Improvement Of Antitumor Efficacy Research Articles

Abstract 4039: Enhanced anti-cancer efficacy of the AhR Inhibitor DA-4505 in combination with anti-PD-1 treatment: Attenuation of lung metastasis and elimination of tumor

Abstract Background: The Aryl hydrocarbon receptor (AhR) is one of the most predominant regulators of cancer metabolism. AhR plays a crucial role in inhibiting the activation of immune cells and promoting the growth of tumor cells. Here, we propose that a best-in-class AhR inhibitor, DA-4505, improves anti-tumor efficacy in combination with anti-PD-1. Methods: To explore the anti-tumor effects, DA-4505 was administered at a daily dose of 10 mg/kg either alone or in combination with anti-PD-1 (10 mg/kg) in a syngeneic mouse model. Tumor volume, survival rates, and metastasis were measured, and immune profiles were evaluated using mIHC, flow cytometry, and scRNAseq. Results: The synergistic anti-tumor effects of the DA-4505 and aPD-1 combination therapy were observed across four mouse tumor models (CT26, 4T1, LLC, TC1). The combination group demonstrated a significant improvement in anti-tumor efficacy compared to the monotherapy groups. Despite the moderate response of aPD-1 in the CT26 colon tumor model, the combination group displayed heightened anti-tumor effects through increase in CD8 T cell activity (P<0.05). In the LLC and TC1 lung cancer models, the combination therapy demonstrated improved anti-tumor effects and survival rates (P<0.001). Notably, the LLC model exhibited a significant increase in M1-type macrophages, while the TC1 model showed a significant augmentation in functional markers of CD3+ T cells within the combination group (P<0.05). In both models, there was a significant reduction in the ratio of immunosuppressive M-MDSC and PMN-MDSC in the combination group. Immune depletion assays elucidated that DA-4505 mediated anti-tumor effects by increase in CD8+ T cells, NK cells, and macrophages in the CT26 model. In contrast, the LLC model exhibited the contribution of macrophages and CD4+ T cells to anti-tumor effects in the combination group (P<0.05). To assess the impact on metastasis inhibition, an orthotopic model of 4T1 mouse tumor was established, revealing a significantly increased anti-tumor effects and survival rate in the combination group, accompanied by a reduced lung metastasis ratio. H&E staining confirmed diminished migration of tumor tissue to adjacent areas. scRNAseq analysis of CT26 tumor samples indicated consistent changes at the gene expression level, reflecting a decrease in metastasis-related MMP and VEGF genes in the combination group and an increasing trend in cytotoxicity-related genes following DA-4505 treatment. Conclusion: The AhR inhibitor, DA-4505, has demonstrated enhanced anti-tumor efficacy when administered in combination with anti-PD-1. Furthermore, it not only promoted tumor elimination but also demonstrated significant efficacy in inhibiting metastasis. This study highlights the potential of combining AhR inhibitors with immunotherapies for clinical treatment. Citation Format: Dong Kwon Kim, Sujeong Baek, Seung Min Yang, Young Taek Kim, Joon Yeon Hwang, Seul Lee, Seong-san Kang, Mi hyun Kim, Heekyung Han, Kwangmin Na, Chai Young Lee, Yu Jin Han, Taedong Han, Hyounmie Doh, Jongho Cho, Dajeong Kim, Daewon Cha, Jae Hwan Kim, Youngseon Byeon, Young Seob Kim, Mi Ran Yun, Jii Bum Lee, Min Hee Hong, Sun Min Lim, Kyoung-Ho Pyo, Byoung Chul Cho. Enhanced anti-cancer efficacy of the AhR Inhibitor DA-4505 in combination with anti-PD-1 treatment: Attenuation of lung metastasis and elimination of tumor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4039.

Combined immunochemotherapy achieving targeted co-delivery of chlorogenic acid and doxorubicin by sialic acid-modified liposomes enhances anti-cancer efficacy.

Malignant melanoma is a high-grade aggressive skin tumor with an increasing incidence and mortality rates worldwide. Chemotherapeutic drugs such as doxorubicin have limited efficacy against melanoma due to their poor sensitivity, severe side effects, and drug resistance. Recent studies have shown that combinations of immunotherapy and chemotherapy have a synergistic effect in enhancing the anti-tumor effect. Here, we have developed liposomes co-loaded with chlorogenic acid (CA) and doxorubicin (DOX), modified with sialic acid-octadecylamine conjugate (SA-ODA), designated CA-DOX-SAL, that facilitate drug delivery by recognizing Siglec-1 receptor on TAMs. The physicochemical studies revealed the particle size and zeta potential of CA-DOX-SAL as 128.3 ± 0.8 nm and - 4.33 ± 0.50 mV, respectively. In vitro, CA-DOX-SAL demonstrated robust cellular uptake through SA receptor-mediated tumor-associated macrophages (TAM) targeting and exerted greater cytotoxicity on tumor cells. In vivo, targeted liposomes were found to accumulate in the tumor area, leading to an improvement in anti-tumor efficacy. In addition, CA-DOX-SAL effectively inhibited B16F10 melanoma tumor growth by stimulating the transition from tumor-promoting M2-type to anti-tumor M1-type and directly killing tumor cells. Overall, the co-delivery of immunomodulatory CA and chemotherapeutic DOX presents a promising therapeutic strategy to enhance clinical outcomes in the treatment of melanoma.

