Endogenous IGFBP-3 Mediates Intrinsic Apoptosis Through Modulation of Nur77 Phosphorylation and Nuclear Export

Association Study of IGF-1 rs35767 and rs6214 Gene Polymorphisms with Cancer Susceptibility and Circulating Levels of IGF-1, IGFBP-2, and IGFBP-3 in Colorectal Cancer Patients

Early detection of colorectal cancer (CRC) increases the 5-year survival rate by 90%; therefore, non-invasive biomarkers such as measurable circulating proteins for early detection and prognosis are crucial. Insulin-like growth factor-1 (IGF-1) is involved in the regulation of cell proliferation and apoptosis. IGF binding proteins (IGFBPs) bind and inhibit the activity of IGF-1. It was inconsistently reported that high IGF-1 and IGFBP-2 and low IGFBP-3 circulating levels are associated with high cancer risk, poor prognosis, and tumor metastasis in several cancers. A total of 175 patients with CRC and 429 controls were enrolled in this study. We genotyped for IGF-1 rs35767 and rs6214 gene polymorphisms and assessed their association with circulating levels of IGF-1 and/or the risk for CRC. We also determined plasma levels of IGF-1, IGFBP-2, and IGFBP-3. Neither rs35767 nor rs2614 were associated with cancer risk or IGF-1 levels in our study cohort. IGF-1 and IGFBP-3 levels were higher in controls than in patients, whereas IGFBP-2 was higher in patients than in controls. Only IGFBP-2 was associated with increased tumor grade but not stage. Therefore, IGF-1, IGFBP-2, and IGFBP-3 may be useful as early detection and prognostic biomarkers in CRC.

Signaling Pathways of the Insulin-like Growth Factor Binding Proteins

The 6 high-affinity insulin-like growth factor binding proteins (IGFBPs) are multifunctional proteins that modulate cell signaling through multiple pathways. Their canonical function at the cellular level is to impede access of insulin-like growth factor (IGF)-1 and IGF-2 to their principal receptor IGF1R, but IGFBPs can also inhibit, or sometimes enhance, IGF1R signaling either through their own post-translational modifications, such as phosphorylation or limited proteolysis, or by their interactions with other regulatory proteins. Beyond the regulation of IGF1R activity, IGFBPs have been shown to modulate cell survival, migration, metabolism, and other functions through mechanisms that do not appear to involve the IGF-IGF1R system. This is achieved by interacting directly or functionally with integrins, transforming growth factor β family receptors, and other cell-surface proteins as well as intracellular ligands that are intermediates in a wide range of pathways. Within the nucleus, IGFBPs can regulate the diverse range of functions of class II nuclear hormone receptors and have roles in both cell senescence and DNA damage repair by the nonhomologous end-joining pathway, thus potentially modifying the efficacy of certain cancer therapeutics. They also modulate some immune functions and may have a role in autoimmune conditions such as rheumatoid arthritis. IGFBPs have been proposed as attractive therapeutic targets, but their ubiquity in the circulation and at the cellular level raises many challenges. By understanding the diversity of regulatory pathways with which IGFBPs interact, there may still be therapeutic opportunities based on modulation of IGFBP-dependent signaling.

Insulin-like Growth Factor Binding Protein 3 Increases Mouse Preimplantation Embryo Cleavage Rate by Activation of IGF1R and EGFR Independent of IGF1 Signalling

The viability of embryos cultured in vitro is poor compared to those that develop in vivo. The lack of maternally derived growth factors in vitro may contribute to this problem. Insulin-like growth factor binding protein 3 (IGFBP3) is one such growth factor that has been identified in the maternal reproductive system. This study examined the role of autocrine and exogenous IGFBP3 in mouse preimplantation embryos. Embryos expressed IGFBP3 across all stages of preimplantation development, and addition of exogenous IGFBP3 to embryo culture media increased the rate of development to the 2-, 4-, 5-, and 8-cell stages. Addition of inhibitors of the IGF1 and EGF receptors prevented this IGFBP3-mediated improvement in developmental rate, but the effect was not cumulative, indicating that both receptors are transactivated downstream of IGFBP3 as part of the same signalling pathway. Acute exposure to IGFBP3 increased phosphorylation of Akt and rps6 in 4-8 cell embryos, suggesting activation of the PI3-kinase/Akt pathway downstream of the IGF1 and EGFR receptors to promote cell proliferation and survival. In conclusion, addition of IGFBP3 to embryo culture media increases early cleavage rates independent of IGF1 signalling and therefore, IGFBP3 addition to IVF culture media should be considered.

