Discrete roles of cytokines, TNF-α, IL-1, IL-6 in tumor promotion and cell transformation

Anti-metastatic Effects of Baicalein by Targeting STAT3 Activity in Breast Cancer Cells

Signal transducer and activator of transcription 3 (STAT3) is considered a potential target for cancer treatment because of its relationship with cellular transformation and tumor initiation and progression. In this study, we aimed to identify a new anti-cancer drug candidate from natural products by targeting STAT3 activity. Using STAT3-luciferase reporter cell line, we screened the chemical library of natural products and found that baicalein, a flavone isolated from the roots of Scutelleria baicalensis, strongly suppressed STAT3 activity in breast cancer cells. Baicalein inhibited STAT3 transcriptional activity and its phosphorylation, and further exhibited anti-proliferative effects in breast cancer cells. Moreover, baicalein suppressed the production of interleukin (IL)-6 and the metastatic potential of breast cancer cells both in vitro and in vivo. Collectively, our study suggests baicalein as an attractive phytochemical compound for reducing metastatic potential of breast cancer cells by regulating STAT3 activity.

High Serum Uric Acid Is Associated with Tubular Damage and Kidney Inflammation in Patients with Type 2 Diabetes

Background

Uric acid presents different roles in an organism. High serum uric acid concentrations may induce inflammatory pathways and promote kidney damage through different mechanisms. Therefore, this study investigated the association among high serum uric acid concentrations, renal tubular damage, and renal inflammation assessed via estimation of urinary kidney injury molecule-1 (KIM-1) and inflammatory cytokines in patients with type 2 diabetes (T2D).

Methods

Urinary concentrations of KIM-1, IL-1, IL-6, IL-10, and TNF-alpha, as well as other biochemical parameters, were assessed in 125 patients with T2D who were grouped into two groups based on the serum uric acid levels (<6.0 mg/dL and ≥6.0 mg/dL). Patients were also stratified according to the tertiles of serum uric acid concentrations.

Results

Urinary KIM-1, IL-1, IL-6, and TNF-alpha were higher in patients with serum uric acid concentrations ≥ 6.0 mg/dL. However, the differences between the groups were not statistically significant when the urinary values of KIM-1 and cytokines were normalized by the urinary creatinine concentration. Serum uric acid concentrations were significantly associated with urinary KIM-1 (values normalized by urinary creatinine concentration) and urinary TNF-alpha (absolute values and values normalized by urinary creatinine concentration), independent of the body mass index (BMI) and estimated glomerular filtration rate (eGFR).

Conclusions

High serum uric acid concentrations were associated with high urinary KIM-1 levels accompanied by the increase of urinary proinflammatory cytokines in patients with T2D. However, normalization of urinary markers by urine creatinine concentration seems to influence the profile of the results.

TCF7L1 promotes skin tumorigenesis independently of β-catenin through induction of LCN2

The transcription factor TCF7L1 is an embryonic stem cell signature gene that is upregulated in multiple aggressive cancer types, but its role in skin tumorigenesis has not yet been defined. Here we document TCF7L1 upregulation in skin squamous cell carcinoma (SCC) and demonstrate that TCF7L1 overexpression increases tumor incidence, tumor multiplicity, and malignant progression in the chemically induced mouse model of skin SCC. Additionally, we show that downregulation of TCF7L1 and its paralogue TCF7L2 reduces tumor growth in a xenograft model of human skin SCC. Using separation-of-function mutants, we show that TCF7L1 promotes tumor growth, enhances cell migration, and overrides oncogenic RAS-induced senescence independently of its interaction with β-catenin. Through transcriptome profiling and combined gain- and loss-of-function studies, we identified LCN2 as a major downstream effector of TCF7L1 that drives tumor growth. Our findings establish a tumor-promoting role for TCF7L1 in skin and elucidate the mechanisms underlying its tumorigenic capacity.

Does triptolide induce lysosomal-mediated apoptosis in human breast cancer cells?

