Differential glycosylation of collagen modulates lung cancer stem cell subsets through β1 integrin-mediated interactions

Integrin signaling in tumor biology: mechanisms of intercellular crosstalk and emerging targeted therapies

Integrins, a family of transmembrane cell adhesion receptors, mediate intercellular and cell-extracellular matrix crosstalk via outside-in and inside-out signaling pathways. Integrins, categorized into 24 distinct combinations of α and β subunits, exhibit tissue-specific expression and perform unique or overlapping roles in physiological and pathophysiological processes. These roles encompass embryonic angiogenesis, tissue repair, and the modulation of tumor cell angiogenesis, progression, invasion, and metastasis. Notably, integrins are significant contributors to tumor development, offering valuable insights into the potential of integrin-targeted diagnostics and therapeutics. Currently, there are various preclinical and clinical trials aiming to harness integrin antagonists that are safe, efficacious, and exhibit low toxicity. Owing to the functional redundancy across integrin types and the complexity of the mechanisms of integrin-mediated multiple key processes associated with tumor biology, challenges exist that impede advancements in integrin-targeted therapy. Nevertheless, innovative strategies focused on integrin modulation represent significant breakthroughs for improving patient care and promoting comprehensive insights into the underlying mechanisms of tumor biology. This review elucidates the impact of integrins on three distinct cell types in multiple key processes associated with tumor biology and explores the emerging integrin-targeted therapeutic approaches for the treatment of tumors, which will provide ideas for optimal therapeutic approaches in the future.

Spiro-Ometad As A Promising Substrate In Biomedical Devices

Bioactive films composed of Spiro-OMeTAD, a conductive molecular material (CMM), in combination with collagen have been manufactured and characterised for the first time. In-vitro cellular testing demonstrated the non-cytotoxicity of the doped Spiro-OMeTAD /Collagen films, opening the way for implantable or wearable medical devices and biosensors based on molecular materials.

A Niche-Based Perspective to Stem and Cancer Stem Cells of the Lung

Lungs carry the principle function for the conduction and exchange of air through the primary, secondary, tertiary bronchi, bronchioles, and alveoli, resulting in the exchange of oxygen to carbon dioxide within the human tissues. Lung stem and progenitor cells enable differentiation of parenchymal and stromal elements and provide homeostasis and regeneration in the microenvironment against pulmonary diseases. Tumor-initiating cancer cells (TICs) refer to a subpopulation named as cancer stem cells (CSCs) of lung cancer exhibiting high self-renewal and proliferation capacity by Notch, Hippo, Hedgehog, and Wnt signaling pathways that leads to tumor development or recurrence. Lung cancer stem cells (LCSCs) are characterized by distinct genotypic or phenotypic alterations compared to healthy lung stem cells (LSCs) that provide a potential target to treat lung cancer. Therefore, understanding the cascades responsible for the transformation of healthy to CSCs is essential to develop new targeted therapy approaches. In this chapter, we precisely highlight the latest researches on LSCs and CSCs, key signaling mechanisms within the perspective of novel targeted therapy strategies.

Integrins in cancer stem cells

Integrins are a class of adhesion receptors on cell membranes, consisting of α and β subunits. By binding to the extracellular matrix, integrins activate intracellular signaling pathways, participating in every step of cancer initiation and progression. Tumor stem cells possess self-renewal and self-differentiation abilities, along with strong tumorigenic potential. In this review, we discussed the role of integrins in cancer, with a focus on their impact on tumor stem cells and tumor stemness. This will aid in targeting tumor stem cells as a therapeutic approach, leading to the exploration of novel cancer treatment strategies.

Epithelial-mesenchymal plasticity in cancer: signaling pathways and therapeutic targets

Currently, cancer is still a leading cause of human death globally. Tumor deterioration comprises multiple events including metastasis, therapeutic resistance and immune evasion, all of which are tightly related to the phenotypic plasticity especially epithelial-mesenchymal plasticity (EMP). Tumor cells with EMP are manifest in three states as epithelial-mesenchymal transition (EMT), partial EMT, and mesenchymal-epithelial transition, which orchestrate the phenotypic switch and heterogeneity of tumor cells via transcriptional regulation and a series of signaling pathways, including transforming growth factor-β, Wnt/β-catenin, and Notch. However, due to the complicated nature of EMP, the diverse process of EMP is still not fully understood. In this review, we systematically conclude the biological background, regulating mechanisms of EMP as well as the role of EMP in therapy response. We also summarize a range of small molecule inhibitors, immune-related therapeutic approaches, and combination therapies that have been developed to target EMP for the outstanding role of EMP-driven tumor deterioration. Additionally, we explore the potential technique for EMP-based tumor mechanistic investigation and therapeutic research, which may burst vigorous prospects. Overall, we elucidate the multifaceted aspects of EMP in tumor progression and suggest a promising direction of cancer treatment based on targeting EMP.