Upregulated IGFBP3 with Aging Is Involved in Modulating Apoptosis, Oxidative Stress, and Fibrosis: A Target of Age-Related Erectile Dysfunction

Aging has been deemed the primary factor in erectile dysfunction (ED). Herein, age-related changes in the erectile response and histomorphology were detected, and the relationship between aging and ED was investigated based on gene expression levels. Thirty male Sprague–Dawley (SD) rats were randomly divided into 6 groups, and intracavernous pressure (ICP) and mean arterial pressure (MAP) were measured. Subsequently, the corpus cavernosum (CC) was harvested and prepared for histological examinations of apoptosis, oxidative stress (OS), and fibrosis. Then, the microarray dataset (GSE10804) was analyzed to identify differentially expressed genes (DEGs) in ED progression, and hub genes were selected. In addition, aged CC smooth muscle cells (CCSMCs) were isolated to evaluate the function of the hub gene by siRNA interference, qRT–PCR, immunofluorescence staining, enzyme-linked immunosorbent assay, western blot analysis, CCK-8 assay, EdU staining, and flow cytometry approaches. The ICP/MAP and smooth muscle cell (SMC)/collagen ratios declined with aging, while apoptosis and OS levels increased with aging. The enriched functions and pathways of the DEGs were investigated, and 15 hub genes were identified, among which IGFBP3 was significantly upregulated. The IGFBP3 upregulation was verified in the CC of aging rats. Furthermore, aged CCSMCs were transfected with siRNA to knock down IGFBP3 expression. The viability and proliferation of the CCSMCs increased, while apoptosis, OS, and fibrosis decreased. Our findings demonstrate that the erectile response of SD rats declines in parallel with enhanced CC apoptosis, OS, and fibrosis with aging. Upregulation of IGFBP3 plays an important role; furthermore, downregulation of IGFBP3 improves the viability and proliferation of CCSMCs and alleviates apoptosis, OS, and fibrosis. Thus, IGFBP3 is a potential therapeutic target for age-related ED.

Insulin-Like Growth Factor Binding Protein-3 (IGFBP-3): Unraveling the Role in Mediating IGF-Independent Effects Within the Cell

Insulin-like growth factor (IGF) binding protein-3 (IGFBP-3), one of the six members of the IGFBP family, is a key protein in the IGF pathway. IGFBP-3 can function in an IGF-dependent as well as in an IGF-independent manner. The IGF-dependent roles of IGFBP-3 include its endocrine role in the delivery of IGFs from the site of synthesis to the target cells that possess IGF receptors and the activation of associated downstream signaling. IGF-independent role of IGFBP-3 include its interactions with the proteins of the extracellular matrix and the proteins of the plasma membrane, its translocation through the plasma membrane into the cytoplasm and into the nucleus. The C-terminal domain of IGFBP-3 has the ability to undergo cell penetration therefore, generating a short 8-22-mer C-terminal domain peptides that can be conjugated to drugs or genes for effective intracellular delivery. This has opened doors for biotechnological applications of the molecule in molecular medicine. The aim of this this review is to summarize the complex roles of IGFBP-3 within the cell, including its mechanisms of cellular uptake and its translocation into the nucleus, various molecules with which it is capable of interacting, and its ability to regulate IGF-independent cell growth, survival and apoptosis. This would pave way into understanding the modus operandi of IGFBP-3 in regulating IGF-independent processes and its pleiotropic ability to bind with potential partners thus regulating several cellular functions implicated in metabolic diseases, including cancer.

