Lysosomal-targeted doxorubicin delivery using RBC-derived vesicles to overcome drug-resistant cancer through mitochondrial-dependent cell death.

Multidrug resistance (MDR) is a major challenge in cancer chemotherapy. Nanoparticles as drug delivery systems (DDSs) show promise for MDR cancer therapy. However, current DDSs require sophisticated design and construction based on xenogeneic nanomaterials, evoking feasibility and biocompatibility concerns. Herein, a simple but versatile biological DDS (bDDS) composed of human red blood cell (RBC)-derived vesicles (RDVs) with excellent biocompatibility was surface-linked with doxorubicin (Dox) using glutaraldehyde (glu) to form Dox-gluRDVs that remarkably suppressed MDR in uterine sarcoma through a lysosomal-mitochondrial axis-dependent cell death mechanism. Dox-gluRDVs can efficiently deliver and accumulate Dox in lysosomes, bypassing drug efflux transporters and facilitating cellular uptake and retention of Dox in drug-resistant MES-SA/Dx5 cells. The transfer of lysosomal calcium to the mitochondria during mitochondria-lysosome contact due to lysosomal Dox accumulation may result in mitochondrial ROS overproduction, mitochondrial membrane potential loss, and activation of apoptotic signaling for the superior anti-MDR activity of Dox-gluRDVs in vitro and in vivo. This work highlights the great promise of RDVs to serve as a bDDS of Dox to overcome MDR cancers but also opens up a reliable strategy for lysosomal-mitochondrial axis-dependent cell death for fighting against other inoperable cancers.

Synthesis and Structure-Activity Relationship of Salvinal Derivatives as Potent Microtubule Inhibitors.

Salvinal is a natural lignan isolated from the roots of Salvia mitorrhiza Bunge (Danshen). Previous studies have demonstrated its anti-proliferative activity in both drug-sensitive and -resistant cancer cell lines, with IC50 values ranging from 4-17 µM. In this study, a series of salvinal derivatives was synthesized and evaluated for the structure-activity relationship. Among the twenty-four salvinal derivatives, six compounds showed better anticancer activity than salvinal. Compound 25 displayed excellent anticancer activity, with IC50 values of 0.13-0.14 µM against KB, KB-Vin10 (overexpress MDR/Pgp), and KB-7D (overexpress MRP) human carcinoma cell lines. Based on our in vitro microtubule depolymerization assay, compound 25 showed depolymerization activity in a dose-dependent manner. Our findings indicate that compound 25 is a promising anticancer agent with depolymerization activity that has potential for the management of malignance.

Type-3 Hyaluronan Synthase Attenuates Tumor Cells Invasion in Human Mammary Parenchymal Tissues.

The microenvironment for tumor growth and developing metastasis should be essential. This study demonstrated that the hyaluronic acid synthase 3 (HAS3) protein and its enzymatic product hyaluronic acid (HA) encompassed in the subcutaneous extracellular matrix can attenuate the invasion of human breast tumor cells. Decreased HA levels in subcutaneous Has3-KO mouse tissues promoted orthotopic breast cancer (E0771) cell-derived allograft tumor growth. MDA-MB-231 cells premixed with higher concentration HA attenuate tumor growth in xenografted nude mice. Human patient-derived xenotransplantation (PDX) experiments found that HA selected the highly migratory breast cancer cells with CD44 expression accumulated in the tumor/stroma junction. In conclusion, HAS3 and HA were detected in the stroma breast tissues at a high level attenuates effects for induced breast cancer cell death, and inhibit the cancer cells invasion at the initial stage. However, the highly migratory cancer cells were resistant to the HA-mediated effects with unknown mechanisms.

MiR-30a and miR-379 modulate retinoic acid pathway by targeting DNA methyltransferase 3B in oral cancer.

