Significant Increase In Median Survival Research Articles

DIPG-12. ASSESSING THE EFFICACY OF BAY2402234 IN COMBINATION WITH ONC201 IN IMMUNE-COMPETENT MURINE MODELS OF DIFFUSE MIDLINE GLIOMA

Abstract BACKGROUND Radiation therapy remains the sole standard-of-care treatment for Diffuse Midline Glioma (DMG), an aggressive and lethal brain tumor. Despite numerous clinical trials, median overall survival has not improved. Therefore, precise preclinical modeling is essential to guide clinical trials toward positive patient outcomes. ONC201, a ClpP antagonist, has demonstrated efficacy in treating DMG (NCT05580562, NCT05476939). However, efficacy is short-term and acquired resistance necessitates combination therapies. Therefore, we assessed the efficacy of BAY2402234, a potent and selective Dihydroorotate Dehydrogenase (DHODH) inhibitor, in combination with ONC201 in a murine model of DMG. METHODS Forty 6-week-old C57/B6 mice underwent pontine orthotopic injection with isogenic DMG cells via stereotactic surgery. The cell line used, 24B-7, has a mutational profile (PDGFRA+p53+H3.3K27M) and growth morphology representative of pontine DMGs. In our previous work, untreated mice injected with these cells had a median survival of 58 days. Upon confirmation of tumor growth using IVIS, mice were assigned to treatment groups based on BLI signal, and treatment was initiated. When mice showed signs of tumor burden or >20% weight loss they were euthanized. At euthanasia, the brain was collected, sectioned sagittally, and divided between fixation and freezing. These samples will evaluate tumor growth, morphology, and characterization compared between treatment groups by both immunohistochemistry and western blot. RESULTS As expected, ONC201 treated mice demonstrated an increase in median survival compared to the untreated group. While well-tolerated, neither BAY2402234 nor the combination of BAY2402234 and ONC201 exhibited a statistically significant increase in median survival after statistical correction. (Vehicle: 55 days, ONC201: 62 days, p=0.0026; BAY2402234: 58.5 days, p=0.0403; Combination: 57 days, p=0.1491). Ongoing efforts include target validation and tumor analysis through western blot and immunohistochemistry. ONC201 treatment will be evaluated by investigating ATF4, DR5, and CHOP. BAY2402234 treatment will be evaluated by investigating phosphor-gH2AX and gH2AX. CONCLUSIONS Pending tumor analysis.

Evaluating CD133 as a Radiotheranostic Target in Small-Cell Lung Cancer.

Despite decades of work, small-cell lung cancer (SCLC) remains a frustratingly recalcitrant disease. Both diagnosis and treatment are challenges: low-dose computed tomography (the approved method used for lung cancer screening) is unable to reliably detect early SCLC, and the malignancy's 5 year survival rate stands at a paltry 7%. Clearly, the development of novel diagnostic and therapeutic tools for SCLC is an urgent, unmet need. CD133 is a transmembrane protein that is expressed at low levels in normal tissue but is overexpressed by a variety of tumors, including SCLC. We previously explored CD133 as a biomarker for a novel autoantibody-to-immunopositron emission tomography (PET) strategy for the diagnosis of SCLC, work that first suggested the promise of the antigen as a radiotheranostic target in the disease. Herein, we report the in vivo validation of a pair of CD133-targeted radioimmunoconjugates for the PET imaging and radioimmunotherapy of SCLC. To this end, [89Zr]Zr-DFO-αCD133 was first interrogated in a trio of advanced murine models of SCLC─i.e., orthotopic, metastatic, and patient-derived xenografts─with the PET probe consistently producing high activity concentrations (>%ID/g) in tumor lesions combined with low uptake in healthy tissues. Subsequently, a variant of αCD133 labeled with the β-emitting radiometal 177Lu─[177Lu]Lu-DTPA-A″-CHX-αCD133─was synthesized and evaluated in a longitudinal therapy study in a subcutaneous xenograft model of SCLC, ultimately revealing that treatment with a dose of 9.6 MBq of the radioimmunoconjugate produced a significant increase in median survival compared to a control cohort. Taken together, these data establish CD133 as a viable target for the nuclear imaging and radiopharmaceutical therapy of SCLC.

