ZBTB28 inhibits breast cancer by activating IFNAR and dual blocking CD24 and CD47 to enhance macrophages phagocytosis.

Breast cancer is the leading cause of cancer death in female. Until now, advanced breast cancer is still lack effective treatment strategies and reliable prognostic markers. In the present article, we introduced the physiologic and pathologic functions and regulation mechanisms of ZBTB28, a tumor suppressor gene, in breast cancer. ZBTB28 is frequently silenced in breast cancer due to promoter CpG methylation, and its expression is positively correlated with breast cancer patient survival. The antineoplastic effect of ZBTB28 in breast cancer was elucidated through a series of in vitro and in vivo measurements, including cell proliferation, apoptosis, cell cycle, epithelial mesenchymal transition (EMT), and growth of xenografts. Furthermore, ZBTB28 can directly regulate IFNAR to activate interferon-stimulated genes and potentiate macrophage activation. Ectopic ZBTB28 expression in breast cancer cells was sufficient to downregulate CD24 and CD47 to promote phagocytosis of macrophages, demonstrating that ZBTB28 was beneficial for the combination treatment of anti-CD24 and anti-CD47. Collectively, our results reveal a mode of action of ZBTB28 as a tumor suppressor gene and suggest that ZBTB28 is an important regulator of macrophage phagocytosis in breast cancer, holding promise for the development of novel therapy strategies for breast cancer patients.

Quinone Pool, a Key Target of Plant Flavonoids Inhibiting Gram-Positive Bacteria.

Plant flavonoids have attracted increasing attention as new antimicrobial agents or adjuvants. In our previous work, it was confirmed that the cell membrane is the major site of plant flavonoids acting on the Gram-positive bacteria, which likely involves the inhibition of the respiratory chain. Inspired by the similar structural and antioxidant characters of plant flavonoids to hydro-menaquinone (MKH2), we deduced that the quinone pool is probably a key target of plant flavonoids inhibiting Gram-positive bacteria. To verify this, twelve plant flavonoids with six structural subtypes were preliminarily selected, and their minimum inhibitory concentrations (MICs) against Gram-positive bacteria were predicted from the antimicrobial quantitative relationship of plant flavonoids to Gram-positive bacteria. The results showed they have different antimicrobial activities. After their MICs against Staphylococcus aureus were determined using the broth microdilution method, nine compounds with MICs ranging from 2 to 4096 µg/mL or more than 1024 µg/mL were eventually selected, and then their MICs against S. aureus were determined interfered with different concentrations of menaquinone-4 (MK-4) and the MKs extracted from S. aureus. The results showed that the greater the antibacterial activities of plant flavonoids were, the more greatly their antibacterial activities decreased along with the increase in the interfering concentrations of MK-4 (from 2 to 256 µg/mL) and the MK extract (from 4 to 512 µg/mL), while those with the MICs equal to or more than 512 µg/mL decreased a little or remained unchanged. In particular, under the interference of MK-4 (256 µg/mL) and the MK extract (512 µg/mL), the MICs of α-mangostin, a compound with the greatest inhibitory activity to S. aureus out of these twelve plant flavonoids, increased by 16 times and 8 to 16 times, respectively. Based on the above, it was proposed that the quinone pool is a key target of plant flavonoids inhibiting Gram-positive bacteria, and which likely involves multiple mechanisms including some enzyme and non-enzyme inhibitions.

Streptomyces pimonensis sp. nov., isolated from the Taklimakan desert in Xinjiang, China.

