Immunoregulatory Potential of Exosomes Derived from Cancer Stem Cells

Aptamer-Proximity Ligation Coupled with Rolling Circle Amplification Strategy for an Ultrasensitive Analysis of Tumor-Derived Extracellular Vesicles PD-L1

Tumor-derived extracellular vesicles (T-EVs) PD-L1 are an important biomarker for predicting immunotherapy response and can help us understand the mechanism of resistance to immunotherapy. However, this is due to the interference from a large proportion of nontumor-derived EVs. It is still challenging to accurately analyze T-EVs PD-L1 in complex human fluids. Herein, a simple and ultrasensitive method based on the dual-aptamer-proximity ligation assay (PLA)-guided rolling circle amplification (RCA) for the analysis of T-EVs PD-L1 was developed. First, dual aptamers with strong binding affinity were utilized for the recognition of EpCAM and PD-L1 on EVs, and then the aptamer-based PLA occurred. With the aid of the high signal amplification ability of RCA guided by the dual-aptamer-based PLA and efficient magnetic separation, the biosensor could realize highly sensitive quantification of EpCAM and PD-L1 dual-positive EVs with a low detection limit of 7.5 particles/μL. In addition, this method based on the aptamer-PLA-guided RCA was used to discriminate cancer patients from healthy donors with 100% accuracy without additional purification. Overall, this strategy might provide a practical tool for the analysis of multiple proteins on EVs, exhibiting great potential in early cancer diagnosis and treatment.

Exosomal miR-4516 derived from ovarian cancer stem cells enhanced cisplatin tolerance in ovarian cancer by inhibiting GAS7

Ovarian cancer (OC) is a devastating disease for women, with chemotherapy resistance taking the lead. Cisplatin has been the first-line therapy for OC for a long time. However, the resistance of OC to cisplatin is an important impediment to its efficacy. Mounting studies showed that ovarian cancer stem cells (OCSCs) affected chemotherapy resistance by secreting exosomes. MicroRNAs (miRNAs) play important roles in exosomes secreted by OCSCs. Here, through the analysis of GEO database (GSE107155) combined with RT-qPCR of OC-related cells/clinical tissues, it was found that hsa-miR-4516 (miR-4516) was significantly up-regulated in OCSCs. Then, OCSCs-derived exosomes were isolated and identified, and it was observed the influence of exosomes on the chemoresistance in SKOV3/cisplatin (SKOV3/DDP) cells. These results manifested that OCSCs-mediated exosomes facilitated the chemoresistance of SKOV3/DDP cells by delivering miR-4516 into them. Growth arrest-specific 7 (GAS7), a downstream target of miR-4516, was determined by bioinformatics prediction combined with molecular biological detection. Next, we up-regulated GAS7 expression and discovered that the promotion of chemoresistance in SKOV3/DDP cells by OCSCs-derived exosomes was significantly impaired. Finally, the mice tumor model of SKOV3/DDP cells was built to estimate the effect of GAS7 over-expression on OC growth. The results showed that GAS7 inhibited the chemoresistance of OC in vivo. In conclusion, our experiments suggested that OCSCs-derived exosomes enhanced OC cisplatin resistance by suppressing GAS7 through the delivery of miR-4516. This study provides a possible target for the treatment of OC DDP resistance.

The roles of lncRNAs in the development of drug resistance of oral cancers

Oral cancers are a significant global health concern, with a high incidence of treatment failure primarily due to the development of drug resistance. Long non-coding RNAs (lncRNAs) have emerged as critical regulators of gene expression, playing pivotal roles in various cellular processes, including tumor progression and response to therapy. This review explores the multifaceted roles of lncRNAs in the development of drug resistance in oral cancers. We highlight the mechanisms by which lncRNAs modulate drug efflux, apoptosis, epithelial-mesenchymal transition (EMT), and other pathways associated with chemoresistance. Key lncRNAs implicated in resistance to commonly used chemotherapeutic agents in oral cancers are discussed, along with their potential as therapeutic targets. Understanding the involvement of lncRNAs in drug resistance mechanisms offers promising avenues for overcoming treatment barriers and improving patient outcomes. This review underscores the need for further research to elucidate the precise roles of lncRNAs in oral cancer resistance and their translation into clinical interventions.

