Exosomal lncRNA PCAT-1 promotes Kras-associated chemoresistance via immunosuppressive miR-182/miR-217 signaling and p27/CDK6 regulation

Unraveling the role of long non-coding RNAs in therapeutic resistance in acute myeloid leukemia: New prospects & challenges

Acute Myeloid Leukemia (AML) is a fatal hematological disease characterized by the unchecked proliferation of immature myeloid blasts in different tissues developed by various mutations in hematopoiesis. Despite intense chemotherapeutic regimens, patients often experience poor outcomes, leading to substandard remission rates. In recent years, long non-coding RNAs (lncRNAs) have increasingly become important prognostic and therapeutic hotspots, due to their contributions to dysregulating many functional epigenetic, transcriptional, and post-translational mechanisms leading to alterations in cell expressions, resulting in increased chemoresistance and reduced apoptosis in leukemic cells. Through this review, I highlight and discuss the latest advances in understanding the major mechanisms through which lncRNAs confer therapy resistance in AML. In addition, I also provide perspective on the current strategies to target lncRNA expressions. A better knowledge of the critical role that lncRNAs play in controlling treatment outcomes in AML will help improve existing medications and devise new ones.

Dissecting the roles of exosomal cancer-associated fibroblasts-derived non-coding RNAs in tumor progression: A complete guide

Cancer-associated fibroblasts are the most important cellular component of the tumor microenvironment, controlling cancer progression and therapeutic response. These cells in the tumor microenvironment regulate tumor progression and development as oncogenic or tumor suppressor agents. However, the mechanisms by which CAFs communicate with cancer cells remain to investigate. Here, we review evidence that extracellular vesicles, particularly exosomes, serve as vehicles for the intercellular transfer of bioactive cargos, notably microRNAs and long non-coding RNAs, from CAFs to cancer cells. We try to highlight molecular pathways of non-coding RNAs and the interaction among these molecules. Together, these findings elucidate a critical exosome-based communication axis by which CAFs create mostly a supportive pro-tumorigenic microenvironment and highlight therapeutic opportunities for disrupting this intercellular crosstalk.

Connecting the dots: LncRNAs in the KRAS pathway and cancer

Long non-coding RNAs (lncRNAs) have been identified as important participants in several biological functions, particularly their complex interactions with the KRAS pathway, which provide insights into the significant roles lncRNAs play in cancer development. The KRAS pathway, a central signaling cascade crucial for cell proliferation, survival, and differentiation, stands out as a key therapeutic target due to its aberrant activation in many human cancers. Recent investigations have unveiled a myriad of lncRNAs, such as H19, ANRIL, and MEG3, intricately modulating the KRAS pathway, influencing both its activation and repression through various mechanisms, including epigenetic modifications, transcriptional regulation, and post-transcriptional control. These lncRNAs function as fine-tuners, delicately orchestrating the balance required for normal cellular function. Their dysregulation has been linked to the development and progression of multiple malignancies, including lung, pancreatic, and colorectal carcinomas, which frequently harbor KRAS mutations. This scrutiny delves into the functional diversity of specific lncRNAs within the KRAS pathway, elucidating their molecular mechanisms and downstream effects on cancer phenotypes. Additionally, it underscores the diagnostic and prognostic potential of these lncRNAs as indicators for cancer detection and assessment. The complex regulatory network that lncRNAs construct within the context of the KRAS pathway offers important insights for the creation of focused therapeutic approaches, opening new possibilities for precision medicine in oncology. However, challenges such as the dual roles of lncRNAs in different cancer types and the difficulty in therapeutically targeting these molecules highlight the ongoing debates and need for further research. As ongoing studies unveil the complexities of lncRNA-mediated KRAS pathway modulation, the potential for innovative cancer interventions becomes increasingly promising.

Identification of CAF-related lncRNAs at the pan-cancer level represents a potential carcinogenic risk

Cancer-associated fibroblasts (CAFs) are increasingly recognized as playing a crucial role in regulating cancer progression and metastasis. These cells can be activated by long non-coding RNAs (lncRNAs), promoting the malignant biological processes of tumor cells. Therefore, it is essential to understand the regulatory relationship between CAFs and lncRNAs in cancers. Here, we identified CAF-related lncRNAs at the pan-cancer level to systematically predict their potential regulatory functions. The identified lncRNAs were also validated using various external data at both tissue and cellular levels. This study has revealed that these CAF-related lncRNAs exhibit expression perturbations in cancers and are highly correlated with the infiltration of stromal cells, particularly fibroblasts and endothelial cells. By prioritizing a list of CAF-related lncRNAs, we can further distinguish patient subtypes that show survival and molecular differences. In addition, we have developed a web server, CAFLnc (https://46906u5t63.zicp.fun/CAFLnc/), to visualize our results. In conclusion, CAF-related lncRNAs hold great potential as a valuable resource for comprehending lncRNA functions and advancing the identification of biomarkers for cancer progression and therapeutic targets in cancer treatment.

