Keratin 17 modulates the immune topography of pancreatic cancer

Background

The immune microenvironment impacts tumor growth, invasion, metastasis, and patient survival and may provide opportunities for therapeutic intervention in pancreatic ductal adenocarcinoma (PDAC). Although never studied as a potential modulator of the immune response in most cancers, Keratin 17 (K17), a biomarker of the most aggressive (basal) molecular subtype of PDAC, is intimately involved in the histogenesis of the immune response in psoriasis, basal cell carcinoma, and cervical squamous cell carcinoma. Thus, we hypothesized that K17 expression could also impact the immune cell response in PDAC, and that uncovering this relationship could provide insight to guide the development of immunotherapeutic opportunities to extend patient survival.

Methods

Multiplex immunohistochemistry (mIHC) and automated image analysis based on novel computational imaging technology were used to decipher the abundance and spatial distribution of T cells, macrophages, and tumor cells, relative to K17 expression in 235 PDACs.

Results

K17 expression had profound effects on the exclusion of intratumoral CD8 + T cells and was also associated with decreased numbers of peritumoral CD8 + T cells, CD16 + macrophages, and CD163 + macrophages (p < 0.0001). The differences in the intratumor and peritumoral CD8 + T cell abundance were not impacted by neoadjuvant therapy, tumor stage, grade, lymph node status, histologic subtype, nor KRAS, p53, SMAD4, or CDKN2A mutations.

Conclusions

Thus, K17 expression correlates with major differences in the immune microenvironment that are independent of any tested clinicopathologic or tumor intrinsic variables, suggesting that targeting K17-mediated immune effects on the immune system could restore the innate immunologic response to PDAC and might provide novel opportunities to restore immunotherapeutic approaches for this most deadly form of cancer.

Characterization of viscerofugal neurons in human colon by retrograde tracing and multi-layer immunohistochemistry

Background and Aims

Viscerofugal neurons (VFNs) have cell bodies in the myenteric plexus and axons that project to sympathetic prevertebral ganglia. In animals they activate sympathetic motility reflexes and may modulate glucose metabolism and feeding. We used rapid retrograde tracing from colonic nerves to identify VFNs in human colon for the first time, using ex vivo preparations with multi-layer immunohistochemistry.

Methods

Colonic nerves were identified in isolated preparations of human colon and set up for axonal tracing with biotinamide. After fixation, labeled VFN cell bodies were subjected to multiplexed immunohistochemistry for 12 established nerve cell body markers.

Results

Biotinamide tracing filled 903 viscerofugal nerve cell bodies (n = 23), most of which (85%) had axons projecting orally before entering colonic nerves. Morphologically, 97% of VFNs were uni-axonal. Of 215 VFNs studied in detail, 89% expressed ChAT, 13% NOS, 13% calbindin, 9% enkephalin, 7% substance P and 0 of 123 VFNs expressed CART. Few VFNs contained calretinin, VIP, 5HT, CGRP, or NPY. VFNs were often surrounded by dense baskets of axonal varicosities, probably reflecting patterns of connectivity; VAChT+ (cholinergic), SP+ and ENK+ varicosities were most abundant around them. Human VFNs were diverse; showing 27 combinations of immunohistochemical markers, 4 morphological types and a wide range of cell body sizes. However, 69% showed chemical coding, axonal projections, soma-dendritic morphology and connectivity similar to enteric excitatory motor neurons.

Conclusion

Viscerofugal neurons are present in human colon and show very diverse combinations of features. High proportions express ChAT, consistent with cholinergic synaptic outputs onto postganglionic sympathetic neurons in prevertebral ganglia.

Advances in tissue-based imaging: impact on oncology research and clinical practice

INTRODUCTION

Tissue-based imaging has emerged as a critical tool in translational cancer research and is rapidly gaining traction within a clinical context. Significant progress has been made in the digital pathology arena, particularly in respect of brightfield and fluorescent imaging. Critically, the cellular context of molecular alterations occurring at DNA, RNA, or protein level within tumor tissue is now being more fully appreciated. Moreover, the emergence of novel multi-marker imaging approaches can now provide unprecedented insights into the tumor microenvironment, including the potential interplay between various cell types.

AREAS COVERED

This review summarizes the recent developments within the field of tissue-based imaging, centering on the application of these approaches in oncology research and clinical practice.

EXPERT OPINION

Significant advances have been made in digital pathology during the last 10 years. These include the use of quantitative image analysis algorithms, predictive artificial intelligence (AI) on large datasets of H&E images, and quantification of fluorescence multiplexed tissue imaging data. We believe that new methodologies that can integrate AI-derived histologic data with omic data, together with other forms of imaging data (such as radiologic image data), will enhance our ability to deliver better diagnostics and treatment decisions to the cancer patient.

