1
|
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.
Collapse
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.
| |
Collapse
|
2
|
Pant R, Alam A, Choksi A, Shah VK, Firmal P, Chattopadhyay S. Chromatin remodeling protein SMAR1 regulates adipogenesis by modulating the expression of PPARγ. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:159045. [PMID: 34450266 DOI: 10.1016/j.bbalip.2021.159045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 08/15/2021] [Accepted: 08/21/2021] [Indexed: 11/17/2022]
Abstract
Adipogenesis is described as the process of conversion of pre-adipocytes into differentiated lipid-laden adipocytes. Adipogenesis is known to be regulated by a myriad of transcription factors and co-regulators. However, there is a dearth of information regarding the mechanisms that regulate these transcription factors and hence control adipogenesis. PPARγ is the master transcriptional regulator of adipogenesis and its expression is essential for adipocyte differentiation. Herein, we identified that scaffold/matrix attachment region-binding protein 1 (SMAR1) negatively regulates adipogenesis. We observed that SMAR1 gets downregulated during adipocyte differentiation and knockdown of SMAR1 promotes lipid accumulation and adipocyte differentiation. Mechanistically, we have shown that SMAR1 suppresses PPARγ through recruitment of the HDAC1/mSin3a repressor complex to the PPARγ promoter. We further identified cell division cycle 20 (cdc20) mediated proteasomal degradation of SMAR1 during adipogenesis. Moreover, knockdown of cdc20 resulted in stabilization of SMAR1 and a reduction in adipocyte differentiation. Taken together, our observations suggest that SMAR1 functions as a negative regulator of adipogenesis by inhibiting PPARγ expression in differentiating adipocytes.
Collapse
Affiliation(s)
- Richa Pant
- National Centre for Cell Science, S P Pune University Campus, Ganeshkhind, Pune 411007, India.
| | - Aftab Alam
- National Centre for Cell Science, S P Pune University Campus, Ganeshkhind, Pune 411007, India; Roswell Park Comprehensive Cancer Center, Buffalo, NY 14203, United States of America
| | - Arpankumar Choksi
- National Centre for Cell Science, S P Pune University Campus, Ganeshkhind, Pune 411007, India
| | - Vibhuti Kumar Shah
- National Centre for Cell Science, S P Pune University Campus, Ganeshkhind, Pune 411007, India
| | - Priyanka Firmal
- National Centre for Cell Science, S P Pune University Campus, Ganeshkhind, Pune 411007, India
| | - Samit Chattopadhyay
- National Centre for Cell Science, S P Pune University Campus, Ganeshkhind, Pune 411007, India; Department of Biological Sciences, BITS Pilani, K. K. Birla Goa Campus, NH 17B, Zuarinagar, Goa 403726, India; Indian Institute of Chemical Biology; 4, Raja S C Mullick Road, Jadavpur, Kolkata 700032, India.
| |
Collapse
|
3
|
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.
Collapse
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.
| |
Collapse
|
4
|
Choksi A, Tsymbalyuk S, Tolaymat B, Li G, Gandhi D, Miller T, Jindal G, Chao C. Abstract No. 463 First Independent review of the vascade vascular closure device: the only device marketed as “proven” safer than manual compression. J Vasc Interv Radiol 2019. [DOI: 10.1016/j.jvir.2018.12.544] [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: 11/25/2022] Open
|
5
|
Tolaymat B, Choksi A, Tsymbalyuk S, Li G, Ng V, Chao C. Abstract No. 553 Preoperative embolization of bone cancers: tumor types, location, estimated blood loss, and blood transfusion requirements. J Vasc Interv Radiol 2019. [DOI: 10.1016/j.jvir.2018.12.634] [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: 10/27/2022] Open
|
6
|
Khandelwal P, Alam A, Choksi A, Chattopadhyay S, Poddar P. Retention of Anticancer Activity of Curcumin after Conjugation with Fluorescent Gold Quantum Clusters: An in Vitro and in Vivo Xenograft Study. ACS Omega 2018; 3:4776-4785. [PMID: 30023902 PMCID: PMC6045371 DOI: 10.1021/acsomega.8b00113] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/23/2018] [Indexed: 05/05/2023]
Abstract
Gold nanoparticles (Au NPs) have been thoroughly investigated for anti-cancer therapy. However, their undesired high gold content remains a problem when injected into the body for drug delivery applications. In this report, we made an effort to conjugate the curcumin molecules on the surface of gold quantum clusters (Au QCs) by a novel in situ synthesis method which provides an alternative route to not only reduce the metallic content but also increase the water solubility of curcumin and the loading efficiency. Here, curcumin itself acts as a reducing and capping agent for the synthesis of Au QCs. The UV-vis absorption, fluorescence, transmission electron microscopy, and electrospray ionization mass spectrometry results confirmed the synthesis of fluorescent Au QCs. Curcumin-conjugated Au NPs (C-Au NPs) and glutathione (GSH)-conjugated Au QCs (GSH-Au QCs) were also synthesized to visualize the effect of particle size and the capping agent, respectively, on the cytotoxicity to normal and cancer cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that the curcumin-conjugated Au QCs (C-Au QCs) were less cytotoxic to normal cells while almost the same cytotoxic to cancer cells in comparison to curcumin itself, which indicates that curcumin preserves its anticancer property even after binding to the Au QCs. However, C-Au NPs and GSH-Au QCs did not show any cytotoxicity against the normal and cancer cells at the concentration used. The western blot assay indicated that C-Au QCs promote apoptosis in cancer cells. Further, the in vivo study on severe combined immunodeficiency mice showed that C-Au QCs also inhibited the tumor growth efficiently without showing significant toxicity to internal organs.
