs) at a cohort of cancer stemness and pro-metastatic genes, such as SNAI2 and FOSL1 itself. Depletion of FOSL1 led to disruption of SEs and expression inhibition of these key oncogenes, which resulted in the suppression of tumor initiation and metastasis. We also revealed that the abundance of FOSL1 is positively associated with the abundance of SNAI2 in HNSCC and the high expression levels of FOSL1 and SNAI2 are associated with short overall disease-free survival. Finally, the administration of the FOSL1 inhibitor SR11302 significantly suppressed tumor growth and lymph node metastasis of HNSCC in a patient-derived xenograft model. These findings indicate that FOSL1 is a master regulator that promotes the metastasis of HNSCC through a SE-driven transcription program that may represent an attractive target for therapeutic interventions.

FGFR1 overexpression renders breast cancer cells resistant to metformin through activation of IRS1/ERK signaling.

Metformin has been suggested as an anti-cancer agent. However, increasing reports show that some tumors are resistant to metformin. Identification of factors affecting metformin mediated cancer therapy is of great significance. FGFR1 is a receptor-tyrosine-kinase that is frequently overexpressed in breast cancer, which is associated with poor-prognosis. To investigate the effect of FGFR1 overexpression on metformin-induced inhibition of breast cancer cells, we demonstrated that FGFR1 overexpression rendered MCF-7 and T47D cells resistant to metformin. In particular, we found that, in addition to AKT and ERK1/2 activation, FGFR1-induced activation of IRS1 and IGF1R, key regulators connecting metabolism and cancer, was associated with metformin resistance. Targeting IRS with IRS1 KO or IRS inhibitor NT157 significantly sensitized FGFR1 overexpressing cells to metformin. Combination of NT157 with metformin induced enhanced inhibition of p-IGF1R, p-ERK1/2 and p-mTOR. Moreover, we demonstrated that IRS1 functions as a critical mediator of the crosstalk between FGFR1 and IGF1R pathways, which involves a feedback loop between IRS1 and MAPK/ERK. Our study highlights the significance of FGFR1 status and IRS1 activation in metformin-resistance, which will facilitate the development of strategies targeting FGFR overexpression-associated metformin resistance.

In Utero Exposure to Bisphenol a Promotes Mammary Tumor Risk in MMTV-Erbb2 Transgenic Mice Through the Induction of ER-erbB2 Crosstalk.

Bisphenol A (BPA) is the most common environmental endocrine disrupting chemical. Studies suggest a link between perinatal BPA exposure and increased breast cancer risk, but the underlying mechanisms remain unclear. This study aims to investigate the effects of in utero BPA exposure on mammary tumorigenesis in MMTV-erbB2 transgenic mice. Pregnant mice were subcutaneously injected with BPA (0, 50, 500 ng/kg and 250 µg/kg BW) daily between gestational days 11-19. Female offspring were examined for mammary tumorigenesis, puberty onset, mammary morphogenesis, and signaling in ER and erbB2 pathways. In utero exposure to low dose BPA (500 ng/kg) induced mammary tumorigenesis, earlier puberty onset, increased terminal end buds, and prolonged estrus phase, which was accompanied by proliferative mammary morphogenesis. CD24/49f-based FACS analysis showed that in utero exposure to 500 ng/kg BPA induced expansion of luminal and basal/myoepithelial cell subpopulations at PND 35. Molecular analysis of mammary tissues at PND 70 showed that in utero exposure to low doses of BPA induced upregulation of ERα, p-ERα, cyclin D1, and c-myc, concurrent activation of erbB2, EGFR, erbB-3, Erk1/2, and Akt, and upregulation of growth factors/ligands. Our results demonstrate that in utero exposure to low dose BPA promotes mammary tumorigenesis in MMTV-erbB2 mice through induction of ER-erbB2 crosstalk and mammary epithelial reprogramming, which advance our understanding of the mechanism associated with in utero exposure to BPA-induced breast cancer risk. The studies also support using MMTV-erbB2 mouse model for relevant studies.

GASC1-Adapted Neoadjuvant Chemotherapy for Resectable Esophageal Squamous Cell Carcinoma: A Prospective Clinical Biomarker Trial.