Cancer stem cells: advances in knowledge and implications for cancer therapy

Cancer stem cells (CSCs), a small subset of cells in tumors that are characterized by self-renewal and continuous proliferation, lead to tumorigenesis, metastasis, and maintain tumor heterogeneity. Cancer continues to be a significant global disease burden. In the past, surgery, radiotherapy, and chemotherapy were the main cancer treatments. The technology of cancer treatments continues to develop and advance, and the emergence of targeted therapy, and immunotherapy provides more options for patients to a certain extent. However, the limitations of efficacy and treatment resistance are still inevitable. Our review begins with a brief introduction of the historical discoveries, original hypotheses, and pathways that regulate CSCs, such as WNT/β-Catenin, hedgehog, Notch, NF-κB, JAK/STAT, TGF-β, PI3K/AKT, PPAR pathway, and their crosstalk. We focus on the role of CSCs in various therapeutic outcomes and resistance, including how the treatments affect the content of CSCs and the alteration of related molecules, CSCs-mediated therapeutic resistance, and the clinical value of targeting CSCs in patients with refractory, progressed or advanced tumors. In summary, CSCs affect therapeutic efficacy, and the treatment method of targeting CSCs is still difficult to determine. Clarifying regulatory mechanisms and targeting biomarkers of CSCs is currently the mainstream idea.

Glycosylation Modulates the Structure and Functions of Collagen: A Review

Collagens are fundamental constituents of the extracellular matrix and are the most abundant proteins in mammals. Collagens belong to the family of fibrous or fiber-forming proteins that self-assemble into fibrils that define their mechanical properties and biological functions. Up to now, 28 members of the collagen superfamily have been recognized. Collagen biosynthesis occurs in the endoplasmic reticulum, where specific post-translational modification-glycosylation-is also carried out. The glycosylation of collagens is very specific and adds β-d-galactopyranose and β-d-Glcp-(1→2)-d-Galp disaccharide through β-O-linkage to hydroxylysine. Several glycosyltransferases, namely COLGALT1, COLGALT2, LH3, and PGGHG glucosidase, were associated the with glycosylation of collagens, and recently, the crystal structure of LH3 has been solved. Although not fully understood, it is clear that the glycosylation of collagens influences collagen secretion and the alignment of collagen fibrils. A growing body of evidence also associates the glycosylation of collagen with its functions and various human diseases. Recent progress in understanding collagen glycosylation allows for the exploitation of its therapeutic potential and the discovery of new agents. This review will discuss the relevant contributions to understanding the glycosylation of collagens. Then, glycosyltransferases involved in collagen glycosylation, their structure, and catalytic mechanism will be surveyed. Furthermore, the involvement of glycosylation in collagen functions and collagen glycosylation-related diseases will be discussed.

Tumor Microenvironment: A Niche for Cancer Stem Cell Immunotherapy

Tumorigenic Cancer Stem Cells (CSCs), often called tumor-initiating cells (TICs), represent a unique subset of cells within the tumor milieu. They stand apart from the bulk of tumor cells due to their exceptional self-renewal, metastatic, and differentiation capabilities. Despite significant progress in classifying CSCs, these cells remain notably resilient to conventional radiotherapy and chemotherapy, contributing to cancer recurrence. In this review, our objective is to explore novel avenues of research that delve into the distinctive characteristics of CSCs within their surrounding tumor microenvironment (TME). We will start with an overview of the defining features of CSCs and then delve into their intricate interactions with cells from the lymphoid lineage, namely T cells, B cells, and natural killer (NK) cells. Furthermore, we will discuss their dynamic interplay with myeloid lineage cells, including macrophages, neutrophils, and myeloid-derived suppressor cells (MDSCs). Moreover, we will illuminate the crosstalk between CSCs and cells of mesenchymal origin, specifically fibroblasts, adipocytes, and endothelial cells. Subsequently, we will underscore the pivotal role of CSCs within the context of the tumor-associated extracellular matrix (ECM). Finally, we will highlight pre-clinical and clinical studies that target CSCs within the intricate landscape of the TME, including CAR-T therapy, oncolytic viruses, and CSC-vaccines, with the ultimate goal of uncovering novel avenues for CSC-based cancer immunotherapy.

