A monoclonal antibody against neurofilament protein specifically labels a subpopulation of rat sensory neurones

A monoclonal antibody (RT97) against neurofilament protein specifically and exclusively labelled a subpopulation of rat dorsal root ganglion (DRG) neurones. For seven ganglia (L4 and T13) studied quantitatively the frequency distribution histograms of the size of labelled cells could be fitted by a single normal distribution whose parameters were extremely close to those of the normally distributed large light cell population in that ganglion. On this basis and on the basis of a statistical analysis of the results it was suggested that this antibody can be used as a much needed specific label for the large light population of neurones in rat DRGs. The small dark neurone population was not labelled by this antibody. In one ganglion the subjective analysis of whether each neurone was labelled or not was directly compared with microdensitometric measurements of reaction product intensity. This analysis supported the above conclusion, and furthermore no subdivisions of the labelled population were apparent on the basis of neuronal size plotted against intensity of the reaction product. Other neuronal cell bodies strongly labelled by this antibody were found in association with small unlabelled neurones not only in DRGs, but also in the trigeminal ganglion, the vagal ganglia, and the mesencephalic V nucleus, all of which are made up of primary afferent neurones and all of which are completely or partially derived from the neural crest. Sympathetic and central nervous system neuronal cell bodies were unlabelled or occasionally very lightly labelled although immunoreactive fibres abound in the central nervous system.

Monoclonal antibodies against human T lymphocytes label Purkinje neurones of many species

Conventional antibodies have long been used in an attempt to produce specific neural markers. Such markers would be invaluable for studying the structural organization and development of the nervous system. Unfortunately, they have not been found to discriminate satisfactorily between neuronal subpopulations. Recent developments of the hybridoma technique, however, promise to provide monoclonal antibodies of adequate specificity. Such antibodies have already generated and shown to be capable of distinguishing between individual neurones of the leech nervous system. We report here two monoclonal antibodies which, although generated against human T cells, react exclusively with Purkinje cells in the vertebrate central nervous system (CNS). This new specificity arose out of a fortuitous observation made during examination of the lymphocyte infiltration of human cerebellar tumours with the monoclonal antibody, UCHT1. Although widely used as a T-cell marker, its reaction with neural tissue has not hitherto been described. To our knowledge, this is the first description of a monoclonal antibody which recognises discrete neuronal population in the vertebrate brain.

Biological characterization and clinical applications of a monoclonal antibody recognizing an antigen restricted to neuroectodermal tissues

The monoclonal antibody UJ13A was raised following immunization of mice with human foetal brain and subsequent somatic cell hyridization of spleen cells with the mouse myeloma cell line P3-X63-AG8-653. The antibody is of the IgG1 subclass and has been shown by indirect immunofluorescence studies on normal foetal, paediatric and adult tissues to selectively bind to most tissues of neuroectodermal origin. Many tumours of neural origin also express the UJ13A antigen and the reagent can be used to distinguish primary intracranial neural tumours from secondary carcinomas and lymphomas. UJ13A is also useful as one of a panel of reagents employed for the identification of metastatic spread of neuroblastoma cells to bone marrow and cerebrospinal fluid. Knowledge of the full spectrum of normal and malignant tissues binding UJ13A suggests that the antibody may have a role in the radioimmunolocalization of neuronal tumours such as neuroblastoma.

Obesity Contributes to Ovarian Cancer Metastatic Success through Increased Lipogenesis, Enhanced Vascularity, and Decreased Infiltration of M1 Macrophages

Epithelial ovarian cancer (EOC) is the leading cause of death from gynecologic malignancy, with high mortality attributable to widespread intraperitoneal metastases. Recent meta-analyses report an association between obesity, ovarian cancer incidence, and ovarian cancer survival, but the effect of obesity on metastasis has not been evaluated. The objective of this study was to use an integrative approach combining in vitro, ex vivo, and in vivo studies to test the hypothesis that obesity contributes to ovarian cancer metastatic success. Initial in vitro studies using three-dimensional mesomimetic cultures showed enhanced cell-cell adhesion to the lipid-loaded mesothelium. Furthermore, in an ex vivo colonization assay, ovarian cancer cells exhibited increased adhesion to mesothelial explants excised from mice modeling diet-induced obesity (DIO), in which they were fed a "Western" diet. Examination of mesothelial ultrastructure revealed a substantial increase in the density of microvilli in DIO mice. Moreover, enhanced intraperitoneal tumor burden was observed in overweight or obese animals in three distinct in vivo models. Further histologic analyses suggested that alterations in lipid regulatory factors, enhanced vascularity, and decreased M1/M2 macrophage ratios may account for the enhanced tumorigenicity. Together, these findings show that obesity potently affects ovarian cancer metastatic success, which likely contributes to the negative correlation between obesity and ovarian cancer survival.

