Search

Acute myeloid leukemia (AML) is an aggressive hematological malignancy. Nearly 50% of patients who receive the most intensive treatment inevitably suffer disease relapse, likely resulting from the persistence of drug‑resistant leukemia stem cells (LSCs). AML cells especially LSCs are highly dependent on mitochondrial oxidative phosphorylation (OXPHOS) for survival, but the mechanism involved in OXPHOS hyperactivity is unclear and a noncytotoxic strategy to inhibit OXPHOS is lacking. Here, we demonstrate for the first time that ZDHHC21 palmitoyltransferase serves as a key regulator of OXPHOS hyperactivity in AML cells. The depletion/inhibition of ZDHHC21 effectively induced myeloid differentiation and weakened stemness potential by inhibiting OXPHOS in AML cells. Interestingly, FLT3-ITD mutated AML cells expressed significantly higher levels of ZDHHC21 and exhibited better sensitivity to ZDHHC21 inhibition. Mechanistically, ZDHHC21 specifically catalyzed the palmitoylation of mitochondrial kinase AK2 and further activated OXPHOS in leukemic blasts. Inhibition of ZDHHC21 arrested the in vivo growth of AML cells and extended the survival of mice inoculated with AML cell lines and PDX-AML blasts. Moreover, targeting ZDHHC21 to suppress OXPHOS markedly eradicated AML blasts and enhanced chemotherapy efficacy in relapsed/refractory leukemia. Together, these findings not only uncover a new biological function of palmitoyltransferase ZDHHC21 in regulating AML oxidative phosphorylation, but also indicate that ZDHHC21 inhibition is a promising therapeutic regimen for patients with AML, especially relapsed/refractory leukemia.

PDF file - 2686K, The effect of bortezomib (BTZ) and ATRA on RARα expression and NBT reduction ability in HL60-vector and HL60-shRNA-STAT1 cells.

table S3

M2 polarization of macrophages is essential for their function in immunologic tolerance, which might promote tumorigenesis. However, the molecular mechanism behind the polarization process is not fully understood. Given that several lines of evidence have suggested that long noncoding RNAs (lncRNAs) could be involved in regulating immune cell differentiation and function, the current study aimed to identify the lncRNAs that specifically modulate M2 macrophage polarization. By utilizing a series of cell-based M2 macrophage polarization models, a total of 25 lncRNAs with altered expression were documented based on lncRNA microarray-based profiling assays. Among them, lncRNA-MM2P was the only lncRNA upregulated during M2 polarization but downregulated in M1 macrophages. Knockdown of lncRNA-MM2P blocked cytokine-driven M2 polarization of macrophages and weakened the angiogenesis-promoting feature of M2 macrophages by reducing phosphorylation on STAT6. Moreover, manipulating lncRNA-MM2P in macrophages impaired macrophage-mediated promotion of tumorigenesis, tumor growth in vivo, and tumor angiogenesis. Collectively, our study identifies lncRNA-MM2P as a modulator required for macrophage M2 polarization and uncovers its role in macrophage-promoted tumorigenesis.

Supplementary Table S1

Supplementary figures and figure legends

PDF file - 186K, The effect of bortezomib (BTZ) and ATRA on PML-RARα expression in NB4 cells.

PDF file - 147K

PDF file - 1344K, The effect of bortezomib (BTZ) on NF-κB pathway activity in HL60 cells.

