Hyaluronan-CD44 interaction promotes microRNA signaling and RhoGTPase activation leading to tumor progression

Hyaluronan-CD44 Interaction Regulates Mouse Retinal Progenitor Cells Migration, Proliferation and Neuronal Differentiation

Cell-based therapies have shown great potential because of their abilities to replace dying retinal neuron cells and preserve vision. The migration, proliferation and differentiation of retinal progenitor cells(RPCs) plays a vital role in the integration of the RPCs into the retina when transplanted into the host. Our study aimed to explore the effects of Hyaluronan(HA)-CD44 interactions on the regulation of RPCs migration, proliferation and differentiation, and investigate the underlying regulatory mechanisms. We found that CD44 was expressed in RPCs, and the HA-CD44 interaction markedly improved RPCs adhesion and migration. The stimulation of microRNA-21(miR-21) expression by the HA-CD44 interaction was protein kinase C (PKC)/Nanog-dependent in RPCs. Treatment of RPCs with PKC- or Nanog-specific ASODN or miR-21 antagomir effectively blocked HA-mediated RPCs adhesion and migration. Moreover, Rho-Kinase(ROK)/ Grb2-associated binders(Gab-1) associated phosphatidylinositol 3-kinase(PI3K)/AKT signalling activation was required for HA-CD44 interaction mediated RPCs proliferation and neuronal differentiation. Our findings demonstrated new roles for the HA-CD44 interaction in regulating the migration, proliferation and neuronal differentiation of RPCs. HA-CD44 signalling could represent a novel approach to controlling RPC fates, and the findings may be instructive for the application of RPCs for future therapeutic applications.

Hyaluronan Receptors as Mediators and Modulators of the Tumor Microenvironment

The tumor microenvironment (TME) is a dynamic and complex matter shaped by heterogenous cancer and cancer-associated cells present at the tumor site. Hyaluronan (HA) is a major TME component that plays pro-tumorigenic and carcinogenic functions. These functions are mediated by different hyaladherins expressed by cancer and tumor-associated cells triggering downstream signaling pathways that determine cell fate and contribute to TME progression toward a carcinogenic state. Here, the interaction of HA is reviewed with several cell-surface hyaladherins-CD44, RHAMM, TLR2 and 4, LYVE-1, HARE, and layilin. The signaling pathways activated by these interactions and the respective response of different cell populations within the TME, and the modulation of the TME, are discussed. Potential cancer therapies via targeting these interactions are also briefly discussed.

Non-invasive diagnostic potential of microRNA-203 in liquid biopsy of urothelial carcinoma of bladder

Increased CD44 antigen activity has been reported in recurrent cases of UBC. To date, no reliable biomarker is available with high significance and specificity for non-invasive detection of UBC. This study aimed to identify a CD44-linked microRNAs (miRNAs) (miR-9, miR-34a, miR-203) for non-invasive diagnosis of bladder cancer from other urinary tract malignancies. The expression of CD44-linked miRNAs was examined in serum, urine, and tissue specimens of Indian UBC patients (N = 25). For this purpose, healthy subjects (N = 25) and benign prostatic hyperplasia (BPH) (N = 10) patients were taken as controls. The relative expression of miRNAs was analyzed in serum, urine, and tissue samples using real-time quantitative reverse transcription PCR (qRT-PCR). The diagnostic potential of these miRNAs was accessed by plotting ROC curve. Increased miR-9 expression was observed in serum of UBC patients than healthy and BPH controls. In UBC patients, miR-34a expression was lower than healthy controls but non-significant as compared to BPH. miR-203 expression was considerably higher in serum of UBC patients but non-significant as compared to BPH controls. miR-203 was found to be considerably higher in urine samples from UBC patients as compared to BPH and healthy controls. The diagnostic potential of these miRNAs was evaluated using the ROC curve. Higher miR-203 levels in the urine of Indian UBC patients demonstrate its non-invasive diagnostic ability out of the three miRNAs studied. Our results characterize the non-invasive diagnostic potential of CD44-linked miR-203 in the urine of Indian UBC patients, which could be utilized in clinical settings in future after validation in larger patient cohort.

