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The RNase activity of MCPIP1 is essential for regulating cellular homeostasis, proliferation, and tumorigenesis. Our study elucidates the effects of downregulation of MCPIP1 expression and an RNase-inactivating mutation (D141N) on normal epithelial kidney cells, indicating that MCPIP1 expression is a key factor that suppresses neoplastic transformation. We observed that either expression downregulation or mutation of MCPIP1 significantly increased its clonogenicity and altered the expression of cancer stem cell (CSC) markers and factors involved in epithelial-to-mesenchymal transition (EMT). In vivo studies demonstrated that MCPIP1 inactivation in normal epithelial cells leads to significant tumor formation and increased c-Myc phosphorylation, indicating enhanced cell proliferation. Proteomic analysis of mouse plasma revealed increased secretion of cancer-related proteins (CXCL13, CXCL16, and MMP2) in the MCPIP1-mutant group. Additionally, we revealed that MCPIP1 RNase activity regulates the expression of the stemness markers CD44 and CD133 and the phosphorylation of the c-Met receptor in tumor tissue samples. Mechanistically, via coimmunoprecipitation analysis, we found that the RNase activity of MCPIP1 controls CD44 expression and, consequently, that a strong interaction between CD44 and c-Met leads to c-Met activation. This regulation was confirmed in patient samples, in which increased CD44 expression correlated with ccRCC progression. These findings highlight the critical role of MCPIP1 RNase activity in modulating the c-Met/CD44 axis, thereby influencing stemness and tumorigenesis. [ABSTRACT FROM AUTHOR]

Parietal Epithelial Cells (PECs) activation and proliferation are common to several distinct forms of glomerulopathies. Due to several stimuli, PECs can change to a progenitor (CD24+ and CD133/2+) or a pro-sclerotic (CD44+) phenotype. In addition, PECs, which are constantly exposed to filtered albumin, are known to be involved in albumin internalization, but how this mechanism occurs is unknown. We hypothesized that PECs can transport albumin via receptor-mediated endocytosis and that albumin overload may affect the state of PECs. Conditionally immortalized human PECs (hPECs) were incubated with different albumin concentrations at different times. Albumin internalization studies were performed. Protein expression was assessed using In-Cell Western and immunofluorescence. Cell morphology was analyzed by phase-contrast microscopy and F-actin staining. We demonstrate that hPECs internalize albumin via receptor-mediated mechanisms. Under albumin stimulation, megalin, cubilin, ClC-5, CD133/2, CD24, and CD44 were upregulated. The increase of pERK1/2, the upregulation of ROCK1, ROCK2, caspase -3, -6, and -7, and the morphological changes associated with loss of F-actin fibers indicated that inflammation, proliferation and apoptosis mechanisms had been activated. Our results demonstrate that long-term exposure to high doses of albumin induces up-regulation of molecules involved in the tubular protein uptake machinery and suggest that albumin overload is able to trigger a regenerative process as well as an activation state which might lead in vivo to glomerular crescent formation. [ABSTRACT FROM AUTHOR]

Aim: Epithelial splicing regulatory protein 1 (ESRP1) regulates tumor progression and metastasis through the epithelial‒mesenchymal transition by interacting with zinc finger E‐box binding 1 (ZEB1) and CD44 in cancers. However, the role of ESRP1 in intrahepatic cholangiocarcinoma (iCCA) remains unclear. Methods: Three iCCA cell lines (HuCCT‐1, SSP‐25, and KKU‐100) were analyzed using small interfering RNA to investigate the molecular biological functions of ESRP1 and ZEB1. The association between clinicopathological features and the expression of ESRP1 and ZEB1 in iCCA tissues was analyzed immunohistochemically. Proteomic analysis was performed to identify molecules related to ESRP1 expression. Results: ESRP1 expression was upregulated in HuCCT‐1 and SSP‐25 cells. Cell migration and invasion were enhanced, and the expression of ZEB1 and CD44s (CD44 standard) isoforms were upregulated in the ESRP1 silencing cells. Moreover, ESRP1 silencing increased the expression of N‐cadherin and vimentin, indicating the presence of mesenchymal properties. Conversely, ZEB1 silencing increased the expression of ESRP1 and CD44v (CD44 variant) isoforms. Immunohistochemical analysis revealed that a lower ESRP1‐to‐ZEB1 expression ratio was associated with poor recurrence‐free survival in patients with iCCA. Flotillin 2, a lipid raft marker related to epithelial‒mesenchymal transition, was identified as a protein related to the interactive feedback loop in proteomic analysis. Conclusions: ESRP1 suppresses tumor progression in iCCA by interacting with ZEB1 and CD44 to regulate epithelial‒mesenchymal transition. [ABSTRACT FROM AUTHOR]

Background: Cluster of differentiation 44 (CD44) is the most commonly reported immune marker of the cancer stem cells in renal cell carcinoma. Objectives: To assess the frequency of CD44 expression in renal tumors, to assess the expression of CD44 in different histological types, and to detect its association with variable clinicopathological parameters. Materials and methods: In this retrospective case series study, 76 cases of primary renal tumors were obtained by nephrectomy, and a study of CD44 was done by using the immunohistochemical technique. Results: The age of the patients ranged from 29–82 years with a mean of 54.8 ± 11.96 with a male to female ratio of 1.05:1. Tumor size ranged from 2–17 cm with a mean of 6.2 ± 3.23. Clear cell renal cell carcinoma was forming 61.83% of the cases. Among all cases, a positive CD44 expression was observed in 35 (46.05%) cases; among the malignant cases, CD44 was positive in 32 (45.71%). CD44 immunohistochemical stain showed significantly higher expression in cases with higher nuclear grade and tumor stage (P-value of 0.0376 and 0.0075, respectively). CD44 cannot differentiate between benign and malignant renal tumors. Conclusion: CD44 immune marker can be used as a prognostic factor to predict the aggressive behavior of renal tumors. It can also be used with standard prognostic markers to add prognostic information for subgrouping cases within the same grade and stage. [ABSTRACT FROM AUTHOR]

Purpose: The epithelial–mesenchymal transition of human lens epithelial cells plays a role in posterior capsule opacification, a fibrotic process that leads to a common type of cataract. Hyaluronic acid has been implicated in this fibrosis. Studies have investigated the role of transforming growth factor (TGF)-β2 in epithelial–mesenchymal transition. However, the role of TGF-β2 in hyaluronic acid-mediated fibrosis of lens epithelial cell remains unknown. We here examined the role of TGF-β2 in the hyaluronic acid-mediated epithelial–mesenchymal transition of lens epithelial cells. Methods: Cultured human lens epithelial cells (HLEB3) were infected with CD44-siRNA by using the Lipofectamine 3000 transfection reagent. The CCK-8 kit was used to measure cell viability, and the scratch assay was used to determine cell migration. Cell oxidative stress was analyzed in a dichloro-dihydro-fluorescein diacetate assay and by using a flow cytometer. The TGF-β2 level in HLEB3 cells was examined through immunohistochemical staining. The TGF-β2 protein level was determined through western blotting. mRNA expression levels were determined through quantitative real-time polymerase chain reaction. Results: Treatment with hyaluronic acid (1.0 μM, 24 h) increased the epithelial–mesenchymal transition of HLEB3 cells. The increase in TGF-β2 levels corresponded to an increase in CD44 levels in the culture medium. However, blocking the CD44 function significantly reduced the TGFβ2-mediated epithelial–mesenchymal transition response of HLEB3 cells. Conclusions: Our study showed that both CD44 and TGF-β2 are critical contributors to the hyaluronic acid-mediated epithelial-mesenchymal transition of lens epithelial cells, and that TGF-β2 in epithelial-mesenchymal transition is regulated by CD44. These results suggest that CD44 could be used as a target for preventing hyaluronic acid-induced posterior capsule opacification. Our findings suggest that CD44/TGF-β2 is crucial for the hyaluronic acid-induced epithelial-mesenchymal transition of lens epithelial cells. [ABSTRACT FROM AUTHOR]