Neoadjuvant chemotherapy (NCT) is a standard care for esophageal squamous cell carcinoma (ESCC), but the efficacy is unsatisfactory. Cancer stem cells (CSCs) play key roles in chemotherapy resistance. Gene amplified in squamous cell carcinoma 1 (GASC1) is a neoteric gene in stemness maintaining of ESCC. We aimed to reveal whether GASC1 could be a predictive biomarker for NCT in ESCC. ESCC patients (T2-4N0-2M0) were evaluated for GASC1 expression using immunohistochemical staining and classified as GASC1-low group (GLG) and GASC1-high group (GHG). NCT was delivered in two cycles and then the surgery was completed. Primary endpoints were tumor regression grade (TRG) and objective response rate (ORR); secondary endpoints were radical surgical resection (R0) rate and three-year overall survival (OS). 60 patients were eligible with evaluable outcomes: 24 in GHG and 36 in GLG. Between GHG and GLG, TRG1, TRG2, TRG3, and TRG4 were 0 : 16.7%, 20.8% : 41.7%, 58.3% : 36.1%, and 20.8% : 5.6%, respectively (P=0.006); ORR and R0 rate were 33.3% : 69.4% (P=0.006) and 75% : 94.4% (P=0.046), respectively; the median OS was 20 : 32 (months) (P=0.0356). No significant difference in the three-year OS was observed between GHG and GLG: 29.2% : 41.7% (P=0.24). Furthermore, the GASC1 expression level was associated with poor OS independent of other factors by univariate and multivariate analyses. Therefore, GASC1 might be a potential biomarker to predict NCT efficacy for ESCC.

Correlations of Moesin expression with the pathological stage, nerve infiltration, tumor location and pain severity in patients with pancreatic cancer.

PURPOSE: The study aimed to investigate the correlations of the expression of membrane-organizing extension spike protein (moesin) with the pathological stage, nerve infiltration, tumor location and pain severity in patients with pancreatic cancer (PC) and analyze its possible mechanism. METHODS: A total of 43 patients with pancreatic cancer receiving surgical resection in our hospital were enrolled, with the adjacent tissues as controls. Then, quantitative polymerase chain reaction (qPCR) and Western blotting were carried out to measure the expression level of the moesin messenger ribonucleic acid (mRNA) in PC tissues. The expression levels of matrix metalloproteinase-7 (MMP-7), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and IL-10 (IL-10) in PC tissues were detected using enzyme-linked immunosorbent assay (ELISA) kit. The relationship between moesin and the pathological stage of patients was analyzed, followed by further analyses on the correlations of moesin with nerve infiltration, tumor location and pain severity of patients with PC. RESULTS: The results of qPCR and Western blotting demonstrated that the expression levels of the moesin mRNA and moesin in PC tissues were evidently higher than those in adjacent tissues (p<0.01). Based on ELISA, the expression levels of MMP-7, TNF-α and IL-6 (p<0.01) were significantly higher, while the expression level of IL-10 (p<0.01) was obviously lower in PC tissues compared with those in adjacent tissues. The expression of moesin was closely associated with the pathological stage of patients with PC (p<0.01). The expression level of moesin in PC tissues in patients with nerve infiltration was significantly higher than that of those without nerve infiltration (p<0.01). It was distinctly elevated in PC tissues of patients with tumors located in the tail of the pancreas in comparison with those with tumors located in the head of the pancreas (p<0.01). The pain severity was correlated with the expression level of moesin in PC tissues (p<0.01). CONCLUSION: Moesin affects the progression of PC by activating MMP-7 and further promoting the release of TNF-α and IL-6 and decreasing the level of IL-10. The expression of moesin in PC tissues has close relations with the pathological stage of the disease, nerve infiltration, tumor location and pain severity.

Bisphenol AF promotes estrogen receptor-positive breast cancer cell proliferation through amphiregulin-mediated crosstalk with receptor tyrosine kinase signaling.