Recent Advances in Pathology: the 2019 Annual Review Issue of The Journal of Pathology

In this Annual Review Issue of The Journal of Pathology, we present 15 invited reviews on topical aspects of pathology, ranging from the impacts of the microbiome in human disease through mechanisms of cell death and autophagy to recent advances in immunity and the uses of genomics for understanding, classifying and treating human cancers. Each of the reviews is authored by experts in their fields and our intention is to provide comprehensive updates in specific areas of pathology in which there has been considerable recent progress. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Highly immunosuppressive HLADRhi regulatory T cells are associated with unfavorable outcomes in cervical squamous cell carcinoma

Regulatory T cells (Tregs) are crucial for the maintenance of peripheral tolerance, but they also limit beneficial responses through cancer-induced immunoediting. The roles of Treg subsets in cervical squamous cell carcinoma (CSCC) are currently unknown. Here, we aimed to perform an extensive study with an increased resolution of the Treg compartment in the peripheral blood and tumor tissues of CSCC patients. We first identified that an HLADR^hi Treg population in the peripheral blood was significantly increased in CSCC patients compared to precancer patients and healthy donors. We found that HLADR^hi Tregs express high levels of a panel of inhibition and activation markers and the TCR-responsive transcription factors BATF and IRF4. However, this Treg subset showed reduced calcium influx after TCR crosslinking. In addition, HLADR^hi Tregs are highly proliferative and vulnerable to apoptosis. Further studies demonstrated that the HLADR^hi Tregs display high levels of suppressive activity. Quantitative multiplexed immunohistochemistry revealed that an increase in the number of tumor-infiltrating HLADR^hi Tregs is associated with unfavorable classical risk parameters of advanced disease stage and stromal invasion. Context-based quantification revealed that a high frequency of stromal HLADR^hi Tregs in patients is significantly associated with worse progression-free survival. In the current study, we characterized a population of highly activated and immunosuppressive HLADR^hi Tregs in CSCC patients. An increased HLADR^hi Treg frequency may be a potential biomarker to stratify CSCC patients and evaluate therapeutic efficacies in personalized immuno-oncology studies.

Flex-Array® - a novel multi-well vessel system for the immobilization and multi-modal testing of intact formalin-fixed paraffin-embedded (FFPE) cells or tissues

Flex-Array® is a novel multi-well system that extends the key features of current high-performance microscope slides used in advanced staining techniques. The Flex-Array® system facilitates the immobilization of FFPE cell or tissue sections onto a multi-well array for the subsequent performance of single analyte (IHC) or multiplexed immunohistochemistry (MIHC). Additionally, the Flex-Array® device is compatible with fluorescent and colorimetric in situ hybridization (FISH) and adds new capabilities such as replicate analysis, quantitative ELISA-like assays and microdissection-free nucleic acid extraction. The Flex-Array® facilitates rapid, contextually rich and high-precision multi-modal analysis of FFPE cells and tissues at a significant reduction in testing, data acquisition and analysis costs.

New tools for pathology: a user's review of a highly multiplexed method for in situ analysis of protein and RNA expression in tissue

Tumor cell heterogeneity and tumor cell-stromal interactions are being explored as determinants of disease progression and treatment resistance in solid tumor and hematological malignancies. As such, tools simultaneously capable of highly multiplexed profiling of tissues' protein and RNA content, as well as interrogation of rare or single cells, are required to precisely characterize constituent tumor cell populations, infiltrating lymphocytes and stromal elements. Access to spatial relationships will enable more precise characterization of tumors, support patient stratification and may help to identify novel drug targets. Multiple platforms are being developed to address these critical unmet needs. The NanoString digital spatial profiling (DSP) platform enables highly multiplexed, spatial assessment of protein and/or RNA targets in tissues by detecting oligonucleotide barcodes conjugated via a photocleavable linker to primary antibodies or nucleic acid probes. Although this platform enables high-dimensional spatial interrogation of tissue protein and RNA expression, a detailed understanding of its composition, function and chemistry is advisable to guide experimental design and data interpretation. The purpose of this review is to provide an independent, comprehensive description of the DSP technology, including an overview of NanoString's capture and antibody barcode conjugation chemistries, experimental workflow, data output and analysis methods. The DSP technology will be discussed in the context of other highly multiplexed immunohistochemistry methods, including imaging mass cytometry and multiplexed ion beam imaging, to inform potential users of the advantages and limitations of each. Additional issues such as preanalytical variability, sampling and specimen adequacy will be considered with respect to the platforms to inform potential experimental design. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

PD-L1 expression is a prognostic factor in subgroups of gastric cancer patients stratified according to their levels of CD8 and FOXP3 immune markers

Current studies aiming at identifying single immune markers with prognostic value have limitations in the context of complex antitumor immunity and cancer immune evasion. Here, we show how the integration of several immune markers influences the predictions of prognosis of gastric cancer (GC) patients. We analyzed Tissue Microarray (TMA) by multiplex immunohistochemistry and measured the expression of immune checkpoint molecule PD-L1 together with antitumor CD8 T cells and immune suppressive FOXP3 Treg cells in a cohort of GC patients. Unsupervised hierarchical clustering analysis of these markers was used to define correlations between CD8 T, FOXP3 Treg and PD-L1 cell densities. We found that FOXP3 and PD-L1 densities were elevated while CD8 T cells were decreased in tumor tissues compared to their adjacent normal tissues. However, patient stratification based on each one of these markers individually did not show significant prognostic value on patient survival. Conversely, combination of the ratios of CD8/FOXP3 and CD8/PD-L1 enabled the identification of patient subgroups with different survival outcomes. As such, high densities of PD-L1 in patients with high CD8/FOXP3 and low CD8/PD-L1 ratios correlated with increased survival. Collectively, this work demonstrates the need for the integration of several immune markers to obtain more meaningful survival prognosis and patient stratification. In addition, our work provides insights into the complex tumor immune evasion and immune regulation by the tumor-infiltrating effector and suppressor cells, informing on the best use of immunotherapy options for treating patients.