Collapse
Affiliation(s)
- Puneet Khandelwal
- Physical
& Materials Chemistry Division, CSIR-National
Chemical Laboratory, Pune 411008, India
| | - Aftab Alam
- National
Center for Cell Science, Ganeshkhind, Pune 411 007, India
| | | | - Samit Chattopadhyay
- CSIR-Indian
Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata 700 032, India
| | - Pankaj Poddar
- Physical
& Materials Chemistry Division, CSIR-National
Chemical Laboratory, Pune 411008, India
| |
Collapse
|
7
|
Choksi A, Sarojini KVL, Vadnal P, Dias C, Suresh PK, Khandare J. Comparative anti-inflammatory activity of poly(amidoamine) (PAMAM) dendrimer-dexamethasone conjugates with dexamethasone-liposomes. Int J Pharm 2013; 449:28-36. [PMID: 23583708 DOI: 10.1016/j.ijpharm.2013.03.056] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 03/27/2013] [Accepted: 03/28/2013] [Indexed: 12/18/2022]
Abstract
Lipophilicity vs hydrophicility physicochemical traits are extremely important variables that are active considerations for optimizing drug delivery systems. The comparative anti-inflammatory delivery potential of dexamethasone (dex) in an encapsulation-based (liposome-lipophilic) and poly (amidoamine) (PAMAM) dendrimer prodrug conjugation-based delivery systems (hydrophilic) was performed in this work. Dendrimer prodrug conjugates were characterized by (1)H NMR. The drug encapsulation efficiency for drug in liposomes was observed to be 14.02% and this was correlated with a dose-dependent tumor necrosis factor (TNF)-α inhibition (39-57% inhibition). The biological evaluation of nanocarriers for drug was demonstrated in a standard, conventionally used in vitro cell-based system for TNF-α inhibition. This served as a comparative tool to demonstrate a quantitatively higher TNF-α inhibition (67-71.48%) produced by the dendrimer-dex drug conjugate. The structure activity relationship (dose-for-dose) was inferred by relatively lesser inhibition of TNF-α by variants of PAMAM G4 (NH2) dendrimer-dex conjugates and was compared with liposomes carrying dex. In vitro results suggest that the prodrug conjugates of PAMAM dendrimer deliver dex to be more efficient in comparison with liposome-based dex in terms of higher TNF-α inhibition. This study has implications in designing efficient prodrug nanocarrier systems for delivering dex.
Collapse
Affiliation(s)
- Arpankumar Choksi
- School of Biosciences & Technology, VIT University, Vellore, Vellore Dt., 632014, India
| | | | | | | | | | | |
Collapse
|
8
|
Baijal R, Agal S, Kumar R, Kulshrestha PP, Amrapurkar DN, Choksi A, Desai HG. Hepatic artery aneurysm presenting as pain and mass in the epigastrium. J Assoc Physicians India 1998; 46:823. [PMID: 11229258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Affiliation(s)
- R Baijal
- Department of Gastroenterology, Jagjivan Ram Hospital, Western Railway, Mumbai Central, Mumbai
| | | | | | | | | | | | | |
Collapse
|