A novel Streptomyces strain, designated TRM 75549T, was isolated from a sample of sand in Pimo reclamation area, Taklimakan desert, Xinjiang, North-West China. Phylogenetic analyses of the 16S rRNA gene sequences placed strain TRM75549T within the genus Streptomyces with the highest similarities to Streptomyces pilosus NBRC 12772T (98.7%). Nonetheless, average nucleotide identity (ANI) value and the digital DNA-DNA hybridization (dDDH) value between strain TRM75549T and S. pilosus NBRC 12772T were, respectively, 88.2% and 44.1%, and well below 95-96% and 70% cutoff point recommended for recognizing genomospecies, respectively. A multi-locus sequence analysis of five house-keeping genes (atpD, gyrB, recA, rpoB and trpB) and phylogenomic analysis also illustrated that strain TRM75549T should also be assigned to the genus Streptomyces. Strain TRM75549T contained MK-9 (H6) and MK-9 (H8) as predominant menaquinones. The diagnostic diamino acid of cell walls were identified as LL-diaminopimelic acid and meso-diaminopimelic. The whole-cell sugar pattern of strain TRM 75549T consisted of mannose and glucose. The major fatty acids (> 5%) were iso-C14:0, iso-C15:0, anteiso-C15:0, iso-C16:1H, iso-C16:0. The polar lipids were diphosphatidylglycerol, lysophosphatidylglycerol, phosphatidylethanolamine, phospholipids, phosphatidylglycerol, phosphatidylinositol, phosphatiylinositol mannosides and unidentified phospholipids. Strain TRM75549T could be differentiated from S. pilosus NBRC 12772T, based on physiological and biochemical characteristics. Thus, strain TRM75549T is representative of a novel species of the genus Streptomyces, for which the name Streptomyces pimonensis sp. nov. is proposed. The type strain is TRM75549T (= CCTCC AA 2020054T = LMG 32221T).

Poly(ADP-ribose) polymerase-1 promotes recruitment of meiotic recombination-11 to chromatin and DNA double-strand break repair in Ku70-deficient breast cancer cells.

Poly(ADP-ribose) polymerase (PARP)-1 may act in an error-prone pathway called alternative end joining (Alt-EJ) for DNA double-strand break (DSB) repair when nonhomologous end joining is defective. We examined the recruitment of PARP-1 to chromatin in response to radiomimetic agents and the effects of PARP-1 inhibition on DSB repair and recruitment of the meiotic recombination (MRE)-11-double-strand break repair (RAD50) protein-Nijmegen breakage syndrome (NSB)-1 (MRN) complex to the chromatin in Ku70-deficient breast cancer cells. The chromatin-binding affinity of PARP-1 was enhanced in response to neocarzinostatin (NCS) or calicheamicin treatment in the absence of Ku70. PARP-1 inhibition impaired the repair of both NCS-induced DSBs and intron-encoded endonuclease from Physarum polycephalum-induced site-specific DSB. Both fractionation and chromatin immunoprecipitation assays demonstrated that chromatin recruitment of MRN was PARP-1 dependent. These data suggest that PARP-1 is vital for DSB repair in breast cancer cells when Alt-EJ is activated.-Huang, Y., Shao, Q., Luo, X., Yang, D., Zeng, B., Xiang, T., Ren, G., Cheng, Q. Poly(ADP-ribose) polymerase-1 promotes recruitment of meiotic recombination-11 to chromatin and DNA double-strand break repair in Ku70-deficient breast cancer cells.

Methylation of PLCD1 and adenovirus-mediated PLCD1 overexpression elicits a gene therapy effect on human breast cancer.

Our previous study showed that PLCD1 significantly decreases cell proliferation and affects cell cycle progression in breast cancer cells. In the present study, we aimed to investigate its functional and molecular mechanisms, and whether or not can become a new target for gene therapies. We found reduced PLCD1 protein expression in breast tumor tissues compared with paired surgical margin tissues. PLCD1 promoter CpG methylation was detected in 55 of 96 (57%) primary breast tumors, but not in surgical-margin tissues and normal breast tissues. Ectopic expression of PLCD1 inhibited breast tumor cell proliferation in vivo by inducing apoptosis and suppressed tumor cell migration by regulating cytoskeletal reorganization proteins including RhoA and phospho-cofilin. Furthermore, we found that PLCD1 induced p53 accumulation, increased p27 and p21 protein levels, and cleaved PARP. Finally, we constructed an adenoviral vector expressing PLCD1 (AdH5-PLCD1), which exhibited strong cytotoxicity in breast cancer cells. Our findings provide insights into the development of PLCD1 gene therapies for breast cancer and perhaps, other human cancers.

