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Parenting style is one factor in children's character construction. Preschool students have experienced a change in eating behavior that commonly has the picky eater habit. It is the spectrum of feeding difficulties when children refuse to taste new foods, or only want to eat certain foods. This research aims to identify the correlation between parenting style and pick-eater habits among preschool students in Tri Tunggal Jaya Village. The correlation design method was used to analyze the 55 sample respondents in this village. The measurement tools were questionnaires on parenting styles and picky eater habits (CEBQ). Based on the analysis results, parents in the majority of implemented some parenting styles which were permissive parenting as much 28 (50,9%), democratic parenting as much 25 (45,5%), and authoritarian parenting 2 (3,6%). Meanwhile, the picky eaters in the majority showed a rate of 25 (45,5%) and non-picky eaters were 30 (54,5%). According to the gamma testing, it showed that the p-value was 0,000. Thus, it can be concluded that there is a correlation between parenting style in picky eating habits among preschool students in Tri Tunggal Jaya Village, located in the sub-district Penawartama Tulang Bawang regency. Suggestion: for the parents, it will be better to implement a good parenting style for the children in managing childhood eating patterns. Abstrak: Pola asuh adalah salah satu faktor dalam pembentukan karakter anak. Anak usia prasekolah mengalami proses perubahan pola makan dimana anak pada usia ini umumnya mengalami peri laku atau kebiasaan Picky eater yang termasuk kedalam spektrum kesulitan makan (feeding difficulties) dimana anak menolak untuk mencoba makanan baru, atau hanya mau makan makanan tertentu. Tujuan penelitian ini adalah untuk mengidentifikasi hubungan pola asuh Orangtua dengan perilaku Picky eater pada anak usia prasekolah di Desa Tri tunggal jaya. Metode penelitian ini menggunakan desain korelasi dengan jumlah sampel 55 responden di Desa Tri Tunggal Jaya. Alat ukur yang digunakan dalam penelitian ini adalah kuesioner pola asuh dan kuesioner perilaku Picky eater (CEBQ). Dari hasil penelitian didapakan bahwa mayoritas orangtua menerapakan pola asuh permisif yaitu 28 (50,9%), pola asuh demokratis 25 (45,5%), dan pola asuh otoriter 2 (3,6%). Sedangkan mayoritas picky eater 25 (45,5%) dan tidak picky eater 30 (54,5%). Berdasarkan uji gamma didapatkan nilai p value sebesar 0,000 maka dapat di simpulkan ada hubungan antara pola asuh Orangtua kebiasaan memilih-milih makan (Picky eater) pada anak usia prasekolah di Desa Tri Tunggal Jaya Kecamatan Penawartama Kabupaten Tulang Bawang. Saran: Diharapkan kepada orang tua untuk menerapkan pola asuh yang baik dan benar kepada anaknya untuk lebih tepat dalam mengatur pola makan anak.

Supplementary Materials and Methods. Supplementary Table S1. QC of Affymetrix U133_Plus_2.0 Data. Supplementary Table S2. Summary of the Objective Response Measure (ORM) scoring methodology. Supplementary Table S3. Correlation of xenograft with parent U133_Plus_2.0 expression. Supplementary Table S4. Probe sets where parent expression is always greater than xenograft. Supplementary Table S5. Probe sets where xenograft expression is always greater than parent. Supplementary Table S6. Complete summary of in vivo AZD1480 single agent responses for individual mice. Supplementary Table S7. In vitro Combination Indices (CIs) for AZD1480 and selumetinib. Supplementary Table S8. In vivo responses of JAK-mutated ALL xenografts to AZD1480/selumetinib combination treatment. Supplementary Table S9. Complete summary of in vivo AZD1480 single agent and AZD1480/selumetinib combination responses for individual mice. Supplementary Figure S1. Chemical structures of (A) AZD1480 and (B) selumetinib. Supplementary Figure S2. Relationship between high CRLF2 expression and engraftment potential of the P9906 cohort. Supplementary Figure S3. Probe set expression by range. Supplementary Figure S4. Heatmap of microarray gene expression data corresponding to the qRT-PCR data shown in Figure 1. Supplementary Figure S5. In vitro cytotoxicity of AZD1480 against ALL xenograft cells. Supplementary Figure S6. In vivo efficacy of single agent AZD1480 against ALL xenografts. Supplementary Figure S7. Time of drug exposure affects synergistic interactions of AZD1480 and selumetinib against JAK-mutated ALL xenografts. Supplementary Figure S8. The extent of inhibition of the JAK/STAT and MAPK signaling pathways depends on the length of exposure to AZD1480/selumetinib.

Supplementary Figures S6-S9. Correlations between BCL2 family gene expression and in vivo ABT-263 sensitivity in the MLL-ALL xenograft panel; S7. Correlations between BCL2 family gene expression and in vivo ABT-263 sensitivity in the BCP-ALL xenograft panel; S8. Correlations between BCL2 family gene expression and in vivo ABT-263 sensitivity in the T-ALL xenograft panel; S9. Representative immunoblot of MCL1 protein expression in ALL xenografts.

This paper reports the performance of a graphite and silica nanoparticles-based delivery system forT. harzianumin controlling the in vitro growth ofR. solaniand damping-off disease on tomato plants. The in vitro and in vivo experiments were arranged in the randomized complete block design. The in vitro treatment was a dual culture ofR. solaniandT. harzianumin the various components of formulation on PDA, i.e.,T. harzianum+ 5 wt.% graphite,T. harzianum+ 1wt.% silica NPs.,T. harzianum+ 5 wt.% graphite + 1 wt.% silica nanoparticles,T. harzianum, 5 wt.% graphite, 1 wt.% silica nanoparticles, fungicide (mancozeb), and a control. The in vivo treatment included the application ofT. harzianumin the same compositions as the in vitro treatment, except that there were two controls i.e., inoculated and noninoculated tomato plants withR. solani.T. harzianumby soaking tomato seeds in the formulation suspensions before planting. The results showed that all formulation compositions were able to inhibit the in vitro growth ofR. solani. The inhibitions of the colony growth ofR. solanicaused by formulated and non-formulatedT. harzianumwere the same. This proved that graphite and silica NPs did not resist to the ability ofT. harzianumin controllingR. solani, indicated that the formulation was promising to develop. However, the inhibition of damping-off disease incidence on tomato plants caused by formulatedT. harzianumwas the same as the non-formulated one only on day 7 after treatments. On days 14, 21, and 28, the inhibitions were lower than the non-formulated ones. It was suggested to reapply the formulation ofT. harzianumin the soil at planting and several days after.

