Soluble CD44 secretion contributes to the acquisition of aggressive tumor phenotype in human colon cancer cells

High prevalence of CD44 and its ligand low molecular weight hyaluronan in plasma of HNSCC patients: clinical significance

BACKGROUND

This study aims to evaluate the role of cancer stem cell marker, CD44, and its ligand HA as potential molecular biomarker for early detection of HNSCC.

METHODS AND RESULTS

The expression profile (mRNA/Protein) of CD44 variants were analysed in primary HNSCC lesions and plasma of the patients. Then, prevalence of HA variants was analysed in plasma of the patients. The mRNA expression of CD44 variants, CD44S and CD44v3, were significantly high in both early (stage I/II) and late (stage III/IV) invasive lesions, with predominant expression of CD44v3 in the late-stage lesions. In plasma of HNSCC patients, increased levels of SolCD44, CD44-ICD and unique 62 KD CD44 variants with respect to standard CD44S were seen, in comparison to their prevalence in plasma of normal individuals. The abundance of CD44-ICD and 62 KD variants were significantly high in plasma of late stage HNSCC patients. Interestingly, significantly high level of low molecular weight HA(LMW HA) with respect to high molecular weight HA(HMW HA) was seen in plasma of HNSCC patients irrespective of clinical stages. On the contrary, high HMW HA level in plasma of normal individuals was seen. The high level of LMW HA in plasma of HNSCC patients might be due to combinatorial effect of increased mRNA expression of HA synthesizing enzyme HAS1/2/3 and HA degrading enzyme HYAL1/2, as seen in the primary HNSCC samples.

CONCLUSION

Thus, our data revealed the importance of specific CD44 and HA variants in plasma of HNSCC patients during its development as potential non-invasive molecular biomarker of the disease.

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.

Bromelain a Potential Bioactive Compound: A Comprehensive Overview from a Pharmacological Perspective

Bromelain is an effective chemoresponsive proteolytic enzyme derived from pineapple stems. It contains several thiol endopeptidases and is extracted and purified via several methods. It is most commonly used as an anti-inflammatory agent, though scientists have also discovered its potential as an anticancer and antimicrobial agent. It has been reported as having positive effects on the respiratory, digestive, and circulatory systems, and potentially on the immune system. It is a natural remedy for easing arthritis symptoms, including joint pain and stiffness. This review details bromelain's varied uses in healthcare, its low toxicity, and its relationship to nanoparticles. The door of infinite possibilities will be opened up if further extensive research is carried out on this pineapple-derived enzyme.

CD44 splice variant (CD44v3) promotes progression of urothelial carcinoma of bladder through Akt/ERK/STAT3 pathways: novel therapeutic approach

PURPOSE

The incidence of Urothelial carcinoma of bladder (UBC) is gradually increasing by changing lifestyle and environment. The development of a tumor has been noted to be accompanied by modifications in the extracellular matrix (ECM) consisting of CD44, hyaluronic acid (HA) and its family members. The importance of CD44 splice variants and HA family members has been studied in UBC.

METHODS

The cohort of study included 50 UBC patients undergoing radical cystectomy and 50 healthy subjects. The molecular expression of CD44 and HA family members was determined. Effect of CD44 variant-specific silencing on downstream signaling in HT1376 cells was investigated. Combinatorial treatment of 4-MU (4-methylumbelliferone) with cisplatin or doxorubicin on chemosensitivity was also explored.

RESULTS

Higher expression of HA, HAS2, and CD44 was observed in Indian UBC patients which also showed the trend with severity of disease. Splice variant assessment of CD44 demonstrated the distinct role of CD44v3 and CD44v6 in bladder cancer progression. shRNA-mediated downregulation of CD44v3 showed an increase effect on cell cycle, apoptosis and multiple downstream signaling cascade including pAkt, pERK and pSTAT3. Furthermore, 4-MU, an HA synthesis inhibitor, observed to complement the effect of Cisplatin or Doxorubicin by enhancing the chemosensitivity of bladder cancer cells.

CONCLUSIONS

Our findings exhibit involvement of CD44 splice variants and HA family members in UBC and significance of 4-MU in enhancing chemosensitivity suggesting their novel therapeutic importance in disease therapeutics.

