Intratumoral Therapy Research Articles

Intratumoural interleukin 12 gene therapy stimulates the immune system and decreases angiogenesis in dogs with spontaneous cancer.

Interleukin 12 (IL-12) is a powerful immunostimulatory cytokine with a strong antitumoural activity. In this work, the immunological, anti-angiogenic and clinical effects of three consecutive intratumoural IL-12 electrogene therapy (EGT) treatments were evaluated in nine dogs with spontaneous cancer. In all the dogs, tumour biopsies and blood samples were taken prior, during and after the intratumoural IL-12 EGT (on days 1, 8, 35 and 1, 3, 8, 15, 35, respectively). An initial decrease in immune cells was followed by an increase above baseline 1-3 weeks after treatment initiation. Interestingly, the decrease in peripheral leukocytes 2 days after the first intratumoural IL-12 EGT coincided with erythema and tumour swelling. Transient increases of IL-12 and interferon γ were measured in the serum and the tumour tissue, whereas IL-10 transiently increased only in the serum. The effect of intratumoural IL-12 EGT on the levels of IL-24 and vascular endothelial growth factor in the sera and tumour biopsies differed per dog. Via contrast-enhanced ultrasound (US) (on days 1, 8 and 35), we demonstrated that intratumoural IL-12 EGT resulted in a significant decrease of the relative blood volume and blood flow speed in the tumour compared with baseline. Metastases were present in two dogs. In one of these dogs, IL-12 EGT of the primary tumour caused a transient partial regression of the metastases, but not of the primary tumour. The second dog with metastases did not survive long enough to complete the entire treatment cycle. Despite encouraging immunostimulatory and anti-angiogenic effects after intratumoural IL-12 EGT, no clinically relevant outcomes were observed in this study, as persistent tumour regression could not be obtained. On the other hand, the laboratory and US results hold great promise for combinatorial strategies of intratumoural IL-12 EGT with conventional antitumour (immuno)therapies.

Injectable polypeptide micelles that form radiation crosslinked hydrogels in situ for intratumoral radiotherapy

Intratumoral radiation therapy – ‘brachytherapy’ – is a highly effective treatment for solid tumors, particularly prostate cancer. Current titanium seed implants, however, are permanent and are limited in clinical application to indolent malignancies of low- to intermediate-risk. Attempts to develop polymeric alternatives, however, have been plagued by poor retention and off-target toxicity due to degradation. Herein, we report on a new approach whereby thermally sensitive micelles composed of an elastin-like polypeptide (ELP) are labeled with the radionuclide 131I to form an in situ hydrogel that is stabilized by two independent mechanisms: first, body heat triggers the radioactive ELP micelles to rapidly phase transition into an insoluble, viscous coacervate in under 2min; second, the high energy β-emissions of 131I further stabilize the depot by introducing crosslinks within the ELP depot over 24h. These injectable brachytherapy hydrogels were used to treat two aggressive orthotopic tumor models in athymic nude mice: a human PC-3 M-luc-C6 prostate tumor and a human BxPc3-luc2 pancreatic tumor model. The ELP depots retained greater than 52% and 70% of their radioactivity through 60days in the prostate and pancreatic tumors with no appreciable radioactive accumulation (≤0.1% ID) in off-target tissues after 72h. The 131I-ELP depots achieved >95% tumor regression in the prostate tumors (n=8); with a median survival of more than 60days compared to 12days for control mice. For the pancreatic tumors, ELP brachytherapy (n=6) induced significant growth inhibition (p=0.001, ANOVA) and enhanced median survival to 27days over controls.