Enhancing the Anti-tumor Potency of a Novel Siglec-15 Antibody by Engineering its Fc-mediated Effector Functions.

Siglec-15, an inhibitory immune checkpoint, is an emerging target in cancer immunotherapy. Blocking the function of Siglec-15 is an excellent strategy for cancer treatment and antibody blockade has been used to target Siglec-15. However, whether Fc-mediated effector functions contribute to the therapeutic effect of antibodies remains unclear. Herein, we generated a monoclonal antibody, 1-15D1, which had a high binding affinity with Siglec-15 and strongly activated T-cell immune response in vitro. Subsequently, the Fc-mediated effector functions of 1-15D1 were explored in a Siglec-15 humanized mouse model, and further improvement in antitumor efficacy was observed in the mouse IgG2a isotype group. Thus, we demonstrate that the antitumor effects of 1-15D1 were mediated via multiple factors. In addition to the T-cell immune response, 2 novel mechanisms were explored, including the internalization of the cell surface Siglec-15 and Fc-mediated effector functions. In conclusion, our studies not only provide a potential agent for the improvement of cancer immunotherapy but also suggest that a specific role of Fc-mediated immune regulation may improve the therapeutic potency of Siglec-15 monoclonal antibody.

Application of a novel multicomponent nanoemulsion to tumor therapy Based on the theory of “unification of drugs and excipients”

Toad skin has many pharmacological activities and bufadienolides are regarded as its main anti-tumor components. The poor water solubility, high toxicity, rapid elimination and less selectivity in vivo of bufadienolides limit the application of toad skin. Based on the “unification of drugs and excipients” theory, the toad skin extracts (TSE) and Brucea javanica oil (BJO) nanoemulsions (NEs) were designed to solve the aforementioned problems. BJO as the main oil phase was not only used to prepare the NEs, but played a synergistic therapeutic role combined with TSE. TSE-BJO NEs showed 155 nm particle size, entrapment efficiency of >95% and good stability. TSE-BJO NEs demonstrated superior anti-tumor activity compared with the TSE or BJO NEs alone. The mechanism of TSE-BJO NEs to enhance the antineoplastic efficacy involved several pathways, such as inhibiting cell proliferation, inducing tumor cell apoptosis >40% and arresting cell cycle at G2/M. TSE-BJO NEs could co-deliver drugs into the target cells efficiently and exhibit satisfying synergism. Besides, TSE-BJO NEs facilitated the long circulation of bufadienolides contributing to the high accumulation of drugs at tumor sites and the improvement of anti-tumor efficacy. The study achieves the combinative administration of the toxic TSE and BJO with high efficacy and safety.

Abstract 5107: A novel AhR inhibitor ‘DA-4505’ improved the anti-cancer efficacy of surgical and chemotherapy via synergistic anti-tumor effects of aPD-1

Abstract Background: The Aryl hydrocarbon receptor (AhR) is one of the most predominant regulators of cancer metabolism. The AhR exerts important immunosuppressive functions by activating Treg cells and myeloid-derived suppressor cells and repressing CD8+ effector T cells. Here, we propose that a best-in-class AhR inhibitor, DA-4505, improves anti-tumor efficacy via modulation of tumor immune surveillance compared to BAY2416964, an AHR antagonist drug candidate being studied in the clinical phase. Methods: To evaluate anti-tumor effects of DA-4505 and BAY2416964, the two AhR inhibitors were dosed at 10 mg/kg once daily alone or in combination with aPD-1 (10 mg/kg) in surgical and chemotherapy models, and a PDX model (YHIM2004). Tumor volume, relapse, and survival were evaluated, and immune profiles were analyzed with IHC, flow cytometry, and scRNAseq. Results: A significant tumor reduction appeared in the CT26 and 4T1 tumor models after the DA-4505 treatment compared to vehicle group (P<0.05). In contrast, DA-4505 treatment did not induce significant tumor regression compared to vehicle group in tumor-bearing NOG mice, suggesting that anti-tumor effects of DA-4505 were driven by immunologic mechanisms. To evaluate the role of DA-4505 in conjunction with surgery, DA-4505 alone or in combination with anti-PD-1 was given prior to and following resection of the tumors in 4T1 tumor-bearing mice. Survival of mice treated with DA-4505 alone or DA-4505 combined with anti-PD-1 was significantly prolonged after resection compared to aPD-1 treatment group (P<0.05). In addition, there were four mice that did not have a relapse by treating DA-4505 with or without aPD-1 after surgery (4/5). A tumor regression also appeared in the YHIM2004-engrafted humanized mouse study. A tumor reduction was shown by treating DA-4505 alone or in combination with pembrolizumab compared to vehicle group (P<0.05). Next, we co-administered an AhR inhibitor and aPD-1 as a partner to improve the antitumor effects of chemotherapy. The DA-4505 add-on group showed tumor regression when compared with the combination therapy group treated with aPD-1 and chemotherapy (P<0.0001). In addition, a significant increase in survival rate was shown in the group treated with a DA-4505 add-on compared to vehicle group (P<0.001). Analysis of scRNAseq showed that M1 macrophage expressing CCL7 and CCL8 were increased in DA-4505 treated group compared to the vehicle and aPD-1 groups. This suggests that immune modulatory effect of DA-4505 may be due to enhanced recruitment of immune cells into the tumor site by macrophages with high chemotactic activity. Conclusion: The AhR inhibitor DA-4505 demonstrated an improvement in anti-tumor efficacy. In addition, it has shown a synergistic effect when combined with aPD-1. Discoveries from this study provide a preclinical rationale for future clinical implications in solid tumor. Citation Format: DongKwon Kim, Sujeong Baek, Seung Min Yang, Yu Jin Han, Seong-san Kang, Chun-Bong Synn, Mi Hyun Kim, Heekyung Han, Kwangmin Na, Young Taek Kim, Sungwoo Lee, Taedong Han, Hyounmie Doh, Jongho Cho, Dajeong Kim, Daewon Cha, Jae Hwan Kim, Youngseon Byeon, Young Seob Kim, Mi Ran Yun, Ji Yun Lee, Jii Bum Lee, Chang Gon Kim, Min Hee Hong, Sun Min Lim, Byoung Chul Cho, Kyoung-Ho Pyo. A novel AhR inhibitor ‘DA-4505’ improved the anti-cancer efficacy of surgical and chemotherapy via synergistic anti-tumor effects of aPD-1. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5107.

