Fengzhi Li

Publications (39) View all

• Source

  Available from: Pasha Apontes

  Dataset: Molecular mechanism of upregulation of survivin transcription by the AT-rich DNA-binding ligand, Hoechst33342

  Jianguo Wu, Pasha Apontes, Lei Song, Ping Liang, Lily Yang, Fengzhi Li
• Article: An intravenous (i.v.) route-compatible formulation of FL118, a survivin, Mcl-1, XIAP, and cIAP2 selective inhibitor, improves FL118 antitumor efficacy and therapeutic index (TI).

  Xiang Ling, Fengzhi Li
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  ABSTRACT: We recently reported a novel anticancer small molecule, designated FL118, which was discovered via high throughput screening (HTS), and followed by hit-lead in vitro and in vivo analysis. FL118 selectively inhibits the expression of four major cancer survival-associated gene products (survivin, Mcl-1, XIAP, and cIAP2) and shows promising antitumor activity in animal models of human cancers when administered using a weekly x 4 schedule (Ling et al., PLOS ONE. 2012, 7: e45571). Here, we compared the antitumor efficacy and therapeutic index (TI) of FL118 in a newly developed Tween 80-free formulation that can be delivered intravenously (i.v.) and intraperitoneally (i.p.) against the previous Tween 80-containing formulation that can only be delivered via an i.p. route. We found that the maximum tolerated dose (MTD) for FL118 in the i.v. formulation increases 3-7 fold in comparison with the MTD of FL118 in the i.p. formulation. FL118 in the i.v. recipe was able to eliminate human tumor xenografts in all three major schedules tested (daily x 5, q2 x 5 and weekly x 5). In contrast, FL118 was able to eliminate human tumor xenografts in the i.p. formulation only with the weekly x 4 schedule previously reported. The TI of FL118 in the i.v. formulation reached 5-6 in the most effective schedule, while the TI of FL118 in the i.p. formulation was only 1.3 - 2. These findings overcome several clinical challenges including FL118 formulation to realize clinically compatible drug administration routes, and expanding effective treatment schedules. The striking improvement of the TI makes FL118 a much safer drug for further development toward clinical trials.
  American Journal of Translational Research 01/2013; 5(2):139-54.
• Article: Transcriptional inhibition of p21WAF1/CIP1 gene (CDKN1) expression by survivin is at least partially p53-dependent: evidence for survivin acting as a transcription factor or co-factor.

  Lei Tang, Xiang Ling, Wensheng Liu, Gokul M Das, Fengzhi Li
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  ABSTRACT: Growing evidence suggests a role for the antiapoptotic protein survivin in promotion of cancer cell G1/S transition and proliferation. However, the underlying mechanism is unclear. Further, although upregulation of p21(WAF1/CIP1) by p53 plays an important role in p53-mediated cell G1 arrests in response to various distresses, it is unknown whether survivin plays a role in the regulation of p21(WAF1/CIP1) expression. Here, we report that exogenous expression of survivin in p53-wild type MCF-7 breast cancer cells inhibits the expression of p21(WAF1/CIP1) protein, mRNA and promoter activity, while the survivin C84A mutant and antisense failed to do so. Cotransfection experiments in the p53 mutant H1650 lung cancer cell line showed that survivin neutralizes p53-induced p21(WAF1/CIP1) expression and promoter activity. Importantly, genetically silencing of endogenous survivin using lentiviral survivin shRNA also enhances endogenous p21 in p53 wild type cancer cells, suggesting the physiological relevance of the fining. We further demonstrated that both p53 and survivin interacts on the two p53-binding sites in the p21(WAF1/CIP1) promoter (-2313 to -2212; -1452 to -1310), and survivin physically interacts with p53 in cancer cells. Together, we propose that survivin may act as a transcription factor or cofactor to interact with p53 on the p21(WAF1/CIP1) promoter leading to the inhibition of p21(WAF1/CIP1) expression at least in part by neutralizing p53-mediated transcriptional activation of the p21 gene.
  Biochemical and Biophysical Research Communications 04/2012; 421(2):249-54. · 2.48 Impact Factor
• Article: Suppression of survivin promoter activity by YM155 involves disruption of Sp1-DNA interaction in the survivin core promoter.

