Cucurbitacin C suppresses the progression of pancreatic ductal adenocarcinoma via inhibition of the cGMP-PKG-VASP axis

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most devastating diseases; it has a considerably poor prognosis and may become the second most lethal malignancy in the next 10 years. Chemotherapeutic resistance is common in PDAC; thus, it is necessary to exploit effective alternative drugs. In recent years, traditional folk medicines and their extracts have shown great potential in cancer treatment. The seed of Lagenaria siceraria (Molina) Standl. is a traditional medicine in Asia. Because of its analgesic effects and ability to reduce swelling, it is often used as an adjuvant treatment for abdominal tumors. Cucurbitacin compounds are extracts abundant in Lagenaria siceraria (Molina) Standl. Here, we found that cucurbitacin C (CuC), a member of the cucurbitacin family, has apparent anti-PDAC therapeutic properties. CuC decreased the viability and suppressed the proliferation of PDAC cells in a time- and dose-dependent manner. Further studies revealed that CuC inhibited cell migration and invasion by inhibiting epithelial-mesenchymal transition (EMT). In addition, G2/M arrest was induced, and the apoptotic pathway was activated. Transcriptomic and bioinformatic analyses showed that CuC inhibited the cGMP-PKG-VASP axis, increasing the content of cGMP to restore tumor characteristics. The antitumor activity of CuC in vivo was verified through animal experiments, and no obvious side effects were observed. Overall, our study indicates a candidate therapeutic compound for PDAC that is worthy of further development.

Discovery of Novel Oxazepine Derivatives as Akt/ROCK Inhibitors for Growth Arrest and Differentiation Induction in Neuroblastoma Treatment

Patients with high-risk neuroblastoma face limited treatment choices, typically involving a combination of cytotoxic and differentiation maintenance therapies due to a scarcity of drugs. Evidence suggests that targeted inhibitors may provide opportunities for inducing neuroblastoma differentiation while inhibiting proliferation. Here, we demonstrate the synergistic effect of inhibiting Akt and ROCK in antineuroblastoma and present the design and discovery of a new Akt/ROCK inhibitor, B12. It displays strong antiproliferative effects and excellent differentiation inducing activity against Neuro2a cells. Treatment with B12 results in the arrest of G0/G1 cell cycles, a significant decrease in N-myc protein level, and an increase in differentiation markers. The administration of B12 effectively suppresses xenograft tumor growth and promotes differentiation. Overall, the discovery of B12 based on the Akt/ROCK dual inhibition strategy may provide hope for the development of more effective and targeted therapies for this challenging disease.

Mutations in DARS2 result in global dysregulation of mRNA metabolism and splicing

Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is a rare neurological disorder caused by the mutations in the DARS2 gene, which encodes the mitochondrial aspartyl-tRNA synthetase. The objective of this study was to understand the impact of DARS2 mutations on cell processes through evaluation of LBSL patient stem cell derived cerebral organoids and neurons. We generated human cerebral organoids (hCOs) from induced pluripotent stem cells (iPSCs) of seven LBSL patients and three healthy controls using an unguided protocol. Single cells from 70-day-old hCOs were subjected to SMART-seq2 sequencing and bioinformatic analysis to acquire high-resolution gene and transcript expression datasets. Global gene expression analysis demonstrated dysregulation of a number of genes involved in mRNA metabolism and splicing processes within LBSL hCOs. Importantly, there were distinct and divergent gene expression profiles based on the nature of the DARS2 mutation. At the transcript level, pervasive differential transcript usage and differential spliced exon events that are involved in protein translation and metabolism were identified in LBSL hCOs. Single-cell analysis of DARS2 (exon 3) showed that some LBSL cells exclusively express transcripts lacking exon 3, indicating that not all LBSL cells can benefit from the "leaky" nature common to splice site mutations. At the gene- and transcript-level, we uncovered that dysregulated RNA splicing, protein translation and metabolism may underlie at least some of the pathophysiological mechanisms in LBSL. To confirm hCO findings, iPSC-derived neurons (iNs) were generated by overexpressing Neurogenin 2 using lentiviral vector to study neuronal growth, splicing of DARS2 exon 3 and DARS2 protein expression. Live cell imaging revealed neuronal growth defects of LBSL iNs, which was consistent with the finding of downregulated expression of genes related to neuronal differentiation in LBSL hCOs. DARS2 protein was downregulated in iNs compared to iPSCs, caused by increased exclusion of exon 3. The scope and complexity of our data imply that DARS2 is potentially involved in transcription regulation beyond its canonical role of aminoacylation. Nevertheless, our work highlights transcript-level dysregulation as a critical, and relatively unexplored, mechanism linking genetic data with neurodegenerative disorders.