BACKGROUND: Epigenetic silencing of retinoic acid (RA) signaling-related genes have been linked with the pathogenesis and clinical outcome in oral squamous cell carcinoma (OSCC) carcinogenesis. However, the precise mechanisms underlying the abnormal silencing of RA signaling-related genes in OSCC have not been well investigated. METHODS: Using combined analysis of genome-wide gene expression and methylation profile from 40 matched normal-tumor pairs of OSCC specimens, we found a set of retinoid signaling related genes are frequently hypermethylated and downregulated in OSCC patient samples, including alcohol dehydrogenase, iron containing 1 (ADHFE1) and aldehyde dehydrogenase 1 family, member A2 (ALDH1A2), which are the important rate-limiting enzymes in synthesis of RA. The expression of ADHFE1 and ALDH1A2 in OSCC patients was determine by quantitative real-time PCR (qRT-PCR) and immunohistochemistry. The binding sites of miR-30a and miR-379 with DNA methyltransferase 3B (DNMT3B) were predicted using a series of bioinformatic tools, and validated using dual luciferase assay and Western blot analyses. The functions of miR-30a, miR-379, and DNMT3B were accessed by growth and colony formation analyses using gain- and loss-of-function approaches. Chromatin immunoprecipitation (ChIP) was performed to explore the molecular mechanisms by arecoline and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) treatment. RESULTS: We demonstrated that deregulated miR-30a and miR-379 could represent a mechanism for the silencing of ADHFE1 and ALDH1A2 in OSCC through targeting DNMT3B. Ectopic expression of miR-30a and miR-379 could induce re-expression of methylation-silenced ADHFE1 and ALDH1A2, and lead to growth inhibition in oral cancer cells. Furthermore, the dysregulation of the miRNAs and DNMT-3B may result from exposure to tobacco smoking and betel quid chewing. CONCLUSIONS: Our results demonstrate that tobacco smoking and betel quid chewing could repress miR-30a and miR-379, which upregulate the DNMT3B expression, in turn, lead to the hypermethylation of ADHFE1 and ALDH1A genes, consequently, promote the oncogenic activity. These findings highlight the potential use of retinoids in combination with epigenetic modifiers for the prevention or treatment of oral cancer.

Novel microtubule inhibitor MPT0B098 inhibits hypoxia-induced epithelial-to-mesenchymal transition in head and neck squamous cell carcinoma.

BACKGROUND: Tumor hypoxia-induced epithelial-mesenchymal transition (EMT) is critical in promoting cancer metastasis. We recently discovered a novel microtubule inhibitor, MPT0B098, that employs a novel antitumor mechanism. It destabilizes hypoxia-inducible factor (HIF)-1α mRNA by blocking the function of human antigen R. Thus, we proposed that MPT0B098 modulates hypoxia-induced EMT. METHODS: In vitro IC50 values were determined through the methylene blue dye assay. To investigate molecular events, reverse transcriptase-polymerase chain reaction, Western blotting, immunofluorescence staining, and wound healing assay were employed. RESULTS: MPT0B098 significantly inhibited HIF-1α expression, epithelial-to-mesenchymal morphology changes, and migratory ability in the human head and neck squamous cell carcinoma cell line OEC-M1. Furthermore, after MPT0B098 treatment, the expression of two mesenchymal markers, vimentin and N-cadherin, was downregulated under hypoxic conditions. Moreover, MPT0B098 suppressed hypoxia-induced EMT in part by inhibiting EMT-activating transcription factors, Twist and SNAI2/Slug. In addition, the inhibition of hypoxia-induced F-actin rearrangement and focal adhesion kinase phosphorylation may have contributed to suppression of EMT by MPT0B098in OEC-M1 cells. MPT0B098 significantly inhibited transforming growth factor(TGF)-ß-induced phosphorylation of receptor-associated Smad2/3 by downregulating TGF-ß mRNA and protein expression. CONCLUSIONS: Taken together, this study provides a novel insight into the role of MPT0B098 in inhibiting hypoxia-induced EMT, suggesting its potential use for treating head and neck cancers.

Correction: 2-Aroylquinoline-5,8-diones as potent anticancer agents displaying tubulin and heat shock protein 90 (HSP90) inhibition.

Correction for '2-Aroylquinoline-5,8-diones as potent anticancer agents displaying tubulin and heat shock protein 90 (HSP90) inhibition' by Kunal Nepali et al., Org. Biomol. Chem., 2016, 14, 716-723.

