LMD-07. In Vitro AND In Vivo Culture of Patient Derived-Cerebral Spinal Fluid-Circulating Tumor Cells (PD-CSF-CTCs) in Leptomeningeal Disease (LMD) From Melanoma to Identify Novel Treatment Strategies

Background Approximately 5% of melanoma patients (pts) will develop LMD. Currently there is no effective treatments for this disease. A significant barrier to the development of effective therapies has been the inability to culture CSF-CTCs for functional analysis. For the first time, we were able to successfully expand CSF-CTCs in vitro and in vivo. We assessed gene signatures of PD-CSF-CTCs to determine novel targets for therapy. As a proof of concept, we tested the efficacy of combining ceritinib (cer), an IGF-1R inhibitor and trametinib (tra), a MEK inhibitor, against LMD. Methods CSF from 11 pts were collected from various sources (ie: LPs, Ommayas, rapid autopsies). PD-CSF-CTCs were expanded in vitro in conditioned media and in vivo using cell line-derived xenograft model. Single-cell RNA-sequencing (scRNAseq) analysis was performed to assess transcriptional profiles of PD-CSF-CTCs. Results Of the total 61 PD-CSF-CTCs collected from 11 pts (avg: 4.07 CSF collections/patient), we successfully cultured PD-CSF-CTCs from 3 pts (20%) and were able to grow them in vivo from 2 pts (18%). scRNAseq identified IGF-1R, Sox9, ErbB3 and MLANA were among the enriched genes for PD-CSF-CTCs. IGF-1R inhibition by cer and depletion by CRISPR suppressed cell growth. We evaluated the responses of cer + tra treatment in vitro and found that combining these agents produced drug synergy against PD-CSF-CTCs and resensitized BRAF inhibitor-resistant melanoma cell line, WM164R. In vivo LMD xenograft model showed cer + tra treatment significantly prolonged median survival of PD-CSF-CTCs LMD (control: 27 days vs treatment: 38.5 days; P value < 0.032) and WM164R LMD (control: 35 days vs treatment: MS not reached; P value < 0.047). Conclusions Though the sample size is small, this is the first report of the successful in vitro and in vivo culture of CSF-CTCs from pts with LMD.

TMOD-02. IN VITRO & IN VIVO CULTURE OF PATIENT DERIVED (PD) CSF-CTCS IN LEPTOMENINGEAL DISEASE (LMD) FROM MELANOMA TO IDENTIFY NOVEL TREATMENT STRATEGIES

BACKGROUND Approx. 5% of melanoma pts develop LMD. There are essentially no models of LMD available for therapeutic development. A significant barrier to the development of effective therapies against LMD has been the inability to culture and expand LMD cells. Here we report our strategies to in vitro & in vivo culturing of CSF-CTCs. As a proof of concept, we assessed response to Ceritinib (Cer), a non-canonical IGF1R inhibitor) in combination with MEK inhibitor. METHODS We collected CSF from 11 patients (pts) from various sources (ie: LPs, Ommayas, autopsies). 3 pts CSF were collected at autopsies. PD-CSF-CTCs were expanded in vitro in conditioned media and in vivo using CDX model. scRNAseq analysis was performed to assess expression profiles of PD-CSF-CTCs. RESULTS AND DISCUSSION Of the total 61 PD-CSF-CTCs collected from 11 pts (avg: 4.07 CSF collections/patient), we successfully cultured PD-CSF-CTCs from 3 pts (20%) and were able to grow them in vivo from 2 pts (18%). scRNAseq analysis identified MLANA, IGF1R, SOX9 and ErbB3 were among genes highly expressed in our PD-CSF-CTCs. We evaluated the responses of the combination Cer with MEKi (Tra) in vitro and in vivo and found that these agents produced therapeutic effects to both established melanoma cell lines and our PD-CSF-CTCs. For example, in vivo testing showed a median survival (MS): 18, 35, and 27 days in WM164, WM164R and the PD-CSF-CTCs, respectively, in control groups. Whereas treatment with Cer + Tra produced significantly better MS in all three in vivo models and was not reached in WM164, WM164R (p< 0.001 & p< 0.047, respectively) and 38.5 days in PD-CSF-CTCs (p< 0.032). CONCLUSIONS Though the sample size is small, this is the first report of the successful in vitro & in vivo culture of CSF-CTCs from pts with LMD.

