Radiosensitizer EXO-miR-197-3p Inhibits Nasopharyngeal Carcinoma Progression and Radioresistance by Regulating the AKT/mTOR Axis and HSPA5-mediated Autophagy

BMSC-Exosomes attenuate ALP dysfunction by restoring lysosomal function via the mTOR/TFEB Axis to reduce cerebral ischemia-reperfusion injury

BACKGROUND

The complex pathophysiological changes following cerebral ischemia-reperfusion injury (CIRI) include the accumulation of defective proteins and damaged organelles, which cause massive neuron demise. To preserve cellular homeostasis, the autophagy-lysosomal pathway (ALP) is crucial for neurons to dispose of these substances. Many studies have shown that bone mesenchymal stem cell exosomes (BMSC-Exos) can reduce CIRI. However, the specific mechanisms have not been well elucidated, a fact that limits its widespread clinical use. This study aimed to clarify whether BMSC-Exos could attenuate ALP dysfunction by restoring lysosomal function after CIRI via inhibiting mTOR and then activating TFEB nucleus translocation.

METHODS

In this study, Flow cytometry, Nanoparticle tracking analysis (NTA), Transmission electron microscope (TEM), and Western blot were used to identify the BMSCs and BMSC-Exos used in this experiment as conforming to the requirements. In vivo experiments, SD rats were modeled with temporary middle cerebral artery occlusion (tMCAO), and BMSC-Exos was injected into the tail vein 2 h after modeling. Triphenyl tetrazolium chloride (TTC) staining, modified neurological severity scores (mNSS), corner turn test, and rotating rod test were used to detect neurological deficits in rats after BMSC-Exos intervention. Western blot and Immunofluorescence were used to detect ALP, transcription factor EB(TFEB) nucleus translocation, and mammalian target of rapamycin (mTOR) change at different time points after modeling and after BMSC-Exos intervention. In vitro experiments, pheochromocytoma cells (PC12) cells were subjected to oxygen-glucose deprivation and reperfusion (OGD/R) modeling to mimic CIRI, and were respectively intervened with BMSC-Exos, BMSC-Exos + MHY 1485 (the mTOR agonist), Rapamycin (the mTOR inhibitor). CCK8, Western blot, and Immunofluorescence were used to detect PC12 cell survival, TFEB nucleus translocation, and cathepsin B(CTSB) Immunofluorescence intensity.

RESULTS

We found that ALP dysfunction occurred 72 h after tMCAO, and BMSC-Exos can attenuate ALP dysfunction by restoring lysosomal function. Next, we examined TFEB nucleus translocation and the expression of mTOR, a key regulator of translocation. We found that BMSC-Exos could inhibit mTOR and activate TFEB nucleus translocation. Additional in vitro tests revealed that BMSC-Exos could increase PC12 cell survival after OGD/R, activating TFEB nucleus translocation and enhancing the fluorescence intensity of CTSB, which in turn could be reversed by the mTOR agonist, MHY1485. This effect was similar to another mTOR inhibitor, Rapamycin.

CONCLUSION

BMSC-Exos could attenuate ALP dysfunction by restoring lysosomal function after CIRI by inhibiting mTOR and then promoting TFEB nucleus translocation.

Tumor cell-derived exosomal miR-193b-3p promotes tumor-associated macrophage activation to facilitate nasopharyngeal cancer cell invasion and radioresistances

Background

Communication between cancer cells and tumor-associated macrophages (TAMs) in the tumor microenvironment (TME) plays a crucial role in accelerating nasopharyngeal cancer (NPC) metastasis and radioresistance. However, the mechanisms through which NPC cells regulate the properties and activation of TAMs during NPC progression are not yet fully understood.

Methods

A high-metastatic NPC subclone (HMC) and a low-metastatic NPC subclone (LMC) were screened from the CNE-2 cell line and exosomes were collected from HMCs and LMCs, respectively. The effects of HMC- and LMC-derived exosomes (HMC-Exos and LMC-Exos) on the regulation of TAM activation were evaluated by assessing the levels of inflammation-related or immunosuppression-related genes. The role of miRNA-193b-3p (miR-193b) in mediating communication between NPCs and TAMs was assessed using real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR), Western blot analysis, Transwell assays, and clonogenic survival assays.