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 {AuQ: Edit OK?}, 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.

Search for Subsolar-Mass Binaries in the First Half of Advanced LIGO's and Advanced Virgo's Third Observing Run

We report on a search for compact binary coalescences where at least one binary component has a mass between 0.2  M_{⊙} and 1.0  M_{⊙} in Advanced LIGO and Advanced Virgo data collected between 1 April 2019 1500 UTC and 1 October 2019 1500 UTC. We extend our previous analyses in two main ways: we include data from the Virgo detector and we allow for more unequal mass systems, with mass ratio q≥0.1. We do not report any gravitational-wave candidates. The most significant trigger has a false alarm rate of 0.14  yr^{-1}. This implies an upper limit on the merger rate of subsolar binaries in the range [220-24200]  Gpc^{-3} yr^{-1}, depending on the chirp mass of the binary. We use this upper limit to derive astrophysical constraints on two phenomenological models that could produce subsolar-mass compact objects. One is an isotropic distribution of equal-mass primordial black holes. Using this model, we find that the fraction of dark matter in primordial black holes in the mass range 0.2  M_{⊙}<m_{PBH}<1.0  M_{⊙} is f_{PBH}≡Ω_{PBH}/Ω_{DM}≲6%. This improves existing constraints on primordial black hole abundance by a factor of ∼3. The other is a dissipative dark matter model, in which fermionic dark matter can collapse and form black holes. The upper limit on the fraction of dark matter black holes depends on the minimum mass of the black holes that can be formed: the most constraining result is obtained at M_{min}=1  M_{⊙}, where f_{DBH}≡Ω_{DBH}/Ω_{DM}≲0.003%. These are the first constraints placed on dissipative dark models by subsolar-mass analyses.

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.

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.

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.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

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.

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.

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.

A Clinical Genomics-Guided Prioritizing Strategy Enables Selecting Proper Cancer Cell Lines for Biomedical Research

Selecting appropriate cell lines to represent a disease is crucial for the success of biomedical research, because the usage of less relevant cell lines could deliver misleading results. However, systematic guidance on cell line selection is unavailable. Here we developed a clinical Genomics-guided Prioritizing Strategy for Cancer Cell Lines (CCL-cGPS) and help to guide this process. Statistical analyses revealed CCL-cGPS selected cell lines were among the most appropriate models. Moreover, we observed a linear correlation between the drug response and CCL-cGPS score of cell lines for breast and thyroid cancers. Using RT4 cells selected by CCL-GPS, we identified mebendazole and digitoxin as candidate drugs against bladder cancer and validate their promising anticancer effect through in vitro and in vivo experiments. Additionally, a web tool was developed. In conclusion, CCL-cGPS bridges the gap between tumors and cell lines, presenting a helpful guide to select the most suitable cell line models.

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Cell lines were ranked by the resemblance of transcriptional signatures to tumors

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Among 44 tumor subtypes, CCL-cGPS provides proper cell lines for each subtype

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CCL-cGPS was verified by the computational analysis, in vitro and in vivo assays

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A web tool was developed to guide the selection of the most suitable cell lines

Association of high-sensitivity C-reactive protein and long-term mortality may differ from lipoprotein(a) levels among patients undergoing coronary angiography

Background

The use of high-sensitivity C-reactive protein (hs-CRP) as an inflammation biomarker in predicting long-term mortality remains controversial. We aimed to investigate whether the association of hs-CRP with long-term mortality differs from another inflammation biomarker, lipoprotein(a), in patients undergoing coronary angiography (CAG).

Methods

A total of 2422 patients undergoing CAG were included in the final analysis from a prospective, observational study. We divided them into 4 groups according to hs-CRP level (high ≥4.8 mg/l, low &lt;4.8 mg/l) and lipoprotein(a) level (high ≥17 mg/dl, low &lt;17 mg/dl).