Use of monoclonal antibody panel to identify malignant cells in cerebrospinal fluid

A panel of monoclonal antibodies was systematically applied to cerebrospinal fluid from 17 patients with suspected neoplastic meningitis and the results were compared with those obtained from routine cytological preparations. The antibody panel consisted of markers for neuroectodermal tissue ( UJ13A ), epithelial cytokeratin ( LE61 ), leucocytes ( 2D1 ), and neoplastic neuroblasts ( UJ181 .4). Additional antibodies were used to refine diagnosis when indicated. Cerebrospinal fluid samples from 12 patients with non-neoplastic conditions were used as controls. The use of monoclonal antibodies gave a positive diagnosis in 16/17 cases and the cells were accurately categorised as carcinoma (5/6 cases), neuroectodermal tumour (8/8 cases), and lymphoma (3/3 cases). In the 14 cases examined by routine cytology, malignant cells were reported in 10 cases and accurately categorised in only 3/14 cases. Immunocytological testing of cerebrospinal fluid with an antibody panel has greatly increased the accuracy with which malignant cells can be identified and categorised.

Immunohistological diagnosis of central nervous system tumours using a monoclonal antibody panel

A panel of seven monoclonal antibodies has been used to characterise 164 cerebral and spinal tumours. These reagents have enabled rapid and accurate diagnosis of tumours to be made, particularly in cases where standard techniques have proved equivocal. On the basis of characteristic antigenic profiles of tumours, it has been possible to distinguish between gliomas, meningiomas, schwannomas, medulloblastomas, neuroblastomas, choroid plexus tumours, various metastatic deposits, and primary brain lymphomas. The reagents used in the study comprise antibodies binding to (a) most neuroectodermally derived tissues and tumours (UJ13A), (b) fetal brain and tumours of neuroblastic origin (UJ181.4), (c) schwannomas, normal and neoplastic neurones (UJ127.11), (d) glial cells (FD19), (e) epithelial cells (LE61), and (f) leucocytes (2D1). Some reagents, such as antibody A2B5, were less effective as diagnostic markers than originally suggested by previously described specificity. This monoclonal antibody reacted with both neuroectodermal and epithelial derived tumours. The panel of monoclonal antibodies was most useful in the diagnosis of tumours composed of small round cells, particularly lymphoma and neuroblastoma, but the pattern of reactivities allowed most of the central nervous system tumours to be accurately classified. This approach was a valuable adjunct to conventional histological techniques in about 20% of the cases examined.

Yeast interfering RNA larvicides targeting neural genes induce high rates of Anopheles larval mortality

Background

Although larviciding can reduce the number of outdoor biting malaria vector mosquitoes, which may help to prevent residual malaria transmission, the current larvicide repertoire is faced with great challenges to sustainability. The identification of new effective, economical, and biorational larvicides could facilitate maintenance and expansion of the practice of larviciding in integrated malaria vector mosquito control programmes. Interfering RNA molecules represent a novel class of larvicides with untapped potential for sustainable mosquito control. This investigation tested the hypothesis that short interfering RNA molecules can be used as mosquito larvicides.

Results

A small interfering RNA (siRNA) screen for larval lethal genes identified siRNAs corresponding to the Anopheles gambiae suppressor of actin (Sac1), leukocyte receptor complex member (lrc), and offtrack (otk) genes. Saccharomyces cerevisiae (baker’s yeast) was engineered to produce short hairpin RNAs (shRNAs) for silencing of these genes. Feeding larvae with the engineered yeasts resulted in silenced target gene expression, a severe loss of neural synapses in the larval brain, and high levels of larval mortality. The larvicidal activities of yeast interfering RNA larvicides were retained following heat inactivation and drying of the yeast into user-friendly tablet formulations that induced up to 100% larval mortality in laboratory trials.

