Inhibition of hyaluronan degradation by dextran sulphate facilitates characterisation of hyaluronan synthesis: an in vitro and in vivo study

Colorectal cancer-associated ~ 6 kDa hyaluronan serves as a novel biomarker for cancer progression and metastasis

Low molecular weight hyaluronan (LMW-HA) is believed to accumulate in tumors and to exert protumor effects. This study aimed to identify colorectal cancer (CRC)-associated LMW-HA, precisely determine its MW, and elucidate its role in predicting tumor progression. The MW distribution of HA extracted from CRC and paired noncancerous tissues was evaluated. We found that the level of HA with a MW below 30 kDa was markedly elevated in CRC tissues, and we defined HA with a MW of ~ 6 kDa as CRC-associated LMW-HA. In line with this finding, ~ 6 kDa HA was significantly accumulated in cancer tissues relative to total HA, and this LMW-HA played a critical role in tumor metastasis. Moreover, serum ~ 6 kDa HA levels in CRC patients were significantly increased and positively correlated with the levels in matched cancer tissues. Elevated serum ~ 6 kDa HA levels could be used to discriminate patients with or without CRC and was associated with early relapse, advanced tumor-node-metastasis stage, lymphovascular invasion, and lymph node (LN) metastasis. Notably, serum ~ 6 kDa HA levels were significantly reduced after tumor resection. Our study suggests that ~ 6 kDa HA may serve as a new biomarker for estimating tumor progression, predicting LN metastasis, and monitoring tumor recurrence.

Emerging roles for hyaluronidase in cancer metastasis and therapy

Hyaluronidases are a family of five human enzymes that have been differentially implicated in the progression of many solid tumor types, both clinically and in functional studies. Advances in the past 5 years have clarified many apparent contradictions: (1) by demonstrating that specific hyaluronidases have alternative substrates to hyaluronan (HA) or do not exhibit any enzymatic activity, (2) that high-molecular weight HA polymers elicit signaling effects that are opposite those of the hyaluronidase-digested HA oligomers, and (3) that it is actually the combined overexpression of HA synthesizing enzymes with hyaluronidases that confers tumorigenic potential. This review examines the literature supporting these conclusions and discusses novel mechanisms by which hyaluronidases impact invasive tumor cell processes. In addition, a detailed structural and functional comparison of the hyaluronidases is presented with insights into substrate selectivity and potential for therapeutic targeting. Finally, technological advances in targeting hyaluronidase for tumor imaging and cancer therapy are summarized.

A novel role of low molecular weight hyaluronan in breast cancer metastasis

Low molecular weight hyaluronan (LMW-HA), a degradation fragment of the extracellular matrix component hyaluronan (HA), has been proven to play a crucial role in cancer progression. However, no systematic clinical study of breast cancer has been performed to correlate LMW-HA levels with metastasis. In the present study, we analyzed 176 serum specimens and found for the first time that the serum LMW-HA (but not total HA) level significantly correlated with lymph node metastasis, suggesting that serum LMW-HA represents a better prognostic indicator of breast cancer progression than HA. Similarly, we found that breast cancer cell lines displaying higher invasive potential had a higher LMW-HA concentration than less-invasive cell lines. This higher LMW-HA level was accompanied by the overexpression of hyaluronan synthase (HAS2) and hyaluronidase (both HYAL1 and HYAL2). Of great importance, decreasing LMW-HA production significantly inhibited breast cancer cell migration and invasion. Overall, our results suggest that during cancer progression, cancer cells may actively remodel their microenvironment via an autocrine/paracrine-like process, resulting in elevated LMW-HA levels, which in turn may facilitate cancer progression by promoting the migration and invasion of cancer cells. Therefore, cancer-associated LMW-HA may be a more promising molecular biomarker than total HA for detecting metastasis and may have further applications in breast cancer treatment.

Development of a novel metastatic breast cancer score based on hyaluronic acid metabolism

Tumor metastasis involves the dissemination of malignant cells into the basement membrane, and the vascular system contributes to the circulating pool of these markers. In this context, our aim has been focused on the development of a non-invasive score based on degradation of the backbone of glycosaminoglycans of the extracellular matrix; namely hyaluronic acid (HA), for the assessment of metastasis in patients with breast cancer. HA level was determined by enzyme-linked immunosorbent assay; CA 15.3 was determined by microparticle enzyme immunoassay; hyaluronidase, N-acetyl-β-D-glucosaminidase, β-glucuronidase, glucuronic acid, and glucosamine were assayed by standard colorimetric techniques in 217 patients with breast cancer. Statistical analyses were performed by logistic regression and receiver-operating characteristic analysis curves. The multivariate discriminant analysis selects a score based on absolute values of the six biochemical markers: metastatic breast cancer score (MBCS) = [1.04 (Numerical constant) + 0.003 × CA 15.3 (U/l) + 0.001 × HA (ng/ml) + 0.004 × hyaluronidase (mg N-acetyl-β-D-glucosamine/ml/18 h) + 0.001 × N-acetyl-β-D-glucosaminidase (μmol/ml/min) + 0.026 × glucuronic acid (ng/ml) + 0.003 × glucosamine (μg/dl)]. This function correctly classified 87 % of metastatic breast cancer at cut-off value = 0.85 (i.e., great than 0.85 indicates patients with metastatic breast cancer and less than 0.85 indicates patients with non-metastatic breast cancer). MBCS is a novel, non-invasive, and simple score which can be applied to discriminate patients with metastatic breast cancer.