Abstract 4099: Dual targeting of tumor cells and cancer associated fibroblasts enhances CAR T efficacy in solid tumors

Abstract CAR T cell therapies have demonstrated considerable potency in treating hematologic cancers, but only limited efficacy in eliminating solid tumors. One reason for this discrepancy may derive from the immunologic and physical barriers created by infiltration of cancer associated fibroblasts (CAFs) into solid tumors. These CAFs, which can comprise 15-85% of the stromal cells in a tumor mass, are correlated with poor patient survival and can reduce CAR T cell efficacies by secreting immunosuppressive cytokines, stimulating tumor cell proliferation, and depositing fibrotic barriers to CAR T cell penetration. Here, we are pursuing a method to suppress or eliminate CAF activities in the tumor microenvironment (TME). A potential CAR T cell target that is uniquely expressed on CAF surfaces is fibroblast activation protein (FAP). In this study, we have employed a novel, highly specific FAP targeting small molecule to direct our universal CAR T cells to CAFs. For this purpose, we have designed a CAR that contains an otherwise classical CAR except the extracellular scFv specifically binds fluorescein. Upon addition of a bispecific adaptor comprised of fluorescein linked via a short spacer to our FAP ligand, a bridge is formed between the anti-fluorescein CAR on the T cell and FAP on the CAF, resulting in formation of an immunologic synapse between the CAR T cell and CAF that triggers CAF destruction and CAR T cell proliferation. Importantly, this CAR T cell design also permits simultaneous administration of a second bispecific adaptor (i.e. fluorescein linked via a short spacer to a cancer-specific ligand) that can enable the same CAR T cell to concurrently kill adjacent cancer cells. To test whether this universal CAR T cell can eliminate both cancer cells and CAFs, we have implanted KB cells (i.e. a cell line that creates an immunologically “cold” folate receptor (FR) expressing solid tumor) into NSG mice and quantitated the CAR T cell’s toxicity in the presence of one or both bispecific adapters. While administration of the universal CAR T cells followed by intravenous injection of an FR-targeting bispecific adaptor achieved significant anti-tumor efficacy, co-injection of a FAP-targeted bispecific adaptor enhanced this efficacy without apparent toxicity. Analyses of tumor masses from the therapy further revealed that co-administration of the FAP-targeted bispecific adaptor not only promoted CAF elimination but also enhanced CAR T infiltration and activation. Importantly, a similar improvement in anti-tumor efficacy could be readily demonstrated in a second immunologically “cold” PSMA-expressing solid tumor model. Taken together, we conclude that the bispecific adaptor/universal CAR T approach offers a unique opportunity to concurrently eradicate cancer cells and tumor-supporting CAFs in a manner that can improve the overall performance of the CAR T cells in solid tumors. Citation Format: Bo Huang, Suilan Zheng, Haiyan Chu, Ramesh Mukkamala, Suresh K. Bowroju, Yashapal Singh, Sudarsan R. Kasireddy, Md Sazzadul Bari, Madduri Srinivasarao, Laurie Beitz, Byoung Ryu, Michael Jensen, Andrew M. Scharenberg, Philip S. Low. Dual targeting of tumor cells and cancer associated fibroblasts enhances CAR T efficacy in solid tumors. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4099.