Objective: Meningiomas are a molecularly ill-defined heterogeneous group of indolent intracranial tumors. Though, WHO grade 1 tumors are histologically benign, sometimes they transform into malignant and may be recurrent which remains always challenging to clinicians. Therefore, the current study sought to discover the clinical relevance of CD44 in meningioma patients. Method: Protein expression of CD44 was investigated using immunohistochemistry in a total of 70 meningioma patients. Immunoscore performed using modified H-score, CD44 expression correlated with clinicopathological parameters and progression-free survival (PFS) and overall survival (OS). Univariate and multivariate survival analysis was analyzed. The data was evaluated using SPSS statistical software and P-value ≤ 0.05 was considered as significant. Results: The membranous and cytoplasmic protein expression of CD44 was noted in meningioma tumors. Based on H-score, the weak (0–190 score) and strong (191–300 score) immunoreactivity was observed in 62.9% and 37.1% of patients, respectively. A statistically significant positive correlation was found between strong CD44 expression and WHO grade 2/3 tumors (χ2 = 33.551, r = + 0.692, P = 0.0001), and with the presence of brain invasion (χ2 = 19.521, r = + 0.528, P = 0.001). In Kaplan–Meier univariate survival analysis for PFS and OS, apart from WHO grade of tumors (PFS; log-rank = 12.309, P = 0.0001, OS; log-rank = 17.830, P = 0.0001) and brain invasion status (PFS; log-rank = 11.941, P = 0.001, OS; log-rank = 13.554, P = 0.0001) CD44 expression (PFS; log-rank = 14.942, P = 0.0001, OS; log-rank = 20.986, P = 0.0001) remained significant prognostic factor for PFS and OS. In multivariate survival analysis, at step 1, only CD44 remained independent prognosticator for PFS (HR = 11.014, 95% CI = 2.256–23.602, P = 0.001) and OS (HR = 8.553, 95% CI = 2.831–25.847, P = 0.0001). In relation to treatment offered, patients with strong CD44 expression and if treated with surgery followed by adjuvant radiotherapy showed a high incidence of death (log-rank = 13.402, P = 0.0001) as compared to patients treated with surgery only. Receiver operating characteristic (ROC) curves also confirmed a good efficacy of CD44 as a prognosticator for disease outcome (PFS; P = 0.0001, OS; P = 0001). Conclusion: Our overall findings addressed that a study of CD44 protein expression would be beneficiated to meningioma patients from unnecessary overtreatment and drug-induced toxicity. Also, CD44 could be one of the promising biomarkers that might differentiate high-risk meningioma patients for better treatment management. [ABSTRACT FROM AUTHOR]

Background: Glioblastoma (GBM) is an aggressive brain tumor driven by glioblastoma stem cells (GSCs), which represent an appealing target for therapeutic interventions. The cellular prion protein (PrPC), a scaffold protein involved in diverse cellular processes, interacts with various membrane and extracellular matrix molecules, influencing tumor biology. Herein, we investigate the impact of PrPC expression on GBM. Methods: To address this goal, we employed CRISPR-Cas9 technology to generate PrPC knockout (KO) glioblastoma cell lines, enabling detailed loss-of-function studies. Bulk RNA sequencing followed by differentially expressed gene and pathway enrichment analyses between U87 or U251 PrPC-wild-type (WT) cells and PrPC-knockout (KO) cells were used to identify pathways regulated by PrPC. Immunofluorescence assays were used to evaluate cellular morphology and protein distribution. For assessment of protein levels, Western blot and flow cytometry assays were employed. Transwell and growth curve assays were used to determine the impact of loss-of-PrPC in GBM invasiveness and proliferation, respectively. Single-cell RNA sequencing analysis of data from patient tumors from The Cancer Genome Atlas (TCGA) and the Broad Institute of Single-Cell Data Portal were used to evaluate the correspondence between our in vitro results and patient samples. Results: Transcriptome analysis of PrPC-KO GBM cell lines revealed altered expression of genes associated with crucial tumor progression pathways, including migration, proliferation, and stemness. These findings were corroborated by assays that revealed impaired invasion, migration, proliferation, and self-renewal in PrPC-KO GBM cells, highlighting its critical role in sustaining tumor growth. Notably, loss-of-PrPC disrupted the expression and localization of key stemness markers, particularly CD44. Additionally, the modulation of PrPC levels through CD44 overexpression further emphasizes their regulatory role in these processes. Conclusions: These findings establish PrPC as a modulator of essential molecules on the cell surface of GSCs, highlighting its potential as a therapeutic target for GBM. [ABSTRACT FROM AUTHOR]

Accumulating evidences have indicated that cancer stem cells (CSCs) can initiate tumor progression and cause recurrence after therapy. However, specific markers of gastric CSCs (GCSCs) from different origins have not been comprehensively revealed. Here, we further detected whether cell populations labelled with CD44 and Lgr5, well-recognized stem markers for gastric cancer (GC), can better emphasize cancer initiation, therapeutic resistance and recurrence. Flow cytometry was utilized to sort the CD44 + Lgr5 + and CD44 + Lgr5- cells from GC cell line HGC-27 and primary GC cells. The influences of CD44 and Lgr5 GCSCs on the malignant behaviors and their potential mechanisms was investigated, respectively. In our study, we reported the identification and validation of CD44 + Lgr5 + cells that presented stronger stemness characteristics, as evidenced by increase of sphere forming ability, elevation of stem cell transcriptional activity. Additionally, CD44 + Lgr5 + double positive cells have lower apoptosis, greater chemotherapy resistance, and higher EMT capacity and LC3 density compared with CD44 + Lgr5- cells. Tumor xenograft experiments also verified the faster carcinogenesis of CD44 + Lgr5 + GCSCs. Furthermore, a series of key proteins in the Wnt, Hedgehog, Notch, and TGF-β pathways were elevated in the CD44 + Lgr5 + double positive subpopulation, except for Notch 1 and Smad 1. In conclusion, the binding of CD44 and Lgr5 can serve as a precise GCSCs marker that initiate malignant progression and chemotherapy resistance in GC by activating Wnt, Hedgehog, Notch, TGF-β pathways. Those evidences raise the needs to target both markers simultaneously as a potential approach for the GC treatment. 1. CD44+Lgr5+ GCSCs exhibited the activation of Hedgehog pathway, and Wnt/β-catenin pathway. 2. In terms of the Notch pathway, all Notch proteins and NICD were elevated in CD44+Lgr5+ GCSCs except Notch 1 protein. 3. TGF/β components including TGF-β1 and Smad 2, 3, and 4 were involved in stemness phenotypes of CD44+Lgr5+ GCSCs. [ABSTRACT FROM AUTHOR]

Glioblastoma stem cells (GSCs) are key drivers of relapse, metastasis, and therapy resistance in glioblastoma due to their adaptability and diversity, which make them challenging to target effectively. This study explores the O-glycosylation in differentiating two key GSC subtypes, CD133 and CD44. We utilized the TCGA dataset of GBM and presented the reproducible bioinformatics analysis for our results. Our profiling showed enriched O-glycosylation signatures in CD44-expressing GBM cells over CD133, with Cosmc, the chaperone for core mucin-type O-glycosylation, significantly upregulated in the CD44-positive group. Moreover, Cosmc was associated with shorter progression-free intervals, suggesting its potential as an indicator of aggressive disease. High Cosmc expression also enriched immune-related pathways, including inflammatory response and antigen presentation, and was associated with presence of myeloid cells, T cells, and NK cells. Additionally, elevated Cosmc correlated with extracellular matrix (ECM) pathways and stromal cell populations, such as perivascular fibroblasts. These findings position O-glycosylation, specially, Cosmc as a promising biomarker for distinguishing GSC subclones, with relevance to immune modulation, and ECM dynamics, identifying it as a potential target for novel GBM therapies. [ABSTRACT FROM AUTHOR]