IMMU-23. FRUCTOSE METABOLISM IN MICROGLIA PROMOTES GLIOBLASTOMA GROWTH

Abstract Glioblastoma (GBM) is the most common brain malignancy in adults and has a dismal prognosis. Advances in standard-of-care treatments for GBM have not kept pace with those for other malignancies, in part due to the inefficacy of immunotherapies in treating GBM. The tumor microenvironment (TME) of GBM is heavily populated with pro-tumorigenic tumor-associated macrophages (TAMs) and lacks robust infiltration of T cells. Given that the number of TAMs in the TME correlates with poor prognosis, understanding the mechanisms by which they thrive is essential for discovering new therapies. Bulk RNASeq data from mouse tumors indicates that the fructose transporter, SLC2A5, is highly expressed on TAMs relative to peripheral myeloid cells. Furthermore, human glioblastoma single cell RNASeq (scRNASeq) data indicates that SLC2A5 is expressed specifically on microglia, the tissue resident macrophage of the brain. To assess the necessity of SLC2A5 in microglia, we orthotopically implanted CT2A or QPP4 glioblastoma cells into wild-type mice and mice lacking SLC2A5 (SLC2A5 KO mice). We observed a significant increase in median survival in SLC2A5 KO mice compared to wild-type mice. This indicates a necessity of fructose metabolism in microglia to promote tumorigenesis. Upon ex vivo analysis of the immune compartment of the TME, we observed that microglial cells from tumors in SLC2A5 KO mice have higher expression of MHC-II and PDL1 molecules on the cell surface compared to those from wild-type mice. Additionally, the CD4:CD8 T cell ratio in tumors from SLC2A5 KO mice was lower than that in tumors from wild-type mice. These data suggest that fructose metabolism in microglia facilitates an immunosuppressive phenotype that promotes GBM progression.

Blood-tumor barrier opening by MRI-guided transcranial focused ultrasound in a preclinical breast cancer brain metastasis model improves efficacy of combinatorial chemotherapy.

Patients with metastatic breast cancer have high and continually increasing rates of brain metastases. During the course of the disease, brain metastases can occur in up to 30% of these patients. In most cases, brain metastases are diagnosed after significant disease progression. The blood-tumor barrier increases the difficulty of treating brain metastasis by preventing accumulation of chemotherapy within metastases at therapeutically effective concentrations. Traditional therapies, such as surgical resection, radiotherapy, and chemotherapy, have poor efficacy, as reflected by a low median survival rate of 5-8% after post-diagnosis. Low-intensity focused ultrasound (LiFUS) is a new treatment for enhancing drug accumulation within the brain and brain malignancies. In this study, we elucidate the effect of clinical LiFUS combined with chemotherapy on tumor survival and progression in a preclinical model of triple-negative breast cancer metastasis to the brain. LiFUS significantly increased the tumor accumulation of 14C-AIB and Texas Red compared to controls (p< 0.01). LiFUS-mediated opening of the BTB is size-dependent, which is consistent with our previous studies. Mice receiving LiFUS with combinatorial Doxil and paclitaxel showed a significant increase in median survival (60 days) compared to other groups. LiFUS plus combinatorial chemotherapy of paclitaxel and Doxil also showed the slowest progression of tumor burden compared to chemotherapy alone or individual chemotherapy and LiFUS combinations. This study shows that combining LiFUS with timed combinatorial chemotherapeutic treatment is a potential strategy for improving drug delivery to brain metastases.

Cationic nanoparticles enhance T cell tumor infiltration and antitumor immune responses to a melanoma vaccine.

In clinical settings, cancer vaccines as monotherapies have displayed limited success compared to other cancer immunotherapeutic treatments. Nanoscale formulations have the ability to increase the efficacy of cancer vaccines by combatting the immunosuppressive nature of the tumor microenvironment. Here, we have synthesized a previously unexplored cationic polymeric nanoparticle formulation using polyamidoamine dendrimers and poly(d,l-lactic-co-glycolic acid) that demonstrate adjuvant properties in vivo. Tumor-challenged mice vaccinated with an adenovirus-based cancer vaccine [encoding tumor-associated antigen (TAA)] and subsequently treated with this nanoparticulate formulation showed significant increases in TAA-specific T cells in the peripheral blood, reduced tumor burden, protection against tumor rechallenge, and a significant increase in median survival. An investigation into cell-based pathways suggests that administration of the nanoformulation at the site of the developing tumor may have created an inflammatory environment that attracted activated TAA-specific CD8+ T cells to the vicinity of the tumor, thus enhancing the efficacy of the vaccine.