Fetal Alcohol Exposure Alters Mammary Epithelial Cell Subpopulations and Promotes Tumorigenesis

BACKGROUND

Fetal alcohol exposure (FAE) increases the risk of mammary tumorigenesis in adult offspring; however, the underlying mechanism remains unknown. This study tested the hypothesis that FAE shifts the mammary epithelial cell (MEC) composition toward one that promotes tumorigenesis.

METHODS

Pregnant Friend Virus B NIH Jackson dams bred to MMTV-Wnt1 male mice were given ad libitum access to 5% alcohol in 0.2% saccharin solution from GD9-10 and 10% alcohol in 0.2% saccharin from GD11-GD19 or 0.2% saccharin solution from GD9-GD19. Thoracic and inguinal mammary glands from wild-type (WT) and transgenic (Tg) female offspring were harvested at 5 and 10 weeks of age and dissociated to yield a single cell suspension enriched for MECs for flow cytometry, mammosphere assay, and gene analysis. A subset of Tg offspring was followed for tumor formation.

RESULTS

WT glands of FAE animals exhibited a decreased basal cell population and increased luminal: basal ratio at 10 weeks of age. qRT-PCR analysis of total MECs found that Hey1 mRNA expression was increased in the WT FAE group at 10 weeks of age. In Tg glands, FAE increased the luminal progenitor cell population at 5 weeks of age but did not alter MEC composition at 10 weeks of age. Tertiary mammosphere-forming efficiency was greater in the WT glands of FAE animals at 10 weeks of age. Tumor latency was decreased in the FAE group. Flow cytometry analysis indicated that FAE females developed tumors with an increased basal cell population.

CONCLUSIONS

These data indicate that FAE can shift MEC subpopulations, increasing the proportion of cells that are potentially vulnerable to transformation and affecting cancer risk.

Nuclear localization and actions of the insulin-like growth factor 1 (IGF-1) system components: Transcriptional regulation and DNA damage response

Insulin-like growth factor (IGF) system stimulates growth, proliferation, and regulates differentiation of cells in a tissue-specific manner. It is composed of two insulin-like growth factors (IGF-1 and IGF-2), six insulin-like growth factor-binding proteins (IGFBPs), and two insulin-like growth factor receptors (IGF-1R and IGF-2R). IGF actions take place mostly through the activation of the plasma membrane-bound IGF-Rs by the circulating ligands (IGFs) released from the IGFBPs that stabilize their levels in the serum. This review focuses on the IGF-1 part of the system. The IGF-1 gene, which is expressed mainly in the liver as well as in other tissues, comprises six alternatively spliced exons that code for three protein isoforms (pro-IGF-1A, pro-IGF-1B, and pro-IGF-1C), which are processed to mature IGF-1 and E-peptides. The IGF-1R undergoes autophosphorylation, resulting in a signaling cascade involving numerous cytoplasmic proteins such as AKT and MAPKs, which regulate the expression of target genes. However, a more complex picture of the axis has recently emerged with all its components being translocated to the nuclear compartment. IGF-1R takes part in the regulation of gene expression by forming transcription complexes, modifying the activity of chromatin remodeling proteins, and participating in DNA damage tolerance mechanisms. Four IGFBPs contain a nuclear localization signal (NLS), which targets them to the nucleus, where they regulate gene expression (IGFBP-2, IGFBP-3, IGFBP-5, IGFBP-6) and DNA damage repair (IGFBP-3 and IGFBP-6). Last but not least, the IGF-1B isoform has been reported to be localized in the nuclear compartment. However, no specific molecular actions have been assigned to the nuclear pro-IGF-1B or its derivative EB peptide. Therefore, further studies are needed to shed light on their nuclear activity. These recently uncovered nuclear actions of different components of the IGF-1 axis are relevant in cancer cell biology and are discussed in this review.

