Abstract 4565: Drug screening by layered 3D co-cultured tumor model including vascularized stromal tissue

Introduction: In vivo, tumor microenvironments consist of not only cancer cells but also extracellular matrix and stromal tissues, such as fibroblasts, blood vessels, and so on. The interactions between cancer cells and stromal tissue have been reported to affect the behavior of cancer cells. So that ex vivo model recapturing the tumor microenvironment is needed to evaluate the efficacy of drugs under the condition mimicking the patient tumor tissue. Here, we developed the unique tissue engineering technique, which easily enables the construction of cell - stacked three dimensional (3D) tissue, and co-culture of 3D stromal tissues and patient-derived cancer cells (PDCs). We investigated drug sensitivity in conventional 2D culture, our 3D co-cultured model and in vivo tumor.

Methods: Fibroblasts and vascular endothelial cells were suspended in a buffer solution containing heparin and collagen to support cell aggregation. The heparin/collagen-treated cells were seeded in culture-inserts in over-confluent manner, and 3D layered stromal tissue called were constructed. PDCs established from colorectal cancer (CRC) and non-small cell lung cancer (NSCLC) patients in the Cancer Institute Hospital of JFCR were co-cultured with the 3D stromal tissue. The 3D co-cultured model applied to drug screening, and the results were compared with those of 2D culture model. In vivo drug evaluations were performed with the compounds in which marked differences were observed between 2D and 3D models.

Results: In our 3D model, drug sensitivities to most of the tested compounds tended to be decreased in comparison with those in 2D culture condition. Interestingly, a part of drugs did not effective in 2D showed marked tumor growth inhibition in our 3D model. The compounds that showed favorable efficacy in 3D rather than 2D in multiple PDCs were accounted for about 5% of tested compounds. At least half of these drugs showed significant tumor growth suppression or tumor regression in vivo. On the contrary, in the case of drug sensitivities were considerably fallen in our 3D model, most of the evaluated compounds represented almost no anti-tumor effect in vivo. Results from gene and protein expression analyses supported that cancer cells co-cultured in our 3D stromal tissue have some similar profiles to in vivo tumor rather than 2D culture condition.

Conclusion: Our study proposed the unique 3D co-cultured tumor model. The model may enable more accurate drug screening reflecting the in vivo circumstances. Further studies are needed to confirm the model’s predictability of clinical outcomes.

Citation Format: Yuki Takahashi, Yumi Nomura, Yuma Yokokawa, Shiro Kitano, Satoshi Nagayama, Eiji Shinozaki, Ryohei Katayama, Naoya Fujita. Drug screening by layered 3D co-cultured tumor model including vascularized stromal tissue. [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 4565.

Injectable Prevascularized Mature Adipose Tissues (iPAT) to Achieve Long-Term Survival in Soft Tissue Regeneration

Soft tissue regeneration remains a challenge in reconstructive surgery. So far, both autologous fat implantations and artificial implants methods used in clinical applications lead to various disadvantages and limited lifespan. To overcome these limitations and improve the graft volume maintenance, reproducing a mature adipose tissue already including vasculature structure before implantation can be the solution. Therefore, injectable prevascularized adipose tissues (iPAT) are made from physiological collagen microfibers mixed with human mature adipocytes, adipose-derived stem cells, and human umbilical vein endothelial cells, embedded in fibrin gel. Following murine subcutaneous implantation, the iPAT show a higher cell survival (84% ± 6% viability) and volume maintenance after 3 months (up to twice heavier) when compared to non-prevascularized balls and liposuctioned fat implanted controls. This higher survival can be explained by the greater amount of blood vessels found (up to 1.6-fold increase), with balanced host anastomosis (51% ± 1% of human/mouse lumens), also involving infiltration by the lymphatic and neural vasculature networks. Furthermore, with the cryopreservation possibility enabling their later reinjection, the iPAT technology has the merit to allow noninvasive soft tissue regeneration for long-term outcomes.

Biomacromolecule-Fueled Transient Volume Phase Transition of a Hydrogel

A metabolic cycle-inspired hydrogel which exhibits the biomacromolecule-fueled transient volume phase transition is reported. This hydrogel has the affinity and digestive capacity for a fuel α-poly-L-lysine by incorporating acrylic acid and trypsin. The hydrogel captured fuel and transiently shrank owing to the construction of electrostatic cross-linkages. This process was inherently connected with the digestion of these cross-linkages and the release of oligo-lysine as waste, which induced the reswelling of the hydrogel at equilibrium. The transient volume change of the hydrogel realized the fuel-stimulated transient release of a payload. This study provides a strategy for engineering materials with biomacromolecule-fueled dynamic functions under the out-of-equilibrium condition.

