Current perspectives on the crosstalk between lung cancer stem cells and cancer-associated fibroblasts

Biomimetic Cell Membrane-Coated Nanoparticles for Cancer Theranostics

Nanoparticles can enhance drugs accumulating at the tumor site and hold tremendous promise for achieving effective tumor treatment. However, due to the complexity of cancer heterogeneity and suppressive tumor microenvironment, the delivery of traditional nanoparticles has poor infiltration and off-target effects, making it difficult to control the drug release rate and causing off-target toxicity. In recent years, cell membrane-coated biomimetic nanoparticles have been developed, which have both the natural characteristics of biomembranes and the physical characteristics of traditional nanoparticles, thus improving the homologous targeting ability of nanoparticles to tumor cells and better biocompatibility. In this paper, we reviewed the application of single cell membrane and hybrid cell membrane-coated biomimetic nanoparticles in the integration for tumor diagnosis and treatment. We talked about the preparation methods of cell membrane-coated nanoparticles, the targeting mechanisms, and the effects of imaging and therapeutic outcomes of different cell membrane-coated biomimetic nanoparticles in detail. Finally, we discussed the existing problems and prospects of cell membrane-coated biomimetic nanomaterials.

Exosomal lncRNA ROR1-AS1 from cancer-associated fibroblasts inhibits ferroptosis of lung cancer cells through the IGF2BP1/SLC7A11 signal axis

BACKGROUND

Targeting ferroptosis is a potential strategy for cancer treatment. Activated cancer-associated fibroblasts (CAFs) can affect the progression of lung cancer through exosomes. This study investigated the mechanism by which exosomal lncRNA ROR1-AS1 derived from CAFs affects ferroptosis of lung cancer cells.

METHODS

CAFs were identified by western blot and immunofluorescence. Exosomes derived from CAFs (CAF-exo) were analyzed by transmission electron microscope, nanoparticle tracking analysis and western blot. The expression levels of ROR1-AS1, IGF2BP1 and SLC7A11 in lung cancer were analyzed by bioinformatics analysis and detected by qPCR and western blot. The lung cancer cells were treated with Erastin and/or CAF-exo, then cell viability was detected by cell counting kit-8, and the ferroptosis-related indicators were detected by corresponding kits. The relationship between IGF2BP1 and ROR1-AS1 or SLC7A11 was determined by RNA pull down and RNA immunoprecipitation, and their effects on cell ferroptosis were confirmed by rescue experiments. Xenotransplantation experiment was used to determine the effect of CAF-exo on tumor growth and ferroptosis in vivo. Immunohistochemistry was used to identify the Ki-67 and 4-HNE expression.

RESULTS

ROR1-AS1, IGF2BP1 and SLC7A11 were upregulated in lung cancer and indicated poor prognosis. LncRNA ROR1-AS1 increased the stability of SLC7A11 mRNA by interacting with IGF2BP1. Exosomal ROR1-AS1 from CAFs inhibited ferroptosis of lung cancer cells in vitro and in vivo. The effect of ROR1-AS1 overexpression or IGF2BP1 overexpression on ferroptosis of lung cancer cells was partially reversed by IGF2BP1 silencing or SLC7A11 inhibition.

CONCLUSIONS

CAFs secrete exosomal ROR1-AS1 to promote the expression of SLC7A11 by interacting with IGF2BP1, thereby inhibiting ferroptosis of lung cancer cells.

Cancer-associated fibroblasts and its derived exosomes: a new perspective for reshaping the tumor microenvironment

Cancer-associated fibroblasts (CAFs) are the most abundant stromal cells within the tumor microenvironment (TME). They extensively communicate with the other cells. Exosome-packed bioactive molecules derived from CAFs can reshape the TME by interacting with other cells and the extracellular matrix, which adds a new perspective for their clinical application in tumor targeted therapy. An in-depth understanding of the biological characteristics of CAF-derived exosomes (CDEs) is critical for depicting the detailed landscape of the TME and developing tailored therapeutic strategies for cancer treatment. In this review, we have summarized the functional roles of CAFs in the TME, particularly focusing on the extensive communication mediated by CDEs that contain biological molecules such as miRNAs, proteins, metabolites, and other components. In addition, we have also highlighted the prospects for diagnostic and therapeutic applications based on CDEs, which could guide the future development of exosome-targeted anti-tumor drugs.