IGFBP-3 interacts with NONO and SFPQ in PARP-dependent DNA damage repair in triple-negative breast cancer

Women with triple-negative breast cancer (TNBC) are generally treated by chemotherapy but their responsiveness may be blunted by DNA double-strand break (DSB) repair. We previously reported that IGFBP-3 forms nuclear complexes with EGFR and DNA-dependent protein kinase (DNA-PKcs) to modulate DSB repair by non-homologous end-joining (NHEJ) in TNBC cells. To discover IGFBP-3 binding partners involved in chemoresistance through stimulation of DSB repair, we analyzed the IGFBP-3 interactome by LC-MS/MS and confirmed interactions by coimmunoprecipitation and proximity ligation assay. Functional effects were demonstrated by DNA end-joining in vitro and measurement of γH2AX foci. In response to 20 µM etoposide, the DNA/RNA-binding protein, non-POU domain-containing octamer-binding protein (NONO) and its dimerization partner splicing factor, proline/glutamine-rich (SFPQ) formed complexes with IGFBP-3, demonstrated in basal-like TNBC cell lines HCC1806 and MDA-MB-468. NONO binding to IGFBP-3 was also shown in a cell-free biochemical assay. IGFBP-3 complexes with NONO and SFPQ were blocked by inhibiting EGFR with gefitinib or DNA-PKcs with NU7026, and by the PARP inhibitors veliparib and olaparib, which also reduced DNA end-joining activity and delayed the resolution of the γH2AX signal (i.e. inhibited DNA DSB repair). Downregulation of the long noncoding RNA in NHEJ pathway 1 (LINP1) by siRNA also blocked IGFBP-3 interaction with NONO-SFPQ. These findings suggest a PARP-dependent role for NONO and SFPQ in IGFBP-3-dependent DSB repair and the involvement of LINP1 in the complex formation. We propose that targeting of the DNA repair function of IGFBP-3 may enhance chemosensitivity in basal-like TNBC, thus improving patient outcomes.

IGFBP-3 Induced by Ribotoxic Stress Traffics From the Endoplasmic Reticulum to the Nucleus in Mammary Epithelial Cells

IGF-binding protein (IGFBP)-3 is a multifunctional protein that can exert IGF-independent effects on apoptosis. Anisomycin (ANS) is a potent inducer of IGFBP-3 production in bovine mammary epithelial cells (MECs), and knockdown of IGFBP-3 attenuates ANS-induced apoptosis. IGFBP-3 is present in the nucleus and the conditioned media in response to ANS. The goal of this study was to determine whether ribotoxic stress induced by ANS or a second ribotoxin, deoxynivalenol (DON), specifically regulates transport of IGFBP-3 to the nucleus and to determine the pathway by which it traffics. In ribotoxin-treated cells, both endogenous IGFBP-3 and transfected IGFBP-3 translocated to the nucleus. Inhibition of the nuclear transport protein importin-β with importazole reduced ribotoxin-induced nuclear IGFBP-3. Immunoprecipitation studies showed that ANS induced the association of IGFBP-3 and importin-β, indicating that ribotoxins specifically induce nuclear translocation via an importin-β‒dependent mechanism. To determine whether secretion of IGFBP-3 is required for nuclear localization, cells were treated with Pitstop 2 or brefeldin A to inhibit clathrin-mediated endocytosis or overall protein secretion, respectively. Neither inhibitor affected nuclear localization of IGFBP-3. Although the IGFBP-3 present in both the nucleus and conditioned media was glycosylated, secreted IGFBP-3 exhibited a higher molecular weight. Deglycosylation experiments with endoglycosidase Hf and PNGase indicated that secreted IGFBP-3 completed transit through the Golgi apparatus, whereas intracellular IGFBP-3 exited from the endoplasmic reticulum before transit through the Golgi. In summary, ANS and DON specifically induced nuclear localization of nonsecreted IGFBP-3 via an importin-β‒mediated event, which may play a role in their ability to induce apoptosis in MECs.

Dual targeting of Nur77 and AMPKα by isoalantolactone inhibits adipogenesis in vitro and decreases body fat mass in vivo

BACKGROUND

Suppression of adipogenesis has been considered as a potential target for the prevention and treatment of obesity and associated metabolic disorders, and the nuclear receptor 4A1 (NR4A1/Nur77) and AMPKα are known to play important roles during early and intermediate stages of adipogenesis. Therefore, we hypothesized that dual targeting Nur77 and AMPKα would show strong inhibitory effect on adipogenesis.

