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Vlodavsky I, Hilwi M, Kayal Y, Soboh S, Ilan N. Impact of heparanase-2 (Hpa2) on cancer and inflammation: Advances and paradigms. FASEB J 2024; 38:e23670. [PMID: 38747803 DOI: 10.1096/fj.202400286r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 04/09/2024] [Accepted: 04/30/2024] [Indexed: 05/25/2024]
Abstract
HPSE2, the gene-encoding heparanase 2 (Hpa2), is mutated in urofacial syndrome (UFS), a rare autosomal recessive congenital disease attributed to peripheral neuropathy. Hpa2 lacks intrinsic heparan sulfate (HS)-degrading activity, the hallmark of heparanase (Hpa1), yet it exhibits a high affinity toward HS, thereby inhibiting Hpa1 enzymatic activity. Hpa2 regulates selected genes that promote normal differentiation, tissue homeostasis, and endoplasmic reticulum (ER) stress, resulting in antitumor, antiangiogenic, and anti-inflammatory effects. Importantly, stress conditions induce the expression of Hpa2, thus establishing a feedback loop, where Hpa2 enhances ER stress which, in turn, induces Hpa2 expression. In most cases, cancer patients who retain high levels of Hpa2 survive longer than patients bearing Hpa2-low tumors. Experimentally, overexpression of Hpa2 attenuates the growth of tumor xenografts, whereas Hpa2 gene silencing results in aggressive tumors. Studies applying conditional Hpa2 knockout (cHpa2-KO) mice revealed an essential involvement of Hpa2 contributed by the host in protecting against cancer and inflammation. This was best reflected by the distorted morphology of the Hpa2-null pancreas, including massive infiltration of immune cells, acinar to adipocyte trans-differentiation, and acinar to ductal metaplasia. Moreover, orthotopic inoculation of pancreatic ductal adenocarcinoma (PDAC) cells into the pancreas of Hpa2-null vs. wild-type mice yielded tumors that were by far more aggressive. Likewise, intravenous inoculation of cancer cells into cHpa2-KO mice resulted in a dramatically increased lung colonization reflecting the involvement of Hpa2 in restricting the formation of a premetastatic niche. Elucidating Hpa2 structure-activity-relationships is expected to support the development of Hpa2-based therapies against cancer and inflammation.
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Affiliation(s)
- Israel Vlodavsky
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Maram Hilwi
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Yasmin Kayal
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Soaad Soboh
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Neta Ilan
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
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2
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Hilwi M, Shulman K, Naroditsky I, Feld S, Gross-Cohen M, Boyango I, Soboh S, Vornicova O, Farhoud M, Singh P, Bar-Sela G, Goldberg H, Götte M, Sharrocks AD, Li Y, Sanderson RD, Ilan N, Vlodavsky I. Nuclear localization of heparanase 2 (Hpa2) attenuates breast carcinoma growth and metastasis. Cell Death Dis 2024; 15:232. [PMID: 38519456 PMCID: PMC10959965 DOI: 10.1038/s41419-024-06596-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 02/28/2024] [Accepted: 03/06/2024] [Indexed: 03/25/2024]
Abstract
Unlike the intense research effort devoted to exploring the significance of heparanase in cancer, very little attention was given to Hpa2, a close homolog of heparanase. Here, we explored the role of Hpa2 in breast cancer. Unexpectedly, we found that patients endowed with high levels of Hpa2 exhibited a higher incidence of tumor metastasis and survived less than patients with low levels of Hpa2. Immunohistochemical examination revealed that in normal breast tissue, Hpa2 localizes primarily in the cell nucleus. In striking contrast, in breast carcinoma, Hpa2 expression is not only decreased but also loses its nuclear localization and appears diffuse in the cell cytoplasm. Importantly, breast cancer patients in which nuclear localization of Hpa2 is retained exhibited reduced lymph-node metastasis, suggesting that nuclear localization of Hpa2 plays a protective role in breast cancer progression. To examine this possibility, we engineered a gene construct that directs Hpa2 to the cell nucleus (Hpa2-Nuc). Notably, overexpression of Hpa2 in breast carcinoma cells resulted in bigger tumors, whereas targeting Hpa2 to the cell nucleus attenuated tumor growth and tumor metastasis. RNAseq analysis was performed to reveal differentially expressed genes (DEG) in Hpa2-Nuc tumors vs. control. The analysis revealed, among others, decreased expression of genes associated with the hallmark of Kras, beta-catenin, and TNF-alpha (via NFkB) signaling. Our results imply that nuclear localization of Hpa2 prominently regulates gene transcription, resulting in attenuation of breast tumorigenesis. Thus, nuclear Hpa2 may be used as a predictive parameter in personalized medicine for breast cancer patients.