Results

The overall incidence of all-cause long-term mortality was 133/2422 (5.5%). In the high lipoprotein(a) group, after adjusting for LDL-cholesterol concentration (LDL-C), age, sex, smoking status, diabetes mellitus and estimated glomerular filtration rate (eGFR), a high hs-CRP level was an independent predictor of all-cause long-term mortality (hazard ratio: 2.01; 95% CI: 1.13–3.54; p=0.02). In the low lipoprotein(a) group, a similar result was not found (hazard ratio: 1.42; 95% CI: 0.92–2.01; p=0.24).

Conclusions

Our data suggested that the association of hs-CRP with all-cause long-term mortality may differ from lipoprotein(a) levels among patients undergoing CAG. In addition to hs-CRP, a high lipoprotein(a) level might be a simultaneous intervention target for improving long-term prognosis in the future.

Funding Acknowledgement

Type of funding source: None

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.

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.

Machado-Joseph Deubiquitinases: From Cellular Functions to Potential Therapy Targets

Ubiquitination is known as important post-translational modification in cancer-related pathways. Human deubiquitinases (DUBs), with functions of modulating the ubiquitination process, are a family with about 100 proteins. They mainly function by cutting ubiquitin chains of the substrates. The Machado-Joseph domain-containing proteases (MJDs) is one of the sub-families of DUBs, consisting of four members, namely, Ataxin-3, Ataxin-3L, JOSD1, and JOSD2. Recent studies have provided new insights into biological functions of MJDs in the progression of Machado-Joseph disease or cancer diseases. In this review, we summarized the cellular functions and regulatory mechanisms of MJDs in Machado-Joseph disease and cancer pathways. Furthermore, we summarized MJDs genetic alterations in different human cancers by exploring the public databases (cBioportal). The aim of this review is to provide a comprehensive account based on our current knowledge about emerging insights into MJDs in physiology and disease, which might shed light on fundamental biological questions and promise to provide a potential target for therapeutic intervention.

ZDHHC12-mediated claudin-3 S-palmitoylation determines ovarian cancer progression

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.

Cellular Senescence and Anti-Cancer Therapy

BACKGROUND

Cellular senescence is generally understood as a permanent cell cycle arrest stemming from different causes. The mechanism of cellular senescence-induced cell cycle arrest is complex, involving interactions between telomere shortening, inflammations and cellular stresses. In recent years, a growing number of studies have revealed that cellular senescence could mediate the cancer progression of neighboring cells, but this idea is controversial and contradictory evidence argues that cellular senescence also contributes to tumor suppression.

OBJECTIVE

Given that the complicated role of senescence in various physiological and pathological scenarios, we try to clarify the precise contribution role of cellular senescence to tumor progression.

METHODS

Search for the information in a large array of relevant articles to support our opinion.

RESULTS

We discuss the relatively widespread occurrence of cellular senescence in cancer treatment and identify the positive and negative side of senescence contributed to tumor progression.

CONCLUSION

We argue that the availability of pro-senescence therapy could represent as a promising regimen for managing cancer disease, particularly with regard to the poor clinical outcome obtained with other anticancer therapies.

USP10 Promotes Proliferation of Hepatocellular Carcinoma by Deubiquitinating and Stabilizing YAP/TAZ

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.

DJ-1 suppresses ferroptosis through preserving the activity of S-adenosyl homocysteine hydrolase

Ferroptosis is a newly characterized form of regulated cell death mediated by iron-dependent accumulation of lipid reactive oxygen species and holds great potential for cancer therapy. However, the molecular mechanisms underlying ferroptosis remain largely elusive. In this study, we define an integrative role of DJ-1 in ferroptosis. Inhibition of DJ-1 potently enhances the sensitivity of tumor cells to ferroptosis inducers both in vitro and in vivo. Metabolic analysis and metabolite rescue assay reveal that DJ-1 depletion inhibits the transsulfuration pathway by disrupting the formation of the S-adenosyl homocysteine hydrolase tetramer and impairing its activity. Consequently, more ferroptosis is induced when homocysteine generation is decreased, which might be the only source of glutathione biosynthesis when cystine uptake is blocked. Thus, our findings show that DJ-1 determines the response of cancer cells to ferroptosis, and highlight a candidate therapeutic target to potentially improve the effect of ferroptosis-based antitumor therapy.

