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Exosomes are a subgroup of extracellular vesicles generated by distinct cells. Tumor-derived extracellular vesicles convey immunological checkpoint molecules. TEXs as critical mediators in tumor development, metastasis, and immune escape have recently become the focus of scientific research. Exosomes are involved in the regulation of the immune system. Exosomes interact with target cells in the tumor microenvironment, changing their function based on the cargo they contain. Exosomal immune checkpoints might be exploited to track tumor immune evasion, treatment response, and patient prognosis while enhancing tumor cell proliferation and spread. This review focuses on tumor-derived exosomes, their immunosuppressive effects in mice models, and their role in cancer immunotherapy. Exosomes are being studied as possible cancer vaccines, with numerous uses in tumor immunotherapy. Exosomes can carry chemotherapeutics, siRNA, and monoclonal antibodies. Exosomes produced by macrophages might be used to treat cancer. These and other clinical consequences provide new doors for cancer treatment.

The outbreak of coronavirus disease 2019 (COVID-19) has posed a serious threat to public health. There is an urgent need for discovery methods for the prevention and treatment of COVID-19 infection. Understanding immunogenicity together with immune responses are expected to provide further information about this virus. We hope that this narrative review article may create new insights for researchers to take great strides toward designing vaccines and novel therapies in the near future. The functional properties of the immune system in COVID-19 infection is not exactly clarified yet. This is compounded by the many gaps in our understanding of the SARS-CoV-2 immunogenicity properties. Possible immune responses according to current literature are discussed as the first line of defense and acquired immunity. Here, we focus on proposed modern preventive immunotherapy methods in COVID-19 infection.

The deregulation of microRNAs (miRs) has been identified in tumor development. Indeed, the restoration of tumor-suppressive miRs has been associated with inhibited tumor development in various cancers. Herein, we aimed to evaluate the impact of combined miR-383-5p restoration, as a tumor-suppressive miR, with taxol therapy in suppressing MDA-MB-231 breast cancer development. MDA-MB-231 cell line was restored with miR-383-5p and treated with paclitaxel both in combined and separate manners. The MTT experiment was carried out to measure the cytotoxicity of the therapeutic approaches on the tumoral cells. Besides, flow cytometry was conducted to assess apoptosis and cell cycle status following the treatments. Furthermore, the expression levels of critical factors contributed to tumor proliferation, migration, apoptosis were investigated via the qRT-PCR and western blotting techniques. The outcomes pointed out that the miR-383-5p might substantially enhance the chemosensitivity of MDA-MB-231 to taxol. Besides, miR-383-5p restoration and the combined therapy of miR-383-5p restoration with paclitaxel could remarkably increase apoptosis, decrease cell viability, arrest the cell cycle, inhibit clonogenicity, suppress tumor migration, suppress the PI3K/Akt signaling pathway, and down-regulate PD-L1 expression of BC cells. The restoration of miR-383-5p can enhance the chemosensitivity of MDA-MB-231 cells to taxol. Despite the anti-tumoral effects of miR-383-5p restoration on MDA-MB-231 breast cancer development, the combined therapy of miR-383-5p restoration with paclitaxel can be more effective in repressing MDA-MB-231 breast cancer development.

Cancer is a gravely important health issue all over the world and has been spreading fast. In recent years immune checkpoint treatment options have been used extensively as a primary line of treatment for different cancer types. PD-1 and its ligand, PD-L1, are members of the immune-checkpoints superfamily. Anti-PD-L1 and anti-PD-1 antibodies have shown efficacy against different cancer types, but fewer than 30% of patients have shown robust therapeutic responses and, therefore, it is hypothesized that exosomal PD-L1 is the mechanism to blame for failure in primary immune checkpoint therapy. The identical membrane topology of exosomal PD-L1 with tumor cell membrane-type provides the possibility to mimic immunosuppressive effects of tumor cell membrane PD-L1. In this review, it is discussed whether exosomal PD-L1 binds to antibodies and hence resistance to immunotherapy will be developed, and targeting exosome biogenesis inhibition can provide a new strategy to overcome tumor resistance to anti-PD-L1 therapy. Diagnostic and prognostic values of exosomal PD-L1 in different cancer types are discussed. Multiple clinical studies conclude that the level of tumor-derived exosomes (TEXs) as a biomarker for diagnosis could distinguish cancer patients from healthy controls. Elevated exosomal PD-L1 levels may be predictive of advanced disease stages, cancer metastasis, lower response to anti-PD-1/PD-L1 therapy, lower overall survival rates, and poor tumor prognosis. These novel findings of TEXs serve as promising therapeutic targets for early diagnosis and prevention of cancer progression.