Results

HMCs and HMC-Exos exhibited a greater capacity to facilitate macrophage protumorigenic activation than LMCs and LMC-Exos. miR-193b levels derived from HMC-Exos were higher than those from LMC-Exos, and miR-193b levels were higher in metastatic NPC tissue-derived TAMs than in non-metastatic NPC tissue-derived TAMs. The upregulated miR-193b was packaged into exosomes and transferred to macrophages. Functionally, miR-193b up-regulation accelerated TAM activation by directly targeting mitogen-activated protein/ERK kinase kinase 3 (MEKK3). As a result, miR-193b-overexpressed macrophages facilitated NPC cell invasion and radioresistance.

Conclusions

These data revealed a critical role for exosomal miR-193b in mediating intercellular communication between NPC cells and macrophages, providing a potential target for NPC treatment.

Radiotherapy Resistance of 3D Bioprinted Glioma via ITGA2/p-AKT Signaling Pathway

Due to the inherent radiation tolerance, patients who suffered from glioma frequently encounter tumor recurrence and malignant progression within the radiation target area, ultimately succumbing to treatment ineffectiveness. The precise mechanism underlying radiation tolerance remains elusive due to the dearth of in vitro models and the limitations associated with animal models. Therefore, a bioprinted glioma model is engineered, characterized the phenotypic traits in vitro, and the radiation tolerance compared to 2D ones when subjected to X-ray radiation is assessed. By comparing the differential gene expression profiles between the 2D and 3D glioma model, identify functional genes, and analyze distinctions in gene expression patterns. Results showed that 3D glioma models exhibited substantial alterations in the expression of genes associated with the stromal microenvironment, notably a significant increase in the radiation tolerance gene ITGA2 (integrin subunit A2). In 3D glioma models, the knockdown of ITGA2 via shRNA resulted in reduced radiation tolerance in glioma cells and concomitant inhibition of the p-AKT pathway. Overall, 3D bioprinted glioma model faithfully recapitulates the in vivo tumor microenvironment (TME) and exhibits enhanced resistance to radiation, mediated through the ITGA2/p-AKT pathway. This model represents a superior in vitro platform for investigating glioma radiotherapy tolerance.

Hsa-miR-92b-3p Targeting FHL2 to Enhance Radiosensitivity of Nasopharyngeal Carcinoma

Radiotherapy resistance is a major cause of treatment failure and leads to poor prognosis in nasopharyngeal carcinoma (NPC). Evidences indicate that microRNA (miRNAs) are closely associated with radiotherapy for NPC. In this study, we found that the expression level of miR-92b-3p was significantly higher in radiotherapy-sensitive NPC patients than in radiotherapy-resistant patients. High expression of miR-92b-3p was associated with good prognosis in patients with NPC, and high expression of FHL2 was associated with poor prognosis in patients with NPC. It was predicted that miR-92b-3p could directly target and bind FHL2. Overexpression of miR-92b-3p significantly inhibited FHL2 expression at the mRNA as well as protein levels, while inhibition of miR-92b-3p expression significantly upregulated FHL2 expression. Overexpression of miR-92b-3p significantly reduced proliferation and colony formation in NPC cells. Inhibition of miR-92b-3p attenuated the sensitivity of nasopharyngeal carcinoma to radiotherapy, while simultaneous inhibition of miR-92b-3p and FHL2 increased the sensitivity of NPC to radiotherapy. Our findings highlighted that miR-92b-3p is closely associated with radiotherapy sensitivity and prognosis in NPC patients and may improve the sensitivity of NPC to radiotherapy by targeting FHL2.