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Affiliation(s)
- Maram Hilwi
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | | | - Inna Naroditsky
- Departments of Pathology, Rambam Health Care Campus, Haifa, Israel
| | - Sari Feld
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Miriam Gross-Cohen
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Ilanit Boyango
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Soaad Soboh
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Olga Vornicova
- Department of Oncology, Ha'amek Medical Center, Afula, Israel
| | - Malik Farhoud
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Preeti Singh
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Gil Bar-Sela
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
- Department of Oncology, Ha'amek Medical Center, Afula, Israel
| | | | - Martin Götte
- Department of Gynecology and Obstetrics, Münster University Hospital, Muenster, Germany
| | - Andrew D Sharrocks
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Yaoyong Li
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Ralph D Sanderson
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Neta Ilan
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Israel Vlodavsky
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel.
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Lai B, Jiang H, Liao T, Gao Y, Zhou X. Bioinformatics and system biology analysis revealed the crosstalk between COVID-19 and osteoarthritis. Immun Inflamm Dis 2023; 11:e1123. [PMID: 38156385 PMCID: PMC10739374 DOI: 10.1002/iid3.1123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 11/12/2023] [Accepted: 12/05/2023] [Indexed: 12/30/2023] Open
Abstract
BACKGROUND The global coronavirus disease 2019 (COVID-19) outbreak has significantly impacted public health. Moreover, there has been an association between the incidence and severity of osteoarthritis (OA) and the onset of COVID-19. However, the optimal diagnosis and treatment strategies for patients with both diseases remain uncertain. Bioinformatics is a novel approach that may help find the common pathology between COVID-19 and OA. METHODS Differentially expressed genes (DEGs) were screened by R package "limma." Functional enrichment analyses were performed to find key biological functions. Protein-protein interaction (PPI) network was constructed by STRING database and then Cytoscape was used to select hub genes. External data sets and OA mouse model validated and identified the hub genes in both mRNA and protein levels. Related transcriptional factors (TF) and microRNAs (miRNAs) were predicted with miRTarBase and JASPR database. Candidate drugs were obtained from Drug Signatures database. The immune infiltration levels of COVID-19 and OA were evaluated by CIBERSORT and scRNA-seq. RESULTS A total of 74 common DEGs were identified between COVID-19 and OA. Receiver operating characteristic curves validated the effective diagnostic values (area under curve > 0.7) of four hub genes (matrix metalloproteinases 9, ATF3, CCL4, and RELA) in both the training and validation data sets of COVID-19 and OA. Quantitative polymerase chain reaction and Western Blot showed significantly higher hub gene expression in OA mice than in healthy controls. A total of 84 miRNAs and 28 TFs were identified to regulate the process of hub gene expression. The top 10 potential drugs were screened including "Simvastatin," "Hydrocortisone," and "Troglitazone" which have been proven by Food and Drug Administration. Correlated with hub gene expression, Macrophage M0 was highly expressed while Natural killer cells and Mast cells were low in both COVID-19 and OA. CONCLUSION Four hub genes, disease-related miRNAs, TFs, drugs, and immune infiltration help to understand the pathogenesis and perform further studies, providing a potential therapy target for COVID-19 and OA.