In vivo evaluation of oxidized multiwalled-carbon nanotubes-mediated hyperthermia treatment for breast cancer

Breast cancer is one of the most common types of cancer that contribute to high mortality worldwide. Hyperthermia (HT) was introduced as one of the alternative treatments to treat breast cancer but has major drawback of damaging normal adjacent cells. This study explores the integration effect of multiwalled‑carbon nanotubes (MWCNTs) in combination with hyperthermia treatment for breast cancer therapy regimes. In this study, acid-functionalized MWCNTs (ox-MWCNTs) were prepared by acid washing methods using H2SO4/HNO3 (98%/68%) with the ratio of 3:1 (ν/ν) and characterized by colloidal dispersibility test, FTIR, TGA, XRD, FESEM and EDX analysis. EMT6 tumor-bearing mice were treated with ox-MWCNTs in combination with local HT at 43 °C. The tumor progression was monitored and the influence of immune response was evaluated. Results from this study demonstrated that mice from ox-MWCNTs in combination with local HT treatment group experienced complete tumor eradication, accompanied by a significant increase in median survival of the mice. Histological and immunohistochemical analysis of tumor tissues revealed that tumor treated with combined treatment underwent cell necrosis and there was a significant reduction of proliferating cells when compared to the untreated tumor. This observation is also accompanied with an increase in Hsp70 expression in tumor treated with HT. Flow cytometry analysis of the draining lymph nodes showed an increase in dendritic cells infiltration and maturation in mice treated with combined treatment. In addition, a significant increase of tumor-infiltrated CD8+ and CD4+ T cells along with macrophages and natural killer cells was observed in tumor treated with combined treatment. Altogether, results presented in this study suggested the potential of ox-MWCNTs-mediated HT as an anticancer therapeutic agent, hence might be beneficial in the future of breast cancer treatment.

Combination of nanosomal form of doxorubicin, interferon alpha, and nitroglycerin in the threatment of 101.8 glioblastoma in Wistar rats

The search for effective approaches to the treatment of patients with glioblastoma is one of the difficult tasks of neurooncology; standard methods of therapy show limited results. Combined therapy, which includes different antitumor mechanisms, can increase its effectiveness. The combination of PLGA nanoform of doxorubicin (Dox-PLGA), antitumor cytokine — interferon alfa (IFN-α), and nitrogen oxide (NO) donor nitroglycerin (NG) was investigated in this work both in vitro (rat C6 glioma) and in vivo (rat 101.8 glioblastoma). MTT assay in the C6 cell line showed great cytotoxicity and antiproliferative effect of the combination of IFN-α with Dox-PLGA and NG. The lowest tumour cell survival was observed when using a high dose of IFN-α (10 ng/ml) in mono-mode. In the in vivo experiment, 32 female Wistar rats with 101.8 glioblastoma received therapy in the following modes: Dox-PLGA + NG; Dox-PLGA + IFN-α; Dox- PLGA + IFN-α + NG. There was a significant increase in median survival and life expectancy (ILE) in all groups receiving therapy compared to the group that did not undergo treatment. The longest median lifespan (27 days), survival up to 100 days (1 animal), ILE (131%) were observed in animals that received the combination Dox-PLGA + IFN-α+ NG, compared to the group without treatment, in which the median lifespan was 15 days. Thus, the therapy of experimental glioblastoma both in vivo and in vitro with the combination of Dox-PLGA + IFN-α + NG has the most pronounced therapeutic and antitumor effect, which must be taken into account when developing new more effective methods of treating human glioblastomas.

CD137 and PD-L1 targeting with immunovirotherapy induces a potent and durable antitumor immune response in glioblastoma models

BackgroundGlioblastoma (GBM) is a devastating primary brain tumor with a highly immunosuppressive tumor microenvironment, and treatment with oncolytic viruses (OVs) has emerged as a promising strategy for these tumors. Our...

The Effect of a Ketogenic Diet Concomitant With Chemotherapy in Pancreatic Ductal Adenocarcinoma Survival and Its Associated Cachexia

Abstract Objectives To evaluate the effect of a KD alone or in combination with the current chemotherapeutic drug gemcitabine (GEM) on morbidity and mortality in a clinically relevant genetically engineered LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx1-Cre (KPC) mouse model of PDA. Methods At three months old, KPC mice tumor size was measured by high-resolution ultrasound imaging of the pancreas. Male and female mice were allocated to either a control diet (CD; % kcal: 14% protein, 70% carb, 16% fat), a KD (%kcal: 14% protein, &amp;lt;1% carb, 85% fat), a CD + GEM, or a KD + GEM groups. GEM was administered at a dose of 100 mg/kg by i.p. injections 2x/wk for 7 times. Forelimb grip strength, body composition, and non-fasting glucose and ketone levels were evaluated at baseline, monthly and at time of sacrifice. Mice were euthanized upon reaching an endpoint criteria, which included ascites, weight loss &amp;gt; 20%, and/or extreme lethargy. Blood was drawn via cardiac puncture. Tissues were dissected and stored for further analysis. Results KPC mice fed a KD plus GEM exhibited a significant increase in median survival when compared to those fed CD alone. Only KPC mice fed a KD plus gemcitabine exhibited a significant increase in median survival compared to KPC mice fed a CD. KPC mice fed a CD, either alone or in combination with chemotherapy, showed a time-dependent decline in muscle strength by 2 months of intervention. In contrast, KPC mice fed a KD, either alone or combined with chemotherapy, significantly maintained muscle strength after 2 months. To elucidate potential mechanisms underlying the beneficial effects of a KD in maintaining muscle strength, we initially examined, in gastrocnemius muscle, the activation state of mTOR signaling. The phosphorylated levels of S6 ribosomal protein (p-S6), a downstream target of mTOR, were increased in gastrocnemius isolated from KPC mice fed a KD, compared to CD-fed mice. Conclusions Our findings indicate that KD maximizes and preserves motor function strength during PDA progression and enhances median survival when combined with chemotherapy. Additional studies are underway to evaluate the mechanisms of how KD improves and preserves muscle strength in PDA. Funding Sources Research Support: Startup funds and a University of California Comprehensive Cancer Center award to GGM. NEC is supported with a fellowship from UC-MEXUS.

