1
|
Cuttler K, Bignoux MJ, Otgaar TC, Chigumba S, Ferreira E, Weiss SFT. LRP::FLAG Reduces Phosphorylated Tau Levels in Alzheimer's Disease Cell Culture Models. J Alzheimers Dis 2021; 76:753-768. [PMID: 32568204 DOI: 10.3233/jad-200244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) is characterized by amyloid-β (Aβ) plaque and neurofibrillary tangle formation, respectively. Neurofibrillary tangles form as a result of the intracellular accumulation of hyperphosphorylated tau. Telomerase activity and levels of the human reverse transcriptase (hTERT) subunit of telomerase are significantly decreased in AD. Recently, it has been demonstrated that the 37 kDa/67 kDa laminin receptor (LRP/LR) interacts with telomerase and is implicated in Aβ pathology. Since both LRP/LR and telomerase are known to play a role in the Aβ facet of AD, we hypothesized that they might also play a role in tauopathy. OBJECTIVE This study aimed to determine if LRP/LR has a relationship with tau and whether overexpression of LRP::FLAG has an effect on tauopathy-related proteins. METHODS We employed confocal microscopy and FRET to determine whether LRP/LR and tau co-localize and interact. LRP::FLAG overexpression in HEK-293 and SH-SY5Y cells as well as analysis of tauopathy-related proteins was assessed by western blotting. RESULTS We demonstrate that LRP/LR co-localizes with tau in the perinuclear cell compartment and confirmed a direct interaction between LRP/LR and tau in HEK-293 cells. Overexpression of LRP::FLAG in HEK-293 and SH-SY5Y cells decreased total and phosphorylated tau levels with a concomitant decrease in PrPc levels, a tauopathy-related protein. LRP::FLAG overexpression also resulted in increased hTERT levels. CONCLUSION This data suggest that LRP/LR extends its role in AD through a direct interaction with tau, and recommend LRP::FLAG as a possible alternative AD therapeutic via decreasing phosphorylated tau levels.
Collapse
Affiliation(s)
- Katelyn Cuttler
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa.,Present Address: Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, Republic of South Africa
| | - Monique J Bignoux
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Tyrone C Otgaar
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Stephanie Chigumba
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Eloise Ferreira
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Stefan F T Weiss
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa
| |
Collapse
|
2
|
Vania L, Morris G, Ferreira E, Weiss SFT. Knock-down of LRP/LR influences signalling pathways in late-stage colorectal carcinoma cells. BMC Cancer 2021; 21:392. [PMID: 33836696 PMCID: PMC8035741 DOI: 10.1186/s12885-021-08081-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 03/22/2021] [Indexed: 12/24/2022] Open
Abstract
Background The 37 kDa/67 kDa laminin receptor (LRP/LR) is involved in several tumourigenic-promoting processes including cellular viability maintenance and apoptotic evasion. Thus, the aim of this study was to assess the molecular mechanism of LRP/LR on apoptotic pathways in late stage (DLD-1) colorectal cancer cells upon siRNA-mediated down-regulation of LRP/LR. Methods siRNAs were used to down-regulate the expression of LRP/LR in DLD-1 cells which was assessed using western blotting and qPCR. To evaluate the mechanistic role of LRP/LR, proteomic analysis of pathways involved in proliferation and apoptosis were investigated. The data from the study was analysed using a one-way ANOVA, followed by a two-tailed student’s t-test with a confidence interval of 95%. Results Here we show that knock-down of LRP/LR led to significant changes in the proteome of DLD-1 cells, exposing new roles of the protein. Moreover, analysis showed that LRP/LR may alter components of the MAPK, p53-apoptotic and autophagic signalling pathways to aid colorectal cancer cells in continuous growth and survival. Knock-down of LRP/LR also resulted in significant decreases in telomerase activity and telomerase-related proteins in the DLD-1 cells. Conclusions These findings show that LRP/LR is critically implicated in apoptosis and cell viability maintenance and suggest that siRNA-mediated knock-down of LRP/LR may be a possible therapeutic strategy for the treatment of colorectal cancer. Supplementary Information The online version contains supplementary material available at 10.1186/s12885-021-08081-3.