METHODS

We screened a herbal medicine-based small molecule library to identify novel natural compounds dual targeting Nur77 and AMPKα, and the antiadipogenic effects and mechanisms of action of a "hit" compound were studied in 3T3-L1 cells. In vivo antiobesity effects of the compound were also investigated in high-fat diet (HFD)-induced obese mice.

RESULTS

We identified isoalantolactone (ISO) as a new NR4A1 inactivator that also activates AMPKα in 3T3-L1 cells. ISO, as expected, inhibited adipogenic differentiation of 3T3-L1 preadipocytes, accompanied by reduced mitotic clonal expansion (MCE) which occurs in the early stage of adipogenesis and decreased expression of genes required for MCE and cell cycle markers including cyclin A, cyclin D1. Furthermore, ISO reduced body weight gain and fat mass (epididymal, subcutaneous, perirenal, and inguinal white adipose tissues) in the high-fat diet-fed C57BL/6 N mice. Serum levels of triglycerides, aspartate transaminase, and alanine transaminase and hepatic steatosis were also significantly improved in the ISO-treated group compared to the high-fat diet control group.

CONCLUSIONS

These results suggest that ISO dual targeting Nur77 and AMPKα during adipogenesis represents a novel class of mechanism-based antiadipogenic agents for treatment of obesity and associated metabolic disorders, including hyperlipidemia and fatty liver.

Characteristics of Nur77 and its ligands as potential anticancer compounds (Review)

Nuclear receptor subfamily 4 group A member 1 (NR4A1; also termed Nur77/TR3/NGFIB), a member of the nuclear receptor superfamily, is expressed as an early response gene to regulate the expression of multiple target genes. Nur77 has the typical structure of a nuclear receptor, including an N‑terminal domain, a DNA binding domain, and a ligand‑binding domain. The expression and localization of Nur77 are closely associated with its roles in cell proliferation and apoptosis. Nur77 was first identified as an orphan receptor, the endogenous ligand of which has not yet been identified; however, an increasing number of compounds targeting Nur77 have been reported to have beneficial effects in the treatment of cancer and other diseases. This review provides a brief overview of the identification, structure, expression and localization, transcriptional role and non‑genomic function of Nur77, and summarizes the ligands that have been shown to interact with Nur77, including cytosporone B, cisplatin, TMPA, PDNPA, CCE9, THPN, Z‑ligustilide, celastrol and bisindole methane compounds, which may potentially be used to treat cancer in humans.

Lactobacillus casei Strain Shirota Enhances the In Vitro Antiproliferative Effect of Geniposide in Human Oral Squamous Carcinoma HSC-3 Cells

This study investigated the enhanced antiproliferative effect of Lactobacillus casei strain Shirota (LcS) on geniposide actions in human oral squamous carcinoma HSC-3 cells. An MTT assay, flow cytometry, qPCR assay, western blot and HPLC were used for this study. The concentration of 1.0 × 10⁶ CFU/mL of LcS had no effect on the HOK normal oral epithelial cells and HSC-3 cancer cells. The 25 and 50 µg/mL geniposide concentrations also had no impact on HOK normal oral epithelial cells, but they had remarkable inhibitory effects on the growth of HSC-3 cancer cells, which are enhanced in the presence of LcS. By the flow cytometry assay, the LcS-geniposide-H (1.0 × 10⁶ CFU/mL LcS and 50 µg/mL geniposide)-treated HSC-3 cancer cells had the largest number of cells undergoing apoptosis compared to cells treated with other combinationsand obviously more than cells treated with only geniposide-H (50 µg/mL geniposide). Geniposide-H could increase the mRNA and protein expressions of caspase-3, caspase-8, caspase-9, Bax, p53, p21, IκB-α, Fas, FasL, TIMP-1, and TIMP-2 as well as decrease those of Bcl-2, Bcl-xL, HIAP-1, HIAP-2, NF-κB, COX-2, iNOS, MMP-2, and MMP-9 compared to other groups of cells, and LcS further enhanced these changes, with results that are greater than for the cells treated with only a high concentration of geniposide. The results of this study show thatLcS enhanced the antiproliferative effect of geniposide in HSC-3 cancer cells.

