HDAC10 inhibition represses melanoma cell growth and BRAF inhibitor resistance via upregulating SPARC expression.

Secreted protein acidic and rich in cysteine (SPARC), a conserved secreted glycoprotein, plays crucial roles in regulating various biological processes. SPARC is highly expressed and has profound implications in several cancer types, including melanoma. Understanding the mechanisms that govern SPARC expression in cancers has the potential to lead to improved cancer diagnosis, prognosis, treatment strategies, and patient outcomes. Here, we demonstrate that histone deacetylase 10 (HDAC10) is a key regulator of SPARC expression in melanoma cells. Depletion or inhibition of HDAC10 upregulates SPARC expression, whereas overexpression of HDAC10 downregulates it. Mechanistically, HDAC10 coordinates with histone acetyltransferase p300 to modulate the state of acetylation of histone H3 at lysine 27 (H3K27ac) at SPARC regulatory elements and the recruitment of bromodomain-containing protein 4 (BRD4) to these regions, thereby fine-tuning SPARC transcription. HDAC10 depletion and resultant SPARC upregulation repress melanoma cell growth primarily by activating AMPK signaling and inducing autophagy. Moreover, SPARC upregulation due to HDAC10 depletion partly accounts for the resensitization of resistant cells to a BRAF inhibitor. Our work reveals the role of HDAC10 in gene regulation through indirect histone modification and suggests a potential therapeutic strategy for melanoma or other cancers by targeting HDAC10 and SPARC.

HDAC10 blockade upregulates SPARC expression thereby repressing melanoma cell growth and BRAF inhibitor resistance.

Secreted Protein Acidic and Rich in Cysteine (SPARC), a highly conserved secreted glycoprotein, is crucial for various bioprocesses. Here we demonstrate that histone deacetylase 10 (HDAC10) is a key regulator of SPARC expression. HDAC10 depletion or inhibition upregulates, while overexpression of HDAC10 downregulates, SPARC expression. Mechanistically, HDAC10 coordinates with histone acetyltransferase p300 to modulate the acetylation state of histone H3 lysine 27 (H3K27ac) at SPARC regulatory elements and the recruitment of bromodomain-containing protein 4 (BRD4) to these regions, thereby tuning SPARC transcription. HDAC10 depletion and resultant SPARC upregulation repress melanoma cell growth, primarily by induction of autophagy via activation of AMPK signaling. Moreover, SPARC upregulation due to HDAC10 depletion partly accounts for the resensitivity of resistant cells to a BRAF inhibitor. Our work reveals the role of HDAC10 in gene regulation through epigenetic modification and suggests a potential therapeutic strategy for melanoma or other cancers by targeting HDAC10 and SPARC. Highlights: HDAC10 is the primary HDAC member that tightly controls SPARC expression. HDAC10 coordinates with p300 in modulating the H3K27ac state at SPARC regulatory elements and the recruitment of BRD4 to these regions. HDAC10 depletion and resultant SPARC upregulation inhibit melanoma cell growth by inducing autophagy via activation of AMPK signaling.SPARC upregulation as a result of HDAC10 depletion resensitizes resistant cells to BRAF inhibitors.

HDAC8-mediated inhibition of EP300 drives a transcriptional state that increases melanoma brain metastasis.

Melanomas can adopt multiple transcriptional states. Little is known about the epigenetic drivers of these cell states, limiting our ability to regulate melanoma heterogeneity. Here, we identify stress-induced HDAC8 activity as driving melanoma brain metastasis development. Exposure of melanocytes and melanoma cells to multiple stresses increases HDAC8 activation leading to a neural crest-stem cell transcriptional state and an amoeboid, invasive phenotype that increases seeding to the brain. Using ATAC-Seq and ChIP-Seq we show that increased HDAC8 activity alters chromatin structure by increasing H3K27ac and enhancing accessibility at c-Jun binding sites. Functionally, HDAC8 deacetylates the histone acetyltransferase EP300, causing its enzymatic inactivation. This, in turn, increases binding of EP300 to Jun-transcriptional sites and decreases binding to MITF-transcriptional sites. Inhibition of EP300 increases melanoma cell invasion, resistance to stress and increases melanoma brain metastasis development. HDAC8 is identified as a mediator of transcriptional co-factor inactivation and chromatin accessibility that drives brain metastasis.

Trapoxin A Analogue as a Selective Nanomolar Inhibitor of HDAC11.