Chrysin inhibits metastatic potential of human triple-negative breast cancer cells by modulating matrix metalloproteinase-10, epithelial to mesenchymal transition, and PI3K/Akt signaling pathway.

Chrysin, a naturally occurring flavone, has been shown to inhibit cell proliferation and induce cell apoptosis in various cancers. However, the effect and mechanisms of chrysin on cancer metastasis are still enigmatic. In this study, metastatic triple-negative breast cancer (TNBC) cell lines were used to evaluate the antimetastatic activity of chrysin. The results showed that chrysin (5, 10 and 20 µM) significantly suppressed TNBC cell migration and invasion in a dose-dependent manner. Human matrix metalloproteinase (MMP) antibody array demonstrated that MMP-10 was downregulated by chrysin, which was further verified by Western blotting and ELISA. Moreover, it was shown that chrysin induced increased E-cadherin expression and decreased expression of vimentin, snail and slug in TNBC cells, suggesting that chrysin had a reversal effect on epithelial-mesenchymal transition. More importantly, it was demonstrated that inhibiting the Akt signal pathway might play a central role in chrysin-induced antimetastatic activity by regulating MMP-10 and epithelial-mesenchymal transition. In conclusion, our study indicates that chrysin exerts antimetastatic activities in TNBC cells, which suggests that chrysin might be a potential therapeutic candidate for the treatment of advanced or metastatic breast cancer.

DACT1, an antagonist to Wnt/ß-catenin signaling, suppresses tumor cell growth and is frequently silenced in breast cancer.

INTRODUCTION: Aberrant activation of Wnt/ß-catenin signaling plays an important role in the pathogenesis of breast cancer. DACT1 (Dapper/Frodo) has been identified as involved in antagonizing Wnt/ß-catenin signaling through interacting with Dishevelled (Dvl), a central mediator of Wnt signaling, whereas its role in breast tumorigenesis remains unclear. METHODS: We examined DACT1 expression in breast cancer cell lines and primary tumors with semiquantitative or quantitative RT-PCR and immunochemistry, and further evaluated the promoter methylation of DACT1 with methylation-specific PCR (MSP). We also explored the tumor-suppressive functions of DACT1 in vivo and in vitro, and its related mechanism in breast cancer. RESULTS: We identified DACT1 as a methylated target in our breast cancer epigenome study. Here, we further investigated DACT1 expression in multiple breast cell lines and primary tumors, and further studied its function and molecular mechanisms. We found that DACT1 expression was silenced in eight (88.9%) of nine breast cancer cell lines, and its protein levels were obviously reduced in breast tumors compared with paired surgical-margin tissues. Promoter CpG methylation of DACT1 was detected in five (55.6%) of nine breast cancer cell lines and 40 (29.9%) of 134 primary tumors, but not in surgical-margin tissues and normal breast tissues. Demethylation treatment of breast cancer cell lines restored DACT1 expression along with promoter demethylation, suggesting that an epigenetic mechanism mediates DACT1 silencing in breast cancer. Functional assays showed that ectopic expression of DACT1 could inhibit breast tumor cell proliferation in vivo and in vitro through inducing apoptosis, and further suppress tumor cell migration through antagonizing the Wnt/ß-catenin signaling pathway. CONCLUSIONS: Our study demonstrates that DACT1 could function as a tumor suppressor but was frequently downregulated in breast cancer.

Capecitabine-based chemotherapy in early-stage triple-negative breast cancer: a meta-analysis.