Conclusions

Ready-to-use dried inactivated yeast interfering RNA larvicide tablets may someday be an effective and inexpensive addition to malaria mosquito control programmes and a valuable, biorational tool for addressing residual malaria transmission.

Electronic supplementary material

The online version of this article (10.1186/s12936-017-2112-5) contains supplementary material, which is available to authorized users.

The role of monoclonal antibodies in brain tumour diagnosis and cerebrospinal fluid (CSF) cytology

This paper reviews the diagnostic role of monoclonal antibody immunohistochemistry in a series of 189 brain tumour biopsies and 22 cases of neoplastic meningitis. The diagnostic monoclonal antibody panel, which includes markers for glial, neural, epithelial and lymphoid differentiation antigens, was used to test a wide variety of cerebral and spinal tumours by indirect immunofluorescence and immunoperoxidase techniques on unfixed frozen sections. Gliomas, meningiomas, schwannomas, medulloblastomas, choroid plexus tumours, cerebral lymphomas and metastatic carcinomas could all be reliably differentiated by means of their characteristic antigenics profiles, as defined by their patterns of reactivity with the antibody panel. Confident diagnosis was possible even in very poorly differentiated tumours and in biopsies distorted by surgical squeeze artefact, where paucity of morphological clues made diagnosis by conventional histological methods difficult or impossible. It was estimated that use of the antibody panel was responsible for, or made a significant contribution towards the final diagnosis in approximately 20% of cases. The monoclonal reagents were also found to be of great value in the detection and characterisation of neoplastic cells in CSF specimens from patients with malignant meningitis. Malignant cells were detected in 73% of cases and characterised in 16% of cases by routine cytological techniques. Employing monoclonal immunocytology however, these figures were improved to 95% and 95% respectively. Our findings suggest that patients with neoplastic meningitis can be spared prolonged investigation and inappropriate management by the early detection and characterisation of malignant cells in CSF using panels of monoclonal antibodies.

Monoclonal antibody 2C5: a marker for a subpopulation of small neurones in rat dorsal root ganglia

Monoclonal antibody 2C5 labels a subset of dorsal root ganglion neurones in the rat. The cell sizes of these neurones fall within the range for the small dark cell population and the antibody labels between a half and two-thirds of the neurones in this size range. A subpopulation of small neurones was also labelled in the trigeminal and vagal ganglia. Other sites of immunoreactivity in the central nervous system are the region of the substantia gelatinosa of the spinal cord, fibres in Lissauer's tract, the tractus solitarius and the tuberculum olfactorium. These sites are consistent with the antigen being expressed by the central processes of primary afferent neurones. It is suggested that the size distributions of 2C5-positive dorsal root ganglion neurones and the pattern of 2C5 immunoreactivity within the spinal cord indicate that the labelled cells may be neurones with peripheral C fibers. Outside the nervous system the antigen is expressed in a number of specific cell types within a variety of organs. These include some pancreatic acinar cells, parietal cells of the gastric mucosa, some cells in taste buds, Leydig cells of the testis, scattered cells in lymph nodes and lung alveoli, some renal tubules, the epithelial lining of the fallopian tube, the epithelium covering the ovary and certain cells in the basal layer of the epidermis.

Lure-and-Kill Yeast Interfering RNA Larvicides Targeting Neural Genes in the Human Disease Vector Mosquito Aedes aegypti

New mosquito control strategies are vitally needed to address established arthropod-borne infectious diseases such as dengue and yellow fever and emerging diseases such as Zika and chikungunya, all of which are transmitted by the disease vector mosquito Aedes aegypti. In this investigation, Saccharomyces cerevisiae (baker’s yeast) was engineered to produce short hairpin RNAs (shRNAs) corresponding to the Aedes aegypti orthologs of fasciculation and elongation protein zeta 2 (fez2) and leukocyte receptor cluster (lrc) member, two genes identified in a recent screen for A. aegypti larval lethal genes. Feeding A. aegypti with the engineered yeasts resulted in silenced target gene expression, disrupted neural development, and highly significant larval mortality. Larvicidal activities were retained following heat inactivation and drying of the yeast into tabular formulations that induced >95% mortality and were found to attract adult females to oviposit. These ready-to-use inactivated yeast interfering RNA tablets may one day facilitate the seamless integration of this new class of lure-and-kill species-specific biorational mosquito larvicides into integrated mosquito control programs.