Exposure to bisphenol A (BPA), an endocrine-disrupting compound, is associated with increased risk of estrogen-related diseases, including estrogen receptor-positive (ER+) breast cancer. Although bisphenol analogs, i.e. bisphenol AF (BPAF), have replaced BPA in industrial settings, increasing data indicate that these alternatives may have similar or even more potent estrogenic effects. As such, BPAF exhibits increased ER binding affinities than BPA in biochemical assays. However, preclinical studies exploring the effects of BPAF on ER+ breast cancer are missing mechanistic data. Thus, we aimed to characterize the effects of BPAF on MCF-7 and T47D ER+ breast cancer cells with mechanistic insight. We found that BPAF promoted cell growth and cell cycle progression concurrently with BPAF-induced ERα transcriptional activity and ER-RTK signaling activation. ER signaling blockage revealed that BPAF-induced cell proliferation and ER-RTK crosstalk were ER-dependent. Gene expression data demonstrated that AREG is a sensitive target of BPAF in our in vitro models. Importantly, we determined that AREG upregulation is necessary for BPAF-induced cellular responses. Ultimately, our novel finding that AREG mediates BPAF-induced ER-RTK crosstalk in ER+ breast cancer cells supports future studies to characterize the impact of BPAF on human ER+ breast cancer risk and to assess the safety profile of BPAF.

Effect of perioperative administration of dexmedetomidine on delirium after cardiac surgery in elderly patients: a double-blinded, multi-center, randomized study.

OBJECTIVE: Postoperative delirium (POD) is a serious complication in elderly patients undergoing cardiac surgery. This study was aimed at investigating the effect of perioperative administration of dexmedetomidine for general anesthesia maintenance on occurrence and duration of POD in elderly patients after cardiac surgery. METHODS: One hundred and sixty-four patients were enrolled after cardiac surgery between June 2009 and December 2016. Patients were assigned by a computer-generated randomization sequence in a 1:1 ratio to receive dexmedetomidine general anesthesia maintenance or propofol general anesthesia maintenance. POD was assessed every day with confusion assessment method for intensive care units (ICU) during the first 5 postoperative days. RESULTS: There was no significance in incidence of POD between the dexmedetomidine group and the propofol group (P=0.0758). In patients treated with dexmedetomidine, the median onset time of delirium was delayed (second day vs first day) and the duration of delirium reduced (2 days vs 3 days) when compared with propofol-treated patients. The dexmedetomidine-treated patients also displayed a lower VAS score and less opiate analgesic consumption. No difference was observed in respect to other postoperative outcomes. CONCLUSION: For elderly patients, perioperative administration of dexmedetomidine reduced incidence, delayed onset and shortened duration of POD after cardiac surgery.

Morphological changes in starch grains after dehusking and grinding with stone tools.

Research on the manufacture, use, and use-wear of grinding stones (including slabs and mullers) can provide a wealth of information on ancient subsistence strategy and plant food utilization. Ancient residues extracted from stone tools frequently exhibit damage from processing methods, and modern experiments can replicate these morphological changes so that they can be better understood. Here, experiments have been undertaken to dehusk and grind grass grain using stone artifacts. To replicate ancient activities in northern China, we used modern stone tools to dehusk and grind twelve cultivars of foxtail millet (Setaria italica), two cultivars of broomcorn millet (Panicum miliaceum) and three varieties of green bristlegrass (Setaira viridis). The residues from both used and unused facets of the stone tools were then extracted, and the starch grains studied for morphological features and changes from the native states. The results show that (1) Dehusking did not significantly change the size and morphology of millet starch grains; (2) After grinding, the size of millet starch grains increases up to 1.2 times larger than native grains, and a quarter of the ground millet starch grains bore surface damage and also exhibited distortion of the extinction cross. This indicator will be of significance in improving the application of starch grains to research in the functional inference of grinding stone tools, but we are unable to yet distinguish dehusked forms from native.

Multiple indicators of rice remains and the process of rice domestication: A case study in the lower Yangtze River region, China.

The process of rice domestication has been studied for decades based on changing morphological characteristics in assemblages of both macroremains, such as charred seeds and spikelet bases, and microremains, such as phytoliths, esp. bulliform and double-peaked phytoliths. The applicability of these indicators in determining if a specific assemblage is wild or domesticated, however, is rarely discussed. To understand the significance of these indicators in the determination of domestication, we collected 38 archaeological samples from eight Neolithic sites, dating from 10-2ka BP, in the lower Yangtze River region to analyze and compare the changes of these different indicators over eight thousand years. The data demonstrate that the comprehensive analysis of multiple indicators may be the best method to study the process of rice domestication developed thus far. An assemblage of rice remains can be identified as domesticated forms if they meet the following criteria simultaneously: 1) the proportion of domesticated-type bulliform phytoliths is more than 73%; and 2) the proportion of domesticated-type rice spikelet bases is higher than 75%. Furthermore, we found that each indicator tends to change steadily and gradually over time, and each stabilized at a different time, suggesting that the characteristics of domesticated rice developed slowly and successively. Changes of multiple indicators during the period between 10,000-2,000 yr BP indicate that the process of rice domestication in the lower Yangtze River region lasted as long as ca. 6,000 years during the Neolithic, and can be divided into three stages with the turning points in the middle Hemudu-late Majiabang culture (6,500-5,800yr BP) and the late Liangzhu culture (4,600-4,300yr BP).

