Isochlorogenic Acid C Reverses Epithelial-Mesenchymal Transition via Down-regulation of EGFR Pathway in MDA-MB-231 cells

BACKGROUND/AIM

Epidermal growth factor receptor (EGFR) has been suggested to play an important role in survival, proliferation, migration, differentiation, and tumorigenesis of many cell types. Breast cancer patients with high EGFR expression have a poor prognosis. In this study, we investigated the molecular mechanism of the inhibitory effect of isochlorogenic acid c (ICAC) extracted from Lonicera japonica on elevated EGFR levels of the triple-negative breast cancer (TNBC) cell line, MDA-MB-231.

MATERIALS AND METHODS

The cell viability and cell-cycle analysis were evaluated using 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay and flow cytometry, respectively. The migration ability and invasiveness of ICAC-treated MDA-MB-231 were examined by migration and Matrigel invasion assay. The epithelial-mesenchymal-transition (EMT)-related protein expression was examined by western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

ICAC led to significant morphological changes and suppressed migration and invasion capacities of highly metastatic MDA-MB-231 cells. Western blot analysis for EGFR/EMT-associated proteins suggested that ICAC attenuated the mesenchymal traits as observed by up-regulation of epithelial markers and down-regulation of mesenchymal markers as well as decreased activities of matrix metalloproteinase-9 (MMP-9).

CONCLUSION

These results suggested that the inhibitory effects of ICAC against EGFR-induced EMT and MDA-MB-231 cell invasion were dependent on the EGFR/ phospholipase Cγ (PLCγ)/extracellular regulated protein kinase ½ (ERK½)/slug signaling pathway. Therefore, the obtained results could provide us clues for the next therapeutic strategy in the treatment of TNBC.

MZF-1/Elk-1 interaction domain as therapeutic target for protein kinase Cα-based triple-negative breast cancer cells

Recent reports demonstrate that the expression of protein kinase C alpha (PKCα) in triple-negative breast cancer (TNBC) correlates with decreased survival outcomes. However, off-target effects of targeting PKCα and limited understanding of the signaling mechanisms upstream of PKCα have hampered previous efforts to manipulate this ubiquitous gene. This study shows that the expression of both myeloid zinc finger 1 (MZF-1) and Ets-like protein-1 (Elk-1) correlates with PKCα expression in TNBC. We found that the acidic domain of MZF-1 and the heparin-binding domain of Elk-1 facilitate the heterodimeric interaction between the two genes before the complex formation binds to the PKCα promoter. Blocking the formation of the heterodimer by transfection of MZF-160-72 or Elk-1145-157 peptide fragments at the MZF-1 / Elk-1 interface decreases DNA-binding activity of the MZF-1 / Elk-1 complex at the PKCα promoter. Subsequently, PKCα expression, migration, tumorigenicity, and the epithelial-mesenchymal transition potential of TNBC cells decrease. These subsequent effects are reversed by transfection with full-length PKCα, confirming that the MZF-1/Elk-1 heterodimer is a mediator of PKCα in TNBC cells. These data suggest that the next therapeutic strategy in treating PKCα-related cancer will be developed from blocking MZF-1/Elk-1 interaction through their binding domain.

Amelioration of estrogen-deficiency-induced obesity by Ocimum gratissimum

Objectives: Menopausal transition in women initiates with declining estrogen levels and is followed by significant changes in their physiological characteristics. These changes often lead to medical conditions, such as obesity, which is correlated with chronic low-grade/subclinical inflammation. Ocimum gratissimum L. is a food spice or traditional herb in many countries; the plant is rich in antioxidants, which possess anti-inflammation activities and multitude of other therapeutic functions. Methods: In this study, we evaluated effects of O. gratissimum extract (OGE) in preventing obesity by using ovariectomized (OVX) animal models to mimic menopausal women. Methods: OVX rats showed increase in body weight and in adipocyte size in perigonadal adipose tissue (p <0.05) and decrease in uterus weight. By contrast, OGE (0.2 mg/ml) significantly reduced body weight gain and adipocyte in OVX rats and showed insignificant changes in uterus weight. Further investigation indicated that OGE exerted no influence on levels of dorsal fat, serum total cholesterol, and serum triacylglycerol and on serum biochemical factors, calcium, phosphorus, and glucose. Conclusion: These findings suggested that OGE dietary supplements may be useful in controlling body weight of menopausal women.

