Chemical screen identifies shikonin as a broad DNA damage response inhibitor that enhances chemotherapy through inhibiting ATM and ATR

Shikonin and chitosan-silver nanoparticles synergize against triple-negative breast cancer through RIPK3-triggered necroptotic immunogenic cell death

Necroptotic immunogenic cell death (ICD) can activate the human immune system to treat the metastasis and recurrence of triple-negative breast cancer (TNBC). However, developing the necroptotic inducer and precisely delivering it to the tumor site is the key issue. Herein, we reported that the combination of shikonin (SHK) and chitosan silver nanoparticles (Chi-Ag NPs) effectively induced ICD by triggering necroptosis in 4T1 cells. Moreover, to address the lack of selectivity of drugs for in vivo application, we developed an MUC1 aptamer-targeted nanocomplex (MUC1@Chi-Ag@CPB@SHK, abbreviated as MUC1@ACS) for co-delivering SHK and Chi-Ag NPs. The accumulation of MUC1@ACS NPs at the tumor site showed a 6.02-fold increase compared to the free drug. Subsequently, upon reaching the tumor site, the acid-responsive release of SHK and Chi-Ag NPs from MUC1@ACS NPs cooperatively induced necroptosis in tumor cells by upregulating the expression of RIPK3, p-RIPK3, and tetrameric MLKL, thereby effectively triggering ICD. The sequential maturation of dendritic cells (DCs) subsequently enhanced the infiltration of CD8+ and CD4+ T cells in tumors, while inhibiting regulatory T cells (Treg cells), resulting in the effective treatment of primary and distal tumor growth and the inhibition of TNBC metastasis. This work highlights the importance of nanoparticles in mediating drug interactions during necroptotic ICD.

Shikonin blocks CAF-induced TNBC metastasis by suppressing mitochondrial biogenesis through GSK-3β/NEDD4-1 mediated phosphorylation-dependent degradation of PGC-1α

BACKGROUND

Triple-negative breast cancer (TNBC) is characterized by its high metastatic potential, which results in poor patient survival. Cancer-associated fibroblasts (CAFs) are crucial in facilitating TNBC metastasis via induction of mitochondrial biogenesis. However, how to inhibit CAF-conferred mitochondrial biogenesis is still needed to explore.

METHODS

We investigated metastasis using wound healing and cell invasion assays, 3D-culture, anoikis detection, and NOD/SCID mice. Mitochondrial biogenesis was detected by MitoTracker green FM staining, quantification of mitochondrial DNA levels, and blue-native polyacrylamide gel electrophoresis. The expression, transcription, and phosphorylation of peroxisome-proliferator activated receptor coactivator 1α (PGC-1α) were detected by western blotting, chromatin immunoprecipitation, dual-luciferase reporter assay, quantitative polymerase chain reaction, immunoprecipitation, and liquid chromatography-tandem mass spectrometry. The prognostic role of PGC-1α in TNBC was evaluated using the Kaplan-Meier plotter database and clinical breast cancer tissue samples.

RESULTS

We demonstrated that PGC-1α indicated lymph node metastasis, tumor thrombus formation, and poor survival in TNBC patients, and it was induced by CAFs, which functioned as an inducer of mitochondrial biogenesis and metastasis in TNBC. Shikonin impeded the CAF-induced PGC-1α expression, nuclear localization, and interaction with estrogen-related receptor alpha (ERRα), thereby inhibiting PGC-1α/ERRα-targeted mitochondrial genes. Mechanistically, the downregulation of PGC-1α was mediated by synthase kinase 3β-induced phosphorylation of PGC-1α at Thr295, which associated with neural precursor cell expressed developmentally downregulated 4e1 recognition and subsequent degradation by ubiquitin proteolysis. Mutation of PGC-1α at Thr295 negated the suppressive effects of shikonin on CAF-stimulated TNBC mitochondrial biogenesis and metastasis in vitro and in vivo.

CONCLUSIONS

Our findings indicate that PGC-1α is a viable target for blocking TNBC metastasis by disrupting mitochondrial biogenesis, and that shikonin merits potential for treatment of TNBC metastasis as an inhibitor of mitochondrial biogenesis through targeting PGC-1α.