Unexpected cell type-dependent effects of autophagy on polyglutamine aggregation revealed by natural genetic variation in C. elegans

Background

Monogenic protein aggregation diseases, in addition to cell selectivity, exhibit clinical variation in the age of onset and progression, driven in part by inter-individual genetic variation. While natural genetic variants may pinpoint plastic networks amenable to intervention, the mechanisms by which they impact individual susceptibility to proteotoxicity are still largely unknown.

Results

We have previously shown that natural variation modifies polyglutamine (polyQ) aggregation phenotypes in C. elegans muscle cells. Here, we find that a genomic locus from C. elegans wild isolate DR1350 causes two genetically separable aggregation phenotypes, without changing the basal activity of muscle proteostasis pathways known to affect polyQ aggregation. We find that the increased aggregation phenotype was due to regulatory variants in the gene encoding a conserved autophagy protein ATG-5. The atg-5 gene itself conferred dosage-dependent enhancement of aggregation, with the DR1350-derived allele behaving as hypermorph. Surprisingly, increased aggregation in animals carrying the modifier locus was accompanied by enhanced autophagy activation in response to activating treatment. Because autophagy is expected to clear, not increase, protein aggregates, we activated autophagy in three different polyQ models and found a striking tissue-dependent effect: activation of autophagy decreased polyQ aggregation in neurons and intestine, but increased it in the muscle cells.

Conclusions

Our data show that cryptic natural variants in genes encoding proteostasis components, although not causing detectable phenotypes in wild-type individuals, can have profound effects on aggregation-prone proteins. Clinical applications of autophagy activators for aggregation diseases may need to consider the unexpected divergent effects of autophagy in different cell types.

The SIRT2-mediated deacetylation of AKR1C1 is required for suppressing its pro-metastasis function in Non-Small Cell Lung Cancer

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.

Deubiquitinating enzyme USP10 promotes hepatocellular carcinoma metastasis through deubiquitinating and stabilizing Smad4 protein

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.

Stress granule: A promising target for cancer treatment

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.

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.

Upregulation of miR-489-3p and miR-630 inhibits oxaliplatin uptake in renal cell carcinoma by targeting OCT2

Renal cell carcinoma (RCC) is one of the most common malignant tumors affecting the urogenital system, accounting for 90% of renal malignancies. Traditional chemotherapy options are often the front-line choice of regimen in the treatment of patients with RCC, but responses may be modest or limited due to resistance of the tumor to anticarcinogen. Downregulated expression of organic cation transporter OCT2 is a possible mechanism underlying oxaliplatin resistance in RCC treatment. In this study, we observed that miR-489-3p and miR-630 suppress OCT2 expression by directly binding to the OCT2 3'-UTR. Meanwhile, via 786-O-OCT2-miRNAs stable expression cell models, we found that miRNAs could repress the classic substrate 1-methyl-4-phenylpyridinium (MPP⁺), fluorogenic substrate N,N-dimethyl-4-(2-pyridin-4-ylethenyl) aniline (ASP⁺), and oxaliplatin uptake by OCT2 both in vitro and in xenografts. In 33 clinical samples, miR-489-3p and miR-630 were significantly upregulated in RCC, negatively correlating with the OCT2 expression level compared to that in adjacent normal tissues, using tissue microarray analysis and qPCR validation. The increased binding of c-Myc to the promoter of pri-miR-630, responsible for the upregulation of miR-630 in RCC, was further evidenced by chromatin immunoprecipitation and dual-luciferase reporter assay. Overall, this study indicated that miR-489-3p and miR-630 function as oncotherapy-obstructing microRNAs by directly targeting OCT2 in RCC.

STAT3 dictates β-cell apoptosis by modulating PTEN in streptozocin-induced hyperglycemia

Insufficient pancreatic β-cell mass or insulin-producing β-cells are implicated in all forms of diabetes mellitus. However, the molecular mechanisms underlying β-cell destruction are complex and not fully defined. Here we observed that activation of STAT3 is intensely and specifically inhibited in β-cells under hyperglycemic conditions. By knocking out STAT3 specifically in mouse β-cells, we found that the loss of STAT3 sensitized mice to three low doses of STZ stimulation resulting in hyperglycemia. Mechanistically, accumulating PTEN, induced by STAT3 deficiency, directly represses phosphorylation of AKT, which negatively modulates transcription factor activation, dysregulates β-cell function, positively promotes apoptotic signaling, and finally induces β-cell apoptosis. Notably, the defective secretion of insulin and β-cells apoptosis was completely rescued by PTEN ablation in STAT3-null islets or PTEN inhibitor bpv(phen) treatment. Thus our data suggest that STAT3 is a vital modulator of β-cell survival and function, highlighting a critical role for STAT3 in the negative regulation of PTEN-AKT signaling pathway associated with β-cell dysfunction and apoptosis.

