Browsing by Author "Kao, Chinghai"

Now showing 1 - 10 of 11
  • Thumbnail Image
    Item
    1021. VP22 Mediates Tumor Vasculature Specific Targeting
    (Elsevier, 2004-05-01) Raikwar, Sudhanshu P.; Gardner, Thomas A.; Kao, Chinghai; Urology, School of Medicine
  • Thumbnail Image
    Item
    Adenoviral Vectors Expressing Human Endostatin–Angiostatin and Soluble Tie2: Enhanced Suppression of Tumor Growth and Antiangiogenic Effects in a Prostate Tumor Model
    (Elsevier, 2005-12-01) Raikwar, Sudhanshu P.; Temm, Constance J.; Raikwar, Nandita S.; Kao, Chinghai; Molitoris, Bruce A.; Gardner, Thomas A.; Urology, School of Medicine
    Angiogenesis is essential for prostate cancer development and metastasis. Antiangiogenic therapy targeting tumor neovasculature, therefore, represents a promising approach for prostate cancer treatment. We hypothesized that adenoviral-mediated delivery of a combination of antiangiogenic factors might have an enhanced antitumor response. We developed the adenoviral vectors Ad-hEndo-angio, expressing a unique, chimeric human endostatin–angiostatin fusion protein, and Ad-sTie2, expressing a soluble form of endothelium-specific receptor tyrosine kinase Tie2. Matrigel angiogenesis assays using Ad-hEndo-angio revealed significant inhibition of tubular network formation and endothelial sprouting compared to Ad-sTie2. In vivo studies in a bilateral PC-3 tumor xenograft model following either intratumoral or systemic administration of Ad-hEndo-angio led to enhanced tumor growth suppression compared to Ad-sTie2. A novel finding is that an intratumoral, combination therapy employing one-half the dose of Ad-hEndo-angio as well as Ad-sTie2 led to a complete regression of the injected, as well as the contralateral uninjected, tumor and prolonged the tumor-free survival in 80% of the animals. In addition, a novel, real-time, intravital imaging modality was used to monitor antiangiogenic responses following adenoviral-mediated gene transfer. These results suggest that a combinatorial antiangiogenic gene therapy approach involving Ad-hEndo-angio and Ad-sTie2 could become a novel form of treatment for localized human prostate cancer.
  • Thumbnail Image
    Item
    ANTI-TUMOR AND RADIO-SENSITIZING PROPERTIES OF AD-IU2, A PROSTATE-SPECIFIC REPLICATION-COMPETENT ADENOVIRUS ARMED WITH TRAIL
    (2009-03-18T18:58:00Z) Jimenez, Juan Antonio; Gardner, Thomas A.; Kao, Chinghai; Crabb, David W.; Harrington, Maureen A.; Roman, Ann
    In this thesis, I investigated the preclinical utility and antitumor efficacy of TRAIL delivered by Ad-IU2, a prostate-specific replication-competent adenovirus (PSRCA), against androgen-independent prostate cancer. Through transcriptional control of adenoviral early genes E1a, E1b and E4, as well as TRAIL by two bidirectional prostate-specific enhancing sequences (PSES), expression of TRAIL as well as adenoviral replication was limited to prostate-specific antigen and prostate-specific membrane antigen (PSA/PSMA)-expressing cells. Ad-IU2 replicated efficiently in and was restricted to PSA/PSMA-positive prostate cancer cells and induced 5-fold greater apoptosis in androgen-independent CWR22rv and C4-2 prostate cancer cells than the PSRCA control not expressing TRAIL. Ad-IU2 exhibited superior killing efficiency in PSA/PSMA-positive prostate cancer cells at doses 5 to 8-fold lower than that required by a non-TRAIL expressing PSRCA to produce a similar effect. This enhanced cytotoxic effect was not observed in non-prostatic cells, however. As an enhancement of its therapeutic efficacy, Ad-IU2 exerted a bystander effect through either direct cell-to-cell contact or soluble factors present in conditioned media from Ad-IU2-infected cells. In vivo, Ad-IU2, as compared to a control PSRCA, markedly suppressed the growth of subcutaneous CWR22rv xenografts at six weeks post-treatment (3.1 vs. 17.1-fold growth of tumor). The treatment of androgen-independent prostate cancer with Ad-IU2 prior to external beam radiation therapy (EBRT) significantly reduced clonogenic survival with dose reduction factors of 4.91 and 2.43 for CWR22rv and C4-2 cells, respectively. Radio-sensitization by Ad-IU2 was restricted to PSA/PSMA-positive cells. Combinatorial radio-gene therapy resulted in accumulation of cells in G1 phase and a perturbation of the radiation-induced G2 phase arrest. This multi-modal approach combining viral lysis, apoptosis-inducing gene therapy, and radiation therapy could have great impact in achieving complete local tumor control while reducing radiation dose and associated treatment morbidities. This would result in improvement of the clinical outcome of patients with high risk prostate cancer.