Functional Roles of CD133: More than Stemness Associated Factor Regulated by the Microenvironment

CD133 protein has been one of the most used surface markers to select and identify cancer cells with stem-like features. However, its expression is not restricted to tumoral cells; it is also expressed in differentiated cells and stem/progenitor cells in various normal tissues. CD133 participates in several cellular processes, in part orchestrating signal transduction of essential pathways that frequently are dysregulated in cancer, such as PI3K/Akt signaling and the Wnt/β-catenin pathway. CD133 expression correlates with enhanced cell self-renewal, migration, invasion, and survival under stress conditions in cancer. Aside from the intrinsic cell mechanisms that regulate CD133 expression in each cellular type, extrinsic factors from the surrounding niche can also impact CD33 levels. The enhanced CD133 expression in cells can confer adaptive advantages by amplifying the activation of a specific signaling pathway in a context-dependent manner. In this review, we do not only describe the CD133 physiological functions known so far, but importantly, we analyze how the microenvironment changes impact the regulation of CD133 functions emphasizing its value as a marker of cell adaptability beyond a cancer-stem cell marker.

Tyrosine glucosylation of collagen films exploiting Horseradish Peroxidase (HRP)

The development of human tissue models for regenerative medicine and animal-free drug screening requires glycosylated biomaterials such as collagen. An easy and fast biomaterial glycosylation method exploiting Horseradish Peroxidase (HRP) phenol coupling reaction is proposed. The protocol is adaptable to any polymer functionalized with phenol residues or tyrosine containing proteins. As a model the tyrosine residues on collagen films were functionalized with salidroside, a natural β-glucoside with a phenol in the aglycone. Scanning Electron Microscope (SEM) and contact angle analysis revealed the influence of glycosylation on the sample's morphology and wettability. Preliminary biological evaluation showed the cytocompatibility of the glucosylated collagen films.

Emerging role of interactions between tumor angiogenesis and cancer stem cells

Tumor angiogenesis and cancer stem cells (CSCs) are two major hallmarks of solid tumors. They have long received attention for their critical roles in tumor progression, metastasis and recurrence. Meanwhile, plenty of evidence indicates the close association between CSCs and tumor vasculature. CSCs are proven to promote tumor angiogenesis, and the highly vascularized tumor microenvironment further maintains CSCs growth in return, thereby forming a hard-breaking vicious circle to promote tumor development. Hence, though monotherapy targeting tumor vasculature or CSCs has been extensively studied over the past decades, the poor prognosis has been limiting the clinical application. This review summarizes the crosstalk between tumor vasculature and CSCs with emphasis on small-molecule compounds and the associated biological signaling pathways. We also highlight the importance of linking tumor vessels to CSCs to disrupt the CSCs-angiogenesis vicious circle. More precise treatment regimens targeting tumor vasculature and CSCs are expected to benefit future tumor treatment development.

Tissue-specific cancer stem/progenitor cells: Therapeutic implications

Surgical resection, chemotherapy, and radiation are the standard therapeutic modalities for treating cancer. These approaches are intended to target the more mature and rapidly dividing cancer cells. However, they spare the relatively quiescent and intrinsically resistant cancer stem cells (CSCs) subpopulation residing within the tumor tissue. Thus, a temporary eradication is achieved and the tumor bulk tends to revert supported by CSCs' resistant features. Based on their unique expression profile, the identification, isolation, and selective targeting of CSCs hold great promise for challenging treatment failure and reducing the risk of cancer recurrence. Yet, targeting CSCs is limited mainly by the irrelevance of the utilized cancer models. A new era of targeted and personalized anti-cancer therapies has been developed with cancer patient-derived organoids (PDOs) as a tool for establishing pre-clinical tumor models. Herein, we discuss the updated and presently available tissue-specific CSC markers in five highly occurring solid tumors. Additionally, we highlight the advantage and relevance of the three-dimensional PDOs culture model as a platform for modeling cancer, evaluating the efficacy of CSC-based therapeutics, and predicting drug response in cancer patients.