Amelioration of estrogen deficiency-induced obesity by collagen hydrolysate

Objectives: Menopausal transition with declining estrogen levels significantly affects the physiological properties of women and consequently contributes to a series of medical conditions, including obesity. Obesity is a crucial risk factor associated with cardiovascular diseases, diabetes mellitus, and breast cancer. Increasing dietary protein content improves satiety and energy expenditure. Thus, we hypothesize that supplementing with collagen, a common dietary protein, may alleviate menopause-induced obesity. Methods: We used ovariectomized (OVX) rats to mimic a menopausal human. The body weight of OVX rats significantly increased compared with that of sham-operated rats (P<0.05), but uterus weight was decreased. Adipocyte size in perigonadal adipose tissue also increased (P<0.05). Results: By contrast, OVX rats supplemented with aqueous collagen hydrolysate (2.5 mg/mL) exhibited significant attenuation in body weight gain and adipocyte enlargement (P<0.05), but insignificant change in uterus weight. Further investigation indicated that collagen hydrolysate supplementation insignificantly affected the levels of dorsal fat, serum total cholesterol, and serum triacylglycerol. Levels of serum biochemical factors, calcium, phosphorus, and glucose were also insignificantly altered by collagen hydrolysate supplementation. Conclusion: Collagen hydrolysate supplementation reduced body weight gain and adipocyte enlargement in response to ovariectomy but slightly affected blood lipids, calcium, and glucose in both sham-operated and OVX rats. Collagen hydrolysate supplementation is beneficial in ameliorating estrogen deficiency-induced obesity and its associated risk factors.

Ocimum gratissmum aqueous extract reduces plasma lipid in hypercholesterol-fed hamsters

Objectives: Hyperlipidemia is a significant risk factor in the development of atherosclerosis and related diseases which are major health problem in many developed and developing countries that can lead to fatality due to the changes in lifestyle and dietary habits in this modern age. Methods: In the present study, the Ocimum gratissimum aqueous extract (OGE) was tested for the lowering effect on the serum lipid level of male hamsters on a high-fat (12%) and high-cholesterol (0.2%) diet (HFCD). Results: The results showed that the levels of serum high-density-lipoprotein-cholesterol (HDL-C) low-density-lipoprotein-cholesterol (LDL-C), total cholesterol (TC), and triglycerols (TG) were increased in the HFCD group (113±11, 259±87, 629±175 and 625±262, respectively), as compared to the control normal diet group (51±8, 19±5, 77±16 and 101±44, respectively). When co-treated with various doses (10 and 20 mg/kg) of the OGE or rosuvastatin, the rats exhibited the restoration of normal serum LDL-C, TC, and TG levels. Conclusion: Therefore, we suggest that the Ocimum gratissimum aqueous extract may have the potential function of lowering serum lipid in rats.

Ocimum gratissimum is Effective in Prevention against Liver Fibrosis in Vivo and in Vitro

Ocimum gratissimum is a traditional herb commonly found in tropical regions, which prevents free radical damage and protects the liver from oxidative stress. In this study, we tested in vivo and in vitro the effectiveness of O. gratissimum extracts (OGEs) in anti-hepatic fibrosis in rats. Male Wistar rats were administered with carbon tetrachloride (CCl4) by intraperitoneal injection and varying amounts of oral injection of OGE doses (0–40 mg/kg body weight) for 8 weeks. Our experiments showed that OGE significantly reduced liver damage, including steatosis and fibrosis, in a dose-dependent manner, as well as significantly decreased the elevation in plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT). It also inhibited the formation of lipid peroxidative products during CCl4 treatment. Moreover, OGE-inhibited CCl4-induced liver collagen accumulation and promoted the expression of catalase, an anti-oxidative enzyme. The inhibition of fibrosis factors α-SMA expression was also observed. In primary cultures, OGE significantly inhibited the serum-induced activation of hepatic stellate cells (HSCs), and the expression of α-SMA and collagen α (I). These data suggest that O. gratissimum possesses anti-hepatic fibrosis properties via its anti-oxidative components.