Enhanced migration of engrafted retinal progenitor cells into the host retina via disruption of glial barriers

Purpose

Migration and integration remain critical challenges for stem cell replacement therapy. Glial barriers play an important role in preventing cell migration and integration. The purpose of this study was to investigate the effect and mechanisms of chondroitinase ABC on the migration of murine retinal progenitor cells (mRPCs) transplanted into the subretinal space of B6 mice.

Methods

mRPCs were harvested from the neural retinas of P1 enhanced green fluorescent protein (GFP) B6 mice. Two μl containing 2 × 10⁵ expanded RPCs alone or combined with chondroitinase ABC in suspension were injected into the subretinal space of the recipient B6 mice. Immunohistochemistry was performed on the recipient B6 retinas to evaluate the glial barrier formation and migration of the mRPCs. Western blotting was also used to check the expression of the glial barriers.

Results

Glial fibrillary acidic protein (GFAP) and vimentin could be seen around the transplanted mRPCs in the B6 mice. Formation of glial barriers prevented the migration of donor cells into the retinal layers. Chondroitinase ABC promoted the migration and survival rates of the engrafted retinal progenitor cells in the retinal layers of recipient B6 mice. Injection induced upregulation of GFAP, chondroitin, and CD44 expression. Chondroitinase ABC disrupted the glial barriers. The CD44 around the mRPCs was much lower in the chondroitinase group. However, the CD44 in the retinal layers was considerably higher in the chondroitinase group. With the employment of chondroitinase ABC, more cells migrated into the outer nuclear layer or inner nuclear layer. The chondroitin and CD44 expression decreased 3 weeks after transplantation in the chondroitinase ABC group.

Conclusions

Chondroitinase ABC degraded glial barriers and enhanced the migration of transplanted mouse retinal progenitor cells. Chondroitinase ABC may also have induced activation of the CD44 signaling pathway to exert the effect.

Abuhamad A, Syahir A. Understanding Glioblastoma Biomarkers: Knocking a Mountain with a Hammer

Gliomas are the most frequent and deadly form of human primary brain tumors. Among them, the most common and aggressive type is the high-grade glioblastoma multiforme (GBM), which rapidly grows and renders patients a very poor prognosis. Meanwhile, cancer stem cells (CSCs) have been determined in gliomas and play vital roles in driving tumor growth due to their competency in self-renewal and proliferation. Studies of gliomas have recognized CSCs via specific markers. This review comprehensively examines the current knowledge of the most significant CSCs markers in gliomas in general and in glioblastoma in particular and specifically focuses on their outlook and importance in gliomas CSCs research. We suggest that CSCs should be the superior therapeutic approach by directly targeting the markers. In addition, we highlight the association of these markers with each other in relation to their cascading pathways, and interactions with functional miRNAs, providing the role of the networks axes in glioblastoma signaling pathways.

Tunicamycin induces ER stress and inhibits tumorigenesis of head and neck cancer cells by inhibiting N-glycosylation

Glycosylation plays an important role in the genesis of various cancers. The inhibition of glycosylation disturbs the protein folding machinery, causing the accumulation of unfolded proteins in the cell endoplasmic reticulum (ER) and inducing ER stress. Tunicamycin (TM) is an inhibitor of glycosylation that has shown marked antitumor activity. In this study, we investigated the effect of TM on the tumorigenesis of head and neck cancer cells. The effects of TM on cell proliferation, colony formation and tumorsphere formation in vitro and tumorigenicity in vivo were investigated in head and neck cancer cells. ER stress was determined by the evaluation of PERK, PDI, IRE1-α, BIP, Ero1-Lα and calnexin expression using western blotting and immunofluorescence. We found that TM inhibited colony formation and tumorsphere formation of head and neck cancer cells in vitro and suppressed tumor growth in vivo. After incubation with TM, the expression of the cancer stem cell markers CD44 and Bmi-1 was reduced, and the expression of the ER stress markers BIP, Ero1-Lα and calnexin was elevated. Moreover, the EGFR signaling pathway was inhibited, and nonglycosylated EGFR degradation was accelerated with TM treatment. Our results suggest that inhibition of glycosylation by TM may be a novel treatment strategy for use with HNSCC patients.