Liposome Formulation of Carfilzomib with Improved Activity As a Monotherapy and in Combination with Vinblastine

Introduction: Carfilzomib (CFZ) is an epoxyketone-based irreversible proteasome inhibitor that is one of the leading treatments for multiple myeloma (MM). Cardiotoxicity is the primary limitation for the clinical use of CFZ. We developed a novel liposome nanoparticle formulation of CFZ, a compound with low water solubility (<5 µg/mL) and low pKa (5.14) (LS-CFZ) that dramatically reduces the toxicity, increases the plasma half-life, and improves the antitumor efficacy compared to the commercial formulation. In addition, CFZ was combined in the same liposome, with vinblastine (VBL) an autophagy inhibitor. The combination exhibited synergistic anti-tumor cell activity in vitro and in vivo using a colon cancer (C26) mouse tumor model. Methods: CFZ was screened for cytotoxicity in combination with various cell lines including MM and C26 with a focus on autophagy inhibitors. VBL was co-loaded into the same liposomes with CFZ, and also loaded into separate particles. Formulations with various lipids, trapping agents and drug to lipid ratios were screened for drug loading efficiency. The lead formulation was selected based on mouse plasma half-life after IV injection in male CD1 mice. The plasma concentration of CFZ, VBL and a fluorescent lipid (liposome) label (DiIC18(5)) were measured by HPLC. The dose ratio of the CFZ and VBL was by determined by the MTD in tumor-free mice and the optimum dose and ratio was used for the efficacy study. The lead formulations were evaluated for anti-tumor efficacy in the C26 colon cancer using a single treatment (day 1) when the tumor volume was 200 mm3 for all liposome formulations and two treatments (day 1 and day 2) (optimum for CFZ) for the unencapsulated CFZ and VBL. Results: Cytotoxicty studies in C26 cells indicated the optimum ratio of CFX/VBL was between 5:1 and 20:1. All liposomes used had a diameter of 110-130 nm. Ammonium sucrose octasulfate yielded the longest retention of CFZ and VBL in the liposome after IV injection in mice. The best lipid composition was sphingomyelin/Cholesterol/PEG-2000-PE (55/45/2.8, mol/mol/mol) with a particle size of 110-130 nm in diameter. Cryo TEM images of the LS-CFZ show a dense amorphous mass of drug precipitate in the center of the liposomes. The drug to lipid ratio chosen for use in the efficacy study was 101 g/mol lipid for CFZ and 103 g/mol lipid for VBL with a loading efficiency >90%. Using the optimized trapping agent and lipid composition the %ID of CFZ is nearly identical to that of the liposome carrier up to 6 h; an average of 98.4±5.4% of the drug is retained up to 6 h. The %ID of CFZ decreases below that of the liposome between 6 and 24 h and most (>98%) of the CFZ has been released from the liposomes by the 24 h point. The AUC for LS-CFZ (2 mg/kg) is 1584 fold higher than CFZ administered as SBCD-CFZ (sulfobutyl cyclodextrin formulated, Kyprolis®) (5 mg/kg). CFZ administered as SBCD-CFZ has a t1/2 of 0.2 h compared to 3.0 h for LS-CFZ. VBL had slightly better stability than CFZ with a plasma half-life of 4.9 h. LS-CFZ had single dose MTD of 30 mg/kg for L-CFZ, while SBCD-CFZ given QDx2 had an MTD 6 mg/kg. The dramatic decrease in toxicity is likely due to lower Cmax of the bioavailable CFZ and reduced cardiotoxicity. The increased tolerability of LS-CFZ allowed for a CFZ/VBL ratio of 20:1 (18/0.9 mg/kg, CFZ/VBL) for the liposome formulation; the unencapsulated CFZ and VBL were administered at a ratio of 5:1 (5/1 mg/kg, CFZ/VBL). The anti-tumor efficacy of LS-CFZ/VBL combination was far superior to all other treatments. LS-CFZ was nearly identical to LS-VBL, and both single agents had more activity than any unencapsulated drug. As a monotherapy, LS-CFZ was far more efficacious than SBCD-CFZ, which is commonly used for treatment of multiple myeloma patients. Conclusion: Liposome formulation of CFZ increased the tolerability by 5-fold compared to the commercial CFZ formulation. The described liposome technology enables significant improvement in anti-tumor efficacy for CFZ as a monotherapy or in combination against a C26 mouse model. The improved activity in solid tumors warrants investigation of LS-CFZ for MM treatment. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Photothermally responsive theranostic nanocomposites for near-infrared light triggered drug release and enhanced synergism of photothermo-chemotherapy for gastric cancer.

Near-infrared (NIR) photothermal therapy plays a critical role in the cancer treatment and diagnosis as a promising carcinoma treatment modalities nowadays. However, development of clinical application has been greatly limited due to the inefficient drug release and low tumor accumulation. Herein, we designed a NIR-light triggered indocyanine green (ICG)-based PCL core/P(MEO2MA-b-HMAM) shell nanocomposites (PPH@ICG) and evaluated their therapeutic effects in vitro and in vivo. The anticancer drug 5-fluorouracil (5Fu) and the photothermal agent ICG were loaded into a thermo-sensitive micelle (PPH@5Fu@ICG) by self-assembly. The nanoparticles formed were characterized using transmission electron microscopy, dynamic light scattering, and fluorescence spectra. The thermo-sensitive copolymer (PPH@5Fu@ICG) showed a great temperature-controlled drug release response with lower critical solution temperature. In vitro cellular uptake and TEM imaging proved that PPH@5Fu@ICG nanoparticles can home into the lysosomal compartments under NIR. Moreover, in gastric tumor-bearing nude mice, PPH@5Fu@ICG + NIR group exhibited excellent improvement in antitumor efficacy based on the NIR-triggered thermo-chemotherapy synergy, both in vitro and in vivo. In summary, the proposed strategy of synergistic photo-hyperthermia chemotherapy effectively reduced the 5Fu dose, toxic or side effect, which could serve as a secure and efficient approach for cancer theranostics.