Introduction: The efficacy and safety of adjuvant capecitabine in early-stage triple-negative breast cancer remains undefined. A meta-analysis was conducted to elucidate whether capecitabine-based regimens could improve survival in early-stage triple-negative breast cancer (TNBC). Methods: The current study searched Medline, Embase, Cochrane Library, Web of Science, and ClinicalTrials.gov proceedings up to 2023.9. Disease-free survival (DFS), overall survival (OS), and grade 3-4 adverse events (AEs) were assessed. Extracted or calculated hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs) were pooled. Results: The capecitabine-based regimens showed significant advantages in DFS (HR = 0.81, 95% CI: 0.73-0.90; P <.001) and OS (HR = 0.75, 95% CI: 0.65-0.87; P <.001) from 12 randomized controlled trials (RCTs) with 5,390 unselected participants. Subgroup analysis of DFS showed analogous results derived from patients with lymph node negative (HR = 0.68, 95% CI: 0.50-0.92; P = .006) and capecitabine duration no less than six cycles (HR = 0.73; 95% CI: 0.62-0.86; P <.001). Improvement of DFS in the addition group (HR = 0.77, 95% CI: 0.68-0.87; P <.001) and adjuvant setting (HR = 0.79, 95% CI: 0.70-0.89; P <.001) was observed. As to safety profile, capecitabine was associated with more frequent stomatitis (OR = 5.05, 95% CI: 1.45-17.65, P = .011), diarrhea (OR = 6.11, 95% CI: 2.12-17.56; P =.001), and hand-foot syndrome (OR = 31.82, 95% CI: 3.23-313.65, P = .003). Conclusions: Adjuvant capecitabine-based chemotherapy provided superior DFS and OS to early-stage TNBC. The benefits to DFS in selected patients with lymph node negative and the addition and extended duration of capecitabine were demonstrated.

A nomogram for survival prediction in 275,812 U.S. patients with breast cancer: a population-based cohort study based on the SEER database.

Background: Nomograms can assess the risk of clinicopathological features by quantifying the biological and clinical variables of cancer patients. However, the nomogram based on significant factors that influence the survival of breast cancer in a large population has been rarely explored. This study was to investigate the predictive effectiveness of a nomogram for the survival of patients with breast cancer. Methods: Demographic and clinical data of 275,812 breast cancer patients were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. All patients aged ≥20 years in this retrospective cohort study were classified as two groups in a random manner, namely the training set (n=193,069) and validation set (n=82,743). The outcomes of our study were the 3- and 5-year survival of breast cancer. The potential predictors of cancer mortality were screened by univariate and multivariable Cox regression analyses. The nomogram was conducted based on the predictors. Harrell's concordance index (C-index), receiver operating characteristic (ROC) curves and calibration curve was utilized to evaluate the performance of the nomogram. Results: The age at diagnosis, race, marital status, tumor size, first malignant primary indicator, American Joint Committee on Cancer (AJCC) T stage, M stage, tumor grade, and number of malignant tumors were independent predictors for the death of patients with breast cancer. The C-indexes of the training set and the validation set were 0.782 and 0.778, respectively. The area under the curve (AUC) values of the nomogram for predicting the 3- and 5-year survival of breast cancer were 0.770 and 0.756, respectively. Furthermore, the C-index values of our nomogram were 0.816, 0.775, 0.773, 0.734, and 0.750 for predicting survival in Asian, White, Hispanic, American Indian, and Black populations, respectively. Conclusions: The nomogram may have predictive performance for predicting the 3- and 5-year survival of breast cancer patients, and future studies need to validate our findings.

Mining immune-related genes with prognostic value in the tumor microenvironment of breast invasive ductal carcinoma.

ABSTRACT: The tumor microenvironment (TME) plays an important role in the development of breast cancer. Due to limitations in experimental conditions, the molecular mechanism of TME in breast cancer has not yet been elucidated. With the development of bioinformatics, the study of TME has become convenient and reliable.Gene expression and clinical feature data were downloaded from The Cancer Genome Atlas database and the Molecular Taxonomy of Breast Cancer International Consortium database. Immune scores and stromal scores were calculated using the Estimation of Stromal and Immune Cells in Malignant Tumor Tissues Using Expression Data algorithm. The interaction of genes was examined with protein-protein interaction and co-expression analysis. The function of genes was analyzed by gene ontology enrichment analysis, Kyoto Encyclopedia of Genes and Genomes analysis and gene set enrichment analysis. The clinical significance of genes was assessed with Kaplan-Meier analysis and univariate/multivariate Cox regression analysis.Our results showed that the immune scores and stromal scores of breast invasive ductal carcinoma (IDC) were significantly lower than those of invasive lobular carcinoma. The immune scores were significantly related to overall survival of breast IDC patients and both the immune and stromal scores were significantly related to clinical features of these patients. According to the level of immune/stromal scores, 179 common differentially expressed genes and 5 hub genes with prognostic value were identified. In addition, the clinical significance of the hub genes was validated with data from the molecular taxonomy of breast cancer international consortium database, and gene set enrichment analysis analysis showed that these hub genes were mainly enriched in signaling pathways of the immune system and breast cancer.We identified five immune-related hub genes with prognostic value in the TME of breast IDC, which may partly determine the prognosis of breast cancer and provide some direction for development of targeted treatments in the future.