Therapeutic combinations of exosomes alongside cancer stem cells (CSCs) and of CSC-derived exosomes (CSCEXs) in cancer therapy

Exosomes which are membrane vesicles released by cells have gained significant interest in the field of cancer therapy as a novel means of intercellular communication. Their role in immune activation and their pathophysiological functions in cancer therapy have been recognized. Exosomes carry diverse bioactive components including proteins, mRNA, microRNAs, and bioactive lipids. These molecules have therapeutic potential in promoting tissue regeneration, supporting stem cell activity, preventing cell death, modulating immune responses, and promoting the growth of new blood vessels. However, the precise roles of exosomes derived from mesenchymal stem cells (MSCs) in the treatment of various cancers are still not fully understood. Consequently, cancer stem cells (CSCs) can self-renew and differentiate into various cell types. Understanding the mechanisms that sustain their persistence is crucial for developing effective therapies. Exosomes have recently gained interest as vehicles for intercellular communication between CSCs and non-CSCs, influencing cancer progression and the microenvironment. Research is ongoing on the utilization of exosomes derived from cancer stem cells (CSC-Exosome) for cancer treatment. The composition of extracellular vesicles is influenced by the specific type and condition of the cells from which they are secreted. Circulating exosomes contain stable RNA molecules such as mRNAs, microRNAs, and long non-coding RNAs (lncRNAs). In this review, we will explore the significance of exosomes and their diverse cellular combinations in the context of cancer therapy.

Exosomes-based immunotherapy for cancer: Effective components in the naïve and engineered forms

Today, cancer treatment is one of the main challenges for researchers. The main cause of tumor cell formation is mutations that lead to uncontrolled proliferation and inhibition of apoptosis in malignant cells. Tumor cells also create a microenvironment that can suppress the immune system cells' responses through various methods, including producing soluble factors and cell-to-cell communication. After being produced from tumor cells, exosomes can also affect the functions of other cells in this microenvironment. Various studies have shown that exosomes from different sources, including tumor cells and immune cells, can be used to treat cancers due to their characteristics. Since tumor cells are rich sources of various types of tumor peptides, they can induce anti-tumor responses. Immune cells also produce exosomes that mimic the functions of their cells of origin, such that exosomes derived from NK cells and CTLs can directly lead to their apoptosis after merging with tumor cells. However, many researchers have pointed out that naïve exosomes have a limited therapeutic function, and their therapeutic potential can be increased by manipulating and engineering them. There are various methods to modify exosomes and improve their therapeutic potential. In general, these methods are divided into two parts, which include changing the cell of origin of the exosome and encapsulating the exosome to carry different drugs. In this review, we will discuss the studies on the therapeutic use of naive and engineered exosomes and provide an update on new studies in this field.

Cancer Stem Cell Derived Extracellular Vesicles with Self-Functionalized 3D Nanosensor for Real-Time Cancer Diagnosis: Eliminating the Roadblocks in Liquid Biopsy

Liquid biopsy for determining the presence of cancer and the underlying tissue of origin is crucial to overcome the limitations of existing tissue biopsy and imaging-based techniques by capturing critical information from the dynamic tumor heterogeneity. A newly emerging liquid biopsy with extracellular vesicles (EVs) is gaining momentum, but its clinical relevance is in question due to the biological and technical challenges posed by existing technologies. The biological barriers of existing technologies include the inability to generate fundamental details of molecular structure, chemical composition as well as functional variations in EVs by gathering simultaneous information on multiple intra-EV molecules, unavailability of holistic qualitative analysis, in addition to the inability to identify tissue of origin. Technological barriers include reliance on EV isolation with a few labeled biomarkers, resulting in the inability to generate comprehensive information on the disease. A more favorable approach would be to generate holistic information on the disease without the use of labels. Such a marker-free diagnosis is impossible with the existing liquid biopsy due to the unavailability clinically validated cancer stem cells (CSC)-specific markers and dependence of existing technologies on EV isolation, undermining the clinical relevance of EV-based liquid biopsy. Here, CSC EVs were employed as an independent liquid biopsy modality. We hypothesize that tracking the signals of CSCs in peripheral blood with CSC EVs will provide a reliable solution for accurate cancer diagnosis, as CSC are the originators of tumor contributing to tumor heterogeneity. We report nanoengineered 3D sensors of extremely small nano-scaled probes self-functionalized for SERS, enabling integrative molecular and functional profiling of otherwise undetectable CSC EVs. A substantially enhanced SERS and ultralow limit of detection (10 EVs per 10 μL) were achieved. This was attributed to the efficient probe-EV interaction due to the 3D networks of nanoprobes, ensuring simultaneous detection of multiple EV signals. We experimentally demonstrate the crucial role of CSC EVs in cancer diagnosis. We then completed a pilot validation of this modality for cancer detection as well as for identification of the tissue of origin. An artificial neural network distinguished cancer from noncancer with 100% sensitivity and 100% specificity for three hard to detect cancers (breast, lung, and colorectal cancer). Binary classification to distinguish one tissue of origin against all other achieved 100% accuracy, while simultaneous identification of all three tissues of origin with multiclass classification achieved up to 79% accuracy. This noninvasive tool may complement existing cancer diagnostics, treatment monitoring as well as longitudinal disease monitoring by validation with a large cohort of clinical samples.