Targeting slug-mediated non-canonical activation of c-Met to overcome chemo-resistance in metastatic ovarian cancer cells

Metastasis-associated drug resistance accounts for high mortality in ovarian cancer and remains to be a major barrier for effective treatment. In this study, SKOV3/T4, a metastatic subpopulation of ovarian cancer SKOV3 cells, was enriched to explore potential interventions against metastatic-associated drug resistance. Quantitative genomic and functional analyses were performed and found that slug was significantly increased in the SKOV3/T4 subpopulation and contributed to the high resistance of SKOV3/T4. Further studies showed that slug activated c-Met in a ligand-independent manner due to elevated levels of fibronectin and provoked integrin α V function, which was confirmed by the significant correlation of slug and p-Met levels in 121 ovarian cancer patient samples. Intriguingly, c-Met inhibitor(s) exhibited greatly enhanced anti-cancer effects in slug-positive ovarian cancer models both in vitro and in vivo. Additionally, IHC analyses revealed that slug levels were highly correlated with reduced survival of ovarian cancer patients. Taken together, this study not only uncovers the critical roles of slug in drug resistance in ovarian cancer but also highlights a promising therapeutic strategy by targeting the noncanonical activation of c-Met in slug-positive ovarian cancer patients with poor prognosis.

LncRNA-MM2P Identified as a Modulator of Macrophage M2 Polarization

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.

Immune cells in the tumour: new routes of retinoids for chemoprevention and chemotherapeutics

Retinoids, vitamin A and its natural and synthetic analogues have various functions, including being involved in cell proliferation and differentiation and participating in the formation of vertebrate morphology. In addition, they may activate certain tumour suppressor genes that then act as tumour inhibitors. In the past decades, retinoids have been regarded as promising chemotherapeutic and chemopreventive agents; however, their mechanisms are still not fully understood. Immune cells that participate in or are associated with the immune response play vital roles in the initiation and development of many cancers. Interestingly, recent studies have demonstrated that retinoids can also exert various effects on immune cells including macrophages, T cells and dendritic cells in tumour tissues to execute anti-tumour actions, providing new insights into chemoprevention and chemotherapeutics. In this review, we focus on the effects of retinoids on immune cells in the tumour, which may provide new approaches for antineoplastic strategies.

Inhibition of Ubiquitin-Specific Proteases as a Novel Anticancer Therapeutic Strategy

Dysfunction or dysregulation of the ubiquitin proteasome system (UPS) is closely related to tumorigenesis and the development of multiple cancers. Targeting the UPS provides a new anticancer therapeutic strategy, but clinically available UPS-targeted inhibitors, including lenalidomide and bortezomib, are limited to treat solid tumors. Under physiological conditions, deubiquitinases or deubiquitinating enzymes (DUBs) play vital roles in the UPS by removing ubiquitin from substrate proteins and regulating their proteasomal degradation and sub-localization, thus maintaining the balance between ubiquitination and deubiquitination for protein quality control and homeostasis. The aberrant expression or function of DUBs generally leads to the occurrence and progression of a series of disorders, including malignant tumors. Therefore, targeting DUBs is a novel anticancer therapeutic strategy. Ubiquitin-specific proteases (USPs) are the largest subfamily of DUBs which have attracted considerable interest as anticancer targets. Most of USPs are abnormally activated or expressed in a variety of malignant tumors or in the tumor microenvironment, making them ideal anticancer target candidates, which indicates that USPs inhibitors may be a class of potential anticancer therapeutic agents. However, there are no relevant inhibitors targeting USPs have entered clinical trial so far. In this review, we will summarize the roles and mechanisms of USPs in malignant transformation and progression as well as recent advances of small-molecule inhibitors targeting USPs.