The deregulation of microRNAs (miRs) has been identified in tumor development. Indeed, the restoration of tumor-suppressive miRs has been associated with inhibited tumor development in various cancers. Herein, we aimed to evaluate the impact of combined miR-383-5p restoration, as a tumor-suppressive miR, with taxol therapy in suppressing MDA-MB-231 breast cancer development. MDA-MB-231 cell line was restored with miR-383-5p and treated with paclitaxel both in combined and separate manners. The MTT experiment was carried out to measure the cytotoxicity of the therapeutic approaches on the tumoral cells. Besides, flow cytometry was conducted to assess apoptosis and cell cycle status following the treatments. Furthermore, the expression levels of critical factors contributed to tumor proliferation, migration, apoptosis were investigated via the qRT-PCR and western blotting techniques. The outcomes pointed out that the miR-383-5p might substantially enhance the chemosensitivity of MDA-MB-231 to taxol. Besides, miR-383-5p restoration and the combined therapy of miR-383-5p restoration with paclitaxel could remarkably increase apoptosis, decrease cell viability, arrest the cell cycle, inhibit clonogenicity, suppress tumor migration, suppress the PI3K/Akt signaling pathway, and down-regulate PD-L1 expression of BC cells. The restoration of miR-383-5p can enhance the chemosensitivity of MDA-MB-231 cells to taxol. Despite the anti-tumoral effects of miR-383-5p restoration on MDA-MB-231 breast cancer development, the combined therapy of miR-383-5p restoration with paclitaxel can be more effective in repressing MDA-MB-231 breast cancer development.

Preclinical studies have indicated that T-cell immunoglobulin and ITIM domain (TIGIT) can substantially attenuate anti-tumoral immune responses. Although multiple clinical studies have evaluated the significance of TIGIT in patients with solid cancers, their results remain inconclusive. Thus, we conducted the current systematic review and meta-analysis based on the preferred reporting items for systematic reviews and meta-analyses (PRISMA) to determine its significance in patients with solid cancers. We systematically searched the Web of Science, Embase, PubMed, and Scopus databases to obtain peer-reviewed studies published before September 20, 2020. Our results have shown that increased TIGIT expression has been significantly associated with inferior overall survival (OS) (HR = 1.42, 95% CI: 1.11–1.82, and p-value = 0.01). Besides, the level of tumor-infiltrating TIGIT+CD8+ T-cells have been remarkably associated inferior OS and relapse-free survival (RFS) of affected patients (HR = 2.17, 95% CI: 1.43–3.29, and p-value < 0.001, and HR = 1.89, 95% CI: 1.36–2.63, and p-value < 0.001, respectively). Also, there is a strong positive association between TIGIT expression with programmed cell death-1 (PD-1) expression in these patients (OR = 1.71, 95% CI: 1.10–2.68, and p-value = 0.02). In summary, increased TIGIT expression and increased infiltration of TIGIT+CD8+ T-cells can substantially worsen the prognosis of patients with solid cancers. Besides, concerning the observed strong association between TIGIT and PD-1, ongoing clinical trials, and promising preclinical results, PD-1/TIGIT dual blockade can potentially help overcome the immune-resistance state seen following monotherapy with a single immune checkpoint inhibitor in patients with solid cancers.