Sox2 cooperates with Lkb1 loss to promote squamous cell lung cancer

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Abstract B185: Induction of specific immunity to MUC1 antigen by tumor irradiation and cancer vaccines in murine tumor models

Abstract We have previously demonstrated that tumor irradiation potentiates cancer vaccines using genetic modification of tumor cells in murine tumor models. We showed that prior tumor irradiation enhanced the response of mice to intratumoral gene therapy with an IL-2 adenovector for non-immunogenic tumors. To investigate whether tumor irradiation augments the immune response to a specific tumor antigen, we have now tested the efficacy of tumor irradiation to enhance the therapeutic effect of MVA-MUC1-IL2 cancer vaccine (Transgene TG4010) for the treatment of murine renal adenocarcinoma Renca cells transfected with MUC1. Established subcutaneous (s.c.) Renca-MUC1 tumors (18mm3) were irradiated with 8 Gy on day 11 and peritumoral s.c. injections of MVA-MUC1-IL2 vector were administered at 106- 107 PFU on day 12 and 20. Tumor growth delays were monitored by tumor measurements and histological responses were evaluated following treatment with radiation alone, vector alone, radiation + MVA-MUC1-IL2 vector or radiation + MVA empty vector. Histological evaluation of tumors at an early time point, by 2-3 weeks after radiation and cancer vaccine, revealed that tumors treated with radiation and vaccine showed extensive areas of necrosis due to complete tumor destruction. Intense hemorrhages were observed due to disruption of tumor vasculature. Small areas of remaining tumor showed apoptotic tumor cells and degenerating giant tumor cells typical of radiation-induced changes. At the periphery of the tumor and infiltrating the tumor, we observed large bands of inflammatory cells including lymphocytes and macrophages as well as fibroblasts spindled shaped cells. Immuno-histochemical staining with CD45 leukocyte marker and F4/80 macrophage marker confirmed extensive infiltration of leukocytes and macrophages at the periphery and inside of areas of tumor destruction. These alterations were not as pronounced with radiation alone suggesting a drastic effect of the combined radiation + vaccine therapy on the tumor microenvironment. Radiation induced tumor growth delays for about 15 days but longer tumor growth delays of 30-35 days were observed with radiation + MVA-MUC1-IL2. By day 55, over 30% of the mice treated with radiation + MVA-MUC1-IL2 had a complete response with no sign of tumor whereas no responders were observed with either radiation alone or cancer vaccine alone. Complete responders were immune to rechallenge with Renca-MUC1 cells. These findings suggest that tumor irradiation given prior to cancer vaccine augments a specific immune response targeted at a specific tumor antigen that results in specific tumor immunity. The mechanisms of interaction between tumor irradiation and gene-mediated immunotherapy could include radiation-induced alterations in the tumor microenvironment, as those observed histologically in our studies, which could facilitate a more effective anti-tumor immune response. These include radiation-induced apoptosis and necrosis of tumor cells causing tumor-debulking and release of tumor antigens for APC presentation. Inflammatory cells mobilized in the tumor by radiation-induced tissue damage could subsequently be activated by the immune response triggered by the cancer vaccine. These studies support investing further pre-clinical and clinical efforts to combine radiotherapy with cancer vaccines for the treatment of cancer. Citation Format: Gilda Gali Hillman, Matthew D. Fountain, Shoshana E. Rothstein, Lyndsey Reich, Lisa Abernathy, Christopher K. Yunker, Fulvio Lonardo, Philippe Slos. Induction of specific immunity to MUC1 antigen by tumor irradiation and cancer vaccines in murine tumor models. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr B185.

Enhancing the Anti-Tumor Effects of Cancer Peptide Vaccine Therapy

The clinical efficacy of cancer peptide vaccines has been considered inadequate. To enhance the anti-tumor effects of peptide vaccines, we have studied effective enhancement methods for peptide vaccine therapies such as intratumoral peptide injection and combination therapies with anti-PD-1 blocking antibody or anti-CD4 depletion antibody. We aim to present effective clinical applications of peptide vaccines.