Exosomes: Potential Biomarkers and Functions in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC), originating from the mucosal epithelial cells of the oral cavity, pharynx, and larynx, is a lethal malignancy of the head and neck. Patients with advanced and recurrent HNSCC have poor outcomes due to limited therapeutic options. Exosomes have active roles in the pathophysiology of tumors and are suggested as a potential therapeutic target of HNSCC. Exosomes in HNSCC have been intensively studied for disease activity, tumor staging, immunosuppression, and therapeutic monitoring. In this review, the biological mechanisms and the recent clinical application of exosomes are highlighted to reveal the potential of exosomes as biomarkers and therapeutic targets for HNSCC.

Extracellular Vesicle Measurements with Nanoparticle Tracking Analysis: A Different Appreciation of Up and Down Secretion

As is the case with most eucaryotic cells, cancer cells are able to secrete extracellular vesicles (EVs) as a communication means towards their environment and surrounding cells. EVs are represented by microvesicles and smaller vesicles called exosomes, which are known for their involvement in cancer aggressiveness. The release of such EVs requires the intervention of trafficking-associated proteins, mostly represented by the RAB-GTPases family. In particular, RAB27A is known for its role in addressing EVs-to-be secreted towards the the plasma membrane. In this study, shRNAs targeting RAB27A were used in colorectal (CRC) and glioblastoma (GB) cell lines in order to alter EVs secretion. To study and monitor EVs secretion in cell lines’ supernatants, nanoparticle tracking analysis (NTA) was used through the NanoSight NS300 device. Since it appeared that NanoSight failed to detect the decrease in the EVs secretion, we performed another approach to drop EVs secretion (RAB27A-siRNA, indomethacin, Nexihnib20). Similar results were obtained i.e., no variation in EVs concentration. Conversely, NTA allowed us to monitor EVs up-secretion following rotenone treatment or hypoxia conditions. Therefore, our data seemed to point out the insufficiency of using only this technique for the assessment of EVs secretion decrease.

Exosomal circCARM1 from spheroids reprograms cell metabolism by regulating PFKFB2 in breast cancer

Cancer stem cells (CSC) are the major obstacle for cancer therapy in clinic. Exosomes are one type of vesicles that containing circular RNA (circRNAs) involved in cell-cell communication. However, the roles of breast CSC (BCSC) exosomes are still unclear, and the purpose of the study was to investigate breast cancer cell metabolism reprogramming by circRNAs from BCSC exosomes. The circRNA array was performed in the exosomes secreted from spheroids of MDA-231 cells. circCARM1 was higher in BCSC exosomes than it in the parent breast cancer cells. Further investigation demonstrated that BCSC exosomes circCARM1 played an important role in breast cancer cell glycolysis by miR-1252-5p/PFKFB2. In a conclusion, BCSC exosome-derived circCARM1 played an important role in breast cancer cell glycolysis by sponging miR-1252-5p which regulated PFKFB2 expression.