Combination microRNA-based cellular reprogramming with paclitaxel enhances therapeutic efficacy in a relapsed and multidrug-resistant model of epithelial ovarian cancer

Most advanced-stage ovarian cancer patients, including those with epithelial ovarian cancer (EOC), develop recurrent disease and acquisition of resistance to chemotherapy, leading to limited treatment options. Decrease in Let7b miRNA levels in clinical ovarian cancer has been associated with chemoresistance, increased proliferation, invasion, and relapse in EOC. We have established a murine EOC relapsed model by administering paclitaxel (PTX) and stopping therapy to allow for tumor regrowth. Global microRNA profiling in the relapsed tumor showed significant downregulation of Let7b relative to untreated tumors. Here, we report the use of hyaluronic acid (HA)-based nanoparticle formulation that can deliver Let7b miRNA mimic to tumor cells and achieve cellular programming both in vitro and in vivo. We demonstrate that a therapeutic combination of Let7b miRNA and PTX leads to significant improvement in anti-tumor efficacy in the relapsed model of EOC. We further demonstrate that the combination therapy is safe for repeated administration. This novel approach of cellular reprogramming of tumor cells using clinically relevant miRNA mimic in combination with chemotherapy could enable more effective therapeutic outcomes for patients with advanced-stage relapsed EOC.

Designed improvement to T-cell immunotherapy by multidimensional single cell profiling

BackgroundAdoptive cell therapy based on the infusion of chimeric antigen receptor (CAR) T cells has shown remarkable efficacy for the treatment of hematologic malignancies. The primary mechanism of action of...

Poly (ethyl 2-cyanoacrylate) nanoparticles (PECA-NPs) as possible agents in tumor treatment.

Tumor eradication has many challenges due to the difficulty of selectively delivering anticancer drugs to malignant cells avoiding contact with healthy tissues/organs. The improvement of antitumor efficacy and the reduction of systemic side effects can be achieved using drug loaded nanoparticles. In this study, poly (ethyl 2-cyanoacrylate) nanoparticles (PECA-NPs) were prepared using an emulsion polymerization method and their potential for cancer treatment was investigated. The size, polydispersity index and zeta potential of prepared nanoparticles are about 80 nm, 0.08 and -39.7 mV, respectively. The stability test shows that the formulation is stable for 15 days, while an increase in particle size occurs after 30 days. TEM reveals the spherical morphology of nanoparticles; furthermore, FTIR and 1H NMR analyses confirm the structure of PECA-NPs and the complete polymerization. The nanoparticles demonstrate an in vitro concentration-dependent cytotoxicity against human epithelial colorectal adenocarcinoma cell lines (Caco-2), as assessed by MTT assay. The anticancer activity of PECA-NPs was studied on 3D tumor spheroids models of hepatocellular carcinoma (HepG2) and kidney adenocarcinoma cells (A498) to better understand how the nanoparticles could interact with a complex structure such as a tumor. The results confirm the antitumor activity of PECA-NPs. Therefore, these systems can be considered good candidates in tumor treatment.

Abstract 5782: Selumetinib-based therapy in uveal melanoma patient-derived xenografts

Abstract Purpose: The prognosis of metastatic uveal melanoma (UM) patients remains one of the worst observed in human cancers. The identification of frequently mutated GNAQ/GNA11 and the activation of MAPK signaling in UM raise the possibility of using efficient targeted therapies such as MEK inhibition. The aim of our study was to evaluate drug combinations that might enhance the efficacy of the MEK inhibitor, selumetinib (AZD6244, ARRY-142886), using patient-derived xenografts. Materials: Five UM PDXs were used in this study, i.e., MP34, MP46, MP55, MP77, and MM26, all mutated for GNAQ or GNA11. Selumetinib was administered alone or combined with chemotherapies (dacarbazine and docetaxel) or targeted therapies: the ERK inhibitor, AZ6197 and the mTORC1/2 inhibitor, vistusertib (AZD2014). All targeted therapies were administered orally five days/week at the following doses: selumetinib at 25 mg/kg/day BID, AZ6197 at 50 mg/kg QD, AZD2014 at 15mg/kg QD. Dacarbazine was administered at 40 mg/kg for 5 consecutive days every 28 days and docetaxel at 15 mg/kg weekly. Both were administered intraperitoneally. Results: The combination of selumetinib and dacarbazine did not show improvement of antitumor efficacy in MP34, MM26 and MP55.The results showed a slight increase of overall response rate when selumetinib was combined with docetaxel, in comparison to the treatment with selumetinib or docetaxel alone. Importantly, we observed a significant antitumor effect when selumetinib was used in combination with AZ6197 or AZD2014 with respect to the monotherapies. Preliminary pharmacodynamics studies showed variation of the expression of p-ERK and also p-AKT and/or p-S6 when UM PDX were treated with AZ6197 or AZD2014 alone or in combination with selumetinib. Conclusion: Our data suggest that ERK and mTORC1/2 targeting could represent promising therapeutic approaches for the treatment of metastatic UM patients. Citation Format: Didier Decaudin, Rania EL Botty, Béré Diallo, Gerald Massonnet, Justine Fleury, Adnan Naguez, Marine Dubois, Emma J. Davies, Aaron Smith, Joanne Wilson, Colin Howes, Paul Smith, Nathalie Cassoux, Pascale Mariani, Sophie Piperno-Neumann, Sergio Roman Roman, Fariba Nemati. Selumetinib-based therapy in uveal melanoma patient-derived xenografts [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 5782.