Spatiotemporally photoradiation-controlled intratumoral depot for combination of brachytherapy and photodynamic therapy for solid tumor

In an attempt to spatiotemporally control both tumor retention and the coverage of anticancer agents, we developed a photoradiation-controlled intratumoral depot (PRCITD) driven by convection enhanced delivery (CED). This intratumoral depot consists of recombinant elastin-like polypeptide (ELP) containing periodic cysteine residues and is conjugated with a photosensitizer, chlorin-e6 (Ce6) at the N-terminus of the ELP. We hypothesized that this cysteine-containing ELP (cELP) can be readily crosslinked through disulfide bonds upon exposure to oxidative agents, specifically the singlet oxygen produced during photodynamic stimulation. Upon intratumoral injection, CED drives the distribution of the soluble polypeptide freely throughout the tumor interstitium. Formation and retention of the depot was monitored using fluorescence molecular tomography imaging. When imaging shows that the polypeptide has distributed throughout the entire tumor, 660-nm light is applied externally at the tumor site. This photo-radiation wavelength excites Ce6 and generates reactive oxygen species (ROS) in the presence of oxygen. The ROS induce in situ disulfide crosslinking of the cysteine thiols, stabilizing the ELP biopolymer into a stable therapeutic depot. Our results demonstrate that this ELP design effectively forms a hydrogel both in vitro and in vivo. These depots exhibit high stability in subcutaneous tumor xenografts in nude mice and significantly improved intratumoral retention compared to controls without crosslinking, as seen by fluorescent imaging and iodine-125 radiotracer studies. The photodynamic therapy provided by the PRCITD was found to cause significant tumor inhibition in a Ce6 dose dependent manner. Additionally, the combination of PDT and intratumoral radionuclide therapy co-delivered by PRCITD provided a greater antitumor effect than either monotherapy alone. These results suggest that the PRCITD could provide a stable platform for delivering synergistic, anti-cancer drug depots.

ATPS-30INTRATUMORAL MODULATION THERAPY FOR GLIOBLASTOMA

BACKGROUND: There is a critical need for innovative and effective treatment strategies for glioblastoma (GBM). The clinical indications for neuromodulation therapy in the brain are rapidly expanding and this technique is now the standard of surgical care for select neurological diseases (e.g., Parkinson's Disease). It is well known that glial tumors are vulnerable to perturbations of the electrochemical environment; however, direct neuromodulation techniques have not been exploited for glioma management. METHODS: Our group has developed an in vitro model to deliver continuous alternating or pulsed, low voltage electric current directly into GBM cultures, a technique we call intratumoral modulation therapy (IMT). GBM cell lines and primary GBM cells derived from operative specimens were studied for vulnerability to IMT without and with temozolomide (TMZ) or oncogene-targeting strategies. An F98 rat GBM model has also been established to evaluate the benefits of IMT in vivo. RESULTS: We report a marked vulnerability of patient GBM cells, but not primary neurons, to a spectrum of IMT parameters. GBM cells treated with IMT undergo enhanced caspase 3-activation and apoptosis, and develop heightened sensitivity to TMZ. Uptake and biodistribution of siRNA was enhanced in primary GBM cells, along with target gene knockdown and functional effect, in the presence of IMT. Preliminary in vivo studies indicate that IMT markedly attenuates GBM growth without significant treatment-related morbidity. CONCLUSIONS: The proposed use of minimally invasive implantable stimulation devices offers distinct advantages over existing electrotherapies, including direct lesion targeting for delivery of continuous IMT, titratible stimulation settings to maximize benefit and lessen off-target effects and low maintenance, concealed hardware for improved self-perception and quality of life. Results from these investigations provide proof of principle evidence that supports further evaluation of IMT for the treatment of GBM.

Current status of intratumoral therapy for glioblastoma.

With emerging drug delivery technologies becoming accessible, more options are expected to become available to patients with glioblastoma (GBM) in the near future. It is important for clinicians to be familiar with the underlying mechanisms and limitations of intratumoral drug delivery, and direction of recent research efforts. Tumor-adjacent brain is an extremely complex living matrix that creates challenges with normal tissue intertwining with tumor cells. For convection-enhanced delivery (CED), the role of tissue anisotropy for better predicting the biodistribution of the infusate has recently been studied. Computational predictive methods are now available to better plan CED therapy. Catheter design and placement—in addition to the agent being used—are critical components of any protocol. This paper overviews intratumoral therapies for GBM, highlighting key anatomic and physiologic perspectives, selected agents (especially immunotoxins), and some new developments such as the description of the glymphatic system.