Histone deacetylases (HDACs) are enzymes that regulate many important biological pathways. There is a need for the development of isoform-selective HDAC inhibitors for further biological applications. Here, we report the development of trapoxin A analogues as potent and selective inhibitors of HDAC11, an enzyme that can efficiently remove long-chain fatty acyl groups from proteins. In particular, we show that one of the trapoxin A analogues, TD034, has nanomolar potency in enzymatic assays. We show that in cells, TD034 is active at low micromolar concentrations and inhibits the defatty acylation of SHMT2, a known HDAC11 substrate. The high potency and selectivity of TD034 would permit further development of HDAC11 inhibitors for biological and therapeutic applications.

Reversible lysine fatty acylation of an anchoring protein mediates adipocyte adrenergic signaling.

N-myristoylation on glycine is an irreversible modification that has long been recognized to govern protein localization and function. In contrast, the biological roles of lysine myristoylation remain ill-defined. We demonstrate that the cytoplasmic scaffolding protein, gravin-α/A kinase-anchoring protein 12, is myristoylated on two lysine residues embedded in its carboxyl-terminal protein kinase A (PKA) binding domain. Histone deacetylase 11 (HDAC11) docks to an adjacent region of gravin-α and demyristoylates these sites. In brown and white adipocytes, lysine myristoylation of gravin-α is required for signaling via ß2- and ß3-adrenergic receptors (ß-ARs), which are G protein-coupled receptors (GPCRs). Lysine myristoylation of gravin-α drives ß-ARs to lipid raft membrane microdomains, which results in PKA activation and downstream signaling that culminates in protective thermogenic gene expression. These findings define reversible lysine myristoylation as a mechanism for controlling GPCR signaling and highlight the potential of inhibiting HDAC11 to manipulate adipocyte phenotypes for therapeutic purposes.

EGFR phosphorylates HDAC1 to regulate its expression and anti-apoptotic function.

HDAC1 is the prototypical human histone deacetylase (HDAC) enzyme responsible for catalyzing the removal of acetyl group from lysine residues on many substrate proteins. By deacetylating histones and non-histone proteins, HDAC1 has a profound effect on the regulation of gene transcription and many processes related to cell growth and cell death, including cell cycle progression, DNA repair, and apoptosis. Early studies reveal that, like most eukaryotic proteins, the functions and activities of HDAC1 are regulated by post-translational modifications. For example, serine phosphorylation of HDAC1 by protein kinase CK2 promotes HDAC1 deacetylase enzymatic activity and alters its interactions with proteins in corepressor complexes. Here, we describe an alternative signaling pathway by which HDAC1 activities are regulated. Specifically, we discover that EGFR activity promotes the tyrosine phosphorylation of HDAC1, which is necessary for its protein stability. A key EGFR phosphorylation site on HDAC1, Tyr72, mediates HDAC1's anti-apoptotic function. Given that HDAC1 overexpression and EGFR activity are strongly related with tumor progression and cancer cell survival, HDAC1 tyrosine phosphorylation may present a possible target to manipulate HDAC1 protein levels in future potential cancer treatment strategies.

HDAC11 regulates expression of C/EBPß and immunosuppressive molecules in myeloid-derived suppressor cells.

Myeloid-derived suppressor cells (MDSCs) constitute a heterogeneous population of immature myeloid cells derived from bone marrow and negatively regulate both innate and adaptive immunity in the tumor microenvironment. Previously we have demonstrated that MDSCs lacking histone deacetylase 11 (HDAC11) displayed an increased suppressive activity against CD8+ T-cells. However, the mechanisms of HDAC11 that contribute to the suppressive function of MDSCs remain unclear. Here, we show that arginase activity and NO production is significantly higher in HDAC11 knockout MDSCs when compared with wild-type (WT) controls. In the absence of HDAC11, elevated arginase level and enzymatic activity were observed preferentially in the tumor-infiltrated granulocytic MDSCs, whereas iNOS expression and NO production were increased in the tumor-infiltrated monocytic MDSCs. Of note and for the first time, we demonstrated an association between the elevated expression of immunosuppressive molecules with up-regulation of the transcription factor C/EBPß in MDSCs lacking HDAC11. Interestingly, the highest expression of C/EBPß was observed among CD11b+ Gr-1+ MDSCs isolated from tumor-bearing mice. The additional demonstration that HDAC11 is recruited to the promoter region of C/EBPß in WT MDSCs suggests a novel molecular mechanism by which HDAC11 influence the expression of immunosuppressive molecules in MDSCs through regulation of C/EBPß gene expression.

