Zhongbo Liu

The Wnt inhibitory factor 1 restoration in prostate cancer cells was associated with reduced tumor growth, decreased capacity of cell migration and invasion and a reversal of epithelial to mesenchymal transition

BackgroundAberrations in the Wnt pathway have been reported to be involved in the metastasis of prostate cancer (PCa) to bone. We investigated the effect and underlying mechanism of a naturally-occurring Wnt inhibitor, WIF1, on the growth and cellular invasiveness of a bone metastatic PCa cell line, PC3.ResultsThe WIF1 gene promoter was hypermethylated and its expression down-regulated in the majority (7 of 8) of PCa cell lines. Restoration of WIF1 expression in PC-3 cells resulted in a decreased cell motility and invasiveness via up-regulation of epithelial markers (E-cadherin, Keratin-8 and-18), down-regulation of mesenchymal markers (N-cadherin, Fibronectin and Vimentin) and decreased activity of MMP-2 and -9. PC3 cells transfected with WIF1 consistently demonstrated reduced expression of Epithelial-to-Mesenchymal Transition (EMT) transcription factors, Slug and Twist, and a change in morphology from mesenchymal to epithelial. Moreover, WIF1 expression significantly reduced tumor growth by approximately 63% in a xenograft mouse model. This was accompanied by an increased expression of E-cadherin and Keratin-18 and a decreased expression of vimentin in tumor tissues.ConclusionThese data suggest that WIF1 regulates tumor invasion through EMT process and thus, may play an important role in controlling metastatic disease in PCa patients. Blocking Wnt signaling in PCa by WIF1 may represent a novel strategy in the future to reduce metastatic disease burden in PCa patients.

Flavokawain B, a kava chalcone, induces apoptosis via up-regulation of death-receptor 5 and Bim expression in androgen receptor negative, hormonal refractory prostate cancer cell lines and reduces tumor growth.

Limited success has been achieved in extending the survival of patients with metastatic and hormone‐refractory prostate cancer (HRPC). There is a strong need for novel agents in the treatment and prevention of HRPC. We have shown that flavokawain B (FKB), a kava chalcone, is about 4‐ to 12‐fold more effective in reducing the cell viabilities of androgen receptor (AR)‐negative, HRPC cell lines DU145 and PC‐3 than AR‐positive, hormone‐sensitive prostate cancer cell lines LAPC4 and LNCaP, with minimal effect on normal prostatic epithelial and stromal cells. FKB induces apoptosis with an associated increased expression of proapoptotic proteins: death receptor‐5, Bim and Puma and a decreased expression of inhibitors of apoptosis protein: XIAP and survivin. Among them, Bim expression was significantly induced by FKB as early as 4 hr of the treatment. Knockdown of Bim expression by short‐hairpin RNAs attenuates the inhibitory effect on anchorage‐dependent and ‐independent growth and caspase cleavages induced by FKB. These findings suggest that the effect of FKB, at least in part, requires Bim expression. In addition, FKB synergizes with TRAIL for markedly enhanced induction of apoptosis. Furthermore, FKB treatment of mice bearing DU145 xenograft tumors results in tumor growth inhibition and increases Bim expression in tumor tissues. Together, these results suggest robust mechanisms for FKB induction of apoptosis preferentially for HRPC and the potential usefulness of FKB for prevention and treatment of HRPC in an adjuvant setting.

Rhodiola rosea extracts and salidroside decrease the growth of bladder cancer cell lines via inhibition of the mTOR pathway and induction of autophagy