Unfolding the Complexity of Exosome-Cellular Interactions on Tumour Immunity and Their Clinical Prospects in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy situated in the posterolateral nasopharynx. NPC poses grave concerns in Southeast Asia due to its late diagnosis. Together with resistance to standard treatment combining chemo- and radiotherapy, NPC presents high metastatic rates and common recurrence. Despite advancements in immune-checkpoint inhibitors (ICIs) and cytotoxic-T-lymphocytes (CTLs)-based cellular therapy, the exhaustive T cell profile and other signs of immunosuppression within the NPC tumour microenvironment (TME) remain as concerns to immunotherapy response. Exosomes, extracellular vesicles of 30-150 nm in diameter, are increasingly studied and linked to tumourigenesis in oncology. These bilipid-membrane-bound vesicles are packaged with a variety of signalling molecules, mediating cell-cell communications. Within the TME, exosomes can originate from tumour, immune, or stromal cells. Although there are studies on tumour-derived exosomes (TEX) in NPC and their effects on tumour processes like angiogenesis, metastasis, therapeutic resistance, there is a lack of research on their involvement in immune evasion. In this review, we aim to enhance the comprehension of how NPC TEX contribute to cellular immunosuppression. Furthermore, considering the detectability of TEX in bodily fluids, we will also discuss the potential development of TEX-related biomarkers for liquid biopsy in NPC as this could facilitate early diagnosis and prognostication of the disease.

MiR-4524b-5p-targeting ALDH1A3 attenuates the proliferation and radioresistance of glioblastoma via PI3K/AKT/mTOR signaling

Increasing evidence has revealed a strong connection between the aldehyde dehydrogenase family member ALDH1A3 and tumorigenesis, therapy resistance, and prognosis in diverse types of cancer. However, the specific miRNA involved in the pathways that regulate ALDH1A3-mediated glioblastoma (GBM) radioresistance remains to be elucidated. In this study, we demonstrated a high expression of ALDH1A3 in GBM cells, which plays a critical role in their proliferation and radioresistance. We also identified miR-4524b-5p, which is downregulated in GBM, as the ALDH1A3 upstream regulator. Overexpression of miR-4524b-5p reduced proliferation and radioresistance in GBM cells. Moreover, silencing ALDH1A3 reduced PI3K/AKT/mTOR signaling and glycolytic activity in GBM cells, whereas inhibiting mTOR reversed the radioresistance effects of ALDH1A3 on these cells. In vivo experiments have evidenced that ALDH1A3 silencing and miR-4524b-5p overexpression significantly reduced tumor growth and GBM cells radioresistance. In summary, targeting the miR-4524b-5p and ALDH1A3 axis is a promising therapeutic strategy for treating GBM.

Nasopharyngeal carcinoma derived exosomes regulate the proliferation and migration of nasopharyngeal carcinoma cells by mediating the miR-99a-5p BAZ2A axis

OBJECTIVES

Nasopharyngeal Carcinoma (NPC) is a common malignant tumor of nasopharyngeal mucosal epithelium in clinical practice. Radiotherapy and chemotherapy are the main treatment methods at present, but the therapeutic effect is still unsatisfactory. Studies have shown that exosomes and microRNAs (miRNAs) play an important role in the development of cancer. Therefore, this study aimed to investigate the effects of NPC derived exosomes on NPC and their molecular mechanisms.

METHODS

Serum was collected from healthy subjects, Epstein-Barr Virus (EBV) infected patients and NPC patients (n = 9 group) and exosomes were extracted separately. High-throughput sequencing of exosomes was performed to screen differentially expressed miRNAs. The function of the screened miRNA was identified by treating NPC cells with exosomes. The target gene of miRNA was identified using the dual-luciferase assay. Real-Time quantitative Polymerase Chain Reaction (RT-qPCR) was used to determine the levels of miR-99a-5p and Bromodomain Adjacent Tozinc finger domain protein 2A (BAZ2A). Cell Counting Kit-8 assay, flow cytometry, and wound healing assay were utilized to detect cell viability, cell cycle and apoptosis, and migration ability. The protein levels were evaluated by Western blot.

RESULTS

MiR-99a-5p was identified as the most significant differentially expressed miRNA in exosomes (p < 0.05). The proliferation and migration of NPC cells were extremely facilitated by exosomes, accompanied by the suppressed apoptosis, upregulated BAZ2A, Monocyte Chemotactic Protein-1 (MCP1), and Vascular Endothelial Growth Factor A (VEGFA), and downregulation of Interleukin (IL)-1β and Nuclear Transcription Factor-κB (NF-κB) (p < 0.05). BAZ2A was a target gene of miR-99a-5p. Furthermore, the regulatory effect of exosomes on the proliferation, migration, and apoptosis was significantly abolished by overexpression of miR-99a-5p or downregulation of BAZ2A (p < 0.05).