Discovery of the first ataxia telangiectasia and Rad3-related (ATR) degraders for cancer treatment

The first examples of ataxia telangiectasia and Rad3-related (ATR) PROTACs were designed and synthesized. Among them, the most potent degrader, ZS-7, demonstrated selective and effective ATR degradation in ATM-deficient LoVo cells, with a DC50 value of 0.53 μM. Proteasome-mediated ATR degradation by ZS-7 lasted approximately 12 h after washout in the LoVo cell lines. Notably, ZS-7 demonstrated reasonable PK profiles and, as a single agent or in combination with cisplatin, showed improved antitumor activity and safety profiles compared with the parent inhibitor AZD6738 in a xenograft mouse model of LoVo human colorectal cancer cells upon intraperitoneal (i.p.) administration.

Adjuvant role of Salvia miltiorrhiza bunge in cancer chemotherapy: A review of its bioactive components, health-promotion effect and mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Chemotherapy is a common cancer treatment strategy. However, its effectiveness is constrained by toxicity and adverse effects. The Lamiaceae herb Salvia miltiorrhiza Bunge has a long history of therapeutic use in the treatment of blood stasis illnesses, which are believed by traditional Chinese medicine to be connected to cancer.

AIM OF THE STUDY

This review summarized the common toxicity of chemotherapy and the potential chemo-adjuvant effect and mechanisms of active ingredients from S. miltiorrhiza, hoping to provide valuable information for the development and application of S. miltiorrhiza resources.

MATERIALS AND METHODS

The literatures were retrieved from PubMed, Web of Science, Baidu Scholar and Google Scholar databases from 2002 to 2022. The inclusion criteria were studies reporting that S. miltiorrhiza or its constituents enhanced the efficiency of chemotherapy drugs or reduced the side effects.

RESULTS

Salvianolic acid A, salvianolic acid B, salvianolic acid C, rosmarinic acid, tanshinone I, tanshinone IIA, cryptotanshinone, dihydrotanshinone I and miltirone are the primary adjuvant chemotherapy components of S. miltiorrhiza. The mechanisms mainly involve inhibiting proliferation, metastasis, and angiogenesis, inducing apoptosis, regulating autophagy and tumor microenvironment. In addition, they also improve chemotherapy drug-induced side effects.

CONCLUSIONS

The bioactive compounds of S. miltiorrhiza are shown to inhibit proliferation, metastasis, and angiogenesis, induce apoptosis and autophagy, regulate immunity and tumor microenvironment when combined with chemotherapy drugs. However, further clinical studies are required to validate the current studies.

The Biological Assessment of Shikonin and β,β-dimethylacrylshikonin Using a Cellular Myxofibrosarcoma Tumor Heterogeneity Model

Myxofibrosarcoma (MFS) is a subtype of soft tissue sarcoma of connective tissue, which is characterized by large intra-tumor heterogeneity. Therapy includes surgical resection. Additional chemotherapy is of limited effect. In this study, we demonstrated the potent anticancer activity of shikonin derivatives in our MFS cellular model of tumor heterogeneity for developing a new therapeutic approach. The impact of shikonin and β,β-dimethylacrylshikonin (DMAS) on viability, apoptotic induction, MAPK phosphorylation, and DNA damage response were analyzed by means of two human MFS cell lines, MUG-Myx2a and MUG-Myx2b, derived from a singular tumor tissue specimen. MFS cells showed a dose-dependent inhibition of cell viability and a significant induction of apoptosis. Treatment with shikonin derivatives caused an inhibition of pSTAT3 and an increase in pAKT, pERK, pJNK, and pp38. DMAS and shikonin inhibited the activation of the two master upstream regulators of the DNA damage response, ATR and ATM. MUG-Myx2b, which contains an additional PTEN mutation, was more sensitive in some targets. These data demonstrate the significant antitumorigenic effect of shikonin derivatives in MFS and highlight the importance of intra-tumor heterogeneity in treatment planning.

Target protein degradation by protacs: A budding cancer treatment strategy

Cancer is one of the most common causes of death. So, its lethal effect increases with time. Near about hundreds of cancers are known in humans. Cancer treatment is done to cure or prolonged remission, and shrinkage of the tumor. Cytotoxic agents, biological agents/targeted drugs, hormonal drugs, surgery, radiotherapy/proton therapy, chemotherapy, immunotherapy, and gene therapy are currently used in the treatment of cancer but their cost is high and cause various side effects. Seeing this, some new targeted strategies such as PROTACs are the need of the time. Proteolysis targeting chimera (PROTAC) has become one of the most discussed topics regarding cancer treatment. Few of the PROTAC molecules are in the trial phases. PROTACs have many advantages over other strategies such as modularity, compatibility, sub-stoichiometric activity, acting on undruggable targets, molecular design, and acts on intracellular targets, selectivity and specificity can be recruited for any cancer, versatility, and others. PROTACs are having some unclear questions on their pharmacokinetics, heavy-molecular weight, etc. PROTACs are anticipated to bring about a conversion in current healthcare and will emerge as booming treatments. In this review article we summarize PROTACs, their mechanism of action, uses, advantages, disadvantages, challenges, and future aspects for the successful development of potent PROTACs as a drug strategy.