Exosome regulation of immune response mechanism: Pros and cons in immunotherapy

Due to its multiple features, including the ability to orchestrate remote communication between different tissues, the exosomes are the extracellular vesicles arousing the highest interest in the scientific community. Their size, established as an average of 30-150 nm, allows them to be easily uptaken by most cells. According to the type of cells-derived exosomes, they may carry specific biomolecular cargoes used to reprogram the cells they are interacting with. In certain circumstances, exosomes stimulate the immune response by facilitating or amplifying the release of foreign antigens-killing cells, inflammatory factors, or antibodies (immune activation). Meanwhile, in other cases, they are efficiently used by malignant elements such as cancer cells to mislead the immune recognition mechanism, carrying and transferring their cancerous cargoes to distant healthy cells, thus contributing to antigenic invasion (immune suppression). Exosome dichotomic patterns upon immune system regulation present broad advantages in immunotherapy. Its perfect comprehension, from its early biogenesis to its specific interaction with recipient cells, will promote a significant enhancement of immunotherapy employing molecular biology, nanomedicine, and nanotechnology.

Alleviation of DSS-induced colitis via bovine colostrum-derived extracellular vesicles with microRNA let-7a-5p is mediated by regulating Akkermansia and -hydroxybutyrate in gut environments

IMPORTANCE

Even though studying on the possible involvement of extracellular vesicles (EVs) in host-microbe interactions, how these relationships mediate host physiology has not clarified yet. Our current findings provide insights into the encouraging benefits of dietary source-derived EVs and microRNAs (miRNAs) on organic acid production and ultimately stimulating gut microbiome for human health, suggesting that supplementation of dietary colostrum EVs and miRNAs is a novel preventive strategy for the treatment of inflammatory bowel disease.

Long non-coding RNAs in non-small cell lung cancer: implications for preventing therapeutic resistance

Lung cancer has the highest mortality and morbidity rates among all cancers worldwide. Despite many complex treatment options, including radiotherapy, chemotherapy, targeted drugs, immunotherapy, and combinations of these treatments, efficacy is low in cases of resistance to therapy, metastasis, and advanced disease, contributing to low overall survival. There is a pressing need for the discovery of novel biomarkers and therapeutic targets for the early diagnosis of lung cancer and to determine the efficacy and outcomes of drug treatments. There is now substantial evidence for the diagnostic and prognostic value of long noncoding RNAs (lncRNAs). This review briefly discusses recent findings on the roles and mechanisms of action of lncRNAs in the responses to therapy in non-small cell lung cancer.

Functions and mechanisms of lncRNA MALAT1 in cancer chemotherapy resistance

Chemotherapy is one of the most important treatments for cancer therapy. However, chemotherapy resistance is a big challenge in cancer treatment. Due to chemotherapy resistance, drugs become less effective or no longer effective at all. In recent years, long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been found to be associated with the development of chemotherapy resistance, suggesting that MALAT1 may be an important target to overcome chemotherapy resistance. In this review, we introduced the main mechanisms of chemotherapy resistance associated with MALAT1, which may provide new approaches for cancer treatment.

RAS: Circuitry and therapeutic targeting

Cancer has affected the lives of millions worldwide and is truly regarded as a devastating disease process. Despite advanced understanding of the genomic underpinning of cancer development and progression, therapeutic challenges are still persistent. Among all the human cancers, around 33% are attributed to mutations in RAS oncogene, a crucial component of the signaling pathways. With time, our understanding of RAS circuitry has improved and now the fact that it activates several downstream effectors, depending on the type and grades of cancer has been established. The circuitry is controlled via post-transcriptional mechanisms and frequent distortions in these mechanisms lead to important metabolic as well as immunological states that favor cancer cells' growth, survival, plasticity and metastasis. Therefore, understanding RAS circuitry can help researchers/clinicians to develop novel and potent therapeutics that, in turn, can save the lives of patients suffering from RAS-mutant cancers. There are many challenges presented by resistance and the potential strategies with a particular focus on novel combinations for overcoming these, that could move beyond transitory responses in the direction of treatment. Here in this review, we will look at how understanding the circuitry of RAS can be put to use in making strategies for developing therapeutics against RAS- driven malignancies.

An exosome-related long non-coding RNAs risk model could predict survival outcomes in patients with breast cancer

Breast cancer (BC) is one of the most frequent malignancies among women worldwide. Accumulating evidence indicates that long non-coding RNA (lncRNA) may affect BC progression. Exosomes, a class of small membrane vesicles, have been reported to promote tumor progression through transporting proteins, mRNAs, lncRNAs and some other small molecules. However, the interaction between exosome-related lncRNAs and the microenvironment of malignancies is unclear. Hence, we proceeded to investigate the relationship between exosome-related lncRNAs and BC microenvironment. 121 exosome-associated genes were extracted from ExoBCD database. Then, the Pearson analysis was used to screened out the exosome-related lncRNAs. After that, 15 exosome-related differentially expressed lncRNAs were identified by the correlation with BC prognosis. According to the sum of the expression of these 15 lncRNAs, extracted from The Cancer Genome Atlas, and the regression coefficients, an exosome-related lncRNAs signature was developed by using Cox regression analysis. With the median risk score of the training set, the patients in training and validation sets were separated to low-risk group and high-risk group. Subsequently, the lncRNA-mRNA co-expression network was constructed. The distinct enrichment pathways were compared among the different risk groups by using the R package clusterProfiler. The ESTIMATE method and ssGESA database were adopted to study the ESTIMATE Score and immune cell infiltration. Eventually, the expression of immune checkpoint associated genes, microsatellite instable and the immunophenoscore were further analyzed between different risk groups. Different risk groups exhibited different prognosis, with lower survival rate in the high-risk group. The differentially expressed genes between the different risk groups were enriched in biological processes pathways as well as immune responses. BC patients in high-risk group were identified with lower scores of ESTIMATE scores. Subsequently, we noticed that the infiltrating levels of aDCs, B cells, CD8+ T cells, iDCs, DCs, Neutrophils, macrophages, NK cells, pDCs, Tfh, T helper cells, TIL and Tregs were obvious elevated with the decreased risk score in training and validation cohorts. And some immune signatures were significantly activated with the decreased risk score in both cohorts. Eventually, the exosome-associated lncRNAs risk model was demonstrated to accurately predict immunotherapy response in patients with BC. The results of our study suggest that exosome-related lncRNAs risk model has close relationship with prognosis and immune cells infiltration in BC patients. These findings could make a great contribution to improving BC immunotherapy.