Abstract 6027: Layered 3D co-cultured tumor model including vascularized stromal tissue may reflect drug sensitivities in vivo tumor

Background: Multiple 3D culture models have been reported as a superior tumor model than 2D culture. The importance of interaction between cancer and stromal cells has been widely recognized in tumor progression and resistance to treatment. Therefore, ex vivo model recapturing the tumor microenvironment is needed to evaluate the drug efficacy under the condition imitating the patient tumor tissue. Purpose: We developed a unique 3D co-cultured tumor model with stromal tissues containing a microvascular network. Here, we investigated drug sensitivity in conventional 2D culture, our 3D co-cultured model and in vivo tumor.

Methods: Drug sensitivity and gene expression on our model were evaluated using patient-derived cancer cells (PDC) established from colorectal cancer (CRC) patients in JFCR. The characteristics were compared with those of conventional 2D cultured cells or patient-derived xenograft (PDX).

Results: In our 3D model, the drug sensitivities tended to be decreased in comparison with those of 2D. However, some drugs presented potent efficacy in our 3D model rather than 2D, and such drugs showed significant tumor growth suppression or tumor regression in vivo. Transcriptome profiles of our 3D model showed relatively higher similarity to those of in vivo tumors than those of 2D.

Conclusion: Our study proposed the unique 3D co-cultured tumor model which may enable more accurate evaluation of drug sensitivities reflecting the in vivo circumstances.

Citation Format: Yuki Takahashi, Shiro Kitano, Eiji Shinozaki, Satoshi Nagayama, Ryohei Katayama, Naoya Fujita. Layered 3D co-cultured tumor model including vascularized stromal tissue may reflect drug sensitivities in vivo tumor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6027.

Constructing vascularized hepatic tissue by cell-assembled viscous tissue sedimentation method and its application for vascular toxicity assessment

In vitro Construction of the liver sinusoidal structure using artificial tissue is an important but worthwhile challenge, particularly for assessing the risk of diseases such as sinusoidal obstruction syndrome (SOS). Current models are unsuitable for evaluating the toxicity because of lacking sinusoidal capillary. In this study, we developed a vascularized hepatic tissue (VHT) using a unique tissue engineering technique, the cell assembled viscous tissue by sedimentation (CAViTs) method. The "viscous bodies" created using the CAViTs method exhibited significant self-assembly within 6 h after seeding, promoting cell-cell interaction. The level of albumin secreted by the VHT was four times higher than that of 2D-coculture and maintained for 1 month. The gene expression pattern of the VHT was closer to that of total human liver, compared with the 2D system. Quantitative evaluations of the vascular structure of VHT treated with two typical SOS-inducing compounds, monocrotaline and retrorsine, revealed higher sensitivity (IC₅₀ = 40.35 µM), 19.92 times higher than the cell-viability assay. Thus, VHT represents an innovative in vitro model that mimics the vessel network structure and could become a useful tool for the early screening of compounds associated with a risk of vascular toxicity. STATEMENT OF SIGNIFICANCE: Mimicking sinusoidal structures in in vitro liver model is important to consider from the perspective of predicting hepatotoxicity such like sinusoidal obstruction syndrome (SOS). However, it was difficult to reconstruct the vascular structure within the hepatocyte-rich environment. In this study, we constructed a vascularized hepatic tissue in a high-throughput manner by a unique method using collagen and heparin, and evaluated its applicability to toxicity assessment. Vessel morphology analysis of the model treated by monocrotaline, which is a well-known SOS-inducing compound, could predict the toxicity with higher sensitivity. To the best of our knowledge, this is the first report to provide vascularized hepatic tissues using sinusoidal endothelial cells at least for demonstrating applicability to the evaluation of SOS induction risk.

High-throughput drug screening models of mature adipose tissues which replicate the physiology of patients' Body Mass Index (BMI)

Obesity is a complex and incompletely understood disease, but current drug screening strategies mostly rely on immature in vitro adipose models which cannot recapitulate it properly. To address this issue, we developed a statistically validated high-throughput screening model by seeding human mature adipocytes from patients, encapsulated in physiological collagen microfibers. These drop tissues ensured the maintenance of adipocyte viability and functionality for controlling glucose and fatty acids uptake, as well as glycerol release. As such, patients' BMI and insulin sensitivity displayed a strong inverse correlation: the healthy adipocytes were associated with the highest insulin-induced glucose uptake, while insulin resistance was confirmed in the underweight and severely obese adipocytes. Insulin sensitivity recovery was possible with two type 2 diabetes treatments, rosiglitazone and melatonin. Finally, the addition of blood vasculature to the model seemed to more accurately recapitulate the in vivo physiology, with particular respect to leptin secretion metabolism.

