Exosomes from CIITA-transfected CT26 cells enhance anti- tumor effects

Anticancer Therapy Targeting Cancer-Derived Extracellular Vesicles

Extracellular vesicles (EVs) are natural lipid nanoparticles secreted by most types of cells. In malignant cancer, EVs derived from cancer cells contribute to its progression and metastasis by facilitating tumor growth and invasion, interfering with anticancer immunity, and establishing premetastasis niches in distant organs. In recent years, multiple strategies targeting cancer-derived EVs have been proposed to improve cancer patient outcomes, including inhibiting EV generation, disrupting EVs during trafficking, and blocking EV uptake by recipient cells. Developments in EV engineering also show promising results in harnessing cancer-derived EVs as anticancer agents. Here, we summarize the current understanding of the origin and functions of cancer-derived EVs and review the recent progress in anticancer therapy targeting these EVs.

Surface-Engineered Extracellular Vesicles in Cancer Immunotherapy

Extracellular vesicles (EVs) are lipid bilayer-enclosed bodies secreted by all cell types. EVs carry bioactive materials, such as proteins, lipids, metabolites, and nucleic acids, to communicate and elicit functional alterations and phenotypic changes in the counterpart stromal cells. In cancer, cells secrete EVs to shape a tumor-promoting niche. Tumor-secreted EVs mediate communications with immune cells that determine the fate of anti-tumor therapeutic effectiveness. Surface engineering of EVs has emerged as a promising tool for the modulation of tumor microenvironments for cancer immunotherapy. Modification of EVs' surface with various molecules, such as antibodies, peptides, and proteins, can enhance their targeting specificity, immunogenicity, biodistribution, and pharmacokinetics. The diverse approaches sought for engineering EV surfaces can be categorized as physical, chemical, and genetic engineering strategies. The choice of method depends on the specific application and desired outcome. Each has its advantages and disadvantages. This review lends a bird's-eye view of the recent progress in these approaches with respect to their rational implications in the immunomodulation of tumor microenvironments (TME) from pro-tumorigenic to anti-tumorigenic ones. The strategies for modulating TME using targeted EVs, their advantages, current limitations, and future directions are discussed.

Engineered tumor cell-derived vaccines against cancer: The art of combating poison with poison

Tumor vaccination is a promising approach for tumor immunotherapy because it presents high specificity and few side effects. However, tumor vaccines that contain only a single tumor antigen can allow immune system evasion by tumor variants. Tumor antigens are complex and heterogeneous, and identifying a single antigen that is uniformly expressed by tumor cells is challenging. Whole tumor cells can produce comprehensive antigens that trigger extensive tumor-specific immune responses. Therefore, tumor cells are an ideal source of antigens for tumor vaccines. A better understanding of tumor cell-derived vaccines and their characteristics, along with the development of new technologies for antigen delivery, can help improve vaccine design. In this review, we summarize the recent advances in tumor cell-derived vaccines in cancer immunotherapy and highlight the different types of engineered approaches, mechanisms, administration methods, and future perspectives. We discuss tumor cell-derived vaccines, including whole tumor cell components, extracellular vesicles, and cell membrane-encapsulated nanoparticles. Tumor cell-derived vaccines contain multiple tumor antigens and can induce extensive and potent tumor immune responses. However, they should be engineered to overcome limitations such as insufficient immunogenicity and weak targeting. The genetic and chemical engineering of tumor cell-derived vaccines can greatly enhance their targeting, intelligence, and functionality, thereby realizing stronger tumor immunotherapy effects. Further advances in materials science, biomedicine, and oncology can facilitate the clinical translation of tumor cell-derived vaccines.

Development of Extracellular Vesicle Therapeutics: Challenges, Considerations, and Opportunities

Extracellular vesicles (EVs) hold great promise as therapeutic modalities due to their endogenous characteristics, however, further bioengineering refinement is required to address clinical and commercial limitations. Clinical applications of EV-based therapeutics are being trialed in immunomodulation, tissue regeneration and recovery, and as delivery vectors for combination therapies. Native/biological EVs possess diverse endogenous properties that offer stability and facilitate crossing of biological barriers for delivery of molecular cargo to cells, acting as a form of intercellular communication to regulate function and phenotype. Moreover, EVs are important components of paracrine signaling in stem/progenitor cell-based therapies, are employed as standalone therapies, and can be used as a drug delivery system. Despite remarkable utility of native/biological EVs, they can be improved using bio/engineering approaches to further therapeutic potential. EVs can be engineered to harbor specific pharmaceutical content, enhance their stability, and modify surface epitopes for improved tropism and targeting to cells and tissues in vivo. Limitations currently challenging the full realization of their therapeutic utility include scalability and standardization of generation, molecular characterization for design and regulation, therapeutic potency assessment, and targeted delivery. The fields' utilization of advanced technologies (imaging, quantitative analyses, multi-omics, labeling/live-cell reporters), and utility of biocompatible natural sources for producing EVs (plants, bacteria, milk) will play an important role in overcoming these limitations. Advancements in EV engineering methodologies and design will facilitate the development of EV-based therapeutics, revolutionizing the current pharmaceutical landscape.