Drug release and solubility properties of two zeolitic metal-organic frameworks influenced by their hydrophobicity/hydrophilicity

Metal-organic frameworks (MOFs) have shown significant potential for drug delivery applications. However, there remains a scarcity of comprehensive research addressing the influence of surface properties of MOFs on drug release kinetics and drug solubility. This study focuses on examining the influence of MOFs hydrophilicity and hydrophobicity on the controlled release and solubility of drugs. To achieve this, we prepared drug-loaded nanoparticles through in situ synthesis and created a drug-MOF co-amorphous system using the ball milling technique. Under neutral conditions, the hydrophilic MOF-based drug delivery system demonstrated a comparatively slower drug release profile than its hydrophobic counterpart. This observation suggests that the hydrophilic system holds promise in mitigating drug side effects by enabling improved control over drug release. The implementation of hydrophobic MOFs in co-amorphous systems yields a more pronounced effect on enhancing solubility compared to hydrophilic MOFs. This study offers valuable insights for achieving optimal drug release kinetics and solubility by delicately manipulating surface properties of MOFs.

MYO10 regulates genome stability and cancer inflammation through mediating mitosis

Genomic instability can promote inflammation and tumor development. Previous research revealed an unexpected layer of regulation of genomic instability by a cytoplasmic protein MYO10; however, the underlying mechanism remained unclear. Here, we report a protein stability-mediated mitotic regulation of MYO10 in controlling genome stability. We characterized a degron motif and phosphorylation residues in the degron that mediate β-TrCP1-dependent MYO10 degradation. The level of phosphorylated MYO10 protein transiently increases during mitosis, which is accompanied by a spatiotemporal cellular localization change first accumulating at the centrosome then at the midbody. Depletion of MYO10 or expression of MYO10 degron mutants, including those found in cancer patients, disrupts mitosis, increases genomic instability and inflammation, and promotes tumor growth; however, they also increase the sensitivity of cancer cells to Taxol. Our studies demonstrate a critical role of MYO10 in mitosis progression, through which it regulates genome stability, cancer growth, and cellular response to mitotic toxins.

Shikonin and cisplatin synergistically overcome cisplatin resistance of ovarian cancer by inducing ferroptosis via upregulation of HMOX1 to promote Fe2+ accumulation

BACKGROUND

Cisplatin-based chemotherapy often results in ovarian cancer (OC) chemical resistance and treatment failure. The combination of natural compounds with platinum-based agents is a new strategy for overcoming cisplatin resistance. At present, the synergistic effects and mechanism of combination of shikonin and cisplatin to overcome cisplatin resistance in OC are still unknown.

PURPOSE

This study was to evaluate the synergistic effects of shikonin and cisplatin on cisplatin-resistant OC cells and to assess the underlying molecular basis for these effects.

METHODS

Cell counting kit-8 assay, colony-formation assay, proteomic analysis, reactive oxygen species (ROS) detection, lipid peroxidation (LPO) detection, Fe²⁺ detection, western blot, and quantitative real-time reverse transcription PCR (qRT-PCR) were performed to evaluate the effects of shikonin and cisplatin on cisplatin-resistant OC cells. Underlying mechanisms of action were investigated in vitro using small molecule inhibitors and siRNA. In vivo, the effect of shikonin and cisplatin combination on tumor growth in BALB/c nude mice was evaluated, with tumor immunohistochemical (IHC) staining performed to detect ferroptosis-related proteins.