[Factors affecting stability after fixed orthodontic treatment]

Objective: To analyze factors affecting stability after fixed orthodontic treatment. Methods: Five hundred and forty-four patients who had finished fixed orthodontic treatment more than two years in First Department of Orthodontics, China Medical University from January, 2000 to December, 2017 were investigated and the rate of regular revisit was counted. The data of 288 patients were successfully collected by calling or sending text messages and the rate of standard use of retainers as prescribed (patients wore retainers for 24 months or longer) was counted. According to the variation of peer assessment rating (PAR) index at the start of retention and the time the data collected, the patients were divided into relapse group (variation of PAR index >5) and non-relapse group (variation of PAR index ≤5). Difference significance analysis and multiple-factor logistic regression analysis were used. Sixty patients wearing retainers well were collected and the curative effects of Hawley retainer and vacuum formed retainer (VFR) were compared, which included overbite, overjet, maxillary irregularity index, mandibular irregularity index, width betwenn canine and width between first molar. Results: The rate of regular revisit was 41.0% (223/544). Two hundred and one of 288 patients (69.8%) who were visited successfully had regular revisit, and 60.4%(174/288) of the patients wore retainers well; 30.2% (87/288) of the patients who were visited successfully didn't have regular revisit, and 10.4% (30/288) of the patients wore retainers well. Difference significance analysis showed that there was highly significant difference between relapse group and non-relapse group in the type of retainer and duration of retention (P<0.01). One hundred and forty of 224 patients (62.5%) in non-relapse group and 37.5% (24/64) of the patients in relapse group used VFR, and the duration of retention in non-relapse group was significantly longer than that in relapse group (P<0.01). Multiple-factor Logistic regression analysis showed that wearing Hawley retainers (OR=3.067, P<0.05) was the risk factor influencing relapse. The duration of retention (OR=0.832, P<0.01) was the protective factor influencing relapse. Independent-sample t test indicated that the variations of maxillary [(0.82±0.36) mm] and mandibular [(1.05±0.22) mm] irregularity index in Hawley retainer group were larger than maxillary [(0.64±0.29) mm] and mandibular [(0.72±0.35) mm)] irregularity index in VFR group, respectively. The differences between the two groups were significant (P<0.05). Conclusions: Duration of retention was implicated in stability after orthodontic treatment. VFR had better effect in the aspects of irregularity index than Hawley retainer.

Multikinase Inhibitor CT-707 Targets Liver Cancer by Interrupting the Hypoxia-Activated IGF-1R-YAP Axis

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.

Inhibition of KLF4 by Statins Reverses Adriamycin-Induced Metastasis and Cancer Stemness in Osteosarcoma Cells

Adriamycin-based combination chemotherapy is the standard first-line treatment for osteosarcoma, but tumor recurrence and metastasis occurs in most cases. Recent evidence suggests that microenvironmental stress such as chemotherapy can lead to the enrichment of cancer stem cells (CSCs), which result in cancer metastasis, recurrence, and drug resistance. However, the exact mechanisms underlying this phenomenon and how to target CSCs are still open questions. Herein, we report that Adriamycin treatment induces a stem-like phenotype and promotes metastatic potential in osteosarcoma cells through upregulating KLF4. KLF4 knockdown blocks Adriamycin-induced stemness phenotype and metastasis capacity. We further screen that statins remarkably reverse Adriamycin-induced CSC properties and metastasis by downregulating KLF4. Most strikingly, simvastatin severely impaired Adriamycin-enhanced tumorigenesis of KHOS/NP cells in vivo. These data suggest that Adriamycin-based chemotherapeutics may simulate CSCs through activation of KLF4 signaling and that selective inhibition of KLF4 with statins should be considered in the development of osteosarcoma therapeutics.

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Adriamycin treatment induces a stemness phenotype in osteosarcoma cells

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KLF4 is a key transcriptional regulator of ADR-induced osteosarcoma cancer stemness

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Simvastatin reverses ADR-induced CSC properties by downregulating KLF4

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Simvastatin abolishes ADR-enhanced tumorigenesis of KHOS/NP cells in vivo

All-Trans Retinoic Acid Prevents Osteosarcoma Metastasis by Inhibiting M2 Polarization of Tumor-Associated Macrophages

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.