Abstract 1809: Next-generation brachytherapy: a preclinical study of a thermally stabilized biopolymer gel for delivering intratumoral radionuclide therapy in a pancreatic tumor mouse model

Abstract The intratumoral delivery of radioactive therapeutics, a clinical technique known as brachytherapy, has proven very successful in treating solid cancers and become a prevalent option for treating prostate, breast, and melanoma tumors. The method typically involves the permanent implantation of 80-120 titanium ‘seeds’ encapsulating radioactive isotopes and requires expert spatial placement to ensure full dose coverage. The disadvantages of the seeds include a complicated implantation process, the permanence of the implants, migration of seeds to off-target sites, and that the titanium shielding limits the application of radionuclides which could treat more aggressive forms of cancer. As such, we have developed a next-generation brachytherapy alternative to solid seeds using an injectable, biodegradable, biocompatible and thermosensitive elastin-like polypeptide (ELP). Through recombinant design and synthesis, ELP exhibits a thermal phase transition (soluble-to-insoluble) when heated above 21°C. This allows radionuclide-bearing ELP to be easily handled as a fluid at room temperature, but enables spontaneous self-assembly into a stable brachytherapy gel upon intratumoral injection at body temperature. Previously, we demonstrated the efficacy of ELP brachytherapy in treating both s.c. human hypopharyngeal tumors and orthotopic human prostate tumors xenografted in mice models. Treatment options for pancreatic cancer remain limited due to a large proportion of patients presenting with advanced disease at the time of diagnosis. Trials investigating the use of brachytherapy as a neo-adjuvant for shrinking pancreatic tumors prior to surgery or as an adjuvant to inhibit recurrence have provided encouragement. By conjugating the more potent radionuclide 131-Iodine to ELP, we investigated the ability of ELP brachytherapy to treat more clinically aggressive pancreatic tumors. Utilizing a human CRL-1687 cell line transfected to express luciferase (BxPc3-luc2), human pancreatic tumors were xenografted into an orthotopic, athymic nu/nu mouse model. Upon reaching 150 mm^3 in size, mice were treated either with [131I]-ELP brachytherapy (n = 6), at a dose of 5.83 μCi/mm^3, or with an ELP-only control injection (n = 6). Tumor response was tracked non-invasively using luminescent imaging for 60 days. The ELP brachytherapy demonstrated significant tumor inhibition (p < 0.05, one-way ANOVA) and no appreciable side effects as determined by weight loss. The therapy group experienced a significant survival benefit, with a median duration of 27 days (p < 0.005, log-rank test), when compared to control mice. These results, while promising as a proof of concept, demonstrate that further development is required to determine the both the appropriate radiation dose and to intratumoral coverage for translational application. Citation Format: Jeffrey Laurence Schaal, Wenge Liu, Ashutosh Chilkoti, Xinghai Li, Eric Mastria, Michael R. Zalutsky. Next-generation brachytherapy: a preclinical study of a thermally stabilized biopolymer gel for delivering intratumoral radionuclide therapy in a pancreatic tumor mouse model. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1809. doi:10.1158/1538-7445.AM2015-1809

Mo1496 Endoscopic Ultrasound Guided (EUS) Fiducial Marker Placement Without Fluoroscopy - Safety and Technical Feasibility

Mo1496 Endoscopic Ultrasound Guided (EUS) Fiducial Marker Placement Without Fluoroscopy - Safety and Technical Feasibility

Adjuvant TNF-α therapy to electrochemotherapy with intravenous cisplatin in murine sarcoma exerts synergistic antitumor effectiveness.