Dual inhibition of Akt and ERK signaling induces cell senescence in triple-negative breast cancer.

Activated Akt and ERK signaling pathways are closely related to breast cancer progression, and Akt or ERK inhibition induces cell senescence. However, the crosstalk between the Akt and ERK signaling pathways in cell senescence and how to simultaneously suppress Akt and ERK signaling in triple-negative breast cancer (TNBC) are undefined. In this study, we found that norcantharidin (NCTD) effectively induced cell senescence and cell cycle arrest in TNBC in vitro, which was accompanied by a decline in phosphorylated Akt and ERK1/2 and a rise in p21 and p16. The inhibitors LY294002 and U0126 imitated the effect of NCTD when these two inhibitors were combined regardless of crosstalk between these two signaling pathways. In addition, NCTD inhibited the growth of xenografts via downregulation of phosphorylated Akt and ERK1/2 and upregulation of p21 in vivo. However, NCTD upregulated the level of soluble signaling factors of the senescence-associated secretory phenotype (SASP) in a NF-κB-independent manner. Collectively, these findings demonstrate that NCTD induced cell senescence and cell cycle arrest mainly by simultaneously blocking Akt and ERK signaling in TNBC, suggesting that NCTD may be used as a potential adjuvant therapy in TNBC.

Paired box 5 is a novel marker of breast cancers that is frequently downregulated by methylation.

Identifying markers for breast cancer is important for both diagnosis and the design of treatment strategies. Recent studies have implicated Paired box 5 (PAX5) as a suppressor in various cancer types, where it is silenced by hypermethylation. However, determining the role of PAX5 in breast cancer requires further study, and the relationship between PAX5 methylation and breast cancer remains unclear. In this study, we found that PAX5 expression was frequently silenced or reduced by methylation in breast cancer cell lines as well as in breast cancer tissues. Restoring expression of PAX5 in breast cancer cells led to tumor suppression through inhibited proliferation and invasion, which resulted from modulation of the cell cycle and altered vascular endothelial growth factor (VEGF) expression. Most importantly, we found that PAX5 methylation status in breast cancer tissues was significantly correlated with patients' age, estrogen receptor (ER) status, progesterone receptor (PR) status, indicating that PAX5 could serve as a marker for breast cancer diagnosis and treatment strategy design.

The tumor suppressor interferon regulatory factor 8 inhibits ß-catenin signaling in breast cancers, but is frequently silenced by promoter methylation.

Interferon (IFN) regulatory factor 8 is encoded by a novel candidate tumor suppressor gene (IRF8), its promotor is frequently methylated in multiple cancers. However, the promoter methylation status, functions and underlying mechanisms of IRF8 in breast cancer remain unclear. We found that IRF8 was downregulated in breast cancer cell lines and primary tumors, compared with normal breast tissues, mainly because of aberrant promoter methylation. However, its expression was not associated with pathological characteristics. Restoration of IRF8 expression suppressed cell proliferation, colony formation, 5-ethynyl-2'-deoxyuridine incorporation, cell migration and invasion, and induced apoptosis and cell cycle arrest in vitro. IRF8 also inhibited xenograft growth in nude mice in vivo. Competition with IRF8 function by IRF8 mutant (K79E) enhanced cell migration and invasion in 4T1 murine cells in vitro. Importantly, IRF8, as both downstream target gene and regulator of IFN-γ/STAT1 signaling, inhibited canonical ß-catenin signaling. These findings identify IRF8 as a novel tumor suppressor regulating IFN-γ/STAT1 signaling and ß-catenin signaling in breast cancer.