CONCLUSION

NPC derived exosomes facilitated the proliferation and migration of NPC through regulating the miR-99a-5p/BAZ2A axis.

MiRNA signatures in nasopharyngeal carcinoma: molecular mechanisms and therapeutic perspectives

Nasopharyngeal carcinoma (NPC) is a prevalent cancerous tumor that affects the head and neck region. Recent studies have provided compelling evidence indicating the significant involvement of microRNAs (miRNAs) in the development and progression of NPC. This review aims to present a comprehensive summary of the current knowledge regarding miRNA signatures in NPC, encompassing their expression patterns, molecular mechanisms, and potential therapeutic implications. Initially, the article outlines the aberrant expression of miRNAs in NPC and elucidates their roles in tumor initiation, invasion, and metastasis. Subsequently, the underlying molecular mechanisms of miRNA-mediated regulation of NPC-associated signaling pathways are discussed. Additionally, the review highlights the potential clinical applications of miRNAs as diagnostic and prognostic biomarkers, as well as their therapeutic potential in NPC treatment. In conclusion, this review underscores the critical involvement of miRNAs in NPC pathogenesis and underscores their promise as novel therapeutic targets for combating this devastating disease.

Characterization of serum extracellular vesicles and their differential level of miR-197-3p in familial Mediterranean fever patients

OBJECTIVES

The aim of this study was to analyze the existence of miRNAs derived from serum extracellular vesicles (EVs) in familial Mediterranean fever (FMF) patients. Our group has previously shown the association of certain miRNAs with FMF.

METHODS

Serum samples of adult and pediatric FMF patients and their age matched controls were used in the study. Serum EVs were characterized by transmission electron microscopy (TEM) and flow cytometry. RNAs were isolated from EVs and levels of miR-197-3p and miR-20a-5p were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

EV characterization using TEM demonstrated fraction of 30-120 nm-sized particles with cup-shaped morphology. Flow cytometry results revealed the CD63 and CD81 positive populations as 53.3% in serum EVs. We showed that miR-197-3p and miR-20a-5p were "circulating miRNAs" and carried in EVs of FMF patients and controls. In FMF patients, level of miR-197-3p was significantly decreased. There was no significant alteration in the level for miR-20a-5p between patients and controls.

CONCLUSION

We showed the differential level of miR-197-3p in serum EVs of the FMF patients. miR-197-3p's potential as a biomarker and therapeutic target in FMF pathogenesis warrants further investigation.

Enhancing nasopharyngeal carcinoma cell radiosensitivity by suppressing AKT/mTOR via CENP-N knockdown

OBJECTIVE

Investigating the impact of centromere protein N (CENP-N) on radiosensitivity of nasopharyngeal carcinoma (NPC) cells.

METHODS

Using immunohistochemistry and immunofluorescence to detect CENP-N expression in tissues from 35 patients with radiosensitive or radioresistant NPC. Assessing the effect of combined CENP-N knockdown and radiotherapy on various cellular processes by CCK-8, colony formation, flow cytometry, and Western blotting. Establishing a NPC xenograft model. When the tumor volume reached 100 mm3, a irradiation dose of 6 Gy was given, and the effects of the combined treatment were evaluated in vivo using immunofluorescence and Western blotting techniques.

RESULTS

The level of CENP-N was significantly reduced in radiosensitive tissues of NPC (p < 0.05). Knockdown of CENP-N enhanced NPC radiosensitivity, resulting in sensitizing enhancement ratios (SER) of 1.44 (5-8 F) and 1.16 (CNE-2Z). The combined treatment showed significantly higher levels of proliferation suppression, apoptosis, and G2/M phase arrest (p < 0.01) compared to either CENP-N knockdown alone or radiotherapy alone. The combined treatment group showed the highest increase in Bax and γH2AX protein levels, whereas the protein Cyclin D1 exhibited the greatest decrease (p < 0.01). However, the above changes were reversed after treatment with AKT activator SC79. In vivo, the mean volume and weight of tumors in the radiotherapy group were 182 ± 54 mm3 and 0.16 ± 0.03 g. The mean tumor volume and weight in the combined treatment group were 84 ± 42 mm3 and 0.04 ± 0.01 g.