Dynamic analysis of Porphyromonas gingivalis invasion into blood capillaries during the infection process in host tissues using a vascularized three-dimensional human gingival model

Porphyromonas gingivalis, the pathogen of periodontal disease, is thought to be involved in various diseases throughout the body via gingival tissue blood capillaries. However, the dynamic analysis of the infection mechanism, particularly the deep invasion process of the gingival tissue, has not yet been elucidated because of the lack of both in vivo and in vitro models. In this study, we developed a vascularized three-dimensional (3D) gingival model with an epithelial barrier expressing cell-cell junctions using collagen microfibers (CMFs) to enable the dynamic analysis of the P. gingivalis invasion process. Lipid raft disruption experiments in the gingival epithelial cell layer demonstrated that P. gingivalis migrates into the deeper epithelium via the intercellular pathway rather than intracellular routes. P. gingivalis was shown to invade the 3D gingival model, being found inside blood capillaries during two days of culture. Notably, the number of bacteria had increased greatly at least two days later, whereas the mutant P. gingivalis lacking the cysteine proteases, gingipains, showed a significantly lower number of survivors. The secretion of interleukin-6 (IL-6) from the gingival tissue decreased during the two days of infection with the wild type P. gingivalis, but the opposite was found for the mutant suggesting that P. gingivalis infection disturbs IL-6 secretion at an early stage. By allowing the dynamic observation of the P. gingivalis invasion from the epithelial cell layer into the blood capillaries for the first time, this model will be a powerful tool for the development of novel therapeutics against periodontal infection related diseases.

Engineered whole cut meat-like tissue by the assembly of cell fibers using tendon-gel integrated bioprinting

With the current interest in cultured meat, mammalian cell-based meat has mostly been unstructured. There is thus still a high demand for artificial steak-like meat. We demonstrate in vitro construction of engineered steak-like tissue assembled of three types of bovine cell fibers (muscle, fat, and vessel). Because actual meat is an aligned assembly of the fibers connected to the tendon for the actions of contraction and relaxation, tendon-gel integrated bioprinting was developed to construct tendon-like gels. In this study, a total of 72 fibers comprising 42 muscles, 28 adipose tissues, and 2 blood capillaries were constructed by tendon-gel integrated bioprinting and manually assembled to fabricate steak-like meat with a diameter of 5 mm and a length of 10 mm inspired by a meat cut. The developed tendon-gel integrated bioprinting here could be a promising technology for the fabrication of the desired types of steak-like cultured meats.

Bioprinted Vascularized Mature Adipose Tissue with Collagen Microfibers for Soft Tissue Regeneration

The development of soft tissue regeneration has recently gained importance due to safety concerns about artificial breast implants. Current autologous fat graft implantations can result in up to 90% of volume loss in long-term outcomes due to their limited revascularization. Adipose tissue has a highly vascularized structure which enables its proper homeostasis as well as its endocrine function. Mature adipocytes surrounded by a dense vascular network are the specific features required for efficient regeneration of the adipose tissue to perform host anastomosis after its implantation. Recently, bioprinting has been introduced as a promising solution to recreate in vitro this architecture in large-scale tissues. However, the in vitro induction of both the angiogenesis and adipogenesis differentiations from stem cells yields limited maturation states for these two pathways. To overcome these issues, we report a novel method for obtaining a fully vascularized adipose tissue reconstruction using supporting bath bioprinting. For the first time, directly isolated mature adipocytes encapsulated in a bioink containing physiological collagen microfibers (CMF) were bioprinted in a gellan gum supporting bath. These multilayered bioprinted tissues retained high viability even after 7 days of culture. Moreover, the functionality was also confirmed by the maintenance of fatty acid uptake from mature adipocytes. Therefore, this method of constructing fully functional adipose tissue regeneration holds promise for future clinical applications.

Abstract 322: A unique ex vivo tumor model: 3D co-cultured system with cancer cells and stromal tissue for drug evaluation

Background;Recently, three-dimensional culture model has been reported as better tumor model than 2D culture. The importance of interaction between cancer and stromal cells has been widely recognized in tumor progression and resistance against treatment. So that ex vivo model which recaptures the tumor microenvironment is required to perform drug evaluation mimicking the patient tumor tissue.

Methods; Layered 3D stromal tissues with microvascular network were produced by culturing normal fibroblasts and endothelial cells coated with the extra-cellular matrix (ECM) and natural polysaccharide, namely collagen and heparin. The layered 3D stromal tissues and co-cultured tumor were morphologically evaluated by HE staining, immunohistochemistry and immunofluorescence (IF). Drug sensitivity assay were conducted using popular colorectal cancer cell lines, and patient-derived cell lines (PDCs) established in JFCR under approved IRB. Remaining cancer cells post drug treatment were quantified by IF and imaging analysis. Furthermore, in vivo drug sensitivity was also evaluated.

Results: The CD31 positive luminal structures which shows vascular endothelial tube formation were observed intra multi-layered tissues. The dense microvascular network tended to be formed nearby cancer cells. In comparison with 2D culture model, decreased drug sensitivities were represented in the layered 3D co-cultured model. The evaluated drug sensitivities in 3D model may reflect the response of cancer cells in in vivo.

Conclusion; We developed the layered 3D stromal tissue culture system including blood micro-vessels. Our unique 3D ex vivo model appear to be a valuable tool for drug evaluation, and thus further studies are underway to confirm the usefulness of our model. Testing approved and/or developing compounds with PDCs in the model would potentially enable better prediction their efficacy.