Collapse
Affiliation(s)
- Leila Vania
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, Republic of South Africa
| | - Gavin Morris
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, Republic of South Africa
| | - Eloise Ferreira
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, Republic of South Africa
| | - Stefan F T Weiss
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, Republic of South Africa.
| |
Collapse
|
3
|
MicroRNA-587 Functions as a Tumor Suppressor in Hepatocellular Carcinoma by Targeting Ribosomal Protein SA. BIOMED RESEARCH INTERNATIONAL 2020; 2020:3280530. [PMID: 32964027 PMCID: PMC7492906 DOI: 10.1155/2020/3280530] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/01/2020] [Accepted: 07/29/2020] [Indexed: 12/14/2022]
Abstract
Background Hepatocellular carcinoma (HCC) is one of the most highly aggressive cancer worldwide with an extremely poor prognosis. Evidence has revealed that microRNA-587 (miR-587) is abnormally expressed in a series of cancers. However, its expressions and functions in HCC have not been clearly acknowledged. Methods We detected the expression level of miR-587 both in the Gene Expression Omnibus (GEO) database and 86 paired clinical HCC tissues together with paired adjacent normal tissues by quantitative real-time PCR (qRT-PCR). Afterwards, the transfected HCC cell line SMMC-7721 cells were collected for the cell proliferation assay, cell-cycle arrest, cell migration, and invasion assays to explore the roles of miR-587 in regulating cellular function. In addition, bioinformatics analysis, combined with qRT-PCR and dual-luciferase reporter assays, were performed to confirm whether ribosomal protein SA (RPSA) mRNA was the direct target gene of miR-587. Moreover, the Cancer Genome Atlas (TCGA) and GEO databases as well as 86 paired clinical HCC tissues were used to verify the negative regulation between miR-587 and RPSA. Results In the present study, both the GEO database (GSE36915 and GSE74618) analysis and qRT-PCR analysis of 86 paired clinical tissues showed that miR-587 was significantly downregulated in HCC tissues. The overexpression of miR-587 inhibited proliferation, cell cycle, migration, and invasion in SMMC-7721 cells. In addition, miR-587 directly interacted with the 3′-untranslated region (UTR) of RPSA. Moreover, miR-587 overexpression directly suppressed RPSA expression, and the two genes were inversely expressed in HCC based on the analyses in TCGA and GEO (GSE36376) databases and qPCR analysis of 86 paired clinical tissues. Conclusion Our results demonstrate that miR-587 is downexpressed in HCC and regulates the cellular function by targeting RPSA.
Collapse
|
4
|
Vania L, Morris G, Otgaar TC, Bignoux MJ, Bernert M, Burns J, Gabathuse A, Singh E, Ferreira E, Weiss SFT. Patented therapeutic approaches targeting LRP/LR for cancer treatment. Expert Opin Ther Pat 2019; 29:987-1009. [PMID: 31722579 DOI: 10.1080/13543776.2019.1693543] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Introduction: The ubiquitously expressed 37 kDa/67 kDa high-affinity laminin receptor (laminin receptor precursor/laminin receptor, LRP/LR) is a protein found to play several roles within cells. The receptor is located in the nucleus, cytosol and the cell surface. LRP/LR mediates cell proliferation, cell adhesion and cell differentiation. As a result, it is seen to enhance tumor angiogenesis as well as invasion and adhesion, key steps in the metastatic cascade of cancer. Recent findings have shown that LRP/LR is involved in the maintenance of cell viability through apoptotic evasion, allowing for tumor progression. Thus, several patented therapeutic approaches targeting the receptor for the prevention and treatment of cancer have emerged.Areas covered: The several roles that LRP/LR plays in cancer progression as well as an overview of the current therapeutic patented strategies targeting LRP/LR and cancer to date.Expert opinion: Small molecule inhibitors, monoclonal antibodies and small interfering RNAs might act used as powerful tools in preventing tumor angiogenesis and metastasis through the induction of apoptosis and telomere erosion in several cancers. This review offers an overview of the roles played by LRP/LR in cancer progression, while providing novel patented approaches targeting the receptor as potential therapeutic routes for the treatment of cancer as well as various other diseases.