Extracellular vesicles as a drug delivery system: A systematic review of preclinical studies

During the past decades, extracellular vesicles (EVs) have emerged as an attractive drug delivery system. Here, we assess their pre-clinical applications, in the form of a systematic review. For each study published in the past decade, disease models, animal species, EV donor cell types, active pharmaceutical ingredients (APIs), EV surface modifications, API loading methods, EV size and charge, estimation of EV purity, presence of biodistribution studies and administration routes were quantitatively analyzed in a defined and reproducible way. We have interpreted the trends we observe over the past decade, to define the niches where to apply EVs for drug delivery in the future and to provide a basis for regulatory guidelines.

Potential theranostics of circulating tumor cells and tumor-derived exosomes application in colorectal cancer

Background

At the present time, colorectal cancer (CRC) is still known as a disease with a high mortality rate. Theranostics are flawless scenarios that link diagnosis with therapy, including precision medicine as a critical platform that relies on the development of biomarkers particularly “liquid biopsy”. Circulating tumor cells (CTCs) and tumor-derived exosomes (TDEs) in a liquid biopsy approach are of substantial importance in comparison with traditional ones, which cannot generally be performed to determine the dynamics of the tumor due to its wide restriction of range. Thus, recent attempts has shifted towards minimally noninvasive methods.

Main text

CTCs and TDEs, as significant signals emitted from the tumor microenvironment, which are also detectable in the blood, prove themselves to be promising novel biomarkers for cancer diagnosis, prognosis, and treatment response prediction. The therapeutic potential of them is still limited, and studies are at its infancy. One of the major challenges for the implementation of CTCs and TDEs which are new trends in translational medicine is the development of isolation and characterization; a standardizable approach. This review highlights and discusses the current challenges to find the bio fluids application in CRC early detection and clinical management.

Conclusion

Taken together, CTCs and TDEs as silent drivers of metastasis can serve in the management of cancer patient treatment and it is of the upmost importance to expand our insight into this subject. However, due to the limited data available from clinical trials, further validations are required before addressing their putative application in oncology.

Tumor-derived exosomes: the next generation of promising cell-free vaccines in cancer immunotherapy

Identification of immunogenic tumor antigens that are efficiently processed and delivered by dendritic cells to prime the immune system and to induce an appropriate immune response is a research hotspot in the field of cancer vaccine development. High biosafety is an additional demand. Tumor-derived exosomes (TEXs) are nanosized lipid bilayer encapsulated vesicles that shuttle bioactive information to the tumor microenvironment facilitating tumor progression. However, accumulating evidence points toward the capacity of TEXs to efficiently stimulate immune responses against tumors provided they are appropriately administered. After briefly describing the function of exosomes in cancer biology and their communication with immune cells, we summarize in this review in vitro and preclinical studies eliciting the potency of TEXs in inducing effective anti-tumor responses and recently modified strategies further improving TEX-vaccination efficacy. We interpret the available data as TEXs becoming a lead in cancer vaccination based on tumor antigen-selective high immunogenicity.

Link between CIITA rs3087456 polymorphism and the risk of laryngeal squamous cell carcinoma in a Chinese population

The class II trans-activator (CIITA) is the master regulator of the major histocompatibility complex (MHC) gene expression. CIITA mutations have been previously associated with several kinds of tumors, while the role of CIITA polymorphisms (rs3087456) in laryngeal squamous cell carcinoma (LSCC) is little known. We evaluate the link between CIITA polymorphisms and the existence of LSCC in patients. This study was conducted with 200 Chinese Han patients (LSCC) and 200 healthy control subjects. The association of CIITA genetic polymorphism rs3087456 with the risk of LSCC was assessed through pyrosequencing. The CIITA expression in LSCC tumor tissue and adjacent normal tissue was detected by immunohistochemistry (IHC) staining. The relationship between the genotype of rs3087456 in controls and in clinical pathology features in LSCC were analyzed, and in-silico analysis was also used for the CIITA gene. The in-silico analysis results showed that the CIITA gene is closely related to genes such as RFX5 and RFXAP. The IHC results showed that CIITA was highly expressed in LSCC tumor tissues, compared with the corresponding adjacent normal tissues. The AG, AG + AA, and A genotypes of rs3087456 of CIITA gene notably increased the risk of LSCC compared to the controls. Our study suggests that CIITA polymorphism (rs3087456) is associated with a higher risk of developing LSCC in a Chinese cohort.