Matrix Hyaluronan-CD44 Interaction Activates MicroRNA and LncRNA Signaling Associated With Chemoresistance, Invasion, and Tumor Progression

Tumor malignancies involve cancer cell growth, issue invasion, metastasis and often drug resistance. A great deal of effort has been placed on searching for unique molecule(s) overexpressed in cancer cells that correlate(s) with tumor cell-specific behaviors. Hyaluronan (HA), one of the major ECM (extracellular matrix) components have been identified as a physiological ligand for surface CD44 isoforms which are frequently overexpressed in malignant tumor cells during cancer progression. The binding interaction between HA and CD44 isoforms often stimulates aberrant cellular signaling processes and appears to be responsible for the induction of multiple oncogenic events required for cancer-specific phenotypes and behaviors. In recent years, both microRNAs (miRNAs) (with ~20–25 nucleotides) and long non-coding RNAs (lncRNAs) (with ~200 nucleotides) have been found to be abnormally expressed in cancer cells and actively participate in numerous oncogenic signaling events needed for tumor cell-specific functions. In this review, I plan to place a special emphasis on HA/CD44-induced signaling pathways and the presence of several novel miRNAs (e.g., miR-10b/miR-302/miR-21) and lncRNAs (e.g., UCA1) together with their target functions (e.g., tumor cell migration, invasion, and chemoresistance) during cancer development and progression. I believe that important information can be obtained from these studies on HA/CD44-activated miRNAs and lncRNA that may be very valuable for the future development of innovative therapeutic drugs for the treatment of matrix HA/CD44-mediated cancers.

Cancer-on-a-chip for Drug Screening

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The oncology pharmaceutical research spent a shocking amount of money on target validation and drug optimization in preclinical models because many oncology drugs fail during clinical trial phase III. One of the most important reasons for oncology drug failures in clinical trials may due to the poor predictive tool of existing preclinical models. Therefore, in cancer research and personalized medicine field, it is critical to improve the effectiveness of preclinical predictions of the drug response of patients to therapies and to reduce costly failures in clinical trials. Three dimensional (3D) tumor models combine micro-manufacturing technologies mimic critical physiologic parameters present in vivo, including complex multicellular architecture with multicellular arrangement and extracellular matrix deposition, packed 3D structures with cell–cell interactions, such as tight junctions, barriers to mass transport of drugs, nutrients and other factors, which are similar to in vivo tumor tissues. These systems provide a solution to mimic the physiological environment for improving predictive accuracy in oncology drug discovery.

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his review gives an overview of the innovations, development and limitations of different types of tumor-like construction techniques such as self-assemble spheroid formation, spheroids formation by micro-manufacturing technologies, micro-dissected tumor tissues and tumor organoid. Combination of 3D tumor-like construction and microfluidic techniques to achieve tumor on a chip for in vitro tumor environment modeling and drug screening were all included. Eventually, developmental directions and technical challenges in the research field are also discussed. We believe tumor on chip models have provided better sufficient clinical predictive power and will bridge the gap between proof-of-concept studies and a wider implementation within the oncology drug development for pathophysiological applications.

MicroRNAs for the pediatric otolaryngologist

The scope of pediatric otolaryngology is broad and encompasses a wide variety of diseases in which the fundamental phenotype-causing abnormality exists at the level of gene regulation and expression. Development of novel molecular biology instruments to diagnose disease, monitor treatment response, and prevent recurrence will facilitate the delivery of appropriate surgical and adjuvant medical treatments with lower morbidity. MicroRNAs (miRNAs) have emerged as a relatively new class of molecules that directly modulate gene expression and are abnormally expressed in a multitude of disease processes including those within the scope of pediatric otolaryngology. Functionally, miRNAs control multiple cellular functions including angiogenesis, cell proliferation, cell survival, genome stability, and inflammation. These short, non-protein coding RNA molecules are present and stable in tissue, blood, saliva, and urine, making them ideal disease biomarkers. The simple structure of miRNAs and their ability to directly modulate the expression of specific genes lends exciting therapeutic potential to miRNA-based therapies. Here we review the current literature of miRNAs as it relates to diseases within the scope of pediatric otolaryngology, and discuss their potential as diagnostic biomarkers and therapeutic targets.