With breast cancer plaguing the United States as the second leading cause of cancer related deaths amongst women, as well as the adverse effects of current treatment options there is a need to develop safer and noninvasive treatments. Triptolide is an extract from the herb Tripterygium wilfordii Hook F, and has been used in Chinese medicine for over two centuries and is now used to treat certain autoimmune diseases, such as rheumatoid arthritis. Based on the anti-proliferative, anti-inflammatory, and anti-cancer properties of triptolide we believe that it will stimulate apoptosis in human breast cancer cells. Triptolide is known to induce apoptosis in many cancer cells lines, but the exact mechanisms that regulate this are largely unknown. It has been suggested that triptolide activates the p53 pathway to trigger apoptosis in these cells. However, we believe that there are other mechanisms at work including the activation of lysosomal-mediated apoptosis.

Prostaglandin E receptor EP3 deficiency modifies tumor outcome in mouse two-stage skin carcinogenesis

We have recently shown that the prostaglandin E(2) (PGE(2)) receptor EP(3) plays an important role in suppression of colon cancer cell proliferation and that its deficiency enhances late stage colon carcinogenesis. Here we examined the effects of EP(3)-deficiency on two-stage skin carcinogenesis. 7,12-Dimethylbenz[a]anthracene (50 microg/200 microl of acetone) was thus applied to the back skin of female EP(3)-knockout and wild-type mice at 8 weeks of age, followed by treatment with 12-O-tetradecanoylphorbol-13-acetate (5 microg/200 microl of acetone) twice a week for 25 weeks. First tumor appearance was observed in EP(3)-knockout mice at week 10, which was 3 weeks later than in EP(3) wild-type mice, and multiplicity observed at week 11 was significantly lower in the EP(3)-knockout case. However, histological examination showed that the tumor incidence and multiplicity at week 25 were not significantly changed in knockout mice and wild-type mice (incidence, 19/19 versus 23/24; multiplicity, 3.58 +/- 0.51 versus 3.17 +/- 0.63, respectively). Interestingly, there were no squamous cell carcinomas (SCCs) in the EP(3)-knockout mice, while SCCs were observed in 3 out of 24 wild-type mice. Furthermore, benign keratoacanthomas only developed in EP(3)-knockout mice (6/19 versus 0/24, P < 0.01). The results suggest that PGE(2) receptor EP(3) signaling might contribute to development of SCCs in the skin.

Production of chemokine CXCL1/KC by okadaic acid through the nuclear factor-kappaB pathway

The murine chemokine CXCL1/KC is known as a chemoattractant for neutrophil infiltration and as a promoter of tumor growth. To determine its relevance in tumorigenesis, we first asked whether okadaic acid (OKA), a natural tumor promoter and a potent protein phosphatase 1 and 2A inhibitor, stimulates KC expression and if it does, through what pathway, in a promotable mouse epidermal-like JB6 cell line commonly used for studying molecules related to tumor promotion. We found that OKA stimulated the de novo synthesis of KC mRNA and protein in a dose- and time-dependent manner. To determine the mechanism by which OKA stimulated the expression of KC at the transcriptional level, transient transfection assays using serially deleted sections of KC promoter fused to luciferase reporter gene were performed. These studies showed that transactivation of KC promoter by OKA specifically involved the region between -104 and -59 containing the two nuclear factor-kappaB (NF-kappaB) response elements (kappaB1 and kappaB2). Further analyses using the mutated NF-kappaB response elements kappaB1 and kappaB2 indicated that both regions were required for optimum transactivation of KC by OKA with the former NF-kappaB response element playing a more significant role in regulating KC expression. Gel-shift and supershift analyses demonstrated the involvement of three NF-kappaB subunits, p65, p50 and c-Rel, with p65 as the major subunit in the NF-kappaB dimer complex. Additionally, immunohistochemistry and western blot analyses confirmed the presence of p65 in the nucleus with its transactivation domain phosphorylated at serine 536. In summary, this is the first report to show that the tumor promoter OKA can stimulate the de novo synthesis and secretion of KC, and that this stimulation is mediated through the NF-kappaB pathway in JB6 cells.