The incidence of human urinary bladder cancer increases markedly with age, suggesting a mechanistic connection between aging and bladder carcinogenesis and a potential use of anti‐aging agents in bladder cancer chemoprevention. Rhodiola rosea, growing in high altitude or cold regions of the world, has been reported to have anti‐aging effects in Drosophila. We demonstrated that a R. rosea extract and one of its bioactive components, salidroside, inhibited the growth of bladder cancer cell lines with a minimal effect on nonmalignant bladder epithelial cells TEU‐2. Interestingly, the R. rosea extract and salidroside component exhibited a selective ability to inhibit the growth of p53 knockout primary mouse embryo fibroblasts (p53−/− MEFs) compared to their wild‐type counterparts. The growth inhibitory effects of the R. rosea extract and salidroside were, however, attenuated in TSC2 and p53 double knock MEFs (TSC2−/−, p53−/− MEFs), suggesting that TSC2 protein is, at least in part, required for the growth inhibitory effects of the R. rosea extract and salidroside. The R. rosea extract and salidroside treatment of UMUC3 cells resulted in an increase of AMP‐activated protein kinase (AMPK)‐α phosphorylation and a decrease of 4E‐BP1 phosphorylation, leading to increased binding of 4E‐BP1 to m7 GTP. These results indicate that the R. rosea extract and salidroside inhibit translation initiation. Furthermore, both the R. rosea extract and salidroside treatment of UMUC3 cells caused a significant percentage of cells undergoing autophagy. Therefore, the R. rosea extract and salidroside deserve further study as novel agents for chemoprevention of bladder carcinogenesis.

Kava Components Down-Regulate Expression of AR and AR Splice Variants and Reduce Growth in Patient-Derived Prostate Cancer Xenografts in Mice

Men living in Fiji and drinking kava have low incidence of prostate cancer (PCa). However, the PCa incidence among Fijian men who had migrated to Australia, increased by 5.1-fold. We therefore examined the potential effects of kava root extracts and its active components (kavalactones and flavokawains) on PCa growth and androgen receptor (AR) expression. PCa cell lines (LNCaP, LAPC-4, 22Rv1, C4-2B, DU145 and PC-3) with different AR expression, and a transformed prostate myofibroblast cell line (WPMY-1), were treated with a commercial kava extract, kavalactones (kawain, 5′6′-dehydrokawain, yangonin, methysticin) and flavokawain B. Expression of AR and its target genes (PSA and TMPRSS2) was examined. Two novel patient-derived PCa xenograft models from high grade PCa specimens were established by implanting the specimens into nude mice and passing tumor pieces through subcutaneous injection in nude mice, and then treated with kava extract and flavokawain B to examine their effects on tumor growth, AR expression and serum PSA levels. The kava extract and flavokawain B effectively down-regulated the expression of both the full-length AR and AR splice variants. The kava extract and kavalactones accelerated AR protein degradation, while flavokawain B inhibited AR mRNA transcription via decreasing Sp1 expression and the binding of Sp1 to the AR promoter. The kava root extract and flavokawain B reduce tumor growth, AR expression in tumor tissues and levels of serum PSA in the patient-derived PCa xenograft models. These results suggest a potential usefulness of a safe kava product or its active components for prevention and treatment of advanced PCa by targeting AR.

The Effect of Gartanin, a Naturally Occurring Xanthone in Mangosteen Juice, on the mTOR Pathway, Autophagy, Apoptosis, and the Growth of Human Urinary Bladder Cancer Cell Lines

Garcinia mangostana, often referred to as mangosteen, is a fruit grown in Southeast Asia and has been used for centuries as a local beverage and natural medicine. Its bioactive compounds, xanthones (i.e., gartanin, α-mangostin, etc), have reported effects on ailments ranging from skin infections and inflammation to urinary tract infections. We demonstrate that mangosteen xanthones (i.e., gartanin and α-mangostin) at pharmacologically achievable concentrations inhibit the growth of cancer cell lines from different stages of human urinary bladder cancer. The growth inhibitory effects of gartanin in mouse embryonic fibroblasts are at least in part dependent on the existence of p53 or TSC1. Indeed, further studies have shown that gartanin treatment of bladder cancer cell lines T24 and RT4 resulted in a marked suppression of p70S6 and 4E-BP1 expression and induction of autophagy, suggesting the inhibition of the mTOR pathway. In addition, gartanin downregulated the expression of Bcl-2 and activated the p53 pathway leading to apoptosis induction. Together, these results suggested that gartanin is a multiple targeting agent that is suitable for further study into its chemopreventive properties for human urinary bladder cancer.