BackgroundElectrochemotherapy is a tumour ablation modality, based on electroporation of the cell membrane, allowing non-permeant anticancer drugs to enter the cell, thus augmenting their cytotoxicity by orders of magnitude. In preclinical studies, bleomycin and cisplatin proved to be the most suitable for clinical use. Intravenous administration of cisplatin for electrochemotherapy is still not widely accepted in the clinics, presumably due to its lower antitumor effectiveness, but adjuvant therapy by immunomodulatory or vascular-targeting agents could provide a way for its potentiation. Hence, the aim of the present study was to explore the possibility of adjuvant tumour necrosis factor α (TNF-α) therapy to potentiate antitumor effectiveness of electrochemotherapy with intravenous cisplatin administration in murine sarcoma.Materials and methodsIn vivo study was designed to evaluate the effect of TNF-α applied before or after the electrochemotherapy and to evaluate the effect of adjuvant TNF-α on electrochemotherapy with different cisplatin doses.ResultsA synergistic interaction between TNF-α and electrochemotherapy was observed. Administration of TNF-α before the electrochemotherapy resulted in longer tumour growth delay and increased tumour curability, and was significantly more effective than TNF-α administration after the electrochemotherapy. Tumour analysis revealed increased platinum content in tumours, TNF-α induced blood vessel damage and increased tumour necrosis after combination of TNF-α and electrochemotherapy, indicating an anti-vascular action of TNF-α. In addition, immunomodulatory effect might have contributed to curability rate of the tumours.ConclusionAdjuvant intratumoural TNF-α therapy synergistically contributes to electrochemotherapy with intravenous cisplatin administration. Due to its potentiation at all doses of cisplatin, the combined treatment is predicted to be effective also in tumours, where the drug concentration is suboptimal or in bigger tumours, where electrochemotherapy with intravenous cisplatin is not expected to be sufficiently effective.

Endoscopic ultrasound.guided fine-needle tissue acquisition – A review and update of literature

AbstractEver since the first endoscopic ultrasound-guided fine needle aspiration (FNA) was done in 1992, the procedure has evolved to become an indispensable tool for tissue acquisition in patients with gastrointestinal tumors and periluminal lesions. With the growing evidence of neoadjuvant therapy and research into intratumoral therapy, the need to obtain tissue diagnosis for tumors is quite apparent. This review provides an overall perspective to the endosonographer on various issues that are a key for best practices in FNA, in addition to being an update for practicing experienced endosonographers.

Hapten-enhanced therapeutic effect in advanced stages of lung cancer by ultra-minimum incision personalized intratumoral chemoimmunotherapy therapy.

AimThe objective of the study reported here was to evaluate the therapeutic effects of hapten-enhanced chemoimmunotherapy in the treatment of advanced lung cancer by ultra-minimum incision personalized intratumoral chemoimmunotherapy (UMIPIC) and to analyze the effect of this immune booster.Materials and methodsA total of 97 patients with advanced lung cancer were treated with UMIPIC or intratumoral chemotherapy (ITCT). UMIPIC was delivered intratumorally in combination with a proprietary therapeutic regimen composed of three components – an oxidant, a cytotoxic drug, and hapten. ITCT applied using the same procedures and regimen, only without hapten. All data from the two groups were reviewed and analyzed. A total of 55 patients were treated with UMIPIC and 42 with ITCT. Patient responses were assessed with computed tomography scan 4–6 weeks after treatment, and all of the patients were followed until their deaths.ResultsMedian overall survival was 11.23 months in the UMIPIC (test) group and 5.62 months in the ITCT (control) group (P<0.01). The 6-month and 1-year survival rates of the UMIPIC and ITCT groups were 76.36% versus 45.23% (P<0.01) and 45.45% versus 23.81% (P<0.05), respectively. Two cycles of UMIPIC treatment (n=19) conferred a significant survival benefit compared with two cycles of ITCT (n=29); significant benefits in survival time were also found with UMIPIC (n=20) compared with ITCT (n=13) when both were utilized without adjuvant treatment.ConclusionThe hapten-enhanced clinical effect of UMIPIC conferred a superior survival time in patients with advanced lung cancer compared with ITCT. The addition of the hapten in UMIPIC demonstrates a significant advantage in terms of prolonged survival time.