CONCLUSION

Knockdown of CENP-N can enhance NPC radiosensitivity by inhibiting AKT/mTOR.

Leukoreduction of red blood cell units decreases dysregulatory micro RNAs during routine storage: An observational study with In-silico analysis

BACKGROUND

Red Blood cells (RBCs) bring about harmful consequences during storage. MicroRNA (miRNA) dysregulation in stored RBCs could represent potential biomarkers of storage lesions. Although leukoreduction prevents damage to RBCs, it is uncertain whether leukoreduction of RBCs would impact the dysregulation of miRNAs during storage. This study evaluated the potential role of miRNAs for any alteration of leukoreduced (LR) and non-leukoreduced (NLR) RBCs till 21 days of storage.

STUDY DESIGN AND METHODS

In this prospective study, thirty male volunteers' blood was equally divided into leukoreduced RBCs (LR) and NLR RBC (NLR) bags and stored till Day 21 at 4-60c. Selected miRNAs were quantified on Days 0 and 21. Further, bioinformatic tools were used to analyze the selected miRNAs and their predicted target genes (mRNAs) and identify the miRNA-mRNA regulatory relationships.

RESULTS

A significantly higher fold change values of three miRNAs (miR-96-5p, miR-197-3p, miR-769-3p) were observed in NLR RBCs (p < .05). A significantly higher (p < .05) expression levels of miR-150-5p and miR-197-3p were observed in NLR RBCs till 21 days of storage. Further, the correlation with mRNA quantification confirmed the regulatory role of these miRNAs upon functional pathway enrichment analysis.

DISCUSSION

A higher level of dysregulation of miRNAs was observed in NLR RBCs. Validation from In-Silico analysis suggested the regulatory role of miRNAs in cell apoptosis, senescence, and RBC-related signaling pathways. This indicated that stored LR RBCs would likely have better in vivo survival and function following transfusion. However, an in vivo study of miRNA in RBCs is warranted for conclusive evidence.

Recent Advances in Extracellular Vesicles in Amyotrophic Lateral Sclerosis and Emergent Perspectives

Amyotrophic lateral sclerosis (ALS) is a severe and incurable neurodegenerative disease characterized by the progressive death of motor neurons, leading to paralysis and death. It is a rare disease characterized by high patient-to-patient heterogeneity, which makes its study arduous and complex. Extracellular vesicles (EVs) have emerged as important players in the development of ALS. Thus, ALS phenotype-expressing cells can spread their abnormal bioactive cargo through the secretion of EVs, even in distant tissues. Importantly, owing to their nature and composition, EVs' formation and cargo can be exploited for better comprehension of this elusive disease and identification of novel biomarkers, as well as for potential therapeutic applications, such as those based on stem cell-derived exosomes. This review highlights recent advances in the identification of the role of EVs in ALS etiopathology and how EVs can be promising new therapeutic strategies.

New progresses on cell surface protein HSPA5/BiP/GRP78 in cancers and COVID-19

Heat-shock-protein family A (Hsp70) member 5 (HSPA5), aliases GRP78 or BiP, is a protein encoded with 654 amino acids by the HSPA5 gene located on human chromosome 9q33.3. When the endoplasmic reticulum (ER) was stressed, HSPA5 translocated to the cell surface, the mitochondria, and the nucleus complexed with other proteins to execute its functions. On the cell surface, HSPA5/BiP/GRP78 can play diverse functional roles in cell viability, proliferation, apoptosis, attachments, and innate and adaptive immunity regulations, which lead to various diseases, including cancers and coronavirus disease 2019 (COVID-19). COVID-19 is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which caused the pandemic since the first outbreak in late December 2019. HSPA5, highly expressed in the malignant tumors, likely plays a critical role in SARS-CoV-2 invasion/attack in cancer patients via tumor tissues. In the current study, we review the newest research progresses on cell surface protein HSPA5 expressions, functions, and mechanisms for cancers and SARS-CoV-2 invasion. The therapeutic and prognostic significances and prospects in cancers and COVID-19 disease by targeting HSPA5 are also discussed. Targeting HSPA5 expression by natural products may imply the significance in clinical for both anti-COVID-19 and anti-cancers in the future.