Chronic lymphocytic leukaemia (CLL) is a heterogenous disease characterized by the accumulation of neoplastic CD5+/CD19+ B lymphocytes. The spreading of the leukaemia relies on the CLL cell's ability to survive in the blood and migrate to and proliferate within the bone marrow and lymphoid tissues. Some patients with CLL are either refractory to the currently available therapies or relapse after treatment; this emphasizes the need for novel therapeutic strategies that improving clinical responses and overcome drug resistance. CD38 is a marker of a poor prognosis and governs a set of survival, proliferation and migration signals that contribute to the pathophysiology of CLL. The literature data evidence a spatiotemporal association between the cell surface expression of CD38 and that of other CLL antigens, such as the B-cell receptor (BCR), CD19, CD26, CD44, the integrin very late antigen 4 (VLA4), the chemokine receptor CXCR4, the vascular endothelial growth factor receptor-2 (VEGF-R2), and the neutrophil gelatinase-associated lipocalin receptor (NGAL-R). Most of these proteins contribute to CLL cell survival, proliferation and trafficking, and cooperate with CD38 in multilayered signal transduction processes. In general, these antigens have already been validated as therapeutic targets in cancer, and a broad repertoire of specific monoclonal antibodies and derivatives are available. Here, we review the state of the art in this field and examine the therapeutic opportunities for cotargeting CD38 and its partners in CLL, e.g. by designing novel bi-/trispecific antibodies. [ABSTRACT FROM AUTHOR]

• Circulatory HAPLN1 level decreased with aging. • Restoking HAPLN1 in aged mice elevates skin collagen and hyaluronic acid levels. • rhHAPLN1 prevents TGF-β R2 degradation in dermal fibroblast thus up-regulates collagen and HA production. • rhHAPLN1 down-regulates endocytosis frequency and promotes CD44 clustering. • rhHAPLN1 rejuvenates skin aging by up-regulating HA-CD44-mediated TGF-β and NRF2 signaling. The skin seems to rejuvenate upon exposure to factors within the circulation of young organisms. Intrinsic factors that modulate skin aging are poorly understood. We used heterochronic parabiosis and aptamer-based proteomics to identify serum-derived rejuvenating factors. We discovered a novel extracellular function of hyaluronan and proteoglycan link protein 1 (HAPLN1). Its serum levels decreased with age, disturbing the integrity of the skin extracellular matrix, which is predominantly composed of collagen I and hyaluronan; levels of various markers, which decrease in aged skin, were significantly restored in vivo and in vitro by the administration of recombinant human HAPLN1 (rhHAPLN1). rhHAPLN1 protected transforming growth factor beta receptor 2 on the cell surface from endocytic degradation via mechanisms such as regulation of viscoelasticity, CD44 clustering. Moreover, rhHAPLN1 regulated the levels of nuclear factor erythroid 2–related factor 2, phosphorylated nuclear factor kappa B, and some cyclin-dependent kinase inhibitors such as p16 and p21. Therefore, rhHAPLN1 may act as a novel biomechanical signaling protein to rejuvenate aged skin. [ABSTRACT FROM AUTHOR]

Cancer stem cells (CSC) are a small number of tumour propagating cells present in the bulk of tumour cells. Expression of biological markers for CSCs viz. cluster of differentiation 24 and 44 (CD24, CD44) and aldehyde dehyodeganse 1 (ALDH1) imply aggressive tumour cell behaviour and poorer outcome, particularly in breast cancer. N = 75 Tumor tissue samples from enrolled breast cancer patients were obtained and subjected to histopathological examination and immunohistochemistry (IHC) after informed consent from patients. In addition to the estrogen receptor, progesterone receptor, Her2 neu receptor, and Ki67 index; IHC was also performed for CD24, CD44 and ALDH1A3 expression. These markers' positivity was correlated with clinical parameters, therapy response and metastasis prognostication. Most patients had higher tumor stage and high nodal burden (81.3% with node positivity; N1—68%, N2 -6.6%, N3—6.6%). Study showed significant association of CD24-/CD44 + group (p = 0.021) with distant metastasis and significant association of CD24-/CD44 + /ALDH1A3 + (p = 0.008) with higher stage (T4 stage). Tumor tissues expressing CD24-/CD44 + /ALDH1A3 + group (p = 0.010) and CD24 + /CD44 + / ALDH1A3 + (p = 0.010) were significantly associated with poor response to treatment. The correlation of CD24-/CD44 + was also statistically significant (p = 0.009). Positive expression of either CD24 and/or CD44 presented with aggressive disease, larger tumours and heavy nodal burden at a younger age. Additionally, ALDH1A3 positivity signified higher metastasis rates. CD24-/CD44 + /ALDH1A3 + and CD24 + /CD44 + / ALDH1A3 + correlated with greater chances of distant metastasis, aggressive disease, limited response to chemotherapy and poorer prognosis. Thus, these observations establish the role of these CSC phenotypes as important factors for prognostic outcomes and predictors of adverse outcomes. CD24-/CD44 + /ALDH1A3 + expression could serve as an important prognostic marker and predictor of adverse outcomes in Indian breast cancer tumour biology. [ABSTRACT FROM AUTHOR]

Objectives Methods Results Conclusion The study aimed to evaluate the expression of CD44, CD47, interleukin‐1 (IL‐1), and tumor necrosis factor alpha (TNF‐α) in immunohistochemically stained (IHS) samples from endometrioid endometrial cancer (EEC) and to examine their correlation with clinicopathologic parameters.IHS was used to assess CD44, CD47, IL‐1, and TNF‐α expression in 53 EEC samples. Immunostaining was scored as negative (−), slightly positive (+), moderately positive (++), or strongly/diffuse positive (+++). The prognostic value of these markers was analyzed in relation to clinicopathologic features, including survival.In endometrial cancer tissues, positivity rates were CD44 (81%), CD47 (81%), TNF‐α (40.5%), and IL‐1 (42.9%). Strong and diffuse CD44 staining was associated with improved survival and linked to endocervical invasion and stage. Patients with slightly positive CD47 had significantly higher rates of pelvic and para‐aortic lymph node metastases. Strong TNF‐α staining correlated with grade 3 EEC, while slightly positive IL‐1 staining was associated with increased endocervical invasion. No significant correlation was found between CD47, IL‐1, and TNF‐α expression and survival.CD44 and CD47 were positive in most EEC specimens. CD44 expression was the only marker significantly correlated with overall survival and recurrence. TNF‐α showed a positive correlation with high‐grade tumors, and IL‐1 staining was inversely associated with endocervical invasion. These findings suggest that CD44 is a prognostic marker for survival, while TNF‐α and IL‐1 may have indirect prognostic roles in EEC. [ABSTRACT FROM AUTHOR]

Medullary thyroid carcinoma (MTC) is a rare and aggressive tumor, often requiring systemic treatment in advanced or metastatic stages, where drug resistance presents a significant challenge. Given the role of cancer stem cells (CSCs) in cancer recurrence and drug resistance, we aimed to identify CSC subpopulations within two MTC cell lines harboring pathogenic variants in the two most common MEN2-associated codons. We analyzed 15 stemness-associated markers, along with well-established thyroid stem cell markers (CD133, CD44, and ALDH1), a novel candidate (DLK1), and multidrug resistance proteins (MRP1 and MRP3). The ability to efflux the fluorescent dye Hoechst 3342 and form spheroids, representing CSC behavior, was also assessed. MZ-CRC-1 cells (p.M918T) displayed higher expressions of canonical markers, DLK1, and MRP proteins than TT cells (p.C634W). MZ-CRC-1 cells also formed more spheroids and showed less dye accumulation (p < 0.0001). Finally, we observed that DLK1+ cells (those expressing DLK1) in both cell lines exhibited significantly higher levels of stemness markers compared to DLK1− cells (those lacking DLK1 expression). These findings underscore DLK1's role in enhancing the stemness phenotype, providing valuable insights into MTC progression and resistance and suggesting potential therapeutic implications. [ABSTRACT FROM AUTHOR]