Host Wnt5a Potentiates Microenvironmental Regulation of Ovarian Cancer Metastasis

The noncanonical Wnt ligand Wnt5a is found in high concentrations in ascites of women with ovarian cancer. In this study, we elucidated the role of Wnt5a in ovarian cancer metastasis. Wnt5a promoted ovarian tumor cell adhesion to peritoneal mesothelial cells as well as migration and invasion, leading to colonization of peritoneal explants. Host components of the ovarian tumor microenvironment, notably peritoneal mesothelial cells and visceral adipose, secreted Wnt5a. Conditional knockout of host WNT5A significantly reduced peritoneal metastatic tumor burden. Tumors formed in WNT5A knockout mice had elevated cytotoxic T cells, increased M1 macrophages, and decreased M2 macrophages, indicating that host Wnt5a promotes an immunosuppressive microenvironment. The Src family kinase Fgr was identified as a downstream effector of Wnt5a. These results highlight a previously unreported role for host-expressed Wnt5a in ovarian cancer metastasis and suggest Fgr as a novel target for inhibition of ovarian cancer metastatic progression.Significance: This study establishes host-derived Wnt5a, expressed by peritoneal mesothelial cells and adipocytes, as a primary regulator of ovarian cancer intraperitoneal metastatic dissemination and identifies Fgr kinase as novel target for inhibition of metastasis.

With Great Age Comes Great Metastatic Ability: Ovarian Cancer and the Appeal of the Aging Peritoneal Microenvironment

Age is one of the biggest risk factors for ovarian cancer. Older women have higher rates of diagnosis and death associated with the disease. In mouse models, it was shown that aged mice had greater tumor burden than their younger counterparts when intraperitoneally injected with ovarian tumor cells. While very few papers have been published looking at the direct link between ovarian cancer metastasis and age, there is a wealth of information on how age affects metastatic microenvironments. Mesothelial cells, the peritoneal extracellular matrix (ECM), fibroblasts, adipocytes and immune cells all exhibit distinct changes with age. The aged peritoneum hosts a higher number of senescent cells than its younger counterpart, in both the mesothelium and the stroma. These senescent cells promote an inflammatory profile and overexpress Matrix Metalloproteinases (MMPs), which remodel the ECM. The aged ECM is also modified by dysregulated collagen and laminin synthesis, increases in age-related crosslinking and increasing ovarian cancer invasion into the matrix. These changes contribute to a vastly different microenvironment in young and aged models for circulating ovarian cancer cells, creating a more welcoming “soil”.

Effect of histamine and prostaglandin E2 on the microcirculation in the skin

The response of the cutaneous microvasculature to two vasoactive mediators, histamine and prostaglandin E2, was measured by laser Doppler velocimetry. Four concentrations of histamine (1.01 to 65.1 X 10(-5) M, in fourfold dilutions) were injected intradermally into the forearms of six healthy subjects: Prostaglandin E2 (1.77 to 114.0 X 10(-8) M, also in fourfold dilutions) was injected several weeks later. The blood flow at the injection site was measured by laser Doppler velocimetry at five minute intervals until the response resolved. Both mediators produced hyperaemia with markedly accelerated cutaneous blood flow. Analysis of the dose response data showed that, for a given mediator, the differences in responses between subjects were not substantial and, in particular, that the kinetics of the decay of hyperaemia did not vary significantly between subjects. The response to histamine differed from that to Prostaglandin E2 in terms of time to maximum response, duration of maximum response and coefficient of decay.

Effect of topically applied local anaesthesia on histamine flare in man measured by laser Doppler velocimetry

The direct and indirect effects of histamine on the cutaneous microvasculature were measured by laser Doppler velocimetry. Histamine (6.51 x 10(-4) M) was injected intradermally into the forearms of eight healthy subjects following treatment with a topically applied local anaesthetic cream (EMLA) or equivalent placebo. The blood flow at the injection site (0 cm) and at 1 and 2 cm proximally was measured by laser Doppler velocimetry over 80 minutes. Analysis of the changes in magnitude of the hyperaemic responses with time showed no difference at the 0 and 1 cm sites, but a marked reduction was found at the 2 cm site following EMLA treatment (p less than 0.05). At all three sites the decay of the histamine-induced hyperaemia was faster following EMLA treatment than with placebo (p less than 0.04). The experiments showed that the indirect effect of histamine on the cutaneous microvasculature in the peripheral flare around the injection site was greatly diminished by prior application of EMLA cream and this supports the neurogenic hypothesis: pre-treatment with EMLA cream did not affect the development of hyperaemia and oedema at the site of histamine injection where the mediator acts directly on the cutaneous microvasculature.