Introduction: GARP (Glycoprotein-A repetitions predominant) is a cell surface receptor which is coded by Lrrc32 (Leucine rich repeat containing protein 32) and involved in the activation of TGF-beta. The expression of GARP has been widely found in various cells including Treg, activated B cells, mesenchymal stromal cells and many types of cancer cells. In the tumor microenvironment (TME), GARP from Treg promotes the growth of tumor via secretion of immune suppressive TGF-beta. Result: We established GARP humanized mouse model (hGARP) on C57BL/6 background in which the signal peptide and extracellular domain of mouse GARP (mGARP) was replaced by human GARP (hGARP). Similar expression level of hGARP on Treg cells in splenocytes from C57BL/6-hGARP mice was observed compared with mGARP in wildtype mice. After treating with anti-hGARP antibody, tumor growth was inhibited in the cohort engrafted with MC38 colorectal cancer cell line. Flow cytometry analysis of the tumor infiltrating lymphocytes revealed an abundant accumulation of hGARP on the Treg cells suggesting that blocking of hGARP in Treg cells contributed to the therapeutic efficiency. In addition, hGARP expression was also found on platelet cells from C57BL/6-hGARP mice, which is similar to human. After treating with anti-hGARP, we also found a significant reduction of platelet cells in C57BL/6-hGARP mice. In vivo assay suggested that the reduction of platelet cells from C57BL/6-hGARP mice correlated well with the binding of anti-hGARP. Conclusion: C57BL/6-hGARP is a well-established mouse model for the pre-clinical evaluation of both therapeutic effect and toxicity of anti-hGARP therapy. Citation Format: Xing Liu, Meirong Wu, Huiyi Wang, Weiwei Yu, Jianming Xu, Hongyan Sun, Cunxiang Ju, Hongyu Wang, Santi Suryani Chen, Zhiying Li, Mark Wade Moore, Jing Zhao, Xiang Gao. Humanized mice for preclinical efficacy evaluation of drugs targeting GARP. [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 5198.

Hematological malignancies, including leukemia, lymphoma and multiple myeloma, account for about 7% of all newly diagnosed cancers. Allogeneic hematopoietic stem cell transplantation (HSCT) is a traditional treatment for hematologic malignancies. Currently, CAR-T cell therapy has made a major breakthrough in the treatment of hematologic malignancies. However, the occurrence of acute Graft-versus-Host Disease (GvHD) represents a major obstacle for HSCT and limits the application of CAR-T cell therapy. GemPharmatech established and characterized two murine models for anti-GvHD drug evaluation. In the first model, bone marrow from C57BL/6 donor mice was transplanted into a sublethally-irradiated BALB/c recipient mouse. In this model, T cell infiltration, tissue damage, and systemic inflammation were observed, similar to the clinical observations of patients receiving allogeneic HSCT. Efficacy evaluation of anti-GVHD drugs have been carried out based on this model. Our results showed that treatment with the anti-GVHD drug Ibrutinib, the survival rate and the lifespan of the mice was significantly prolonged, and the GvHD score was reduced by about 70% compared with the placebo group. In the second model, human Peripheral Blood Mononuclear cells (PBMCs) were transplanted into irradiated severe immunodeficient NCG mice. The cohort was irradiated to accelerate GvHD occurrence. The reconstructed human T cells will recognize and attack mouse tissues to cause GvHD. Our results showed that hCD45+ cells infiltrated into heart, liver, and spleen of huPBMC-NCG mice. This model has also been successfully used for anti-GvHD efficacy evaluation. Upon treatment with an anti-GVHD drug, the lifespan of huPBMC-NCG mice was significantly extended and weight loss was alleviated. Overall, the above-mentioned GvHD models show great potential for preclinical evaluation of anti-GvHD drug development in allogeneic HSCT. Citation Format: Meirong Wu, Shiru Zhang, Fang Zhu, Hongyan Sun, Jianming Xu, Cunxiang Ju, Hongyu Wang, Santi Suryani Chen, Zhiying Li, Mark Wade Moore, Jing Zhao, Xiang Gao. A mouse model for GvHD: an excellent tool for evaluating the efficacy of anti-GvHD drugs and testing mechanisms of immunoregulation. [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 4472.

Immune checkpoint molecule B7-H3, also known as CD276, is a member of the B7-CD28 family of immunomodulatory proteins. It is a type I membrane protein with sequence similarities to the extracellular domain of programmed death-ligand 1 (PD-L1). B7-H3 is highly expressed in most human cancers, but has limited distribution in normal tissues, remaining elusive of its receptor. Due to its promising safety as a dominant tumor target, various strategies have been developed to modulate the effect of B7-H3 via monoclonal antibodies, bispecific antibodies, ADC, or CAR-T. To study the effect of these therapies in an immunocompetent mouse model, we established a double humanized B7-H3 and PD-L1 mouse model on BALB/c background (BALB/c-hB7-H3/hPD-L1). In this model, the extracellular domain of murine fragments was replaced by the human counterparts while the trans-membrane and cytoplasmic domain were kept intact. When engrafted with CT26 colon cancer cells, which stably overexpress human B7-H3 and PD-L1 while endogenous murine counterparts were knocked out, the tumor growth was inhibited certain degree by anti-B7-H3 antibody (8H9 Biosimilar, 20mpk, TGI=18.56%) treatment while inhibited significantly after the monotherapy of anti-PD-L1 (Tecentriq, 3 mpk, TGI=55.89%, p Based on the above, the B7-H3 and PD-L1 double humanized mouse model is suitable for the pre-clinical evaluation of mono or combined immune checkpoint blockade with anti-human B7-H3 and PD-L1 therapy. Citation Format: Shiying Guo, Lingyu Song, Xin Qin, Jianming Xu, Hongyan Sun, Cunxiang Ju, Hongyu Wang, Santi Suryani Chen, Zhiying Li, Mark Wade Moore, Jing Zhao, Xiang Gao. B7-H3 & PD-L1 double-humanized BALB/c mouse: a novel animal model for preclinical studies of human B7-H3 antibodies or bispecific antibodies. [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 5199.