TGF-β1-silenced leukemia cell-derived exosomes target dendritic cells to induce potent anti-leukemic immunity in a mouse model

Tumor-derived exosomes (TEX) can induce a specific antitumor immune response and have been developed as a promising tumor vaccine. Despite promising preclinical data, TEX exhibit relatively low efficacy and limited clinical benefit in clinical trials. In the present study, we investigated whether exosomes from the TGF-β1 silenced L1210 cells (LEXTGF-β1si) can enhance the efficacy of DC-based vaccines. We silenced TGF-β1 in L1210 cells with a lentiviral shRNA vector and prepared the LEXTGF-β1si. It was shown that LEXTGF-β1si can significantly decrease TGF-β1 expression of dendritic cells (DC) and effectively promote their maturation and immune function. In addition, DC pulsed with LEXTGF-β1si (DCLEX-TGF-β1si) more effectively promoted CD4+ T cell proliferation in vitro and Th1 cytokine secretion and induced tumor-specific CTL response. This response was higher in potency compared to that noted by the other two formulations. Moreover, DCLEX-TGF-β1si inhibited tumor growth more efficiently than other formulations did as the preventive or therapeutic tumor vaccine. Accordingly, these findings revealed that DCLEX-TGF-β1si induced a more potent antigen-specific anti-leukemic immunity than DC pulsed with exosomes from non-manipulated L1210 cells. This indicated that the targeting of DC by LEXTGF-β1si may be used as a promising approach for leukemia immunotherapy.

Development of potent class II transactivator gene delivery systems capable of inducing de novo MHC II expression in human cells, in vitro and ex vivo

Class II transactivator (CIITA) induces transcription of major histocompatibility complex (MHC) II genes and can potentially be used to improve genetic immunotherapies by converting non-immune cells into cells capable of presenting antigens to CD4⁺ T cells. However, CIITA expression is tightly controlled and it remains unclear whether distinct non-immune cells differ in this transactivator regulation. Here we describe the development of gene delivery systems capable of promoting the efficient CIITA expression in non-immune cell lines and in primary human cells of an ex vivo skin explant model. Different human cell types undergoing CIITA overexpression presented high-level de novo expression of MHC II, validating the delivery systems as suitable tools for the CIITA evaluation as a molecular adjuvant for gene therapies.

Extracellular vesicles of ETV2 transfected fibroblasts stimulate endothelial cells and improve neovascularization in a murine model of hindlimb ischemia

Ischemia are common conditions related to lack of blood supply to tissues. Depending on the ischemic sites, ischemia can cause different diseases, such as hindlimb ischemia, heart infarction and stroke. This study aims to evaluate how extracellular vesicles (EVs) derived from ETV2 transfected fibroblasts affect endothelial cell proliferation and neovascularization in a murine model of hindlimb ischemia. Human fibroblasts were isolated and cultured under standard conditions and expanded to the 3th passage before use in experiments. Human fibroblasts were transduced with a viral vector containing the ETV2 gene. Transduced cells were selected by puromycin treatment. These cells were further cultured for collection of EVs, which were isolated from culture supernatant. Following co-culture with endothelial cells, EVs were evaluated for their effect on endothelial cell proliferation and were directly injected into ischemic tissues of a murine model of hindlimb ischemia. The results showed that EVs could induce endothelial cell proliferation in vitro and improved neovascularization in a murine model of hindlimb ischemia. Our results suggest that EVs derived from ETV2-transfected fibroblasts can be promising non-cellular products for the regeneration of blood vessels.

