Dynamic interactions of lactic acid bacteria in Korean sourdough during back-slopping process

AIMS

This study aimed to clarify the cause of quality reduction in Korean sourdough after successive back-slopping.

METHODS AND RESULTS

We investigated the dynamic changes in lactic acid bacteria during the back-slopping process using genetic fingerprinting techniques. During the initial propagation phases, the dominant lactic acid bacteria were Fructilactobacillus sanfranciscensis (<5 log CFU per g sourdough), Latilactobacillus curvatus (9·5 log CFU per g sourdough) and Levilactobacillus brevis (6·5 log CFU per g sourdough). However, after the 11th propagation, F. sanfranciscensis became more prominent (>9·0 log CFU per g sourdough), whereas L. curvatus and L. brevis rapidly decreased. Monitoring these bacteria in the co-culture system revealed that acid-tolerant F. sanfranciscensis rapidly utilized maltose (1·65 g l^-1  h^-1 ) and produced large amounts of lactic acid, whereas L. brevis and L. curvatus consumed maltose slowly and L. curvatus was poorly tolerant to lactic acid.

CONCLUSION

The results indicate that competition exists between the lactic acid bacteria in sourdough during the back-slopping process, and microbial succession by acid-tolerant species results in quality reduction of sourdough.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study uncovered the cause of microbial changes during the propagation of Korean sourdough and proposed a strategy to develop starters to produce high-quality bakery products.

Selective inhibition of CDK4/6: A safe and effective strategy for developing anticancer drugs

The sustained cell proliferation resulting from dysregulation of the cell cycle and activation of cyclin-dependent kinases (CDKs) is a hallmark of cancer. The inhibition of CDKs is a highly promising and attractive strategy for the development of anticancer drugs. In particular, third-generation CDK inhibitors can selectively inhibit CDK4/6 and regulate the cell cycle by suppressing the G1 to S phase transition, exhibiting a perfect balance between anticancer efficacy and general toxicity. To date, three selective CDK4/6 inhibitors have received approval from the U.S. Food and Drug Administration (FDA), and 15 CDK4/6 inhibitors are in clinical trials for the treatment of cancers. In this perspective, we discuss the crucial roles of CDK4/6 in regulating the cell cycle and cancer cells, analyze the rationale for selectively inhibiting CDK4/6 for cancer treatment, review the latest advances in highly selective CDK4/6 inhibitors with different chemical scaffolds, explain the mechanisms associated with CDK4/6 inhibitor resistance and describe solutions to overcome this issue, and briefly introduce proteolysis targeting chimera (PROTAC), a new and revolutionary technique used to degrade CDK4/6.

Sodium cantharidinate, a novel anti-pancreatic cancer agent that activates functional p53

Despite the use of many types of chemotherapies for pancreatic cancer, optimal efficacy has not been obtained so far. Pancreatic cancer shows a high incidence of TP53 mutations, inactivating its tumor suppressor activity. In this study, we identified sodium cantharidinate as a novel, potential anti-pancreatic cancer agent that activates p53 function. Sodium cantharidinate reduced the viability of pancreatic cancer cells, including the human primary pancreatic cancer cells, PANC-1, AsPC-1, SW1990 and BXPC-3, in a dose-dependent manner. Sodium cantharidinate induced apoptosis and DNA damage of pancreatic cancer cells. Furthermore, proteome-wide sequencing analysis detected a marked perturbation in p53 signaling pathway on PANC-1 cells upon sodium cantharidinate. Consistent with the previous results, sodium cantharidinate treatment decreased Bcl-2 and mitochondrial cytochrome-c protein expression, as well as phosphorylation of MDM2; meanwhile, it increased the levels of cleaved-caspase-3, cleaved-caspase-9, cleaved-PARP, Bax, and phosphorylated p53, thus inducing the apoptosis of pancreatic cancer cells. The p53-activating effect of sodium cantharidinate was strongly abrogated by treatment with TP53-targeting shRNA. Moreover, sodium cantharidinate inhibited neoplasm growth via the JAK2-STAT3 pathway, which was inhibited by shRNA-TP53 and triggered by combination with gemcitabine. Combination therapy indicated that sodium cantharidinate and gemcitabine synergistically reduced ex vivo and in vivo growth of pancreatic neoplasm. Further docking studies revealed the different binding fates of sodium cantharidinate to activate wild-type p53 function. Thus, sodium cantharidinate could be a potential agent with promising anti-pancreatic cancer efficacy.