A Role for Intralesional (Intratumoral) Therapy with Two Cytokines in the Management of Some High Risk Patients with Cutaneous Melanoma

A Role for Intralesional (Intratumoral) Therapy with Two Cytokines in the Management of Some High Risk Patients with Cutaneous Melanoma

Targeting the tumor microenvironment to enhance antitumor immune responses.

The identification of tumor-specific antigens and the immune responses directed against them has instigated the development of therapies to enhance antitumor immune responses. Most of these cancer immunotherapies are administered systemically rather than directly to tumors. Nonetheless, numerous studies have demonstrated that intratumoral therapy is an attractive approach, both for immunization and immunomodulation purposes. Injection, recruitment and/or activation of antigen-presenting cells in the tumor nest have been extensively studied as strategies to cross-prime immune responses. Moreover, delivery of stimulatory cytokines, blockade of inhibitory cytokines and immune checkpoint blockade have been explored to restore immunological fitness at the tumor site. These tumor-targeted therapies have the potential to induce systemic immunity without the toxicity that is often associated with systemic treatments. We review the most promising intratumoral immunotherapies, how these affect systemic antitumor immunity such that disseminated tumor cells are eliminated, and which approaches have been proven successful in animal models and patients.

Intratumoral Inhibition of C5a Using Anti-C5a Monoclonal Antibody Inhibits Lymphoma Progression

Background: The complement system can have both pro-inflammatory and immunosuppressive effects. Our preliminary studies demonstrated that C5a can limit antigen-specific responses, in part, by enhancing the induction of immunosuppressive T regulatory (Treg) cells by primary human antigen-presenting cells and malignant B cells. The current study explored the effect of intratumoral C5a on B lymphoma progression and intratumoral T cells using the A20 murine lymphoma mouse model.Methods:(A) Co-injection approach: Female Balb/C mice were subcutaneously injected with A20 B lymphoma cells mixed with either 20 μg of rat anti-mouse C5a neutralizing monoclonal antibody (mAb) or matching isotype control mAb. Tumor growth was followed and the phenotype of tumor-infiltrating lymphocytes analyzed by flow cytometry.(B) Therapeutic approach: Established subcutaneous A20 tumors (7-9 mm diameter) were treated intratumorally with 20 µg of anti-mouse C5a neutralizing mAb (considered as day 1). A second dose (20 µg) of mAb was given intratumorally on day 5. Control mice were treated similarly with matching isotype control mAb. Tumor growth was followed.Data was analyzed using standard t-test (for tumor growth and immune responses) and Log-rank (Mantel-Cox) test (for comparing survival).Results:(A) Co-injection approach: Co-injection of anti-C5a mAb at the time of tumor cell inoculation significantly delayed A20 tumor growth (Fig. 1; p<0.05) and led to prolonged survival of anti-C5a-treated tumor-bearing mice when compared to the control mice (p=0.001).Tumors from mice that were co-injected with anti-C5a mAb showed significantly higher infiltration of activated CD8+ T cells producing IFNg than the control mice (Fig. 2; p=0.034). Anti-C5a-treated mice also had a lower percentage of circulating Tregs (p=0.023) and splenic Tregs (p=0.0001) compared to control mice.(B) Therapeutic approach: Treatment of pre-established subcutaneous A20 tumors with anti-mouse C5a mAb slowed tumor growth significantly when compared to the control mice (Fig. 3; **p<0.01; *p<0.05). Tumor-bearing mice treated intratumorally with anti-C5a also showed significant improvement in the survival when compared to tumor-bearing mice treated with isotype control Ab (p=0.008).Conclusions:Intratumoral anti-C5a mAb therapy inhibits progression of B lymphoma and improves survival, likely by reducing immunosuppression. We are currently exploring the mechanisms behind C5a-promoted tumor immunosuppression. [Display omitted] [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Intratumoral anti-HuD immunotoxin therapy for small cell lung cancer and neuroblastoma.