Claudin-4: A New Molecular Target for Epithelial Cancer Therapy

Claudin-4 (CLDN4) is a key component of tight junctions (TJs) in epithelial cells. CLDN4 is overexpressed in many epithelial malignancies and correlates with cancer progression. Changes in CLDN4 expression have been associated with epigenetic factors (such as hypomethylation of promoter DNA), inflammation associated with infection and cytokines, and growth factor signaling. CLDN4 helps to maintain the tumor microenvironment by forming TJs and acts as a barrier to the entry of anticancer drugs into tumors. Decreased expression of CLDN4 is a potential marker of epithelial-mesenchymal transition (EMT), and decreased epithelial differentiation due to reduced CLDN4 activity is involved in EMT induction. Non-TJ CLDN4 also activates integrin beta 1 and YAP to promote proliferation, EMT, and stemness. These roles in cancer have led to investigations of molecular therapies targeting CLDN4 using anti-CLDN4 extracellular domain antibodies, gene knockdown, clostridium perfringens enterotoxin (CPE), and C-terminus domain of CPE (C-CPE), which have demonstrated the experimental efficacy of this approach. CLDN4 is strongly involved in promoting malignant phenotypes in many epithelial cancers and is regarded as a promising molecular therapeutic target.

Increased Expression of the Pathological O-glycosylated Form of Oncofetal Fibronectin in the Multidrug Resistance Phenotype of Cancer Cells

Changes in protein glycosylation are a hallmark of transformed cells and modulate numerous phenomena associated with cancer progression, such as the acquisition of multidrug resistance (MDR) phenotype. Different families of glycosyltransferases and their products have already been described as possible modulators of the MDR phenotype. Among the glycosyltransferases intensively studied in cancer research, UDP-N-acetyl-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase-6 (pp-GalNAc-T6), which is widely expressed in many organs and tissues, stands out. Its influence in several events associated with kidney, oral, pancreatic, renal, lung, gastric and breast cancer progression has already been described. However, its participation in the MDR phenotype has never been studied. Here, we demonstrate that human breast adenocarcinoma MCF-7 MDR cell lines, generated by chronic exposure to doxorubicin, in addition to exhibiting increased expression of proteins belonging to the ABC superfamily (ABCC1 and ABCG2), and anti-apoptotic proteins (Blcl-2 and Bcl-xL), also present high expression of pp-GalNAc-T6, the enzyme currently proposed as the main responsible for the biosynthesis of oncofetal fibronectin (onf-FN), a major extracellular matrix component expressed by cancer cells and embryonic tissues, but absent in healthy cells. Our results show that onf-FN, which is generated by the addition of a GalNAc unit at a specific threonine residue inside the type III homology connective segment (IIICS) domain of FN, is strongly upregulated during the acquisition of the MDR phenotype. Also, the silencing of pp-GalNAc-T6, not only compromises the expression of the oncofetal glycoprotein, but also made the MDR cells more sensitive to all anticancer drugs tested, partially reversing the MDR phenotype. Taken together, our results demonstrate for the first time the upregulation of the O-glycosylated oncofetal fibronectin, as well as the direct participation of pp-GalNAc-T6 during the acquisition of a MDR phenotype in a breast cancer model, giving credence to the hypothesis that in transformed cells, glycosyltransferases and/or their products, such as unusual extracellular matrix glycoproteins can be used as potential therapeutic targets for the treatment of cancer.