Phospholipase Cδ1 suppresses cell migration and invasion of breast cancer cells by modulating KIF3A-mediated ERK1/2/ß- catenin/MMP7 signalling.

Phospholipase C δ1 (PLCD1) encodes an enzyme involved in energy metabolism, calcium homeostasis and intracellular movement. It is located at 3p22 in a region that is frequently deleted in multiple cancers, and the PLCD1 enzyme is a potential tumour suppressor in breast cancer that inhibits matrix metalloprotease (MMP) 7, but the detailed mechanism remains elusive. In this study, we found that PLCD1 was downregulated in breast cancers, and the gain-or-loss functional assay revealed that PLCD1 inhibited cell migration and invasion in vitro via the ERK1/2/ß-catenin/MMP7 signalling pathway. Furthermore, KIF3A was identified as a downstream mediator of PLCD1, and there was an inverse correlation between the expression of PLCD1 and KIF3A. Knockdown of KIF3A expression alone suppressed cell migration and invasion, and attenuated ERK1/2/ß-catenin/MMP7 signalling that was reactivated by knocking down PLCD1 in vitro. Collectively, our findings suggest that PLCD1 acts as a tumour suppressor, by KIF3A-mediated suppression of ERK1/2/ß-catenin/MMP7 signalling, at least in part, in breast cancer.

Protocadherin 17 functions as a tumor suppressor suppressing Wnt/ß-catenin signaling and cell metastasis and is frequently methylated in breast cancer.

Protocadherins play important roles in the regulation of cell adhesion and signaling transduction. Aberrant expression of protocadherins has been shown to be associated with multiple tumorigenesis. We previously identified PCDH17, encoding protocadherin 17, as a frequently methylated and downregulated tumor suppressor gene (TSG) in gastric and colorectal cancers. Here, we examined the abnormalities and functions of PCDH17 in breast cancer pathogenesis. We used PCR and immunohistochemistry to check its expression pattern in breast tumor cell lines and primary tumors. Methylation-specific PCR (MSP) was applied to examine its promoter methylation status in breast tumor cell lines and primary tumors. The biological functions of PCDH17 in breast tumor cells were assessed using in vitro and in vivo assays. We found that PCDH17 was frequently downregulated or silenced in 78% (7/9) of breast tumor cell lines, as well as 89% (32/36) of primary tumors. Downregulation of PCDH17 in breast cancer was mainly due to the methylation of its promoter. Ectopic expression of PCDH17 in breast tumor cells inhibited cell proliferation and mobility through arresting cell cycle and inducing apoptosis. In breast tumor cells, PCDH17 significantly suppressed the active ß-catenin level and its downstream target gene expression. Thus, we found that PCDH17 functions as a tumor suppressor inhibiting Wnt/ß-catenin signaling and metastasis in breast cancer but is frequently methylated in primary tumors which could be a potential biomarker.

miR-7-5p suppresses cell proliferation and induces apoptosis of breast cancer cells mainly by targeting REGγ.

Proteasome activator subunit 3 (REGγ) has a key role in breast cancer by promoting protein proteolysis, but methods to block REGγ expression remain elusive. In this study, we found that the expression of REGγ is significantly upregulated in breast cancer, and that the knockdown of REGγ expression suppresses cell proliferation and induces apoptosis in vitro. Furthermore, REGγ was identified as a direct downstream target of miR-7-5p, and there was an inverse correlation between the expression of REGγ and miR-7-5p. The overexpression of miR-7-5p inhibited cell proliferation and induced apoptosis by mainly targeting REGγ in vitro and in vivo. Our data indicate that miR-7-5p has a critical function through blocking REGγ in breast cancer cells.

OPCML is frequently methylated in human colorectal cancer and its restored expression reverses EMT via downregulation of smad signaling.