Improved Photodynamic Cancer Treatment by Folate-Conjugated Polymeric Micelles in a KB Xenografted Animal Model.

Photodynamic therapy (PDT) is a light-induced chemical reaction that produces localized tissue damage for the treatment of cancers and various nonmalignant conditions. In the clinic, patients treated with PDT should be kept away from direct sunlight or strong indoor lighting to avoid skin phototoxicity. In a previous study, it was demonstrated that the skin phototoxicity of meta-tetra(hydroxyphenyl)chlorin (m-THPC), a photosensitizer used in the clinic, can be significantly reduced after micellar encapsulation; however, no improvement in antitumor efficacy was observed. In this work, a folate-conjugated polymeric m-THPC delivery system is developed for improving tumor targeting of the photosensitizer, preventing photodamage to the healthy tissue, and increasing the effectiveness of the photosensitizers. The results demonstrate that folate-conjugated m-THPC-loaded micelles with particle sizes around 100 nm are taken up and accumulated by folate receptor-overexpressed KB cells in vitro and in vivo, and their PDT has no significant adverse effects on the body weight of mice. After an extended delivery time, a single dose of folate-conjugated m-THPC-loaded micelles has higher antitumor effects (tumor growth inhibition = 92%) through inhibition of cell proliferation and reduction of vessel density than free m-THPC or m-THPC-loaded micelles at an equivalent m-THPC concentration of 0.3 mg kg(-1) after irradiation. Furthermore, folate-conjugated m-THPC-loaded micelles at only 0.2 mg kg(-1) m-THPC have a similar antitumor efficacy to m-THPC or m-THPC-loaded micelles with the m-THPC concentration at 0.3 mg kg(-1) , which indicates that the folate conjugation on the micellar photosensitizer apparently reduces the requirement of m-THPC for PDT. Thus, folate-conjugated m-THPC-loaded micelles with improved selectivity via folate-folate receptor interactions have the potential to reduce, not only the skin photosensitivity, but also the drug dose requirement for clinical PDT.

Agonist anti-GITR antibody significantly enhances the therapeutic efficacy of Listeria monocytogenes-based immunotherapy

BackgroundWe previously demonstrated that in addition to generating an antigen-specific immune response, Listeria monocytogenes (Lm)-based immunotherapy significantly reduces the ratio of regulatory T cells (Tregs)/CD4+ and myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment. Since Lm-based immunotherapy is able to inhibit the immune suppressive environment, we hypothesized that combining this treatment with agonist antibody to a co-stimulatory receptor that would further boost the effector arm of immunity will result in significant improvement of anti-tumor efficacy of treatment.MethodsHere we tested the immune and therapeutic efficacy of Listeria-based immunotherapy combination with agonist antibody to glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR) in TC-1 mouse tumor model. We evaluated the potency of combination on tumor growth and survival of treated animals and profiled tumor microenvironment for effector and suppressor cell populations.ResultsWe demonstrate that combination of Listeria-based immunotherapy with agonist antibody to GITR synergizes to improve immune and therapeutic efficacy of treatment in a mouse tumor model. We show that this combinational treatment leads to significant inhibition of tumor-growth, prolongs survival and leads to complete regression of established tumors in 60% of treated animals. We determined that this therapeutic benefit of combinational treatment is due to a significant increase in tumor infiltrating effector CD4+ and CD8+ T cells along with a decrease of inhibitory cells.ConclusionTo our knowledge, this is the first study that exploits Lm-based immunotherapy combined with agonist anti-GITR antibody as a potent treatment strategy that simultaneously targets both the effector and suppressor arms of the immune system, leading to significantly improved anti-tumor efficacy. We believe that our findings depicted in this manuscript provide a promising and translatable strategy that can enhance the overall efficacy of cancer immunotherapy.

Development of a multi-target peptide for potentiating chemotherapy by modulating tumor microenvironment

Finding effective cures against aggressive malignancy remains a major challenge in cancer chemotherapy. Here, we report a "tadpole"-like peptide by covalently conjugating the alanine-alanine-asparagine "tail" residual to the cyclic tumor homing peptide iRGD (CCRGDKGPDC) to afford nRGD, which significantly enhanced tumoricidal effects of doxorubicin, by either co-administered as a physical mixture or as a targeting ligand covalently conjugated to the liposomal carrier. Given twice at an equivalent dose of 5mg/kg, doxorubicin loaded liposomes modified with nRGD (nRGD-Lipo-Dox) showed excellent antitumor efficacy in 4T1 breast cancer mice, of which 44.4% remained alive for over 90 days without recurrence during the period of investigation. The dramatic improvement in antitumor efficacy was attributed to nRGD-Lipo-Dox which appeared to specifically interact with tumor vascular endothelial cells to achieve efficient tumor penetration, and modulate tumor microenvironment with depletion of tumor associated macrophages.

Improvement of Antitumor Efficacy by Combination of Thermosensitive Liposome with High-Intensity Focused Ultrasound.