Severe immunodeficient mice engrafted with human hematopoietic stem cells (HSC) have been extensively used in immuno-oncology related studies to evaluate the efficacy of cancer therapies. However, because of species differences, murine cytokines provide limited support to human immune cells, thus immunodeficient mice have limited engraftment of human immune cells. Increasing evidence has shown that myeloid cells, especially macrophages and dendritic cells, are critical for the induction of anti-tumor immunity. We developed a mouse model, NCG-M, that can support human T, B, NK and myeloid cells such that in vivo evaluation of agents that require the interplay between these immune cells can be examined. This model was genetically engineered on the severe immunodeficient strain NCG and can produce human granulocyte/macrophage colony stimulating factor 2 (GM-CSF, also known as CSF2), interleukin-3 (IL-3) and stem cell factor (SCF, also known as KITLG). Upon human CD34+ HSC cell engraftment, increased myeloid lineage cells, such as granulocytes, monocytes, neutrophils, macrophages, and dendritic cells, were observed in the NCG-M cohort compared to NCG mice. The NCG-M mouse also supports the development of human T cells, and preliminary data showed increased B and NK cells. The NCG-M is an appropriate mouse model for studying the efficacy of therapeutic agents that require human T cells and myeloid cells. Citation Format: Huiyi Wang, Jialu Fan, Shiying Guo, Mingkun Zhang, Shuai Li, Santi Suryani Chen, Zhiying Li, Mark Wade Moore, Jing Zhao, Xiang Gao, Cunxiang Ju. NCG-M humanized mice: an excellent model for human immune reconstitution of myeloid lineages. [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 5202.

Antibody-drug conjugates (ADCs) are effective anti-tumor therapies with high specificity, with little toxicity and side effects. Xenograft tumor models based on immunodeficient mice have been used for evaluating the human anti-tumor efficacy of ADCs. However, the antibody-mediated immune response of ADCs is not well evaluated in immunodeficient mice. To this end, we have developed BALB/c-hPD1 humanized mouse model to evaluate the efficacy of ADCs in combination with immunotherapy. Trastuzumab deruxtecan (T-DXd, DS-8201a) is a HER2-targeting ADC. In vitro efficacy studies showed that T-DXd effectively bound to the HER2-positive cell line SK-BR-3, resulting in strong endocytosis and induction of apoptosis. It has also been shown to kill HER2-negative MDA-MB-468 cells through a bystander effect both in vitro and in vivo. In vivo efficacy studies have demonstrated that ADCs can effectively inhibit human tumor cell growth in immunodeficient mice. In addition to human tumor cell lines, the efficacy of ADCs was also studied in BALB/c-hPD1mice engrafted with murine colon cancer cells model, and the results showed that T-DXd and Keytruda could significantly inhibit CT26-hHER2 tumor growth, with the tumor growth inhibition rates being 57% and 66%, respectively, Tumor growth inhibition rate of the combined treatment group was about 91%, which was superior compared to the efficacy of single drug treatment. The evaluation of Fc segment-mediated effect (such as ADCC, CDC and ADCP) of ADCs antibodies was carried out in humanized immune system mouse models, such as NCG-hIL15 and NCG-hSGM3. In summary, we have established a drug evaluation platform using various humanized mouse models to study the synergistic anti-tumor effects of ADCs combined with immune checkpoint blockade antibodies. Citation Format: Fang Zhu, Hongyan Sun, Qian Lu, Yuan Fang, Jianming Xu, Cunxiang Ju, Hongyu Wang, Santi Suryani Chen, Zhiying Li, Mark Wade Moore, Jing Zhao, Xiang Gao. Efficacy evaluation by novel humanized mouse models for preclinical study of ADCs combined with immunotherapy [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 3242.

Human immune cell reconstitution (PBMC or CD34+ hematopoietic stem cell; HSC) is commonly performed in immunodeficient mouse strains such as NCG, NSG, or NOG. The use of PBMC is preferred for multiple reasons, including faster engraftment, lower cost, and the presence of mature immune cell populations. Although there are donor-to-donor variations in GvHD occurrence, and specific donors can be screened, the symptoms of GvHD typically occur within 4 weeks. GvHD significantly limits the study window required to evaluate the efficacy of therapeutic agents, such as cancer immunotherapies. GvHD is an immune reaction triggered mainly by donor T cells identifying the mouse MHC class I and class II as foreign and attacking the host cells and organs. Deletion of β2m (NCG- β2m-KO) reduces the occurrence of GvHD; however, β2m is not only in the MHC class I subunit but also in the FcRn subunit, of which deletion shortens the half-life of IgG, making it unsuitable for IgG antibody agent evaluation. In addition, the deletion of MHC class I or class II alone results in an imbalanced CD4/CD8 ratio. To solve these problems, we developed the NCG-MHC-dKO mouse model by knocking out the H2K1, H2D1, and H2Ab1 genes. Compared with the existing NCG- β2m-KO or other β2m null mouse models, the NCG-MHC-dKO significantly prolonged survival, reduced GvHD occurrence, and did not affect the CD4/CD8 ratio when reconstituted with PBMC. Furthermore, treatment with anti-PD-L1 antibodies significantly inhibited MDA-MB-231 tumor cell growth in PBMC-reconstituted NCG-MHC-dKO mice, similar to NCG mice. Based on our preliminary data, the NCG-MHC-dKO mouse is a promising model for antibody and cell therapy agent evaluation, assessing treatment-related cytokine release syndrome, and evaluating long-term toxicities of cell therapies. Citation Format: Huiyi Wang, Jun Xing, Jialu Fan, Huanhuan Hou, Santi Suryani Chen, Zhiying Li, Mark Wade Moore, Jing Zhao, Xiang Gao, Cunxiang Ju. NCG-MHC-dKO mice: an excellent model for PBMC reconstitution and pharmacodynamic evaluation in the absence of GvHD. [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 5192.