Nur77 suppression facilitates androgen deprivation-induced cell invasion of prostate cancer cells mediated by TGF-β signaling

BACKGROUND

Androgen deprivation therapy (ADT) remains a standard treatment for advanced prostate cancers. However, recent studies revealed that while inhibiting the growth of certain types of prostate cancer cells, ADT promotes invasion. In the current study, we explored the effects of Nur77, an orphan nuclear receptor, on prostate cancer cell invasion following ADT.

METHODS

Androgen receptor (AR) and Nur77 protein expression in patient tissues and cell lines were quantified via ELISA and western blot. The effects of AR-signaling on Nur77 expression were examined. The effects of Nur77 over-expression and knockdown on ADT-induced prostate cancer cell invasion were characterized.

RESULTS

The results showed that AR and Nur77 are both highly expressed in prostate cancers of patients. Nur77 is positively regulated by AR-signaling at transcriptional level in NCI-H660, a widely used prostate cancer cell line. AR antagonists, Casodex and MDV3100 treatment resulted in significant inhibition of prostate cancer cell growth but enhanced cancer cell invasion. Nur77 over-expression blocked invasion-promoting effect of ADT, which is consistent with the down-regulation of MMP9 and Snail protein expression. Further mechanistic investigations showed that Nur77 inhibited transcription of TGF-β target genes (Snail and MMP9), and thereby inhibits TGF-β-mediated prostate cancer cell invasion following androgen antagonism. In addition, our data suggested the nature of this inhibitory effect of Nur77 on TGF-β-signaling is selective, for Smad3-signaling, the classical effector of TGF-β-signaling, was not interrupted by Nur77 over-expression.

CONCLUSION

Considering the limited success of management of prostate cancer metastasis following ADT, our data strongly suggest that Nur77 regulation could be a promising direction for search of complementary therapeutic strategy on top of classic ADT therapy.

Resveratrol enhances anticancer effects of paclitaxel in HepG2 human liver cancer cells

BACKGROUND

The aim of this in vitro study was to measure the enhanced anticancer effects of Res (resveratrol) on PA (paclitaxel) in HepG2 human liver cancer cells.

METHODS

The MTT (thiazolyl blue tetrazolium bromide, 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide), flow cytometry, qPCR (real-time quantitative polymerase chain reaction) and western blot assay were used for cells growth inhibitory effects, cells apoptosis (DNA content of sub-G1), mRNA and protein expressions, respectively.

RESULTS

The 10 μg/mL of Res had no growth inhibitory effect on Nthy-ori 3-1 normal cells or HepG2 cancer cells meanwhile the 5 or 10 μg/mL of PA also had no growth inhibitory effect on Nthy-ori 3-1 normal cells. Where as PA-L (5 μg/mL) and PA-H (10 μg/mL) had the growth inhibitory effects in HepG2 cancer cells, and Res increase these growth inhibitory effects. By flow cytometry experiment, after Res (5 μg/mL) + PA-H (10 μg/mL) treatment, the HepG2 cells showed the most apoptosis in cells as compared to other treatments groups, and after additionally treated with Res, both the apoptosis cells of two concentrations PA were raised. As PA raised it also raised the mRNA and protein expressions of caspase-3, caspase-8, caspase-9, Bax (Bcl-2 assaciated X protein), p53, p21, IκB-α (inhibitor of NF-κB alpha), Fas (factor associated suicide), FasL (factor associated suicide ligand), TIMP-1 (tissue inhibitor of metalloproteinases 1), TIMP-2 (tissue inhibitor of metalloproteinases 2) and decrease Bcl-2 (B cell leukemia 2), Bcl-xL (B cell leukemia extra large), HIAP-1 (cIAP-1, cellular inhibitor of apoptosis 1), HIAP-2 (cIAP-2, cellular inhibitor of apoptosis 2), NF-κB (nuclear factor kappa B), COX-2 (cyclooxygenase 2), iNOS (inducible nitric oxide synthase), MMP-2 (metalloproteinase 2), MMP-9 (metalloproteinase 9), EGF (epidermal growth factor), EGFR (epidermal growth factor receptor), VEGF (vascular endothelial growth factor), Fit-1 (VEGFR-1, vascular endothelial growth factor receptor 1). Meanwhile, the 5 μg/mL of Res could enhance these mRNA expressions changes as compared to the control cells.