Synthetic High-density Lipoprotein Nanodiscs for Personalized Immunotherapy Against Gliomas.

Gliomas are brain tumors with dismal prognoses. The standard-of-care treatments for gliomas include surgical resection, radiation, and temozolomide administration; however, they have been ineffective in providing significant increases in median survival. Antigen-specific cancer vaccines and immune checkpoint blockade may provide promising immunotherapeutic approaches for gliomas. We have developed immunotherapy delivery vehicles based on synthetic high-density lipoprotein (sHDL) loaded with CpG, a Toll-like receptor-9 agonist, and tumor-specific neoantigens to target gliomas and elicit immune-mediated tumor regression. We demonstrate that vaccination with neoantigen peptide-sHDL/CpG cocktail in combination with anti-PD-L1 immune checkpoint blocker elicits robust neoantigen-specific T-cell responses against GL261 cells and eliminated established orthotopic GL261 glioma in 33% of mice. Mice remained tumor free upon tumor cell rechallenge in the contralateral hemisphere, indicating the development of immunologic memory. Moreover, in a genetically engineered murine model of orthotopic mutant IDH1 (mIDH1) glioma, sHDL vaccination with mIDH1 neoantigen eliminated glioma in 30% of animals and significantly extended the animal survival, demonstrating the versatility of our approach in multiple glioma models. Overall, our strategy provides a general roadmap for combination immunotherapy against gliomas and other cancer types.

Therapeutic Efficacy of 213Bi-labeled sdAbs in a Preclinical Model of Ovarian Cancer.

Targeted alpha-particle therapy (TAT) might be a relevant therapeutic strategy to circumvent resistance to conventional therapies in the case of HER2-positive metastatic cancer. Single-domain antibody fragments (sdAb) are promising vehicles for TAT because of their excellent in vivo properties, high target affinity, and fast clearance kinetics. This study combines the cytotoxic α-particle emitter bismuth-213 (213Bi) and HER2-targeting sdAbs. The in vitro specificity, affinity, and cytotoxic potency of the radiolabeled complex were analyzed on HER2pos cells. Its in vivo biodistribution through serial dissections and via Cherenkov and micro-single-photon emission computed tomography (CT)/CT imaging was evaluated. Finally, the therapeutic efficacy and potential associated toxicity of [213Bi]Bi-DTPA-2Rs15d were evaluated in a HER2pos tumor model that manifests peritoneal metastasis. In vitro, [213Bi]Bi-DTPA-2Rs15d bound HER2pos cells in a HER2-specific way. In mice, high tumor uptake was reached already 15 min after injection, and extremely low uptake values were observed in normal tissues. Co-infusion of gelofusine resulted in a 2-fold reduction in kidney uptake. Administration of [213Bi]Bi-DTPA-2Rs15d alone and in combination with trastuzumab resulted in a significant increase in median survival. We describe for the very first time the successful labeling of an HER2-sdAb with the α-emitter 213Bi, and after intravenous administration, revealing high in vivo stability and specific accumulation in target tissue and resulting in an increased median survival of these mice especially in combination with trastuzumab. These results indicate the potential of [213Bi]Bi-DTPA-sdAb as a new radioconjugate for TAT, alone and as an add-on to trastuzumab for the treatment of HER2pos metastatic cancer.

Preclinical Targeted α- and β--Radionuclide Therapy in HER2-Positive Brain Metastasis Using Camelid Single-Domain Antibodies.