Host obesity alters the ovarian tumor immune microenvironment and impacts response to standard of care chemotherapy

BACKGROUND

The majority of women with epithelial ovarian cancer (OvCa) are diagnosed with metastatic disease, resulting in a poor 5-year survival of 31%. Obesity is a recognized non-infectious pandemic that increases OvCa incidence, enhances metastatic success and reduces survival. We have previously demonstrated a link between obesity and OvCa metastatic success in a diet-induced obesity mouse model wherein a significantly enhanced tumor burden was associated with a decreased M1/M2 tumor-associated macrophage ratio (Liu Y et al. Can, Res. 2015; 75:5046-57).

METHODS

The objective of this study was to use pre-clinical murine models of diet-induced obesity to evaluate the effect of a high fat diet (HFD) on response to standard of care chemotherapy and to assess obesity-associated changes in the tumor microenvironment. Archived tumor tissues from ovarian cancer patients of defined body mass index (BMI) were also evaluated using multiplexed immunofluorescence analysis of immune markers.

RESULTS

We observed a significantly diminished response to standard of care paclitaxel/carboplatin chemotherapy in HFD mice relative to low fat diet (LFD) controls. A corresponding decrease in the M1/M2 macrophage ratio and enhanced tumor fibrosis were observed both in murine DIO studies and in human tumors from women with BMI > 30.

CONCLUSIONS

Our data suggest that the reported negative impact of obesity on OvCa patient survival may be due in part to the effect of the altered M1/M2 tumor-associated macrophage ratio and enhanced fibrosis on chemosensitivity. These data demonstrate a contribution of host obesity to ovarian tumor progression and therapeutic response and support future combination strategies targeting macrophage polarization and/or fibrosis in the obese host.

The effect of exposure of hospital employees to patients with tuberculosis on dermal reactivity to four new tuberculins

An early (6-8 h) erythematous response to Purified Protein Derivative and to sonicate antigens (new tuberculins) prepared from Mycobacterium tuberculosis, M. vaccae, M. scrofulaceum, and M. leprae occurred much more frequently amongst hospital employees exposed to patients with tuberculosis than amongst factory workers. Biopsies taken from the skin test sites at 48 h revealed a more intense inflammatory cell infiltrate in response to PPD and the sonicate of M. tuberculosis, but not to the antigens of the other mycobacteria, amongst the hospital employees thus indicating a degree of specificity. The early response appears to be directed towards species specific antigens, but not, apparently, to the same as those that elicit the 48 h reactions. The hospital employees also had higher peripheral blood B-cell counts and total IgG levels, suggestive of an adjuvant effect. It is postulated that the early reaction results from repeated exposure to tubercle bacilli and the possible nature of the reaction is discussed.

Measurement of cutaneous blood flow velocity in delayed hypersensitivity reactions in guinea pigs

The blood flow velocity in the skin of the flanks of guinea pigs can be measured precisely by laser Doppler velocimetry, provided the animal is mildly sedated. The probe holder can be attached to the shaved skin with cyanoacrylate glue and can be detached after completion of blood flow velocity measurements by application of acetone without harming the animal. The technique is pain-free and non-invasive: it can be used to make serial measurements on the same animal. The system has demonstrated hyperaemia in delayed-type responses to tuberculin PPD, ovalbumin and Keyhole Limpet Haemocyanin with immunological specificity. The time course of evolution and resolution of the vasomotor response accords with previous experience. The method can detect hyperaemia-inducing mediators in the supernatant of antigen or mitogen stimulated lymphocyte cultures and could be used for their bioassay.