Regulation of histone deacetylase activities and functions by phosphorylation and its physiological relevance.

Histone deacetylases (HDACs) are conserved enzymes that regulate many cellular processes by catalyzing the removal of acetyl groups from lysine residues on histones and non-histone proteins. As appropriate for proteins that occupy such an essential biological role, HDAC activities and functions are in turn highly regulated. Overwhelming evidence suggests that the dysregulation of HDACs plays a major role in many human diseases. The regulation of HDACs is achieved by multiple different mechanisms, including posttranslational modifications. One of the most common posttranslational modifications on HDACs is reversible phosphorylation. Many HDAC phosphorylations are context-dependent, occurring in specific tissues or as a consequence of certain stimuli. Additionally, whereas phosphorylation can regulate some HDACs in a non-specific manner, many HDAC phosphorylations result in specific consequences. Although some of these modifications support normal HDAC function, aberrations can contribute to disease development. Here we review and critically evaluate how reversible phosphorylation activates or deactivates HDACs and, thereby, regulates their many functions under various cellular and physiological contexts.

Lactate production by Staphylococcus aureus biofilm inhibits HDAC11 to reprogramme the host immune response during persistent infection.

Staphylococcus aureus is a leading cause of biofilm-associated prosthetic joint infection (PJI), resulting in considerable disability and prolonged treatment. It is known that host leukocyte IL-10 production is required for S. aureus biofilm persistence in PJI. An S. aureus bursa aurealis Tn library consisting of 1,952 non-essential genes was screened for mutants that failed to induce IL-10 in myeloid-derived suppressor cells (MDSCs), which identified a critical role for bacterial lactic acid biosynthesis. We generated an S. aureus ddh/ldh1/ldh2 triple Tn mutant that cannot produce D- or L-lactate. Co-culture of MDSCs or macrophages with ddh/ldh1/ldh2 mutant biofilm produced substantially less IL-10 compared with wild-type S. aureus, which was also observed in a mouse model of PJI and led to reduced biofilm burden. Using MDSCs recovered from the mouse PJI model and in vitro leukocyte-biofilm co-cultures, we show that bacterial-derived lactate inhibits histone deacetylase 11, causing unchecked HDAC6 activity and increased histone 3 acetylation at the Il-10 promoter, resulting in enhanced Il-10 transcription in MDSCs and macrophages. Finally, we show that synovial fluid of patients with PJI contains elevated amounts of D-lactate and IL-10 compared with control subjects, and bacterial lactate increases IL-10 production by human monocyte-derived macrophages.

HDAC10 Regulates Cancer Stem-Like Cell Properties in KRAS-Driven Lung Adenocarcinoma.

Activation of oncogenic KRAS is the most common driving event in lung adenocarcinoma development. Despite the existing rationale for targeting activated KRAS and its downstream effectors, the failure of clinical trials to date indicates that the mechanism of KRAS-driven malignancy remains poorly understood. Here we report that histone deacetylase 10 (HDAC10) might function as a putative tumor suppressor in mice carrying a spontaneously activated oncogenic Kras allele. Hdac10 deletion accelerated KRAS-driven early-onset lung adenocarcinomas, increased macrophage infiltration in the tumor microenvironment, and shortened survival time in mice. Highly tumorigenic and stem-like lung adenocarcinoma cells were increased in Hdac10-deleted tumors compared with Hdac10 wild-type tumors. HDAC10 regulated the stem-like properties of KRAS-expressing tumor cells by targeting SOX9. Expression of SOX9 was significantly increased in Hdac10-deleted tumor cells and depletion of SOX9 in Hdac10 knockout (KO) lung adenocarcinoma cells inhibited growth of tumorspheres. The genes associated with TGFß pathway were enriched in Hdac10 KO tumor cells, and activation of TGFß signaling contributed to SOX9 induction in Hdac10 KO lung adenocarcinoma cells. Overall, our study evaluates the functions and mechanisms of action of HDAC10 in lung carcinogenesis that will inform the rationale for targeting its related regulatory signaling as an anticancer strategy. SIGNIFICANCE: These findings linking HDAC10 and lung tumorigenesis identify potential novel strategies for targeting HDAC10 as a treatment for lung cancer.