HER2-targeted therapies have drastically improved the outcome for breast cancer patients. However, when metastasis to the brain is involved, current strategies fail to hold up to the same promise. Camelid single-domain antibody-fragments (sdAbs) have been demonstrated to possess favorable properties for detecting and treating cancerous lesions in vivo using different radiolabeling methods. Here we evaluate the anti-HER2 sdAb 2Rs15d, coupled to diagnostic γ- and therapeutic α- and β−-emitting radionuclides for the detection and treatment of HER2pos brain lesions in a preclinical setting. 2Rs15d was radiolabeled with 111In, 225Ac and 131I using DTPA- and DOTA-based bifunctional chelators and Sn-precursor of SGMIB respectively and evaluated in orthotopic tumor-bearing athymic nude mice. Therapeutic efficacy as well as systemic toxicity were determined for 131I- and 225Ac-labeled sdAbs and compared to anti-HER2 monoclonal antibody (mAb) trastuzumab in two different HER2pos tumor models. Radiolabeled 2Rs15d showed high and specific tumor uptake in both HER2pos SK-OV-3-Luc-IP1 and HER2pos MDA-MB-231Br brain lesions, whereas radiolabeled trastuzumab was unable to accumulate in intracranial SK-OV-3-Luc-IP1 tumors. Administration of [131I]-2Rs15d and [225Ac]-2Rs15d alone and in combination with trastuzumab showed a significant increase in median survival in 2 tumor models that remained largely unresponsive to trastuzumab treatment alone. Histopathological analysis revealed no significant early toxicity. Radiolabeled sdAbs prove to be promising vehicles for molecular imaging and targeted radionuclide therapy of metastatic lesions in the brain. These data demonstrate the potential of radiolabeled sdAbs as a valuable add-on treatment option for patients with difficult-to-treat HER2pos metastatic cancer.

Poly(ethylene glycol)-Poly(beta-amino ester)-Based Nanoparticles for Suicide Gene Therapy Enhance Brain Penetration and Extend Survival in a Preclinical Human Glioblastoma Orthotopic Xenograft Model.

Glioblastoma (GBM) is the most devastating brain cancer, and cures remain elusive with currently available neurosurgical, pharmacological, and radiation approaches. While retrovirus- and adenovirus-mediated suicide gene therapy using DNA encoding herpes simplex virus-thymidine kinase (HSV-tk) and prodrug ganciclovir has been suggested as a promising strategy, a nonviral approach for treatment in an orthotopic human primary brain tumor model has not previously been demonstrated. Delivery challenges include nanoparticle penetration through brain tumors, efficient cancer cell uptake, endosomal escape to the cytosol, and biodegradability. To meet these challenges, we synthesized poly(ethylene glycol)-modified poly(beta-amino ester) (PEG-PBAE) polymers to improve extracellular delivery and coencapsulated plasmid DNA with end-modified poly(beta-amino ester) (ePBAE) polymers to improve intracellular delivery as well. We created and evaluated a library of PEG-PBAE/ePBAE nanoparticles (NPs) for effective gene therapy against two independent primary human stem-like brain tumor initiating cells, a putative target to prevent GBM recurrence. The optimally engineered PEG-PBAE/ePBAE NP formulation demonstrated 54 and 82% transfection efficacies in GBM1A and BTIC375 cells respectively, in comparison to 37 and 66% for optimized PBAE NPs without PEG. The leading PEG-PBAE NP formulation also maintained sub-250 nm particle size up to 5 h, while PBAE NPs without PEG showed aggregation over time to micrometer-sized complexes. The comparative advantage demonstrated in vitro successfully translated into improved in vivo diffusion, with a higher amount of PEG-PBAE NPs penetrating to a distance of 2 mm from the injection site. A significant increase in median survival from 53.5 to 67 days by PEG-PBAE/pHSV-tk NP and systemic ganciclovir treatment compared to a control group in orthotopic murine model of human glioblastoma demonstrates the potential of PEG-PBAE-based NPs as an effective gene therapy platform for the treatment of human brain tumors.

Combination immunotherapy and radiotherapy causes an abscopal treatment response in a mouse model of castration resistant prostate cancer