Tunicamycin inhibits cell proliferation and migration in hepatocellular carcinoma through suppression of CD44s and the ERK1/2 pathway

Tunicamycin (TM) is an N‐linked glycosylation (NLG) inhibitor with strong antitumor activity, the exact underlying molecular mechanism of which remains to be elucidated. In our previous studies, we found that TM reversed drug resistance and improved the efficacy of combination treatments for hepatocellular carcinomas (HCC). Here, we investigated the effects of TM on HCC cell proliferation and migration as well as the mechanism of those effects. Our results showed that TM inhibited cell proliferation and migration as well as induced apoptosis of hepatocellular carcinoma cells. TM inhibited proliferation of HCC cells by inducing cell apoptosis and cell cycle arrest at the G2/M phase. Meanwhile, TM inhibited migration of HCC cells by suppressing CD44s‐mediated epithelial‐mesenchymal transition (EMT). TM inhibited migration and invasion of HCC cells by decreasing CD44 expression and altering its glycosylation. In addition, CD44s is involved in promoting EMT and is associated with a poor prognosis in HCC patients. Overexpression of CD44s promoted tumor migration and activated phosphorylation of ERK1/2 in HCC cells, whereas TM inhibited CD44s overexpression‐associated cell migration. The ability of TM to inhibit cell migration and invasion was enhanced or reversed in CD44s knockdown cells and cells overexpressing CD44s, respectively. The MEK/ERK inhibitor U0126 and TM inhibited hyaluronic acid‐induced cell migration in HCC cells. Furthermore, TM inhibited exogenous transforming growth factor beta (TGF‐β)‐mediated EMT by an ERK1/2‐dependent mechanism and restored the TGF‐β‐mediated loss of E‐cadherin. In summary, our study provides evidence that TM inhibits proliferation and migration of HCC cells through inhibition of CD44s and the ERK1/2 signaling pathway.

CD44 and its ligand hyaluronan as potential biomarkers in malignant pleural mesothelioma: evidence and perspectives

Malignant pleural mesothelioma (MPM) is a rare and highly drug resistant tumor arising from the mesothelial surfaces of the lung pleura. The standard method to confirm MPM is the tedious, time-consuming cytological examination of cancer biopsy. Biomarkers that are detectable in pleural effusion or patient serum are reasonable options to provide a faster and noninvasive diagnostic approach. As yet, the current biomarkers for MPM lack specificity and sensitivity to discriminate this neoplasm from other lung tumors. CD44, a multifunctional surface receptor has been implicated in tumor progression in different cancers including MPM. The interaction of CD44 with its ligand, hyaluronan (HA) has demonstrated an important role in modulating cell proliferation and invasiveness in MPM. In particular, the high expression levels of these molecules have shown diagnostic relevance in MPM. This review will summarize the biology and diagnostic implication of CD44 and HA as well as the interaction of both molecules in MPM that will demonstrate their potential as biomarkers. Augmentation of the current markers in MPM may lead to an earlier diagnosis and management of this disease.

Hyaluronan synthesis by developing cortical neurons in vitro

Hyaluronan is a linear glycosaminoglycan that forms the backbone of perineuronal nets around neurons in the cerebral cortex. However, it remains controversial whether neurons are capable of independent hyaluronan synthesis. Herein, we examined the expression of hyaluronan and hyaluronan synthases (HASs) throughout cortical neuron development in vitro. Enriched cultures of cortical neurons were established from E16 rats. Neurons were collected at days in vitro (DIV) 0 (4 h), 1, 3, 7, 14, and 21 for qPCR or immunocytochemistry. In the relative absence of glia, neurons exhibited HAS1–3 mRNA at all time-points. By immunocytochemistry, puncta of HAS2–3 protein and hyaluronan were located on neuronal cell bodies, neurites, and lamellipodia/growth cones from as early as 4 h in culture. As neurons matured, hyaluronan was also detected on dendrites, filopodia, and axons, and around synapses. Percentages of hyaluronan-positive neurons increased with culture time to ~93% by DIV21, while only half of neurons at DIV21 expressed the perineuronal net marker Wisteria floribunda agglutinin. These data clearly demonstrate that neurons in vitro can independently synthesise hyaluronan throughout all maturational stages, and that hyaluronan production is not limited to neurons expressing perineuronal nets. The specific structural localisation of hyaluronan suggests potential roles in neuronal development and function.