Melanoma is a malignant, highly metastatic neoplasm showing increasing morbidity and mortality. Tumor invasion and angiogenesis are based on remodeling of the extracellular matrix (ECM). Selective inhibition of functional components of cell–ECM interaction, such as hyaluronic acid (HA), matrix metalloproteinases (MMPs), and integrins, may inhibit tumor progression and enhance the efficacy of combination treatment with immune checkpoint inhibitors (ICIs), chemotherapy, or immunotherapy. In this review, we combine the results of different approaches targeting extracellular matrix elements in melanoma in preclinical and clinical studies. The identified limitations of many approaches, including side effects, low selectivity, and toxicity, indicate the need for further studies to optimize therapy. Nevertheless, significant progress in expanding our understanding of tumor biology and the development of targeted therapies holds great promise for the early approaches developed several decades ago to inhibit metastasis through ECM targeting. [ABSTRACT FROM AUTHOR]

Objectives: To isolate cancer stem cells (CSC) from a metastatic oral squamous cell carcinoma (OSCC) cell line and investigate their in vitro and in vivo phenotypic characteristics. Materials and Methods: Subpopulations with individual staining intensities for CD44 and CD326 were isolated from the OSCC cell line LN‐1A by FACS: CD44Low/CD326− (CSC‐M1), CD44Low/CD326High (CSC‐E), and CD44High/CD326− (CSC‐M2). Proliferation, clonogenic potential, adhesion, migration, epithelial‐mesenchymal transition markers, and sensitivity to cisplatin and TVB‐3166 were analyzed in vitro. Tumor formation and metastasis were assessed by subcutaneous and orthotopic inoculations into BALB/c mice. Results: E‐cadherin levels were higher in CSC‐E cells while vimentin and Slug more produced by CSC‐M2 cells. CSC‐M1 and CSC‐M2 subpopulations showed higher proliferation, produced more colonies, and have stronger adhesion to the extracellular matrix. All cell lines established tumors; however, CSC‐E and CSC‐M2 formed larger masses and produced more metastases. Conclusion: The CSC subpopulations here described show increased cancer capabilities in vitro, tumorigenic and metastatic potential in vivo, and may be exploited in the search for novel therapeutic targets for OSCC. [ABSTRACT FROM AUTHOR]

Recently, the potential association between polycystic ovary syndrome (PCOS) development and progression and ferroptosis has garnered attention. Increasing evidence suggests that targeting ferroptosis may be an effective strategy for treating PCOS. First, we observed that the expression of the ferroptosis regulatory molecules SLC7A11, GPX4, and FTH1 was decreased in the granulosa cells (GCs) of patients with PCOS and ovarian tissues of rats with PCOS; in contrast, TFR1 expression was increased. This suggests that GC ferroptosis is involved in PCOS pathogenesis. Furthermore, bioinformatics analysis of GC datasets from patients with PCOS and PCOS clinical samples and animal model analysis revealed CD44 as a key molecule regulating ferroptosis in PCOS, which was down-regulated in GCs of PCOS patients and rats. Subsequently, molecular docking was performed to screen existing natural compounds for inhibiting ferroptosis. Dynamic simulation and cellular thermal shift assay identified platycodin D as a natural plant extract for inhibiting ferroptosis by targeting CD44 in GCs. Subsequently, a series of functional experiments revealed that platycodin D ameliorated ovarian damage in rats with PCOS. This was primarily owing to the protective effects achieved by promoting glutathione production, attenuating lipid accumulation and lipid peroxidation in GCs, inhibiting iron overload, and scavenging reactive oxygen species. In addition, western blotting and immunofluorescence staining revealed that platycodin D upregulated the expression of CD44 and SLC7A11 in GCs. Furthermore, by knocking down CD44 and SLC7A11 in vivo and in vitro , respectively, the ameliorative effect of platycodin D on ferroptosis in the GCs of rats with PCOS was reversed. Collectively, these findings suggest that platycodin D attenuates ferroptosis in GCs by activating CD44/SLC7A11 axis, thereby upregulating system X c −. In conclusion, platycodin D can attenuate ferroptosis in GCs by activating CD44, potentially ameliorating ovarian damage in PCOS. [Display omitted] • Ferroptosis in granulosa cells is elevated in patients with PCOS. • CD44 is a Key Regulator of Ferroptosis in PCOS. • Platycodin D attenuates PCOS phenotypes in rats. • Platycodin D alleviates ferroptosis in KGN cells and PCOS rats by activating CD44/SLC7A11. [ABSTRACT FROM AUTHOR]

Simple Summary: Understanding neural crest stem cells as the cells of origin for a series of tumors expands the potential strategies for treatment, especially for rare tumor types. The shared properties and signatures of stem-like tumor cells, also called cancer stem cells (CSCs), are reviewed for neural crest-originated tumors. Scrutinizing the relationship between neural crest stem cells and CSCs in NF1-associated tumors can allow for earlier detection and treatment in NF1 patients. Previously identified CSC markers can be the key to NF1 tumor pathogenesis and therapeutic targets. Targeting CD44, for example, can potentially reduce CSC-related tumor progression, relapse, and even metastasis. This review delineates the reported CSCs in tumors of neural crest origin and highlights their potential relevance in NF1-associated tumors. Neurofibromatosis type 1 (NF1) is a genetic disorder that predisposes individuals to develop benign and malignant tumors of the nerve sheath. Understanding the signatures of cancer stem cells (CSCs) for NF1-associated tumors may facilitate the early detection of tumor progression. Background: Neural crest cells, the cell of origin of NF1-associated tumors, can initiate multiple tumor types, including melanoma, neuroblastoma, and schwannoma. CSCs within these tumors have been reported; however, identifying and targeting CSC populations remains a challenge. Results: This study aims to leverage existing studies on neural crest-derived CSCs to explore markers pertinent to NF1 tumorigenesis. By focusing on the molecular and cellular dynamics within these tumors, we summarize CSC signatures in tumor maintenance, progression, and treatment resistance. Conclusion: A review of these signatures in the context of NF1 will provide insights into NF1 tumor biology and pave the way for developing targeted therapies and improving treatment outcomes for NF1 patients. [ABSTRACT FROM AUTHOR]

Plasma levels of oncofetal chondroitin sulfate (ofCS)‐modified CD44 have emerged as a promising biomarker for multi‐cancer detection. Here, we explored its potential to predict the survival of patients with lung cancer. A prospective observational cohort was conducted involving 274 newly diagnosed patients with lung cancer at the Sun Yat‐sen University Cancer Center from 2013 to 2015. The plasma levels of ofCS‐modified CD44 were measured, and Cox regression analysis was performed to assess the association between plasma‐modified CD44 levels and overall survival (OS) as well as other prognostic outcomes. Prognostic nomograms were constructed based on plasma ofCS‐modified CD44 levels to predict survival outcomes for patients with lung cancer. Patients with high expression ofCS‐modified CD44 exhibited significantly worse outcomes in terms of OS (HR = 1.61, 95%CI = 1.13–2.29, p = 0.009) and progression‐free survival (PFS). These findings were consistent across various analyses. The concordance index of the prognostic nomogram for predicting OS in both the training set and validation set were 0.723 and 0.737, respectively. Additionally, time‐dependent receiver operating characteristic (ROC) curves showed that the nomogram could serve as a useful tool for predicting OS in patients with lung cancer. Plasma ofCS‐modified CD44 may serve as an independent prognosis marker for patients with lung cancer. Further validation of its predictive value could enhance prognostic assessment and guide personalized treatment strategies for patients with lung cancer. [ABSTRACT FROM AUTHOR]