The programmed death-ligand 1 (PD-L1)/programmed cell death protein 1 (PD-1) is a well-established inhibitory immune checkpoint axis in triple-negative breast cancer (TNBC). Growing evidence indicates that tumoral PD-L1 can lead to TNBC development. Although conventional immune checkpoint inhibitors have improved TNBC patients’ prognosis, their effect is mainly focused on improving anti-tumoral immune responses without substantially regulating oncogenic signaling pathways in tumoral cells. Moreover, the conventional immune checkpoint inhibitors cannot impede the de novo expression of oncoproteins, like PD-L1, in tumoral cells. Accumulating evidence has indicated that the restoration of specific microRNAs (miRs) can downregulate tumoral PD-L1 and inhibit TNBC development. Since miRs can target multiple mRNAs, miR-based gene therapy can be an appealing approach to inhibit the de novo expression of oncoproteins, like PD-L1, restore anti-tumoral immune responses, and regulate various intracellular singling pathways in TNBC. Therefore, we conducted the current systematic review based on the preferred reporting items for systematic reviews and meta-analyses (PRISMA) to provide a comprehensive and unbiased synthesis of currently available evidence regarding the effect of PD-L1-inhibiting miRs restoration on TNBC development and tumor microenvironment. For this purpose, we systematically searched the Cochrane Library, Embase, Scopus, PubMed, ProQuest, Web of Science, Ovid, and IranDoc databases to obtain the relevant peer-reviewed studies published before 25 May 2021. Based on the current evidence, the restoration of miR-424-5p, miR-138-5p, miR-570-3p, miR-200c-3p, miR-383-5p, miR-34a-5p, miR-3609, miR-195-5p, and miR-497-5p can inhibit tumoral PD-L1 expression, transform immunosuppressive tumor microenvironment into the pro-inflammatory tumor microenvironment, inhibit tumor proliferation, suppress tumor migration, enhance chemosensitivity of tumoral cells, stimulate tumor apoptosis, arrest cell cycle, repress the clonogenicity of tumoral cells, and regulate various oncogenic signaling pathways in TNBC cells. Concerning the biocompatibility of biomimetic carriers and the valuable insights provided by the single-cell sequencing technologies, single-cell sequencing-guided biomimetic delivery of these PD-L1-inhibiting miRs can decrease the toxicity of traditional approaches, increase the specificity of miR-delivery, enhance the efficacy of miR delivery, and provide the affected patients with personalized cancer therapy.

Triple-negative breast cancer (TNBC) is an invasive tumor with a high incidence of distant metastasis and poor prognosis. In TNBC cells, high PD-L1 expression can induce an immunosuppressive tumor microenvironment, repressing the anti-tumoral immune responses. Although FDA-approved agents targeting the PD-1/PD-L1 axis are potent to eliminate tumoral cells, their immune-related adverse events have become worrisome. As the regulator of gene expression, siRNAs can directly target PD-L1 in breast cancer cells. The gene modification of tumoral PD-L1 can reduce our reliance on the current method of targeting the PD-L1/PD-1 axis. We initiated the study with bioinformatics analysis; the results indicated that TNBC and the MDA-MB-231 cells significantly overexpressed PD-L1 compared to other breast cancer subtypes and cell lines. Our results demonstrated that PD-L1 silencing substantially reduced PD-L1 expression at mRNA and protein levels in MDA-MB-231 cells. Moreover, our results demonstrated that PD-L1 knockdown reduced cancer cell proliferation and induced apoptosis via intrinsic and extrinsic apoptosis pathways. We observed that PD-L1 silencing effectively inhibited the migration of TNBC cells. Further investigation also displayed that silencing of PD-L1 in breast cancer cells induced T-cell cytotoxic function by upregulating the gene expression of pro-inflammatory cytokines, i.e., IL-2, IFN-γ, and TNF-α, and downregulating the gene expression of anti-inflammatory cytokines, i.e., IL-10, and TGF-β, in a co-culture system.

Over the past decade, therapeutic messenger RNAs (mRNAs) have emerged as a highly promising new class of drugs for protein replacement therapies. Due to the recent developments, the incorporation of modified nucleotides in synthetic mRNAs can lead to maximizing protein expression and reducing adverse immunogenicity. Despite these stunning improvements, mRNA therapy is limited by the need for the development of safe and efficient carriers to protect the mRNA integrity for in vivo applications. Recently, leading candidates for in vivo drug delivery vehicles are cell-derived exosomes, which have fewer immunogenic responses. In the current study, the key hurdles facing mRNA-based therapeutics, with an emphasis on recent strategies to overcoming its immunogenicity and instability, were highlighted. Then the immunogenicity and toxicity of exosomes derived from various cell sources were mentioned in detail. Finally, an overview of the recent strategies in using exosomes for mRNA delivery in the treatment of multiple diseases was stated.