Resistin-induced stromal cell-derived factor-1 expression through Toll-like receptor 4 and activation of p38 MAPK/ NFκB signaling pathway in gastric cancer cells

BACKGROUND

Stromal cell-derived factor-1 (SDF-1) (CXC chemokine ligand-12)/CXC chemokine receptor 4 (CXCR4) is involved in the carcinogenesis of human gastric cancer, where it stimulates angiogenesis and favors metastasis of tumor cells to distant organs. In addition, resistin is suggested to be an important link between obesity and the development of gastric cancer. Resistin has identified as an important player in inflammatory responses, and emerged as a mediator in inflammation-associated cancer. A limited number of studies have investigated the association of resistin and SDF-1 with gastric cancer. Herein, we investigated the molecular mechanisms by which resistin influences the expression of SDF-1 in gastric carcinoma cells.

RESULTS

Human gastric cancer cell lines were exposed to doses of resistin; SDF-1 expression and secretion levels were then determined. Real-time polymerase chain reaction and western blotting analyses were performed to clarify molecular changes. Inhibition of Toll-like receptor 4 (TLR4) by a competitive antagonist inhibited resistin-induced SDF-1 expression. Pharmacological inhibitors and small interfering RNA (siRNA) demonstrated that activation of the p38 mitogen-activated protein kinase (MAPK) pathway is critical for resistin-induced SDF-1 expression mediated by TLR4. The promoter activity and transcription factor enzyme-linked immunosorbent assay revealed that resistin induced expression of SDF-1 mediated by NF-κB in gastric cancer cells. Inhibition of p38 MARK activation blocked the SDF-1-induced expression and the SDF-1 promoter activity in the cancer gastric cells. Chromatin immunoprecipitation assay revealed that inhibition of p38 MARK activation also blocked the resistin-increased NF-κB-DNA-binding activity.

CONCLUSIONS

Resistin-induced SDF-1 upregulation by activation of TLR4, p38 MARK and NF-κB may explain a new role of resistin in the link of obesity and gastric cancer.

A retrospective analysis of the factors associated with hypercalcaemia in patients with advanced cancer

Hypercalcaemia, a common complication of advanced cancer, causes multiple clinical symptoms, deteriorates patients' quality of life, and is associated with poor prognoses. This study aimed to identify the factors that may be associated with hypercalcaemia in advanced cancer by retrospectively reviewing the medical records of patients (n = 404) admitted to the palliative ward of the Kaohsiung Medical University Hospital, Taiwan, from 2006 to 2008. Patients' demographics, clinical data and symptoms were recorded. Seventy-nine of 404 patients had hypercalcaemia (19.6%), predominant in cases of head-and-neck cancer and haematological malignancies (P < 0.05), but not in those of bone metastases. Hypercalcaemia was associated with consciousness disturbances and leucocytosis (P < 0.05). We recommend that ionised (corrected) calcium levels be monitored clinically in patients with advanced cancer especially when consciousness disturbances are noted, or when head-and-neck or haematological malignancies are present. Testing of free calcium levels is also recommended in patients with leucocytosis.

Adipose-Derived Stem Cells: Isolation, Characterization, and Differentiation Potential

In mammals, the two main types of adipose tissues, white and brown adipose tissues, exert different physiological functions. White adipose tissue (WAT) is for storing energy, while brown adipose tissue (BAT) is for energy consumption. Adipose-derived stem cells (ADSCs) are abundant in WAT and BAT, have multipotent characteristics, and are easily extracted. ADSCs can be differentiated into several cell lineages, including adipocytes, osteoblasts, chondrocytes (cartilage cells), myocytes, and neuronal cells. Therefore, ADSC could be considered as a strategy for future regenerative medicine and tissue engineering.