Longevity effect of a polysaccharide from Chlorophytum borivilianum on Caenorhabditis elegans and Saccharomyces cerevisiae

The traditional Indian medicine, Ayurveda, provides insights and practical solutions towards a healthy life style. Rasayana is a branch of Ayurveda known for preserving and promoting health, enhancing the quality of life and delaying the aging process. In the traditional knowledge, the Rasayana herb, Chlorophytum borivilianum (C. borivilanum) is regarded as a general health promoting tonic that delays aging and increases lifespan, cognitive function and physical strength. Aging is a complex and multifactorial physiological phenomenon that manifests itself over a wide range of biological systems, tissues, and functions. Longevity is an obvious marker of physiological aging. Simple model systems such as the single-cell budding yeast Saccharomyces cerevisiae (S. cerevisiae) and the nematode, Caenorhabditis elegans (C. elegans) are widely used to study the aging process and longevity. Here, we show that a polysaccharide fraction obtained from C. borivilianum increases the lifespan of S. cerevisiae and C. elegans, using an automated screening platform (Chronoscreen^TM). Chemical analysis of this extract revealed a low molecular weight polysaccharide of 1000 Da, predominantly comprising Glu1→6Glu linkage. This polysaccharide showed significant dose-dependent extension of the median lifespan of S. cerevisiae by up to 41% and of the median lifespan of C. elegans by up to 10%. Taking cue from these results and the traditionally described benefits of Rasayanas on skin rejuvenation, we tested in vitro the polysaccharide for potential skin benefits. In a keratinocyte culture, we observed that this polysaccharide increased cell proliferation significantly, and induced synthesis of hyaluronic acid (HA), a well-known extracellular matrix component. Furthermore, when added to culture medium of human reconstructed epidermis, we observed an enhanced production of epidermal markers, e.g. CD44 and HA that are otherwise diminished in aged skin. Together, these results suggest that in addition to life-span extension of S. cerevisiae and C. elegans, a polysaccharide from the Rasayana herb, C. borivilianum may have beneficial effects on skin aging parameters.

Potential role of bromelain in clinical and therapeutic applications

Pineapple has been used as part of traditional folk medicine since ancient times and it continues to be present in various herbal preparations. Bromelain is a complex mixture of protease extracted from the fruit or stem of the pineapple plant. Although the complete molecular mechanism of action of bromelain has not been completely identified, bromelain gained universal acceptability as a phytotherapeutic agent due to its history of safe use and lack of side effects. Bromelain is widely administered for its well-recognized properties, such as its anti-inflammatory, antithrombotic and fibrinolytic affects, anticancer activity and immunomodulatory effects, in addition to being a wound healing and circulatory improvement agent. The current review describes the promising clinical applications and therapeutic properties of bromelain.

Tumour Microenvironment: Overview with an Emphasis on the Colorectal Liver Metastasis Pathway

The tumour microenvironment (TME) represents a dynamic network that plays an important role in tumour initiation, proliferation, growth, and metastasis. Cell behaviour may be regulated by interplay of molecular interactions involving positive and negative reinforcement as well as a high level of cross-talk, which determines this system. Additionally, cancer involves cell proliferation, its malignancy defined by the tumour's ability to break down normal tissue architecture and by a dynamic process of invasion and metastasis. The metastatic cascade is regulated by a chain of molecular steps which triggers the progression of the developing cancer cell in the primary tumour into a number of transformations, leading to invasion and proceeding to metastases. Tumour-associated macrophages (TAMs) play a key-role in the progression from inflammatory conditions to cancer; TAMs are also capable of infiltrating the tumour microenvironment. Furthermore, myeloid-derived suppressor cells (MDSCs), a population of inhibitory immune cells, have been reported to increase in various cancer types, although characterising human MDSCs remains difficult, as their phenotype is quite variable. The future of cancer treatment is likely to involve creating more drugs that target these elements as well as others. An overview of the tumour's microenvironment is, therefore, presented in this paper, focusing on the metastatic pathways of primary colorectal cancer to the liver.