Gynecologic cancers account for approximately 11% of the newly diagnosed cancers in women in the United States and for 18% globally. The presence of tumor-infiltrating lymphocytes (TILs) influences the clinical outcome of cancer patients and immune checkpoint inhibitors (ICIs), including anti programmed cell death protein-1 (anti-PD-1), anti-programmed death-ligand 1 (anti-PD-L1), and anticytotoxic T-lymphocyte antigen 4 (anti-CTLA-4), which have been approved for treating different types of malignancies. Antibodies targeting the PD-1/PD-L1 checkpoint have shown dynamic and durable tumor regressions, suggesting a rebalancing of the host–tumor interaction. There are several the US food and drug administration (FDA)-approved ICIs targeting PD-1, including pembrolizumab and nivolumab, as well as those targeting PD-L1, including avelumab, atezolizumab, and durvalumab for melanoma, renal cell cancer, colorectal cancer, head and neck cancer, cervix cancer, urothelial cancer, and lung cancer. Current pre-clinical and clinical studies assessing PD-1/PD-L1 inhibitors in several gynecologic cancers have reported significant antitumor activity. In this review, we investigate pre-clinical and clinical studies that describe the safety and efficacy of anti-PD-1/PD-L1 antibodies, with a particular focus on ongoing clinical trials, analyzing the oncological outcome and adverse effects of ICIs in gynecologic cancers.

Mesenchymal stem cells (MSCs) are multipotent stromal cells that can differentiate into a variety of cell types. They control the process of hematopoiesis by secreting regulatory cytokines and growth factors and by the expression of important cell adhesion molecules for cell-to-cell interactions. This investigation was intended to examine the effect of bone marrow (BM)-derived MSCs on the differentiation of HL-60 cells according to morphological evaluation, flow cytometry analysis, and gene expression profile.The BM-MSCs were cultured in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum (FBS). After the third passage, the BM-MSCs were irradiated at 30 Gy. To compare how the HL-60 cells differentiated in groups treated differently, HL-60 cells were cultured in RPMI-1640 and supplemented with 10% FBS. The HL-60 cells were seeded into six-well culture plates and treated with all-trans-retinoic acid (ATRA), BM-MSCs, or BM-MSCs in combination with ATRA, while one well remained as untreated HL-60 cells. The expression levels of the granulocyte subset-specific genes in the HL-60 cells were assayed by real-time polymerase chain reaction.Our results revealed that BM-MSCs support the granulocytic differentiation of the human promyelocytic leukemia cell line HL-60.Based on the results of this study, we concluded that BM-MSCs may be an effective resource in reducing or even preventing ATRA's side effects and may promote differentiation for short medication periods. Though BM-MSCs are effective resources, more complementary studies are necessary to improve this differentiation mechanism in clinical cases.Amaç: Mezankimal kök hücreler (MKH) birçok hücre tipine göre farklılaşabilen multipotent stromal hücrelerdir. Hematopoez sürecini düzenleyici sitokinler ve büyüme faktörleri salınımı ile ve hücreler arası etkileşim için önemli hücresel adezyon moleküllerinin ifadesi yoluyla kontrol ederler. Bu çalışma da kemik iliği (Kİ) kaynaklı MKH HL-60 hücrelerinin farklılaşması üzerine etkisini morfolojik değerlendirme, akım sitometri ve gen ifade analizi yöntemleriyle araştırılması amaçlanmıştır. Gereç ve Yöntemler: Kİ-MKH %10 fetal sığır serumu (FSS) içeren Dulbecco’nun modifiye Eagle ortamında kültür edildi. Üçüncü pasaj sonrası, Kİ-MKH 30 Gy ile ışınlandı. HL-60 hücrelerinin farklı şartlarda nasıl farklılaştığını karşılaştırmak için HL-60 hücreler %10 FSS eklenmiş RPMI-1640 ortamında kültür edildi. HL-60 hücreleri altı kuyucuklu plaklarda all-trans retinoik asit (ATRA), Kİ-MKH ve ATRA ile birlikte Kİ-MKH ile muamele edilirken, bir kuyucuğa sadece HL-60 hücreleri kondu. HL-60 hücrelerinde granülosit alt gruplarına özgü genlerin ifade düzeyleri gerçek zamanlı polimeraz zincir reaksiyonu ile değerlendirildi. Bulgular: Sonuçlarımız Kİ-MKH’nin insan promiyelositik lösemi hücre dizisi HL-60’ın granülositik farklılaşmasını desteklediğini gösterdi. Sonuç: Bu çalışmanın bulgularına göre, Kİ-MKH’nin ATRA yan etkilerini azaltıcı ve hatta önleyici etkili bir kaynak olduğu ve kısa ilaç kullanımı süreçlerinde farklılaşmayı uyarabileceği sonucunu çıkarttık. Kİ-MKH etkili bir kaynak olsa da, klinik olgularda bu farklılaşma mekanizmasını iyileştirmek için destekleyici ek çalışmalara ihtiyaç vardır.