BackgroundProstate cancer is poorly responsive to immune checkpoint inhibition, yet a combination with radiotherapy may enhance the immune response. In this study, we combined radiotherapy with immune checkpoint inhibition (iRT) in a castration-resistant prostate cancer (CRPC) preclinical model.MethodsTwo Myc-CaP tumor grafts were established in each castrated FVB mouse. Anti-PD-1 or anti-PD-L1 antibodies were given and one graft was irradiated 20 Gy in 2 fractions.ResultsIn CRPC, a significant increase in survival was found for radiation treatment combined with either anti-PD-1 or anti-PD-L1 compared to monotherapy. The median survival for anti-PD-L1 alone was 13 days compared to 30 days for iRT (p = 0.0003), and for anti-PD-1 alone was 21 days compared to 36 days for iRT (p = 0.0009). Additional treatment with anti-CD8 antibody blocked the survival effect. An abscopal treatment effect was observed for iRT in which the unirradiated graft responded similarly to the irradiated graft in the same mouse. At 21 days, the mean graft volume for anti-PD-1 alone was 2094 mm3 compared to iRT irradiated grafts 726 mm3 (p = 0.04) and unirradiated grafts 343 mm3 (p = 0.0066). At 17 days, the mean graft volume for anti-PD-L1 alone was 1754 mm3 compared to iRT irradiated grafts 284 mm3 (p = 0.04) and unirradiated grafts 556 mm3 (p = 0.21). Flow cytometry and immunohistochemistry identified CD8+ immune cell populations altered by combination treatment in grafts harvested at the peak effect of immunotherapy, 2–3 weeks after starting treatment.ConclusionsThese data provide preclinical evidence for the use of iRT targeting PD-1 and PD-L1 in the treatment of CRPC. Immune checkpoint inhibition combined with radiotherapy treats CPRC with significant increases in median survival compared to drug alone: 70% longer for anti-PD-1 and 130% for anti-PD-L1, and with an abscopal treatment effect.PrecisCastration-resistant prostate cancer in a wild-type mouse model is successfully treated by X-ray radiotherapy combined with PD-1 or PD-L1 immune checkpoint inhibition, demonstrating significantly increased median overall survival and robust local and abscopal treatment responses, in part mediated by CD8 T-cells.

Combined hepatocellular-cholangiocarcinoma: a population level analysis of incidence and mortality trends

BackgroundThe purpose of this study was to explore trends in incidence, incidence-based (IB) mortality, and survival for combined hepatocellular-cholangiocarcinoma (cHCC-CC) utilizing a population-based database to attract people’s attention to this disease.MethodsThe Surveillance, Epidemiology, and End Results (SEER) database was utilized to investigate the incidence and IB mortality for cHCC-CC from 2000 to 2014. Trends in age-adjusted incidence and IB mortality were characterized by the Joinpoint Regression program. The Kaplan-Meier method and log-rank test were utilized to implement survival analyses. Cox regression was utilized to estimate independent predictors of mortality.ResultsThe incidence of cHCC-CC was 0.26 per 1,000,000 individuals in 2000 and 0.59 per 1,000,000 individuals in 2014, with an annual percent change (APC) (i.e., the extent of increase in incidence) of 3.84% (95% confidence interval [CI] 1.7–6.1; P < 0.05). The IB mortality also displayed a sustained increase (APC was 4.59%, 95% CI 1.9–7.4; P < 0.05). Compared to patients not undergoing surgery, patients undergoing surgical treatment experienced a significant increase in median survival (3 vs. 28 months; P < 0.001). However, the median survival decreased in patients with tumor size > 5 cm (20 vs. 9 months; P < 0.001). Based on univariate Cox regression analysis, African-American race, distant stage, regionalized stage, tumor size ≥ 5 cm, and no surgery were risk factors for death.ConclusionsWe identified an overall steady increase in the incidence of cHCC-CC, which indicates that primary prevention strategies for cHCC-CC have not improved much in recent years and that cHCC-CC needs to be taken seriously.

STEM-22. UPTAKE OF P-BORONO-PHENYLALANINE BY BRAIN TUMOR STEM LIKE CELLS ANALYZED BY MASS CYTOMETRY

INTRODUCTION Because of chemo- and radio-resistance of brain tumor stem cells, they could be the origins of recurrent malignant glioma. We have used boron neutron capture therapy (BNCT) to treat patients with either recurrent or newly diagnosed malignant glioma resulting in a significant increase in median survival of patients. BNCT is a form of tumor-selective particle radiation therapy consisting of two components. First, a boron-10 (10B)-containing drug is administered, followed by irradiation with epithermal neutrons. The resulting 10B(n,α)7Li capture reaction produces alpha particles whose short path length (5–9 µm) results in the selective killing of tumor cells with a concomitant sparing of adjacent normal tissues. P-borono-phenylalanine (BPA) is a chemical compound used in clinical trials in BNCT. BPA accumulates preferentially in growing cells rather than in quiescent cells of the tumor. Here, we investigate whether brain tumor stem like cells take up BPA or not using mass cytometry (Cytof).