CONCLUSION

From these results, we can conclude that Res could raise the anticancer effects of PA in HepG2 cells, Res could be used as a good sensitizing agent for PA.

Ginsenoside 20(S)-Rh2 Induces Apoptosis and Differentiation of Acute Myeloid Leukemia Cells: Role of Orphan Nuclear Receptor Nur77

Ginsenoside 20(S)-Rh2 has been shown to induce apoptosis and differentiation of acute myeloid leukemia (AML) cells. However, the underlying molecular mechanisms are not fully understood. In our study, 20(S)-Rh2 induced the expression of orphan nuclear receptor Nur77 and death receptor proteins Fas, FasL, DR5, and TRAIL, as well as the cleavage of caspase 8 and caspase 3 in HL-60 cells. Importantly, shNur77 attenuated 20(S)-Rh2-induced apoptosis and Fas and DR5 expression. Meanwhile, 20(S)-Rh2 promoted Nur77 translocation from the nucleus to mitochondria and enhanced the interaction between Nur77 and Bcl-2, resulting in the exposure of the BH3 domain of Bcl-2 and activation of Bax. Furthermore, 20(S)-Rh2 promoted the differentiation of HL-60 cells as evidenced by Wright-Giemsa staining, NBT reduction assay, and detection of the myeloid differentiation marker CD11b by flow cytometry. Notably, shNur77 reversed 20(S)-Rh2-mediated HL-60 differentiation. Additionally, 20(S)-Rh2 also exhibited an antileukemic effect and induced Nur77 expression in NOD/SCID mice with the injection of HL-60 cells into the tail vein. Together, our studies suggest that the Nur77-mediated signaling pathway is highly involved in 20(S)-Rh2-induced apoptosis and differentiation of AML cells.

Lactobacillus raises in vitro anticancer effect of geniposide in HSC-3 human oral squamous cell carcinoma cells

The present study determined the ability of the Lactobacillus rhamnosus GG strain (LGG) to enhance the anticancer effects of geniposide on HSC-3 human oral squamous carcinoma cells. LGG (1.0×10³ CFU/ml) on its own had no impact on human oral keratinocytes and HSC-3 cancer cells. Geniposide (25 or 50 µg/ml) had no impact on human oral keratinocytes, but exerted growth inhibitory effects on HSC-3 cancer cells, which were increased in the presence of LGG. Flow cytometric analysis and a nuclear staining assay with DAPI revealed that HSC-3 cancer cells treated with LGG-geniposide (1.0×10³ CFU/ml LGG and 50 µg/ml geniposide) had a higher apoptotic rate than cells in other treatment groups, particularly that treated with geniposide (50 µg/ml) only. Geniposide also increased the mRNA and protein expression of caspase-3, -8 and -9 as well as B-cell lymphoma 2 (Bcl-2)-associated X protein, p53, p21, inhibitor of nuclear factor-κB (NF-κB) α, Fas and Fas ligand, while decreasing Bcl-2, Bcl extra large protein, inhibitor of apoptosis-1 and -2, NF-κB, cyclooxigenase-2 and inducible nitric oxide synthase in HSC-3 cells, which was increased in the presence of LGG. These results indicated that LGG enhanced the anticancer effects of geniposide in HSC-3 cells.