KAVA chalcone, Flavokawain A, inhibits urothelial tumorigenesis in the UPII-SV40T transgenic mouse model

Flavokawain A (FKA) is the predominant chalcone identified from the kava plant. We have previously shown that FKA preferentially inhibits the growth of p53 defective bladder cancer cell lines. Here, we examined whether FKA could inhibit bladder cancer development and progression in vivo in the UPII-SV40T transgenic model that resembles human urothelial cell carcinoma (UCC) with defects in the p53 and the retinoblastoma (Rb) protein pathways. Genotyped UPII-SV40T mice were fed orally with vehicle control (AIN-93M) or FKA (6 g/kg food; 0.6%) for 318 days starting at 28 days of age. More than 64% of the male mice fed with FKA-containing food survived beyond 318 days of age, whereas only about 38% of the male mice fed with vehicle control food survived to that age (P = 0.0383). The mean bladder weights of surviving male transgenic mice with the control diet versus the FKA diet were 234.6 ± 72.5 versus 96.1 ± 69.4 mg (P = 0.0002). FKA was excreted primarily through the urinary tract and concentrated in the urine up to 8.4 μmol/L, averaging about 38 times (males) and 15 times (females) more concentrated than in the plasma (P = 0.0001). FKA treatment inhibited the occurrence of high-grade papillary UCC, a precursor to invasive urothelial cancer, by 42.1%. A decreased expression of Ki67, survivin, and X-linked inhibitor of apoptotic proteins (XIAP) and increased expression of p27 and DR5, and the number of terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling (TUNEL)-positive apoptotic cells were observed in the urothelial tissue of FKA-fed mice. These results suggest a potential of FKA in preventing the recurrence and progression of non–muscle-invasive UCC. Cancer Prev Res; 6(12); 1365–75. ©2013 AACR.

Dietary feeding of flavokawain A, a Kava chalcone, exhibits a satisfactory safety profile and its association with enhancement of phase II enzymes in mice

Flavokawain A (FKA), a major chalcone in the Kava plant, has recently demonstrated promising anti-cancer activities. A systematic evaluation of FKAs safety profile has not been reported before. In this study, male FVB/N mice were fed with an AIN-76A diet or AIN-76A diet supplemented with 0.6% (6 g/kg food) FKA or 0.6% commercial kava root extract (KRE) for three weeks. Dietary feeding of FKA did not affect food consumption and body weight. Histopathological examination of liver, kidney, colon, lung, heart, spleen, and thymus revealed no signs of FKA-induced toxicity. Biochemical serum analysis and histological examination confirmed normal organ function in FKA-treated mice. The cytotoxicity profile showed FKA had minimal side effects on bone marrow and small intestinal epithelial cells compared with Adriamycin. In addition, oral feeding of FKA increased activities of both glutathione S-transferase and quinone reductase in the liver, lung, prostate and bladder tissues of mice. In comparison, dietary feeding of 0.6% KRE increased liver/body weight ratio and decreased spleen, thymus, and testis/body weight ratios, as well as induced nodular proliferation in liver tissues. Therefore, dietary feeding FKA showed no adverse effects on major organ function and homeostasis in mice, suggesting the potential of FKA for chemoprevention study of human cancers.

High Sensitivity of an Ha-RAS Transgenic Model of Superficial Bladder Cancer to Metformin Is Associated with ∼240-Fold Higher Drug Concentration in Urine than Serum

While pharmacoepidemiologic and laboratory studies have supported the hypothesis that the antidiabetic drug metformin may be useful in treating or preventing cancer, there is limited evidence to suggest which specific cancer sites may be particularly sensitive. Sensitivity likely is determined both by features of tumor pathophysiology and by pharmacokinetic factors. We used UPII-mutant Ha-ras transgenic mice that develop hyperplasia and low-grade, papillary urothelial cell carcinoma to determine whether metformin has activity in a model of superficial bladder cancer. Metformin significantly improved survival, reduced urinary tract obstruction, reduced bladder weight (a surrogate for tumor volume), and led to clear activation of AMP α kinase and inhibition of mTOR signaling in neoplastic tissue. We investigated the basis of the unusual sensitivity of this model to metformin, and observed that following oral dosing, urothelium is exposed to drug concentrations via the urine that are approximately 240-fold higher than those in the circulation. In addition, we observed that bladder cancer cell lines (RT4, UMUC-3, and J82) with homozygous deletion of either TSC1 or PTEN are more sensitive to metformin than those (TEU2, TCCSUP, and HT1376) with wild-type TSC1 and PTEN genes. Our findings provide a strong rationale for clinical trials of oral metformin in treatment of superficial bladder cancer. Mol Cancer Ther; 15(3); 430–8. ©2016 AACR.