The engagement of selectins and their ligands in colorectal cancer liver metastases

The colonization of the liver by colorectal cancer (CRC) cells is a complicated process which includes many stages, until macrometastases occur. The entrapment of malignant cells within the hepatic sinusoids and their interactions with resident non-parenchymal cells are considered very important for the whole metastatic sequence. In the sinusoids, cell connection and signalling is mediated by multiple cell adhesion molecules, such as the selectins. The three members of the selectin family, E-, P- and L-selectin, in conjunction with sialylated Lewis ligands and CD44 variants, regulate colorectal cell communication and adhesion with platelets, leucocytes, sinusoidal endothelial cells and stellate cells. Their role in CRC liver metastases has been investigated in animal models and human tissue, in vivo and in vitro, in static and shear flow conditions, and their key-function in several molecular pathways has been displayed. Therefore, trials have already commenced aiming to exploit selectins and their ligands in the treatment of benign and malignant diseases. Multiple pharmacological agents have been developed that are being tested for potential therapeutic applications.

Aging-related alterations in the extracellular matrix modulate the microenvironment and influence tumor progression

Age is the greatest risk factor for the development of epithelial cancers. In this minireview, we will examine key extracellular matrix and matricellular components, their changes with aging, and discuss how these alterations might influence the subsequent progression of cancer in the aged host. Because of the tight correlation between advanced age and the prevalence of prostate cancer, we will use prostate cancer as the model throughout this minireview.

Soluble adhesion molecules in human cancers: sources and fates

Adhesion molecules endow tumor cells with the necessary cell-cell contacts and cell-matrix interactions. As such, adhesion molecules are involved in cell signalling, proliferation and tumor growth. Rearrangements in the adhesion repertoire allow tumor cells to migrate, invade and form metastases. Besides these membrane-bound adhesion molecules several soluble adhesion molecules are detected in the supernatant of tumor cell lines and patient body fluids. Truncated soluble adhesion molecules can be generated by several conventional mechanisms, including alternative splicing of mRNA transcripts, chromosomal translocation, and extracellular proteolytic ectodomain shedding. Secretion of vesicles (ectosomes and exosomes) is an alternative mechanism mediating the release of full-length adhesion molecules. Soluble adhesion molecules function as modulators of cell adhesion, induce proteolytic activity and facilitate cell signalling. Additionally, adhesion molecules present on secreted vesicles might be involved in the vesicle-target cell interaction. Based on currently available data, released soluble adhesion molecules contribute to cancer progression and therefore should not be regarded as unrelated and non-functional side products of tumor progression.

Bromelain's activity and potential as an anti-cancer agent: Current evidence and perspectives

The medicinal qualities of pineapple are recognized in many traditions in South America, China and Southeast Asia. These qualities are attributed to bromelain, a 95%-mixture of proteases. Medicinal qualities of bromelain include anti-inflammatory, anti-thrombotic, fibrinolytic and anti-cancer functions. Existing evidence derived from clinical observations as well as from mouse- and cell-based models suggests that bromelain acts systemically, affecting multiple cellular and molecular targets. In recent years, studies have shown that bromelain has the capacity to modulate key pathways that support malignancy. It is now possible to suggest that the anti-cancer activity of bromelain consists in the direct impact on cancer cells and their micro-environment, as well as in the modulation of immune, inflammatory and haemostatic systems. This review will summarize existing data relevant to bromelain's anti-cancer activity and will suggest mechanisms which account for bromelain's effect, in the light of research involving non-cancer models. The review will also identify specific new research questions that will need to be addressed in order for a full assessment of bromelain-based anti-cancer therapy.

Evaluation of CD44 and CD44v6 in colorectal carcinoma patients: soluble forms in relation to tumor tissue expression and metastasis

INTRODUCTION

It has been shown that CD44 may be associated with poor prognosis in various human malignancies. This study was designed to investigate and compare the prognostic relevance and clinical value of soluble forms of CD44 and its variant v6 (CD44v6) and their tissue expression in colorectal carcinoma.

MATERIALS AND METHODS

Serum levels of pre- and postoperative CD44 and CD44v6 molecules were evaluated in 37 colorectal cancer patients and compared to healthy individuals.