Lead discovery, chemical optimization, and biological evaluation studies of novel histone methyltransferase SET7 small-molecule inhibitors

The post-translational modifications of histones, including histone methylation and demethylation, control the expression switch of multiple genes. SET domain-containing lysine methyltransferase 7 (SET7) is the only methyltransferase, which can specifically monomethylate lysine-4 of histone H3 (H3K4me1) and play critical roles in various diseases, including breast cancer, hepatitis C virus (HCV), atherosclerotic vascular disease, diabetes, prostate cancer, hepatocellular carcinoma, and obesity. However, several known SET7 inhibitors exhibit weak activity or poor selectivity. Therefore, the development of novel SET7 inhibitors is highly desirable and of great clinical value. In this study, we identified 2-79 as a new hit compound by structure-based virtual screening and further AlphaLISA-based biochemical evaluation. Via chemical optimization, the synthesized compound DC21 was confirmed as a potent SET7 inhibitor with an IC₅₀ value of 15.93 μM. The interaction between DC21 and SET7 was also validated through SPR experiment. Especially, DC21 retarded proliferation of MCF7 cells with an IC₅₀ value of 25.84 μM in cellular level. In addition, DC21 has good selectivity for several other epigenetic targets, such as SUV39H1, G9a, NSD1, DOT1L and MOF. DC21 can serve as a lead compound to develop more potential SET7 inhibitors and as a chemical probe for SET7 biological function studies.

Comparison of elapegademase and pegademase in ADA-deficient patients and mice

The absence of adenosine deaminase (ADA) causes severe combined immune deficiency (SCID), which has been treated with PEGylated bovine-extracted ADA (ADAGEN). ADAGEN was recently replaced by a PEGylated recombinant bovine ADA, expressed in Escherichia coli (elapegademase, ELA-ADA). Limited information on ELA-ADA is available.  ADA enzymatic activity of ELA-ADA and ADAGEN was assessed in vitro at diverse dilutions. ADA activity and immune reconstitution in an ADA-SCID patient treated with ELA-ADA were compared with age-matched patients previously treated with ADAGEN. ADA activity and thymus reconstitution were evaluated in ADA-deficient mice following ELA-ADA or ADAGEN administered from 7 days postpartum. In vitro, ADA activity of ELA-ADA and ADAGEN were similar at all dilutions. In an ADA-SCID patient, ELA-ADA treatment led to a marked increase in trough plasma ADA activity, which was 20% higher than in a patient previously treated with ADAGEN. A marked increase in T cell numbers and generation of naive T cells was evident following 3 months of ELA-ADA treatment, while T cell numbers increased following 4 months in 3 patients previously treated with ADAGEN. T cell proliferations stimulation normalized and thymus shadow became evident following ELA-ADA treatment. ADA activity was significantly increased in the blood of ADA-deficient mice following ELA-ADA compared to ADAGEN, while both treatments improved the mice weights, the weight, number of cells in their thymus and thymocyte subpopulations. ELA-ADA has similar in- vitro and possibly better in-vivo activity than ADAGEN. Future studies will determine whether ELA-ADA results in improved long-term immune reconstitution.

Expression and significance of SATB1 in the development of breast cancer

Special AT-rich sequence binding protein 1 (SATB1) is a recently discovered gene regulator that can promote the growth and metastasis of breast cancer. However, its expression in different stages of breast cancer development have not been examined. We explored the role of SATB1 in the development of breast cancer by detecting SATB1 expression levels in different stages of breast cancer. SATB1 expression was determined using an immunohistochemical streptavidin peroxidase method; the relationship between clinicopathological features of breast cancer and SATB1 expression was analyzed using the X(2) test. Positive rates of SATB1 protein in normal breast tissue, normal breast ductal hyperplasia tissue, precancerous lesions of breast cancer, non-invasive cancer, early invasive carcinoma, and invasive breast cancer tissue were, respectively, 6.25 (2/32), 6.4 (3/47), 20.4 (10/49), 45.0 (9/20), 52.9 (9/17), and 76.6% (72/94). SATB1 in the latter 3 groups was significantly higher than in the first 3 groups (P < 0.05). The positive rate of SATB1 protein in invasive non-special types of breast cancer (88.5%, 54/61) was significantly higher than in the special type of invasive breast cancer (54.5%, 18/33) and early invasive breast cancer (52.9%, 9/17) (P < 0.05). SATB1 protein expression in breast cancer with lymph node metastasis was generally increased, and the difference was statistically significant (P < 0.05). SATB1 protein expression showed an increasing trend in different stages of breast cancer development. Overexpression indicated poor prognosis.

Development and characterization of mouse monoclonal antibodies reactive with chicken IL-1β

Interleukin-1β proteins from chicken, duck, goose, turkey, and pigeon share 77 to 99% amino acid sequence similarity among themselves, and only 31 to 35% sequence similarity is shared between avian and mammalian IL-1β. There have been no antibodies that specifically detect avian IL-1β, and the current study was conducted to develop mouse monoclonal antibodies (mAb) against chicken IL-1β (chIL-1β) to further define its biochemical and immunological properties. In this study, 2 mouse mAb that are specific for chIL-1β were produced and characterized. Both mAb identified a 66.0 kDa recombinant chIL-1β protein expressed in Escherichia coli by Western blot analysis that corresponded to the expected molecular weight of a recombinant fusion protein containing the full-length 23.0 kDa chIL-1β protein and a 43.0 kDa maltose binding protein tag. Immunohistochemical analysis identified cells producing endogenous chIL-1β in the cecal tonsils, bursa of Fabricius, and spleen. Purified recombinant chIL-1β dose-dependently stimulated the proliferation and nitric oxide production by thymocytes, and both activities were inhibited by co-incubation with the 2 chIL-1β mAb described in this paper. These mAb will be important immune reagents for basic and applied poultry research of IL-1β in poultry.