  • Thumbnail Image
    Item
    Docetaxel Increases Antitumor Efficacy of Oncolytic Prostate-Restricted Replicative Adenovirus by Enhancing Cell Killing and Virus Distribution
    (Wiley, 2010) Li, Xiong; Liu, Youhong; Tang, Yong; Roger, Phipps; Jeng, Meei-Huey; Kao, Chinghai; Urology, School of Medicine
    Background: We explored multiple molecular mechanisms of the combination of docetaxel and an oncolytic prostate-restricted replication competent adenovirus (Ad) (PRRA) in advanced prostate cancer (PCa) models. The combinational therapy has potential to overcome the therapeutic limitations of poor virus distribution inside solid tumors. Methods: We evaluated the effect of docetaxel on the antitumor efficacy and efficiency of virus transduction, transgene expression and virus distribution of PRRA in a prostate-specific antigen/prostate-specific membrane antigen-positive tumor xenograft model. We also evaluated the effect of docetaxel on apoptosis induction, cell killing and the efficiency of transgene expression and virus replication in vitro. Results: Tumor growth inhibition was significantly enhanced when docetaxel was administrated before intratumor injection of PRRA. In vivo dual-photon microscopy and ex vivo fluorescence microscopy and immunohistochemistry showed that docetaxel increased transgene expression and expanded virus distribution. The combination of docetaxel and PRRA also increased cell apoptosis. In vitro, docetaxel significantly increased cell killing in PRRA-treated PCa cells. Docetaxel significantly increased Ad-mediated trangene expression independent of Ad binding receptors and replication capability. Docetaxel increased the activity of cytomegalovirus (CMV) promoter but not of a chimeric prostate-specific enhancer, resulting in higher transgene expression. The enhanced CMV promoter activity resulted from activation of p38 mitogen-activated protein kinase (MAPK) because inhibition of p38 MAPK blocked the docetaxel-induced increase in CMV promoter activity. Conclusions: Combining docetaxel with an oncolytic PRRA improved therapeutic potential by expanding virus distribution and enhancing cell apoptosis and killing. These studies suggested a novel mechanism for enhancing the effect of therapeutic genes delivered by a PRRA.
  • Thumbnail Image
    Item
    Lovastatin enhances adenovirus-mediated TRAIL induced apoptosis by depleting cholesterol of lipid rafts and affecting CAR and death receptor expression of prostate cancer cells
    (Impact Journals, LLC, 2015-02-20) Liu, Youhong; Chen, Lin; Gong, Zhicheng; Shen, Liangfang; Kao, Chinghai; Hock, Janet M.; Sun, Lunquan; Li, Xiong; Department of Urology, IU school of Medicine
    Oncolytic adenovirus and apoptosis inducer TRAIL are promising cancer therapies. Their antitumor efficacy, when used as single agents, is limited. Oncolytic adenoviruses have low infection activity, and cancer cells develop resistance to TRAIL-induced apoptosis. Here, we explored combining prostate-restricted replication competent adenovirus-mediated TRAIL (PRRA-TRAIL) with lovastatin, a commonly used cholesterol-lowering drug, as a potential therapy for advanced prostate cancer (PCa). Lovastatin significantly enhanced the efficacy of PRRA-TRAIL by promoting the in vivo tumor suppression, and the in vitro cell killing and apoptosis induction, via integration of multiple molecular mechanisms. Lovastatin enhanced PRRA replication and virus-delivered transgene expression by increasing the expression levels of CAR and integrins, which are critical for adenovirus 5 binding and internalization. Lovastatin enhanced TRAIL-induced apoptosis by increasing death receptor DR4 expression. These multiple effects of lovastatin on CAR, integrins and DR4 expression were closely associated with cholesterol-depletion in lipid rafts. These studies, for the first time, show correlations between cholesterol/lipid rafts, oncolytic adenovirus infection efficiency and the antitumor efficacy of TRAIL at the cellular level. This work enhances our understanding of the molecular mechanisms that support use of lovastatin, in combination with PRRA-TRAIL, as a candidate strategy to treat human refractory prostate cancer in the future.