Regulation of poly(a)-specific ribonuclease activity by reversible lysine acetylation.

Poly(A)-specific ribonuclease (PARN) is a 3'-exoribonuclease that plays an important role in regulating the stability and maturation of RNAs. Recently, PARN has been found to regulate the maturation of the human telomerase RNA component (hTR), a noncoding RNA required for telomere elongation. Specifically, PARN cleaves the 3'-end of immature, polyadenylated hTR to form the mature, nonpolyadenylated template. Despite PARN's critical role in mediating telomere maintenance, little is known about how PARN's function is regulated by post-translational modifications. In this study, using shRNA- and CRISPR/Cas9-mediated gene silencing and knockout approaches, along with 3'-exoribonuclease activity assays and additional biochemical methods, we examined whether PARN is post-translationally modified by acetylation and what effect acetylation has on PARN's activity. We found PARN is primarily acetylated by the acetyltransferase p300 at Lys-566 and deacetylated by sirtuin1 (SIRT1). We also revealed how acetylation of PARN can decrease its enzymatic activity both in vitro, using a synthetic RNA probe, and in vivo, by quantifying endogenous levels of adenylated hTR. Furthermore, we also found that SIRT1 can regulate levels of adenylated hTR through PARN. The findings of our study uncover a mechanism by which PARN acetylation and deacetylation regulate its enzymatic activity as well as levels of mature hTR. Thus, PARN's acetylation status may play a role in regulating telomere length.

Secretome profiling identifies neuron-derived neurotrophic factor as a tumor-suppressive factor in lung cancer.

Clinical and preclinical studies show tissue-specific differences in tumorigenesis. Tissue specificity is controlled by differential gene expression. We prioritized genes that encode secreted proteins according to their preferential expression in normal lungs to identify candidates associated with lung cancer. Indeed, most of the lung-enriched genes identified in our analysis have known or suspected roles in lung cancer. We focused on the gene encoding neuron-derived neurotrophic factor (NDNF), which had not yet been associated with lung cancer. We determined that NDNF was preferentially expressed in the normal adult lung and that its expression was decreased in human lung adenocarcinoma and a mouse model of this cancer. Higher expression of NDNF was associated with better clinical outcome of patients with lung adenocarcinoma. Purified NDNF inhibited proliferation of lung cancer cells, whereas silencing NDNF promoted tumor cell growth in culture and in xenograft models. We determined that NDNF is downregulated through DNA hypermethylation near CpG island shores in human lung adenocarcinoma. Furthermore, the lung cancer-related DNA hypermethylation sites corresponded to the methylation sites that occurred in tissues with low NDNF expression. Thus, by analyzing the tissue-specific secretome, we identified a tumor-suppressive factor, NDNF, which is associated with patient outcomes in lung adenocarcinoma.

HDAC8 affects MGMT levels in glioblastoma cell lines via interaction with the proteasome receptor ADRM1.

Temozolomide (TMZ) is an alkylating agent chemotherapy drug used as a first-line treatment for glioblastoma multiforme (GBM). O6-methyl-guanine DNA methyltransferase (MGMT) repairs DNA damage induced by TMZ; hence, elevated MGMT levels usually correlate with TMZ resistance. MGMT promoter methylation is a key regulatory mechanism for MGMT expression and is important in overcoming TMZ therapy resistance. To date, little is known about how MGMT expression is regulated beyond promoter methylation. In this work, we show an alternative mechanism by which MGMT levels are regulated independent of its promoter methylation status. We found that inhibition of the histone deacetylase HDAC8 by either HDAC8-specific inhibitor PCI34051 or HDAC8 shRNA decreases MGMT levels in GBM cell lines. Furthermore, the proteasome receptor ADRM1 participates in this MGMT regulation by interacting with HDAC8. Interestingly, this interaction is disrupted by TMZ exclusively in TMZ sensitive cells, suggesting that this MGMT regulatory pathway might be inactivated in TMZ resistant cells. Consequently, HDAC8 inhibition in GBM cell lines increases DNA damage and cell cycle arrest and, eventually, decreases cell viability, likely due to the decrease in MGMT protein levels.

Emerging roles of histone modifications and HDACs in RNA splicing.