M2-polarized tumor-associated macrophages (TAM) play a critical role in cancer invasion and metastasis. Here, we report that M2 macrophages enhanced metastasis of K7M2 WT osteosarcoma cells to the lungs in mice, thus establishing M2 TAMs as a therapeutic target for blocking osteosarcoma metastasis. We found that all-trans retinoic acid (ATRA) inhibited osteosarcoma metastasis via inhibiting the M2 polarization of TAMs. ATRA suppressed IL13- or IL4-induced M2-type macrophages, and then inhibited migration of osteosarcoma cells as promoted by M2-type macrophages in vitro. ATRA reduced the number of pulmonary metastatic nodes of osteosarcoma and decreased expression of M2-type macrophages in metastatic nodes both in intravenous injection and orthotopic transplantation models. ATRA's effect was independent of conventional STAT3/6 or C/EBPβ signaling, which regulate M2-like polarization of macrophages. Quantitative genomic and functional analyses revealed that MMP12, a macrophage-secreted elastase, was elevated in IL13-skewed TAM polarization, whereas ATRA treatment downregulated IL13-induced secretion of MMP12. This downregulation correlates with the antimetastasis effect of ATRA. Our results show the role of TAM polarization in osteosarcoma metastasis, identify a therapeutic opportunity for antimetastasis treatment, and indicate ATRA treatment as an approach for preventing osteosarcoma metastasis via M2-type polarization intervention. Cancer Immunol Res; 5(7); 547–59. ©2017 AACR.

S1. Macrophages activate the immunological function. S2. The effect of ATRA on proliferation and M1 polarization of macrophages. S3. RM's effect on K7M2 WT cells and ATRA abrogates migration-promoting feature of M2 macrophages in K7M2 WT cells. S4. ATRA eliminates migration-promoting feature of M2 macrophages in KHOS/NP and U2OS cells. S5. ATRA didn't inhibit the activation of STAT3/6, C/EBPβ and MAPK induced by IL-13 and IL-4. S6. The production of MMP12 and MMP9 in RAW264.7 and K7M2 WT cells.

PDF file - 1900K, Bortezomib (BTZ) synergized with ATRA to inhibit AML cell proliferation.

All-trans-retinoic acid (ATRA) has held great promise for differentiation-based therapy but reportedly downregulates retinoic acid receptor-α (RARα) in a proteasome-dependent manner, which leads to decreased acute myeloid leukemia (AML) cell differentiation efficiency. Therefore, research strategies that seek to further sensitize cells to retinoids and extend the range of retinoid-affected myeloid malignancies beyond acute promyelocytic leukemia (APL) are key investigative avenues. Here, we show that bortezomib, the first proteasome inhibitor approved for newly diagnosed and relapsed multiple myeloma, exhibited strong synergism with ATRA to promote HL60 and NB4 AML cell differentiation. We observed that bortezomib sensitized AML cells to ATRA-induced morphologic, biochemical, and functional changes, indicative of myeloid differentiation without cell death. In addition, treatment of human leukemia HL60 xenografts with bortezomib and ATRA together did not increase bortezomib-induced progressive weight loss but resulted in significant tumor growth inhibition in addition to increased differentiation (P < 0.05). These enhanced differentiation effects were accompanied by RARα stabilization and STAT1 activation. Taken together, our study was the first to evaluate bortezomib and ATRA synergy in AML cell differentiation and to assess new opportunities for bortezomib and ATRA combination as a promising approach for future differentiation therapy. Mol Cancer Ther; 12(2); 195–206. ©2012 AACR.

Wound healing assay of KHOS/NP cells infected with lentivirus-WSB1, lentivirus-RhoGDI2, lentivirus-WSB1 plus lentivirus-RhoGDI2, or control lentivirus (pCCL).

Supp Figure 1. The treatment of CT-707 reduced the protein level of CTGF under hypoxia. Supp Figure 2. CT-707 elicited apoptotic cell death but not cell cycle arrest under hypoxia. Supp Figure 3. The protein level of HIF-1α under hypoxia was not influenced by YAP depletion by siRNA. Supp Figure 4. FAK inhibition was not required for the hypoxic activity of CT-707. Supp Figure 5. The semi-quantitative analyses using density measurements on the protein levels displayed in Figure 5. Supp Figure 6. The correlation of FAK, IGF-1R and YAP target genes expression with the overall survival days of liver cancer patients. Supp Figure 7. The in vivo activities of CT-707 on HepG2-, Bel-7402-xenograft and H22-allograft models. Supp Figure 8. PF-562271 treatment caused death of HepG2-xenografted nude mice but imposed less activity than CT-707.