Neural induction drives body axis formation during embryogenesis, but a neural induction-like process drives tumorigenesis in postnatal animals

Characterization of cancer cells and neural stem cells indicates that tumorigenicity and pluripotency are coupled cell properties determined by neural stemness, and tumorigenesis represents a process of progressive loss of original cell identity and gain of neural stemness. This reminds of a most fundamental process required for the development of the nervous system and body axis during embryogenesis, i.e., embryonic neural induction. Neural induction is that, in response to extracellular signals that are secreted by the Spemann-Mangold organizer in amphibians or the node in mammals and inhibit epidermal fate in ectoderm, the ectodermal cells lose their epidermal fate and assume the neural default fate and consequently, turn into neuroectodermal cells. They further differentiate into the nervous system and also some non-neural cells via interaction with adjacent tissues. Failure in neural induction leads to failure of embryogenesis, and ectopic neural induction due to ectopic organizer or node activity or activation of embryonic neural genes causes a formation of secondary body axis or a conjoined twin. During tumorigenesis, cells progressively lose their original cell identity and gain of neural stemness, and consequently, gain of tumorigenicity and pluripotency, due to various intra-/extracellular insults in cells of a postnatal animal. Tumorigenic cells can be induced to differentiation into normal cells and integrate into normal embryonic development within an embryo. However, they form tumors and cannot integrate into animal tissues/organs in a postnatal animal because of lack of embryonic inducing signals. Combination of studies of developmental and cancer biology indicates that neural induction drives embryogenesis in gastrulating embryos but a similar process drives tumorigenesis in a postnatal animal. Tumorigenicity is by nature the manifestation of aberrant occurrence of pluripotent state in a postnatal animal. Pluripotency and tumorigenicity are both but different manifestations of neural stemness in pre- and postnatal stages of animal life, respectively. Based on these findings, I discuss about some confusion in cancer research, propose to distinguish the causality and associations and discriminate causal and supporting factors involved in tumorigenesis, and suggest revisiting the focus of cancer research.

CPSF4 promotes tumor-initiating phenotype by enhancing VEGF/NRP2/TAZ signaling in lung cancer

Lung cancer is the leading cause of malignant tumor-related deaths worldwide. The presence of tumor-initiating cells in lung cancer leads to tumor recurrence, metastasis, and resistance to conventional treatment. Cleavage and polyadenylation specificity factor 4 (CPSF4) activation in tumor cells contributes to the poor prognosis of lung cancer. However, the precise biological functions and molecular mechanisms of CPSF4 in the regulation of tumor-initiating cells remain unclear. We demonstrated that CPSF4 promotes tumor-initiating phenotype and confers chemoresistance to paclitaxel both in vitro and in vivo. Mechanistically, we showed that CPSF4 binds to the promoters of vascular endothelial growth factor (VEGF) and neuropilin-2 (NRP2) and activated their transcription. In addition, we showed that CPSF4/VEGF/NRP2-mediated tumor-initiating phenotype and chemoresistance through TAZ induction. Furthermore, analysis of clinical data revealed that lung cancer patients with high CPSF4 expression exhibit high expression levels of VEGF, NRP2, and TAZ and that expression of these proteins are positively correlated with poor prognosis. Importantly, selective inhibition of VEGF, NRP2, or TAZ markedly suppressed CPSF4-mediated tumor-initiating phenotype and chemoresistance. Our findings reveal the mechanism of CPSF4 modulating tumor-initiating phenotype and chemoresistance in lung cancer and indicate that the CPSF4-VEGF-NRP2-TAZ signaling pathway may be a prognosis marker and therapeutic target in lung cancer.

Chronic intermittent hypoxia promoted lung cancer stem cell-like properties via enhancing Bach1 expression

BACKGROUND

An adverse role for obstructive sleep apnea (OSA) in cancer aggressiveness and mortality has recently emerged from clinical and animal studies, and the reasons have not been fully determined. Cancer stem cells (CSCs) are regarded as the main cause of carcinoma metastasis. So far, the relationship between OSA and lung CSCs has not been explored.

METHOD

In the present study, we established an orthotopic mouse model of primary lung cancer and utilized chronic intermittent hypoxia (CIH) exposure to mimic OSA status.

RESULTS

We observed that CIH endows lung cancer with greater metastatic potential, evidenced by increased tumor growth, tumor seeding, and upregulated CSC-related gene expression in the lungs. Notably, the transcription factor BTB and CNC homology 1 (Bach1), a key factor in responding to conditions of oxidative stress, is increased in lung cancer after CIH exposure in vitro and in vivo. Meanwhile, exposing lung cancer cells to CIH promoted cell proliferation, clonal diversity, induced stem-like cell marker expression, and gave rise to CSCs at a relatively higher frequency. Furthermore, the increase of mitochondrial ROS (mtROS) and CSC-marker expression induced by CIH exposure was abolished in Bach1 shRNA-treated lung cancer cells.