Potential implications of the glycosylation patterns in collagen α1(I) and α2(I) chains for fibril assembly and growth

O-Glycosylation of hydroxylysine (Hyl) in collagen occurs at an early stage of biosynthesis before the triple-helix has formed. This simple post-translational modification (PTM) of lysine by either a galactosyl or glucosylgalactosyl moiety is highly conserved in collagens and depends on the species, type of tissue and the collagen amino acid sequence. The structural/functional reason why only specific lysines are modified is poorly understood, and has led to increased efforts to map the sites of PTMs on collagen sequences from different species and to ascertain their potential role in vivo. To investigate this, we purified collagen type I (Col1) from the skins of four animals, then used mass spectrometry and proteomic techniques to identify lysines that were oxidised, galactosylated, glucosylgalactosylated, or glycated in its mature sequence. We found 18 out of the 38 lysines in collagen type Iα1, (Col1A1) and 7 of the 30 lysines in collagen type Iα2 (Col1A2) were glycosylated. Six of these modifications had not been reported before, and included a lysine involved in crosslinking collagen molecules. A Fourier transform analysis of the positions of the glycosylated hydroxylysines showed they display a regular axial distribution with the same d-period observed in collagen fibrils. The significance of this finding in terms of the assembly of collagen molecules into fibrils and of potential restrictions on the growth of the collagen fibrils is discussed.

3D bioprinted colorectal cancer models based on hyaluronic acid and signalling glycans

In cancer microenvironment, aberrant glycosylation events of ECM proteins and cell surface receptors occur. We developed a protocol to generate 3D bioprinted models of colorectal cancer (CRC) crosslinking hyaluronic acid and gelatin functionalized with three signalling glycans characterized in CRC, 3'-Sialylgalactose, 6'-Sialylgalactose and 2'-Fucosylgalactose. The crosslinking, performed exploiting azide functionalized gelatin and hyaluronic acid and 4arm-PEG-dibenzocyclooctyne, resulted in biocompatible hydrogels that were 3D bioprinted with commercial CRC cells HT-29 and patient derived CRC tumoroids. The glycosylated hydrogels showed good 3D printability, biocompatibility and stability over the time. SEM and synchrotron radiation SAXS/WAXS analysis revealed the influence of glycosylation in the construct morphology, whereas MALDI-MS imaging showed that protein profiles of tumoroid cells vary with glycosylation, indicating that sialylation and fucosylation of ECM proteins induce diverse alterations to the proteome of the tumoroid and surrounding cells.

3D printed tissue models: From hydrogels to biomedical applications

The development of new advanced constructs resembling structural and functional properties of human organs and tissues requires a deep knowledge of the morphological and biochemical properties of the extracellular matrices (ECM), and the capacity to reproduce them. Manufacturing technologies like 3D printing and bioprinting represent valuable tools for this purpose. This review will describe how morphological and biochemical properties of ECM change in different tissues, organs, healthy and pathological states, and how ECM mimics with the required properties can be generated by 3D printing and bioprinting. The review describes and classifies the polymeric materials of natural and synthetic origin exploited to generate the hydrogels acting as "inks" in the 3D printing process, with particular emphasis on their functionalization allowing crosslinking and conjugation with signaling molecules to develop bio-responsive and bio-instructive ECM mimics.

The metastatic niche formation: focus on extracellular vesicle-mediated dialogue between lung cancer cells and the microenvironment

Lung cancer is the deadliest cancer in the world, with the majority of patients presenting with advanced or metastatic disease at first diagnosis. The lungs are also one of the most common sites of metastasis from lung cancer and other tumors. Understanding the mechanisms that regulate metastasis formation from primary lung cancer and in the lungs is therefore fundamental unmet clinical need. One of the first steps during the establishment of lung cancer metastases includes the formation of the pre-metastatic niche (PMN) at distant organs, which may occur even during the early phases of cancer development. The PMN is established through intricate cross-talk between primary tumor-secreted factors and stromal components at distant sites. Mechanisms controlling primary tumor escape and seeding of distant organs rely on specific properties of tumor cells but are also tightly regulated by interactions with stromal cells at the metastatic niche that finally dictate the success of metastasis establishment. Here, we summarize the mechanisms underlying pre-metastatic niche formation starting from how lung primary tumor cells modulate distant sites through the release of several factors, focusing on Extracellular Vesicles (EVs). In this context, we highlight the role of lung cancer-derived EVs in the modulation of tumor immune escape. Then, we illustrate the complexity of Circulating Tumor Cells (CTCs) that represent the seeds of metastasis and how interactions with stromal and immune cells can help their metastatic dissemination. Finally, we evaluate the contribution of EVs in dictating metastasis development at the PMN through stimulation of proliferation and control of disseminated tumor cell dormancy. Overall, we present an overview of different steps in the lung cancer metastatic cascade, focusing on the EV-mediated interactions between tumor cells and stromal/immune cells.