Given that Yes-associated protein (YAP) signaling acts as a critical survival input for hypoxic cancer cells in hepatocellular carcinoma (HCC), disruption of YAP function and the maintenance of hypoxia is an attractive way to treat HCC. Utilizing a cell-based YAP-TEAD luciferase reporter assay and functional analyses, we identified CT-707, a China-FDA approved multi-kinase inhibitor under clinical trial with remarkable inhibitory activity against YAP function. CT-707 exhibited prominent cytotoxicity under hypoxia on HCC cells, which was attributable to the inhibition of YAP signaling. CT-707 arrested tumor growth in HepG2, Bel-7402, and HCC patient-derived xenografts. Mechanistically, the inhibitory activity of CT-707 on YAP signaling was due to the interruption of hypoxia-activated IGF1R. Overall, these findings not only identify CT-707 as a promising hypoxia-targeting agent against HCC, but they also unveil IGF1R as a new modulator specifically regulating hypoxia-activated YAP signaling.Significance: CT-707 may represent a novel clinical approach for patients with HCC suffering poor drug response due to intratumor hypoxia. Cancer Res; 78(14); 3995–4006. ©2018 AACR.

Table S1.The list of proteins with 3-fold change in WSB1 overexpression KHOS/NP cells using SILAC assay.

Materials and Methods for Supplemental Figures

Yes-associated protein (YAP) and its paralog, transcriptional coactivator with PDZ-binding motif (TAZ), play pivotal roles in promoting the progression of hepatocellular carcinoma. However, the regulatory mechanism underpinning aberrant activation of YAP/TAZ in hepatocellular carcinoma remains unclear. In this study, we globally profiled the contribution of deubiquitinating enzymes (DUB) to both transcriptional activity and protein abundance of YAP/TAZ in hepatocellular carcinoma models and identified ubiquitin-specific peptidase 10 (USP10) as a potent YAP/TAZ-activating DUB. Mechanistically, USP10 directly interacted with and stabilized YAP/TAZ by reverting their proteolytic ubiquitination. Depletion of USP10 enhanced polyubiquitination of YAP/TAZ, promoted their proteasomal degradation, and ultimately arrested the proliferation of hepatocellular carcinoma in vitro and in vivo. Expression levels of USP10 positively correlated with the abundance of YAP/TAZ in hepatocellular carcinoma patient samples as well as in N-nitrosodiethylamine (DEN)-induced liver cancer mice models. Collectively, this study establishes the causal link between USP10 and hyperactivated YAP/TAZ in hepatocellular carcinoma cells and provides a rationale for potential therapeutic interventions in the treatment of patients with hepatocellular carcinoma harboring a high level of YAP/TAZ.Significance:These findings identify USP10 as a DUB of YAP/TAZ and its role in hepatocellular carcinoma progression, which may serve as a potential therapeutic target for hepatocellular carcinoma treatment.

Supplementary Figures, legends and tables

Supplementary Materials and Methods and Figure Legends.

Supplemental Table 1. The primer sequences for qRT-PCR assay Supplemental Table 2. The targeting sequences for siRNA Supplemental Table 3. The list of compounds for YAP-TEADs luciferase screening

Intratumoral hypoxia occurs in many solid tumors, where it is associated with the development of metastatic character. However, the connections between these phenomena are not fully understood. In this study, we define an integrative role for the E3 ubiquitin ligase subunit WSB1. In primary osteosarcomas, increased levels of WSB1 correlated with pulmonary metastatic potential. RNAi-mediated attenuation of WSB1 or disruption of its E3 ligase activity potently suppressed tumor metastasis. Quantitative proteomic and functional analyses revealed that WSB1 ubiquitylates the Rho-binding protein RhoGDI2 and promotes its proteasomal degradation, thereby activating Rac1 to stimulate tumor cell motility and invasion. Our findings show how WSB1 regulates key steps of the metastatic cascade in hypoxia-driven osteosarcoma, and they highlight a candidate therapeutic target to potentially improve the survival of patients with metastatic disease. Cancer Res; 75(22); 4839–51. ©2015 AACR.