Citation Format: Yuki Takahashi, Kei Tsukamoto, Yuki Shimizu, Ryohei Katayama, Eiji Shinozaki, Satoshi Nagayama, Michiya Matsusaki, Shiro Kitano, Kensei Yamaguchi, Naoya Fujita. A unique ex vivo tumor model: 3D co-cultured system with cancer cells and stromal tissue for drug evaluation [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 322.

Preparation of Extracellular Matrix Paper and Construction of Multi-Layered 3D Tissue Model

Construction of organized three-dimensional (3D) tissue with extracellular matrix (ECM) and multiple types of cells is important for tissue engineering to enable tissue function and enhance cellular function. However, the concentration of ECM and the thickness of the 3D tissue have been limited in previous methods due to a lack of permeability to nutrients and oxygen. Besides, it is difficult to use matured natural ECM as a cell scaffold without chemical modification due to its insolubility. In this article, we focus on multi-layered structure, which is commonly found in living tissue such as skin, blood vessels, and other organs. Here, we describe the preparation of a paper-like scaffold (ECM paper) from micro-fibered natural ECM and the construction of 3D multi-layered tissue composed of cell layers and ECM layers by stacking cell-seeded ECM papers. The thickness and components of the ECM layers are easily controllable by changing the composition of the ECM papers, and the fibrous structure of ECM paper shows high permeability and permits cell migration. Additionally, the ECM microfiber, which is physically defiberized from natural ECM, has a high ECM concentration equal to that of living tissue and high stability under physiological conditions. Therefore, this set of protocols enables construction of multi-layered 3D tissue composed of precisely controlled ECM layers and cell layers that may contribute to the assembly of tissue models. © 2020 by John Wiley & Sons, Inc. Basic Protocol 1: Preparation of extracellular matrix paper Basic Protocol 2: Evaluation of cellular function of cells on extracellular matrix paper Basic Protocol 3: Construction of multi-layered 3D tissue.

A unique ex vivo tumor model: 3D cocultured system with cancer and stromal cells including blood microvessels

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Background: Importance of interaction between cancer and stromal cells has been widely recognized in tumor progression and tolerance against treatment. Although 2D culture and spheroid consisting only cancer cells still remains the preferred platform for most laboratory preclinical studies while these provide only limited information about tumor microenvironment. In order to mimic the patient tumor tissue, ex vivo model which recaptures the tumor microenvironment is required. Methods: Layered 3D stromal tissues comprising microvascular network were produced by culturing fibroblasts and endothelial cells coated with the extra-cellular matrix (ECM) and natural polysaccharide, namely collagen and heparin. The layered 3D stromal tissues and co-cultured tumor were morphologically evaluated by HE stain, immunohistochemistry and immunofluorescence (IF). Their gene expression and secretome profile were characterized by RNA-sequencing and bio-plex suspension array technologies. Furthermore, drug sensitivity assay were conducted using popular colorectal cancer cell lines, and patient-derived cell lines (PDCs) established in the laboratory of JFCR. Remaining cancer cells post drug treatment were quantified by IF and imaging analysis. Results: The 3D stromal tissues including CD31 positive luminal structure were multi-layered (approximately 20 layers), and the tendency that dense microvascular network was formed nearby cancer cells was observed. In comparison with 2D culture or 3D mono-cultured spheroid model, decreased drug sensitivities were represented in the layered 3D co-cultured model. Omics profiles difference among models suggest that our 3D model has some similarity to in vivo tumor. Conclusions: We developed the layered 3D stromal tissue culture system including blood micro-vessels. Drug sensitivity in the co-cultured tumors may reflect the response of cancer cells in in vivo. Our unique 3D ex vivo model appear to be a valuable tool for drug evaluation, and thus testing approved and/or developing compounds with patient-derived cells would enable better prediction their efficacy.

Abstract OT1-12-02: Biomarker study of patients with HER2-negative metastatic breast cancer receiving combination therapy with nivolumab, bevacizumab and paclitaxel as first-line treatment (WJOG9917BTR)

Background: In recent years, anti-PD-1 antibody, an immune checkpoint inhibitor, has been developed for the treatment of various types of cancer, including breast cancer. Synergistic effects of nivolumab, paclitaxel and bevacizumab are expected, based on various preclinical data, when these drugs are administered in combination. A biomarker study is ongoing to evaluate the immune status of patients participating in the NEWBEAT trial, which is a phase II trial of nivolumab + paclitaxel + bevacizumab therapy as first-line treatment for patients with metastatic or recurrent HER2-negative breast cancer. Methods: HER2-negative breast cancer patients from the WJOG9917B (NEWBEAT) trial are enrolled in this biomarker study. To explore new biomarkers for combined treatment of breast cancer with immune-checkpoint inhibitors and anti-vascular endothelial growth factor antibodies, we propose to conduct multicolor immunohistochemistry (IHC) assays for immunomonitoring of the intra-tumor environment, such as the expressions of PD-L1, CD4 and CD8. Blood samples are collected before the start of treatment and at four time-points during the treatment, to determine, using a multicolor flow cytometry panel, the numbers of circulating immunosuppressive cells, such as regulatory T cells, myeloid-derived suppressor cells and tumor-associated macrophages (M2). In the NEWBEAT trial, patients receive nivolumab 240 mg/body on days 1 and 15, paclitaxel 90 mg/m2 on days 1, 8 and 15, and bevacizumab 10 mg/kg on days 1 and 15 every 4 weeks until disease progression. The primary endpoint is the objective response rate, and the key secondary endpoints include progression-free survival, overall survival, and toxicity of the protocol treatment. A total of 51 patients will be enrolled and the enrollment period will be one year. This trial opened to accrual in February 2018. Clinical trial registry number: UMIN000029590