CONCLUSIONS

Our results indicated that CIH promoted lung CSC-like properties by activating mtROS, which was partially mediated by Bach1.

The CXCL12 Crossroads in Cancer Stem Cells and Their Niche

Simple Summary

CXCL12 and its receptors have been extensively studied in cancer, including their influence on cancer stem cells (CSCs) and their niche. This intensive research has led to a better understanding of the crosstalk between CXCL12 and CSCs, which has aided in designing several drugs that are currently being tested in clinical trials. However, a comprehensive review has not been published to date. The aim of this review is to provide an overview on how CXCL12 axes are involved in the regulation and maintenance of CSCs, their presence and influence at different cellular levels within the CSC niche, and the current state-of-the-art of therapeutic approaches aimed to target the CXCL12 crossroads.

Abstract

Cancer stem cells (CSCs) are defined as a subpopulation of “stem”-like cells within the tumor with unique characteristics that allow them to maintain tumor growth, escape standard anti-tumor therapies and drive subsequent repopulation of the tumor. This is the result of their intrinsic “stem”-like features and the strong driving influence of the CSC niche, a subcompartment within the tumor microenvironment that includes a diverse group of cells focused on maintaining and supporting the CSC. CXCL12 is a chemokine that plays a crucial role in hematopoietic stem cell support and has been extensively reported to be involved in several cancer-related processes. In this review, we will provide the latest evidence about the interactions between CSC niche-derived CXCL12 and its receptors—CXCR4 and CXCR7—present on CSC populations across different tumor entities. The interactions facilitated by CXCL12/CXCR4/CXCR7 axes seem to be strongly linked to CSC “stem”-like features, tumor progression, and metastasis promotion. Altogether, this suggests a role for CXCL12 and its receptors in the maintenance of CSCs and the components of their niche. Moreover, we will also provide an update of the therapeutic options being currently tested to disrupt the CXCL12 axes in order to target, directly or indirectly, the CSC subpopulation.

Tumor microenvironment pathways: Cross regulation in breast cancer metastasis

The tumor microenvironment (TME) is heterogeneous and contains a multiple cell population with surrounded immune cells, which plays a major role in regulating metastasis. The multifunctional pathways, Hedgehog (Hh), Wnt, Notch, and NF-kB, cross-regulates metastasis in breast cancer. This review presents substantial evidence for cross-regulation of TME components and signaling pathways, which makes breast TME more heterogeneous and complex, promoting breast cancer progression and metastasis as a highly aggressive form. We discoursed the importance of stromal and immune cells as well as their crosstalk in bridging the metastasis. We also discussed the role of Hh and Notch pathways in the intervention between breast cancer cells and macrophages to support TME; Notch signaling in the bidirectional communication between cancer cells and components of TME; Wnt signal pathway in controlling the factors responsible for EMT and NF-κB pathway in the regulation of genes controlling the inflammatory response. We also present the role of exosomes and their miRNAs in the cross-regulation of TME cells as well as pathways in the reprogramming of breast TME to support metastasis. Finally, we examined and discussed the targeted small molecule inhibitors and natural compounds targeting developmental pathways and proposed small molecule natural compounds as potential therapeutics of TME based on the multitargeting ability. In conclusion, the understanding of the molecular basis of the cross-regulation of TME pathways and their inhibitors helps identify molecular targets for rational drug discovery to treat breast cancers.

Cancer stem cell secretome in the tumor microenvironment: a key point for an effective personalized cancer treatment

Cancer stem cells (CSCs) represent a tumor subpopulation responsible for tumor metastasis and resistance to chemo- and radiotherapy, ultimately leading to tumor relapse. As a consequence, the detection and eradication of this cell subpopulation represent a current challenge in oncology medicine. CSC phenotype is dependent on the tumor microenvironment (TME), which involves stem and differentiated tumor cells, as well as different cell types, such as mesenchymal stem cells, endothelial cells, fibroblasts and cells of the immune system, in addition to the extracellular matrix (ECM), different in composition to the ECM in healthy tissues. CSCs regulate multiple cancer hallmarks through the interaction with cells and ECM in their environment by secreting extracellular vesicles including exosomes, and soluble factors such as interleukins, cytokines, growth factors and other metabolites to the TME. Through these factors, CSCs generate and activate their own tumor niche by recruiting stromal cells and modulate angiogenesis, metastasis, resistance to antitumor treatments and their own maintenance by the secretion of different factors such as IL-6, VEGF and TGF-ß. Due to the strong influence of the CSC secretome on disease development, the new antitumor therapies focus on targeting these communication networks to eradicate the tumor and prevent metastasis, tumor relapse and drug resistance. This review summarizes for the first time the main components of the CSC secretome and how they mediate different tumor processes. Lastly, the relevance of the CSC secretome in the development of more precise and personalized antitumor therapies is discussed.