Pancreatic cancer stem cell markers and exosomes - the incentive push

Pancreatic cancer (PaCa) has the highest death rate and incidence is increasing. Poor prognosis is due to late diagnosis and early metastatic spread, which is ascribed to a minor population of so called cancer stem cells (CSC) within the mass of the primary tumor. CSC are defined by biological features, which they share with adult stem cells like longevity, rare cell division, the capacity for self renewal, differentiation, drug resistance and the requirement for a niche. CSC can also be identified by sets of markers, which for pancreatic CSC (Pa-CSC) include CD44v6, c-Met, Tspan8, alpha6beta4, CXCR4, CD133, EpCAM and claudin7. The functional relevance of CSC markers is still disputed. We hypothesize that Pa-CSC markers play a decisive role in tumor progression. This is fostered by the location in glycolipid-enriched membrane domains, which function as signaling platform and support connectivity of the individual Pa-CSC markers. Outside-in signaling supports apoptosis resistance, stem cell gene expression and tumor suppressor gene repression as well as miRNA transcription and silencing. Pa-CSC markers also contribute to motility and invasiveness. By ligand binding host cells are triggered towards creating a milieu supporting Pa-CSC maintenance. Furthermore, CSC markers contribute to the generation, loading and delivery of exosomes, whereby CSC gain the capacity for a cell-cell contact independent crosstalk with the host and neighboring non-CSC. This allows Pa-CSC exosomes (TEX) to reprogram neighboring non-CSC towards epithelial mesenchymal transition and to stimulate host cells towards preparing a niche for metastasizing tumor cells. Finally, TEX communicate with the matrix to support tumor cell motility, invasion and homing. We will discuss the possibility that CSC markers are the initial trigger for these processes and what is the special contribution of CSC-TEX.

Up-regulation of Histone Methyltransferase, DOT1L, by Matrix Hyaluronan Promotes MicroRNA-10 Expression Leading to Tumor Cell Invasion and Chemoresistance in Cancer Stem Cells from Head and Neck Squamous Cell Carcinoma

Human head and neck squamous cell carcinoma is a solid tumor malignancy associated with major morbidity and mortality. In this study, we determined that human head and neck squamous cell carcinoma-derived HSC-3 cells contain a subpopulation of cancer stem cells (CSCs) characterized by a high level of CD44v3 and aldehyde dehydrogenase-1 (ALDH1) expression. Importantly, matrix hyaluronan (HA) induces the up-regulation of stem cell markers that display the hallmark CSC properties. Histone methyltransferase, DOT1L, is also up-regulated by HA in CSCs (isolated from HSC-3 cells). Further analyses indicate that the stimulation of microRNA-10b (miR-10b) expression is DOT1L-specific and HA/CD44-dependent in CSCs. This process subsequently results in the overexpression of RhoGTPases and survival proteins leading to tumor cell invasion and cisplatin resistance. Treatment of CSCs with DOT1L-specific small interfering RNAs (siRNAs) effectively blocks HA/CD44-mediated expression of DOT1L, miR-10b production, and RhoGTPase/survival protein up-regulation as well as reduces tumor cell invasion and enhances chemosensitivity. CSCs were also transfected with a specific anti-miR-10b inhibitor to silence miR-10b expression and block its target functions. Our results demonstrate that the anti-miR-10 inhibitor not only decreases RhoGTPase/survival protein expression and tumor cell invasion, but also increases chemosensitivity in HA-treated CSCs. Taken together, these findings strongly support the contention that histone methyltransferase, DOT1L-associated epigenetic changes induced by HA play pivotal roles in miR-10 production leading to up-regulation of RhoGTPase and survival proteins. All of these events are critically important for the acquisition of cancer stem cell properties, including self-renewal, tumor cell invasion, and chemotherapy resistance in HA/CD44-activated head and neck cancer.