Citation Format: Ozaki Y, Kitano S, Matsumoto K, Takahashi M, Mukohara T, Futamura M, Masuda N, Tsurutani J, Yoshimura K, Minami H, Takano T. Biomarker study of patients with HER2-negative metastatic breast cancer receiving combination therapy with nivolumab, bevacizumab and paclitaxel as first-line treatment (WJOG9917BTR) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT1-12-02.

Liquid biopsy for optimizing the rechallenge of cetuximab in metastatic colorectal cancer: Additional study of E-Rechallenge Trial

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Background: Several previous reports indicated that cetuximab (Cmab) rechallenge may be efficacious in some patients for whom Cmab was previously effective. Liquid biopsy can detect the some emerging mutations for resistance with Cmab. Considering the plasticity and elasticity of sensitive clone, we assumed we could identify the patients with benefit from Cmab rechallenge by liquid biopsy. This current study investigates the predictability of efficacy for Cmab rechallenge by liquid biopsy in the E-Rechallenge Trial. Methods: The E-Rechallenge Trial is a multicenter phase II study in mCRC patients who have become refractory to fluoropyrimidines, L-OHP, CPT-11, Cmab, and bevacizumab, and in whom previous treatment with Cmab was effective in any earlier line (achieving CR, PR, or SD that persisted for ≥ 6 months). The other main eligibility criteria are; RAS wild type, measurable disease, aEFI ≥ 16 weeks between the last dose of Cmab during previous treatment and the start of Cmab rechallenge. Protocol treatment is the combination of weekly Cmab with biweekly CPT-11. Additional research of ctDNA was conducted optionally. Baseline plasma samples were analyzed for KRAS, NRAS, BRAF and EGFR S492R mutations using digital PCR (LBx probe, RIKEN GENESIS). A cut-off of the mutation allele frequency was > 0.1%. Results: Between Dec. 2014 and Oct. 2017, 33 patients were enrolled. The primary endpoint; the rates of PR/SD/PD were PR 15.6%/SD 40.6%/PD 43.8%. Twenty-four of 33 patients participated in the additional research. In the additional cohort, the rates of PR/SD/PD were PR 12.5%/SD 50.0%/PD 37.5%. The mutations were detected at the baseline of Cmab rechallenge as followings; KRAS exon 2 29.2%, exon 3,4 33.3%, BRAF V600E 12.5%, EGFR S492R 12.5%. In wild type of these genes the PR and SD rate increased to 25% and 50%, respectively. Conclusions: Cmab rechallenge showed some activity in the salvage setting, in patients for whom Cmab was previously effective. KRAS, BRAF, and EGFR S492R screening by liquid biopsy may contribute to identify patients with benefit from Cmab rechallenge. The additional data of ctDNA may be provided in the conference. Clinical trial information: UMIN 000016439.

3D collagen microfibers stimulate the functionality of preadipocytes and maintain the phenotype of mature adipocytes for long term cultures

Although adipose tissue is one of the most abundant tissues of the human body, its reconstruction remains a competitive challenge. The conventional in vitro two or three-dimensional (2D or 3D) models of mature adipocytes unfortunately lead to their quick dedifferentiation after one week, and complete differentiation of adipose derived stem cells (ADSC) usually requires more than one month. In this context, we developed biomimetic 3D adipose tissues with high density collagen by mixing type I collagen microfibers with primary mouse mature adipocytes or human ADSC in transwells. These 3D-tissues ensured a better long-term maintained phenotype of unilocular mature adipocytes, compared to 2D, with a viability of 96 ± 2% at day 14 and a good perilipin immunostaining, - the protein necessary for stabilizing the fat vesicles. For comparison, in 2D culture, mature adipocytes released their fat until splitting their single adipose vesicle into several ones with significantly 4 times smaller size. Concerning ADSC, the adipogenic genes expression in 3D-tissues was found at least doubled throughout the differentiation (over 8 times higher for GLUT4 at day 21), along with it, almost 4 times larger fat vesicles were observed (10 ± 4 µm at day 14). Perilipin immunostaining and leptin secretion, the satiety protein, attested the significantly doubled better functionality of ADSC in 3D adipose tissues. These obtained long-term maintained phenotype and fast adipogenesis make this model relevant for either cosmetic/pharmaceutical assays or plastic surgery purposes. STATEMENT OF SIGNIFICANCE: Adipose tissue has important roles in our organism, providing energy from its lipids storage and secreting many vital proteins. However, its reconstruction in a functional in vitro adipose tissue is still a challenge. Mature adipocytes directly extracted from surgery liposuctions quickly lose their lipids after a week in vitro and the use of differentiated adipose stem cells is too time-consuming. We developed a new artificial fat tissue using collagen microfibers. These tissues allowed the maintenance of viable big unilocular mature adipocytes up to two weeks and the faster adipogenic differentiation of adipose stem cells. Moreover, the adipose functionality confirmed by perilipin and leptin assessments makes this model suitable for further applications in cosmetic/pharmaceutical drug assays or for tissue reconstruction.