Advanced Glycation End Products as a Potential Target for Restructuring the Ovarian Cancer Microenvironment: A Pilot Study

Ovarian cancer is the sixth leading cause of cancer-related death in women, and both occurrence and mortality are increased in women over the age of 60. There are documented age-related changes in the ovarian cancer microenvironment that have been shown to create a permissive metastatic niche, including the formation of advanced glycation end products, or AGEs, that form crosslinks between collagen molecules. Small molecules that disrupt AGEs, known as AGE breakers, have been examined in other diseases, but their efficacy in ovarian cancer has not been evaluated. The goal of this pilot study is to target age-related changes in the tumor microenvironment with the long-term aim of improving response to therapy in older patients. Here, we show that AGE breakers have the potential to change the omental collagen structure and modulate the peritoneal immune landscape, suggesting a potential use for AGE breakers in the treatment of ovarian cancer.

Another Wrinkle with Age: Aged Collagen and Intra-peritoneal Metastasis of Ovarian Cancer

Background

Age is the most significant risk factor for ovarian cancer (OvCa), the deadliest gynecologic malignancy. Metastasizing OvCa cells adhere to the omentum, a peritoneal structure rich in collagen, adipocytes, and immune cells. Ultrastructural changes in the omentum and the omental collagen matrix with aging have not been evaluated.

Aim

The aim of this study was to test the hypothesis that age-related changes in collagen in the ovarian tumor microenvironment promote OvCa metastatic success in the aged host.

Methods/Results

Young (3-6 months) and aged mice (20-23 months) were used to study the role of aging in metastatic success. Intra-peritoneal (IP) injection of ID8Trp53 ^-/- ovarian cancer cells showed enhanced IP dissemination in aged vs young mice. In vitro assays using purified collagen demonstrated reduced collagenolysis of aged fibers, as visualized using scanning electron microscopy (SEM) and quantified with a hydroxyproline release assay. Omental tumors in young and aged mice showed similar collagen deposition; however enhanced intra-tumoral collagen remodeling was seen in aged mice probed with a biotinylated collagen hybridizing peptide (CHP). In contrast, second harmonic generation (SHG) microscopy showed significant differences in collagen fiber structure and organization in omental tissue and SEM demonstrated enhanced omental fenestration in aged omenta. Combined SHG and Alexa Fluor-CHP microscopy in vivo demonstrated that peri-tumoral collagen was remodeled more extensively in young mice. This collagen population represents truly aged host collagen, in contrast to intra-tumoral collagen that is newly synthesized, likely by cancer associated fibroblasts (CAFs).

Conclusions

Our results demonstrate that tumors in an aged host can grow with minimal collagen remodeling, while tumors in the young host must remodel peri-tumoral collagen to enable effective proliferation, providing a mechanism whereby age-induced ultrastructural changes in collagen and collagen-rich omenta establish a permissive pre-metastatic niche contributing to enhanced OvCa metastatic success in the aged host.

Sex-dependent effects in the aged melanoma tumor microenvironment influence invasion and resistance to targeted therapy

There is documented sex disparity in cutaneous melanoma incidence and mortality, increasing disproportionately with age and in the male sex. However, the underlying mechanisms remain unclear. While biological sex differences and inherent immune response variability have been assessed in tumor cells, the role of the tumor-surrounding microenvironment, contextually in aging, has been overlooked. Here, we show that skin fibroblasts undergo age-mediated, sex-dependent changes in their proliferation, senescence, ROS levels, and stress response. We find that aged male fibroblasts selectively drive an invasive, therapy-resistant phenotype in melanoma cells and promote metastasis in aged male mice by increasing AXL expression. Intrinsic aging in male fibroblasts mediated by EZH2 decline increases BMP2 secretion, which in turn drives the slower-cycling, highly invasive, and therapy-resistant melanoma cell phenotype, characteristic of the aged male TME. Inhibition of BMP2 activity blocks the emergence of invasive phenotypes and sensitizes melanoma cells to BRAF/MEK inhibition.