Emerging evidence has indicated that the expression of OPCML gene is frequently altered in a variety of cancers. We previously demonstrated that the OPCML gene is a target of epigenetic inactivation and its gene product exhibits tumor-suppressive properties. However, little is known regarding the effects and mechanisms of OPCML in colon cancer. We show that the loss or downregulation of OPCML is associated with its promoter hypermethylation. Methylation of the OPCML promoter was detected in all tumors and tumor-adjacent tissues, but lower methylation in normal colon tissues. The drug-induced release of epigenetic silencing was able to restore OPCML expression and the re-expression led to the suppression of cell growth. Furthermore, the increase in OPCML expression reversed a partial epithelial-to-mesenchymal (EMT)-like transition. Cell migration and invasiveness were also inhibited in response to OPCML upregulation. These actions were mediated through the inactivation of TGFß-Smad signaling pathways. In addition, OPCML expression was associated with two upstream nuclear receptors (ERRa and RORa). Altogether, our study reveals OPCML as a potential tumor suppressor gene epigenetically silenced in colon cancer. Our study will help to elucidate the anti-invasive mechanisms of OPCML and establish new chemotherapeutic strategies for human colon cancer.

Molecular cloning, expression of CPR gene from Rhizopus oryzae into Rhizopus nigericans and its application in the 11α-hydroxylation of 16α, 17-epoxy-progesterone.

The hydroxylations of the steroid skeleton structure are catalyzed by a family of enzymes, the cytochromes P450 (CYPs). In this study, the pCB1004-PgpdA plasmid was used for cloning the cytochrome P450 reductase (CPR) gene from Rhizopus oryzae into Rhizopus nigericans to strengthen the expression of CPR gene in R. nigericans with REMI (Restriction Enzyme Mediate Integration) mediated protoplast transformation. The conditions for the protoplast production of R. nigericans were optimized as follows: 75 µg/mL yatalase, 50 µg/mL lywallzyme, fungus age of 12h, digestion time of 3 h and digestion temperature of 30°C. REMI mediated protoplast transformation with plasmid pCB1004-PgpdA into R. nigericans was performed to construct the transformants. More than 30 transformants were successfully selected from the hygromycin B-resistant plates and 6 transformants had the abilities to improve the biotransformation of 16α, 17-epoxyprogesterone. The highest biotransformation rate of the transformants was 65.38%, which was 7.06% higher than that of the original strain.

Zinc-finger protein 545 inhibits cell proliferation as a tumor suppressor through inducing apoptosis and is disrupted by promoter methylation in breast cancer.

Krüppel-associated box-containing zinc finger proteins (KRAP-ZFPs) are well recognized as key regulators of transcription, which play a crucial role in the regulation of cell proliferation, differentiation, apoptosis and tumorigenesis. We previously identified a KRAP-ZFP protein ZNF545 acting as a tumor suppressor involved in tumor pathogenesis. However, its expression and biological function in breast cancer remain elusive. In this study, we found that ZNF545 was frequently downregulated in estrogen receptor-positive (ER+), progesterone receptor-positive (PR+) and human epidermal growth factor receptor 2-negative (HER2-) breast tumor tissues compared with paired adjacent non-tumor tissues. We further examined its expression and methylation in breast cancer cell lines by semi-quantitative RT-PCR and methylation-specific PCR. We found that ZNF545 was silenced by promoter methylation in MCF7 cell line, and its expression could be restored by demethylation, concomitant with increased unmethylated alleles. ZNF545 methylation was detected in 29% of breast tumor tissues, but not in normal breast tissues, suggesting tumor-specific methylation of ZNF545 in breast cancer. Ectopic expression of ZNF545 in MCF7 cells inhibited cell proliferation through inducing cell cycle G0/G1 arrest and apoptosis, thus as a tumor suppressor. Moreover, ZNF545 upregulated mRNA and protein levels of c-Jun/AP1, BAX, p53 and Caspase 3. Taken together, these results demonstrate that ZNF545 inhibits breast tumor cell proliferation through inducing apoptosis and is disrupted by promoter methylation in breast cancer.