In most acute promyelocytic leukemia (APL) cells, promyelocytic leukemia (PML) fuses to retinoic acid receptor α (RARα) due to chromosomal translocation, thus generating PML/RARα oncoprotein, which is a relatively stable oncoprotein for degradation in APL. Elucidating the mechanism regulating the stability of PML/RARα may help to degrade PML/RARα and eradicate APL cells. Here, we describe a deubiquitinase (DUB)-involved regulatory mechanism for the maintenance of PML/RARα stability and develop a novel pharmacological approach to degrading PML/RARα by inhibiting DUB. We utilized a DUB siRNA library to identify the ovarian tumor protease (OTU) family member deubiquitinase YOD1 as a critical DUB of PML/RARα. Suppression of YOD1 promoted the degradation of PML/RARα, thus inhibiting APL cells and prolonging the survival time of APL cell-bearing mice. Subsequent phenotypic screening of small molecules allowed us to identify ubiquitin isopeptidase inhibitor I (G5) as the first YOD1 pharmacological inhibitor. As expected, G5 notably degraded PML/RARα protein and eradicated APL, particularly drug-resistant APL cells. Importantly, G5 also showed a strong killing effect on primary patient-derived APL blasts. Overall, our study not only reveals the DUB-involved regulatory mechanism on PML/RARα stability and validates YOD1 as a potential therapeutic target for APL, but also identifies G5 as a YOD1 inhibitor and a promising candidate for APL, particularly drug-resistant APL treatment.

The dysregulation of transcription factors is widely associated with tumorigenesis. As the most well-defined transcription factor in multiple types of cancer, c-Myc can transform cells by transactivating various downstream genes. Given that there is no effective way to directly inhibit c-Myc, c-Myc targeting strategies hold great potential for cancer therapy. In this study, we found that WSB1, which has a highly positive correlation with c-Myc in 10 cancer cell lines and clinical samples, is a direct target gene of c-Myc, and can positively regulate c-Myc expression, which forms a feedforward circuit promoting cancer development. RNA sequencing results from Bel-7402 cells confirmed that WSB1 promoted c-Myc expression through the β-catenin pathway. Mechanistically, WSB1 affected β-catenin destruction complex-PPP2CA assembly and E3 ubiquitin ligase adaptor β-TRCP recruitment, which inhibited the ubiquitination of β-catenin and transactivated c-Myc. Of interest, the effect of WSB1 on c-Myc was independent of its E3 ligase activity. Moreover, overexpressing WSB1 in the Bel-7402 xenograft model could further strengthen the tumor-driven effect of c-Myc overexpression. Thus, our findings revealed a novel mechanism involved in tumorigenesis in which the WSB1/c-Myc feedforward circuit played an essential role, highlighting a potential c-Myc intervention strategy in cancer treatment.

Acute promyelocytic leukemia (APL) is driven by the oncoprotein PML/RARα, which destroys the architecture of PML nuclear bodies (NBs). PML NBs are critical to tumor suppression, and their disruption mediated by PML/RARα accelerates APL pathogenesis. However, the mechanisms of PML NB disruption remain elusive. Here, we reveal that the failure of NB assembly in APL results from neddylation-induced aberrant phase separation of PML/RARα. Mechanistically, PML/RARα is neddylated in the RARα moiety, and this neddylation enhances its DNA-binding ability and further impedes the phase separation of the PML moiety, consequently disrupting PML NB construction. Accordingly, deneddylation of PML/RARα restores its phase separation process to reconstruct functional NBs and activates RARα signaling, thereby suppressing PML/RARα-driven leukemogenesis. Pharmacological inhibition of neddylation by MLN4924 eradicates APL cells both in vitro and in vivo. Our work elucidates the neddylation-destroyed phase separation mechanism for PML/RARα-driven NB disruption and highlights targeting neddylation for APL eradication.

