The relationship between weight-adjusted-waist index and diabetic kidney disease in patients with type 2 diabetes mellitus.

Purpose: Obesity, particularly abdominal obesity, is seen as a risk factor for diabetic complications. The weight-adjusted-waist index (WWI) is a recently developed index for measuring adiposity. Our goal was to uncover the potential correlation between the WWI index and diabetic kidney disease (DKD) risk. Methods: This cross-sectional study included adults with type 2 diabetes mellitus (T2DM) who participated in the NHANES database (2007-2018). The WWI index was calculated as waist circumference (WC, cm) divided by the square root of weight (kg). DKD was diagnosed based on impaired estimated glomerular filtration rate (eGFR<60 mL/min/1.73m2), albuminuria (urinary albumin to urinary creatinine ratio>30 mg/g), or both in T2DM patients. The independent relationship between WWI index and DKD risk was evaluated. Results: A total of 5,028 participants with T2DM were included, with an average WWI index of 11.61 ± 0.02. As the quartile range of the WWI index increased, the prevalence of DKD gradually increased (26.76% vs. 32.63% vs. 39.06% vs. 42.96%, P<0.001). After adjusting for various confounding factors, the WWI index was independently associated with DKD risk (OR=1.32, 95%CI:1.12-1.56, P<0.001). The area under the ROC curve (AUC) of the WWI index was higher than that of body mass index (BMI, kg/m2) and WC. Subgroup analysis suggested that the relationship between the WWI index and DKD risk was of greater concern in patients over 60 years old and those with cardiovascular disease. Conclusions: Our findings suggest that higher WWI levels are linked to DKD in T2DM patients. The WWI index could be a cost-effective and simple way to detect DKD, but further prospective studies are needed to confirm this.

The palmitoyltransferase ZDHHC21 regulates oxidative phosphorylation to induce differentiation block and stemness in AML.

Acute myeloid leukemia (AML) is an aggressive hematological malignancy. Nearly 50% of patients who receive the most intensive treatment inevitably experience 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. To our knowledge, this study is the first to demonstrate 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, FMS-like tyrosine kinase-3 internal tandem duplication (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 adenylate kinase 2 (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 patient derived xenograft 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 OXPHOS but also indicate that ZDHHC21 inhibition is a promising therapeutic regimen for patients with AML, especially relapsed/refractory leukemia.

Driving the degradation of oncofusion proteins for targeted cancer therapy.

Oncofusion proteins drive the development of about 16.5% of human cancers, functioning as the unique pathogenic factor in some cancers. The targeting of oncofusion proteins is an attractive strategy to treat malignant tumors. Recently, triggering the degradation of oncofusion proteins has been shown to hold great promise as a therapeutic strategy. Here, we review the recent findings on the mechanisms that maintain the high stability of oncofusion proteins. Then, we summarize strategies to target the degradation of oncofusion proteins through the ubiquitin-proteasome pathway, the autophagy-lysosomal pathway, and the caspase-dependent pathway. By examining oncofusion protein degradation in cancer, we not only gain better insight into the carcinogenic mechanisms that involve oncofusion proteins, but also raise the possibility of treating oncofusion-driven cancer.

Arctigenin impairs UBC12 enzyme activity and cullin neddylation to attenuate cancer cells.

Neddylation is a type of posttranslational protein modification that has been observed to be overactivated in various cancers. UBC12 is one of two key E2 enzymes in the neddylation pathway. Reports indicate that UBC12 deficiency may suppress lung cancer cells, such that UBC12 could play an important role in tumor progression. However, systematic studies regarding the expression profile of UBC12 in cancers and its relationship to cancer prognosis are lacking. In this study, we comprehensively analyzed UBC12 expression in diverse cancer types and found that UBC12 is markedly overexpressed in most cancers (17/21), a symptom that negatively correlates with the survival rates of cancer patients, including gastric cancer. These results demonstrate the suitability of UBC12 as a potential target for cancer treatment. Currently, no effective inhibitor targeting UBC12 has been discovered. We screened a natural product library and found, for the first time, that arctigenin has been shown to significantly inhibit UBC12 enzyme activity and cullin neddylation. The inhibition of UBC12 enzyme activity was newly found to contribute to the effects of arctigenin on suppressing the malignant phenotypes of cancer cells. Furthermore, we performed proteomics analysis and found that arctigenin intervened with cullin downstream signaling pathways and substrates, such as the tumor suppressor PDCD4. In summary, these results demonstrate the importance of UBC12 as a potential therapeutic target for cancer treatment, and, for the first time, the suitability of arctigenin as a potential compound targeting UBC12 enzyme activity. Thus, these findings provide a new strategy for inhibiting neddylation-overactivated cancers.