Bone marrow-derived mesenchymal stem cells modified with IGFBP-3 inhibit the proliferation of pulmonary artery smooth muscle cells

Pulmonary arterial hypertension (PAH) is a common clinical cardiovascular disease, leading to the excessive proliferation of pulmonary artery smooth muscle cells (PASMCs) and endothelial cells, and is associated with a high mortality rate. Recently, stem- and progenitor cell-mediated gene therapies have provided a novel approach for the treatment of PAH. However, the function of human bone marrow-derived mesenchymal stem cells (hBM‑MSCs) modified with the insulin-like growth factor binding protein-3 (IGFBP-3) gene in the regulation of PAH is not yet fully understood. In this study, we explored the biological role of IGFBP‑3-modified hBM‑MSCs in the proliferation of human PASMCs (hPASMCs), and also investigated the potential underlying molecular mechanisms. Our results revealed that IGFBP-3-modified hBM‑MSCs inhibited the proliferation of angiotensin II-stimulated hPASMCs following co-culture on cell culture inserts. In addition, total DNA synthesis and the protein levels of hPASMCs in co-culture were decreased. Moreover, the IGFBP‑3-modified hBM‑MSCs promoted apoptosis and downregulated the expression of B-cell lymphoma-2 (Bcl-2), but increased the expression of Bcl-2 associated X protein (Bax) in hPASMCs. Furthermore, the IGFBP‑3-modified hBM‑MSCs significantly induced a phenotypic change in the hPASMCs from the synthetic to the contractile phenotype in co-culture. Importantly, the levels of several related proteins in the hPASMCs, including phosphorylated (p-)insulin receptor substrate-1 (p-IRS-1), phosphoinositide 3-kinase (p-PI3K), serine/threonine-protein kinase (p-Akt), mitogen-activated protein kinase (p-p38), p-Jun N-terminal kinase (p-JNK) and extracellular signal-regulated kinase (p-ERK), were markedly decreased by the IGFBP-3-modified hBM‑MSCs following co-culture. Taken together, our findings suggest that IGFBP-3-modified hBM‑MSCs inhibit the proliferation and promote the apoptosis of hPASMCs, and promote the swithc to a contractile phenotype in more effectively than wild-type hBM‑MSCs, possibly through the activation of the PI3K/Akt and Ras-mitogen-activated protein kinase (MAPK) signaling pathways. The findings of our study suggest that IGFBP‑3‑modified hBM‑MSCs may be a promising therapeutic strategy for the treatment of PAH.

Tumor Phenotype and Gene Expression During Early Mammary Tumor Development in Offspring Exposed to Alcohol In Utero

BACKGROUND

Alcohol exposure in utero increases susceptibility to carcinogen-induced mammary tumorigenesis in adult offspring and causes tumors with a more malignant phenotype. This study was conducted to identify changes early in tumor development that might lead to this outcome.

METHODS

Pregnant Sprague-Dawley rats were fed a liquid diet containing 6.7% ethanol (alcohol), an isocaloric liquid diet without alcohol (pair-fed), or rat chow ad libitum (ad lib) from gestation day 7 until parturition. At birth, female progeny were cross-fostered to control dams. Pups were weaned at postnatal day (PND) 21 and fed rat chow ad libitum for the remainder of the experiment. Female offspring were administered N-nitroso-N-methylurea (NMU; 50 mg/kg body weight) on PND 50. Mammary glands were palpated weekly, and offspring were euthanized at 16 weeks post-NMU injection.

RESULTS

At 16 weeks post-NMU, tumor multiplicity was greater in alcohol-exposed offspring compared with control groups. Estrogen receptor-α (ER) mRNA expression was decreased in tumors from alcohol-exposed offspring, and these animals developed more ER-negative tumors relative to the pair-fed group. Alcohol-exposed offspring also tended to develop more progesterone receptor (PR)-positive tumors. All tumors were HER2-negative. PR positivity was associated with higher Ki67 expression, suggesting that PR-positive tumors were more proliferative. Tumors from alcohol-exposed animals exhibited increased mRNA expression of the insulin-like growth factor (IGF) family members IGF-II and IGFBP-5. IGF-II and DNA methyltransferase mRNA tended to be greater in the normal contralateral mammary glands of these animals.

CONCLUSIONS

These data indicate that alcohol exposure in utero may shift NMU-induced tumor development toward a more aggressive phenotype and that alterations in IGF-II expression may contribute to these changes. Additional studies should be aimed at epigenetic mechanisms that underlie IGF-II expression to further delineate how this gene is altered in mammary glands of adults exposed to alcohol in utero.