BackgroundMost patients with small cell lung cancer (SCLC) or neuroblastoma (NB) already show clinically detectable metastases at diagnosis and have an extremely poor prognosis even when treated with combined modalities. The HuD-antigen is a neuronal RNA-binding protein that is expressed in 100% of SCLC tumor cells and over 50% of neuroblastoma cells. The correlation between high titers of circulating anti-HuD antibodies in patients and spontaneous tumor remission suggests that the HuD-antigen might be a potential molecular target for immunotherapy.MethodsWe have constructed a new antibody-toxin compound (called BW-2) by assembling a mouse anti-human-HuD monoclonal antibody onto streptavidin/saporin complexes.ResultsWe found that the immunotoxin BW-2 specifically killed HuD-positive human SCLC and NB cancer cells at very low concentrations in vitro. Moreover, intratumoral immunotoxin therapy in a nude mouse model of human SCLC (n = 6) significantly reduced local tumor progression without causing toxicity. When the same intratumoral immunotoxin protocol was applied to an immunocompetent A/J mouse model of NB, significant inhibition of local tumor growth was also observed. In neuroblastoma allografted A/J mice (n = 5) treated twice with intratumoral immunotoxin, significant tumor regression occurred in over 80% of the animals and their duration of tumor response was significantly prolonged.ConclusionsOur study suggests that anti-HuD based immunotoxin therapy may prove to be an effective alternative treatment for patients with SCLC and NB.

ET-27 * REPLICATION AND SPREAD OF ONCOLYTIC HERPES VIRUS IN GLIOMA STEM CELLS CAN BE ENHANCED BY SPECIFIC INHIBITION OF HISTONE DEACETYLASE 6

High-grade gliomas remain clinically challenging and under current therapies the prognosis is generally dismal. Intratumoral heterogeneity, therapy resistance, and tumor recurrence likely caused by glioma stem cells (GSCs) still represent major challenges, which need to be addresses by novel, multimodal therapies. We attempted to combine rQnestin34.5, an oncolytic herpes simplex virus expressing its ICP34.5 virulence gene under the glioma-specific nestin promoter, with specific inhibition of histone deacetylase 6 (HDAC6). We have previously reported that pan-HDAC inhibition using valproic acid enhances rQnestin34.5's antitumor activity and our data obtained in established glioma cell lines indicate that sole inhibition of HDAC6 can at least in part be accounted for this effect. We now analyzed the influence of the specific HDAC6 inhibitor Tubacin on rQnestin34.5 replication in GSC lines originating from proneural, classic, and mesenchymal glioma subtypes. Time-lapse microscopy revealed that plaque formation and spread were accelerated within the first 48 hours after infection when cells were pre-treated with Tubacin, translating into significantly increased cytotoxicity in the respective time frame. Viral DNA replication was enhanced after combination treatment as increased viral copy numbers per cell were detected by qPCR. Furthermore, HDAC6 inhibition increased mRNA expression levels of immediate early and late genes. Importantly, the positive effect of Tubacin on rQnestin34.5 replication and spread in GSCs was critically dependent on drug pre-treatment regimens and very low infectious titers. We also noted that the benefit of rQnestin34.5 oncolysis from HDAC6 inhibition varied quantitatively between GSCs. While responsiveness was not determined by glioma subtype or HDAC6 expression levels, we are currently investigating whether the choice of the exact viral entry mechanism can be used as a predictive marker. Future studies will also aim at establishing a therapeutic regimen demonstrating the potential benefit of HDAC6 inhibition in addition to herpes simplex oncolysis in a GSC-derived orthotopic glioma model.

