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Parulekar A, Choksi A, Taye N, Totakura KVS, Firmal P, Kundu GC, Chattopadhyay S. SMAR1 suppresses the cancer stem cell population via hTERT repression in colorectal cancer cells. Int J Biochem Cell Biol 2021; 141:106085. [PMID: 34551340 DOI: 10.1016/j.biocel.2021.106085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 09/09/2021] [Accepted: 09/16/2021] [Indexed: 11/25/2022]
Abstract
One of the hallmarks of a cancer cell is the ability for indefinite proliferation leading to the immortalization of the cell. Activation of several signaling pathways leads to the immortalization of cancer cells via the reactivation of enzyme telomerase (hTERT). hTERT is active in germ cells, stem cells and also cancer cells. An earlier report from our lab suggests that SMAR1, a tumor suppressor protein, is significantly downregulated in the higher grades of colorectal cancers. Our study identifies SMAR1 as a transcriptional repressor of hTERT. We find that SMAR1 interacts with HDAC1/mSin3a co-repressor complex at the hTERT promoter and brings about HDAC1-mediated transcriptional repression of the promoter. Most solid tumors including colorectal cancer reactivate hTERT expression as it confers several advantages to the cancer cells like increased proliferation and angiogenesis. One of these non-canonical functions of hTERT is inducing the pool of cancer stem cell population. We find that in the CD133HighCD44High cancer stem cells population, SMAR1 expression is highly diminished leading to elevated hTERT expression. We also find that knockdown of SMAR1 promotes total CD133+CD44+ population and impart enhanced sphere-forming ability to the colorectal cancer cells. SMAR1 also inhibits invasion and metastasis in colorectal cancer cell lines via repression of hTERT. Our study provides evidence that downregulation of SMAR1 causes activation of hTERT leading to an increase in the cancer stem cell phenotype in colorectal cancer cells.
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Affiliation(s)
| | | | | | | | | | - Gopal C Kundu
- National Centre for Cell Science, Pune, India; Kalinga Institute of Industrial Technology, Bhubaneswar, India
| | - Samit Chattopadhyay
- National Centre for Cell Science, Pune, India; Birla Institute of Technology and Science, Goa, India.
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Choksi A, Parulekar A, Pant R, Shah VK, Nimma R, Firmal P, Singh S, Kundu GC, Shukla S, Chattopadhyay S. Tumor suppressor SMAR1 regulates PKM alternative splicing by HDAC6-mediated deacetylation of PTBP1. Cancer Metab 2021; 9:16. [PMID: 33863392 PMCID: PMC8052847 DOI: 10.1186/s40170-021-00252-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 03/30/2021] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Highly proliferating cancer cells exhibit the Warburg effect by regulation of PKM alternative splicing and promoting the expression of PKM2. Majority of the alternative splicing events are known to occur in the nuclear matrix where various MARBPs actively participate in the alternative splicing events. SMAR1, being a MARBP and an important tumor suppressor, is known to regulate the splicing of various cancer-associated genes. This study focuses on the regulation of PKM alternative splicing and inhibition of the Warburg effect by SMAR1. METHODS Immunohistochemistry was performed in breast cancer patient samples to establish the correlation between SMAR1 and PKM isoform expression. Further, expression of PKM isoforms upon modulation in SMAR1 expression in breast cancer cell lines was quantified by qRT-PCR and western blot. The acetylation status of PTBP1 was estimated by immunoprecipitation along with its enrichment on PKM pre-mRNA by CLIP in SMAR1 knockdown conditions. The role of SMAR1 in tumor metabolism and tumorigenesis was explored by in vitro enzymatic assays and functional assays upon SMAR1 knockdown. Besides, in vivo tumor formation by injecting adeno-SMAR1-transduced MDA-MB-231 cells in NOD/SCID mice was performed. RESULTS The expression profile of SMAR1 and PKM isoforms in breast cancer patients revealed that SMAR1 has an inverse correlation with PKM2 and a positive correlation with PKM1. Further quantitative PKM isoform expression upon modulation in SMAR1 expression also reflects that SMAR1 promotes the expression of PKM1 over tumorigenic isoform PKM2. SMAR1 deacetylates PTBP1 via recruitment of HDAC6 resulting in reduced enrichment of PTBP1 on PKM pre-mRNA. SMAR1 inhibits the Warburg effect, tumorigenic potential of cancer cells, and in vivo tumor generation in a PKM2-dependent manner. CONCLUSIONS SMAR1 regulates PKM alternative splicing by causing HDAC6-dependent deacetylation of PTBP1, resulting in reduced enrichment of PTBP1 on PKM pre-mRNA. Additionally, SMAR1 suppresses glucose utilization and lactate production via repression of PKM2 expression. This suggests that tumor suppressor SMAR1 inhibits tumor cell metabolism and tumorigenic properties of cancer cells via regulation of PKM alternative splicing.
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Affiliation(s)
| | | | - Richa Pant
- National Centre for Cell Science, Pune, 411007, India
| | | | | | | | - Smriti Singh
- Indian Institute of Science Education and Research, Bhopal, 462066, India
| | - Gopal C Kundu
- National Centre for Cell Science, Pune, 411007, India.,Kalinga Institute of Industrial Technology (KIIT), Bhubaneswar, 751024, India
| | - Sanjeev Shukla
- Indian Institute of Science Education and Research, Bhopal, 462066, India
| | - Samit Chattopadhyay
- National Centre for Cell Science, Pune, 411007, India. .,Birla Institute of Technology and Science, Pilani - K K Birla Goa Campus, Goa, 403726, India.