Expression of protein kinase Cα and the MZF-1 and elk-1 transcription factors in human bladder transitional cell carcinoma cells

In a recent study on hepatocellular carcinoma (HCC), we have shown that the transcription factors Myeloid Zinc Finger-1 (MZF-1) and Ets-like-protein 1 (Elk-1) are significantly related to protein kinase C alpha (PKCα) expression. The purpose of this study was to determine the correlation of the expression of PKCα with the expression of Elk-1 and MZF-1 in various differentiated urinary bladder transitional cell carcinoma (TCC) cell lines: 5637, BFTC905, TSGH8301, HT1376 and HT1197 cells. The malignant potential in the five TCC cell lines was examined by using cell proliferation/migration/invasion assay and the protein and mRNA levels of PKCα, ElK-1 and MZF-1 were examined by Western blot and RT-PCR analysis. The results showed that the rate of cell proliferation in the TSGH8301 cell line was higher than that in other cell lines, while there were obvious signs of cell migration and invasion in 5637, BFTC905 and HT1376 cells, and no sign in TSGH8301 and HT1197 cells. The resulting expression levels of Elk-1 and PKCα were the highest in 5637 cells, but the MZF-1 expression observed in all five cell lines showed no significant difference. To determine whether a correlation exists between PKCα and Elk-1, a shRNA knockout assay was performed and the results showed that the reduction of Elk-1 expression in 5637 cells did not result in the decreased PKCα expression. Therefore, although the findings showed elevated expression of Elk-1 and PKCα in 5637 cells, the regulator of PKCα in bladder cancer cells is yet to be determined.

Expression of protein kinase C α and the MZF-1 and Elk-1 transcription factors in human breast cancer cells

Recently, our research into hepatocellular carcinoma (HCC) has shown that the transcription factors Myeloid Zinc Finger-1 (MZF-1) and Ets-like-protein 1 are related to protein kinase C alpha (PKCα) expression. The purpose of this study was to determine the correlation of the expression of PKCαwith the expressions of Elk-1 and MZF-1 in various differentiated breast cancer cell lines: MDA- MB-231, Hs57BT, SKBR3, MDA-MB-468 and MCF-7. The malignant potential in the five lines of breast cancer cells was examined by using a cell proliferation/migration/invasion assay and the protein and mRNA levels of PKCα, ElK-1 and MZF-1 were examined by Western blot and RT-PCR analysis, re- spectively. The results showed that there were obvious signs of migration and invasion of cells in MDA- MB-231 and Hs57BT cells, little signs of cell migration and invasion in MDA-MB-468 cells, and no sign in SKBR3 and MCF-7 cells. Moreover, the highest expression levels of PKCα, Elk-1 and MZF-1 were also observed in MDA-MB-231 and Hs57BT cells when compared to the other breast cancer cell lines. These findings confirm that elevated expression of PKCαin breast cancer cells may be correlated with the potential of cell migration and invasion, and suggest an association between the expression of PKCα and the expression of the transcription factors Elk-1 and MZF-1.

Can we reduce the cardiovascular risk in peritoneal dialysis patients?

Patients with end-stage renal disease (ESRD), including those treated with peritoneal dialysis (PD), have a high risk for death, particularly from cardiovascular (CV) causes. Traditional risk factors for CV disease – like hypertension, diabetes, and dyslipidemia - are highly prevalent, often severe, and more difficult to treat in dialysis patients. Development of strategies for CV risk reduction in dialysis patients is complicated by epidemiologic studies that demonstrate paradoxical associations of some of the traditional risk factors with mortality. The difficulty is enhanced by either a paucity or negative findings of studies that have tested risk modification by targeting traditional CV risk factors. It is also clear that neither the prevalence nor the severity of traditional risk factors explains the substantial increase in risk for death associated with ESRD; this has led to identification of several nontraditional risk factors. Among these, systemic inflammation, disordered mineral metabolism, and long-term CV risk from infectious complications appear the most promising. However, the evidence in favor of the importance of these risk factors is largely limited to observational studies. In this review, we present a critical analysis of the literature to assist the clinician to reduce the CV risk of ESRD patients treated with PD.

Selective binding of polychlorinated biphenyl congeners by a monoclonal antibody: analysis by kinetic exclusion fluorescence immunoassay

A previously described monoclonal antibody, S2B1, was highly selective for coplanar (non-ortho-chlorinated) PCB congeners in enzyme immunoassays that measured binding at equilibrium. In the present study, kinetic exclusion fluoroimmunoassay (KinExA) was used to determine the dissociation constants (Kd) and on and off rates (k(on), k(off)) for binding of various PCB congeners to affinity-purified S2B1 IgG and Fab fragments in solution. This method revealed that mono- and di-ortho-chlorinated PCBs were bound by S2B1, but the on rates were slower, and the off rates faster by 6-60-fold, than with congeners that had no ortho chlorines. Although the sensitivity of immunoassays may be improved by using competing haptens that S2B1 binds more weakly than the parent PCB, the KinExA results demonstrate that congener specificity is an intrinsic property of S2B1 and does not require weaker binding haptens. KinExA also provided new information on the percentage of active binding sites, valence, and effects of buffer, solvent, and biotinylation on S2B1. The advantages and drawbacks of KinExA for measuring antibody-ligand binding are described.