The exosomes in tumor immunity

Exosomes are a kind of nanometric membrane vesicles and can be released by almost all kinds of cells, including cancer cells. As the important mediators in intercellular communications, exosomes mediate exchange of protein and genetic material derived from parental cells. Emerging evidences show that exosomes secreted by either host cells or cancer cells are involved in tumor initiation, growth, invasion and metastasis. Moreover, communications between immune cells and cancer cells via exosomes play dual roles in modulating tumor immunity. In this review, we focus on exosome-mediated immunosuppression via inhibition of antitumor responses elicited by immune cells (DCs, NK cells, CD4⁺ and CD8⁺ T cells, etc.) and induction of immunosuppressive or regulatory cell populations (MDSCs, Tregs and Bregs). Transfer of cytokines, microRNAs (miRNAs) and functional mRNAs by tumor-derived exosomes (TEXs) is crucial in the immune escape. Furthermore, exosomes secreted from several kinds of immune cells (DCs, CD4⁺ and CD8⁺ Tregs) also participate in immunosuppression. On the other hand, we summarize the current application of DC-derived and modified tumor-derived exosomes as tumor vaccines. The potential challenges about exosome-based vaccines for clinical application are also discussed.

Exosome-derived microRNA-29c induces apoptosis of BIU-87 cells by down regulating BCL-2 and MCL-1

BACKGROUND

Aberrant expression of the microRNA-29 family is associated with tumorigenesis and cancer progression. As transport carriers, tumor-derived exosomes are released into the extracellular space and regulate multiple functions of target cells. Thus, we assessed the possibility that exosomes could transport microRNA- 29c as a carrier and correlations between microRNA-29c and apoptosis of bladder cancer cells.

MATERIALS AND METHODS

A total of 28 cancer and adjacent tissues were examined by immunohistochemistry to detect BCL-2 and MCL-1 expression. Disease was Ta-T1 in 12 patients, T2-T4 in 16, grade 1 in 8, 2 in 8 and 3 in 12. The expression of microRNA-29c in cancer tissues was detected by quantitative reverse transcriptase PCR (QRT- PCR). An adenovirus containing microRNA-29c was used to infect the BIU-87 human bladder cancer cell line. MicroRNA-29c in exosomes was measured by QRT-PCR. After BIU-87 cells were induced by exosomes-derived microRNA-29c, QRT-PCR was used to detect the level of microRNA-29c. Apoptosis was examined by flow cytometry and BCL-2 and MCL-1 mRNA expressions were assessed by reverse transcription-polymerase chain reaction. Western blotting was used to determine the protein expression of BCL-2 and MCL-1.

RESULTS

The expressions of BCL-2 and MCL-1 protein were remarkably increased in bladder carcinoma (p<0.05), but was found mainly in the basal and suprabasal layers in adjacent tissues. The expression of microRNA-29c in cancer tissues was negatively correlated with the BCL-2 and MCL-1. The expression level of microRNA-29c in exosomes and BIU-87 cells from the experiment group was higher than that in control groups (p<0.05). Exosome-derived microRNA-29c induced apoptosis (p<0.01). Although only BCL-2 was reduced at the mRNA level, both BCL-2 and MCL-1 were reduced at the protein level.

CONCLUSIONS

Human bladder cancer cells infected by microRNA- 29c adenovirus can transport microRNA-29c via exosomes. Moreover, exosome-derived microRNA29c induces apoptosis in bladder cancer cells by down-regulating BCL-2 and MCL-1.

Immature, Semi-Mature, and Fully Mature Dendritic Cells: Toward a DC-Cancer Cells Interface That Augments Anticancer Immunity

Dendritic cells (DCs) are the sentinel antigen-presenting cells of the immune system; such that their productive interface with the dying cancer cells is crucial for proper communication of the "non-self" status of cancer cells to the adaptive immune system. Efficiency and the ultimate success of such a communication hinges upon the maturation status of the DCs, attained following their interaction with cancer cells. Immature DCs facilitate tolerance toward cancer cells (observed for many apoptotic inducers) while fully mature DCs can strongly promote anticancer immunity if they secrete the correct combinations of cytokines [observed when DCs interact with cancer cells undergoing immunogenic cell death (ICD)]. However, an intermediate population of DC maturation, called semi-mature DCs exists, which can potentiate either tolerogenicity or pro-tumorigenic responses (as happens in the case of certain chemotherapeutics and agents exerting ambivalent immune reactions). Specific combinations of DC phenotypic markers, DC-derived cytokines/chemokines, dying cancer cell-derived danger signals, and other less characterized entities (e.g., exosomes) can define the nature and evolution of the DC maturation state. In the present review, we discuss these different maturation states of DCs, how they might be attained and which anticancer agents or cell death modalities (e.g., tolerogenic cell death vs. ICD) may regulate these states.