  • Thumbnail Image
    Item
    Novel Prostate-Specific Promoter Derived from PSA and PSMA Enhancers
    (Elsevier, 2002-09) Lee, Sang-Jin; Kim, Hong-Sup; Yu, Rong; Lee, KangRyul; Gardner, Thomas A.; Jung, Chaeyong; Jeng, Meei-Huey; Yeung, Fan; Cheng, Liang; Kao, Chinghai; Pathology and Laboratory Medicine, School of Medicine
    The expression of prostate-specific membrane antigen (PSMA) and prostate-specific antigen (PSA), two well characterized marker proteins, remains highly active in the hormone refractory stage of prostate cancer. In this study, an artificial chimeric enhancer (PSES) composed of two modified regulatory elements controlling the expression of PSA and PSMA genes was tested for its promoter activity and tissue specificity using the reporter system. As a result, this novel PSES promoter remained silent in PSA- and PSMA-negative prostate and non-prostate cancer cell lines, but mediated high levels of luciferase in PSA- and PSMA-expressing prostate cancer cell lines in the presence and absence of androgen. To determine whether PSES could be used for in vivo gene therapy of prostate cancer, a recombinant adenovirus, Ad-PSES-luc, was constructed. Luciferase activity in prostate cancer cell lines mediated by Ad-PSES-luc was 400- to 1000-fold higher than in several other non-prostate cell lines, suggesting the high tissue-specificity of the PSES promoter in an adenoviral vector. Finally, recombinant virus Ad-PSES-luc was injected into mice to evaluate the tissue-discriminatory promoter activity in an experimental animal. Unlike Ad-CMV-luc, the luciferase activity from systemic injection of Ad-PSES-luc was fairly low in all major organs. However, when injected into prostate, Ad-PSES-luc drove high luciferase activity almost exclusively in prostate and not in other tissues. Our results demonstrated the potential use of PSES for the treatment of androgen-independent prostate cancer patients.
  • Thumbnail Image
    Item
    The Role of Interleukin-12 on Modulating Myeloid-Derived Suppressor Cells
    (2011-03-10) Steding, Catherine E.; Kao, Chinghai; Gardner, Thomas A.; Brutkiewicz, Randy R.; Smith, Martin L.; Herbert, Brittney-Shea
    More than 200,000 American women are diagnosed with breast cancer each year. Although therapies effective in treating metastatic breast cancer currently exist, each year approximately 40,000 women die from this disease. Current evidence indicates that anti-cancer immune responses can be induced by vaccination in situ to the growth of metastasis and protect patients from the tumor recurrence. However, induction of anticancer immune responses may be limited in their efficacy due to immune suppression mechanisms induced by the developing cancer. Myeloid-derived suppressor cells are one population of immune regulators comprised of immature cells of myeloid origin with important roles in blocking immune activation and promoting tumor progression. Elimination or maturation of these cells has been found to promote enhanced anti-tumor effects and improve overall survival. This thesis identifies a new role for interleukin-12 as a modulator of myeloid-derived suppressor cell activity. Interleukin-12 was found to promote up-regulation of cell maturation markers on the surface of myeloid-derived suppressor cells with an accompanying decrease in factors responsible for conferring suppressive activity such as nitric oxide synthase 2 and arginase I. The alterations in myeloid-derived suppressor cells were observed following both in vitro and in vivo treatment with interleukin-12. Further analysis of the anti-tumor efficacy of interleukin-12 revealed that at least part of its suppression of tumor growth can be linked to reductions in myeloid-derived suppressor cell populations in the tumor microenvironment and an influx of active CD8+ T cells into the tumor microenvironment. The findings outlined in this thesis show that interleukin-12 alters the suppressive function of myeloid-derived suppressor cells leading to significant immune infiltration and activation resulting in increased overall survival and a reduction in metastasis.