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Abstract Objective Meningiomas are a molecularly ill-defined heterogeneous group of indolent intracranial tumors. Though, WHO grade 1 tumors are histologically benign, sometimes they transform into malignant and may be recurrent which remains always challenging to clinicians. Therefore, the current study sought to discover the clinical relevance of CD44 in meningioma patients. Method Protein expression of CD44 was investigated using immunohistochemistry in a total of 70 meningioma patients. Immunoscore performed using modified H-score, CD44 expression correlated with clinicopathological parameters and progression-free survival (PFS) and overall survival (OS). Univariate and multivariate survival analysis was analyzed. The data was evaluated using SPSS statistical software and P-value ≤ 0.05 was considered as significant. Results The membranous and cytoplasmic protein expression of CD44 was noted in meningioma tumors. Based on H-score, the weak (0–190 score) and strong (191–300 score) immunoreactivity was observed in 62.9% and 37.1% of patients, respectively. A statistically significant positive correlation was found between strong CD44 expression and WHO grade 2/3 tumors (χ 2 = 33.551, r = + 0.692, P = 0.0001), and with the presence of brain invasion (χ 2 = 19.521, r = + 0.528, P = 0.001). In Kaplan–Meier univariate survival analysis for PFS and OS, apart from WHO grade of tumors (PFS; log-rank = 12.309, P = 0.0001, OS; log-rank = 17.830, P = 0.0001) and brain invasion status (PFS; log-rank = 11.941, P = 0.001, OS; log-rank = 13.554, P = 0.0001) CD44 expression (PFS; log-rank = 14.942, P = 0.0001, OS; log-rank = 20.986, P = 0.0001) remained significant prognostic factor for PFS and OS. In multivariate survival analysis, at step 1, only CD44 remained independent prognosticator for PFS (HR = 11.014, 95% CI = 2.256–23.602, P = 0.001) and OS (HR = 8.553, 95% CI = 2.831–25.847, P = 0.0001). In relation to treatment offered, patients with strong CD44 expression and if treated with surgery followed by adjuvant radiotherapy showed a high incidence of death (log-rank = 13.402, P = 0.0001) as compared to patients treated with surgery only. Receiver operating characteristic (ROC) curves also confirmed a good efficacy of CD44 as a prognosticator for disease outcome (PFS; P = 0.0001, OS; P = 0001). Conclusion Our overall findings addressed that a study of CD44 protein expression would be beneficiated to meningioma patients from unnecessary overtreatment and drug-induced toxicity. Also, CD44 could be one of the promising biomarkers that might differentiate high-risk meningioma patients for better treatment management.

Background/Aims: In our study, the effect of hyaluronan synthase 2 (HAS2) and CD44 immunoreactivity as a predictive biomarker in the prediction of progesterone-resistant endometrial hyperplasia (EH) cases without atypia was investigated. Settings and Design: In this retrospective study, HAS2 and CD44 immunoreactivity in the endometrial tissues of 60 patients diagnosed with EH and treated with progesterone and 20 patients diagnosed with proliferative endometrium (PE) were evaluated. Materials and Methods: Eighty patients were divided into four groups. Group 1 (G1) (n = 20) = PE group, G2 (n = 20) = EH group without atypia, G3 (n = 20) = group with continued EH with treatment, G4 (n = 20) = EH with treatment without atypia. Statistical Analysis: Intergroup evaluation was done with One-way ANOVA and posthoc tukey test. P < 0.05 values were considered statistically significant. Results: The HAS2 immunoreactivity score of G2 and G3 was higher than G1 and G4. On the other hand, there was no difference between G1 and G4. When G2 and G3 were compared, HAS2 immunoreactivity scores were significantly increased in G3. When CD44 immunoreactivity was compared with G1, a significant increase was detected in G2, G3, and G4. However, CD44 immunoreactivity scores were similar in G2, G3, and G4. Conclusion: HAS2 immunoreactivity may be an immunohistochemical biomarker in predicting EH cases without atypia resistant to progesterone therapy. Since CD44 immunoreactivity is increased in all EH groups without atypia, it is not effective in predicting treatment resistance.

Background: In India, breast cancer forms the most common malignancy, accounting for 28.2% of all female cancers. Breast cancer consists of phenotypically diverse group of diseases. Due to different relapse abilities, doubling times, and different infiltrative capacities, it is important to identify potential biomarkers that could be used to screen high-risk patient and predict breast cancer prognosis in conjunction with classical pathological parameters. Aims and Objectives: The present study was conducted to evaluate immunohistochemical expression of CD44 in breast carcinoma and to correlate CD44 expression with other clinicopathological parameters and molecular classification of carcinoma breast. Materials and Methods: The present study was a prospective descriptive study conducted on 100 cases of carcinoma breast diagnosed on modified radical mastectomy specimens that were submitted to the Department of Pathology, Pt. B. D. Sharma, PGIMS, Rohtak, Haryana, over the period of 2 years. Results: Out of 100, 64 cases (64%) were CD44 positive. Out of these 64 cases, 9 (9%) cases were 1+, 34 (34%) cases were 2+, and 21 (21%) cases showed 3+ positive expression of CD44 in tumor cells. Loss of CD44 expression was seen in 36 (36%) cases. A statistically significant association of CD44 was seen with multifocality of the tumor, negative estrogen receptor/progesterone receptor (ER/PR) expression, and molecular subtypes. No statistically significant association of CD44 was seen with age, side of tumor, lymph node metastasis, lymphovascular invasion, ductal carcinoma in situ and Ki67, and HER2neu expression. Conclusion: A high CD44 expression in breast carcinoma correlates with aggressive tumor characteristics such as multifocality, negative ER/PR expression, and belonging to the basal subtype which is associated with poor prognosis. Conversely, low CD44 expression is linked to Luminal A and Luminal B subtypes which have good prognosis. These indicate the role of CD44 as a prognostic biomarker in the carcinoma breast.

Abstract Tumour immunity is highly important for the occurrence and development of tumours, and many cancers are resistant to ferroptosis. This study aims to explore the relationship between ferroptosis-related genes (FRGs) and the immunological characteristics of kidney renal clear cell carcinoma (KIRC). We obtained RNA-seq profiles and clinical data of KIRC patients from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases and identified CD44 and GLRX5 as the key FRGs involved in KIRC immune infiltration through Spearman’s correlation analysis. Based on the expression of CD44 and GLRX5, the consensus clustering algorithm was used to classify the TCGA-KIRC samples into two clusters. A nomogram was constructed to evaluate the prognosis of KIRC patients. ESTIMATE, CIBERSORT, and single-sample gene set enrichment analysis (ssGSEA) were performed to evaluate immune infiltration between the two clusters. A weighted gene co-expression network analysis (WGCNA) was used to identify the most relevant genes to the clusters and immunity. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed. The external dataset GSE53757 was used to validate the immunological features between the two clusters. Cluster 2 patients had more active immune infiltration and might be more sensitive to immunotherapy; Cluster 2 patients also had a worse prognosis and might be at a more advanced stage of KIRC. We identified key ferroptosis-related genes and subgroups involved in the immune infiltration of KIRC, which is highly important for exploring the molecular mechanisms and treatments of KIRC.

One of the modern approaches to the treatment of cancer is the creation of targeted delivery systems for anticancer drugs, which allows increasing the concentration of the delivered substance in the right place and preventing its accumulation in healthy organs and tissues. At the same time, one can also expect an increase in the duration and effectiveness of the drugs, as well as a reduction in side effects during therapy. The hyaluronic acid receptor CD44, which, according to the literature, is highly expressed in many types of tumors and regulates metastasis, is a promising target for targeted delivery of anticancer drugs. The purpose of this study was to evaluate the effect of a supramolecular delivery system based on hyaluronic acid with nanosized cavitand cyclodextrin on the antitumor properties of oxaliplatin in vitro. Cell lines 1301, SK-MEL-28 and B16 were used as tumor cells. Cells were cultured in the presence of a delivery system based on hyaluronic acid (HACD), oxaliplatin (OX), and their complex (HACD-OX) at various concentrations in complete culture medium RPMI-1640 containing 0.3% L-glutamine, 4% gentamicin and 10% inactivated FBS serum for 48 hours in a humidified atmosphere of 5% CO2 at 37°C. The effect of the studied compounds on the viability of cell cultures was assessed using the WST test. It was shown that in the case of the T-cell lymphoma cell line 1301, the HACD delivery system did not affect the ability of OX to reduce the viability of tumor cells of this line; the effect of free oxaliplatin and the complex was comparable. However, in the case of melanoma cells (B16 and SK-MEL-28), the HACD-DOX complex has a more pronounced antitumor effect, causing a statistically significant decrease in the viability of B16 and SK-MEL-28 cells compared to free oxaliplatin.