High intensity focused ultrasound (HIFU), allowing for precise heating of the deep and local area, is emerging as the source of mild hyperthermia for delivery of doxorubicin (DOX) using thermosensitive liposomes (TSLs). Conventionally, HIFU has been used for intravascular drug release at tumor tissue by inducing mild hyperthermia immediately upon systemic administration of DOX-TSLs. This immediate heating approach (IHA), however, limits the deep penetration of DOX for high anticancer efficacy. In an attempt to maximize the accumulation of DOX at tumor, the delayed heating approach (DHA) has been explored. In this approach, DOX-TSLs were intravenously administered into the tumor-bearing mice after pre-treatment of tumor tissue with HIFU to increase vascular permeability. We developed the fatty acid-cojugated elastinlike polypeptide bearing TSL (FTSL). The DOX-loaded FTSLs had a hydrodynamic size of 142 nm. In vivo biodistribution study demonstrated that DOX-FTSLs were selectively accumulated at tumor tissue with the maximum amount of DOX at 6 h post-injection. Thereafter, the tumor tissue was heated to 42 °C to induce rapid release of DOX from FTSLs. The results have demonstrated that, compared to IHA, DHA significantly enhances the antitumor efficacy of DOX-FTSLs because of their effective penetration to tumor tissue via the enhanced permeation retention effect, followed by rapid release of DOX.

419. Efficacy of Rambo for Sarcoma Therapy

Soft Tissue Sarcoma (STS), a cancer which forms in the connective tissue, requires aggressive treatment. Metastatic soft tissue sarcomas are associated with a median prognosis of about twelve months accompanied frequently with many signs and symptoms leading to a poor quality of life. These tumors frequently have angiogenic properties. Angiogenesis is responsible for the formation of new blood vessels and is associated with local progression and increased metastatic disease. Strategies that work to block angiogenesis are currently being investigated as a treatment for STS. Oncolytic virus therapy is a novel treatment strategy that utilizes modified viruses to specifically replicate and lyse cancer cells. The combination of angiogenesis inhibitors with oncolytic virus treatment has not been tested for STS. Here we tested the effect of combining oncolytic viral therapy with antiangiogenic gene therapy. RAMBO is a HSV-1 derived oncolytic virus that codes for the production of Vstat120, a gene with potent antiangiogenic effects. We have tested a panel of sarcoma cells and shown effective infection and lysis of these cells by RAMBO and HSVQ-1 in vitro. In vivo, we compared the antitumor efficacy of RAMBO and HSVQ-1 against sarcoma tumors grown in mice. Briefly, mice were implanted with 150-300mm3 A673 sarcoma tumors were injected with a PBS, HSVQ-1, or RAMBO (5.5×106 pfu). Mice were followed for tumor size over a period of time. Tumor volumes over time were logarithm (base 2) transformed for variance stabilization. The linear mixed model was used to compare the three groups while accounting for the variance-covariance structure due to repeated measures at different days from the same mouse. Statistically significant improvement in antitumor efficacy was observed in RAMBO treated tumors, compared to HSVQ-1 and control. H&E staining of tumor tissue reveals large areas of necrosis in RAMBO treated tumors. RAMBO and its inherent antiangiogenic gene therapy demonstrated significant efficacy in these sarcoma models and further investigations are underway with combination therapeutic strategies.

5-Aminolevulinic acid-loaded fullerene nanoparticles for in vitro and in vivo photodynamic therapy.

This report explores some properties of 80-200nm nanoparticles containing 5-aminolevulinic acid (ALA) and fullerene (C60) for photodynamic therapy (PDT). Compared with ALA, the nanoparticles yielded more protoporphyrin IX (PpIX) formation in cells and tissues and to a significant improvement in antitumor efficacy in tumor-bearing mice. Maximum levels of PpIX were obtained 4h after administration and selective PpIX formation in tumor was observed. These nanoparticles appear to be a useful vehicle for drug delivery purposes. In this study, a procedure for preparing fullerene nanoparticles containing ALA was developed. The product alone exhibited no detectable toxicity in the dark and was superior to ALA alone in promoting PpIX biosynthesis and PDT efficacy both in culture and in a murine tumor model. These results suggest that this procedure could be the basis for an improved PDT protocol for cancer control.

Combinational Delivery of Hydrophobic and Hydrophilic Anticancer Drugs in Single Nanoemulsions To Treat MDR in Cancer