Upregulation of HYAL1 expression in breast cancer promoted tumor cell proliferation, migration, invasion and angiogenesis

Hyaluronic acid (HA) is a component of the Extra-cellular matrix (ECM), it is closely correlated with tumor cell growth, proliferation, metastasis and angiogenesis, etc. Hyaluronidase (HAase) is a HA-degrading endoglycosidase, levels of HAase are elevated in many cancers. Hyaluronidase-1 (HYAL1) is the major tumor-derived HAase. We previously demonstrated that HYAL1 were overexpression in human breast cancer. Breast cancer cells with higher HAase expression, exhibited significantly higher invasion ability through matrigel than those cells with lower HAase expression, and knockdown of HYAL1 expression in breast cancer cells resulted in decreased cell growth, adhesion, invasion and angiogenesis. Here, to further elucidate the function of HYAL1 in breast cancer, we investigated the consequences of forcing HYAL1 expression in breast cancer cells by transfection of expression plasmid. Compared with control, HYAL1 up-regulated cells showed increased the HAase activity, and reduced the expression of HA in vitro. Meantime, upregulation of HYAL1 promoted the cell growth, migration, invasion and angiogenesis in vitro. Moreover, in nude mice model, forcing HYAL1 expression induced breast cancer cell xenograft tumor growth and angiogenesis. Interestingly, the HA expression was upregulated by forcing HYAL1 expression in vivo. These findings suggested that HYAL1-HA system is correlated with the malignant behavior of breast cancer.

HYAL1 overexpression is correlated with the malignant behavior of human breast cancer

Extracellular matrix (ECM) is closely correlated with tumor cell growth, proliferation, metastasis and angiogenesis, etc. Hyaluronic acid (HA) is a component of the ECM, and hyaluronidase (HAase) is a HA-degrading endoglycosidase. Levels of HAase are elevated in many cancers. Hyaluronidase-1 (HYAL1) is the major tumor-derived HAase. In this study, we detected HYAL1 expression levels in breast cancer cells and tissues, and measured the amount HAase activity in breast cancer cells. Compared with nonmalignant breast cell line HBL-100 and normal breast tissues, HYAL1 were overexpressed in breast cancer cell lines MDA-MB-231, MCF-7, invasive duct cancer tissues and metastatic lymph nodes, respectively. Accordingly, the amount HAase activity in MDA-MB-231 and MCF-7 was higher than that in HBL-100. In addition, knockdown of HYAL1 expression in MDA-MB-231 and MCF-7 cells resulted in decreased cell growth, adhesion, invasion and angiogenesis potential. Meantime, the HYAL1 knockdown markedly inhibited breast cancer cell xenograft tumor growth and microvessel density. Further studies showed that the HYAL1, HYAL2 and HA were elevated in breast cancer, and HYAL1 could downregulate HA expression. In conclusion, HYAL1 may be a potential prognostic marker and therapeutic target in breast cancer.

Polyinosine-polycytidylic acid stimulates versican accumulation in the extracellular matrix promoting monocyte adhesion

Viral infections are known to exacerbate asthma and other lung diseases in which chronic inflammatory processes are implicated, but the mechanism is not well understood. The viral mimetic, polyinosine-polycytidylic acid, causes accumulation of a versican- and hyaluronan-enriched extracellular matrix (ECM) by human lung fibroblasts with increased capacity for monocyte adhesion. The fivefold increase in versican retention in this ECM is due to altered compartmentalization, with decreased degradation of cell layer-associated versican, rather than an increase in total accumulation in the culture. This is consistent with decreased mRNA levels for all of the versican splice variants. Reduced versican degradation is further supported by low levels of the epitope, DPEAAE, a product of versican digestion by a disintegrin-like and metallopeptidase with thrombospondin type 1 motif enzymes, in the ECM. The distribution of hyaluronan is similarly altered with a 3.5-fold increase in the cell layer. Pulse-chase studies of radiolabeled hyaluronan show a 50% reduction in the rate of loss from the cell layer over 24 hours. Formation of monocyte-retaining, hyaluronidase-sensitive ECMs can be blocked by the presence of anti-versican antibodies. In comparison, human lung fibroblasts treated with the cytokines, IL-1beta plus TNF-alpha, synthesize increased amounts of hyaluronan, but do not retain it or versican in the ECM, which, in turn, does not retain monocytes. These results highlight an important role for versican in the hyaluronan-dependent binding of monocytes to the ECM of lung fibroblasts stimulated with polyinosine-polycytidylic acid.