Beta-Blocking Colorectal Cancer

Introduction: Colorectal cancer (CRC) is the third leading cause of cancer death in the United States. Recent observational studies have shown a correlation between beta blockers (BB) and improved survival rates in certain types of malignancies. A proposed mechanism of action was decreased production of vascular endothelial growth factor when suppressing adrenergic activity. This pathway is commonly seen in patients with CRC. A most recent study showed that prognosis was not affected by the use of BB in patients with all stages of CRC, however, there was an overall survival benefit seen when looking specifically at stage IV patients who were on BB. In this study, we further investigate the role of BB in patients with stage IV CRC based on their molecular profile. Methods: This is a retrospective analysis of 949 patients diagnosed with stage IV CRC from 1996 to 2017 who were treated at MD Anderson Cancer Center. The primary endpoint of this study was median survival based on BB use and molecular status. The patients were subcategorized into their BRAF, RAS, and BRAF/RAS wild type(WT) status. Further information such as demographics, mutation status, location of tumor burden, and smoking status was also collected. The cox regression model and kaplan-meier curves were used in the statistical analysis. Results: The RAS/BRAF WT group was the only group to have a statistically significant difference in median survival. Of the 312 patients, patients who were on BB had a significant increase in median survival compared to patients who were not on BB (53 months vs. 43 months, p=0.022). Within this group, we further analyzed the median survival in patients using selective versus nonselective versus no BB. Patients who used nonselective BB had a 62 month median survival rate versus 48 months and 43 months for selective BB usage and non BB usage respectively (p=0.044). Conclusion: In summary, while we did not see a benefit of BB usage in our overall cohort of patients with metastatic CRC, specific subgroups of these patients did benefit from BB usage. Patients who had RAS/BRAF WT mutations were found to have improved survival outcomes with BB usage, particularly with nonselective BB. We believe that these findings warrant additional studies in order to further assess the benefit of non selective BB combined with targeted therapy in this subgroup of stage IV CRC.

Abstract 4801: Potential of mebendazole as an anti-tumor agent for adenoid cystic carcinoma and other rare cancers

Abstract Adenoid Cystic Carcinoma (ACC) is a rare adenocarcinoma arising most commonly in the major and minor salivary glands of the head and neck. Despite a deepening understanding of the molecular events that lead to sustained tumor growth, there are currently no approved therapies for ACC or many other rare cancers. Repurposing of drugs for use in oncology is of increasing interest to promote the rapid development of new therapies and address the significant unmet medical need that remains for rare cancers. The FDA-approved anti-helminthic drug mebendazole (MBZ) has been identified as an agent that can affect several cancer relevant pathways involved in tumor growth and metastasis. Anti-tumor effects of MBZ include G2/M cell cycle arrest leading to apoptosis, inhibition of the IGF1R/AKT pathway, and induction of MYB degradation by the proteasome. Based on this biology, several rare cancer tumor cell lines including neuroblastoma, rhabdomyosarcoma and Ewing sarcoma, were analyzed for sensitivity to MBZ treatment in vitro. Cultured cells were exposed to increasing concentrations of MBZ and viability was measured after 72hours. Treatment with MBZ resulted in a significant decrease in cell viability with IC50s ranging from 0.05-1 μM suggesting that MBZ may represent a potent anti-cancer agent for several rare cancer indications. Identification of therapies for ACC has been hampered by the lack of ACC cell lines and transgenic mouse models. To circumvent these issues, in collaboration with the ACC Research Foundation, the activity of MBZ was tested in several ACC patient-derived xenograft (PDX) models. Mice were implanted subcutaneously with PDX tumors and treatment was initiated when tumors reached a size of 125-300 mm3. Mice were randomized into three treatment groups to receive daily treatment with vehicle or MBZ at either 50 or 200 mg/kg for the duration of the study. Daily oral dosing with MBZ was well tolerated with no overt toxicities. Significant anti-tumor activity was observed in 2 out of 3 ACC PDX models. In the most aggressive ACCX9 PDX model, MBZ showed statistically significant anti-tumor activity at the highest dose of 200 mg/kg resulting in a significant increase in median survival compared to vehicle-treated mice (38 vs 29.5 days respectively, p=0.0013). Inhibition of tumor growth was also observed in the less aggressive ACCX6 PDX model at both the 50 and 200 mg/kg dose levels compared to vehicle and was accompanied by an increase in median survival (95.5 and 64.5 days vs 42 days respectively; p=0.0085 and p=0.083). In the reportedly more refractory ACCX5M1 PDX model, treatment with MBZ did not inhibit tumor growth. Overall, the in vitro and in vivo results suggest that MBZ potentially represents a novel therapeutic option for the treatment of rare cancers including ACC. Citation Format: Jamie Dempsey Barber, Mahta Samizadeh, Nannan Jia, William Siders, Johanne Kaplan. Potential of mebendazole as an anti-tumor agent for adenoid cystic carcinoma and other rare cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4801.