Catalytic enhancement on Ti–Zr complex oxide particles for electrochemical hydrogenation of oxalic acid to produce an alcoholic compound by controlling electronic states and oxide structures

Ti_0.9Zr_0.1O₂ complex oxide particles exhibit superior catalytic performances for the direct power storage into glycolic acid via electroreduction of oxalic acid due to favorable crystallinity.

Abstract 4580: Changes in the efficacy of anti-EGFR antibody drugs by exosomes derived from colorectal cancer patients

Background: One of the biggest hurdles in cancer treatment is drug resistance. Exosomes are small membrane vesicles of endocytic origin, which contain mRNAs, DNA fragments, and proteins, and are released by many different cell types, including cancer cells. Several studies have shown exosome-mediated drug resistance mechanisms: drug export via the exosome pathway, neutralization of antibody-based drugs and exosome-mediated transfer of miRNAs. Here, we demonstrated the effect of exosomes derived from colorectal cancer (CRC) patients on the efficacy of anti-EGFR agent by in vitro cell-based assay.

Method: Exosomes were purified by ultracentrifugation from culture media of HCT116 cell line and the sera of CRC patients with stage IV pre- and post-treatment with cetuximab (Cmab). As a control, sera from healthy volunteers were used. The number of exosomes and amount of protein were determined by NanoSight and Qubit fluorometer, respectively. The isolated exosomes and 0.01 mg/mL and 0.1 mg/mL of Cmab were added to HT29 and NCI-H508, which stained with PKH dye previously. NCI-H508 is a Cmab super sensitive cell line. After culturing for 3 days, the cells were collected, stained with trypan blue, and the number of the remaining viable cancer cells was calculated with a cell counter. Cmab in the exosome fraction was quantified by ELISA.

Result: HT29 became drug ineffective depending on the number of exosomes produced by Cmab-insensitive HCT-116 harboring KRAS G13D mutation. In addition, exosomes in 9 of 18 cases of colorectal cancer patients changed NCI-H508 into a drug-ineffective state and also correlated with clinical information. In contrast, NCI-H508 was not converted into a drug-ineffective state by exosomes of healthy volunteers and Cmab responder patients. However, on the other hand, quantitative results by ELISA showed that Cmab in sera of some patients remained in the exosome fraction and inhibited the growth of NCI-H508. As a remarkable point, exosomes derived from healthy volunteers significantly promoted the efficacy of Cmab.

Conclusion: In this feasibility study, Cmab resistance in CRC patients may be reproducible by cell-based assay using exosomes. We believe that understanding this mechanism of action will contribute to drug discovery and personalized medicine in the future. Now, we are searching for biomarkers in these exosomes that change the efficacy of Cmab.

Citation Format: Rii Morimura, Kei Tsukamoto, Shinji Irie, Shiro Kitano, Eiji Shinozaki, Kensei Yamaguchi. Changes in the efficacy of anti-EGFR antibody drugs by exosomes derived from colorectal cancer patients [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 4580.

Abstract 5016: A unique ex vivo drug evaluation model: 3D co-cultured system with tumor, stroma and blood microvessels

Background; Two dimensional single-layer culture still remains the preferred platform for most laboratory preclinical studies, although interaction between cancer and stromal cells has been well reported to be important in tumor progression and resistance against therapies. In order to mimic the patient tumor tissues, ex vivo model which recaptures the tumor microenvironment is required.

Methods; Layered 3D stromal tissues were produced by culturing normal human dermal fibroblasts (NHDFs) and human umbilical vein endothelial cells (HUVECs) coated with extra-cellular matrix (ECM) and natural polysaccharide, namely collagen and heparin. The layered 3D stromal tissues and overlaid tumors were morphologically characterized by HE stain, immunohistochemistry (IHC) and immunofluorescence (IF). Furthermore, drug sensitivity assays were conducted using popular colorectal cancer cell lines, and patient-derived cell lines (PDCs) established in the laboratory of Japanese Foundation for Cancer Research. Cancer cell viability was evaluated by fluorescent labeling, enzymatic dissociation and cell counting analysis. IF with cancer specific markers and imaging analyses were also performed.