Radiosensitization of Nasopharyngeal Carcinoma by Graphene Oxide Nanosheets to Reduce Bcl-2 Level

There are many treatments for nasopharyngeal carcinoma (NPC), but none of them are very effective. Radiotherapy is used extensively in NPC treatment, but radioresistance is a major problem. Graphene oxide (GO) has been previously studied in cancer treatment, and this study is aimed to explore its role in radiosensitization of NPC. Therefore, graphene oxide nanosheets were prepared, and the relationship between GO and radioresistance was explored. The GO nanosheets were synthesized by a modified Hummers' method. The morphologies of the GO nanosheets were characterized by field-emission environmental scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The morphological changes and radiosensitivity of C666-1 and HK-1 cells with or without the GO nanosheets were observed by an inverted fluorescence microscopy and laser scanning confocal microscopy (LSCM). Colony formation assay and Western Blot were applied for analysis of NPC radiosensitivity. The as-synthesized GO nanosheets have lateral dimensions (sizes ∼1 μm) and exhibit a thin wrinkled two-dimensional lamellar structure with slight folds and crimped edges (thickness values ∼1 nm). C666-1 cells with the GO was significantly changed the morphology of cells postirradiation. The full field of view visualized by a microscope showed the shadow of dead cells or cell debris. The synthesized graphene oxide nanosheets inhibited cell proliferation, promoted cell apoptosis, and inhibited the expression of Bcl-2 in C666-1 and HK-1 cells but increased the level of Bax. The GO nanosheets could affect the cell apoptosis and reduce the pro-survival protein Bcl-2 related to the intrinsic mitochondrial pathway. The GO nanosheets could enhance radiosensitivity, which might be a radioactive material in NPC cells.

Extracellular Vesicles as Biomarkers in Head and Neck Squamous Cell Carcinoma: From Diagnosis to Disease-Free Survival

Head and neck squamous cell carcinomas (HNSCCs) arising from different anatomical sites present with different incidences and characteristics, which requires a personalized treatment strategy. Despite the extensive research that has conducted on this malignancy, HNSCC still has a poor overall survival rate. Many attempts have been made to improve the outcomes, but one of the bottlenecks is thought to be the lack of an effective biomarker with high sensitivity and specificity. Extracellular vesicles (EVs) are secreted by various cells and participate in a great number of intercellular communications. Based on liquid biopsy, EV detection in several biofluids, such as blood, saliva, and urine, has been applied to identify the existence and progression of a variety of cancers. In HNSCC, tumor-derived EVs exhibit many functionalities by transporting diverse cargoes, which highlights their importance in tumor screening, the determination of multidisciplinary therapy, prediction of prognosis, and evaluation of therapeutic effects. This review illustrates the classification and formation of EV subtypes, the cargoes conveyed by these vesicles, and their respective functions in HNSCC cancer biology, and discloses their potential as biomarkers during the whole process of tumor diagnosis, treatment, and follow-up.

Autophagy as a self-digestion signal in human cancers: Regulation by microRNAs in affecting carcinogenesis and therapy response

Autophagy is defined as a "self-digestion" signal, and it is a cell death mechanism its primary function is degrading toxic agents and aged organelles to ensure homeostasis in cells. The basic leve ls of autophagy are found in cells, and when its levels exceed to standard threshold, cell death induction is observed. Autophagy dysregulation in cancer has been well-documented, and regulation of this pathway by epigenetic factors, especially microRNAs (miRNAs), is interesting and noteworthy. miRNAs are considered short endogenous RNAs that do not encode functional proteins, and they are essential regulators of cell death pathways such as apoptosis, necroptosis, and autophagy. Accumulating data has revealed miRNA dysregulation (upregulation or downregulation) during tumor progression, and their therapeutic manipulation provides new insight into cancer therapy. miRNA/autophagy axis in human cancers has been investigated an exciting point is the dual function of both autophagy and miRNAs as oncogenic and onco-suppressor factors. The stimulation of pro-survival autophagy by miRNAs can increase the survival rate of tumor cells and mediates cancer metastasis via EMT inductionFurthermore, pro-death autophagy induction by miRNAs has a negative impact on the viability of tumor cells and decreases their survival rate. The miRNA/autophagy axis functions beyond regulating the growth and invasion of tumor cells, and they can also affect drug resistance and radio-resistance. These subjects are covered in the current review regarding the new updates provided by recent experiments.