Blockade of deubiquitinase YOD1 degrades oncogenic PML/RARα and eradicates acute promyelocytic leukemia cells.

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.

Deneddylation of PML/RARα reconstructs functional PML nuclear bodies via orchestrating phase separation to eradicate APL.

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.

Advances in targeted therapy for osteosarcoma based on molecular classification.

Osteosarcoma, a highly malignant tumor, is characterized by widespread and recurrent chromosomal and genetic abnormalities. In recent years, a number of elaborated sequencing analyses have made it possible to cluster the osteosarcoma based on the identification of candidate driver genes and develop targeted therapy. Here, we reviewed recent next-generation genome sequencing studies and advances in targeted therapies for osteosarcoma based on molecular classification. First, we stratified osteosarcomas into ten molecular subtypes based on genetic changes. And we analyzed potential targeted therapies for osteosarcoma based on the identified molecular subtypes. Finally, the development of targeted therapies for osteosarcoma investigated in clinical trials were further summarized and discussed. Therefore, we indicated the importance of molecular classification on the targeted therapy for osteosarcoma. And the stratification of patients based on the genetic characteristics of osteosarcoma will help to obtain a better therapeutic response to targeted therapies, bringing us closer to the era of personalized medicine.

Targeting Cul3-scaffold E3 ligase complex via KLHL substrate adaptors for cancer therapy.

Targeted therapy has become increasingly important and indispensable in cancer therapy. Cullin3-RING ligases (CRL3) serve as essential executors for regulating protein homeostasis in cancer development, highlighting that CRL3 might be promising targets in various cancer treatment. However, how to design new targeted therapies by disrupting the function of CRL3 is poorly understood. Here, we focus on the substrate adaptors of CRL3, and carry out a systematical research on the function of Kelch-like (KLHL) family proteins. We have identified twenty-four KLHL proteins with function of tumor promotion and thirteen KLHL proteins with high clinical significance on cancer therapy. Furthermore, we have clarified the novel biological function of KLHL13 as a vital factor that contributes to malignant progression in lung cancer. Taken together, our findings reveal multiple potential therapeutical targets and provide evidence for targeting CRL3 via KLHL substrate adaptors for cancer therapy.

Phosphorylation regulates cullin-based ubiquitination in tumorigenesis.

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.

Discovery of a first-in-class CDK2 selective degrader for AML differentiation therapy.

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.

The role of autophagy in targeted therapy for acute myeloid leukemia.

Although molecular targeted therapies have recently displayed therapeutic effects in acute myeloid leukemia (AML), limited response and acquired resistance remain common problems. Numerous studies have associated autophagy, an essential degradation process involved in the cellular response to stress, with the development and therapeutic response of cancers including AML. Thus, we review studies on the role of autophagy in AML development and summarize the linkage between autophagy and several recurrent genetic abnormalities in AML, highlighting the potential of capitalizing on autophagy modulation in targeted therapy for AML.Abbreviations: AML: acute myeloid leukemia; AMPK: AMP-activated protein kinase; APL: acute promyelocytic leukemia; ATG: autophagy related; ATM: ATM serine/threonine kinase; ATO: arsenic trioxide; ATRA: all trans retinoic acid; BCL2: BCL2 apoptosis regulator; BECN1: beclin 1; BET proteins, bromodomain and extra-terminal domain family; CMA: chaperone-mediated autophagy; CQ: chloroquine; DNMT, DNA methyltransferase; DOT1L: DOT1 like histone lysine methyltransferase; FLT3: fms related receptor tyrosine kinase 3; FIS1: fission, mitochondrial 1; HCQ: hydroxychloroquine; HSC: hematopoietic stem cell; IDH: isocitrate dehydrogenase; ITD: internal tandem duplication; KMT2A/MLL: lysine methyltransferase 2A; LSC: leukemia stem cell; MDS: myelodysplastic syndromes; MTORC1: mechanistic target of rapamycin kinase complex 1; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; NPM1: nucleophosmin 1; PIK3C3/VPS34: phosphatidylinositol 3-kinase catalytic subunit type 3; PML: PML nuclear body scaffold; ROS: reactive oxygen species; RB1CC1/FIP200: RB1 inducible coiled-coil 1; SAHA: vorinostat; SQSTM1: sequestosome 1; TET2: tet methylcytosine dioxygenase 2; TKD: tyrosine kinase domain; TKI: tyrosine kinase inhibitor; TP53/p53: tumor protein p53; ULK1: unc-51 like autophagy activating kinase 1; VPA: valproic acid; WDFY3/ALFY: WD repeat and FYVE domain containing 3.