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Kao C, Segraves J, Parulekar A. Tacrolimus Time in Therapeutic Range and Level Variability are Not Associated with Acute Cellular Rejection in Lung Transplant Recipients. J Heart Lung Transplant 2020. [DOI: 10.1016/j.healun.2020.01.337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Parulekar A, Chattopadhayay S. PO-282 SMAR1 transcriptionally repress hTERT and alters the stem cell population in colorectal cancer cells. ESMO Open 2018. [DOI: 10.1136/esmoopen-2018-eacr25.313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Taye N, Alam A, Ghorai S, Chatterji DG, Parulekar A, Mogare D, Singh S, Sengupta P, Chatterjee S, Bhat MK, Santra MK, Salunkhe PB, Finston SK, Chattopadhyay S. SMAR1 inhibits Wnt/β-catenin signaling and prevents colorectal cancer progression. Oncotarget 2018; 9:21322-21336. [PMID: 29765542 PMCID: PMC5940383 DOI: 10.18632/oncotarget.25093] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 03/21/2018] [Indexed: 12/13/2022] Open
Abstract
Reduced expression of Scaffold/Matrix Attachment Region Binding Protein 1 (SMAR1) is associated with various cancers resulting in poor prognosis of the diseases. However, the precise underlying mechanism elucidating the loss of SMAR1 requires ongoing study. Here, we show that SMAR1 is highly downregulated during aberrant Wnt3a signaling due to proteasomal degradation and predicted poor prognosis of colorectal cancer. However, substitution mutation (Arginine and Lysine to Alanine) in the D-box elements of SMAR1 viz. "RCHL" and "RQRL" completely abrogated its proteasomal degradation despite Wnt3a activity. SMAR1 inhibited Wnt/β-catenin signaling by recruiting Histone deacetylase-5 to β-catenin promoter resulting in reduced cell migration and invasion. Consequently, reduced tumor sizes in in-vivo NOD-SCID mice were observed that strongly associated with suppression of β-catenin. However, loss of SMAR1 led to enriched H3K9 Acetylation in the β-catenin promoter that further increased Wnt/β-catenin signaling activities and enhanced colorectal cancer progression drastically. Using docking and isothermal titration calorimetric studies we show that small microbial peptides viz. AT-01C and AT-01D derived from Mycobacterium tuberculosis mask the D-box elements of SMAR1. These peptides stabilized SMAR1 expression that further inhibited metastatic SW480 colorectal cancer cell migration and invasion. Drastically reduced subcutaneous tumors were observed in in-vivo NOD-SCID mice upon administration of these peptides (25 mg/kg body weight) intraperitoneally. Taken together our structural studies, in-vitro and in-vivo results strongly suggest that the D-box elements of SMAR1 represent novel druggable targets, where the microbial peptides hold promise as novel colorectal cancer therapeutics.
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Affiliation(s)
- Nandaraj Taye
- National Centre for Cell Science, Pune 411 007, India
| | - Aftab Alam
- National Centre for Cell Science, Pune 411 007, India
| | | | | | | | - Devraj Mogare
- National Centre for Cell Science, Pune 411 007, India
| | | | - Pallabi Sengupta
- Department of Biophysics, Bose Institute, Kolkata 700 054, India
| | | | | | | | | | | | - Samit Chattopadhyay
- National Centre for Cell Science, Pune 411 007, India
- Indian Institute of Chemical Biology (CSIR), West Bengal, Kolkata 700 032, India
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Ramu V, Aute S, Taye N, Guha R, Walker MG, Mogare D, Parulekar A, Thomas JA, Chattopadhyay S, Das A. Photo-induced cytotoxicity and anti-metastatic activity of ruthenium(ii)–polypyridyl complexes functionalized with tyrosine or tryptophan. Dalton Trans 2017; 46:6634-6644. [DOI: 10.1039/c7dt00670e] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The synergestic effect of oxygen, light, and photosensitizer has found application in photodyanmic therapy (PDT).
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Affiliation(s)
- Vadde Ramu
- Organic Chemistry Division
- CSIR-National Chemical Laboratory
- Pune
- India
| | - Sunil Aute
- Organic Chemistry Division
- CSIR-National Chemical Laboratory
- Pune
- India
| | - Nandaraj Taye
- Chromatin and Disease Biology Laboratory
- National Centre for Cell Science
- Pune
- India
| | - Rweetuparna Guha
- Organic Chemistry Division
- CSIR-National Chemical Laboratory
- Pune
- India
| | | | - Devaraj Mogare
- Chromatin and Disease Biology Laboratory
- National Centre for Cell Science
- Pune
- India
| | - Apoorva Parulekar
- Chromatin and Disease Biology Laboratory
- National Centre for Cell Science
- Pune
- India
| | - Jim A. Thomas
- Department of Chemistry
- University of Sheffield
- Sheffield
- UK
| | - Samit Chattopadhyay
- Chromatin and Disease Biology Laboratory
- National Centre for Cell Science
- Pune
- India
- Indian Institute of Chemical Biology
| | - Amitava Das
- Organic Chemistry Division
- CSIR-National Chemical Laboratory
- Pune
- India
- CSIR-Central Salt and marine Chemicals Research Institute
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Hoang V, Li G, Dronovalli G, Capuano N, Kao C, Parulekar A. Pectoralis Muscle Area Change Following Lung Transplantation Is Related to Underlying Disease. J Heart Lung Transplant 2016. [DOI: 10.1016/j.healun.2016.01.083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Akkanti B, Kolodziejski P, Rizvi Z, Kesavan R, Parulekar A, Loebe M, La Francesca S, Scheinin S, Nguyen J, Bruckner B, Noon G, Seethamraju H. 356 H1N1 Influenza in Lung Transplant Patients: A Follow Up after One Year. J Heart Lung Transplant 2011. [DOI: 10.1016/j.healun.2011.01.364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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