The discovery of effective therapeutic treatments for cancer via cell differentiation instead of antiproliferation remains a great challenge. Cyclin-dependent kinase 2 (CDK2) inactivation, which overcomes the differentiation arrest of acute myeloid leukemia (AML) cells, may be a promising method for AML treatment. However, there is no available selective CDK2 inhibitor. More importantly, the inhibition of only the enzymatic function of CDK2 would be insufficient to promote notable AML differentiation. To further validate the role and druggability of CDK2 involved in AML differentiation, a suitable chemical tool is needed. Therefore, we developed first-in-class CDK2-targeted proteolysis-targeting chimeras (PROTACs), which promoted rapid and potent CDK2 degradation in different cell lines without comparable degradation of other targets, and induced remarkable differentiation of AML cell lines and primary patient cells. These data clearly demonstrated the practicality and importance of PROTACs as alternative tools for verifying CDK2 protein functions.

Cullin-RING ligases (CRLs) recognize and interact with substrates for ubiquitination and degradation, and can be targeted for disease treatment when the abnormal expression of substrates involves pathologic processes. Phosphorylation, either of substrates or receptors of CRLs, can alter their interaction. Phosphorylation-dependent ubiquitination and proteasome degradation influence various cellular processes and can contribute to the occurrence of various diseases, most often tumorigenesis. These processes have the potential to be used for tumor intervention through the regulation of the activities of related kinases, along with the regulation of the stability of specific oncoproteins and tumor suppressors. This review describes the mechanisms and biological functions of crosstalk between phosphorylation and ubiquitination, and most importantly its influence on tumorigenesis, to provide new directions and strategies for tumor therapy., Graphical abstract This review summarizes the crosstalk between phosphorylation and ubiquitination in different biological processes and diseases, mainly cancers, and highlights the therapeutic potential of the crosstalk in tumor treatments.Image 1

DJ-1 is a multifunctional protein associated with cancers and autosomal early-onset Parkinson disease. Besides the well-documented antioxidative stress activity, recent studies show that DJ-1 has deglycation enzymatic activity and anti-ferroptosis effect. It has been shown that DJ-1 forms the homodimerization, which dictates its antioxidative stress activity. In this study, we investigated the relationship between the dimeric structure of DJ-1 and its newly reported activities. In HEK293T cells with Flag-tagged and Myc-tagged DJ-1 overexpression, we performed deletion mutations and point mutations, narrowed down the most critical motif at the C terminus. We found that the deletion mutation of the last three amino acids at the C terminus of DJ-1 (DJ-1 ΔC3) disrupted its homodimerization with the hydrophobic L187 residue being of great importance for DJ-1 homodimerization. In addition, the ability in methylglyoxal (MGO) detoxification and deglycation was almost abolished in the mutation of DJ-1 ΔC3 and point mutant L187E compared with wild-type DJ-1 (DJ-1 WT). We also showed the suppression of erastin-triggered ferroptosis in DJ-1(−/−) mouse embryonic fibroblast cells was abolished by ΔC3 and L187E, but partially diminished by V51C. Thus, our results demonstrate that the C terminus of DJ-1 is crucial for its homodimerization, deglycation activity, and suppression of ferroptosis.

In recent years, phase separation has been increasingly reported to play a pivotal role in a wide range of biological processes. Due to the close relationships between cancer and disorders in intracellular physiological function, the identification of new mechanisms involved in intracellular regulation has been regarded as a new direction for cancer therapy. Introducing the concept of phase separation into complex descriptions of disease mechanisms may provide many different insights. Here, we review the recent findings on the phase separation of cancer‐related proteins, describing the possible relationships between phase separation and key proteins associated with cancer and indicate possible regulatory modalities, especially drug candidates for phase separation, which may provide more effective strategies for cancer therapy.