Therapeutic potentials of resveratrol in combination with radiotherapy and chemotherapy during glioblastoma treatment: a mechanistic review

Glioblastoma, WHO grade IV astrocytoma, is the most aggressive type of brain tumors. These cancerous cells have a rapid growth rate, tendency to penetrate vital brain structures, molecular heterogeneity, etc. and this cancer is associated with a poor prognosis and low survival rate. Due to the resistance of glioblastoma cells to conventional therapeutic modalities (such as radiation therapy and chemotherapy) as well as the adverse effects of these modalities, the researchers have attempted to discover an appropriate alternative or adjuvant treatment for glioblastoma. Resveratrol, as an herbal and natural polyphenolic compound, has anti-tumoral property and has shown to be effective in GBM treatment. Resveratrol exerts its anti-tumoral effect through various mechanisms such as regulation of cell cycle progression and cell proliferation, autophagy, oxidant system, apoptosis pathways, and so on. Resveratrol in combination with radiation therapy and chemotherapy has also been used. In the present study, we summarized the current findings on therapeutic potentials of resveratrol in glioblastoma radiotherapy and chemotherapy.

Emerging role of tumor microenvironment derived exosomes in therapeutic resistance and metastasis through epithelial-to-mesenchymal transition

The tumor microenvironment (TME) constitutes multiple cell types including cancerous and non-cancerous cells. The intercellular communication between these cells through TME derived exosomes may either enhance or suppress the tumorigenic processes. The tumor-derived exosomes could convert an anti-tumor environment into a pro-tumor environment by inducing the differentiation of stromal cells into tumor-associated cells. The exosomes from tumor-associated stromal cells reciprocally trigger epithelial-to-mesenchymal transition (EMT) in tumor cells, which impose therapeutic resistance and metastasis. It is well known that these exosomes contain the signals of EMT, but how these signals execute chemoresistance and metastasis in tumors remains elusive. Understanding the significance and molecular signatures of exosomes transmitting EMT signals would aid in developing appropriate methods of inhibiting them. In this review, we focus on molecular signatures of exosomes that shuttle between cancer cells and their stromal populations in TME to explicate their impact on therapeutic resistance and metastasis through EMT. Especially Wnt signaling is found to be involved in multiple ways of exosomal transport and hence we decipher the biomolecules of Wnt signaling trafficked through exosomes and their potential in serving as therapeutic targets.

Exosomes and Cancer Stem Cells in Cancer Immunity: Current Reports and Future Directions

Cancer stem cells (CSCs), which have the capacity to self-renew and differentiate into various types of cells, are notorious for their roles in tumor initiation, metastasis, and therapy resistance. Thus, underlying mechanisms for their survival provide key insights into developing effective therapeutic strategies. A more recent focus has been on exosomes that play a role in transmitting information between CSCs and non-CSCs, resulting in activating CSCs for cancer progression and modulating their surrounding microenvironment. The field of CSC-derived exosomes (CSCEXs) for different types of cancer is still under exploration. A deeper understanding and further investigation into CSCEXs’ roles in tumorigenicity and the identification of novel exosomal components are necessary for engineering exosomes for the treatment of cancer. Here, we review the features of CSCEXs, including surface markers, cargo, and biological or physiological functions. Further, reports on the immunomodulatory effects of CSCEXs are summarized, and exosome engineering for CSC-targeting is also discussed.

Differences and similarities between cancer and somatic stem cells: therapeutic implications

Over the last decades, the cancer survival rate has increased due to personalized therapies, the discovery of targeted therapeutics and novel biological agents, and the application of palliative treatments. Despite these advances, tumor resistance to chemotherapy and radiation and rapid progression to metastatic disease are still seen in many patients. Evidence has shown that cancer stem cells (CSCs), a sub-population of cells that share many common characteristics with somatic stem cells (SSCs), contribute to this therapeutic failure. The most critical properties of CSCs are their self-renewal ability and their capacity for differentiation into heterogeneous populations of cancer cells. Although CSCs only constitute a low percentage of the total tumor mass, these cells can regrow the tumor mass on their own. Initially identified in leukemia, CSCs have subsequently been found in cancers of the breast, the colon, the pancreas, and the brain. Common genetic and phenotypic features found in both SSCs and CSCs, including upregulated signaling pathways such as Notch, Wnt, Hedgehog, and TGF-β. These pathways play fundamental roles in the development as well as in the control of cell survival and cell fate and are relevant to therapeutic targeting of CSCs. The differences in the expression of membrane proteins and exosome-delivered microRNAs between SSCs and CSCs are also important to specifically target the stem cells of the cancer. Further research efforts should be directed toward elucidation of the fundamental differences between SSCs and CSCs to improve existing therapies and generate new clinically relevant cancer treatments.