Abstract Retinitis pigmentosa (RP), an inherited retinal disease, affects 1,5 million people worldwide. The initial mutation-driven photoreceptor degeneration leads to chronic inflammation, characterized by Müller cell activation and upregulation of CD44. CD44 is a cell surface transmembrane glycoprotein and the primary receptor for hyaluronic acid. It is involved in many pathological processes, but little is known about CD44’s retinal functions. CD44 expression is also increased in Müller cells from our Pde6b STOP/STOP RP mouse model. To gain a more detailed understanding of CD44’s role in healthy and diseased retinas, we analyzed Cd44 −/− and Cd44 −/− Pde6b STOP/STOP mice, respectively. The loss of CD44 led to enhanced photoreceptor degeneration, reduced retinal function, and increased inflammatory response. To understand the underlying mechanism, we performed proteomic analysis on isolated Müller cells from Cd44 −/− and Cd44 −/− Pde6b STOP/STOP retinas and identified a significant downregulation of glutamate transporter 1 (SLC1A2). This downregulation was accompanied by higher glutamate levels, suggesting impaired glutamate homeostasis. These novel findings indicate that CD44 stimulates glutamate uptake via SLC1A2 in Müller cells, which in turn, supports photoreceptor survival and function.

Introduction: CD44 is a transmembrane glycoprotein implicated in tissue inflammation and fibrosis. We investigated its role in kidney inflammation and fibrosis in a murine model of lupus nephritis (LN), and the clinico-pathological association of serum CD44 level in patients with biopsy-proven Class III/IV ± V LN. Methods: NZB/W F1 mice were treated with control IgG or anti-CD44 monoclonal antibody for 4 weeks and disease parameters assessed. Serum CD44 level in LN patients was determined by ELISA. Control groups included healthy subjects and patients with non-renal SLE or non-lupus renal disease. Results: CD44 expression was absent in the normal kidney, but it was expressed in proximal and distal tubular epithelial cells and infiltrating cells in renal biopsies from patients with active proliferative LN. ScRNA-Seq datasets confirmed that CD44 was predominantly expressed in tubular cells and all immune cells identified in LN patients including tissue resident, inflammatory and phagocytic macrophages, Treg cells, effector and central memory CD4+ T cells, resident memory CD8+ T cells and naïve and activated B cells. Treatment of NZB/W F1 mice with anti-CD44 antibody preserved kidney histology and reduced proteinuria, tubulo-interstitial infiltration of CD3+, CD4+ and CD19+ immune cells, and mediators of kidney fibrosis compared to Control mice. Longitudinal studies showed that serum CD44 level increased prior to clinical renal flare by 4.5 months and the level decreased after treatment. ROC curve analysis showed that CD44 level distinguished patients with active LN from healthy subjects and patients with quiescent LN, active non-renal lupus, and non-lupus CKD (ROC AUC of 0.99, 0.96, 0.99 and 0.99 respectively). CD44 level correlated with leukocyte infiltration and interstitial inflammation scores in active LN kidney biopsies. Discussion: Our findings suggest that CD44 plays a pathogenic role in renal parenchymal inflammation and fibrosis in active LN and monitoring CD44 may facilitate early diagnosis of flare. [ABSTRACT FROM AUTHOR]

The article "Corrigendum: Exosomal CD44 transmits lymph node metastatic capacity between gastric cancer cells via YAP-CPT1A-mediated FAO reprogramming" published in Frontiers in Oncology on October 11, 2024, addresses errors in Figures 1E, 3C, and 4L-M, which were corrected due to image pasting mistakes. The authors conducted repeat experiments for Figure 3C and found consistent results with the original findings. The scientific conclusions of the article remain unchanged despite these errors, and the original article has been updated accordingly. [Extracted from the article]

Background: Lymph node metastasis (LNM) commonly occurs in gastric cancer (GC) and is tightly associated with poor prognosis. Exosome-mediated lymphangiogenesis has been considered an important driver of LNM. Whether exosomes directly transmit the LNM phenotype between GC cells and its mechanisms remain elusive. Methods: A highly lymphatic metastatic GC cell line (HGC-27-L) was established by serial passage of parental HGC-27 cells in BALB/c nude mice. The capacities of migration, invasion and LNM; fatty acid oxidation (FAO) levels; and the role of exosome-transferred LNM phenotype were compared among HGC-27-L, HGC-27 and primary GC cell line AGS. Exosomes derived from GC cells and sera were separately isolated using ultracentrifugation and ExoQuick exosome precipitation solution, and were characterized by transmission electron microscopy, Nanosight and western blotting. Transwell assay and LNM models were conducted to evaluate the capacities of migration, invasion and LNM of GC cells in vitro and in vivo. b-oxidation rate and CPT1 activity were measured to assess FAO. CPT1A inhibitor etomoxir was used to determine the role of FAO. Label-free LC-MS/MS proteome analysis screened the differential protein profiling between HGC-27-exosomes and AGS-exosomes. Small interference RNAs and YAP inhibitor verteporfin were used to elucidate the role and mechanism of exosomal CD44. TCGA data analysis, immunochemistry staining and ELISA were performed to analyze the expression correlation and clinical significance of CD44/YAP/CPT1A. Results: FAO was increased in lymphatic metastatic GC cells and indispensable for sustaining LNM capacity. Lymphatic metastatic GC cell-exosomes conferred LNM capacity on primary GC cells in an FAO-dependent way. Mechanistically, CD44 was identified to be enriched in HGC-27-exosomes and was a critical cargo protein regulating exosome-mediated transmission, possibly by modulating the RhoA/YAP/Prox1/CPT1A signaling axis. Abnormal expression of CD44/YAP/CPT1A in GC tissues was correlated with each other and associated with LNM status, stages, invasion and poor survival. Serum exosomal CD44 concentration was positively correlated with tumor burden in lymph nodes. Conclusions: We uncovered a novel mechanism: exosomal CD44 transmits LNM capacity between GC cells via YAP-CPT1A-mediated FAO reprogramming from the perspective of exosomes-transferred LNM phenotype. This provides potential therapeutic targets and a non-invasive biomarker for GC patients with LNM. [ABSTRACT FROM AUTHOR]

Background: Lung cancer is recognized as one of the leading causes of cancer-related deaths globally, with a significant increase in incidence and intricate pathogenic mechanisms. This study examines the expression profiles of Programmed Cell Death Protein 1 (PD-1), PD-1 ligand (PDL-1), β-catenin, CD44, interleukin 6 (IL-6), and interleukin 10 (IL-10), as well as their correlations with the clinic-pathological features and diagnostic significance in lung cancer patients. Methods and results: The research involved lung cancer patients exhibiting various pathological characteristics, alongside demographically matched healthy controls. The expression levels of PD-1, PDL-1, β-catenin, and CD44 were analyzed using Real-Time PCR, while circulating levels of IL-6 and IL-10 were assessed through ELISA assays. This investigation focused on peripheral blood mononuclear cells (PBMC) to evaluate these factors non-invasively. Findings indicated that levels of PD-1, PDL-1, and CD44 were significantly elevated in patients compared to controls, which coincided with a decrease in β-catenin levels. Additionally, a concurrent rise in IL-6 and IL-10, both pro-inflammatory cytokines, was observed in patients, suggesting a potential regulatory role for these cytokines on the PD-1/PDL-1 axis, which may help tumors evade immune system checkpoints. The predictive value of these factors concerning lung tumors and metastasis was significant (Regression analysis). Furthermore, these markers demonstrated diagnostic potential in differentiating between patients and healthy controls, as well as between individuals with metastatic and non-metastatic tumors (ROC curve analysis). Conclusions: This study provides insights into the expression profiles of PD-1/PDL-1 immune system checkpoints and their regulatory factors in lung cancer, potentially paving the way for new therapeutic and diagnostic approaches. [ABSTRACT FROM AUTHOR]