Protein phase separation: A novel therapy for cancer?

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.

Advances in differentiation therapy for osteosarcoma.

Differentiation therapy involves the use of agents that can induce differentiation in cancer cells, with the irreversible loss of tumour phenotype. The application of differentiation therapy in osteosarcoma has made progress because of a better understanding of the potential links between differentiation defects and tumorigenesis. Here, we review recent studies on differentiation therapy for osteosarcoma, describing a variety of differentiation inducers. By highlighting these examples of drug-induced osteosarcoma cell differentiation, we can acquire unique insights into not only osteosarcoma treatment, but also novel approaches to transform differentiating drugs into more effective therapies for other solid tumours.

CDK2 suppression synergizes with all-trans-retinoic acid to overcome the myeloid differentiation blockade of AML cells.

A characteristic feature of leukemia cells is a blockade of differentiation in cellular maturation. All-trans-retinoic acid (ATRA) has been successfully applied for the treatment of M3-type AML (APL, 10 %), but it fails to demonstrate a significant efficacy on the remaining patients with non-APL AML (90 %). Therefore, the research for strategies to extend the efficacy of ATRA-based therapy to non-APL AML is a key avenue of investigation. Here, we evaluate the synergetic effect of CDK2 inhibition and ATRA in AML both in vitro and in vivo. We have determined that both the CDK2 depletion and pharmacological inhibitor of CDK2 significantly sensitize three subtypes of AML cells (including two non-APL cells) to ATRA-induced cell differentiation. RNA-sequence results indicate that transcription activation of differentiation and maturation pathways plays an important role in this synergetic effect. Furthermore, the down-regulation of CDK2 sensitized AML cells to ATRA-induced engraftment prevention of leukemia cells in NOD-SCID mice and promotes the primary AML blasts differentiation when combined with ATRA. Thus, our work not only provides relevant experimental evidence for further validating CDK2 as a target for differentiation therapy, but also uncovers the future clinical application of CDK2 inhibitors in ATRA-based differentiation therapeutics for AML.

Post-translational modification of retinoic acid receptor alpha and its roles in tumor cell differentiation.

Retinoic acid (RA) is a well-known differentiation inducer that exerts its effects by binding to nuclear RA receptors. Retinoic acid receptor α (RARα), as an important nuclear RA receptor, is activated upon RA binding and facilitates the transcription of target genes related to differentiation, which ultimately initiates cell differentiation. Previous studies have found that the transcriptional activity of RARα is regulated by various post-translational modifications, which influence its DNA binding efficiency, transactivation ability and even lead to degradation. Post-translational modifications of RARα, as a consequence, play an important role in the RA-induced differentiation process. Therefore, in this review, we focus on recent advances in the understanding of how these modifications affect the activity of RARα as well as strategies to increase the differentiation effect of RA treatment in cancer cells based on RARα modifications, which may promote the development of novel effective differentiation therapies for cancer treatment.

FAT10: Function and Relationship with Cancer.

Posttranslational protein modifications are known to be extensively involved in cancer, and a growing number of studies have revealed that the ubiquitin-like modifier FAT10 is directly involved in cancer development. FAT10 was found to be highly upregulated in various cancer types, such as glioma, hepatocellular carcinoma, breast cancer and gastrointestinal cancer. Protein FAT10ylation and interactions with FAT10 lead to the functional change of proteins, including proteasomal degradation, subcellular delocalization and stabilization, eventually having significant effects on cancer cell proliferation, invasion, metastasis and even tumorigenesis. In this review, we summarized the current knowledge on FAT10 and discussed its biological functions in cancer, as well as potential therapeutic strategies based on the FAT10 pathway.