Does miR-197 Represent a Valid Prognostic Biomarker in Head and Neck Squamous Cell Carcinoma (HNSCC)? A Systematic Review and Trial Sequential Analysis

(1) Background: Between tumors of the head and neck region, the squamous cell variant (HNSCC) is the most common and represents one of the main neoplasms affecting humans. At the base of carcinogenesis processes, there are genetic alterations whose regulation can be influenced by changes in the expression of microRNA (miR). Consequently, despite recent studies indicating miR-197 as a potential prognostic biomarker of survival for many varieties of cancer, there are currently no systematic reviews and trial sequential/bioinformatics/meta-analysis regarding the role of miR-197 in HNSCC. Our hypothesis was that with the existing literature, it is possible to clarify whether the different expressions of miR-197 in neoplastic tissues can represent a prognostic biomarker of survival in head and neck tumors. (2) Methods: The systematic review was reported following the indications of PRISMA and by consulting six electronic databases (including one register). Moreover, this review was carried out using the Kaplan–Meier plotter database portal, and hazard ratio (HR) data were extracted. Finally, a trial sequential analysis (TSA) was conducted to test the robustness of the proposed meta-analysis. (3) Results: This search identified 1119 articles and outcomes of the meta-analysis, reporting an aggregate HR for overall survival (OS) between the highest and lowest miR-197 expression of 1.01, 95% CI: [1.00, 1.02]. (4) Conclusions: We can state that, from the literature data included in the present meta-analysis, and from the TSA and bioinformatics analysis data, miR-197 does not currently represent a valid prognostic biomarker for HNSCC, although the data provided by the Kaplan–Meier plotter suggest that miR-197 can serve as a putative biomarker in short-term (5 years) survival.

Small biomarkers with massive impacts: PI3K/AKT/mTOR signalling and microRNA crosstalk regulate nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is one of the most common malignant tumours of the head and neck in Southeast Asia and southern China. The Phosphatidylinositol 3-kinase/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signalling pathway is involved in processes related to tumour initiation/progression, such as proliferation, apoptosis, metastasis, and drug resistance, and is closely related to the clinicopathological features of NPC. In addition, key genes involved in the PI3K/AKT/mTOR signalling pathway undergo many changes in NPC. More interestingly, a growing body of evidence suggests an interaction between this signalling pathway and microRNAs (miRNAs), a class of small noncoding RNAs. Therefore, in this review, we discuss the interactions between key components of the PI3K/AKT/mTOR signalling pathway and various miRNAs and their importance in NPC pathology and explore potential diagnostic biomarkers and therapeutic targets.

Functional Properties of Cancer Epithelium and Stroma-Derived Exosomes in Head and Neck Squamous Cell Carcinoma

Stroma–cancer cell crosstalk involves a complex signaling network that contributes to tumor progression, including carcinogenesis, angiogenesis, migration, invasion, and therapy resistance in cancers. Exosomes, as extracellular membranous nanovesicles released by almost all types of cells, including tumor cells and stromal cells, play a critical role in signal delivery and material communication, in which the characteristics of their parent cells are reflected. The tumor or stroma-derived exosomes mediate cell–cell communication in the tumor microenvironment by transporting DNA, RNA, proteins, lipids, and metabolites. Recent studies on head and neck squamous cell carcinoma (HNSCC) have demonstrated that tumor-derived exosomes support various tumor biological behaviors, whereas the functional roles of stroma-derived exosomes remain largely unknown. Although these exosomes are emerging as promising targets in early diagnosis, prognostic prediction, and pharmaceutical carriers for antitumor therapy, there are still multiple hurdles to be overcome before they can be used in clinical applications. Herein, we systematically summarize the promotive roles of the epithelium and stroma-derived exosomes in HNSCC and highlight the potential clinical applications of exosomes in the treatment of HNSCC.