Extracellular Vesicle (EVs) Associated Non-Coding RNAs in Lung Cancer and Therapeutics

Lung cancer is one of the most lethal forms of cancer, with a very high mortality rate. The precise pathophysiology of lung cancer is not well understood, and pertinent information regarding the initiation and progression of lung cancer is currently a crucial area of scientific investigation. Enhanced knowledge about the disease will lead to the development of potent therapeutic interventions. Extracellular vesicles (EVs) are membrane-bound heterogeneous populations of cellular entities that are abundantly produced by all cells in the human body, including the tumor cells. A defined class of EVs called small Extracellular Vesicles (sEVs or exosomes) carries key biomolecules such as RNA, DNA, Proteins and Lipids. Exosomes, therefore, mediate physiological activities and intracellular communication between various cells, including constituent cells of the tumor microenvironment, namely stromal cells, immunological cells, and tumor cells. In recent years, a surge in studying tumor-associated non-coding RNAs (ncRNAs) has been observed. Subsequently, studies have also reported that exosomes abundantly carry different species of ncRNAs and these exosomal ncRNAs are functionally involved in cancer initiation and progression. Here, we discuss the function of exosomal ncRNAs, such as miRNAs and long non-coding RNAs, in the pathophysiology of lung tumors. Further, the future application of exosomal-ncRNAs in clinics as biomarkers and therapeutic targets in lung cancer is also discussed due to the multifaceted influence of exosomes on cellular physiology.

LncRNA-miRNA axis in tumor progression and therapy response: An emphasis on molecular interactions and therapeutic interventions

Epigenetic factors are critical regulators of biological and pathological mechanisms and they could interact with different molecular pathways. Targeting epigenetic factors has been an idea approach in disease therapy, especially cancer. Accumulating evidence has highlighted function of long non-coding RNAs (lncRNAs) as epigenetic factors in cancer initiation and development and has focused on their association with downstream targets. microRNAs (miRNAs) are the most well-known targets of lncRNAs and present review focuses on lncRNA-miRNA axis in malignancy and therapy resistance of tumors. LncRNA-miRNA regulates cell death mechanisms such as apoptosis and autophagy in cancers. This axis affects tumor metastasis via regulating EMT and MMPs. Besides, lncRNA-miRNA axis determines sensitivity of tumor cells to chemotherapy, radiotherapy and immunotherapy. Based on the studies, lncRNAs can be affected by drugs and genetic tools in cancer therapy and this may affect expression level of miRNAs as their downstream targets, leading to cancer suppression/progression. LncRNAs have both tumor-promoting and tumor-suppressor functions in cancer and this unique function of lncRNAs has complicated their implication in tumor therapy. LncRNA-miRNA axis can also affect other signaling networks in cancer such as PI3K/Akt, STAT3, Wnt/β-catenin and EZH2 among others. Notably, lncRNA/miRNA axis can be considered as a signature for diagnosis and prognosis in cancers.

Engineered Hybrid Treg-Targeted Nanosomes Restrain Lung Immunosuppression by Inducing Intratumoral CD8+T Cell Immunity

Introduction

Tumor immunotherapy is a key therapeutic paradigm for the treatment of several malignancies. However, in metastatic lung cancer, classical immunotherapy regimes are ineffective due to regulatory T cell (Treg)-related immunosuppression and tumor relapse.

Materials

To address this issue, we designed specific biocompatible Treg-targeted nanocarriers (NCs) as a model of immune-based nanotherapy, in order to target Treg-related immunosuppression in the lung tumor microenvironment. This is achieved through the combination of Dasatinib and Epacadostat integrated into biodegradable nanosomes which can inhibit and reverse Treg-supporting immunosuppression. Flow cytometry and immunofluorescence analysis, PET/CT scan, PTT/PA imaging and the Balb/c tumor model were used to explore the anti-tumor effect of Treg-targeted NCs both in vitro and in vivo.

Results

Findings reveal that NC treatment triggered substantial tumor cell apoptosis and drastically decreased tumor volume followed by downregulation of Ki-67 antigen expression, respectively. Drug circulation time was also increased as shown by biodistribution analysis accompanied by greater accumulation in lung and peripheral tissues. Intratumoral Th1 cytokines’ expression was also increased, especially TNF-A, IL-12 by 42%, and IL-6 by 18% compared to PBS treatment. In addition, the presence of mature CD80⁺/CD86⁺dendritic cells (DCs) revealed T cell enrichment and a decline in MDSC infiltration and myeloid subsets. Interestingly, a significant decline of Gr/CD11b myeloid cell population in blood and tissue samples was also observed. This immune activation can be attributed to the enhanced PTT efficiency and tumor targeting ability of the nanospheres which under near infrared (NIR) exposure can prompt highly efficient tumor ablation. We also demonstrated their therapeutic efficacy against 4T1 metastatic breast cancer model. Additionally, the photothermal therapy in combination with PD-L1 checkpoint blockade therapy exerted long-term tumor control over both primary and distant tumors.