CMET-26. IN-VITRO & IN-VIVO CULTURE OF PATIENT (PT) DERIVED CSF-CTCS IN LEPTOMENINGEAL DISEASE (LMDZ) FROM MELANOMA TO IDENTIFY NOVEL TREATMENT STRATEGIES

BACKGROUND Approx. 5% of melanoma pts develop LMDz. There are essentially no models of LMDz available for therapeutic development. Here we report, the in-vitro & in-vivo culturing of CSF-CTCs. METHODS CSF-CTCs were detected by the Veridex CellSearch® System. Cell-free DNA and cell-associated DNA were extracted, sequenced and profiled. Expanded ex-vivo CSF-CTCs were grown in-vitro and tested for drug sensitivity. CSF-CTCs were grown successfully in-vivo from 1 pt; labeled human Braf V600E WM164 cells were injected IT in as a control. RESULTS CSF-CTCs: 12 LMDz pts and 8 melanoma pts without LMDz were studied. All but 1 LMDz pts (92%) had CSF-CTCs (avg: 2148.6; range 23 - 3055 CTCs/ml). In contrast, 3/8 (37%) melanoma Brain Mets pts without LMDz had CSF-CTCs but fewer of them (avg: 0.31; range 0.13 - 0.6 CTCs/ml CSF). CSF-CTCs Profile: These had BrafV600E (83%), and GNAQ Q209P & NRAS Q61R in 1 pt each. Ex-vivoculture of CSF-CTCs and PDX model: After lengthy optimization of conditions we successfully expanded CSF-CTCs in vitro(~25% of pts), and in-vivo in immunodeficient mice from 1 pt (~10% of samples). Ceritinib, used as a FAK inhibitor, with MEKi was effective in-vitro (p=3.17e-6) and prolonged survival in-vivo in LMDz (median survival: >32 days vs control: 18 days; p=7.81e-5). CONCLUSIONS Though the sample size is small, this is the first report of the successful in-vitro & in-vivo culture of CSF-CTCs from pts with LMDz. Single cell analysis to determine how representative these models are and further in-vivo testing are in progress.

LPTO-03. IN-VITRO & IN-VIVO CULTURE OF PATIENT (PT) DERIVED CSF-CTCs IN LEPTOMENINGEAL DISEASE (LMDz) FROM MELANOMA TO IDENTIFY NOVEL TREATMENT STRATEGIES

BACKGROUND: Approximately 5% of melanoma pts develop LMDz. There are essentially no models of LMDz available for therapeutic development. Here we report, the in-vitro & in-vivo culturing of CSF-CTCs. METHODS: CSF-CTCs were detected by the Veridex CellSearch® System. Cell-free DNA and cell-associated DNA were extracted, sequenced and profiled. Expanded ex-vivo CSF-CTCs were grown in-vitro and tested for drug sensitivity. CSF-CTCs were grown successfully in-vivo from 1 pt; labeled human Braf V600E WM164 cells were injected IT in as a control. RESULTS: CSF-CTCs: 12 LMDz pts and 8 melanoma pts without LMDz were studied. All but 1 LMDz pts (92%) had CSF-CTCs (avg: 2148.60; range 23 - 3055 CTCs/ml). In contrast, 3/8 (37%) melanoma Brain Mets pts without LMDz had CSF-CTCs but fewer of them (avg: 0.31; range 0.13 - 0.6 CTCs/ml CSF). CSF-CTCs Profile: These had BrafV600E (83%), and GNAQ Q209P & NRAS Q61R in 1 pt each. Ex-vivo culture of CSF-CTCs and PDX model: After lengthy optimization of conditions we successfully expanded CSF-CTCs in-vitro (~25% of pts), and in-vivo in immunodeficient mice from 1 pt (~10% of samples). Ceritinib, used as a FAK inhibitor, with MEKi was effective in-vitro (p=3.17e-6) and prolonged survival in-vivo in LMDz (median survival: >32 days vs control: 18 days; p=7.81e-5). CONCLUSIONS: Though the sample size is small, this is the first report of the successful in-vitro & in-vivo culture of CSF-CTCs from pts with LMDz. Single cell analysis to determine how representative these models are and further in-vivo testing are in progress.

MENGENAL SISTEM GNOTOBIOTIK DAN PERANANNYA PADA BUDIDAYA BIOTA LAUT

INTRODUCTION TO GNOTOBIOTICS AND ITS ROLE IN MARICULTURE. Initial colonization of microbial community in marine larvae is one of the important stage in larval development in terms of subsequent growth, immunostimulation, and pathogen elimination. Gearing towards environmentally sustainable manner of aquaculture, early microbial manipulation in larval stage may provide an alternative in efficient and productive larviculture. One of the tool to further study the host-microbe interaction is through in-vivo culture of axenic and gnotobiotic larvae, in which a germ-free larvae was produced, and subsequently induced with single strain benign microbe to observe its response and characteristics. Several methods and protocols to obtain axenic-gnotobiotic condition is highlighted, along with the current development of gnotobiotic research, particularly in commercially valuable saltwater fish, e.g. Atlantic cod and European seabass. The development of novel gnotobiotic protocols combined with different scientific approach, e.g. gene expression, quorum sensing, immunostimulants, and purified diets may provide better insight in host-microbe interaction of marine biota, which in turn will benefit the implementation of specific probiotics, prebiotics, diets, and microbial regulation in marine larviculture.