Niche Mimicking for Selection and Enrichment of Liver Cancer Stem Cells by Hyaluronic Acid-Based Multilayer Films

Cancer stem cells (CSCs) represent a subpopulation of tumor cells that exhibit capacities for self-renewal, tumor initiation, disease relapse or metastasis, and resistance to chemotherapy and radiotherapy. However, the major obstacle associated with the use of CSCs is the difficulty in their isolation and enrichment. According to recent studies, CSCs share similar properties with normal stem cells, and it has been observed that hyaluronan (HA) plays a key factor in CSCs niches and that HA-mediated CD44 interaction promotes tumor progression. Therefore, HA-based multilayer films were used to fabricate sequential surface properties variation and to mimic CSC niches. A quartz crystal microbalance was used to investigate the layer-by-layer adsorption of PAH/HA multilayer films. Colony formation was observed on a series of poly(allylamine hydrochloride) PAH/HA multilayer films, and cytotoxicity and cell viability were evaluated by MTT, LDH and live/dead assay. It was observed that the cells isolated from (PAH/HA)3 displayed the best colony formation ability and that the expression of CD133/CD44 double positive cells was up-regulated to approximately 70% after 7 days of culture. Furthermore, the cells isolated from (PAH/HA)3 displayed higher chemo-resistance than the control group. The stem-cell-related genes expression of selected cells from (PAH/HA)3 after 7 days of culture was significantly different from that of the control group. In conclusion, this study provides a label-free selection and enrichment system that could serve as a new strategy for the future development of CSC selection and drug evaluation in cancer therapy.

Selective Activation of Cancer Stem Cells by Size-Specific Hyaluronan in Head and Neck Cancer

We determined that human head and neck cancer cells (HSC-3 cell line) contain a subpopulation displaying cancer stem cell (CSC) properties and are very tumorigenic. Specifically, we investigated whether different sizes of hyaluronan (HA) (e.g., 5 kDa, 20 kDa, 200 kDa, or 700 kDa-HA-sizes) play a role in regulating these CSCs. First, we observed that 200 kDa-HA (but not other sizes of HA) preferentially induces certain stem cell marker expression resulting in self-renewal and clonal formation of these cells. Further analyses indicate that 200 kDa-HA selectively stimulates the expression of a panel of microRNAs (most noticeably miR-10b) in these CSCs. Survival protein (cIAP-1) expression was also stimulated by 200 kDa-HA in these CSCs leading to cisplatin resistance. Furthermore, our results indicate that the anti-miR-10 inhibitor not only decreases survival protein expression, but also increases chemosensitivity of the 200 kDa-HA-treated CSCs. These findings strongly support the contention that 200 kDa-HA plays a pivotal role in miR-10 production leading to survival protein upregulation and chemoresistance in CSCs. Together, our findings suggest that selective activation of oncogenic signaling by certain sizes of HA (e.g., 200 kDa-HA) may be instrumental in the formation of CSC functions leading to tumor cell survival and chemoresistance in head and neck cancer progression.

Hyaluronic acid promotes the expression of progesterone receptor membrane component 1 via epigenetic silencing of miR-139-5p in human and rat granulosa cells

Primary ovarian insufficiency (POI) is a serious reproductive dysfunction in which the follicle pool is reduced and depleted. Abnormal apoptosis of ovarian granulosa cells (GCs) is believed to result in follicle loss. Progesterone receptor membrane component 1 (PGRMC1), which is critical for GC survival, was reported to be reduced in POI patients, but the mechanism is unknown. In the present study, we found that PGRMC1 expression was correlated with the level of hyaluronic acid (HA) in POI patients. HA up-regulated PGRMC1 expression in GCs via suppression of miR-139-5p, which was proven by Western blotting and luciferase reporter assays to target PGRMC1. Consistent with these findings, levels of miR-139-5p were significantly increased and presented an inverse correlation with PGRMC1 in POI patients. Noticeably, HA inhibited CD44-mediated miR-139-5p expression but had no effect on luciferase activity after insertion of miR-139 promoter into luciferase plasmid. Interestingly, miR-139-5p was significantly up-regulated in KGN cells (GC tumor cell line) by the histone deacetylase inhibitor trichostatin A, indicating that HA down-regulated miR-139-5p expression via histone deacetylation. Taken together, we report an unrecognized mechanism of HA in the promotion of PGRMC1 expression, suggesting that HA may be a potential molecule for the prevention and treatment of POI.