Inhibition of M2-like macrophages by all-trans retinoic acid prevents cancer initiation and stemness in osteosarcoma cells.

Emerging evidence indicates that M2-polarized tumor-associated macrophages (TAMs) directly participate in tumor initiation, progression and metastasis. However, to date, few studies have investigated novel strategies for inhibiting TAMs in order to overcome osteosarcoma. In this study, we reported that M2 macrophages were enriched in osteosarcoma tissues from patients, and M2-polarized TAMs enhanced cancer initiation and stemness of osteosarcoma cells, thereby establishing M2-polarized TAMs as a therapeutic target for blocking osteosarcoma formation. We also found that all-trans retinoic acid (ATRA) weakened TAM-induced osteosarcoma tumor formation by inhibiting M2 polarization of TAMs in vivo, and inhibited the colony formation, as well as sphere-formation capacity of osteosarcoma cells promoted by M2-type macrophages in vitro. Furthermore, M2-type macrophages enhanced cancer stem cells (CSCs) properties as assessed by increasing the numbers of CD117+Stro-1+ cells accompanied by the upregulation of CSC markers (CD133, CXCR4, Nanog, and Oct4), which could clearly be reduced by ATRA. Taken together, the results of this study demonstrated the role of M2-polarized TAMs in osteosarcoma initiation and stemness by activating CSCs, and indicated that ATRA treatment is a promising approach for treating osteosarcoma by preventing M2 polarization of TAMs.

2-Bromopalmitate sensitizes osteosarcoma cells to adriamycin-induced apoptosis via the modulation of CHOP.

Osteosarcoma is the most common primary malignant bone tumour, but the survival rate of patients has plateaued since the mid-1980s. Adriamycin is an integral component of the current first-line chemotherapies used for osteosarcoma, but dose-dependent severe side effects often limit its clinical application. Here, we propose a potential combination regimen in which adriamycin plus 2-bromopalmitate, a palmitoylation inhibitor, exhibited powerful therapeutic effects on osteosarcoma. First, 2-bromopalmitate strongly increased the proliferation inhibition of adriamycin in both human osteosarcoma cell lines and primary osteosarcoma cells. Adriamycin-induced apoptosis in osteosarcoma cells was enhanced when synergized with 2-bromopalmitate. Our study indicated that the reactive oxygen species scavenger NAC and GSH could largely reverse the apoptosis induced by adriamycin combined with 2-bromopalmitate, demonstrating that reactive oxygen species played an essential role in this combination therapy. Moreover, CHOP was remarkably elevated in the combination group, and silencing of CHOP almost completely blocked the apoptosis induced by the combination of 2-bromopalmitate and adriamycin. Taken together, our study provides a prospective therapeutic strategy to eliminate osteosarcoma, which is propitious to clinical combination therapy development.

Ubiquitin-dependent degradation of CDK2 drives the therapeutic differentiation of AML by targeting PRDX2.

A distinct hallmark of acute myeloid leukemia (AML) is the arrest of leukemic myeloblasts at an immature stage of development. Therapies that overcome differentiation arrest have emerged as a powerful strategy for treating AML, but targeting leukemia differentiation remains challenging, mainly because of an incomplete mechanistic understanding of the process. Here, we unveil a new role for cyclin-dependent kinase 2 (CDK2) in blocking myeloid differentiation in AML. We show that among several interphase CDK, only CDK2 undergoes ubiquitin-dependent proteasome degradation, which is accompanied by AML cell differentiation. By using the yeast 2-hybrid system and functional analyses, KLHL6 was identified as a specific E3 ubiquitin ligase regulating the degradation of CDK2. Importantly, inhibiting CDK2, but not other cyclin-dependent kinases CDK1/4/6, effectively induced granulocytic differentiation in AML cell lines and 5 major subtypes of primary patient-derived AML samples. Mechanistically, CDK2 depletion led to the reactivation of differentiation pathway translation, and the differentiation blockade function of CDK2 may be achieved directly by maintaining the activity of PRDX2. Finally, CDK2 depletion arrested tumor growth of AML cells in nude mice and extended survival in both AML cell line and PDX-AML cells derived xenograft mouse models. Thus, our work not only provides experimental evidence for validating CDK2 as a potential therapeutic target for differentiation, but also uncovers the biological function of the CDK2-PRDX2 axis in blocking AML differentiation.