Tethering of Chemotherapeutic Drug/Imaging Agent to Bile Acid-Phospholipid Increases the Efficacy and Bioavailability with Reduced Hepatotoxicity.

Weakly basic drugs display poor solubility and tend to precipitate in the stomach's acidic environment causing reduced oral bioavailability. Tracing of these orally delivered therapeutic agents using molecular probes is challenged due to their poor absorption in the gastrointestinal tract (GIT). Therefore, we designed a gastric pH stable bile acid derived amphiphile where Tamoxifen (as a model anticancer drug) is conjugated to lithocholic acid derived phospholipid (LCA-Tam-PC). In vitro studies suggested the selective nature of LCA-Tam-PC for cancer cells over normal cells as compared to the parent drug. Fluorescent labeled version of the conjugate (LCA-Tam-NBD-PC) displayed an increased intracellular uptake compared to Tamoxifen. We then investigated the antitumor potential, toxicity, and median survival in 4T1 tumor bearing BALB/c mice upon LCA-Tam-PC treatment. Our studies confirmed a significant reduction in the tumor volume, tumor weight, and reduced hepatotoxicity with a significant increase in median survival on LCA-Tam-PC treatment as compared to the parent drug. Pharmacokinetic and biodistribution studies using LCA-Tam-NBD-PC witnessed the enhanced gut absorption, blood circulation, and tumor site accumulation of phospholipid-drug conjugate leading to improved antitumor activity. Therefore, our studies revealed that conjugation of chemotherapeutic/imaging agents to bile acid phospholipid can provide a new platform for oral delivery and tracing of chemotherapeutic drugs.

Abstract 704: Therapeutic potential of Delta24-ACT, a novel immunostimulatory oncolytic adenovirus, for the treatment of pediatric solid tumors: Initial study in pHGG, DIPG and osteosarcoma

Abstract Pediatric High Grade Glioma (pHGG), including Diffuse Intrinsic Pontine Glioma (DIPG), and osteosarcoma are amongst the most common and lethal pediatric solid tumors. Despite improvements in surgery, radiotherapy and chemotherapy, the outcome for children affected with these malignancies remains dismal since the current treatments are ineffective and inflict severe side effects. Thus, it is critical to implement novel and radically different therapeutic approaches to improve the survival and quality of life of these children. Delta24 is a modified adenovirus with a tumor dependent replication, and its antitumor effect has been tested in preclinical and clinical models of both high grade glioma and osteosarcoma. The adenovirus destroys the tumor mass as it replicates within the tumor. Additionally, the adenovirus infection triggers the recruitment of lymphocytes to the tumor. However, tumors are often characterized by an immunosuppressive environment that hampers the synergistic effect mediated by the virus and the immune system. Here we describe the generation of a new oncolytic adenovirus Delta24-ACT, based on the Delta24 platform, encoding an immunostimulatory protein. For this project we used relevant immunocompetent pediatric solid models. The toxicity of the virus was assessed by dose-escalation experiments. Delta24-ACT was well tolerated and did not lead to important adverse effects. The antitumor effect of Delta24-ACT was evaluated in immunocompetent mice bearing orthotopic supratentorial glioma, DIPG or local osteosarcoma that spontaneously metastasize to lungs, obtaining significant tumor shrinkage or complete elimination in some of them. Delta24-ACT also promoted an increased T-cell infiltration within the tumor and an enhanced antitumor immune response. Of importance, treatment with Delta24-ACT led to a significant increase in median survival in all the tumor models tested and resulted in long-term survivors free of disease. Furthermore, in our osteosarcoma model local treatment of primary tumors led to the regression of spontaneous lung metastases, which are usually the leading cause of death in most of the patients affected by osteosarcoma. Currently, we are performing re-challenge experiments to evaluate a possible memory effect mediated by the virus and mechanistic studies to elucidate the mechanism of action. Altogether, these results demonstrate the potential therapeutic benefit of Delta24-ACT adenovirus in the treatment of pediatric solid tumors such as pHGG, DIPG and osteosarcoma, representing an important milestone in the fight against cancer. Citation Format: Marc Garcia Moure, Naiara Martínez-Vélez, Enric Xipell, Marisol González-Huarriz, Ana Patiño, Oren J. Becher, Cande Gómez-Manzano, Juan Fueyo, Marta M. Alonso. Therapeutic potential of Delta24-ACT, a novel immunostimulatory oncolytic adenovirus, for the treatment of pediatric solid tumors: Initial study in pHGG, DIPG and osteosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 704. doi:10.1158/1538-7445.AM2017-704