  • Thumbnail Image
    Item
    Synergy between Angiostatin-Endostatin and Tie-2: A Novel Anti-Angiogenic Gene Therapy for Prostate Cancer
    (Elsevier, 2004-05-01) Raikwa, Sudhanshu P.; Kao, Chinghai; Gardner, Thomas A.; Urology, School of Medicine
  • Thumbnail Image
    Item
    Targeting Prostate Cancer with Conditionally Replicative Adenovirus Using PSMA Enhancer
    (ScienceDirect, 2004-12-01) Lee, Sang-Jin; Zhang, Yanping; Lee, Sang Don; Jung, Chaeyong; Li, Xiong; Kim, Hong-Sup; Bae, Kyung-Hee; Jeng, Meei-Huey; Kao, Chinghai; Gardner, Thomas; Urology, School of Medicine
    Prostate cancer is the second most commonly diagnosed cancer in men and accounts for significant mortality and morbidity in the United States. Initially androgen-dependent, prostate cancer ultimately becomes androgen-independent, which makes the disease extremely difficult to cure. In this study, we examined the use of conditionally replication-competent adenovirus for the treatment of hormone-independent prostate cancer. We utilized PSME, an enhancer element for prostate-specific PSMA expression, to control viral E1A protein expression and achieve exclusive virus replication in prostate. Western blotting confirmed that PSME mediated high E1A protein expression in PSMA-positive, androgen-independent prostate cancer cells (C4-2 and CWR22rv), but was much less active in PSMA-negative cancer cells (PC-3 and A549). Consistent with E1A protein expression, the recombinant adenovirus Ad5-PSME-E1a replicated in C4-2 and CWR22rv almost as efficiently as wild type with low levels of androgen, but its replication was significantly attenuated in PSMA-negative cells. In the in vitro killing assay, Ad5-PSME-E1a lysed all C4-2 and CWR22rv cells 5 days after infection, with minimal effect on PSMA-negative cells. In addition, injections of 1.7 × 108 plaque-forming units in a CWR22rv xenograft model in nude mice induced significant tumor growth delay, with a substantial necrotic area. These studies suggest that PSME-driven replication-competent adenovirus may be a new therapeutic modality for prostate cancer patients after hormone ablation therapy.
  • Thumbnail Image
    Item
    Therapeutic Targeting of Sunitinib-Induced AR Phosphorylation in Renal Cell Carcinoma
    (AACR, 2018-06) Adelaiye-Ogala, Remi; Damayanti, Nur D.; Orillion, Ashley R.; Arisa, Sreevani; Chintala, Sreenivasulu; Titus, Mark A.; Kao, Chinghai; Pili, Roberto; Medicine, School of Medicine
    Androgen receptor (AR) plays a crucial role in the development and progression of prostate cancer. AR expression has also been reported in other solid tumors, including renal cell carcinoma (RCC), but its biological role here remains unclear. Through integrative analysis of a reverse phase protein array, we discovered increased expression of AR in an RCC patient–derived xenograft model of acquired resistance to the receptor tyrosine kinase inhibitor (RTKi) sunitinib. AR expression was increased in RCC cell lines with either acquired or intrinsic sunitinib resistance in vitro. An AR signaling gene array profiler indicated elevated levels of AR target genes in sunitinib-resistant cells. Sunitinib-induced AR transcriptional activity was associated with increased phosphorylation of serine 81 (pS81) on AR. Additionally, AR overexpression resulted in acquired sunitinib resistance and the AR antagonist enzalutamide-induced AR degradation and attenuated AR downstream activity in sunitinib-resistant cells, also indicated by decreased secretion of human kallikrein 2. Enzalutamide-induced AR degradation was rescued by either proteasome inhibition or by knockdown of the AR ubiquitin ligase speckle-type POZ protein (SPOP). In vivo treatment with enzalutamide and sunitinib demonstrated that this combination efficiently induced tumor regression in a RCC model following acquired sunitinib resistance. Overall, our results suggest the potential role of AR as a target for therapeutic interventions, in combination with RTKi, to overcome drug resistance in RCC.