Mitogen-activated protein kinase (MAPK) signal transduction, as a highly conserved signaling pathway, is reported to be involved in various biological events, including metabolic reprogramming, cell proliferation, survival, and differentiation. Mutations in key molecules involved in MAPK/ERK signaling and dysregulation of this pathway are very common events in various human malignancies, which make the MAPK signaling a crucial signaling pathway participating in the regulation of glucose uptake by malignant cells and tumorigenesis. MicroRNAs (miRNAs), as small non-coding RNAs, are critical regulators of gene expression that play key roles in cancer initiation and progression. On the other hand, these small RNAs mutually regulate the MAPK signaling which is often overexpressed in the case of cancer progression; suggesting that crosstalk between miRNAs and this signaling pathway plays a pivotal role in the development of human cancers. Some miRNAs such as miR-20b, miR-34c-3p, miR-152, miR-181a, and miR-302b through inhibiting MAPK signaling, and miR-193a-3p, miR-330-3p, and miR-592 by activating this signaling pathway, play imperative roles in tumorigenesis. Therefore, in this review, we aimed to focus on the interplay between miRNAs and MAPK signaling in the various steps of tumorigenesis, including metabolic regulation, cell proliferation, apoptosis, metastasis, angiogenesis, and drug resistance. Mitogen-activated protein kinase (MAPK) signal transduction, as a highly conserved signaling pathway, is reported to be involved in various biological events, including metabolic reprogramming, cell proliferation, survival, and differentiation. Mutations in key molecules involved in MAPK/ERK signaling and dysregulation of this pathway are very common events in various human malignancies, which make the MAPK signaling a crucial signaling pathway participating in the regulation of glucose uptake by malignant cells and tumorigenesis. MicroRNAs (miRNAs), as small non-coding RNAs, are critical regulators of gene expression that play key roles in cancer initiation and progression. On the other hand, these small RNAs mutually regulate the MAPK signaling which is often overexpressed in the case of cancer progression; suggesting that crosstalk between miRNAs and this signaling pathway plays a pivotal role in the development of human cancers. Some miRNAs such as miR-20b, miR-34c-3p, miR-152, miR-181a, and miR-302b through inhibiting MAPK signaling, and miR-193a-3p, miR-330-3p, and miR-592 by activating this signaling pathway, play imperative roles in tumorigenesis. Therefore, in this review, we aimed to focus on the interplay between miRNAs and MAPK signaling in the various steps of tumorigenesis, including metabolic regulation, cell proliferation, apoptosis, metastasis, angiogenesis, and drug resistance.

Antioxidants are essential in preventing the formation and suppressing the activities of reactive nitrogen and oxygen species. The aim of this study was to review the role of antioxidants in cancer development or prevention. Antioxidants are believed to prevent and treat various types of malignancies. Currently, natural antioxidant compounds have been generally consumed to prevent and treat cancers. Certainly, phenolic compounds extracted from medicinal plants have opened a new prospect with respect to the prevention and treatment of cancers due to having antioxidant characteristics. However, some recently published studies have revealed that antioxidant compounds do not indicate absolute anti-tumor properties. Some antioxidants are helpful in cancer initiation and progression. Taken together, antioxidants demonstrate a two-faced nature toward cancer. However, it is required to conduct further cell culture and in vivo studies to confirm the exact role of antioxidants and then use them for efficient cancer treatments.

Triple-negative breast cancer (TNBC) is heterogeneous cancer with poor prognosis among the other breast tumors. Rapid recurrence and increased progression rate could be reasons for the poor prognosis of this type of breast cancer. Recently, because of the lack of specific targets in multiple cancer treatment, immune checkpoint blockade therapies with targeting PD-1/PD-L1 axis have displayed significant advances and improved survival. Among different types of breast cancers, TNBC is considered more immunogenic with high T-cell and other immune cells infiltration compared to other breast cancer subtypes. This immunogenic characteristic of TNBC is a beneficial marker in the immunotherapy of these tumors. Clinical studies with a focus on immune checkpoint therapy have demonstrated promising results in TNBC treatment. In this review, we summarize clinical trials with the immunotherapy-based treatment of different cancers and also discuss the interaction between infiltrating immune cells and breast tumor microenvironment. In addition, we focus on the signaling pathway that controls PD-L1 expression and continues with CAR T-cell therapy and siRNA as novel strategies and potential tools in targeted therapy.