Aerosol transfer of bladder urothelial and smooth muscle cells onto demucosalized colonic segments for bladder augmentation: in vivo, long term, and functional pilot study.

BACKGROUND Bladder augmentation technique has changed over the years and the current practice has significant adverse health effects and long-term sequelae. Previously, we reported a novel cell transfer technology for covering demucosalized colonic segments with bladder urothelium and smooth muscle cells through an aerosol spraying of these cells and a fibrin glue mixture. OBJECTIVE To determine the long-term durability and functional characteristics of demucosalized segments of colon repopulated with urothelial cells in the bladder of swine for use in augmentation cystoplasty. STUDY DESIGN Nine swine were divided into three groups. The first group (control) underwent standard colocystoplasty; the second group underwent colocystoplasty with colonic demucosalization and aerosol application of fibrin glue and urothelial cell mixture; in the third group detrusor cells were added to the mixture described in group two. The animals were kept for 6 months. Absorptive and secretory function was assessed. Bladders were harvested for histological and immunohistochemical evaluation. RESULTS All animals but one in the experimental groups showed confluent urothelial coverage of the colonic segment in the bladder without any evidence of fibrosis, inflammation, or regrowth of colonic epithelial cells. Ten percent of the instilled water in the bladder was absorbed within an hour in the control group, but none in experimental groups(p = 0.02). The total urine sediment and protein contents were higher in the control group compared with experimental groups (p < 0.05). DISCUSSION Both study groups developed a uniform urothelial lining. Histologically, the group with smooth muscle had an added layer of submucosal smooth muscle. Six months after bladder augmentation the new lining was durable. We were also able to demonstrate that the reconstituted augmented segments secrete and absorb significantly less than the control colocystoplasty group. We used a non-validated simple method to evaluate permeability of the new urothelial lining to water. To determine if the aerosol transfer of bladder cells would have behaved differently in the neurogenic bladder population, this experiment should have been performed in animals with neuropathic bladders. CONCLUSION Aerosol spraying of single cell suspension of urothelial and muscular cells with fibrin glue resulted in coverage of the demucosalized intestinal segment with a uniform urothelial layer. This new lining segment was durable without regrowth of colonic mucosa after 6 months. The new reconstituted segment absorbs and secretes significantly less than control colocystoplasty.

Abstract 618: Rhodiola rosea L. extract, SHR-5, and metformin exhibit potent activity against bladder carcinogenesis in the UPII-mutant Ha-ras transgenic model.

The incidence of human urinary bladder cancer increases markedly with age, suggesting a mechanistic connection between aging and bladder carcinogenesis and a potential use of anti-aging agents in bladder cancer chemoprevention. Rhodiola rosea, growing in high altitude or cold regions of the world, has been reported to have anti-aging effects in Drosophila. Metformin, a popular anti-diabetics drug, has also shown anti-aging effect in mice. In addition, both agents have been shown to inhibit the mTOR pathway. Therefore, we examined the effect of SHR-5 and Metformin on bladder carcinogenesis in the UPII-mutant Ha-ras transgenic mouse bladder model. This model mimics human papillary transitional cell carcinoma and exhibits enhanced mTOR activity in the bladder tumors. The homozygous mutant Ha-ras transgenic mice were identified through genotyping using Southern blotting analysis. 0.625% SHR-5 or 0.1% Metformin in drinking water was given to the mice starting at 6 weeks of age and ending at 6 months of age. About 42% of homozygous mutant Ha-ras male transgenic mice which drank normal water died of urinary tract obstruction and hydronephrosis within 6 months of age, while more than 93% and 89% of mice which drank SHR-5 or Metformin containing water survived. The mean bladder weights in male mice drinking SHR-5 or Metformin decreased by 69% and 62%, respectively, compared to control group (Bladder weights for mice drinking normal water versus SHR-5 or Metformin are 0.3382± 0.061versus 0.1278± 0.02 or 0.1053±0.015 gram, P=0.0197 or 0.0082). The mean bladder weights in female mice which drank SHR-5 or Metformin containing water also decreased by about 40% or 39.8 %, respectively, compared to those which drank normal water (Bladder weights for normal water versus SHR-5 or Metformin: 0.07149 ±0.0036 versus 0.04301 ±0.0032 or 0.04295±0.0115 gram, P