In May 2021, the FDA approved sotorasib (Lumakras™) as the first treatment for adult patients with non-small cell lung cancer (NSCLC) harboring the KRASG12C genetic mutation. To study the relationship between the mutational activation of KRAS and tumorigenesis, and promote the development of KRAS-G12C inhibitors, we established the B6-Loxp-Stop-Loxp Kras G12C (B6-KrasLSL-G12C) strain. Upon induction of Cre recombinase, floxed Stop sequences will be deleted in the mouse genome, and the oncogenic KRAS-G12C protein will be expressed at endogenous levels allowing for control of the timing and location of tumor initiation. The C57BL/6-KrasLSL-G12C mice were crossed with the Lyz2-cre mice to develop a spontaneous lung cancer model. KRAS G12C mutant could be detected in type II alveolar epithelial cells (ATII). Furthermore, these mice develop lung cancer at 8-10 weeks of age. In addition, when B6-KrasLSL-G12C mice were crossed with the B6-P53LSL-R172H and Ptf1/p48-Cre mice, the offspring developed pancreatic cancer after 10-12 weeks of tamoxifen treatment. In conclusion, B6-KrasLSL-G12C mice can be used to study the occurrence and development of pancreatic and lung cancer, as well as the potential applications of cancer therapies. Citation Format: Xiaoliu Yang, Yunlong Jiang, Xue Wu, Mingkun Zhang, Jing Zhao, Santi Suryani Chen, Zhiying Li, Erica Trujillo, Mark Wade Moore, Xiang Gao, Cunxiang Ju. B6-KrasLSL-G12C mouse model for assessing the occurrence and development of lung and pancreatic cancer 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 5205.

Tumor necrosis factor (TNF) receptor 2 (TNFR2) is mainly expressed on the surface of regulatory T cells (Tregs) and CD8+ T cells, which can stimulate the proliferation of these cells through NF-kB activation. TNFR2 is also highly expressed on the surface of various human tumors, such as colorectal cancer and lung cancer. Therefore, a TNFR2 antagonist blocking the binding of TNFR2 to its ligand that targets TNFR2+ tumor-infiltrating Tregs can directly enhance the killing ability of effector T cells (Teff) against TNFR2-expressing tumors. Many pharmaceutical and biotech companies have lined up TNFR2-targeting drugs, and most TNFR2 antibodies related research is in the early preclinical/clinical stage. We established a humanized TNFR2 (hTNFR2) genetically engineered mouse model on the BALB/c background, in which the extracellular domain of the mouse TNFR2 was replaced with its human counterpart, and the murine transmembrane and cytoplasmic domain kept intact. The hTNFR2 chimeric protein is mainly expressed on Teff and Treg cells in BALB/c-hTNFR2 and BALB/c-hPD1/hPDL1/hTNFR2 mice, which is similar to mouse TNFR2 protein expression profiles in wild-type mice. Our data showed that anti-TNFR2 antibodies could significantly inhibit tumor growth in BALB/c-hTNFR2 mice bearing CT26 tumor cells or BALB/c-hTNFR2 mice bearing CT26-hTNFR2 tumors. Furthermore, within the tumor-infiltrating lymphocytes, there was a reduction in Tregs cells and an increase in cytotoxic CD8 T cells, which accurately mimics the mechanism of action of anti-TNFR2 antibodies. In conclusion, BALB/c-hTNFR2 and BALB/c-hPD1/hPDL1/hTNFR2 mice are ideal models for studying the efficacy and pharmacodynamics of anti-TNFR2 antibodies as a single agent or in combination with anti-PD-1/PD-L1 therapies. Citation Format: Huiyi Wang, Ying Li, Mingkun Zhang, Xu Su, Santi Suryani Chen, Zhiying Li, Mark Wade Moore, Jing Zhao, Xiang Gao, Cunxiang Ju. TNFR2 humanized mice: an ideal model for studying anti-TNFR2 antibodies. [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 5201.

Introduction: IL-15 is a four α-helix bundle cytokine which is produced by dendritic cells, monocytes, and epithelial cells. IL-15 is necessary for the development, survival, and activation of natural killer (NK) cells. NK cells are unable to persist in immunodeficient NCG mice reconsituted with human NK cells, but after knocking in human IL-15 (hIL-15), NCG-hIL15 mice can support the reconstitution and survival of human NK cells. Results: Compared with NCG mice, the level of hIL-15 was significantly increased in NCG-hIL15 mice. After transplanting human PBMC (huPBMC) or NK (huNK) cells into NCG-hIL15 mice, the peripheral blood level of NK cells in huNK-NCG-hIL15 mice was much higher than in huPBMC-NCG-hIL15 mice. The expression of perforin in peripheral blood of huNK-NCG-hIL15 mice was significantly higher than that in huPBMC-NCG-hIL15 mice. Considering the obvious ADCC of rituximab acting on Raji cells in vitro, we evaluated the efficacy of rituximab in huNK-NCG-hIL15 mice subcutaneously engrafted with Raji cells. Rituximab significantly inhibited the tumor growth in huNK-NCG-hIL15 mice. Conclusion: NCG-hIL15 is a great mouse model to evaluate the anti-tumor efficacy of drugs targeting human NK cells without the interference of T cells. Citation Format: Xing Liu, Meirong Wu, Huiyi Wang, Weiwei Yu, Jianming Xu, Hongyan Sun, Cunxiang Ju, Hongyu Wang, Santi Suryani Chen, Zhiying Li, Mark Wade Moore, Jing Zhao, Xiang Gao. NCG-hIL15 humanized mice: an ideal model for human immune reconstitution of NK cells. [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 3970.

Hukum dan moral adalah satu kesatuan yang tidak dapat dipisahkan. Disatu sisi hukum yang ideal, maka hukum berfungsi sebagai moral, dan moral berfungsi sebagai hukum. Namun ketika melihat kasus-kasus hukum yang terjadi hari ini, menunjukan bahwa kasus tersebut bertentangan juga menurut moral, semisal korupsi, ketidakpatuhan hukum, pembunuhan dan lain sebagainya, dimana hal ini disebabkan oleh tidak terintegrasinya kesadaran moral antara individu satu dan invidu lainnya. Sehingga ketika hal ini terus dilanggengkan maka penegakan hukum bergaya moral itu akan sulit ditegakan. Tulisan ini bertujuan untuk : 1) menguak serta menggali tentang pentingnya membangun integritas moral bagi masyarakat (penegak hukum) yang akan menegakan hukum di Indonesia; 2) menguak serta menggali tentang penegakan hukum yang baik (ideal) menurut gaya moral di Indonesia. Hasil penelitian menunjukkan bahwa : 1) dalam rangka membangun integritas moral bagi masyarakat (penegak hukum) yang akan menegakan hukum di Indonesia, maka perlu membangun dan menciptakan kesadaran hukum bagi masyarakat (penegak hukum), dimana ini akan berimplikasi pada dinamika sosial; 2) penegakan hukum yang baik (ideal) menurut gaya moral di Indonesia dapat tumbuh dengan sendirinya, yakni dengan mengikuti tatanan sosial yang hidup dan berkembang selaras dengan zaman yang sedang dilaluinya, artinya penegakan hukum dilakukan dengan melihat perkembangan dinamika dalam masyarakat. Adapun metode penelitian yang digunakan dalam penelitian ini adalah dengan menggunakan pendekatan historis, komparatif dan konseptual guna menguak serta menggali tentang idealitas penegakan hukum yang baik (ideal) menurut gaya moral di indonesia.

