: How has research in cancer immunotherapy changed in the past decade and how have the technological developments contributed to this evolution?
AQ: Cancer immunotherapy encompasses a wide array of mechanisms and approaches, ranging from cellular therapy to checkpoint blockade inhibitors including antibody- (anti-PD1) based therapies and vaccines. As we have learned more about these mechanisms and broadened the choices we have for new therapies, the cancer therapy landscape has grown to rely on immune-based treatments for certain cancers.
Genomic technologies, mass spectrometry, flow cytometry, and bioinformatics have played big roles in enabling these advances. Genomic innovations, for example, have improved the molecular research that goes into identifying targets for cell therapy and elevated levels of PD1 or other markers. More recently, the ability to identify target molecules that could be used in effective CAR T-cell development is better enabled using cell-based technologies like mass spectrometry and mass and flow cytometry.
The goal in applying many of these technologies becomes the same—to get the immune system working for the patient. T-cell receptor sequencing and the use of suspension-based cytometry or imaging modalities to monitor the immune system once cells are transferred back into a patient aid in assessing efficacy of different treatments. By refining these tools and ensuring they meet the required levels of sensitivity and reproducibility for adequate measurement, it has become possible to truly gauge success of these novel immunotherapies.
: What are some of the biggest hurdles/challenges facing researchers in this field and do you think they are being adequately addressed?
AQ: We need to understand why immunotherapy works better in certain malignancies compared to others. This is just one of many questions facing researchers that advanced molecular tools can help answer. There is also an increased need to look at many samples quickly, necessitating improvements in speed and perhaps resolution of certain technologies. For instance, only within the last couple of years have we started seeing how the use of high-multiplex imaging can support immunotherapy research and development, as evidenced by the multiple presentations focusing on imaging at the Society for Immunotherapy of Cancer 2019 meeting.
To obtain biological insights, there are many elements of the microenvironment to consider, such as large areas of stroma, vascularization, nutrients in blood flow, fibrotic regions, and various immune cell phenotypes and interactions. While suspension-based technology can give us some answers, high-dimensional imaging data could ultimately provide a more complete picture.
To understand this complexity using imaging approaches, two key needs must be addressed. First, better segmentation of a high-multiplex image could provide a more accurate picture of what cell types are present in a sample. The ability to segment single cells allows for the identification of the different cells in a tissue including cancer and immune cells as well as stroma, vasculature, and other important structural components of a tumor. Second, new computational approaches that can efficiently analyze high-dimensional imaging data must evolve with the increased volumes of information generated in high-plex data sets. Flow cytometry analysis has improved cell enumeration, but there is little support for looking at cell function simultaneously. This provides an incomplete picture, excluding insights on the role of cytokines with that of immune cells, for example. Seamless analysis that improves the ability to look at these functions at the same time would help progress immunotherapy research.
: Are there technological solutions that are currently being developed that you are excited about?
AQ: Advances in imaging, in particular, are accelerating our understanding of not only cell repertoire but also cell function, especially in the context of spatial localization. Visualizing molecular phenotypes and integrating data using bioinformatics solutions allows us to extract meaning from large datasets. With qualitative data, we can put together concepts. To further expand what we can do with respect to therapies, we need to be more quantitative.
Changing the course of how cancer is treated requires a comprehensive understanding of complex cellular phenotypes and their interrelationships in the spatial context of the tumor microenvironment. Imaging Mass Cytometry™ (IMC™) empowers high-dimensional imaging, enabling deep interrogation of tissues and tumors at subcellular resolution to uncover tumor pathology, new biomarker correlations, and cell interactions. IMC has enabled unprecedented biological insights stemming from over 45 publications since the technology’s inception in 2017.
In terms of tissue analysis itself, improvements in cell capture are enhancing the quality of biomolecules used in genomics assays. For example, techniques like laser capture microdissection are not new, but recent advancements in the lasers used and in consumable caps support the collection of better genomics data from LCM.
: What are some of the new trends that you are seeing in this field? Will existing technology keep up with those trends?
AQ: Multimode spatial imaging is a growing trend in cancer immunotherapy research, expanding our methods for extracting data from immune monitoring studies and generating more data from each sample. Retrospective papers describe tissue architecture and cell phenotype, but quantitative imaging could contribute valuable data regarding the impact of a therapy on the tumor as it evolves. This is an exciting new area to be a part of—developing these tools that can enumerate molecules as well as look at proteins and RNA (e.g., abs + RNA scope), specific signaling molecules (metabolites), and drug distributions. Data from these approaches can create a true multi-omic environment at subcellular resolution. Convergence of relevant technologies will increase the complexity of research and analysis, but it also can provide so much more depth.
Clinical and translational cancer researchers are able to use genomic and proteomic high-throughput technologies for biomarker discovery, gene expression analysis, spatial analysis, and comprehensive investigation of any sample type from suspension or tissue. This diversity in approach enables more information to be taken from an individual experiment and new questions to be asked with each discovery.
: Are there gaps in current technology offerings for cancer immunotherapy? How do they relate to lack of instrumentation, technical know-how, data deluge, translational issues?
AQ: Currently, there is a need for more integrated data analytics and standardization for immune-based studies. The increased amounts of data generated from high-dimensional technologies rely on more sophisticated analysis platforms that can manage diverse data points within one dataset. The capabilities of software like CyTOF® Software v7.0 for IMC streamlines the selection and acquisition of multiple regions of interest from each slide and the registration of IMC images with H&E serial sections.
Standardization can be a significant issue due to variation between technicians at the bench or from the instruments themselves, both contributing to intra-assay as well as site-to-site variability. Historically, studies done with flow cytometry tend to require significant expertise to properly standardize multiple instruments in the same facility, much less at multiple sites. Studies using Fluidigm Maxpar® Direct™ Immune Profiling Assay™, which is specific for mass cytometry, have been demonstrated to minimize these inter- and intra-site differences and can help address these gaps.
: If you could change one thing to drive progress in this field what would that be?
AQ: Progress relies on the access to latest advances in technology, including technology platforms, workflows, analytical pipelines, and expertise. Often these capabilities are outside the scope of smaller research teams. Providing access to these capabilities through programs like the Therapeutic Insights Services team at Fluidigm enable broader use of the latest technologies in emerging research efforts.
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Information in this publication is subject to change without notice. Patent and license information: fluidigm.com/legalnotices. Trademarks: Fluidigm, the Fluidigm logo, Imaging Mass Cytometry, IMC, Maxpar Direct Immune Profiling Assay, Biomark and AccuLift are trademarks and/or registered trademarks of Fluidigm Corporation in the United States and/or other countries. ©2020 Fluidigm Corporation. All rights reserved. 5/2020.