Results; The 3D stromal tissues including CD31 positive luminal structure were multi-layered (approximately 20 layers), and formation of microvascular network was observed within several days. In comparison with 2D mono-culture or 3D mono/co-cultured spheroid model, decreased drug sensitivities were represented in our 3D co-cultured model. In the simultaneous treatment with cytotoxic anticancer agents and molecular targeted drugs, dose-responses were significantly different between the2D and 3D models.

Conclusion; We developed the layered 3D stromal tissue culture system including blood micro-vessels. Drug evaluation with the co-cultured tumors may reflect the drug sensitivity of cancer cells in vivo. Our unique 3D ex vivo model represents a valuable tool for drug development in a fully human cell and matrix microenvironment, and thus testing patient-derived cells and approved compounds also enable better prediction their efficacy.

Citation Format: Yuki Takahashi, Kei Tsukamoto, Shiro Kitano, Shinji Irie, Michiya Matsusaki, Satoshi Nagayama, Ryohei Katayama, Eiji Shinozaki, Naoya Fujita. A unique ex vivo drug evaluation model: 3D co-cultured system with tumor, stroma and blood microvessels [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 5016.

Abstract 1151: A unique layered 3D stromal tissue model for in vitro evaluation of immunologic agents and immune cell infiltration into cancer microenvironment

Background; The modulation of the immune system is a proven key target for cancer therapy, however, the complex interplay between immune cells and cancer cells in cancer microenvironment remains only partially understood. In addition, the currently available in vitro cancer microenvironment models are not designed to study the immunologic agents and a role of immune cells. Here, we developed a unique layered 3D stromal tissue model comprising an allogeneic immune, stromal and cancer cells.

Method; Human umbilical vein endothelial cells (HUVEC) and normal human dermal fibroblasts (NHDF) were coated with collagen and heparin to construct Extracellular matrix (ECM) nanofilm and cultured to form multi-layers. Lung cancer cells were placed between stromal cells. Furthermore, we added Peripheral Blood Mononuclear Cell (PBMC) and Programmed cell death 1 (PD-1) blockade with Nivolumab and evaluated cytotoxic effects of immune cells on cancer cells and immune cell infiltration by immunohistochemistry.

Result; The co-cultured stromal tissues were multi-layered (approximately 20 layers), and the presence of lung cancer cells between stromal cells was observed. Immunohistochemistry revealed CD8 positive immune cell infiltration into the fibroblast layers. PBMC with Nivolumab treatment significantly decreased the viability of lung cancer cells in this 3D co-culture compared with the results in 2D mono-culture. High level of programmed cell death ligand 1 (PD-L1) expression on lung cancer cell lines correlated with a higher response to PD-1 blockade in vitro as well as clinical trials.

Conclusion; In summary, we present a unique 3D cell culture system based on an allogeneic stromal/cancer/immune cell setting to study immunologic agents and immune cell infiltration in cancer microenvironment. This 3D model has the ability to reflect in vivo conditions closer than 2D model and provide a tool for in vitro immunologic agent testing.

Citation Format: Rii Morimura, Kei Tsukamoto, Shiro Kitano, Eiji Shinozaki. A unique layered 3D stromal tissue model for in vitro evaluation of immunologic agents and immune cell infiltration into cancer microenvironment [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 1151.

In-plane stress development in mesoporous thin films

Ordered mesoporous thin films of TiO2 and CexZr1-xO2 (x = 0, 0.5, 1) were prepared via an evaporation-induced self-assembly (EISA) process and subsequently investigated in terms of the developing intrinsic and residual in-plane stress. These mechanical properties were determined by the curvature method, which is based on the determination of the deflection of light due to concave or convex bending of the films on a substrate. The films were investigated with regard to the intrinsic stress during heat treatment up to 500 °C and to the residual stress at room temperature for several annealing temperatures. Following this strategy, the influence of the decomposition of a block copolymer template on the intrinsic stress as well as the pore collapsing on the residual stress was analyzed. Nanoporous TiO2 thin films were prepared using two different block copolymers (PIB50-b-PEO45 and Pluronic® F127). A comparison between the templated and non-templated TiO2 films showed the lowest intrinsic and residual stress for the ordered mesoporous material prepared with PIB50-b-PEO45 indicating that the distributed polymer and the corresponding mesopores act as relaxing agents for the system. This was verified by mesoporous CexZr1-xO2 (x = 0, 0.5, 1) thin films showing a comparable behavior in terms of the experienced intrinsic stress. This work reveals an increase in the residual in-plane stress during pore collapse, which lays the foundation for further understanding of the stress-related mechanical properties of mesoporous thin films.

Mogamulizumab-induced photosensitivity in patients with mycosis fungoides and other T-cell neoplasms

BACKGROUND

Mogamulizumab (Mog) is a defucosylated, therapeutic monoclonal antibody, targeting CCR4 and was first approved in Japan for the treatment of adult T-cell leukaemia/lymphoma (ATLL), followed by cutaneous T-cell lymphoma and peripheral T-cell lymphoma.