In this study, we developed the core-matched nanoemulsions (NEs) functionalized by vitamin E (VE) and tocopherol poly(ethylene glycol)succinate (TPGS) to codeliver hydrophobic and hydrophilic drugs, paclitaxel (PTX) and 5-fluoroucacil (5-FU), in order to achieve synergistic effects and overcome PTX resistance in a multi-drug-resistant (MDR) human epidermal carcinoma cell line KB-8-5. Antitumor effect of the combination therapy based on core-matched technology (CMT) was evaluated in vitro and in vivo in mice. The core-matched NEs showed entrapment efficiency of >90% and were of nanoscale particle size and negative zeta-potential. The combined core-matched NEs exhibited concentration and time-dependent cytotoxicity against PTX-sensitive KB-3-1 cells and PTX-resistant KB-8-5 cells as well as an obviously increased G2/M phase block. The improvements in therapeutic response over either PTX–VE or 5-FU–TPGS therapy alone were demonstrated by the ability to effectively induce the apoptosis of tumor cells via up-regulation of tumor suppressor p53 and β-tubulin and by the significant inhibition of cell cycle progression. The combination therapy led to dramatic inhibition of tumor growth with little toxicity in vivo, especially in the PTX-resistant KB-8-5 tumors, whereas Taxol had little therapeutic effect. This was mainly ascribed to the synergism of PTX and 5-FU and the reverse of MDR by the inhibition of ATPase activity by VE and TPGS. Coencapsulation of two chemotherapeutic agents with different mechanisms allows simultaneous interruption of diverse anticancer pathways, resulting in increased therapeutic response and low toxicity. The CMT markedly facilitated the long circulation of PTX and 5-FU, which was closely associated with the high accumulation of chemotherapeutic agents within the tumors and the improvement of antitumor efficacy. The current study demonstrated the feasibility of incorporating PTX and 5-FU targeting to different pathways into a single core-matched NE for the reversal of MDR and synergism in cancer therapy.

What Is the Role of Stem-Cell Transplantation for Follicular Non-Hodgkin Lymphoma in the Rituximab Era?

Defining the best treatment for follicular lymphoma (FL) is still a challenge, partly because the available treatment options are often associated with prolonged overall survival (OS) as a result of the long natural history of this disease. Many clinical studies have used progression-free survival (PFS) as their end point but suffer from insufficient follow-up or lack of statistical power to assess OS, which is the indisputably best end point. Until the introduction of rituximab, standard chemotherapy (varying from low-dose oral chlorambucil to intensive multidrug schedules) was effective in producing responses but did not result in a survival benefit. The introduction of autologous peripheral-blood stem-cell transplantation with its inherent low morbidity and mortality in comparison with autologous bone marrow transplantation resulted in three trials applying high-dose therapy as first-line treatment for FL. All these studies showed an improvement of antitumor efficacy, but none had a significant impact on OS. This is most likely the result of the inability to select patients who might benefit most from this procedure or, again, insufficient follow-up. Patients who experience relapse, especially early relapse, have shown that they have a lymphoma with a clinically less benign behavior. In this patient population, several phase II studies suggested an improved survival, which was confirmed by the only randomized study in relapsed FL that showed a significantly improved OS in patients who underwent transplantation as compared with standard chemotherapy. Several authors have described a relatively high incidence of myelodysplasia, attributed to the high-dose therapy. However, this may also be the result of extensive pretreatment, suggesting that high-dose therapy might be of greater benefit earlier in the treatment course, as opposed to after multiple relapses. After the introduction of rituximab, several groups chose to investigate whether OS was improved with the incorporation of rituximab in standard-dose, first-line treatment of FL. The general conclusion is that PFS was improved in all, but OS was prolonged in only some, of these trials. Likewise, incorporating rituximab into highdose chemotherapy as part of first-line therapy resulted in better PFS but an OS benefit was observed in only one such trial. In the article that accompanies this editorial, Pettengel et al describe the results of the randomized European Group for Blood and Marrow Transplantation (EBMT) LYM-1 study. Rituximab-naive patients with relapsed chemosensitive FL were randomly assigned to analyze the efficacy of in vivo purging and maintenance therapy with rituximab in combination with high-dose therapy and autologous stem-cell transplantation. In 7 years, 280 patients were included. The authors conclude that in vivo purging did not improve outcome; however, maintenance therapy did improve PFS, but not OS at the time of this report. This study was not designed to assess the value of high-dose therapy because all patients received this treatment, which the authors considered standard therapy in relapsed FL. Although an important observation, it is important to realize that the patients in the EBMT LYM-1 study all were rituximab naive, which limits conclusions on current applicability. In addition, from the French Collaborative Trial in Relapsed Aggressive Lymphoma (CORAL) study, we have learned that the results of high-dose therapy in patients with diffuse large B-cell lymphoma who experience relapse after first-line rituximab-containing therapy are significantly inferior, especially in the situation of an early relapse. Whether this is also the case in FL is an open question, but data from another French study in FL may be reassuring that this is not necessarily the case in FL. We can conclude that high-dose therapy changes the natural behavior of FL in relapsed disease and, probably, also in first-line therapy if PFS is a convincing end point. However, it is not clear that PFS is the best end point in FL. How can we improve the outlook for patients with FL? One approach is to wait for the current studies to mature and report OS data. Alternative options are new and more effective monoclonal antibodies or monoclonals conjugated to either radionuclides or toxins. Currently, there are no randomized data in support of these expensive options. Is allogeneic transplantation the panacea? Although complicated by a high treatment-related mortality (TRM), myeloablative transplants resulted in convincing evidence of cure in patients for whom other intensive therapies had failed. With the introduction of nonmyeloablative transplants, the decreased TRM resulted in better outcomes, even in patients who had previously undergone autograft. The high TRM after allografting in comparison with autografting limits its role in first-line salvage. It remains to be seen whether tandem transplantation combining the efficacy of highdose therapy with the immunological graft versus lymphoma effect will lead to the desired more favorable outcome. JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L VOLUME 31 NUMBER 13 MAY 1 2013