CD47 is widely expressed on the surface of cells. CD47 interacts with inhibitory receptor signaling protein alpha (SIRPα) to mediate a series of activities such as apoptosis, proliferation, and immune response. Tumor cells can escape the immune surveillance of macrophages through the CD47-SIRPa signaling pathway. Blocking CD47-SIRPα interactions has been shown to promote the destruction of cancer cells by phagocytes. Furthermore, there is growing evidence that targeting of the CD47-SIRPα axis may also promote antigen-presenting cell function. These identify the CD47-SIRPα axis as a promising innate immune checkpoint in cancer. We have generated humanized SIRPα and double humanized CD47/SIRPα mice model for drug efficacy and toxicity evaluation. The humanized mice with human extracellular domain and mouse cytoplasmic fragment of target protein showed similar immune cell population compared with wild type mice. The anti-CD47 antibody, Magrolimab (5F9) analog, displayed anti-tumor effect when administrated to humanized SIRPα mice bearing MC38-hCD47 (MC38 cells engineered to express human CD47) tumor cells. The tumor regression was also observed when treating humanized CD47/SIRPα mice bearing MC38-hCD47 with tested anti-CD47 antibody. Dual checkpoint blockade of CD47 and PD-L1 or PD1 have been reported as a synergistic therapy that activates both innate and adaptive immune response against tumors.We also generated humanized PD1/SIRPα and PD1/PDL1/SIRPα/CD47 mice model for efficacy and toxicity evaluation of drugs targeting for CD47/SIRPα-PD1/PD-L1 axes. Treatment with anti-CD47, anti-SIRPα and anti-PD-L1 alone showed tumor regression efficacy, and combination of anti-PD-L1 and anti-SIRPα or anti-CD47 showed improved anti-tumor effect compared with alone treatment. Those data suggested the humanized syngeneic mice model are useful for the efficacy evaluation of drugs targeting of axes.However, the administration of anti-CD47 blocking antibodies may cause haematotoxicity, including anaaemia and thrombocytopenia, because of the ubiquitous expression of CD47.In vitro Erythrocyte binding activity analysis showed that red blood cells(RBC) collected from humanized CD47/SIRPα mice could bind with Magrolimab analog, while another anti-CD47 antibody has low affinity with RBC. Furthermore, treatment with Magrolimab analog in CD47/SIRPα humanized mice caused haemagglutination and Hemolysis of human RBCs, which were not observed when treating with tested anti-CD47 antibody. Thus, the humanized CD47 and double humanized CD47/SIRPα mice are also suitable for CD47 antibody toxicity evaluation. In conclusion, humanized CD47/SIRPα and quadruple humanized PD1/PDL1/SIRPα/CD47 mice model provide a validated preclinical mouse model to interrogate new therapeutic agents targeting SIRPα-PD1 axes in immune oncology therapy. Citation Format: Juan Liang, Cunxiang Ju, Song Li, Weiwei Yu, Hongyan Sun, Santi Suryani Chen, Jing Zhao, Xiang Gao, Mark Moore. Humanized mice model for efficacy and toxicity evaluation of drugs targeting CD47-SIRPα-PD1-PD-L1 axes [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 607.

Lymphocyte activation gene 3 (LAG-3) is a member of the immunoglobulin superfamily which shares homolog with CD4 and binds to MHC II with higher affinity. It is expressed on activated T cells, regulatory T cells (Tregs), natural killer cells and plasmacytoid dendritic cells, and inhibits their activation. Blocking LAG-3 activity is expected to provide therapeutic benefits in the treatment of cancer, especially when combined with PD-1 blockade. Due to the low homology between human and mouse LAG-3 and PD-1 and in order to enable increased translatability of preclinical in-vivo efficacy evaluation of immune checkpoint antibodies, we generated double humanized mice by replacing the extracellular domain of mouse LAG-3 and PD-1 with the corresponding human sequences. Homozygous double humanized mice express chimeric LAG-3 and PD-1 at comparable levels to mouse LAG-3 and PD-1 respectively in wildtype mice. When treated with human LAG-3 antibody (anti-LAG-3) or human PD-1 antibody (anti-PD-1), CT26 tumor growth was inhibited in a dose-dependent manner, proving that both humanized proteins are functional. However, not all tumor types respond to anti-LAG-3 or anti-PD-1 the same. To identify the suitable tumor models for preclinical efficacy evaluation of anti-LAG-3 and anti-PD-1 combo therapy, we engrafted several syngeneic tumor models onto our mice. The growth of subcutaneously engrafted MC38 colon tumor was mildly inhibited by anti-PD-1, but strongly inhibited in the presence of anti-LAG-3. Similarly, B16F10 melanoma tumor showed modest growth inhibition when treated with anti-PD-1 or anti-LAG-3 separately, while combination therapy significantly repressed tumor growth. However, neither monotherapies of anti-LAG-3 and anti-PD-1 nor combination treatment effectively inhibited tumorigenesis of LLC1 derived lung cancer, indicating that this tumor is likely insensitive to PD-1 and LAG-3 blockade. Collectively, these data indicate that double humanized PD-1 and LAG-3 mice are a powerful tool to evaluate the therapeutic efficacies of anti-hPD-1 and anti-hLAG-3 treatment in different types of tumor in vivo. Citation Format: Feifei Duan, Xiaoliu Yang, Cunxiang Ju, Jing Zhao, Xiang Gao, Santi Suryani Chen. Humanized PD-1/LAG-3 mice for preclinical evaluation of combination therapy [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 590.