Collapse
Affiliation(s)
- Leila Vania
- School of Molecular and Cell Biology, University of the Witwatersrand, Wits, Johannesburg, Republic of South Africa
| | - Gavin Morris
- School of Molecular and Cell Biology, University of the Witwatersrand, Wits, Johannesburg, Republic of South Africa
| | - Tyrone C Otgaar
- School of Molecular and Cell Biology, University of the Witwatersrand, Wits, Johannesburg, Republic of South Africa
| | - Monique J Bignoux
- School of Molecular and Cell Biology, University of the Witwatersrand, Wits, Johannesburg, Republic of South Africa
| | - Martin Bernert
- School of Molecular and Cell Biology, University of the Witwatersrand, Wits, Johannesburg, Republic of South Africa
| | - Jessica Burns
- School of Molecular and Cell Biology, University of the Witwatersrand, Wits, Johannesburg, Republic of South Africa
| | - Anne Gabathuse
- Wits Commercial Enterprise, The Commercial Development Hub, Johannesburg, Republic of South Africa
| | - Elvira Singh
- School of Public Health, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Eloise Ferreira
- School of Molecular and Cell Biology, University of the Witwatersrand, Wits, Johannesburg, Republic of South Africa
| | - Stefan F T Weiss
- School of Molecular and Cell Biology, University of the Witwatersrand, Wits, Johannesburg, Republic of South Africa
| |
Collapse
|
5
|
Bignoux MJ, Cuttler K, Otgaar TC, Ferreira E, Letsolo BT, Weiss SF. LRP::FLAG Rescues Cells from Amyloid-β-Mediated Cytotoxicity Through Increased TERT Levels and Telomerase Activity. J Alzheimers Dis 2019; 69:729-741. [DOI: 10.3233/jad-190075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Monique J. Bignoux
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa
| | - Katelyn Cuttler
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa
| | - Tyrone C. Otgaar
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa
| | - Eloise Ferreira
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa
| | - Boitelo T. Letsolo
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa
| | - Stefan F.T. Weiss
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa
| |
Collapse
|
6
|
Vania L, Rebelo TM, Ferreira E, Weiss SFT. Knock-down of LRP/LR promotes apoptosis in early and late stage colorectal carcinoma cells via caspase activation. BMC Cancer 2018; 18:602. [PMID: 29843646 PMCID: PMC5975593 DOI: 10.1186/s12885-018-4531-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 05/18/2018] [Indexed: 11/29/2022] Open
Abstract
Background Cancer remains one of the leading causes of death around the world, where incidence and mortality rates are at a constant increase. Tumourigenic cells are characteristically seen to over-express the 37 kDa/67 kDa laminin receptor (LRP/LR) compared to their normal cell counterparts. This receptor has numerous roles in tumourigenesis including metastasis, angiogenic enhancement, telomerase activation, cell viability and apoptotic evasion. This study aimed to expose the role of LRP/LR on the cellular viability of early (SW-480) and late (DLD-1) stage colorectal cancer cells. Methods siRNA were used to down-regulate the expression of LRP/LR in SW-480 and DLD-1 cells which was assessed using western blotting. Subsequently, cell survival was evaluated using the MTT cell survival assay and confocal microscopy. Thereafter, Annexin V-FITC/PI staining and caspase activity assays were used to investigate the mechanism underlying the cell death observed upon LRP/LR knockdown. The data was analysed using Student’s t-test with a confidence interval of 95%, with p-values of less than 0.05 seen as significant. Results Here we reveal that siRNA-mediated knock-down of LRP led to notable decreases in cell viability through increased levels of apoptosis, apparent by compromised membrane integrity and significantly high caspase-3 activity. Down-regulated LRP resulted in a significant increase in caspase-8 and -9 activity in both cell lines. Conclusions These findings show that the receptor is critically implicated in apoptosis and that LRP/LR down-regulation induces apoptosis in early and late stage colorectal cancer cells through both apoptotic pathways. Thus, this study suggests that siRNA-mediated knock-down of LRP could be a possible therapeutic strategy for the treatment of early and late stage colorectal carcinoma. Electronic supplementary material The online version of this article (10.1186/s12885-018-4531-2) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Leila Vania
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, Republic of South Africa
| | - Thalia M Rebelo
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, Republic of South Africa
| | - Eloise Ferreira
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, Republic of South Africa
| | - Stefan F T Weiss
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, Republic of South Africa.