Regulation of hyaluronan and versican deposition by growth factors in fibrosarcoma cell lines

Versican, a large chondroitin sulphate proteoglycan and hyaluronan (HA), a non-sulphated glycosaminoglycan are major constituents of the pericellular matrix. In many neoplastic tissues, changes in the expression of versican and HA affect tumour progression. Here, we analyse the synthesis of versican and hyaluronan by fibrosarcoma cells, and document how the latter is affected by PDGF-BB, bFGF and TGFB2, growth factors endogenously produced by these cells. Fibrosarcoma cell lines B6FS and HT1080 were utilised and compared with normal lung fibroblasts (DLF). The major versican isoforms expressed by DLF and B6FS cells were V0 and V1. Treatment of B6FS cells with TGFB2 showed a significant increase of V0 and V1 mRNAs. Versican expression in HT1080 cells was not significantly affected by any of the growth factors. In addition, TGFB2 treatment increased versican protein in DLF cells. HA, showed approximately a 2-fold and a 9-fold higher production in DLF cells compared to B6FS and HT1080 cells, respectively. In HT1080 cells, HA biosynthesis was significantly increased by bFGF, whereas, in B6FS cells it was increased by TGFB2 and PDGF-BB. Furthermore, analysis of HA synthases (HAS) expression indicated that HT1080 expressed similar levels of all three HAS isoforms in the following order: HAS2> HAS3> HAS1. bFGF shifted that balance by increasing the abundance of HAS1. The major HAS isoform expressed by B6FS cells was HAS2. PDGF-BB and TGFB2 showed the most prominent effects by increasing both HAS2 and HAS1 isoforms. In conclusion, these growth factors modulated, through upregulation of specific HAS isoforms, HA synthesis, secretion and net deposition to the pericellular matrix.

The over-expression of HAS2, Hyal-2 and CD44 is implicated in the invasiveness of breast cancer

Within tumors there appears to be an intricate balance between hyaluronan (HA) synthesis and degradation where the invading edges display increased HA metabolism. The metabolism of HA has not been characterized in breast cancer cell lines; therefore, this study quantitatively identifies and characterizes the enzymes responsible for the synthesis and degradation of HA while correlating gene expression to cancer cell invasiveness and HA receptor status. In ten well-established breast cancer cell lines, the expression of the genes for each hyaluronan synthase (HAS) and hyaluronidase (Hyal) isoform was quantitated using real-time and reverse transcriptase polymerase chain reaction (PCR). The synthesis and degradation rates of hyaluronan were determined by ELISA, while quantitation of HA receptors, CD44 and RHAMM was performed by comparative Western blotting. The molecular weight of HA synthesized by each HAS isoform and the degradation products of each hyaluronidase were characterized by size exclusion chromatography. It was demonstrated that highly invasive cell lines preferentially expressed the HAS2 and Hyal-2 isoforms, while less invasive cells expressed HAS3 and Hyal-3. There was a correlation between elevated levels of HA synthesis, CD44 expression and cancer cell migration thereby highlighting the pivotal role that HA metabolism plays in the aggressive breast cancer phenotype.

Antisense-Mediated Suppression of Hyaluronan Synthase 2 Inhibits the Tumorigenesis and Progression of Breast Cancer

The progression of several cancers is correlated with the increased synthesis of the glycosaminoglycan, hyaluronan. Hyaluronan is synthesized at the plasma membrane by various isoforms of hyaluronan synthases (HAS). The importance of HAS2 expression in highly invasive breast cancer was characterized by the antisense inhibition of HAS2 (ASHAS2). The effect of HAS2 inhibition on cell proliferation, migration, hyaluronan metabolism, and receptor status was characterized in vitro, whereas the effect on tumorigenicity and metastasis was established in vivo. HAS2 inhibition resulted in a 24-hour lag in proliferation that was concomitant to transient arrest of 79% of the cell population in G0-G1. Inhibition of HAS2 did not alter the expression of the other HAS isoforms, whereas hyaluronidase (HYAL2) and the hyaluronan receptor, CD44, were significantly down-regulated. ASHAS2 cells accumulated greater amounts of high molecular weight hyaluronan (>10,000 kDa) in the culture medium, whereas mock and parental cells liberated less hyaluronan of three distinct molecular weights (100, 400, and 3,000 kDa). The inhibition of HAS2 in the highly invasive MDA-MB-231 breast cancer cell line inhibited the initiation and progression of primary and secondary tumor formation following s.c. and intracardiac inoculation into nude mice, whereas controls readily established both primary and secondary tumors. The lack of primary and secondary tumor formation was manifested by increased survival times where ASHAS2 animals survived 172% longer than the control animals. Collectively, these unique results strongly implicate the central role of HAS2 in the initiation and progression of breast cancer, potentially highlighting the co-dependency between HAS2, CD44, and HYAL2 expression.