Selective matrix (hyaluronan) interaction with CD44 and RhoGTPase signaling promotes keratinocyte functions and overcomes age-related epidermal dysfunction

BACKGROUND

Mouse epidermal chronologic aging is closely associated with aberrant matrix (hyaluronan, HA)-size distribution/production and impaired keratinocyte proliferation/differentiation, leading to a marked thinning of the epidermis with functional consequence that causes a slower recovery of permeability barrier function.

OBJECTIVE

The goal of this study is to demonstrate mechanism-based, corrective therapeutic strategies using topical applications of small HA (HAS) and/or large HA (HAL) [or a sequential small HA (HAS) and large HA(HAL) (HAs→HAL) treatment] as well as RhoGTPase signaling perturbation agents to regulate HA/CD44-mediated signaling, thereby restoring normal epidermal function, and permeability barrier homeostasis in aged mouse skin.

METHODS

A number of biochemical, cell biological/molecular, pharmacological and physiological approaches were used to investigate matrix HA-CD44-mediated RhoGTPase signaling in regulating epidermal functions and skin aging.

RESULTS

In this study we demonstrated that topical application of small HA (HAS) promotes keratinocyte proliferation and increases skin thickness, while it fails to upregulate keratinocyte differentiation or permeability barrier repair in aged mouse skin. In contrast, large HA (HAL) induces only minimal changes in keratinocyte proliferation and skin thickness, but restores keratinocyte differentiation and improves permeability barrier function in aged epidermis. Since neither HAS nor HAL corrects these epidermal defects in aged CD44 knock-out mice, CD44 likely mediates HA-associated epidermal functions in aged mouse skin. Finally, blockade of Rho-kinase activity with Y27632 or protein kinase-Nγ activity with Ro31-8220 significantly decreased the HA (HAS or HAL)-mediated changes in epidermal function in aged mouse skin.

CONCLUSION

The results of our study show first that HA application of different sizes regulates epidermal proliferation, differentiation and barrier function in aged mouse skin. Second, manipulation of matrix (HA) interaction with CD44 and RhoGTPase signaling could provide further novel therapeutic approaches that could be targeted for the treatment of various aging-related skin disorders.

Targeting treatment-resistant breast cancer stem cells with FKBPL and its peptide derivative, AD-01, via the CD44 pathway

PURPOSE

FK506-binding protein like (FKBPL) and its peptide derivative, AD-01, have already shown tumor growth inhibition and CD44-dependent antiangiogenic activity. Here, we explore the ability of AD-01 to target CD44-positive breast cancer stem cells (BCSC).

EXPERIMENTAL DESIGN

Mammosphere assays and flow cytometry were used to analyze the effect of FKBPL overexpression/knockdown and AD-01 treatment ± other anticancer agents on BCSCs using breast cancer cell lines (MCF-7/MDA-231/ZR-75), primary patient samples, and xenografts. Delays in tumor initiation were evaluated in vivo. The anti-stem cell mechanisms were determined using clonogenic assays, quantitative PCR (qPCR), and immunofluorescence.

RESULTS

AD-01 treatment was highly effective at inhibiting the BCSC population by reducing mammosphere-forming efficiency and ESA(+)/CD44(+)/CD24(-) or aldehyde dehydrogenase (ALDH)(+) cell subpopulations in vitro and tumor initiation in vivo. The ability of AD-01 to inhibit the self-renewal capacity of BCSCs was confirmed; mammospheres were completely eradicated by the third generation. The mechanism seems to be due to AD-01-mediated BCSC differentiation shown by a significant decrease in the number of holoclones and an associated increase in meroclones/paraclones; the stem cell markers, Nanog, Oct4, and Sox2, were also significantly reduced. Furthermore, we showed additive inhibitory effects when AD-01 was combined with the Notch inhibitor, DAPT. AD-01 was also able to abrogate a chemo- and radiotherapy-induced enrichment in BCSCs. Finally, FKBPL knockdown led to an increase in Nanog/Oct4/Sox2 and an increase in BCSCs, highlighting a role for endogenous FKBPL in stem cell signaling.

CONCLUSIONS

AD-01 has dual antiangiogenic and anti-BCSC activity, which will be advantageous as this agent enters clinical trial.