Dual inhibition of HDAC and tyrosine kinase signaling pathways with CUDC-907 attenuates TGFβ1 induced lung and tumor fibrosis

TGFβ1 signaling is a critical driver of collagen accumulation in pulmonary fibrotic diseases and a well-characterized regulator of cancer associated fibroblasts (CAF) activation in lung cancer. Myofibroblasts induced by TGFβ1 and other factors are key players in the pathogenesis of lung fibrosis and tumor. Tremendous attention has been gained to targeting myofibroblasts in order to inhibit the progression of fibrosis and myofibroblast-induced tumor progression and metastasis. Here we determined the therapeutic efficacy of simultaneously targeting PI3K and HDAC pathways in lung myofibroblasts and CAF with a single agent and to evaluate biomarkers of treatment response. CUDC-907 is a first-in-class compound, functioning as a dual inhibitor of HDACs and PI3K/AKT pathway. We investigated its effects in counteracting the activity of TGFβ1-induced myofibroblasts/CAF in regard to cell proliferation, migration, invasion, apoptosis in vitro antifibrosis efficiency in vivo. We found that CUDC-907 inhibited myofibroblasts/CAF cell proliferation, migration and apoptosis in a dose-dependent manner and caused cell cycle arrest at G1-S phase. CUDC-907 not only inhibited myofibroblasts markers expression, but also significantly inhibited the phosphorylation level of AKT, mTOR, Smad2/3, and promoted acetylation of histones. Furthermore, the observed inhibitory effect was also confirmed in bleomycin-induced mice lung fibrosis and nude mouse transplanted tumor model. Overall, these data suggest that dual inhibition of HDAC and the tyrosine kinase signaling pathways with CUDC-907 is a promising treatment strategy for TGFβ1-induced lung and tumor fibrosis.

Life style factors, tumor cell plasticity and cancer stem cells

Cancers are heterogeneous tissues and a layer of heterogeneity is determined by the presence of cells showing stemness traits, known as cancer stem cells (CSCs). Evidence indicates that CSCs are important players in tumor development, progression and relapse. Oncogenic transformation of normal stem cells can give rise to CSCs, but CSCs can also originate from de-differentiation of bulk tumor cells. Thus, factors promoting the increase of normal stem cell pools or stimulating the acquisition of stemness features by tumor cells can have serious consequences on cancer origin and progression. In this review, we will first give an overview of the CSC model of cancer development and we will then discuss the role of life style factors, such as high caloric diet, alcohol drinking and smoking, on the widening of stem cell pools and the induction of CSC features in tumors. Finally, we will discuss some healthy life style factors that can help to prevent cancer.

The Cancer Stem Cell in Hepatocellular Carcinoma

The recognition of intra-tumoral cellular heterogeneity has given way to the concept of the cancer stem cell (CSC). According to this concept, CSCs are able to self-renew and differentiate into all of the cancer cell lineages present within the tumor, placing the CSC at the top of a hierarchical tree. The observation that these cells—in contrast to bulk tumor cells—are able to exclusively initiate new tumors, initiate metastatic spread and resist chemotherapy implies that CSCs are solely responsible for tumor recurrence and should be therapeutically targeted. Toward this end, dissecting and understanding the biology of CSCs should translate into new clinical therapeutic approaches. In this article, we review the CSC concept in cancer, with a special focus on hepatocellular carcinoma.

Exosome and Secretion: Action On?

Originally treated as part of a cellular waste, extracellular vesicles (EVs) are being shown to possess a vast variety of functions, of which exosome is the most studied one. Most cells, such as tumor cells, immunocytes, and fibroblasts can secrete exosomes, especially under certain stresses the amount is much higher, and the contents of exosome represent the status of the donor cells and the tumor microenvironment. As crucial transporters for cells' content exchange, much attention has been raised in the utilities of exosomes to suppress immune response, and to modify a microenvironment favorable for cancer progression. Exosomal immune checkpoints, such as programmed cell death ligand 1 (PD-L1), contribute to immunosuppression and are associated with anti-PD-1 response. Many forms of soluble immune checkpoint receptors have also been shown to influence efficacy mediated by their therapeutic antibodies. Therefore, targeting pro-tumorous exosomes may achieve antitumor effect supplementary to existing therapies. Exosome, itself natural liposome-like structure, allows it to be a potential drug delivery tool.