  Qiuying Cheng, Xiang Ling, Andrew Haller, Takahito Nakahara, Kentaro Yamanaka, Aya Kita, Hiroshi Koutoku, Masahiro Takeuchi, Michael G Brattain, Fengzhi Li
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  ABSTRACT: YM155, a novel survivin suppressant, shows potent antitumor activity against various human cancers and is currently in phase II clinical trials. In this study, we investigated whether YM155 selectively inhibits survivin transcription. We hypothesize that inhibition of survivin transcription plays a role in YM155-mediated survivin inhibition. We found that YM155 inhibited survivin promoter activity, while it showed minimal inhibitory effect on four control gene promoters in transfection and luciferase activity assay experiments, indicating its selectivity. Transfection of various survivin promoter-luciferase constructs followed by luciferase assays revealed that the survivin core promoter (269 bp) plays a major role in YM155-mediated inhibitory effects. However, flow cytometry analysis indicated that inhibition of survivin promoter activity by YM155 is cell cycle-independent without G1 cell arrests. Electrophoretic mobility shift assays (EMSA) identified that YM155 abrogates nuclear proteins binding to the region of -149 to -71, in which Sp1 is a major candidate, and that YM155 treatment induces Sp1 re-subcellular localization without inhibiting its expression. Forced expression of Sp1 neutralized YM155-mediated downregulation of survivin promoter activity. Consistently, mutation of the identified Sp1 sites in the oligonucleotide probe diminished DNA-protein interactions in EMSA experiments, and mutation of the Sp1 sites in the survivin promoter-luciferase construct diminished survivin promoter activity. These findings indicate that YM155 inhibition of survivin expression is at least in part through its inhibition of survivin transcription by disruption of Sp1 interaction with the region of -149 to -71 in the survivin core promoter.
  International journal of biochemistry and molecular biology. 01/2012; 3(2):179-97.
• Article: A Novel Small Molecule FL118 That Selectively Inhibits Survivin, Mcl-1, XIAP and cIAP2 in a p53-Independent Manner, Shows Superior Antitumor Activity.

  Xiang Ling, Shousong Cao, Qiuying Cheng, James T Keefe, Youcef M Rustum, Fengzhi Li
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  ABSTRACT: Drug/radiation resistance to treatment and tumor relapse are major obstacles in identifying a cure for cancer. Development of novel agents that address these challenges would therefore be of the upmost importance in the fight against cancer. In this regard, studies show that the antiapoptotic protein survivin is a central molecule involved in both hurdles. Using cancer cell-based survivin-reporter systems (US 7,569,221 B2) via high throughput screening (HTS) of compound libraries, followed by in vitro and in vivo analyses of HTS-derived hit-lead compounds, we identified a novel anticancer compound (designated FL118). FL118 shows structural similarity to irinotecan. However, while the inhibition of DNA topoisomerase 1 activity by FL118 was no better than the active form of irinotecan, SN-38 at 1 µM, FL118 effectively inhibited cancer cell growth at less than nM levels in a p53 status-independent manner. Moreover, FL118 selectively inhibited survivin promoter activity and gene expression also in a p53 status-independent manner. Although the survivin promoter-reporter system was used for the identification of FL118, our studies revealed that FL118 not only inhibits survivin expression but also selectively and independently inhibits three additional cancer-associated survival genes (Mcl-1, XIAP and cIAP2) in a p53 status-independent manner, while showing no inhibitory effects on control genes. Genetic silencing or overexpression of FL118 targets demonstrated a role for these targets in FL118's effects. Follow-up in vivo studies revealed that FL118 exhibits superior antitumor efficacy in human tumor xenograft models in comparison with irinotecan, topotecan, doxorubicin, 5-FU, gemcitabine, docetaxel, oxaliplatin, cytoxan and cisplatin, and a majority of mice treated with FL118 showed tumor regression with a weekly × 4 schedule. FL118 induced favorable body-weight-loss profiles (temporary and reversible) and was able to eliminate large tumors. Together, the molecular targeting features of FL118 plus its superior antitumor activity warrant its further development toward clinical trials.
  PLoS ONE 01/2012; 7(9):e45571. · 4.09 Impact Factor