Discussion

Overall, our findings present a novel nano-enabled platform for the inhibition of Treg-dependent immunosuppression in NSCLC and provide a novel nanotherapeutic strategy for the treatment of metastatic neoplasia.

Exosomal lncRNA PCAT1 Promotes Tumor Circulating Cell-Mediated Colorectal Cancer Liver Metastasis by Regulating the Activity of the miR-329-3p/Netrin-1-CD146 Complex

Objective

This study explored the colorectal cancer exosome lncRNA prostate cancer associated transcript 1– (PCAT1) mediated circulating tumors and the mechanism of cell colorectal cancer liver metastasis.

Methods

Exosomes were extracted from the primary colorectal cancer (CRC) cell lines HCT116 and SW480 and cultured with T84 and human umbilical vein endothelial (HUVE) cells. The expression of PCAT1 and miR-329-3p was detected by real-time quantitative polymerase chain reaction (RT-qPCR), the expression of Netrin-1, CD146, and epithelial mesenchymal transition (EMT) related proteins was detected by Western blot, the proliferation activity of T84 cells was detected by cell counting kit 8 (CCK-8), and cell migration was detected by Transwell. The expression of the F-actin signal was detected by immunofluorescence after coculture of exosomes with human umbilical vein endothelial cells (HUVECs). Changes in subcutaneous tumor and liver nodule size after PCAT1 deletion were observed in a mouse model of liver metastasis from rectal cancer.

Results

PCAT1 expression was upregulated in primary cell lines and their exosomes. After exosomes were cocultured with colorectal cancer tumor circulating T84 cells, the expression of Netrin-1 and CD146 was upregulated, the expression of miR-329-3p was downregulated, the proliferation and migration ability of T84 cells were enhanced, and EMT occurred. After knocking down PCAT1, the above phenomenon was reversed. Similarly, after exosomes were cocultured with HUVECs, the expression of the F-actin signal increased, and after PCAT1 was knocked down, the F-actin signal also decreased. PCAT1 regulates miR-329-3p/Netrin-1 and affects the biological behavior of T84 and F-actin signal expression in HUVECs. In a mouse model of colorectal cancer liver metastasis, knocking down PCAT1 significantly reduced the nodules formed by liver metastasis in mice.

Conclusions

LncRNA PCAT1 derived from colorectal cancer exosomes regulates the activity of the Netrin-1-CD146 complex in circulating tumor cells (CTCs) to promote the occurrence of colorectal cancer EMT and liver metastasis and provides new molecular targets for the treatment of colorectal cancer liver metastasis.

[Effect of modified titanium loaded with endothelial progenitor cells-exosomes on osteogenic and angiogenic differentiations of adipose-derived stem cells]

OBJECTIVE

To investigate the effects of titanium modified by ultrasonic acid etching/anodic oxidation (UAT) loaded with endothelial progenitor cells-exosome (EPCs-exo) on proliferation and osteogenic and angiogenic differentiations of adipose-derived stem cells (ADSCs).

METHODS

The adipose tissue and bone marrow of 10 Sprague Dawley rats were harvested. Then the ADSCs and EPCs were isolated and cultured by collagenase digestion method and density gradient centrifugation method, respectively, and identified by flow cytometry. Exo was extracted from the 3rd to 5th generation EPCs using extraction kit, and CD9 and CD81 were detected by Western blot for identification. The three-dimensional printed titanium was modified by ultrasonic acid etching and anodic oxidation to prepare the UAT. The surface characteristics of UAT before and after modification was observed by scanning electron microscopy; UAT was placed in EPCs-exo solutions of different concentrations (100, 200 ng/mL), and the in vitro absorption and release capacity of EPCs-exo was detected by BCA method. Then, UAT was placed in DMEM medium containing different concentrations of EPCs-exo (0, 100, 200 ng/mL), and co-cultured with the 3rd generation ADSCs to construct UAT-ADSCs-exo. Cell morphology by laser confocal microscopy, live/dead cell staining, and cell proliferation were observed to evaluate biocompatibility; alkaline phosphatase (ALP) staining and alizarin red staining, RT-PCR detection of osteogenesis-related genes [osteocalcin (OCN), RUNT-related transcription factor 2 (Runx2), ALP, collagen type 1 (COL-1)] and angiogenesis-related gene [vascular endothelial growth factor (VEGF)], immunofluorescence staining for osteogenesis (OCN)- and angiogenesis (VEGF)-related protein expression were detected to evaluate the effect on the osteogenic and angiogenic differentiation ability of ADSCs.

RESULTS

Scanning electron microscopy showed that micro-nano multilevel composite structures were formed on the surface of UAT. About 77% EPCs-exo was absorbed by UAT within 48 hours, while EPCs-exo absorbed on the surface of UAT showed continuous and stable release within 8 days. The absorption and release amount of 200 ng/mL group were significantly higher than those of 100 ng/mL group ( P<0.05). Biocompatibility test showed that the cells in all concentration groups grew well after culture, and the 200 ng/mL group was better than the other groups, with fully spread cells and abundant pseudopodia, and the cell count and cell activity were significantly higher than those in the other groups ( P<0.05). Compared with the other groups, 200 ng/mL group showed enhanced ALP activity and mineralization ability, increased expressions of osteogenic and angiogenic genes (OCN, Runx2, COL-1, ALP, and VEGF), as well as increased expressions of OCN and VEGF proteins, with significant differences ( P<0.05).