Derivation and properties of recombinant Fab antibodies to coplanar polychlorinated biphenyls

Recombinant Fab antibodies (rFabs) specific for coplanar polychlorinated biphenyls (PCBs) were derived from a hybridoma cell line (Chiu et al. Anal. Chem. 1995, 67, 3829-3839). Immunoglobulin V(H)-C(H1) and V(L)-C(L) sequences from S2B1 messenger RNA were amplified by PCR and cloned into the M13 phagemid vector pComb3H. Phage displaying rFab were enriched by panning on a PCB hapten conjugate and expressed as soluble rFabs in Escherichia coli XL-1 Blue. Two rFab clones competitively bound PCBs 77 and 126 with half-maximal inhibition (I(50)) of 10-13 ppb in indirect and direct enzyme immunoassays (EIAs), with selectivity nearly identical to that of whole S2B1 IgG and its Fab fragments prepared by papain digestion. These results, and comparison of N-terminal amino acid sequences of MAb S2B1 and the rFab, indicated that rFab S2B1 is a functional copy of the MAb. The rFab S2B1 sequences have 75-89% sequence identity with antibodies that bind nitrophenyl haptens and are being used to construct a three-dimensional computational model of the PCB binding site.

A monoclonal immunoassay for the coplanar polychlorinated biphenyls

Polychlorinated biphenyls (PCBs) are ubiquitous environmental pollutants with diverse toxic, teratogenic, reproductive, immunotoxic, and tumorigenic effects. Three of the least abundant of the 209 PCB isomers (congeners) are the most toxic and most difficult to quantify. These are 3,4,3',4'-tetrachlorobiphenyl, 3,4,3',4',5'-pentachlorobiphenyl, and 3,4,5,3',4',5'-hexachlorobiphenyl (IU-PAC No. 77, 126, and 169, respectively). An immunizing hapten was designed to retain the 3,4,3',4' chlorine-substitution pattern and coplanarity characteristic of these toxic congeners. The optimal competitors for immunoassay were weaker binding distinctive single-ring fragments of the PCBs. A monoclonal antibody designated S2B1 was derived and used in direct (antibody-capture) competitive enzyme immunoassays (EIAs). The EIAs are highly specific for non-ortho-substituted congeners and do not recognize the more prevalent but much less toxic noncoplanar PCB congeners or 2,3,7,8-tetrachlorodibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzofuran, or dichlorobenzenes. Hapten and competitor design for this assay suggests a basis for development of sensitive EIAs for other classes of PCB congeners.

Blood content in guinea-pig tissues: correction for the study of drug tissue distribution

The blood content in different organs or tissues of guinea-pigs was determined by means of [125I]bovine serum albumin. The blood distribution expressed as percentage of total body blood for various organs or tissues ranged from 0.35 (adipose) to 17.5 (muscle)%. The blood content in tissue preparations expressed as the blood background correction factor, F (ml blood/g wet tissue) depended on the extent of bleeding during experiment; that factor can cause a considerable difference in the results of a tissue distribution study of a drug. Blood content was high in the lung (0.36 ml/g), heart, liver, kidney and spleen, but low in adipose and brain tissues (0.021 ml/g). The distribution of valproic acid in various tissues of guinea-pigs after intravenous injection was determined from the homogenates of isolated organs. The results showed that blood contamination can greatly alter the data of tissue distribution of a drug to as much as 25%. This study proposed a maximum (non-bled) and a minimum (extreme-bled) blood background correction factor for respective tissues of guinea-pigs, as well as equations for correcting the blood contamination in tissue during the drug distribution study. The results suggest that to obtain an exact analysis of drug concentrations in specific tissues, a correction for the blood of that specific tissue is necessary.