In Vivo and Ex Vivo Analysis of Omental Adhesion in Ovarian Cancer

In vivo and ex vivo analyses of omental adhesion in ovarian cancer (OvCa) are necessary to understand the dynamics of OvCa metastasis. Here we describe methods to analyze OvCa omental adhesion, including in vivo and ex vivo fluorescent imaging, advanced microscopy, and histological techniques. The use of fluorescently tagged OvCa cells allows for omental tumor visualization and quantification in adhesion and tumor studies. Additionally, advanced microscopy modalities allow for visualization and multiplexed analysis of OvCa omental adhesion. Second harmonic generation microscopy permits the visualization and analysis of omental collagen, specifically the tumor-associated collagen signature that forms as the tumor progresses. Scanning electron microscopy is used for the observation of microscopic details between OvCa cells and the omentum, such as tunneling nanotubes or microvilli. Histological methods are used to investigate several intratumoral properties including visualizing tumor structure using hematoxylin and eosin stain; quantifying collagen with Masson's trichrome stain; analyzing collagen structure with a collagen hybridizing peptide; and identifying a number of markers including, but not limited to proliferation, immune cell types, adhesion molecules, and fibroblasts with immunohistochemistry. Both the in vivo and ex vivo imaging modalities and subsequent analysis can provide insight into the interaction of metastasizing OvCa cells and the omentum.

Aged fibroblast-derived extracellular vesicles promote angiogenesis in melanoma

Advancing age is a negative prognostic factor for cutaneous melanoma. However, the role of extracellular vesicles (EVs) within the melanoma tumor microenvironment (TME) has remained unexplored in the context of aging. While the size and morphology of the EVs isolated from young vs. aged fibroblasts remained unaltered, the contents of the protein cargo were changed. Aging reduced the expression of the tetraspanin CD9 in both the dermal fibroblasts and released EVs. CD9 is a crucial regulator of EV cargo sorting. Modulating the CD9 expression in fibroblasts was sufficient to alter its levels in EVs. Mass spectrometry analysis of EVs released by CD9 knockdown (KD) vs. control cells revealed a significant increase in angiopoietin-like protein 2 (ANGPTL2), an angiogenesis promoter. Analysis of primary endothelial cells confirmed increased sprouting under CD9 KD conditions. Together, our data indicate that aged EVs play an important role in promoting a tumor-permissive microenvironment.

Spatial multi-omics reveal intratumoral humoral immunity niches associated with tertiary lymphoid structures in pancreatic cancer immunotherapy pathologic responders

Pancreatic adenocarcinoma (PDAC) is a rapidly progressing cancer that responds poorly to immunotherapies. Intratumoral tertiary lymphoid structures (TLS) have been associated with rare long-term PDAC survivors, but the role of TLS in PDAC and their spatial relationships within the context of the broader tumor microenvironment remain unknown. We generated a spatial multi-omics atlas encompassing 26 PDAC tumors from patients treated with combination immunotherapies. Using machine learning-enabled H&E image classification models and unsupervised gene expression matrix factorization methods for spatial transcriptomics, we characterized cellular states within TLS niches spanning across distinct morphologies and immunotherapies. Unsupervised learning generated a TLS-specific spatial gene expression signature that significantly associates with improved survival in PDAC patients. These analyses demonstrate TLS-associated intratumoral B cell maturation in pathological responders, confirmed with spatial proteomics and BCR profiling. Our study also identifies spatial features of pathologic immune responses, revealing TLS maturation colocalizing with IgG/IgA distribution and extracellular matrix remodeling.

GRAPHICAL ABSTRACT

HIGHLIGHTS

Integrated multi-modal spatial profiling of human PDAC tumors from neoadjuvant immunotherapy clinical trials reveal diverse spatial niches enriched in TLS.TLS maturity is influenced by tumor location and the cellular neighborhoods in which TLS immune cells are recruited.Unsupervised machine learning of genome-wide signatures on spatial transcriptomics data characterizes the TLS-enriched TME and associates TLS transcriptomes with survival outcomes in PDAC.Interactions of spatially variable gene expression patterns showed TLS maturation is coupled with immunoglobulin distribution and ECM remodeling in pathologic responders.Intratumoral plasma cell and immunoglobin gene expression spatial dynamics demonstrate trafficking of TLS-driven humoral immunity in the PDAC TME.

Significance

We report a spatial multi-omics atlas of PDAC tumors from a series of immunotherapy neoadjuvant clinical trials. Intratumorally, pathologic responders exhibit mature TLS that propagate plasma cells into malignant niches. Our findings offer insights on the role of TLS-associated humoral immunity and stromal remodeling during immunotherapy treatment.