| |
Collapse
|
7
|
Otgaar TC, Ferreira E, Malindisa S, Bernert M, Letsolo BT, Weiss SFT. 37 kDa LRP::FLAG enhances telomerase activity and reduces senescent markers in vitro. Oncotarget 2017; 8:86646-86656. [PMID: 29156824 PMCID: PMC5689714 DOI: 10.18632/oncotarget.21278] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 08/15/2017] [Indexed: 12/16/2022] Open
Abstract
One of the core regulators of cellular aging are telomeres, repetitive DNA sequences at the ends of chromosomes that are maintained by the ribonucleoprotein DNA polymerase complex, telomerase. Recently, we demonstrated that knockdown of the 37kDa/ 67kDa laminin receptor (LRP/LR), a protein that promotes cell viability in tumorigenic and normal cells, reduces telomerase activity. We therefore hypothesized that upregulating LRP/LR might increase telomerase activity and impede aging. Here we show that overexpression of LRP::FLAG resulted in significantly elevated hTERT levels, telomerase activity and telomere length, respectively, with concomitantly reduced levels of senescence markers. These data suggest a novel function of LRP/LR hampering the onset of senescence through elevating hTERT levels and telomerase activity, respectively. LRP::FLAG might therefore act as a potential novel anti-aging drug through the impediment of the cellular aging process.
Collapse
Affiliation(s)
- Tyrone C Otgaar
- School of Molecular and Cell Biology, University of the Witwatersrand, Wits 2050, Republic of South Africa
| | - Eloise Ferreira
- School of Molecular and Cell Biology, University of the Witwatersrand, Wits 2050, Republic of South Africa
| | - Sibusiso Malindisa
- School of Molecular and Cell Biology, University of the Witwatersrand, Wits 2050, Republic of South Africa.,Present Address: Department of Life and Consumer Sciences, University of South Africa, Florida 1710, Republic of South Africa
| | - Martin Bernert
- School of Molecular and Cell Biology, University of the Witwatersrand, Wits 2050, Republic of South Africa
| | - Boitelo T Letsolo
- School of Molecular and Cell Biology, University of the Witwatersrand, Wits 2050, Republic of South Africa
| | - Stefan F T Weiss
- School of Molecular and Cell Biology, University of the Witwatersrand, Wits 2050, Republic of South Africa
| |
Collapse
|
8
|
Chetty CJ, Ferreira E, Jovanovic K, Weiss SFT. Knockdown of LRP/LR induces apoptosis in pancreatic cancer and neuroblastoma cells through activation of caspases. Exp Cell Res 2017; 360:264-272. [PMID: 28899658 DOI: 10.1016/j.yexcr.2017.09.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/07/2017] [Accepted: 09/08/2017] [Indexed: 12/21/2022]
Abstract
The 37kDa/67kDa laminin receptor (LRP/LR) serves various physiological and pathological roles such as enhancing tumour-related processes including metastasis, angiogenesis, cellular viability and telomerase activation in cancerous cell lines. The present study investigates the effect of siRNA mediated downregulation of LRP/LR on pancreatic cancer (AsPC-1) and neuroblastoma (IMR-32) cells. MTT and BrdU assays revealed that siRNA mediated downregulation of LRP resulted in a significant reduction in cell viability and cell proliferation. In addition, knock-down of LRP resulted in phosphatidylserine externalization, diminished nuclear integrity and significantly enhanced caspase-3 activity, which is indicative of apoptosis. LRP downregulation resulted in a significant increase in caspase-8 activity in IMR-32 cells and enhanced caspase-8 and 9 activity in AsPC-1 cells. These data recommend siRNA mediated knock-down of LRP as a potential therapeutic avenue for the treatment of pancreatic cancer and neuroblastoma.