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Affiliation(s)
- Bowen Lai
- Department of OrthopedicsChangzheng Hospital, Second Military Medical UniversityShanghaiChina
| | - Heng Jiang
- Department of OrthopedicsChangzheng Hospital, Second Military Medical UniversityShanghaiChina
| | - Taotao Liao
- Department of OrthopedicsChangzheng Hospital, Second Military Medical UniversityShanghaiChina
| | - Yuan Gao
- Department of OrthopedicsChangzheng Hospital, Second Military Medical UniversityShanghaiChina
| | - Xuhui Zhou
- Department of OrthopedicsChangzheng Hospital, Second Military Medical UniversityShanghaiChina
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Kayal Y, Barash U, Naroditsky I, Ilan N, Vlodavsky I. Heparanase 2 (Hpa2)- a new player essential for pancreatic acinar cell differentiation. Cell Death Dis 2023; 14:465. [PMID: 37491420 PMCID: PMC10368643 DOI: 10.1038/s41419-023-05990-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/12/2023] [Accepted: 07/12/2023] [Indexed: 07/27/2023]
Abstract
Heparanase 2 (Hpa2, HPSE2) is a close homolog of heparanase. Hpa2, however, lacks intrinsic heparan sulfate (HS)-degrading activity, the hallmark of heparanase enzymatic activity. Mutations of HPSE2 were identified in patients diagnosed with urofacial syndrome (UFS), a rare genetic disorder that exhibits abnormal facial expression and bladder voiding dysfunction, leading to renal damage and eventually renal failure. In order to reveal the role of HPSE2 in tissue homeostasis, we established a conditional Hpa2-KO mouse. Interestingly, the lack of Hpa2 was associated with a marked decrease in the expression of key pancreatic transcription factors such as PTF1, GATA6, and Mist1. This was associated with a two-fold decrease in pancreas weight, increased pancreatic inflammation, and profound morphological alterations of the pancreas. These include massive accumulation of fat cells, possibly a result of acinar-to-adipocyte transdifferentiation (AAT), as well as acinar-to-ductal metaplasia (ADM), both considered to be pro-tumorigenic. Furthermore, exposing Hpa2-KO but not wild-type mice to a carcinogen (AOM) and pancreatic inflammation (cerulein) resulted in the formation of pancreatic intraepithelial neoplasia (PanIN), lesions that are considered to be precursors of invasive ductal adenocarcinoma of the pancreas (PDAC). These results strongly support the notion that Hpa2 functions as a tumor suppressor. Moreover, Hpa2 is shown here for the first time to play a critical role in the exocrine aspect of the pancreas.
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Affiliation(s)
- Yasmin Kayal
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Uri Barash
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Inna Naroditsky
- Department of Pathology, Rambam Health Care Campus, Haifa, Israel
| | - Neta Ilan
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Israel Vlodavsky
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel.
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Vlodavsky I, Kayal Y, Hilwi M, Soboh S, Sanderson RD, Ilan N. Heparanase-A single protein with multiple enzymatic and nonenzymatic functions. PROTEOGLYCAN RESEARCH 2023; 1:e6. [PMID: 37547889 PMCID: PMC10398610 DOI: 10.1002/pgr2.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/15/2023] [Accepted: 06/16/2023] [Indexed: 08/08/2023]
Abstract
Heparanase (Hpa1) is expressed by tumor cells and cells of the tumor microenvironment and functions extracellularly to remodel the extracellular matrix (ECM) and regulate the bioavailability of ECM-bound factors, augmenting, among other effects, gene transcription, autophagy, exosome formation, and heparan sulfate (HS) turnover. Much of the impact of heparanase on tumor progression is related to its function in mediating tumor-host crosstalk, priming the tumor microenvironment to better support tumor growth, metastasis, and chemoresistance. The enzyme appears to fulfill some normal functions associated, for example, with vesicular traffic, lysosomal-based secretion, autophagy, HS turnover, and gene transcription. It activates cells of the innate immune system, promotes the formation of exosomes and autophagosomes, and stimulates signal transduction pathways via enzymatic and nonenzymatic activities. These effects dynamically impact multiple regulatory pathways that together drive tumor growth, dissemination, and drug resistance as well as inflammatory responses. The emerging premise is that heparanase expressed by tumor cells, immune cells, endothelial cells, and other cells of the tumor microenvironment is a key regulator of the aggressive phenotype of cancer, an important contributor to the poor outcome of cancer patients and a valid target for therapy. So far, however, antiheparanase-based therapy has not been implemented in the clinic. Unlike heparanase, heparanase-2 (Hpa2), a close homolog of heparanase (Hpa1), does not undergo proteolytic processing and hence lacks intrinsic HS-degrading activity, the hallmark of heparanase. Hpa2 retains the capacity to bind heparin/HS and exhibits an even higher affinity towards HS than heparanase, thus competing for HS binding and inhibiting heparanase enzymatic activity. It appears that Hpa2 functions as a natural inhibitor of Hpa1 regulates the expression of selected genes that maintain tissue hemostasis and normal function, and plays a protective role against cancer and inflammation, together emphasizing the significance of maintaining a proper balance between Hpa1 and Hpa2.