Aberrant ERG (v-ets avian erythroblastosis virus E26 oncogene homolog) expression drives leukemic transformation in mice and high expression is associated with poor patient outcomes in acute myeloid leukemia (AML) and T-acute lymphoblastic leukemia (T-ALL). Protein phosphorylation regulates the activity of many ETS factors but little is known about ERG in leukemic cells. To characterize ERG phosphorylation in leukemic cells, we applied liquid chromatography coupled tandem mass spectrometry and identified five phosphorylated serines on endogenous ERG in T-ALL and AML cells. S283 was distinct as it was abundantly phosphorylated in leukemic cells but not in healthy hematopoietic stem and progenitor cells (HSPCs). Overexpression of a phosphoactive mutant (S283D) increased expansion and clonogenicity of primary HSPCs over and above wild-type ERG. Using a custom antibody, we screened a panel of primary leukemic xenografts and showed that ERG S283 phosphorylation was mediated by mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling and in turn regulated expression of components of this pathway. S283 phosphorylation facilitates ERG enrichment and transactivation at the ERG +85 HSPC enhancer that is active in AML and T-ALL with poor prognosis. Taken together, we have identified a specific post-translational modification in leukemic cells that promotes progenitor proliferation and is a potential target to modulate ERG-driven transcriptional programs in leukemia.

Genome-wide studies have identified a high-risk subgroup of pediatric acute lymphoblastic leukemia (ALL) harboring mutations in the Janus kinases (JAK). The purpose of this study was to assess the preclinical efficacy of the JAK1/2 inhibitor AZD1480, both as a single agent and in combination with the MEK inhibitor selumetinib, against JAK-mutated patient-derived xenografts. Patient-derived xenografts were established in immunodeficient mice from bone marrow or peripheral blood biopsy specimens, and their gene expression profiles compared with the original patient biopsies by microarray analysis. JAK/STAT and MAPK signaling pathways, and the inhibitory effects of targeted drugs, were interrogated by immunoblotting of phosphoproteins. The antileukemic effects of AZD1480 and selumetinib, alone and in combination, were tested against JAK-mutated ALL xenografts both in vitro and in vivo. Xenografts accurately represented the primary disease as determined by gene expression profiling. Cellular phosphoprotein analysis demonstrated that JAK-mutated xenografts exhibited heightened activation status of JAK/STAT and MAPK signaling pathways compared with typical B-cell precursor ALL xenografts, which were inhibited by AZD1480 exposure. However, AZD1480 exhibited modest single-agent in vivo efficacy against JAK-mutated xenografts. Combining AZD1480 with selumetinib resulted in profound synergistic in vitro cell killing, although these results were not translated in vivo despite evidence of target inhibition. Despite validation of target inhibition and the demonstration of profound in vitro synergy between AZD1480 and selumetinib, it is likely that prolonged target inhibition is required to achieve in vivo therapeutic enhancement between JAK and MEK inhibitors in the treatment of JAK-mutated ALL. Mol Cancer Ther; 14(2); 364–74. ©2014 AACR.

The clinical success of the BCL-2-selective BH3-mimetic venetoclax in patients with poor prognosis chronic lymphocytic leukemia (CLL) highlights the potential of targeting the BCL-2-regulated apoptotic pathway in previously untreatable lymphoid malignancies. By selectively inhibiting BCL-2, venetoclax circumvents the dose-limiting, BCL-XL-mediated thrombocytopenia of its less selective predecessor navitoclax, while enhancing efficacy in CLL. We have previously reported the potent sensitivity of many high-risk childhood acute lymphoblastic leukemia (ALL) xenografts to navitoclax. Given the superior tolerability of venetoclax, here we have investigated its efficacy in childhood ALL. We demonstrate that in contrast to the clear dependence of CLL on BCL-2 alone, effective antileukemic activity in the majority of ALL xenografts requires concurrent inhibition of both BCL-2 and BCL-XL We identify BCL-XL expression as a key predictor of poor response to venetoclax and demonstrate that concurrent inhibition of both BCL-2 and BCL-XL results in synergistic killing in the majority of ALL xenografts. A notable exception is mixed lineage leukemia-rearranged infant ALL, where venetoclax largely recapitulates the activity of navitoclax, identifying this subgroup of patients as potential candidates for clinical trials of venetoclax in childhood ALL. Conversely, our findings provide a clear basis for progressing navitoclax into trials ahead of venetoclax in other subgroups.

B-cell development is characterized by the progressive maturation of hematopoietic stem cells through several stages to ultimately give rise to the mature B-cell pool that has been selected for reactivity against non-self antigens. Thus, the mature pool of naive B cells is capable of elicting high-affinity responses following natural infection with pathogens or vaccination and provides the host with protective long-lived humoral immunity. However, perturbations during the processes of B-cell development and differentiation can give rise to a diverse array of immunological diseases including autoimmunity, immunodeficiency and malignancy. While we have a very rich understanding of the processes underlying B-cell development in mice, our knowledge of the corresponding events occurring in human B cells is substantially less robust. Here, we overview the latest findings relating to human B cells in health and disease with a particular emphasis on the transitional stage of B-cell development.

The transitional stage of B-cell development represents an important step where autoreactive cells are deleted, allowing the generation of a mature functional B-cell repertoire. In mice, 3 subsets of transitional B cells have been identified. In contrast, most studies of human transitional B cells have focused on a single subset defined as CD24hiCD38hi B cells. Here, we have identified 2 subsets of human transitional B cells based on the differential expression of CD21. CD21hi transitional cells displayed higher expression of CD23, CD44, and IgD, and exhibited greater proliferation and Ig secretion in vitro than CD21lo transitional B cells. In contrast, the CD21lo subset expressed elevated levels of LEF1, a transcription factor highly expressed by immature lymphocytes, and produced higher amounts of autoreactive Ab. These phenotypic, functional, and molecular features suggest that CD21lo transitional B cells are less mature than the CD21hi subset. This was confirmed by analyzing X-linked agammaglobulinemia patients and the kinetics of B-cell reconstitution after stem cell transplantation, which revealed that the development of CD21lo transitional B cells preceded that of CD21hi transitional cells. These findings provide important insights into the process of human B-cell development and have implications for understanding the processes underlying perturbed B-cell maturation in autoimmune and immunodeficient conditions.