OBJECTIVE

To retrospectively investigate development of photosensitivity in patients with mycosis fungoides and other T-cell neoplasms after treatment with Mog.

METHODS

We treated seven cutaneous lymphoma patients with Mog. Upon combination treatment with narrow-band UVB, we noticed that four patients developed photosensitivity dermatitis following Mog therapy, including two cases of mycosis fungoides, one case of adult T-cell leukaemia/lymphoma and one case of EB virus-associated T-cell lymphoproliferative disorder. Phototest was performed with UVA and UVB, and immunohistochemical staining for CD4, CD8 and Foxp3 was conducted in both photosensitivity and lymphoma lesions.

RESULTS

Phototest revealed that the action spectrum of the photosensitivity was UVB in three cases and both UVB and UVA in one case. Histopathologically, the photosensitive lesions were characterized by a lichenoid tissue reaction with a CD8⁺ T cell-dominant infiltrate, sharing the feature with chronic actinic dermatitis, an autoreactive photodermatosis with a cytotoxic T-cell response. Foxp3⁺ regulatory T cells (Tregs) were decreased in the photosensitivity lesions compared with the lymphoma lesions.

CONCLUSION

Increased incidence of photosensitivity reaction was observed during Mog treatment. Decreased number of Tregs in the lesional skin suggests that this reaction is possibly induced by autoreactive cytotoxic T cells.

Abstract P2-04-13: Difference of immune microenvironment between primary and recurrent tumours in breast cancer patients

Background

Immune checkpoint therapy only benefits a fraction of patients, thus huge efforts have been made to develop predictive biomarkers to identify those patients. Immune biomarkers like PD-L1 expression are extremely dynamic and the timing of evaluation, on primary or metastatic disease, may be critical. We have already shown that tumour-infiltrating lymphocytes (TILs) decrease during metastatic progression in triple-negative (TN) and human epidermal growth factor-2 positive (HER2+) breast cancers (Ogiya R, ASCO 2015), suggesting that mechanisms of immune escape contribute and favour the metastatic progression. In this work we aimed to characterize the modulation and changes of specific immune markers during the metastatic spread comparing paired samples from primary and recurrent breast cancers.

Methods

We retrospectively identified 25 patients with HER2+ (n = 14) and TN (n = 11) early breast cancer diagnosed between 1990 and 2009 at Tokai University Hospital, and who subsequently experienced a first regional or distant recurrence confirmed by tumour biopsy/resection. Haematoxylin and eosin-stained slides of these paired samples were evaluated for stromal TILs. Immunohistochemical staining was performed using primary antibodies against CD4, CD8, Foxp3, PD-L1, PD-L2, and HLA-class I.

Results

The sites of first recurrence was the skin (n = 7), brain (n = 6), lymph node (n = 4), lung (n = 3), bone (n = 2), and one of each of bone marrow, liver and muscle. Immunohistochemical evaluations could not be performed in 5 primary tumours and 2 recurrent tumours because of the small quantity of the specimens. The percentage of CD8+ T cells staining in the primary tumours was significantly higher (median 16%) than that in recurrent tumours (median 10%) (paired t-test, p = 0.008) Similarly, the percentage of CD4+ T cells staining in the primary tumours was significantly higher (median 40%) than that in recurrent tumours (median 25%) (p = 0.026). The percentage of Foxp3+ T cells was low (<10%) and similar in both primary and recurrent tumours (p = 0.16). PD-L1, PD-L2, and HLA class I antibody expression was not statistically different between primary and recurrent tumours, but conversions from positive to negative and vice versa were observed. PD-L1+ staining (≥1%) was 90% and 85% in primary and metastatic tumours, respectively.

Comparison of positivity rate between primary and recurrent tumours for each antibody Primary tumourRecurrent tumourPTotal breast tumours (N)2023 TILs positivity rate, median (%)   CD440%25%.03CD816%10%.01Foxp3<10%<10%.16Expression in tumour cells (N)   PD-L1   Strong85.46Weak1015 Negative23 PD-L2   Strong69.78Weak1011 Negative43 HLA   Strong46.89Weak1415 Negative22 

Conclusions

Tumours at first metastatic recurrence in HER2+ and TN breast cancers have a lower percentage of both CD8+ and CD4+ T cells compared to primary tumours, confirming a potential role of immune escape in tumour progression. Other immune markers, including PD-L1, were not found to change significantly, but negative/positive conversions were observed. This suggest that an evaluation of disease at the time of immunotherapy administration might be more informative. These findings warrant larger confirmation studies.

Citation Format: Ogiya R, Niikura N, Kumaki N, Bianchini G, Kitano S, Iwamoto T, Hayashi N, Yokoyama K, Oshitanai R, Terao M, Morioka T, Tsuda B, Okamura T, Saito Y, Suzuki Y, Tokuda Y. Difference of immune microenvironment between primary and recurrent tumours in breast cancer patients [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-04-13.