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Affiliation(s)
- Israel Vlodavsky
- Technion Integrated Cancer Center, TechnionRappaport Faculty of MedicineHaifaIsrael
| | - Yasmin Kayal
- Technion Integrated Cancer Center, TechnionRappaport Faculty of MedicineHaifaIsrael
| | - Maram Hilwi
- Technion Integrated Cancer Center, TechnionRappaport Faculty of MedicineHaifaIsrael
| | - Soaad Soboh
- Technion Integrated Cancer Center, TechnionRappaport Faculty of MedicineHaifaIsrael
| | - Ralph D. Sanderson
- Department of PathologyUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Neta Ilan
- Technion Integrated Cancer Center, TechnionRappaport Faculty of MedicineHaifaIsrael
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Yang Y, Yuan F, Zhou H, Quan J, Liu C, Wang Y, Xiao F, Liu Q, Liu J, Zhang Y, Yu X. Potential roles of heparanase in cancer therapy: Current trends and future direction. J Cell Physiol 2023; 238:896-917. [PMID: 36924082 DOI: 10.1002/jcp.30995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/23/2023] [Accepted: 02/28/2023] [Indexed: 03/17/2023]
Abstract
Heparanase (HPSE; heparanase-1) is an endo-β-glucuronidase capable of degrading the carbohydrate moiety of heparan sulfate proteoglycans, thus modulating and facilitating the remodeling of the extracellular matrix and basement membrane. HPSE activity is strongly associated with major human pathological complications, including but not limited to tumor progress and angiogenesis. Several lines of literature have shown that overexpression of HPSE leads to enhanced tumor growth and metastatic transmission, as well as poor prognosis. Gene silencing of HPSE or treatment of tumor with compounds that block HPSE activity are shown to remarkably attenuate tumor progression. Therefore, targeting HPSE is considered as a potential therapeutical strategy for the treatment of cancer. Intriguingly, recent findings disclose that heparanase-2 (HPSE-2), a close homolog of HPSE but lacking enzymatic activity, can also regulate antitumor mechanisms. Given the pleiotropic roles of HPSE, further investigation is in demand to determine the precise mechanism of regulating action of HPSE in different cancer settings. In this review, we first summarize the current understanding of HPSE, such as its structure, subcellular localization, and tissue distribution. Furthermore, we systematically review the pro- and antitumorigenic roles and mechanisms of HPSE in cancer progress. In addition, we delineate HPSE inhibitors that have entered clinical trials and their therapeutic potential.
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Affiliation(s)
- Yiyuan Yang
- Key Laboratory of Model Animals and Stem Cell Biology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, China
| | - Fengyan Yuan
- Key Laboratory of Model Animals and Stem Cell Biology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, China
| | - Huiqin Zhou
- Key Laboratory of Model Animals and Stem Cell Biology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, China
| | - Jing Quan
- Key Laboratory of Model Animals and Stem Cell Biology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, China
| | - Chongyang Liu
- Key Laboratory of Model Animals and Stem Cell Biology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, China
| | - Yi Wang
- Key Laboratory of Model Animals and Stem Cell Biology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, China
| | - Fen Xiao
- Key Laboratory of Model Animals and Stem Cell Biology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, China
| | - Qiao Liu
- Key Laboratory of Model Animals and Stem Cell Biology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, China
| | - Jie Liu
- Key Laboratory of Model Animals and Stem Cell Biology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, China
| | - Yujing Zhang
- Key Laboratory of Model Animals and Stem Cell Biology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, China
| | - Xing Yu
- Key Laboratory of Model Animals and Stem Cell Biology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, China
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Ostrovsky O, Beider K, Magen H, Leiba M, Sanderson RD, Vlodavsky I, Nagler A. Effect of HPSE and HPSE2 SNPs on the Risk of Developing Primary Paraskeletal Multiple Myeloma. Cells 2023; 12:913. [PMID: 36980254 PMCID: PMC10047783 DOI: 10.3390/cells12060913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/09/2023] [Accepted: 03/13/2023] [Indexed: 03/18/2023] Open
Abstract
Multiple myeloma (MM) is a plasma cell malignancy that is accompanied by hypercalcemia, renal failure, anemia, and lytic bone lesions. Heparanase (HPSE) plays an important role in supporting and promoting myeloma progression, maintenance of plasma cell stemness, and resistance to therapy. Previous studies identified functional single nucleotide polymorphisms (SNPs) located in the HPSE gene. In the present study, 5 functional HPSE SNPs and 11 novel HPSE2 SNPs were examined. A very significant association between two enhancer (rs4693608 and rs4693084), and two insulator (rs4364254 and rs4426765) HPSE SNPs and primary paraskeletal disease (PS) was observed. SNP rs657442, located in intron 9 of the HPSE2 gene, revealed a significant protective association with primary paraskeletal disease and lytic bone lesions. The present study demonstrates a promoting (HPSE gene) and protective (HPSE2 gene) role of gene regulatory elements in the development of paraskeletal disease and bone morbidity. The effect of signal discrepancy between myeloma cells and normal cells of the tumor microenvironment is proposed as a mechanism for the involvement of heparanase in primary PS. We suggest that an increase in heparanase-2 expression can lead to effective suppression of heparanase activity in multiple myeloma accompanied by extramedullary and osteolytic bone disease.