Collapse
Affiliation(s)
- Carryn J Chetty
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, Republic of South Africa
| | - Eloise Ferreira
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, Republic of South Africa
| | - Katarina Jovanovic
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, Republic of South Africa
| | - Stefan F T Weiss
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, Republic of South Africa.
| |
Collapse
|
9
|
Munien C, Rebelo TM, Ferreira E, Weiss SF. IgG1-iS18 impedes the adhesive and invasive potential of early and late stage malignant melanoma cells. Exp Cell Res 2017; 351:135-141. [DOI: 10.1016/j.yexcr.2017.01.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/19/2017] [Accepted: 01/21/2017] [Indexed: 01/24/2023]
|
10
|
Anti-LRP/LR-specific antibody IgG1-iS18 impedes adhesion and invasion of pancreatic cancer and neuroblastoma cells. BMC Cancer 2016; 16:917. [PMID: 27884119 PMCID: PMC5123428 DOI: 10.1186/s12885-016-2953-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 11/09/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cancer has become a global burden due to its high incidence and mortality rates, with an estimated 14.1 million cancer cases reported worldwide in 2012 particularly as a result of metastasis. Metastasis involves two crucial steps: adhesion and invasion, and the non-integrin receptor; the 37-kDa/67-kDa laminin receptor precursor/ high affinity laminin receptor (LRP/LR) has been shown to be overexpressed on the surface of tumorigenic cells, thus being implicated in the enhancement of these two crucial steps. The current study investigated the role of LRP/LR on the aggressiveness of pancreatic cancer (AsPC-1) and neuroblastoma (IMR-32) cells with respect to their adhesive and invasive potential. METHODS AsPC-1 and IMR-32 cells were utilized as the experimental cell lines for the study. Cell surface LRP/LR levels were visualised and quantified on the experimental and control (MCF-7) cell lines via confocal microscopy and flow cytometry, respectively. Total LRP/LR levels in the cell lines were assessed by Western blotting and the adhesive and invasive potential of the above-mentioned cell lines was determined before and after supplementation with the anti-LRP/LR specific antibody IgG1-iS18. Statistical significance of the data was confirmed via the use of the two-tailed student's t-test and Pearson's correlation coefficient. RESULTS Flow cytometry revealed that AsPC-1 and IMR-32 cells displayed significantly higher cell surface LRP/LR levels in comparison to the MCF-7 control cell line. However, Western blotting and subsequent densitometric analysis revealed that all three tumorigenic cell lines displayed no significant difference in total LRP/LR levels. The treatment of AsPC-1 and IMR-32 cells with IgG1-iS18 caused a significant reduction in the adhesive and invasive potential of the cells to laminin-1 and through the ECM-like Matrigel™, respectively. Pearson's correlation coefficients indicated a high correlation, thus suggesting a directly proportional relationship between cell surface LRP/LR levels and the adhesive and invasive potential of AsPC-1 and IMR-32 cells. CONCLUSION These findings suggest that through the interference of the LRP/LR-laminin-1 interaction, the anti-LRP/LR specific antibody IgG1-iS18 may act as an alternative therapeutic tool for the treatment of metastatic pancreatic cancer and neuroblastoma.
Collapse
|