Engagement of cytokine receptors by specific ligands activate Janus kinase–signal transducer and activator of transcription (STAT) signaling pathways. The exact roles of STATs in human lymphocyte behavior remain incompletely defined. Interleukin (IL)-21 activates STAT1 and STAT3 and has emerged as a potent regulator of B cell differentiation. We have studied patients with inactivating mutations in STAT1 or STAT3 to dissect their contribution to B cell function in vivo and in response to IL-21 in vitro. STAT3 mutations dramatically reduced the number of functional, antigen (Ag)-specific memory B cells and abolished the ability of IL-21 to induce naive B cells to differentiate into plasma cells (PCs). This resulted from impaired activation of the molecular machinery required for PC generation. In contrast, STAT1 deficiency had no effect on memory B cell formation in vivo or IL-21–induced immunoglobulin secretion in vitro. Thus, STAT3 plays a critical role in generating effector B cells from naive precursors in humans. STAT3-activating cytokines such as IL-21 thus underpin Ag-specific humoral immune responses and provide a mechanism for the functional antibody deficit in STAT3-deficient patients.

Purpose: Predictive biomarkers are required to identify patients who may benefit from the use of BH3 mimetics such as ABT-263. This study investigated the efficacy of ABT-263 against a panel of patient-derived pediatric acute lymphoblastic leukemia (ALL) xenografts and utilized cell and molecular approaches to identify biomarkers that predict in vivo ABT-263 sensitivity. Experimental Design: The in vivo efficacy of ABT-263 was tested against a panel of 31 patient-derived ALL xenografts composed of MLL-, BCP-, and T-ALL subtypes. Basal gene expression profiles of ALL xenografts were analyzed and confirmed by quantitative RT-PCR, protein expression and BH3 profiling. An in vitro coculture assay with immortalized human mesenchymal cells was utilized to build a predictive model of in vivo ABT-263 sensitivity. Results: ABT-263 demonstrated impressive activity against pediatric ALL xenografts, with 19 of 31 achieving objective responses. Among BCL2 family members, in vivo ABT-263 sensitivity correlated best with low MCL1 mRNA expression levels. BH3 profiling revealed that resistance to ABT-263 correlated with mitochondrial priming by NOXA peptide, suggesting a functional role for MCL1 protein. Using an in vitro coculture assay, a predictive model of in vivo ABT-263 sensitivity was built. Testing this model against 11 xenografts predicted in vivo ABT-263 responses with high sensitivity (50%) and specificity (100%). Conclusion: These results highlight the in vivo efficacy of ABT-263 against a broad range of pediatric ALL subtypes and shows that a combination of in vitro functional assays can be used to predict its in vivo efficacy. Clin Cancer Res; 20(17); 4520–31. ©2014 AACR.

Item does not contain fulltext BACKGROUND: Mutations in the SP110 gene result in infantile onset of the autosomal recessive primary immunodeficiency disease veno-occlusive disease with immunodeficiency syndrome (VODI), which is characterized by hypogammaglobulinemia, T-cell dysfunction, and a high frequency of hepatic veno-occlusive disease. OBJECTIVES: We sought to further characterize the clinical features, B-lineage cellular immunologic findings, and molecular pathogenesis of this disorder in 9 patients with new diagnoses, including 4 novel mutations from families of Italian, Hispanic, and Arabic ethnic origin. METHODS: Methods used include clinical review; Sanger DNA sequencing of the SP110 gene; determination of transfected mutant protein function by using immunofluorescent studies in Hep-2 cells; quantitation of B-cell subsets by means of flow cytometry; assessments of B-cell function after stimulation with CD40 ligand, IL-21, or both; and differential gene expression array studies of EBV-transformed B cells. RESULTS: We confirm the major diagnostic criteria and the clinical utility of SP110 mutation testing for the diagnosis of VODI. Analysis of 4 new alleles confirms that VODI is caused by reduced functional SP110 protein levels. Detailed B-cell immunophenotyping demonstrated that Sp110 deficiency compromises the ability of human B cells to respond to T cell-dependent stimuli and differentiate into immunoglobulin-secreting cells in vitro. Expression microarray studies have identified pathways involved in B-lymphocyte differentiation and macrophage function. CONCLUSION: These studies show that a range of mutations in SP110 that cause decreased SP110 protein levels and impaired late B-cell differentiation cause VODI and that the condition is not restricted to the Lebanese population.

T follicular helper (T(FH)) cells are a specialized subset of CD4(+) T cells that localize to B-cell follicles, where they are positioned to provide help for the induction of optimal humoral immune responses. Key features of T(FH) cells are the expressions of CXCR5, ICOS, interleukin (IL)-21 and BCL-6. The requirements for human T(FH) cell development are unknown. Here we show that IL-6, IL-12, IL-21 and IL-23 are capable of inducing IL-21 expression in naïve CD4(+) T cells isolated from human tonsils, peripheral blood and cord blood. However, only IL-12 induced sustained expressions of CXCR5 and ICOS on these activated naïve CD4(+) T cells, and endowed them with the ability to provide increased help to B cells for their differentiation into immunoglobulin-secreting cells. The effects of IL-12 were independent of interferon-gamma and T-bet, and associated with upregulation of BCL-6 expression. Thus, these cytokines, particularly IL-12, are likely to act at an early stage during dendritic cell-mediated priming of naïve CD4(+) T cells into a T(FH) cell fate, and thus underpin antibody-mediated immunity.

