Investigating the tumor-immune microenvironment through extracellular vesicles from frozen patient biopsies and 3D cultures

Abstract

Melanomas are highly immunogenic tumors that have been shown to activate the immune response. Nonetheless, a significant portion of melanoma cases are either unresponsive to immunotherapy or relapsed due to acquired resistance. During melanomagenesis, melanoma and immune cells undergo immunomodulatory mechanisms that aid in immune resistance and evasion. The crosstalk within melanoma microenvironment is facilitated through the secretion of soluble factors, growth factors, cytokines, and chemokines. In addition, the release and uptake of secretory vesicles known as extracellular vesicles (EVs) play a key role in shaping the tumor microenvironment (TME). Melanoma-derived EVs have been implicated in immune suppression and escape, promoting tumor progression. In the context of cancer patients, EVs are usually isolated from biofluids such as serum, urine, and saliva. Nonetheless, this approach neglects the fact that biofluid-derived EVs reflect not only the tumor, but also include contributions from different organs and cell types. For that, isolating EVs from tissue samples allows for studying different cell populations resident at the tumor site, such as tumor-infiltrating lymphocytes and their secreted EVs, which play a central anti-tumor role. Herein, we outline the first instance of a method for EV isolation from frozen tissue samples at high purity and sensitivity that can be easily reproduced without the need for complicated isolation methods. Our method of processing the tissue not only circumvents the need for hard-to-acquire freshly isolated tissue samples, but also preserves EV surface proteins which allows for multiplex surface markers profiling. Tissue-derived EVs provide insight into the physiological role of EVs enrichment at tumor sites, which can be overlooked when studying circulating EVs coming from different sources. Tissue-derived EVs could be further characterized in terms of their genomics and proteomics to identify possible mechanisms for regulating the TME. Additionally, identified markers could be correlated to overall patient survival and disease progression for prognostic purposes.

Ceruloplasmin is associated with the infiltration of immune cells and acts as a prognostic biomarker in patients suffering from glioma

“…The cytokines present within the peritumoral environment are involved in the overall tumor progression process. They can not only cause immunosuppression of the tumor and evade the immune surveillance, but also promote angiogenesis and enhance the growth and invasiveness of tumor cells ( Al Hrout et al, 2023 ). Therefore, a full understanding of the role of relevant cytokines in the TIME of glioma may provide an important theory for immunotherapy of glioma.…”

Cancer cell invasion alters the protein profile of extracellular vesicles

“…In contrast, three‐dimensional (3D) cell culture models provide a more accurate representation of tumour characteristics, allowing cancer cells to acquire similar morphology, growth and differentiation patterns as those detected in tumours (Duval et al., 2019 ). It is therefore no surprise that multiple studies have shown substantial differences in the secretion and cargo components of EVs between 2D and 3D cancer cell cultures (Al Hrout et al., 2023 ; Eguchi et al., 2018 ; Giusti et al., 2022 ; Kyykallio et al., 2022 ; Martins et al., 2023 ; Millan et al., 2022 ; Rocha et al., 2019 ; Szvicsek et al., 2019 ; Thippabhotla et al., 2019 ; Yang et al., 2020 ). These studies employed synthetic hydrogels and scaffolds, as well as extracellular matrix (ECM)‐based 3D cultures, but it remains to be shown whether EV secretion and characteristics change during tumour development and invasive transition.…”