Exosomal miR-548c-5p Regulates Colorectal Cancer Cell Growth and Invasion Through HIF1A/CDC42 Axis

Background

Mounting evidence has implicated that exosomes-delivered noncoding RNAs are key regulators in carcinogenesis. The effect of miR-548c-5p has been elucidated in some cancers. However, the role of exosomal miR-548c-5p in colorectal cancer (CRC) is not fully understood. We aim to explore the function and mechanism of exosome-delivered miR-548c-5p in CRC. The altering effect of exosome-derived miR-548c-5p on the prognosis of CRC patients is also investigated by estimating overall survival and disease-free survival.

Materials and Methods

The expression of miR-548c-5p in exosomes is determined by real-time PCR. The proliferation and invasion of CRC cells are estimated by MTT, transwell assay and scratch test. The targeted gene of miR-548c-5p is investigated by luciferase reporter assay, real-time PCR, Western blot and chromosome immunoprecipitation (CHIP) assay. CRC cells are transplanted subcutaneously in BALB/c nude mice to estimate their growth in vivo.

Results

MiR-548c-5p derived from CRC cell exosomes inhibits the proliferation and invasion of CRC cells in vitro. Exosomal miR-548c-5p can also prevent from colorectal carcinogenesis in nude mice in vivo. HIF1A is documented to be a target of miR-548c-5p, and HIF1A can targetedly regulate CDC42 in CRC cells. Exosomal miR-548c-5p affects CRC cell growth, migration and invasion via miR-548c-5p/HIF1A/CDC42 axis. In addition, exosomal miR-548c-5p can be a predictive factor for CRC prognosis.

Conclusion

Our study has suggested that exosomal miR-548c-5p can regulate CRC through HIF1A/CDC42 axis, which helps to understand CRC pathogenesis more clearly and identify novel therapeutic strategies for CRC patients.

Purinergic Signaling in the Hallmarks of Cancer

Cancer is a complex expression of an altered state of cellular differentiation associated with severe clinical repercussions. The effort to characterize this pathological entity to understand its underlying mechanisms and visualize potential therapeutic strategies has been constant. In this context, some cellular (enhanced duplication, immunological evasion), metabolic (aerobic glycolysis, failure in DNA repair mechanisms) and physiological (circadian disruption) parameters have been considered as cancer hallmarks. The list of these hallmarks has been growing in recent years, since it has been demonstrated that various physiological systems misfunction in well-characterized ways upon the onset and establishment of the carcinogenic process. This is the case with the purinergic system, a signaling pathway formed by nucleotides/nucleosides (mainly adenosine triphosphate (ATP), adenosine (ADO) and uridine triphosphate (UTP)) with their corresponding membrane receptors and defined transduction mechanisms. The dynamic equilibrium between ATP and ADO, which is accomplished by the presence and regulation of a set of ectonucleotidases, defines the pro-carcinogenic or anti-cancerous final outline in tumors and cancer cell lines. So far, the purinergic system has been recognized as a potential therapeutic target in cancerous and tumoral ailments.

Aptamer-Cholesterol-Mediated Proximity Ligation Assay for Accurate Identification of Exosomes

Accurate identification of exosomes plays an essential role in facilitating disease diagnosis and therapies. Herein, we proposed an Aptamer-cholesterol-mediated Proximity Ligation Assay (AcmPLA) for accurate identification of exosomes in a dual-probe strategy, one aptamer probe for recognition of exosomal innate surface protein CD63 and another cholesterol probe for biolipid layer targeting. By integrating a proximity ligation of probes bound with exosomal biomarkers for specific recognition and a rolling circle amplification (RCA) strategy for signal amplification, we have successfully developed an exosomes-surface approach that can perform "AND" logic analysis of dual biomarkers, which not only could be used for exosomes quantification, but also for exosomes tracing. Besides RCA-initiated signal amplification, CD9 antibody-labeled magnetic beads were used to capture exosomes for isolation and secondary signal enrichment. Our approach can achieve specific exosomes isolation and accurate identification and thus could be exploited for broad applications in biological science, biomedical engineering, and personalized medicine.