Chemotherapy as a regulator of extracellular matrix-cell communication: Implications in therapy resistance

The development of most solid cancers, including pancreatic, breast, lung, liver, and ovarian cancer, involves a desmoplastic reaction: a process of major remodeling of the extracellular matrix (ECM) affecting the ECM composition, mechanics, and microarchitecture. These properties of the ECM influence key cancer cell functions, including treatment resistance. Furthermore, emerging data show that various chemotherapeutic treatments lead to alterations in ECM features and ECM-cell communication. Here, we summarize the current knowledge around the effects of chemotherapy on both the ECM remodeling and ECM-cell signaling and discuss the implications of these alterations on distinct mechanisms of chemoresistance. Additionally, we provide an overview of current therapeutic strategies and ongoing clinical trials utilizing anti-cancer drugs to target the ECM-cell communication and explore the future challenges of these strategies.

The lipid rafts in cancer stem cell: a target to eradicate cancer

Cancer stem cells (CSCs) are a subpopulation of cancer cells with stem cell properties that sustain cancers, which may be responsible for cancer metastasis or recurrence. Lipid rafts are cholesterol- and sphingolipid-enriched microdomains in the plasma membrane that mediate various intracellular signaling. The occurrence and progression of cancer are closely related to lipid rafts. Emerging evidence indicates that lipid raft levels are significantly enriched in CSCs compared to cancer cells and that most CSC markers such as CD24, CD44, and CD133 are located in lipid rafts. Furthermore, lipid rafts play an essential role in CSCs, specifically in CSC self-renewal, epithelial-mesenchymal transition, drug resistance, and CSC niche. Therefore, lipid rafts are critical regulatory platforms for CSCs and promising therapeutic targets for cancer therapy.

Hypomethylation of CLDN4 Gene Promoter Is Associated with Malignant Phenotype in Urinary Bladder Cancer

The tight junction (TJ) protein claudin-4 (CLDN4) is overexpressed in bladder urothelial carcinoma (BUC) and correlates with cancer progression. However, the mechanism of CLDN4 upregulation and promotion of malignant phenotype is not clear. Here, we analyzed 157 cases of BUC and investigated the hypomethylation of CpG island in the CLDN4 promoter DNA and its correlation with cancer progression. In hypomethylated cases, CLDN4 expression, cell proliferation, stemness, and epithelial-mesenchymal transition were increased. Treatment of three human BUC cell lines with the demethylating agent aza-2′-deoxycytidine (AZA) led to excessive CLDN4 expression, and, specifically, to an increase in CLDN4 monomer that is not integrated into the TJ. The TJ-unintegrated CLDN4 was found to bind integrin β1 and increase stemness, drug resistance, and metastatic ability of the cells as well as show an anti-apoptosis effect likely via FAK phosphorylation, which reduces upon knockdown of CLDN4. Thus, CLDN4 is overexpressed in BUC by an epigenetic mechanism and the high expression enhances the malignant phenotype of BUC via increased levels of TJ-unintegrated CLDN4. CLDN4 promoter DNA methylation is expected to be a novel indicator of BUC malignant phenotype and a new therapeutic target.

Multiple roles for basement membrane proteins in cancer progression and EMT

Metastasis or the progression of malignancy poses a major challenge in cancer therapy and is the principal reason for increased mortality. The epithelial-Mesenchymal transition (EMT) of the Basement Membrane (BM) allows cells of epithelial phenotype to transform into a mesenchymal-like (quasi-mesenchymal) phenotype and metastasize via the lymphovascular system through a metastatic cascade by intravasation and extravasation. This helps in the progression of carcinoma from the primary site to distant organs. Collagen, laminin, and integrin are the prime components of BM and help in tumor cell metastasis, which makes them ideal cancer drug targets. Further, recent studies have shown that collagen, laminin, and integrin can be used as a biomarker for metastatic cells. In this review, we have summarized the current knowledge of such therapeutics, which are either currently in preclinical or clinical stages and could be promising cancer therapeutics. DATA AVAILABILITY: Not applicable.