Targeting the apoptosis pathway with BH3 mimetics such as ABT-263 (navitoclax) and ABT-199 is an appealing strategy for cancer therapy. While the Bcl-2/Bcl-w/Bcl-xL inhibitor navitoclax has shown promising activity in adults with lymphoid malignancies and in preclinical models of pediatric acute lymphoblastic leukemia (ALL), its application in pediatric patients has been limited by Bcl-xL-mediated thrombocytopenia. The specific Bcl-2 inhibitor ABT-199 has shown remarkable efficacy against adult chronic lymphocytic leukemia in recent clinical trials, although its activity against pediatric ALL is yet to be tested. The aim of this study was to evaluate the in vivo efficacy of ABT-199 against a large panel of pediatric ALL patient-derived xenografts (PDXs), and to identify biomarkers predictive of ABT-199 response. Immune-deficient (NOD/SCID or NSG) mice inoculated with PDXs derived from patients with infant ALL harboring rearrangement of the Mixed Lineage Leukemia (MLL) oncogene (infant MLL-ALL, n = 4), B-cell precursor ALL (BCP-ALL, n = 6), BCP-ALL categorized as Ph-like (n = 4), T-cell ALL (T-ALL, n = 4) or early T-cell precursor ALL (ETP-ALL, n = 2) were treated with ABT-199 (100 mg/kg x 21 days, p.o.) or vehicle control. Responses were assessed by time to event measurements or stringent objective response criteria modeled after the clinical setting. ABT-199 significantly delayed the progression of 12/20 PDXs by between 0.4 and 28 days, and elicited objective responses in 6/20 (30%) of PDXs (4 complete responses and 2 partial responses). No objective responses were observed in the T-ALL or ETP-ALL PDXs. By comparison, navitoclax administered on the same dose and schedule as ABT-199 elicited objective responses in 19/31 (61%) of PDXs derived from the same pediatric ALL subtypes. Analysis of basal gene and protein expression revealed that high Bcl-xL and low Bcl-2 expression were significantly associated with in vivo ABT-199 resistance. Moreover, the Bcl-2/Bcl-xL gene (P = 0.03) and protein (P = 0.002) expression ratios were significantly elevated in PDXs that responded to ABT-199 in vivo compared with non-responders. Notably, Mcl-1 expression at the gene or protein level showed no significant correlation with in vivo ABT-199 sensitivity. In conclusion, the inferior objective response rate observed for ABT-199 (30%) compared with navitoclax (61%) indicates that pediatric ALL PDXs are less dependent on Bcl-2 for cell survival compared with adult chronic lymphocytic leukemia. Moreover, Bcl-xL appears to be a more significant ABT-199 resistance factor than Mcl-1 in pediatric ALL. While ABT-199 has the potential to exert significant efficacy in the treatment of aggressive and chemoresistant pediatric ALL, the prospective identification of patients who might benefit from such treatment is of paramount importance. Supported by NCI NO1CM42216. Citation Format: Santi Suryani, Kathryn Evans, Jennifer Richmond, Alissa Robbins, Lauryn Bracken, Raushan Kurmasheva, Peter J. Houghton, Malcolm A. Smith, Richard B. Lock. Evaluation of the Bcl-2 inhibitor ABT-199 in xenograft models of acute lymphoblastic leukemia by the pediatric preclinical testing program. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3276. doi:10.1158/1538-7445.AM2015-3276

ThIL-17 (IL-17+/IFN-gamma-) cell lines are significantly more encephalitogenic than Th1 (IL-17-/IFN-gamma+) cell lines in adoptive transfer EAE models. In actively induced EAE short ex vivo peptide stimulation identifies an IL-17+/IFN-gamma+ population of CD4+ CNS-infiltrating MOG35-55-specific T cells, which outnumber IL-17+/IFN-gamma- cells by approximately 3:1 as disease develops. A decrease in numbers of IL-17+/IFN-gamma+ cells following in vitro culture is accompanied by an increase in IL-17-/IFN-gamma+ cell numbers. Together these ex vivo and in vitro observations imply that the Th1 lineage is more encephalitogenic than is suggested by adoptive transfer of Th1 (IL-17-/IFN-gamma+) cell lines which have been terminally differentiated in vitro.

Introduction: Manipulation of the mitochondrial apoptosis pathway is an appealing strategy for cancer treatment using small molecule BH3 mimetics such as ABT-737, ABT-263 and ABT-199. Defining a reliable cell or molecular signature that indicates a particular cancer's susceptibility to these drugs is a high priority to optimize their use for effective cancer chemotherapy. The goal of this study was to identify cell or molecular biomarkers predictive of the in vivo responses of pediatric acute lymphoblastic leukemia (ALL) xenografts established in immune-deficient (NOD/SCID) mice to single-agent ABT-263 treatment. Methods: The in vivo efficacy of ABT-263 (100 mg/kg x 21 days) was assessed against 31 patient-derived ALL xenografts derived from infant ALL with rearrangement of the Mixed Lineage Leukemia (MLL) oncogene (infant MLL-ALL, n=9), B-cell precursor (BCP)-ALL (n=7) and T-cell ALL (T-ALL, n=15) patients. Engraftment and drug responses were assessed by enumeration of the proportion of human versus mouse CD45+ cells in the peripheral blood. Anti-leukemic efficacy was assessed using an objective response measure modeled after the clinical setting, as well as the median event-free survival (EFS) of treated or control groups post-treatment. Three methods were applied to identify correlates of in vivo ABT-263 responses: (1) analysis of differentially expressed genes by gene expression profiling (GEP, Illumina HT12 BeadChips); (2) functional assessment of the mitochondrial priming status (BH3 profiling); (3) in vitro responses to single-agent ABT263 using a co-culture system with immortalized (hTERT) human mesenchymal stromal cells. Results: ABT-263 showed impressive single-agent efficacy across all three ALL subtypes, with 29 of 31 xenografts exhibiting significant progressive delays (range: 3.1 – 78 days), and 19 achieving Objective Responses (3 Maintained Complete Responses, 11 Complete Responses, and 5 Partial Responses). GEP showed that MCL1 exhibited the strongest correlation with in vivo ABT-263 sensitivity amongst BCL2 family members across the xenograft panels. Moreover, MCL1 protein function, assessed via mitochondrial depolarization mediated by Noxa peptide, also significantly correlated with in vivo ABT-263 resistance. Using an in vitro co-culture assay and cell survival assessed by flow cytometry after ABT-263 exposure (0.001-10 µM, 72 h), a training set of 17 xenografts was used to build a prediction model for in vivo xenograft responses. Testing this model against 11 other xenografts for which the in vivo results were blinded demonstrated that the fraction of cell survival at 10 nM ABT-263 predicted the in vivo responses with high sensitivity (67%) and specificity (100%). Conclusions: ABT-263 exhibits broad in vivo efficacy against pediatric ALL xenografts with no apparent subtype specificity. Cell and molecular analysis revealed MCL1 to be an important determinant of in vivo ABT-263 sensitivity, while an in vitro co-culture cytotoxicity assay was able to predict in vivo sensitivity. These in-principle approaches could be used to predict the individual responses of pediatric ALL patients to second-generation BH3 mimetics such as ABT-199. Supported by NCI NO1CM42216. Citation Format: Santi Suryani, Hernan Carol, Viktoras Frimantas, Beat Bornhauser, Chintanu Sarmah, Triona Chonghaile, Kathryn Evans, Elise Tonna, Luke Jones, Anthony Letai, Jean-Pierre Bourquin, Peter J. Houghton, Malcolm A. Smith, Richard B. Lock. Cell and molecular determinants of in vivo efficacy of the BH3 mimetic ABT-263 against pediatric acute lymphoblastic leukemia xenografts. [abstract]. In: Proceedings of the AACR Special Conference on Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; Nov 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;74(20 Suppl):Abstract nr B26.