Yes-associated protein (YAP) and its paralog, transcriptional coactivator with PDZ-binding motif (TAZ), play pivotal roles in promoting the progression of hepatocellular carcinoma. However, the regulatory mechanism underpinning aberrant activation of YAP/TAZ in hepatocellular carcinoma remains unclear. In this study, we globally profiled the contribution of deubiquitinating enzymes (DUB) to both transcriptional activity and protein abundance of YAP/TAZ in hepatocellular carcinoma models and identified ubiquitin-specific peptidase 10 (USP10) as a potent YAP/TAZ-activating DUB. Mechanistically, USP10 directly interacted with and stabilized YAP/TAZ by reverting their proteolytic ubiquitination. Depletion of USP10 enhanced polyubiquitination of YAP/TAZ, promoted their proteasomal degradation, and ultimately arrested the proliferation of hepatocellular carcinoma in vitro and in vivo. Expression levels of USP10 positively correlated with the abundance of YAP/TAZ in hepatocellular carcinoma patient samples as well as in N-nitrosodiethylamine (DEN)-induced liver cancer mice models. Collectively, this study establishes the causal link between USP10 and hyperactivated YAP/TAZ in hepatocellular carcinoma cells and provides a rationale for potential therapeutic interventions in the treatment of patients with hepatocellular carcinoma harboring a high level of YAP/TAZ. Significance: These findings identify USP10 as a DUB of YAP/TAZ and its role in hepatocellular carcinoma progression, which may serve as a potential therapeutic target for hepatocellular carcinoma treatment.

The membrane protein claudin-3 (CLDN3) is critical for the formation and maintenance of tight junction and its high expression has been implicated in dictating malignant progression in various cancers. However, the post-translational modification of CLDN3 and its biological function remains poorly understood. Here, we report that CLDN3 is positively correlated with ovarian cancer progression both in vitro and in vivo. Of interest, CLDN3 undergoes S-palmitoylation on three juxtamembrane cysteine residues, which contribute to the accurate plasma membrane localization and protein stability of CLDN3. Moreover, the deprivation of S-palmitoylation in CLDN3 significantly abolishes its tumorigenic promotion effect in ovarian cancer cells. By utilizing the co-immunoprecipitation assay, we further identify ZDHHC12 as a CLDN3-targating palmitoyltransferase from 23 ZDHHC family proteins. Furthermore, the knockdown of ZDHHC12 also significantly inhibits CLDN3 accurate membrane localization, protein stability and ovarian cancer cells tumorigenesis. Thus, our work reveals S-palmitoylation as a novel regulatory mechanism that modulates CLDN3 function, which implies that targeting ZDHHC12-mediated CLDN3 S-palmitoylation might be a potential strategy for ovarian cancer therapy., Graphical abstract ZDHHC12-mediated S-palmitoylation promotes the cell membrane localization of CLDN3 and maintains its stability in ovarian cancer cells, contributing to the oncoprotein function of CLDN3. When ZDHHC12 was knocked down, CLDN3 was insufficiently S-palmitoylated leading to intracellular distribution and preference to degradation, which berried tumor growth.Image 1

Various lipids and lipid metabolites are bound to and modify the proteins in eukaryotic cells, which are known as ‘protein lipidation’. There are four major types of the protein lipidation, i.e. myristoylation, palmitoylation, prenylation, and glycosylphosphatidylinositol anchor. N-myristoylation refers to the attachment of 14-carbon fatty acid myristates to the N-terminal glycine of proteins by N-myristoyltransferases (NMT) and affects their physiology such as plasma targeting, subcellular tracking and localization, thereby influencing the function of proteins. With more novel pathogenic N-myristoylated proteins are identified, the N-myristoylation will attract great attentions in various human diseases including infectious diseases, parasitic diseases, and cancers. In this review, we summarize the current understanding of N-myristoylation in physiological processes and discuss the hitherto implication of crosstalk between N-myristoylation and other protein modification. Furthermore, we mention several well-studied NMT inhibitors mainly in infectious diseases and cancers and generalize the relation of NMT and cancer progression by browsing the clinic database. This review also aims to highlight the further investigation into the dynamic crosstalk of N-myristoylation in physiological processes as well as the potential application of protein N-myristoylation in translational medicine.