New mechanistic insights to PLOD1-mediated human vascular disease

Heritable thoracic aortic disease and familial thoracic aortic aneurysm/dissection are important causes of human morbidity/mortality, most without identifiable genetic cause. In a family with familial thoracic aortic aneurysm/dissection, we identified a missense p. (Ser178Arg) variant in PLOD1 segregating with disease, and evaluated PLOD1 enzymatic activity, collagen characteristics and in human aortic vascular smooth muscle cells, studied the effect on function. Comparison with homologous PLOD3 enzyme indicated that the pathogenic variant may affect the N-terminal glycosyltransferase domain, suggesting unprecedented PLOD1 activity. In vitro assays demonstrated that wild-type PLOD1 is capable of processing UDP-glycan donor substrates, and that the variant affects the folding stability of the glycosyltransferase domain and associated enzymatic functions. The PLOD1 substrate lysine was elevated in the proband, however the enzymatic product hydroxylysine and total collagen content was not different, albeit despite collagen fibril narrowing and preservation of collagen turnover. In VSMCs overexpressing wild-type PLOD1, there was upregulation in procollagen gene expression (secretory function) which was attenuated in the variant, consistent with loss-of-function. In comparison, si-PLOD1 cells demonstrated hypercontractility and upregulation of contractile markers, providing evidence for phenotypic switching. Together, the findings suggest that the PLOD1 product is preserved, however newly identified glucosyltransferase activity of PLOD1 appears to be affected by folding stability of the variant, and is associated with compensatory vascular smooth muscle cells phenotypic switching to support collagen production, albeit with less robust fibril girth. Future studies should focus on the impact of PLOD1 folding/variant stability on the tertiary structure of collagen and ECM interactions.

Genetic and Epigenetic Aspects of Skin Collagen Fiber Turnover and Functioning

One of the most important functions of the skin, i.e., protection from mechanical damage, is ensured by collagen fibers and their interaction with other elements in the extracellular matrix. Collagen fiber turnover is a complex multi-stage process. At each stage, a disruption may occur, leading to a decrease in the mechanical properties of the connective tissue. Clinically, collagen formation disorders manifest themselves as increased flabbiness and looseness of the skin and as early signs of facial aging. In addition to the clinical picture, it is important for cosmetologists and dermatologists to understand the etiology and pathogenesis of collagenopathies. In our review, we summarized and systematized the available information concerning the role of genetic and epigenetic factors in skin collagen fiber turnover. Furthermore, we focused on the functions of different types of collagens present in the skin. Understanding the etiology of impaired collagen formation can allow doctors to prescribe pathogenetically based treatments, achieve the most effective results, and minimize adverse reactions.

Abnormal Glycosylation of Cancer Stem Cells and Targeting Strategies

Cancer stem cell (CSCs) are deemed as one of the main reasons of tumor relapse due to their resistance to standard therapies. Numerous intracellular signaling pathways along with extracellular features are crucial in regulating CSCs properties, such as heterogeneity, plasticity and differentiation. Aberrant glycosylation of these cellular signaling pathways and markers of CSCs have been directly correlated with maintaining survival, self-renewal and extravasation properties. In this review, we highlight the importance of glycosylation in promoting stemness character of CSCs, and present strategies for targeting abnormal glycosylation to eliminate the resistant CSC population.

Cellular Immunotherapy Targeting Cancer Stem Cells: Preclinical Evidence and Clinical Perspective

The term “cancer stem cells” (CSCs) commonly refers to a subset of tumor cells endowed with stemness features, potentially involved in chemo-resistance and disease relapses. CSCs may present peculiar immunogenic features influencing their homeostasis within the tumor microenvironment. The susceptibility of CSCs to recognition and targeting by the immune system is a relevant issue and matter of investigation, especially considering the multiple emerging immunotherapy strategies. Adoptive cellular immunotherapies, especially those strategies encompassing the genetic redirection with chimeric antigen receptors (CAR), hold relevant promise in several tumor settings and might in theory provide opportunities for selective elimination of CSC subsets. Initial dedicated preclinical studies are supporting the potential targeting of CSCs by cellular immunotherapies, indirect evidence from clinical studies may be derived and new studies are ongoing. Here we review the main issues related to the putative immunogenicity of CSCs, focusing on and highlighting the existing evidence and opportunities for cellular immunotherapy approaches with T and non-T antitumor lymphocytes.