CONCLUSION

EPCs-exo can effectively promote the adhesion, proliferation, and osteogenic and angiogenic differentiation of ADSCs on UAT surface, the effect is the most significant when the concentration is 200 ng/mL.

Long non-coding RNAs and exosomal lncRNAs: Potential functions in lung cancer progression, drug resistance and tumor microenvironment remodeling

Among the different kinds of tumors threatening human life, lung cancer is one that is commonly observed in both males and females. The aggressive behavior of lung cancer and interactions occurring in tumor microenvironment enhances the malignancy of this tumor. The lung tumor cells have demonstrated capacity in developing chemo- and radio-resistance. LncRNAs are a category of non-coding RNAs that do not encode proteins, but their aberrant expression is responsible for tumor development, especially lung cancer. In the present review, we focus on both lncRNAs and exosomal lncRNAs in lung cancer, and their ability in regulating proliferation and metastasis. Cell cycle progression and molecular mechanisms related to lung cancer metastasis such as EMT and MMPs are regulated by lncRNAs. LncRNAs interact with miRNAs, STAT, Wnt, EZH2, PTEN and PI3K/Akt signaling pathways to affect progression of lung cancer cells. LncRNAs demonstrate both tumor-suppressor and tumor-promoting functions in lung cancer. They can be considered as biomarkers in lung cancer and especially exosomal lncRNAs present in body fluids are potential tools for minimally invasive diagnosis. Furthermore, we discuss regulation of lncRNAs by anti-cancer drugs and genetic tools as well as the role of these factors in therapy response of lung cancer cells.

Emerging function and clinical significance of extracellular vesicle noncoding RNAs in lung cancer

Lung cancer (LC) is a commonly diagnosed cancer with an unsatisfactory prognosis. Extracellular vesicles (EVs) are lipid bilayer-delimited particles that mediate cell-cell communication by transporting various biomacromolecules, such as nucleic acids, proteins, and lipids. Noncoding RNAs (ncRNAs), including microRNAs, circular RNAs, and long noncoding RNAs, are important noncoding transcripts that play critical roles in a variety of physiological and pathological processes, especially in cancer. ncRNAs have been verified to be packaged into EVs and transported between LC cells and stromal cells, regulating multiple LC malignant phenotypes, such as proliferation, migration, invasion, epithelial-mesenchymal transition, metastasis, and treatment resistance. Additionally, EVs can be detected in various body fluids and are associated with the stage, grade, and metastasis of LC. Herein, we summarize the biological characteristics and functions of EV ncRNAs in the biological processes of LC, focusing on their potential to serve as diagnostic and prognostic biomarkers of LC as well as their probable role in the clinical treatment of LC. EV ncRNAs provide a new perspective for understanding the mechanism underlying LC pathogenesis and development, which might benefit numerous LC patients in the future.

Emerging role of non-coding RNAs in the regulation of KRAS

The Kirsten ras oncogene KRAS is a member of the small GTPase superfamily participating in the RAS/MAPK pathway. A single amino acid substitution in KRAS gene has been shown to activate the encoded protein resulting in cell transformation. This oncogene is involved in the malignant transformation in several tissues. Notably, numerous non-coding RNAs have been found to interact with KRAS protein. Such interaction results in a wide array of human disorders, particularly cancers. Orilnc1, KIMAT1, SLCO4A1-AS1, LINC01420, KRAS1P, YWHAE, PART1, MALAT1, PCAT-1, lncRNA-NUTF2P3-001 and TP53TG1 are long non-coding RNAs (lncRNAs) whose interactions with KRAS have been verified in the context of cancer. miR-143, miR-96, miR-134 and miR-126 have also been shown to interact with KRAS in different tissues. Finally, circITGA7, circ_GLG1, circFNTA and circ-MEMO1 are examples of circular RNAs (circRNAs) that interact with KRAS. In this review, we describe the interaction between KRAS and lncRNAs, miRNAs and circRNAs, particularly in the context of cancer.

Emerging role of exosomal long non-coding RNAs in lung cancer

BACKGROUND

Lung cancer is one of the most common malignancies worldwide. Also, it is the leading cause of cancer morbidity and mortality in men. Despite advances in lung cancer diagnosis and treatment, novel approaches are strongly needed to promote early diagnosis and effective treatment of lung cancer. Presently, accumulating data reveal that long noncoding RNAs (lncRNAs) are differentially enriched in exosomes and mediate multiple biological processes in lung cancer, suggesting the potential application of exosomal lncRNAs as diagnostic biomarkers and therapeutic targets.

CONCLUSION

In this review, we described the emerging roles of lncRNAs specifically sorted into exosomes in lung cancer. We discussed the current knowledge of the exosomal lncRNA sorting mechanism and highlighted opportunities for exosome-derived lncRNAs as biomarkers in clinical practice. In particular, we systematically summarized the biological functions of exosomal lncRNAs in lung cancer.