AIM: To explore the molecular mechanism by which leukemia inhibitory factor （LIF） enhances the stemness characteristics of colorectal cancer （CRC） cells by regulating the expression of the molecular marker CD44 in cancer stem cells （CSCs）. METHODS: The expression of LIF in CRC tissues was analyzed using the TCGA public database and RNAscope in situ hybridization method. Stable knockdown of LIF was constructed in CRC cell lines （HCT116 and Caco2 cells） using a lentiviral infection system. The experiment was divided into 4 groups: CRC cells control group, CRC cells plus LIF group, CRC cells knockdown control group, and CRC cells knockdown LIF group. The impact of exogenous LIF on CRC cells' capacity for spheroidization was assessed through stem cell spheroidization assays. The ability of CRC cells to proliferate and migrate was evaluated using MTT, RTCA, plate cloning, and migration tests following the addition or removal of LIF. The impact of LIF on the expression of the transcription factor ELF3 and CD44 in CRC tumor cells was determined using RT-qPCR, a fully automated protein expression analysis system, and Western blot. RT-qPCR was used to identify changes in CD44 splicing variant expression following LIF knockdown. RESULTS: The results demonstrated that the expression level of LIF in CRC tissue was higher than that in neighboring cancer tissue （P<0. 01）, and that patients with CRC who had high expression of LIF had a shorter disease-free survival time （P<0. 05）. While LIF knockdown can decrease CRC cells' capability to proliferate and migrate （P<0. 05）, exogenous LIF can boost CRC cells' sphericity, proliferation, and migration capacity （P<0. 05）. Exogenous LIF can raise （P<0. 05） CD44 expression in CRC tumor cells, however LIF reduction can lower （P<0. 01） CD44 expression and lower the transcription level of CD44 splicing variants. Exogenous injection of LIF or LIF knockdown can cause a significant change （P<0. 05） in the expression level of the transcription factor ELF3. CONCLUSION: LIF improves the stemness characteristics of colorectal cancer cells by upregulating the transcription factor ELF3, which also promotes the development of malignancy by increasing CD44 expression in CRC cells. [ABSTRACT FROM AUTHOR]

Background/Objectives: Conventional anticancer therapies often lack specificity, targeting both cancerous and normal cells, which reduces efficacy and leads to undesired off-target effects. An additional challenge is the presence of hypoxic regions in tumors, where the Hypoxia Inducible Factor (HIF) transcriptional system drives the expression of pro-survival and drug resistance genes, leading to radio- and chemo-resistance. This study aims to explore the efficacy of targeted nanoparticle (NP)-based small interfering RNA (siRNA) therapies in downregulating these genes to enhance treatment outcomes in pancreatic cancer, a tumor type characterized by high CD44 expression and hypoxia. Methods: We utilized hyaluronic acid (HA)-displaying nanoparticles composed of positively charged chitosan (CS) complexed with siRNA to target and knock down HIF-1α in pancreatic cancer cells. Two NP formulations were prepared using either low molecular weight (LMW) or high molecular weight (HMW) CS. These formulations were evaluated for their internalization by cells and their effectiveness in gene silencing, both in vitro and in vivo. Results: The study found that the molecular weight (MW) of CS influenced the interaction between HA and CD44, as well as the release of siRNA upon internalization. The LMW CS formulation shows faster uptake kinetics, while HMW CS is more effective in gene knockdown across different cell lines in vitro. In vivo, both were able to significantly knockdown HIF-1α and some of its downstream genes. Conclusions: The results suggest that HMW and LMW CS-based NPs exhibit distinct characteristics, showing that both MWs have potential for targeted pancreatic cancer therapy by influencing different aspects of delivery and gene silencing, particularly in the hypoxic tumor microenvironment. [ABSTRACT FROM AUTHOR]

Although progress has been made in the treatment of cancer, particularly for the four major types of cancers affecting the lungs, colon, breast and prostate, resistance to cancer treatment often emerges upon inhibition of major signaling pathways, which leads to the activation of additional pathways as a last-resort survival mechanism by the cancer cells. This signaling plasticity provides cancer cells with a level of operational freedom, reducing treatment efficacy. Plasticity is a characteristic of cancer cells that are not only able to switch signaling pathways but also from one cellular state (differentiated cells to stem cells or vice versa) to another. It seems implausible that the inhibition of one or a few signaling pathways of heterogeneous and plastic tumors can sustain a durable effect. We propose that inhibiting molecules with pleiotropic functions such as cell surface co-receptors can be a key to preventing therapy escape instead of targeting bona fide receptors. Therefore, we ask the question whether co-receptors often considered as "accessory molecules" are an overlooked key to control cancer cell behavior. [ABSTRACT FROM AUTHOR]

Objectives: Cancer cells with 'stemness' are generally resistant to chemoradiotherapy. This study aims to compare the differences in radiation sensitivity of A549 and CD44+A549 stem-like cells to X-rays and carbon ion radiation (C-ions), and to find a target that can kill cancer stem-like cells (CSCs) of non-small cell lung cancer (NSCLC). Methods: The study used two cell lines (A549 and CD44+A549). The tumorigenicity of cells was tested with animal experiments. The cells were irradiated with X-rays and C-ions. Cell viability was detected using the CCK-8 and EdU assay. A liquid chromatograph-mass spectrometer (LC–MS) helped detect metabolic differences. Protein and mRNA expression were detected using a Western blot, reverse transcription-quantitative (RT-qPCR), and PCR array. The autophagic activity was monitored with a CYTO-ID® Autophagy Detection Kit 2.0. Immunofluorescence and co-immunoprecipitation helped to observe the localization and interaction relationships. Results: First, we verified the radio-resistance of CD44+A549 stem-like cells. LC-MS indicated the difference in autophagy between the two cells, followed by establishing a correlation between the radio-resistance and autophagy. Subsequently, the PCR array proved that TGM2 is significantly upregulated in CD44+A549 stem-like cells. Moreover, the TGM2 knockdown by small interfering RNA could decrease the radio-resistance of CD44+A549 cells. Bioinformatic analyses and experiments showed that TGM2 is correlated with the expression of CD44 and LC3B. Additionally, TGM2 could directly interact with LC3B. Conclusions: We established the CD44-TGM2-LC3 axis: CD44 mediates radio-resistance of CD44+A549 stem-like cells through TGM2 regulation of autophagy. Our study may provide new biomarkers and strategies to alleviate the radio-resistance of CSCs in NSCLC. [ABSTRACT FROM AUTHOR]

Tumour immunity is highly important for the occurrence and development of tumours, and many cancers are resistant to ferroptosis. This study aims to explore the relationship between ferroptosis-related genes (FRGs) and the immunological characteristics of kidney renal clear cell carcinoma (KIRC). We obtained RNA-seq profiles and clinical data of KIRC patients from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases and identified CD44 and GLRX5 as the key FRGs involved in KIRC immune infiltration through Spearman's correlation analysis. Based on the expression of CD44 and GLRX5, the consensus clustering algorithm was used to classify the TCGA-KIRC samples into two clusters. A nomogram was constructed to evaluate the prognosis of KIRC patients. ESTIMATE, CIBERSORT, and single-sample gene set enrichment analysis (ssGSEA) were performed to evaluate immune infiltration between the two clusters. A weighted gene co-expression network analysis (WGCNA) was used to identify the most relevant genes to the clusters and immunity. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed. The external dataset GSE53757 was used to validate the immunological features between the two clusters. Cluster 2 patients had more active immune infiltration and might be more sensitive to immunotherapy; Cluster 2 patients also had a worse prognosis and might be at a more advanced stage of KIRC. We identified key ferroptosis-related genes and subgroups involved in the immune infiltration of KIRC, which is highly important for exploring the molecular mechanisms and treatments of KIRC. [ABSTRACT FROM AUTHOR]