Itraconazole Alters the Stem Cell Characteristics of A549 and NCI-H460 Human Lung Cancer Cells by Suppressing Wnt Signaling

Background

Cancer stem cells (CSCs) behave as their malignant counterparts, but persist after treatment, and possess properties that allow them to interact with their environment. Itraconazole, an antifungal agent, also has a role in suppressing tumor progression, but its effects in regulating tumor cell stemness remain unclear. This study aimed to evaluate the effects of itraconazole on A549 and NCI-H460 human lung cancer cell stemness in vitro.

Material/Methods

A549 and NCI-H460 human lung cancer cells and BEAS-2B normal bronchial epithelial cells were cultured with and without itraconazole. Cell viability was evaluated. The expression of stem cell markers, CD133, ATP binding cassette subfamily G member 2 (ABCG2), and aldehyde dehydrogenase 1 (ALDH1), were measured by Western blot and quantitative real-time polymerase chain reaction (qRT-PCR). Sphere-forming cells were evaluated in vitro.

Results

Itraconazole reduced the expression of stemness molecules CD133, ABCG2, and ALDH1 in A549 and NCI-H460 human lung cancer cells, and the numbers of sphere-forming cells were reduced. However, itraconazole had little effect on cell viability but enhanced the chemosensitivity of A549 and NCI-H460 cells. Itraconazole inhibited Wnt signaling. Re-activation of Wnt signaling restored itraconazole-mediated inhibition on A549 and NCI-H460 cell stemness.

Conclusions

Itraconazole altered the stemness characteristics of A549 and NCI-H460 human lung cancer cells by suppressing Wnt signaling but did not affect cell viability.

Generation and Characterization of Fibroblast-Specific Basigin Knockout Mice

Basigin is a well-known extracellular stimulator of fibroblasts and may confer resistance to apoptosis of fibroblasts in vitro under some pathological status, but its exact function in fibroblasts and the underlying mechanism remain poorly understood. The systematic Basigin gene knockout leads to the perinatal lethality of mice, which limits the delineation of its function in vivo. In this study, we generated a fibroblast-specific Basigin knock-out mouse model and demonstrated the successful deletion of Basigin in fibroblasts. The fibroblast-specific deletion of Basigin did not influence the growth, fertility and the general condition of the mice. No obvious differences were found in the size, morphology, and histological structure of the major organs, including heart, liver, spleen, lung and kidney, between the knockout mice and the control mice. The deletion of Basigin in fibroblasts did not induce apoptosis in the tissues of the major organs. These results provide the first evidence that the fibroblast-specific Basigin knock-out mice could be a useful tool for exploring the function of Basigin in fibroblasts in vivo.

A versatile polyion complex can intelligently respond to a tumor microenvironment to eliminate tumor stem cells for enhanced lung cancer targeted therapy

A versatile polyion complex was fabricated which could response to tumor microenvironment and possess remarkable tumor penetrating capability with elevated antitumor activity for LCSCs elimination in vivo.

The Potential Roles of Extracellular Vesicles in Cigarette Smoke-Associated Diseases

Cigarette smoke contains more than 4,500 chemicals; most of which are highly reactive free radicals, which induce proinflammatory and carcinogenic reactions. Numerous efforts have focused extensively on the role of cigarette smoking as a cause of many diseases. Extracellular vesicles and exosomes have recently received increasing interest for their diagnostic and therapeutic roles in many diseases. However, research done on the role of extracellular vesicles and exosomes on cigarette smoke-induced chronic disease is still in its infancy. In this review, we summarize the recently addressed roles of extracellular vesicles and exosomes in the pathogenesis of cigarette smoke-related diseases, such as chronic obstructive pulmonary disease, cardiovascular disease, lung cancer, and oral cancer. Moreover, their potential utilization and future prospects as diagnostic biomarkers for cigarette smoke-related diseases are described.

The Crosstalk between Cancer Stem Cells and Microenvironment Is Critical for Solid Tumor Progression: The Significant Contribution of Extracellular Vesicles

Several evidences nowadays demonstrated the critical role of the microenvironment in regulating cancer stem cells and their involvement in tumor progression. Extracellular vesicles (EVs) are considered as one of the most effective vehicles of information among cells. Accordingly, a number of studies led to the recognition of stem cell-associated EVs as new complexes able to contribute to cell fate determination of either normal or tumor cells. In this review, we aim to highlight an existing bidirectional role of EV-mediated communication—from cancer stem cells to microenvironment and also from microenvironment to cancer stem cells—in the most widespread solid cancers as prostate, breast, lung, and colon tumors.