The Interaction Between Long Non-Coding RNAs and Cancer-Associated Fibroblasts in Lung Cancer

Despite great advances in research and treatment, lung cancer is still one of the most leading causes of cancer-related deaths worldwide. Evidence is mounting that dynamic communication network in the tumor microenvironment (TME) play an integral role in tumor initiation and development. Cancer-associated fibroblasts (CAFs), which promote tumor growth and metastasis, are the most important stroma component in the tumor microenvironment. Consequently, in-depth identification of relevant molecular mechanisms and biomarkers related to CAFs will increase understanding of tumor development process, which is of great significance for precise treatment of lung cancer. With the development of sequencing technologies such as microarray and next-generation sequencing, lncRNAs without protein-coding ability have been found to act as communicators between tumor cells and CAFs. LncRNAs participate in the activation of normal fibroblasts (NFs) to CAFs. Moreover, activated CAFs can influence the gene expression and secretion characteristics of cells through lncRNAs, enhancing the malignant biological process in tumor cells. In addition, lncRNA-loaded exosomes are considered to be another important form of crosstalk between tumor cells and CAFs. In this review, we focus on the interaction between tumor cells and CAFs mediated by lncRNAs in the lung cancer microenvironment, and discuss the analysis of biological function and molecular mechanism. Furthermore, it contributes to paving a novel direction for the clinical treatment of lung cancer.

KRAS-related long noncoding RNAs in human cancers

KRAS is one of the most widely prevalent proto-oncogenes in human cancers. The constitutively active KRAS oncoprotein contributes to both tumor onset and cancer development by promoting cell proliferation and anchorage-independent growth in a MAPK pathway-dependent manner. The expression of microRNAs (miRNAs) and the KRAS oncogene are known to be dysregulated in various cancers, while long noncoding RNAs (lncRNAs) can act as regulators of the miRNAs targeting KRAS oncogene in different cancers and have gradually become a focus of research in recent years. In this review article, we summarize recent advances in the research on lncRNAs that have sponging effects on KRAS-targeting miRNAs as crucial mediators of KRAS expression in different cell types and organs. A deeper understanding of lncRNA function in KRAS-driven cancers is of major fundamental importance and will provide a valuable clinical tool for the diagnosis, prognosis, and eventual treatment of cancers.

Exosomal miRNAs and lncRNAs: The Modulator Keys of Cancer-Associated Fibroblasts in the Genesis and Progression of Malignant Neoplasms

The tumor microenvironment is made up of a universe of molecular and cellular components that promote or inhibit the development of neoplasms. Among the molecular elements are cytokines, metalloproteinases, proteins, mitochondrial DNA, and nucleic acids, within which the ncRNAs: miRNAs and lncRNAs stand out due to their direct modulating effects on the genesis and progression of various cancers. Regarding cellular elements, the solid tumor microenvironment is made up of tumor cells, healthy adjacent epithelial cells, immune system cells, endothelial cells, and stromal cells, such as cancer-associated fibroblasts, which are capable of generating a modulating communication network with the other components of the tumor microenvironment through, among other mechanisms, the secretion of exosomal vesicles loaded with miRNAs and lncRNAs. These ncRNAs are key pieces in developing neoplasms since they have diverse effects on cancer cells and healthy cells, favoring or negatively regulating protumoral cellular events, such as migration, invasion, proliferation, metastasis, epithelial-mesenchymal transition, and resistance to treatment. Due to the growing number of relevant evidence in recent years, this work focused on reviewing, analyzing, highlighting, and showing the current state of research on exosomal ncRNAs derived from cancer-associated fibroblasts and their effects on different neoplasms. A future perspective on using these ncRNAs as real therapeutic tools in the treatment of cancer patients is also proposed.

MicroRNAs regulating SOX2 in cancer progression and therapy response

The proliferation, metastasis and therapy response of tumour cells are tightly regulated by interaction among various signalling networks. The microRNAs (miRNAs) can bind to 3'-UTR of mRNA and down-regulate expression of target gene. The miRNAs target various molecular pathways in regulating biological events such as apoptosis, differentiation, angiogenesis and migration. The aberrant expression of miRNAs occurs in cancers and they have both tumour-suppressor and tumour-promoting functions. On the contrary, SOX proteins are capable of binding to DNA and regulating gene expression. SOX2 is a well-known member of SOX family that its overexpression in different cancers to ensure progression and stemness. The present review focuses on modulatory impact of miRNAs on SOX2 in affecting growth, migration and therapy response of cancers. The lncRNAs and circRNAs can function as upstream mediators of miRNA/SOX2 axis in cancers. In addition, NF-κB, TNF-α and SOX17 are among other molecular pathways regulating miRNA/SOX2 axis in cancer. Noteworthy, anti-cancer compounds including bufalin and ovatodiolide are suggested to regulate miRNA/SOX2 axis in cancers. The translation of current findings to clinical course can pave the way to effective treatment of cancer patients and improve their prognosis.

New insights into exosome mediated tumor-immune escape: Clinical perspectives and therapeutic strategies

Recent advances in extracellular vesicle biology have uncovered a substantial role in maintaining cell homeostasis in health and disease conditions by mediating intercellular communication, thus catching the scientific community's attention worldwide. Extracellular microvesicles, some called exosomes, functionally transfer biomolecules such as proteins and non-coding RNAs from one cell to another, influencing the local environment's biology. Although numerous advancements have been made in treating cancer patients with immune therapy, controlling the disease remains a challenge in the clinic due to tumor-driven interference with the immune response and inability of immune cells to clear cancer cells from the body. The present review article discusses the recent findings and knowledge gaps related to the role of exosomes derived from tumors and the tumor microenvironment cells in tumor escape from immunosurveillance. Further, we highlight examples where exosomal non-coding RNAs influence immune cells' response within the tumor microenvironment and favor tumor growth and progression. Therefore, exosomes can be used as a therapeutic target for the treatment of human cancers.