Histone modifications and RNA splicing, two seemingly unrelated gene regulatory processes, greatly increase proteome diversity and profoundly influence normal as well as pathological eukaryotic cellular functions. Like many histone modifying enzymes, histone deacetylases (HDACs) play critical roles in governing cellular behaviors and are indispensable in numerous biological processes. While the association between RNA splicing and histone modifications is beginning to be recognized, a lack of knowledge exists regarding the role of HDACs in splicing. Recent studies however, reveal that HDACs interact with spliceosomal and ribonucleoprotein complexes, actively control the acetylation states of splicing-associated histone marks and splicing factors, and thereby unexpectedly could modulate splicing. Here, we review the role of histone/protein modifications and HDACs in RNA splicing and discuss the convergence of two parallel fields, which supports the argument that HDACs, and perhaps most histone modifying enzymes, are much more versatile and far more complicated than their initially proposed functions. Analogously, an HDAC-RNA splicing connection suggests that splicing is regulated by additional upstream factors and pathways yet to be defined or not fully characterized. Some human diseases share common underlying causes of aberrant HDACs and dysregulated RNA splicing and, thus, further support the potential link between HDACs and RNA splicing.

HDAC8 Regulates a Stress Response Pathway in Melanoma to Mediate Escape from BRAF Inhibitor Therapy.

Melanoma cells have the ability to switch to a dedifferentiated, invasive phenotype in response to multiple stimuli. Here, we show that exposure of melanomas to multiple stresses including BRAF-MEK inhibitor therapy, hypoxia, and UV irradiation leads to an increase in histone deacetylase 8 (HDAC8) activity and the adoption of a drug-resistant phenotype. Mass spectrometry-based phosphoproteomics implicated HDAC8 in the regulation of MAPK and AP-1 signaling. Introduction of HDAC8 into drug-naïve melanoma cells conveyed resistance both in vitro and in vivo. HDAC8-mediated BRAF inhibitor resistance was mediated via receptor tyrosine kinase activation, leading to MAPK signaling. Although HDACs function at the histone level, they also regulate nonhistone substrates, and introduction of HDAC8 decreased the acetylation of c-Jun, increasing its transcriptional activity and enriching for an AP-1 gene signature. Mutation of the putative c-Jun acetylation site at lysine 273 increased transcriptional activation of c-Jun in melanoma cells and conveyed resistance to BRAF inhibition. In vivo xenograft studies confirmed the key role of HDAC8 in therapeutic adaptation, with both nonselective and HDAC8-specific inhibitors enhancing the durability of BRAF inhibitor therapy. Our studies demonstrate that HDAC8-specific inhibitors limit the adaptation of melanoma cells to multiple stresses including BRAF-MEK inhibition. SIGNIFICANCE: This study provides evidence that HDAC8 drives transcriptional plasticity in melanoma cells in response to a range of stresses through direct deacetylation of c-Jun.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/79/11/2947/F1.large.jpg.

Chromatin regulation by Histone H4 acetylation at Lysine 16 during cell death and differentiation in the myeloid compartment.

Histone H4 acetylation at Lysine 16 (H4K16ac) is a key epigenetic mark involved in gene regulation, DNA repair and chromatin remodeling, and though it is known to be essential for embryonic development, its role during adult life is still poorly understood. Here we show that this lysine is massively hyperacetylated in peripheral neutrophils. Genome-wide mapping of H4K16ac in terminally differentiated blood cells, along with functional experiments, supported a role for this histone post-translational modification in the regulation of cell differentiation and apoptosis in the hematopoietic system. Furthermore, in neutrophils, H4K16ac was enriched at specific DNA repeats. These DNA regions presented an accessible chromatin conformation and were associated with the cleavage sites that generate the 50 kb DNA fragments during the first stages of programmed cell death. Our results thus suggest that H4K16ac plays a dual role in myeloid cells as it not only regulates differentiation and apoptosis, but it also exhibits a non-canonical structural role in poising chromatin for cleavage at an early stage of neutrophil cell death.

HDAC11 regulates type I interferon signaling through defatty-acylation of SHMT2.

The smallest histone deacetylase (HDAC) and the only class IV HDAC member, HDAC11, is reported to regulate immune activation and tumorigenesis, yet its biochemical function is largely unknown. Here we identify HDAC11 as an efficient lysine defatty-acylase that is >10,000-fold more efficient than its deacetylase activity. Through proteomics studies, we hypothesized and later biochemically validated SHMT2 as a defatty-acylation substrate of HDAC11. HDAC11-catalyzed defatty-acylation did not affect the enzymatic activity of SHMT2. Instead, it affects the ability of SHMT2 to regulate type I IFN receptor ubiquitination and cell surface level. Correspondingly, HDAC11 depletion increased type I IFN signaling in both cell culture and mice. This study not only demonstrates that HDAC11 has an activity that is much more efficient than the corresponding deacetylase activity, but also expands the physiological functions of HDAC11 and protein lysine fatty acylation, which opens up opportunities to develop HDAC11-specific inhibitors as therapeutics to modulate immune responses.

