Genetic Engineering & Biotechnology News

JUL 2018

Genetic Engineering & Biotechnology News (GEN) is the world's most widely read biotech publication. It provides the R&D community with critical information on the tools, technologies, and trends that drive the biotech industry.

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Page 13 of 33

12 | JULY 2018 | Genetic Engineering & Biotechnology News | Aaron Goldman, Ph.D. The presence and activity of lymphocytes within a tumor is critical for determining the potential clinical response to cancer im- munotherapy, such as immune checkpoint blockade. Typically, tumors with poor T-cell- inflamed phenotypes, often referred to as "cold" tumors, are associated with a modest clinical response. High baseline infiltration of effector T-cell lymphocytes is considered "hot," and pa- tients are predicted to respond more favor- ably to treatment. However, patient-to-patient response and durability remains highly variable. Thus, we need further understanding of how the immune compartment changes in response to immunotherapies in individual patients. More specifically, there is a serious gap in available methods for studying lymphocyte infiltration, trafficking, and spatial heteroge- neity induced by different cancer immuno- therapies in individual patients. CANscript™ is an ex vivo human tumor model that recapitulates and preserves the na- tive, patient-autologous tumor microenviron- ment, including autologous patient-derived peripheral blood mononuclear cells (PBMCs). The CANscript live-tumor assay reliably rec- reates the tumor ecosystem, including micro- environment components such as the stroma, the vasculature, and the immune contexture. In this system, therapies are tested by quan- titatively assessing phenotypic response to therapy via a multidimensional set of assays, leading to a response-predictive score. To train this platform, phenotypic re- sponse to treatment ex vivo was performed on ~2000 patients who received the same Human Tumor Platform Recreates the Dynamic Microenvironment Profiling an Active Tumor Immune Microenvironment, Ex Vivo Drug Discovery Tutorial ing and imaging step, a record of single-cell deposition is created, and this iterative pro- cess is repeated several times over per well to ensure that a final plate with a high occu- pancy of single wells is achieved. "This gives you documentation for regulatory assurance that colonies growing in wells resulted from a single starting cell," says Ian Taylor, Ph.D., sales and marketing director, Solentim. "For biotherapeutics, the FDA requires assurance of clonality in the form of docu- mentation. VIPS offers options for fluores- cence validation and Clonality Report software, which is a documentation package for the clones of interest," Dr. Taylor notes. This Clonality Report includes all the spe- cific requirements from the FDA guidance including whole-well image, location of the single-cell feature, zoom-in of the single-cell feature for day zero, and subsequent daily im- aging along with full audit trail of those clones. "Once wells and time points have been se- lected, a report is automatically generated as a PDF or PowerPoint. This report can be in- cluded as part of an IND submission, given to the cell banking or manufacturing group, or provided to a CMDO client as part of the cell line project deliverables," Dr. Taylor explains. Downstream Considerations For applications that require single-cell cloning, challenges include survival of indi- vidual clones and verification of monoclonal- ity. Also, single-cell cloning has historically re- quired the use of serum, which is undesirable for many downstream applications. "We invest a great deal in optimizing our culture media to support cells during single- cell cloning, a key yet stressful stage of cell line development," says Grace Tharmara- jah, Ph.D., product marketing manager for research and development at Stemcell Tech- nologies. "We produce media that promote the single-cell survival and increased cloning efficiency of human ES and iPS cells (CloneR™), as well as hybridomas, CHO, HEK-293, and other mammalian cell lines (ClonaCell™). CloneR™ is a serum-free supplement, and ClonaCell™ media for- mulations include serum-containing, serum- free, animal component–free, and animal origin–free options," Dr. Tharmarajah adds. Stemcell also offers specialized culture- ware (AggreWell™) that can be used to compartmentalize and image the cells during clonal development to verify clonality of the resulting colonies. It is critical that the quality of the cloned cells, with respect to karyotype, for example, is not altered during the cloning process. Single-cell cloning remains challenging for its practitioners, but individual process adaptations and evolving technology con- tinues to make it more accessible. Single-Cell Cloning Continued from page 11 Figure 1. CANscript™ is a multidimensional live-tissue platform that recreates the patient's unique tumor microenvironment ex vivo. It can personalize patient care by predicting how individual patients will respond to anticancer therapy. Figure 2. Development of an ex vivo tumor-infiltrating lymphocyte (TIL) model. 1: Fresh tumor-containing stroma is harvested along with patient-autologous peripheral blood lymphocytes, which have been "prelabeled." 2: CANscript™ is performed using the co-culture of tumor/stroma biopsy with prelabeled lymphocytes 3: Tumor tissue is harvested at 24-hour intervals, dissociated, and labeled for flow cytometric analysis. Intrinsic TILs and dynamic TILs (infiltrated during culture) are captured.

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