Kras-driven intratumoral heterogeneity triggers infiltration of M2 polarized macrophages via the circHIPK3/PTK2 immunosuppressive circuit

Intratumoral heterogeneity in lung cancer is essential for evasion of immune surveillance by tumor cells and establishment of immunosuppression. Gathering data reveal that circular RNAs (circRNAs), play a role in the pathogenesis and progression of lung cancer. Particularly Kras-driven circRNA signaling triggers infiltration of myeloid-associated tumor macrophages in lung tumor microenvironment thus establishing immune deregulation, and immunosuppression but the exact pathogenic mechanism is still unknown. In this study, we investigate the role of oncogenic Kras signaling in circRNA-related immunosuppression and its involvement in tumoral chemoresistance. The expression pattern of circRNAs HIPK3 and PTK2 was determined using quantitative polymerase chain reaction (qPCR) in lung cancer patient samples and cell lines. Apoptosis was analyzed by Annexin V/PI staining and FACS detection. M2 macrophage polarization and MDSC subset analysis (Gr1^-/CD11b^-, Gr1^-/CD11b⁺) were determined by flow cytometry. Tumor growth and metastatic potential were determined in vivo in C57BL/6 mice. Findings reveal intra-epithelial CD163⁺/CD206⁺ M2 macrophages to drive Kras immunosuppressive chemoresistance through myeloid differentiation. In particular, monocytic MDSC subsets Gr1^-/CD11b^-, Gr1^-/CD11b⁺ triggered an M2-dependent immune response, creating an immunosuppressive tumor-promoting network via circHIPK3/PTK2 enrichment. Specifically, upregulation of exosomal cicHIPK3/PTK2 expression prompted Kras-driven intratumoral heterogeneity and guided lymph node metastasis in C57BL/6 mice. Consequent co-inhibition of circPTK2/M2 macrophage signaling suppressed lung tumor growth along with metastatic potential and prolonged survival in vivo. Taken together, these results demonstrate the key role of myeloid-associated macrophages in sustaining lung immunosuppressive neoplasia through circRNA regulation and represent a potential therapeutic target for clinical intervention in metastatic lung cancer.

Exosomal miR-21-5p contributes to ovarian cancer progression by regulating CDK6

Ovarian cancer is a predominant gynecologic malignancy and correlated with high mortality and severe morbidity. Exosomal microRNAs (miRNAs) play crucial roles in various processes during the progression of ovarian cancer, such as cell proliferation, apoptosis, and invasion. However, the function of exosomal miR-21-5p in ovarian cancer is still unknown. Here, we found that miR-21-5p was upregulated in ovarian cancer tissues, plasma exosomes of ovarian cancer patients, and exosomes from ovarian cancer cells. MiR-21-5p was incorporated in the exosomes from the ovarian cancer cells. In addition, 5-ethynyl-2'-deoxyuridine (Edu), a marker of cancer cell proliferation, was enhanced by miR-21-5p mimic while reduced by miR-21-5p inhibitor in ovarian cancer cells. MiR-21-5p mimic could increase, but miR-21-5p inhibitor could decrease the migration and invasion of cancer cells. Ovarian cancer cell apoptosis was induced by miR-21-5p inhibitor. Moreover, miR-21-5p inhibitor could up-regulate the expression of pro-apoptotic cleaved caspase3 and Bax while downregulate the expression of anti-apoptotic Bcl2 in the cells. Exosomal miR-21-5p inhibited the expression of cyclin-dependent kinase 6 (CDK6) by targeting its 3'-untranslated region (3'-UTR) at both the mRNA and protein levels. Tumorigenicity analysis in nude mice revealed that exosomal miR-21-5p could increase tumor volume, size, and weight of ovarian cancer in vivo. Besides, miR-21-5p targeted CDK6 in tumor tissues of nude mice. In conclusion, exosomal miR-21-5p contributes to the progression of ovarian cancer by regulating CDK6. Our findings will provide novel insights into the mechanism of exosomal miR-21-5p in the development of ovarian cancer. Exosomal miR-21-5p may serve as a potential target for the therapy of ovarian cancer.

Noncoding RNAs in the Interplay between Tumor Cells and Cancer-Associated Fibroblasts: Signals to Catch and Targets to Hit

Simple Summary

Cancer aggressiveness is the result of a proficient bidirectional interaction between tumor and stromal cells within the tumor microenvironment, among which a major role is played by the so-called cancer-associated fibroblasts. Upon such interplay, both cancer cells and fibroblasts are reprogrammed to sustain malignancy, with changes in the repertoire of noncoding RNAs, mainly microRNAs and long noncoding RNAs. Such molecules are also exchanged between the two cell types through extracellular vesicles. In this review, we summarize the current knowledge of microRNAs and long noncoding RNAs that act intracellularly or extracellularly to sustain tumor-stroma interplay. We also provide our view regarding the possible clinical utility of such noncoding RNAs as therapeutic target/tools or biomarkers to predict patient outcome or response to specific treatments.