Sirtuin 6 Attenuates Kaposi's Sarcoma-Associated Herpesvirus Reactivation by Suppressing Ori-Lyt Activity and Expression of RTA.

Kaposi's sarcoma-associated herpesvirus (KSHV; also called human herpesvirus 8 [HHV-8]), upon being reactivated, causes serious diseases in immunocompromised individuals. Its reactivation, especially how the cellular regulating mechanisms play roles in KSHV gene expression and viral DNA replication, is not fully understood. In searching for the cellular factors that regulate KSHV gene expression, we found that several histone deacetylases (HDACs) and sirtuins (SIRTs), including HDACs 2, 7, 8, and 11 and SIRTs 4 and 6, repress KSHV ori-Lyt promoter activity. Interestingly, the nuclear protein SIRT6 presents the greatest inhibitory effect on ori-Lyt promoter activity. A more detailed investigation revealed that SIRT6 exerts repressive effects on multiple promoters of KSHV. As a consequence of inhibiting the KSHV promoters, SIRT6 not only represses viral protein production but also inhibits viral DNA replication, as investigated in a KSHV-containing cell line, SLK-iBAC-gfpK52. Depletion of the SIRT6 protein using small interfering RNA could not directly reactivate KSHV from SLK-iBAC-gfpK52 cells but made the reactivation of KSHV by use of a small amount of the reactivator (doxycycline) more effective and enhanced viral DNA replication in the KSHV infection system. We performed DNA chromatin immunoprecipitation (ChIP) assays for SIRT6 in the SLK-iBAC-gfpK52 cell line to determine whether SIRT6 interacts with the KSHV genome in order to exhibit regulatory effects. Our results suggest that SIRT6 interacts with KSHV ori-Lyt and ORF50 promoters. Furthermore, the SIRT6-KSHV DNA interaction is significantly negated by reactivation. Therefore, we identified a cellular regulator, SIRT6, that represses KSHV replication by interacting with KSHV DNA and inhibiting viral gene expression.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) is a pathogen causing cancer in the immune-deficient population. The reactivation of KSHV from latency is important for it to be carcinogenic. Our finding that SIRT6 has inhibitory effects on KSHV reactivation by interacting with the viral genome and suppressing viral gene expression is important because it might lead to a strategy of interfering with KSHV reactivation. Overexpression of SIRT6 repressed the activities of several KSHV promoters, leading to reduced gene expression and DNA replication by KSHV in a KSHV bacterial artificial chromosome-containing cell line. Depletion of SIRT6 favored reactivation of KSHV from SLK-iBACV-gfpK52 cells. More importantly, we reveal that SIRT6 interacts with KSHV DNA. Whether the interaction of SIRT6 with KSHV DNA occurs at a global level will be further studied in the future.

Histone Deacetylase SIRT1 Targets Plk2 to Regulate Centriole Duplication.

The protein deacetylase SIRT1 (Sirtuin 1) regulates many cellular processes, including cell-cycle progression, DNA damage response, and metabolism. Although the centrosome is a key regulator of cell-cycle progression and genome stability, little is known concerning SIRT1 controlled centrosome-associated events. Here we report that the centrosome protein Plk2 is acetylated and undergoes deacetylation by SIRT1. Acetylation protects Plk2 from ubiquitination, and SIRT1-mediated deacetylation promotes ubiquitin-dependent degradation of Plk2. SIRT1 controls centriole duplication by temporally modulating centrosomal Plk2 levels. AURKA phosphorylates SIRT1 and promotes the SIRT1-Plk2 interaction in mitosis. In early-mid G1, phosphorylated SIRT1 deacetylates and promotes Plk2 degradation. In late G1, SIRT1 is hypophosphorylated and its affinity to Plk2 is decreased, resulting in a rapid accumulation of centrosomal Plk2, which contributes to the timely initiation of centriole duplication. Collectively, our findings uncover a critical role of SIRT1 in centriole duplication and provide a mechanistic insight into SIRT1-mediated centrosome-associated functions.