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Affiliation(s)
- Olga Ostrovsky
- Department of Hematology and Bone Marrow Transplantation, Chaim Sheba Medical Center, Tel-Hashomer 5266202, Israel
| | - Katia Beider
- Department of Hematology and Bone Marrow Transplantation, Chaim Sheba Medical Center, Tel-Hashomer 5266202, Israel
| | - Hila Magen
- Department of Hematology and Bone Marrow Transplantation, Chaim Sheba Medical Center, Tel-Hashomer 5266202, Israel
| | - Merav Leiba
- Department of Hematology and Bone Marrow Transplantation, Chaim Sheba Medical Center, Tel-Hashomer 5266202, Israel
| | - Ralph D. Sanderson
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Israel Vlodavsky
- Technion Integrated Cancer Center (TICC), Rappaport Faculty of Medicine, Technion, Haifa 3525433, Israel
| | - Arnon Nagler
- Department of Hematology and Bone Marrow Transplantation, Chaim Sheba Medical Center, Tel-Hashomer 5266202, Israel
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Knani I, Yanku Y, Gross-Cohen M, Ilan N, Vlodavsky I. Heparanase 2 (Hpa2) attenuates the growth of human sarcoma. Matrix Biol 2022; 113:22-38. [PMID: 36122821 DOI: 10.1016/j.matbio.2022.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 08/25/2022] [Accepted: 09/14/2022] [Indexed: 11/18/2022]
Abstract
The pro-tumorigenic properties of heparanase are well documented and established. In contrast, the role of heparanase 2 (Hpa2), a close homolog of heparanase, in cancer is not entirely clear. In carcinomas, Hpa2 is thought to attenuate tumor growth, possibly by inhibiting heparanase enzymatic activity. Here, we examine the role of Hpa2 in sarcoma, a group of rare tumors of mesenchymal origin, accounting for approximately 1% of all malignant tumors. Consistently, we found that overexpression of Hpa2 attenuates tumor growth while Hpa2 gene silencing results in bigger tumors. Mechanistically, attenuation of tumor growth by Hpa2 was associated with increased tumor stress conditions, involving ER stress, hypoxia, and JNK phosphorylation, leading to increased apoptotic cell death. In addition, overexpression of Hpa2 induces the expression of the p53 family member, p63 which, in sarcoma, functions to attenuate tumor growth. Moreover, we show that Hpa2 profoundly reduces stem cell characteristics of the sarcoma cells (stemness), most evident by failure of Hpa2 cells to grow as spheroids typical of stem cells. Likewise, expression of CD44, a well-established stem cell marker, was prominently decreased in Hpa2 cells. CD44 is also a cell surface receptor for hyaluronic acid (HA), a nonsulfated glycosaminoglycan that is enriched in connective tissues. Reduced expression of CD44 by Hpa2 may thus represent impaired cross-talk between Hpa2 and the extracellular matrix. Clinically, we found that Hpa2 is expressed by leiomyosarcoma tumor biopsies. Interestingly, nuclear localization of Hpa2 was associated with low-stage tumors. This finding opens a new direction in Hpa2 research.
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Affiliation(s)
- Ibrahim Knani
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Yifat Yanku
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Miriam Gross-Cohen
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Neta Ilan
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Israel Vlodavsky
- Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel.
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