Background: We investigated the expression of inflammation, placental development, and function markers, including cluster of differentiation 44 (CD44), osteopontin (OPN), and cyclooxygenase-2 (COX-2), to shed light on the controversy regarding the impact of the COVID-19 epidemic on fetal development and pregnancy outcomes. Methods: We immunohistochemically analyzed placental tissue from 170 patients (65 COVID-positive and unvaccinated women; 35 Pfeizer-vaccinated and COVID-negative women; and 70 COVID-negative and unvaccinated women, without any other associated pathology) for particularities in the expression of these three molecules. Results: CD44 expression was highest in COVID-negative and unvaccinated women, moderate in COVID-positive cases, and lowest in vaccinated and COVID-negative women. OPN expression was highest in COVID-negative and Pfeizer-vaccinated cases, moderate in COVID-negative and unvaccinated cases, and lowest in COVID-positive cases. COX-2 expression was increased in COVID-negative and unvaccinated women, modestly elevated in COVID-positive and unvaccinated cases, and lowest in vaccinated cases. Conclusions: These findings reflected an alteration in the placental structure and consequent function due to altered expression of the three studied molecules. [ABSTRACT FROM AUTHOR]

While tyrosine kinase inhibitor resistance in cancer is a critical issue in the medical field, it is important for clinical testing as well, since it affects the ultimate outcome of cancer therapy. Yet, no effective solutions have been implemented till date. Clinical observations after tyrosine kinase inhibitor treatment reveal that acquired resistance inevitably limits the curative effects of non-small cell lung cancer treatment because of mutations in the epidermal growth factor receptor gene, which are accompanied by epithelial-mesenchymal transition. Here, for the first time, we report that the transmembrane glycoprotein CD44, which is associated with epithelial-mesenchymal transition, chemoresistance, and cancer progression, mediates enhanced endocytosis of iron-platinum alloy nanoparticles (FePt NPs) in the mesenchymal-state gefitinib-resistant (GR+ and M6) cells, via the binding of the CD44 ligand, hyaluronan, to the surface-absorbed hyaluronan-binding protein 2. Upon treatment with FePt NPs, there was higher cellular uptake in mesenchymal-state GR+ and M6 cells, resulting from cell death through ferroptosis and mitochondrial dysfunction, as compared to that observed in the epithelial-state cells. Mechanistically, inactivation of dihydroorotate dehydrogenase elevated the production of mitochondrial lipid peroxidation, and enhanced the cell death in the epithelial-state HCC827 cells, thereby indicating its role in defense against FePt NPs-induced ferroptosis. Furthermore, induction of ferroptosis has been shown to specifically promote the cell death of drug-tolerant "persister" cells and reverse their resistance as well. Therefore, we concluded that FePt NPs preferentially target mesenchymal drug-tolerant "persister" cells and promote ferroptosis, to overcome their resistance. In the present study, we identified FePt NPs as an innovative agent for cancer treatment, particularly in mesenchymal-state cells that exhibit TKI resistance. Mesenchymal-state cancer cells showed enhanced uptake of FePt NPs via CD44-HA-mediated endocytosis, accompanied by severe cell death and mitochondrial morphology alterations, in comparison to epithelial-state cells. We further elucidated the mechanism underlying FePt NPs-induced ferroptotic cell death as via a burst of mitochondrial LPO and DHODH protein inactivation. In addition, we found that FePt NPs inhibit tumor growth in TKI-resistant mesenchymal GR+ cell-bearing mice with better efficacy than the ferroptotic inducer RSL3. Our current findings on using FePt NPs to overcome TKI resistance through ferroptosis activation may offer a alternative strategy for improved cancer treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: In India, breast cancer forms the most common malignancy, accounting for 28.2% of all female cancers. Breast cancer consists of phenotypically diverse group of diseases. Due to different relapse abilities, doubling times, and different infiltrative capacities, it is important to identify potential biomarkers that could be used to screen high-risk patient and predict breast cancer prognosis in conjunction with classical pathological parameters. Aims and Objectives: The present study was conducted to evaluate immunohistochemical expression of CD44 in breast carcinoma and to correlate CD44 expression with other clinicopathological parameters and molecular classification of carcinoma breast. Materials and Methods: The present study was a prospective descriptive study conducted on 100 cases of carcinoma breast diagnosed on modified radical mastectomy specimens that were submitted to the Department of Pathology, Pt. B. D. Sharma, PGIMS, Rohtak, Haryana, over the period of 2 years. Results: Out of 100, 64 cases (64%) were CD44 positive. Out of these 64 cases, 9 (9%) cases were 1+, 34 (34%) cases were 2+, and 21 (21%) cases showed 3+ positive expression of CD44 in tumor cells. Loss of CD44 expression was seen in 36 (36%) cases. A statistically significant association of CD44 was seen with multifocality of the tumor, negative estrogen receptor/progesterone receptor (ER/PR) expression, and molecular subtypes. No statistically significant association of CD44 was seen with age, side of tumor, lymph node metastasis, lymphovascular invasion, ductal carcinoma in situ and Ki67, and HER2neu expression. Conclusion: A high CD44 expression in breast carcinoma correlates with aggressive tumor characteristics such as multifocality, negative ER/PR expression, and belonging to the basal subtype which is associated with poor prognosis. Conversely, low CD44 expression is linked to Luminal A and Luminal B subtypes which have good prognosis. These indicate the role of CD44 as a prognostic biomarker in the carcinoma breast. [ABSTRACT FROM AUTHOR]

At the time of colorectal cancer (CRC) diagnosis, approximately 25% of patients present with liver metastases, and 70% develop them during follow-up. This is the primary cause of therapeutic failure and most associated deaths, making it imperative to understand the molecular mechanisms involved in this process and the biological components involved. In the process of anaerobic glycolysis occurring in these cells, to maintain cellular homeostasis, excess lactate is removed via monocarboxylate transporters (MCTs). This study aimed to characterize monocarboxylate transporter 4 (MCT4), human glucose transporter protein isoform 1(GLUT1), cluster of differentiation 147 (CD147), and the acidic cell surface adhesion protein (CD44) in various cellular and histological compartments of liver metastases from CRC in 45 patients diagnosed with metastatic CRC. The characterization revealed significant correlations between the compartmentalization of these markers and the patients' clinicopathological data. The findings for MCT4, GLUT1, CD147, and CD44 obtained in this study are very promising in relation to considering these markers as therapeutic targets in further investigations. [ABSTRACT FROM AUTHOR]

Retinitis pigmentosa (RP), an inherited retinal disease, affects 1,5 million people worldwide. The initial mutation-driven photoreceptor degeneration leads to chronic inflammation, characterized by Müller cell activation and upregulation of CD44. CD44 is a cell surface transmembrane glycoprotein and the primary receptor for hyaluronic acid. It is involved in many pathological processes, but little is known about CD44's retinal functions. CD44 expression is also increased in Müller cells from our Pde6bSTOP/STOP RP mouse model. To gain a more detailed understanding of CD44's role in healthy and diseased retinas, we analyzed Cd44−/− and Cd44−/−Pde6bSTOP/STOP mice, respectively. The loss of CD44 led to enhanced photoreceptor degeneration, reduced retinal function, and increased inflammatory response. To understand the underlying mechanism, we performed proteomic analysis on isolated Müller cells from Cd44−/− and Cd44−/−Pde6bSTOP/STOP retinas and identified a significant downregulation of glutamate transporter 1 (SLC1A2). This downregulation was accompanied by higher glutamate levels, suggesting impaired glutamate homeostasis. These novel findings indicate that CD44 stimulates glutamate uptake via SLC1A2 in Müller cells, which in turn, supports photoreceptor survival and function. [ABSTRACT FROM AUTHOR]