RESULTS

In vitro, shikonin and cisplatin were shown to synergistically reduce the viability of cisplatin-resistant OC cells. Proteomic results demonstrated that the combination of the two drugs induced a ferroptotic process, as evidenced by increased levels of ROS, LPO, and Fe²⁺, with downregulation of glutathione peroxidase 4 (GPX4). Heme oxygenase 1 (HMOX1) inhibition and siRNA interference attenuated the combined effect of the two drugs on cell viability. Accumulation of Fe²⁺ was attenuated by siRNA interference of HMOX1. In vivo, combination treatment significantly inhibited the growth of subcutaneous tumors in BALB/c nude mice and increased the expression of ferroptosis-related proteins in tumor tissue.

CONCLUSION

We report for the first time that the co-treatment of shikonin and cisplatin overcomes cisplatin resistance in OC through ferroptosis. Mechanistic analysis reveals the co-treatment induces ferroptosis through upregulation of HMOX1 that promotes Fe²⁺ accumulation.

A novel sorbicillinoid compound as a potent anti-inflammation agent through inducing NLRP3 protein degradation

BACKGROUND AND PURPOSE

Chronic inflammation is pathogenic and contributes to human diseases, causing a significant threat to public health. The NLR family pyrin domain-containing protein 3 (NLRP3) is the best-characterized factor regulating inflammation. Therefore, targeting NLRP3 has the potential to treat inflammatory diseases and improve human health.

EXPERIMENTAL APPROACH

Lipopolysaccharide was used to induce inflammation in cell cultures. Lipopolysaccharide/d-galactosamine and dextran sulfate sodium salt were used to induce acute liver inflammation and ulcerative colitis respectively in C57BL/6J mice. Western blotting, immunofluorescence, immunoprecipitation, quantitative PCR and enzyme-linked immunosorbent assay (ELISA) were used to evaluate the activation of the inflammatory response in cell cultures and in mice.

KEY RESULTS

JNUTS013, a novel sorbicillinoid compound recently synthesized by us, significantly inhibited inflammation both in cell cultures and in mouse models. Mechanistically, JNUTS013 induced proteasome-dependent degradation of NLRP3. Hence, it suppressed the formation of the NLRP3 inflammasome and the production of downstream inflammatory cytokines and chemokines. The inhibitory effect of JNUTS013 on NLRP3 protein expression was confirmed in mice. Importantly, JNUTS013 failed to ameliorate bowel inflammation in Nlrp3^-/- knockout mice, supporting NLRP3 as the biological target by which JNUTS013 inhibits inflammation. Further studies revealed critical chemical moieties of JNUTS013 required for inducing NLRP3 degradation.

CONCLUSION AND IMPLICATIONS

This study identifies a novel compound JNUTS013 that inhibits inflammation through inducing NLRP3 protein degradation in vitro and in vivo, which not only supports the development of JNUTS013 as an anti-inflammation agent but also creates a new way for the treatment of inflammation by chemically inducing NLRP3 degradation.

Vibsane-type diterpenoids from Viburnum odoratissimum inhibit hepatocellular carcinoma cells via the PI3K/AKT pathway

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, with an elevated danger of metastasis and a short survival rate. Vibsane-type diterpenoids with novel structures possess marked antitumor activities against multiple cancer cells. However, the exact mechanism is poorly unclear.

PURPOSE

To assess the antitumor mechanism of vibsane-type diterpenoids derived from Viburnum odoratissimum (V. odoratissimum) against HCC cells in vitro and in vivo.

METHODS

The main constituents in the ethyl acetate extract of V. odoratissimum (EAVO) were identified by LC-MS/MS. The antiproliferative activity of EAVO in vitro was evaluated by MTT assays. Annexin V-FITC/PI, AO/EB, and Hoechst 33,258 staining were employed to detect apoptosis. JC-1 fluorescence dye was used to detect the mitochondrial membrane potential (MMP). The levels of intracellular ROS and mitochondrial superoxides were assessed by H₂DCF-DA and MitoSox staining, respectively. The levels of oxidative stress were determined by ROS Green™ H₂O₂ probe, hydroxyphenyl fluorescein (HPF), and the C11 BODIPY 581/591 fluorescent probe. Transcriptomics was performed to investigate the antitumor mechanism of EAVO in HCC. The molecular mechanism by which EAVO suppressed HCC cells was verified by Western blot, RT-PCR, and HTRF® KinEASE™-STK S3 kits. The efficacy and safety of EAVO in vivo were evaluated using Hep3B xenograft models.