The role of DAB2IP in androgen receptor activation during prostate cancer progression

Altered androgen-receptor (AR) expression and/or constitutively active AR are commonly associated with prostate cancer (PCa) progression. Targeting AR remains a focal point for designing new strategy of PCa therapy. Here, we have shown that DAB2IP, a novel tumor suppressor in PCa, can inhibit AR-mediated cell growth and gene activation in PCa cells via distinct mechanisms. DAB2IP inhibits the genomic pathway by preventing AR nuclear translocation or phosphorylation and suppresses the non-genomic pathway via its unique functional domain to inactivate c-Src. Also, DAB2IP is capable of suppressing AR activation in an androgen-independent manner. In addition, DAB2IP can inhibit several AR splice variants showing constitutive activity in PCa cells. In DAB2IP(-/-) mice, the prostate gland exhibits hyperplastic epithelia, in which AR becomes more active. Consistently, DAB2IP expression inversely correlates with AR activation status particularly in recurrent or metastatic PCa patients. Taken together, DAB2IP is a unique intrinsic AR modulator in normal cells, and likely can be further developed into a therapeutic agent for PCa.

Targeted gene silencing of TLR4 using liposomal nanoparticles for preventing liver ischemia reperfusion injury

RNAi-based therapy is a promising strategy for the prevention of ischemia-reperfusion injury (IRI). However, systemic administration of small interfering RNA (siRNA) may cause globally nonspecific targeting of all tissues, which impedes clinical use. Here we report a hepatocyte-specific delivery system for the treatment of liver IRI, using galactose-conjugated liposome nanoparticles (Gal-LipoNP). Heptocyte-specific targeting was validated by selective in vivo delivery as observed by increased Gal-LipoNP accumulation and gene silencing in the liver. Gal-LipoNP TLR4 siRNA treatment resulted in a significant decrease of serum alanine transferase (ALT) and aspartate transaminase (AST) in a hepatic IRI model. Histopathology displayed an overall reduction of the injury area in the Gal-LipoNP TLR4 siRNA treated mice. Additionally, neutrophil accumulation and lipid peroxidase-mediated tissue injury, detected by MPO, MDA and ROS respectively, were attenuated after Gal-LipoNP TLR4 siRNA treatment. Moreover, therapeutic effects of Gal-LipoNP TLR4 siRNA were associated with suppression of the inflammatory cytokines IL-1 and TNF-α. Taken together, this study is the first demonstration of liver IRI treatment using liver-specific siRNA delivery.

Abstract P3-01-03: The Predictive Value of Serum Serum Her-2/neu for Response to Anthracycline-Based and Trastuzumab-Based Neoadjuvant Chemotherapy of Advanced Primary Breast Cancer

Background:There excists little information about a possible influence of serum Her-2/neu on response to chemotherapy. We aimed that the assessment of serum Her-2/neu in pretreatment serum sample can be useful in predicting response to neoadjuvant chemotherapy. Methods: All breast cancers were tested by immunohistochemical stain and FISH for Her-2/neu before treatment. Serum Her-2/neu was twice measured by Chemiluminescence immunoassay (ADVIA centaur®TMsystem) before neoadjuvant chemotherapy and before operation. The cutoff value was 10.2 mg/ml according to previous study. Pathologic complete response (pCR) was considered as no residual tumor or remnant ductal carcinoma in situ, partial response (PR) was less than 50% decrease in maximal diameter in pathologic tumor size.The measurements for the change of serum Her-2/neu were defined as pretreatment Her-2/neu — preoperation Her-2/neu. We compared the change of serum Her-2/neu between 1) before prechemotherapy and after chemotherapy 2) pathologic complete response and partial response 3) trastuzumab (H) group and anthracyline (A) group. Results: Serum Her-2/neu was decreased after neoadjuvant chemotherapy. Mean of serum Her-2/neu in prechemotherapy was 15.4±9.0 ng/mL, that of postchemotherapy was 10.5± 2.0 ng/mL (p= 0.04). Pathologic response was correlated with the change of serum Her-2/neu (PR: 6.1 ng/ml vs. pCR: 42.0 ng/ml, p= 0.014). Serum Her-2/neu of trastuzumab group was more decreased than of anthracyline group (H=12.9 ± 14.5 ng/mL ; A= 2.2 ± 1.2 ng/mL; p=0.024). In trastuzumab group, pCR was boreline significantly correlated with change of serum Her-2/neu (PR: 0.8 ± 0.84 ng/ml vs. pCR: 21.1 ± 13.2 ng/ml, p= 0.08). Conclusions: Prechemotherapy serum Her-2/neu was to be a significant predictor of pathologic response to neoadjuvant chemotherapy. Serum Her-2/neu levels during treatment were associated with pathologic response in patients receiving neoadjuvant chemotherapy, particularly, in trastuzumab-based regimen. Serum Her-2/neu levels may serve to monitoring neoadjuvant therapy in Her-2/neu overexpressed breast cancer.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-01-03.