RESULTS AND DISCUSSION

The serum levels of soluble CD44 and CD44v6 showed no significant decrease after surgical resection of the tumor (p = 0.5). Both CD44 and CD44v6 serum levels either before or after surgery were significantly higher in patients than in normal individuals (p < 0.001). The serum level of CD44v6 molecule was higher in patients with lymph node metastasis than other patients (p = 0.05) implying the role of this molecule in tumor progression. Immunohistochemical staining showed expression of CD44 in 14.3% and CD44v6 in 42.9% of the tumor samples. The expression of CD44v6 was associated with metastatic involvement of lymph nodes (p = 0.03). CD44v6 expression was positively correlated with its level in the serum of patients (p = 0.04).

CONCLUSIONS

Results of this study showed that CD44v6 expression level either in the soluble form or in the cell membrane is associated with tumor metastasis indicating the importance of this molecule in progression of colorectal carcinoma. The serum levels of soluble CD44 as well as CD44v6 might be useful markers for tumor screening.

Anticancer therapeutics: targeting macromolecules and nanocarriers to hyaluronan or CD44, a hyaluronan receptor

The complex system involved in the synthesis, degradation and binding of the high molecular weight glycosaminoglycan hyaluronic acid (hyaluronan or HA) provides a variety of structures that can be exploited for targeted cancer therapy. In many cancers of epithelial origin there is an upregulation of CD44, a receptor that binds HA. In other cancers, HA in the tumor matrix is overexpressed. Both CD44 on cancer cells and HA in the matrix have been targets for anticancer therapy. Even though CD44 is expressed in normal epithelial cells and HA is part of the matrix of normal tissues, selective targeting to cancer is possible. This is because macromolecular carriers predominantly extravasate into the tumor and not normal tissue; thus CD44-HA targeted carriers administered intravenously localize preferentially into tumors. Anti-CD44 antibodies have been used in patients to deliver radioisotopes or mertansine for treatment of CD44 expressing tumors. In early phase clinical trials, patients with breast or head and neck tumors treated with anti-CD44 conjugates experienced stabilized disease. A dose-limiting toxicity was associated with distribution of the antibody-drug conjugate to the skin, a site in the body with a high level of CD44. HA has been used as a drug carrier and a ligand on liposomes or nanoparticles to target drugs to CD44 overexpressing cells. Drugs can be attached to HA via the carboxylate on the glucuronic acid residue, the hydroxyl on the N-acetylglucosamine or the reducing end which are located on a repeating disaccharide. Drugs delivered in HA-modified liposomes exhibited excellent antitumor activity both in vitro and in murine tumor models. The HA matrix is also a potential target for anticancer therapies. By manipulating the interaction of HA with cell surface receptors, either by degrading it with hyaluronidase or by interfering with CD44-HA interactions using soluble CD44 proteins, tumor progression was blocked. Finally, cytotoxic drugs or prodrug converting enzymes can be attached to the HA matrix to generate a cytotoxic fence around the tumor. This review describes how the complex interplay among cancer biology, the CD44-HA interaction, drug carriers and drug targeting has been used to improve anticancer therapies. As these approaches evolve, they hold forth the prospect of significantly improved targeted anticancer treatments.

Role of cancer microenvironment in metastasis: focus on colon cancer

One person on three will receive a diagnostic of cancer during his life. About one third of them will die of the disease. In most cases, death will result from the formation of distal secondary sites called metastases. Several events that lead to cancer are under genetic control. In particular, cancer initiation is tightly associated with specific mutations that affect proto-oncogenes and tumour suppressor genes. These mutations lead to unrestrained growth of the primary neoplasm and a propensity to detach and to progress through the subsequent steps of metastatic dissemination. This process depends tightly on the surrounding microenvironment. In fact, several studies support the point that tumour development relies on a continuous cross-talk between cancer cells and their cellular and extracellular microenvironments. This signaling cross-talk is mediated by transmembrane receptors expressed on cancer cells and stromal cells. The aim of this manuscript is to review how the cancer microenvironment influences the journey of a metastatic cell taking liver invasion by colorectal cancer cells as a model.