Caloric restriction inhibits mammary tumorigenesis in MMTV-ErbB2 transgenic mice through the suppression of ER and ErbB2 pathways and inhibition of epithelial cell stemness in premalignant mammary tissues.

Caloric intake influences the onset of many diseases, including cancer. In particular, caloric restriction (CR) has been reported to suppress mammary tumorigenesis in various models. However, the underlying cancer preventive mechanisms have not been fully explored. To this end, we aimed to characterize the anticancer mechanisms of CR using MMTV-ErbB2 transgenic mice, a well-established spontaneous ErbB2-overexpressing mammary tumor model, by focusing on cellular and molecular changes in premalignant tissues. In MMTV-ErbB2 mice with 30% CR beginning at 8 weeks of age, mammary tumor development was dramatically inhibited, as exhibited by reduced tumor incidence and increased tumor latency. Morphogenic mammary gland analyses in 15- and 20-week-old mice indicated that CR significantly decreased mammary epithelial cell (MEC) density and proliferative index. To understand the underlying mechanisms, we analyzed the effects of CR on mammary stem/progenitor cells. Results from fluorescence-activated cell sorting analyses showed that CR modified mammary tissue hierarchy dynamics, as evidenced by decreased luminal cells (CD24highCD49flow), putative mammary reconstituting unit subpopulation (CD24highCD49fhigh) and luminal progenitor cells (CD61highCD49fhigh). Mammosphere and colony-forming cell assays demonstrated that CR significantly inhibited mammary stem cell self-renewal and progenitor cell numbers. Molecular analyses indicated that CR concurrently inhibited estrogen receptor (ER) and ErbB2 signaling. These molecular changes were accompanied by decreased mRNA levels of ER-targeted genes and epidermal growth factor receptor/ErbB2 family members and ligands, suggesting ER-ErbB2 signaling cross-talk. Collectively, our data demonstrate that CR significantly impacts ER and ErbB2 signaling, which induces profound changes in MEC reprogramming, and mammary stem/progenitor cell inhibition is a critical mechanism of CR-mediated breast cancer prevention.

DMBA promotes ErbB2­mediated carcinogenesis via ErbB2 and estrogen receptor pathway activation and genomic instability.

Environmental factors, including 7,12­dimethylbenz[a]anthracene (DMBA) exposure, and genetic predisposition, including ErbB2 overexpression/amplification, have been demonstrated to increase breast cancer susceptibility. Although DMBA­ and ErbB2­mediated breast cancers are well­studied in their respective models, key interactions between environmental and genetic factors on breast cancer risk remain unclear. Therefore, the present study aimed to investigate the effect of DMBA exposure on ErbB2­mediated mammary tumorigenesis. MMTV­ErbB2 transgenic mice exposed to DMBA (1 mg) via weekly oral gavage for 6 weeks exhibited significantly enhanced mammary tumor development, as indicated by reduced tumor latency and increased tumor multiplicity compared with control mice. Whole mount analysis of premalignant mammary tissues from 15­week­old mice revealed increased ductal elongation and proliferative index in DMBA­exposed mice. Molecular analyses of premalignant mammary tissues further indicated that DMBA exposure enhanced epidermal growth factor receptor (EGFR)/ErbB2 and estrogen receptor (ER) signaling, which was associated with increased mRNA levels of EGFR/ErbB2 family members and ER­targeted genes. Furthermore, analysis of tumor karyotypes revealed that DMBA­exposed tumors displayed more chromosomal alterations compared with control tumors, implicating DMBA­induced chromosomal instability in tumor promotion in this model. Together, the data suggested that DMBA­induced deregulation of EGFR/ErbB2­ER pathways plays a critical role in the enhanced chromosomal instability and promotion of ErbB2­mediated mammary tumorigenesis. The study highlighted gene­environment interactions that may increase risk of breast cancer, which is a critical clinical issue.