Abstract LB-223: Intratumoral heterogeneity and precise personalized therapy revealed by one patient panel in hepatocellular carcinoma

Abstract Background: The diversity of cancer genome significantly influences drug response and impairs the discovery of biomarker for patient stratification. As important preclinical models, patient derived cell lines are widely used in drug discovery and biomarker screening, yet complicated by intratumoral heterogeneity. Methods: We created a One Patient Panel (OPP), that is, a set of cell lines (26 lines in this case) derived from tumor tissue from one hepatocellular carcinoma (HCC) patient, and systematically integrated the OPP by transcriptional profiling, chromosomal copy number variations (CNVs) and whole-exome sequencing. The pharmacological profiles of more than 70 targeted therapeutic agents were also examined in OPP. Results: CNVs data showed that 10 chromosomes contained no significant qualitative differences, while 13 chromosomes had obvious cytogenetical and cell-line specific alterations, among the 26 cell lines. Likewise, transcriptional profiling and drug response analysis indicated the presence of clinically relevant intratumoral heterogeneity in OPP. For examples, MEK pathway was highly active in 6 (23.1%) lines and completely inactive in 3 (11.5%) lines, mTOR pathway was active in about 50% of lines, and Sonic Hedgehog pathway was active in above 30% of lines. Yet, based on the drug screening data, 80% of drugs had similar response patterns among those lines in OPP, suggesting a close genetic background among them. Interestingly, FGFR and MEK inhibitors have dramatically distinct drug response patterns among those cell lines. In response to FGFR inhibitors, there were four sensitive lines with the IC50 lower than 250 nM and five resistant lines with IC50 higher than 5 μM. For MEK inhibitors, the IC50s of three sensitive lines were lower than 50 nM, while the resistant IC50s were higher than 1 μM. Thus, a maximum of 30-folds difference in sensitivity to targeted agents was observed among cell lines in OPP. Moreover, there were no overlaps between the two groups of sensitive lines to FGFR or MEK inhibitors. Despite response variations, different inhibitors against the same molecular target, such as BGJ398 (Novartis) and AZD4547 (Astrazeneca), both against FGFR, showed comparable sensitivity in the same cell lines, indicating those inhibitors might have same biomarker(s). Conclusions: Taken together, the OPP recapitulates the intratumoral genetic, molecular and pharmacological heterogeneity in HCC. Importantly ,the OPP provides a powerful platform for optimizing drug selection and biomarker discovery, which may speed up the emergence of precision therapeutic regimens. Citation Format: Qiang Gao, William Niu, Andrew Tse, Jeffrey Lin, Jian Zhou, Simon Shung, Jia Fan. Intratumoral heterogeneity and precise personalized therapy revealed by one patient panel in hepatocellular carcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr LB-223. doi:10.1158/1538-7445.AM2014-LB-223

Molecular imaging of targeted therapies with positron emission tomography: the visualization of personalized cancer care.

Molecular imaging has been defined as the visualization, characterization and measurement of biological processes at the molecular and cellular level in humans and other living systems. In oncology it enables to visualize (part of) the functional behaviour of tumour cells, in contrast to anatomical imaging that focuses on the size and location of malignant lesions. Available molecular imaging techniques include single photon emission computed tomography (SPECT), positron emission tomography (PET) and optical imaging. In PET, a radiotracer consisting of a positron emitting radionuclide attached to the biologically active molecule of interest is administrated to the patient. Several approaches have been undertaken to use PET for the improvement of personalized cancer care. For example, a variety of radiolabelled ligands have been investigated for intratumoural target identification and radiolabelled drugs have been developed for direct visualization of the biodistibution in vivo, including intratumoural therapy uptake. First indications of the clinical value of PET for target identification and response prediction in oncology have been reported. This new imaging approach is rapidly developing, but uniformity of scanning processes, standardized methods for outcome evaluation and implementation in daily clinical practice are still in progress. In this review we discuss the available literature on molecular imaging with PET for personalized targeted treatment strategies. Molecular imaging with radiolabelled targeted anticancer drugs has great potential for the improvement of personalized cancer care. The non-invasive quantification of drug accumulation in tumours and normal tissues provides understanding of the biodistribution in relation to therapeutic and toxic effects.