Abstract

Cancer development and progression are not solely cell-autonomous and genetically driven processes. Dynamic interaction of cancer cells with the surrounding microenvironment, intended as the chemical/physical conditions as well as the mixture of non-neoplastic cells of the tumor niche, drive epigenetic changes that are pivotal for the acquisition of malignant traits. Cancer-associated fibroblasts (CAF), namely fibroblasts that, corrupted by cancer cells, acquire a myofibroblast-like reactive phenotype, are able to sustain tumor features by the secretion of soluble paracrine signals and the delivery extracellular vesicles. In such diabolic liaison, a major role has been ascribed to noncoding RNAs. Defined as RNAs that are functional though not being translated into proteins, noncoding RNAs predominantly act as regulators of gene expression at both the transcriptional and post-transcriptional levels. In this review, we summarize the current knowledge of microRNAs and long noncoding RNAs that act intracellularly in either CAFs or cancer cells to sustain tumor-stroma interplay. We also report on the major role of extracellular noncoding RNAs that are bidirectionally transferred between either cell type. Upon presenting a comprehensive view of the existing literature, we provide our critical opinion regarding the possible clinical utility of tumor-stroma related noncoding RNAs as therapeutic target/tools or prognostic/predictive biomarkers.

The promising role of noncoding RNAs in cancer-associated fibroblasts: an overview of current status and future perspectives

As the most important component of the stromal cell population in the tumor microenvironment (TME), cancer-associated fibroblasts (CAFs) are crucial players in tumor initiation and progression. The interaction between CAFs and tumor cells, as well as the resulting effect, is much greater than initially expected. Numerous studies have shown that noncoding RNAs (ncRNAs) play an irreplaceable role in this interplay, and related evidence continues to emerge and advance. Under the action of ncRNAs, normal fibroblasts are directly or indirectly activated into CAFs, and their metabolic characteristics are changed; thus, CAFs can more effectively promote tumor progression. Moreover, via ncRNAs, activated CAFs can affect the gene expression and secretory characteristics of cells, alter the TME and enhance malignant biological processes in tumor cells to contribute to tumor promotion. Previously, ncRNA dysregulation was considered the main mechanism by which ncRNAs participate in the crosstalk between CAFs and tumor cells. Recently, however, exosomes containing ncRNAs have been identified as another vital mode of interaction between these two types of cells, with a more direct and clear function. Gaining an in-depth understanding of ncRNAs in CAFs and the complex regulatory network connecting CAFs with tumor cells might help us to establish more effective and safer approaches for cancer therapies targeting ncRNAs and CAFs and offer new hope for cancer patients.

Treg-dependent immunosuppression triggers effector T cell dysfunction via the STING/ILC2 axis

Lung cancer remains the leading cause of cancer-related deaths and despite extensive research, the survival rate of lung cancer patients remains significantly low. Recent data reveal that aberrant Kras signaling drives regulatory T cells (Tregs) present in lung tumor microenvironment to establish immune deregulation and immunosuppression but the exact pathogenic mechanism is still unknown. In this study, we investigate the role of oncogenic Kras in Treg-related immunosuppression and its involvement in tumor-associated metabolic reprogramming. Findings reveal Tregs to prompt GATA3/NOS2-related immunosuppression via STING inhibition which triggers a decline in CD4⁺ T infiltration, and a subsequent increase in lung metastatic burden. Enhanced Treg expression was also associated with low T/MDSC ratio through restriction of CD8⁺CD44⁺CD62L^- T effector cells, contributing to a tumor-promoting status. Specifically, TIM3⁺/LAG3⁺ Tregs prompted Kras-related immunosuppressive chemoresistance and were associated with T cell dysfunction. This Treg-dependent immunosuppression correlated with CD8 T cell exhaustion phenotype and ILC2 augmentation in mice. Moreover, enhanced Treg expression promoted activation-induced cell death (AICD) of T lymphocytes and guided lymph node metastasis in vivo. Overall, these findings demonstrate the multifaceted roles of Tregs in sustaining lung immunosuppressive neoplasia through tumor microenvironment remodeling and provide new opportunities for effective metastasis inhibition, especially in chemoresistant tumors.

The landscape of long non-coding RNAs in tumor stroma

AIMS

Long non-coding RNAs (lncRNAs) are associated with cancer development, while their relationship with the cancer-associated stromal components remains poorly understood. In this review, we performed a broad description of the functional landscape of stroma-associated lncRNAs in various cancers and their roles in regulating the tumor-stroma crosstalk.

MATERIALS AND METHODS

We carried out a systematic literature review of PubMed, Scopus, Medline, Bentham, and EMBASE (Elsevier) databases by using the keywords "LncRNAs in cancer," "LncRNAs in tumor stroma," "stroma," "cancer-associated stroma," "stroma in the tumor microenvironment," "tumor-stroma crosstalk," "drug resistance of stroma," and "stroma in immunosuppression" till July 2020. We collected the latest articles addressing the biological functions of stroma-associated lncRNAs in cancer.

KEY FINDINGS

These articles reported that dysregulated stroma-associated lncRNAs play significant roles in modulating the tumor microenvironment (TME) by the regulation of tumor-stroma crosstalk, epithelial to mesenchymal transition (EMT), endothelial to mesenchymal transition (EndMT), extracellular matrix (ECM) turnover, and tumor immunity.

SIGNIFICANCE

The tumor stroma is a substantial portion of the TME, and the dysregulation of tumor stroma-associated lncRNAs significantly contributes to cancer initiation, progression, angiogenesis, immune evasion, metastasis, and drug resistance. Thus, stroma-associated lncRNAs could be potentially useful targets for cancer therapy.