RESULTS

Vibsane-type diterpenoids were the main constituents of EAVO by LC-MS/MS. EAVO suppressed proliferation, aggravated oxidative stress, and promoted apoptosis in HCC cells. Moreover, EAVO dramatically inhibited tumor growth in Hep3B xenograft models. Transcriptomics results indicated that EAVO inhibited HCC cell proliferation by regulating the PI3K/AKT pathway. Vibsanin B, vibsanol I, and vibsanin S isolated from EAVO was used to further verify the antitumor activity of vibsane-type diterpenoids subsequently. Interestingly, the kinase results showed that vibsanin B and vibsanol I exhibited vital AKT kinase inhibitory activities.

CONCLUSIONS

Collectively, this study provided a comprehensive mechanism overview of vibsane-type diterpenoids against HCC cells in vitro and in vivo. It also laid a foundation for further antitumor investigation of vibsane-type diterpenoids in V. odoratissimum.

Synthesis and Biological Evaluation of Cardiac Glycosides for Cancer Therapy by Targeting the DNA Damage Response

Cardiac glycosides (CGs) are bioactive compounds originally used to treat heart diseases, but recent studies have demonstrated their anticancer activity. We previously demonstrated that Antiaris toxicaria 2 (AT2) possesses anticancer activity in KRAS mutated lung cancers via impinging on the DNA damage response (DDR) pathway. Toward developing this class of molecules for cancer therapy, herein we report a multistep synthetic route utilizing k-strophanthidin as the initial building block for determination of structure-activity relationships (SARs). A systematic structural design approach was applied that included modifications of the sugar moiety, the glycoside linker, stereochemistry, and lactone ring substitutions to generate a library of O-glycosides and MeON-neoglycosides derivatives. These molecules were screened for their anticancer activities and their impact on DDR signaling in KRAS mutant lung cancer cells. These results demonstrate the ability to chemically synthesize CG derivatives and define the SARs to optimize AT2 as a cancer therapeutic.

Naphthoquinones and triterpenoids from Arnebia euchroma (Royle) Johnst and their hypoglycemic and lipid-lowering effects

A new pentacyclic triterpenoid, 2-hydroxy-1-ene-hydroxyhopanone (19), and a new benzoxepin-5-one, 3-(4-methyl-3-penten-1-yl)-6-hydroxy-9-methoxy-2H-1-benzoxepin-5-one (25), along with 26 known compounds (1-18, 20-24, 26-28), were isolated from the roots of Arnebia euchroma (Royle) Johnst. The structures of the new compounds were elucidated by extensive spectroscopic analyses. The absolute configurations of shikonofurans 9-13 were determined by quantum chemical ECD calculations and CD spectra comparison for the first time. Pharmacological study revealed that naphthoquinones 1-5, 7, and 8 had obvious cytotoxicity toward human lung adenocarcinoma A549 cell line. Meanwhile, the hypoglycemic and lipid-lowering effects of isolated compounds were assessed by checking their inhibitory effects on key enzymes regulating glucose and lipid metabolism. Results showed that compounds 1, 3, 5, 6, 8, 18, and 19 could inhibit the activity of ATP-citrate lyase (ACL); compound 7 could inhibit the activity of acetyl-CoA carboxylase (ACC1); while compounds 8 and 19 showed inhibitory effects on protein tyrosine phosphatase 1B (PTP1B). Among them, the naphthoquinone 6, steroid 18, and triterpenoid 19 showed moderate inhibitory effects on ACL and PTP1B, but didn't exhibit obvious cytotoxicity. This study demonstrated that compounds 6, 18, and 19 show great promising for the development of new agents for the treatment of metabolic diseases.

53BP1 regulates heterochromatin through liquid phase separation

Human 53BP1 is primarily known as a key player in regulating DNA double strand break (DSB) repair choice; however, its involvement in other biological process is less well understood. Here, we report a previously uncharacterized function of 53BP1 at heterochromatin, where it undergoes liquid-liquid phase separation (LLPS) with the heterochromatin protein HP1α in a mutually dependent manner. Deletion of 53BP1 results in a reduction in heterochromatin centers and the de-repression of heterochromatic tandem repetitive DNA. We identify domains and residues of 53BP1 required for its LLPS, which overlap with, but are distinct from, those involved in DSB repair. Further, 53BP1 mutants deficient in DSB repair, but proficient in LLPS, rescue heterochromatin de-repression and protect cells from stress-induced DNA damage and senescence. Our study suggests that in addition to DSB repair modulation, 53BP1 contributes to the maintenance of heterochromatin integrity and genome stability through LLPS.