Hepatocellular carcinoma (HCC) has emerged as one of the most prevalent life‐threatening cancers, and the high mortality rate is largely due to the metastasis. The sustained activation of Smad4 and transforming growth factor‐β (TGF‐β) is closely associated with advanced HCC metastasis. However, the regulatory mechanism underlying the aberrant activation of Smad4 and TGF‐β pathway remains elusive. In this study, using a functional screen of USPs siRNA library, we identified ubiquitin‐specific proteases USP10 as a deubiquitinating enzyme (DUB) that sustains the protein level of Smad4 and activates TGF‐β signaling. Further analysis showed that USP10 directly interacts with Smad4 and stabilizes it through the cleavage of its proteolytic ubiquitination, thus promoting HCC metastasis. The suppression of USP10 by either shRNAs or catalytic inhibitor Spautin‐1 significantly inhibited the migration of HCC cells, whereas the reconstitution of Smad4 was able to efficiently rescue this defect. Overall, our study not only uncovers the regulatory effect of USP10 on the protein abundance of Smad4, but also indicates that USP10 could be regarded as a potential intervention target for the metastatic HCC in Smad4‐positive patients., Ubiquitin‐specific protease USP10 was shown to activate TGF‐β signaling and promote the metastasis of advanced HCC by deubiquitinating and stabilizing Smad4. Depletion of USP10 or inhibition of the USP10 catalytic activity by use of the small‐molecule inhibitor Spautin‐1 significantly repressed HCC metastasis, whereas reconstitution with Smad4 could efficiently rescue the metastatic phenotype.

Aldo-keto reductase family 1 member C1 (AKR1C1) promotes malignancy of Non-Small Cell Lung Cancer (NSCLC) by activating Signal Transducer and Activator of Transcription 3 (STAT3) pathway. However, how the pro-metastatic functions of AKR1C1 are switched on/off remains unknown. Methods: Immunoprecipitation and LC-MS/MS analyses were performed to identify the acetylation on AKR1C1 protein, and the functional analyses (in vitro and in vivo) were performed to depict the contribution of acetylation to the pro-metastatic effects of AKR1C1. Results: Here we report that acetylated AKR1C1 on two lysine residues K185 & K201 is critical to its pro-metastatic role. The acetylation modification has no impact on the canonical enzymatic activity of AKR1C1, while it is required for the interaction between AKR1C1 to STAT3, which triggers the downstream transduction events, ultimately mobilizing cells. Importantly, the deacetylase Sirtuin 2 (SIRT2) is capable of deacetylating AKR1C1, inhibiting the transactivation of STAT3 target genes, thus suppressing the migration of cells. Conclusion: Acetylation on Lysines 185 and 201 of AKR1C1 dictates its pro-metastatic potential both in vitro and in vivo, and the reverting of acetylation by Sirtuin 2 provides potential therapeutic targets for treatment against metastatic NSCLC patients with high AKR1C1 expression.

Stress granules (SGs) are primarily composed of mRNAs that stall at translation initiation and usually appear in the cytoplasm under unusual physiological or pathological conditions such as hypoxia, oxidative stress, and viral infection. Recent studies have indicated that several components of SGs participate in tumourigenesis and cancer metastasis through tumour‐associated signalling pathways as well as other mechanisms. Furthermore, some chemotherapy drugs have been reported to induce SGs. Thus, the roles of SGs in cancer treatment have attracted considerable interest. Importantly, disturbing the recruitment of SGs components or microtubule polymerization, as well as other strategies that can abolish SGs formation, is reported to inhibit tumour progression, suggesting that targeting SGs could be a promising strategy for cancer treatment. In this review, we summarize the relationship between SGs and cancer, as well as recent advances in targeting SGs, in the interest of providing new opportunities for cancer treatment.