4-Bromophenylhydrazinyl benzenesulfonylphenylureas as indoleamine 2,3-dioxygenase inhibitors with in vivo target inhibition and anti-tumor efficacy.

Indoleamine 2,3-dioxygenase is a heme-containing enzyme implicated in the down regulation of the anti-tumor immune response, and considered a promising anti-cancer drug target. Several pharmaceutical companies, including Pfizer, Merck, and Bristol-Myers Squibb, are known to be in pursuit of IDO inhibitors, and Incyte recently reported good results in the phase II clinical trial of the IDO inhibitor Epacadostat. In previous work, we developed a series of IDO inhibitors based on a sulfonylhydrazide core structure, and explored how they could serve as potent IDO inhibitors with good drug profiles. Herein, we disclose the development of the 4-bromophenylhydrazinyl benzenesulfonylphenylurea 5k, a potent IDO inhibitor which demonstrated 25% tumor growth inhibition in a murine CT26 syngeneic model on day 18 with 100 mg/kg oral administration twice daily, and a 30% reduction in tumor weight. Pharmacodynamic testing of 5k found it to cause a 25% and 21% reduction in kyn/trp ratio at the plasma and tumor, respectively. In the CT26 tumor model, 5k was found to slightly increase the percentage of CD3+ T cells and lymphocyte responsiveness, indicating that 5k may have potential in modulating anti-tumor immunity. These data suggest 5k to be worthy of further investigation in the development of anti-tumor drugs.

2-Aroylquinoline-5,8-diones as potent anticancer agents displaying tubulin and heat shock protein 90 (HSP90) inhibition.

This study reports the synthesis of a series of 2-aroylquinoline-5,8-diones (11-23) on the basis of scaffold hopping. The presence of a methoxy group at C6 assists the highly regioselective incorporation with various amines, and simplifies the structural identification process. Among the synthetic compounds, 6-dimethylamino-2-(3,4,5-trimethoxybenzoyl)-quinoline-5,8-dione (12) and 7-pyrrolidin-1-yl-2-(3,4,5-trimethoxybenzoyl)-quinoline-5,8-dione (23) exhibit remarkable anti-proliferative activity against the cancer cell lines tested with mean IC50 values of 0.14 and 0.27 µM, respectively. Compound 23 showed moderate inhibitory activity against tubulin polymerization with an IC50 value of 5.9 µM. In a western blot analysis, 23 caused induction of HSP70 and degradation of Akt, revealing that it possesses HSP90 inhibitory activity.

O(6) -methylguanine DNA methyltransferase repairs platinum-DNA adducts following cisplatin treatment and predicts prognoses of nasopharyngeal carcinoma.

Cisplatin (CDDP) is an important anti-cancer drug commonly used in various human cancers, including nasopharyngeal carcinoma (NPC). How to overcome the drug resistance of CDDP provides opportunities to improve clinical outcomes of NPC. O(6) -methylguanine-DNA methyltransferase (MGMT) has been well-characterized to be a therapeutic determinant of O(6) -alkylguanine alkylating drugs. However, the underlying mechanism and clinical relevance between MGMT and CDDP remain poorly defined in NPC. In this study, we showed that MGMT-proficient cells were highly resistant to the cytotoxic effects of CDDP as compared to MGMT-deficient cells. Further studies showed that the platinum level of DNA after CDDP exposure was significantly lower in MGMT-proficient cells than in MGMT-deficient cells. Host cell reactivation assay revealed that MGMT protected NPC cells from CDDP-induced DNA damage by enhancing DNA repair capacity. Importantly, we demonstrated for the first time that MGMT protein directly bound to CDDP-induced DNA damages. Subsequently, CDDP-bound MGMT protein became ubiquitinated and was degraded through ubiquitin-mediated proteasome system. We further analyzed the relationship between MGMT expression and clinical survivals in a cohort of 83 NPC patients. NPC patients who received CDDP-based concurrent chemoradiotherapy (CCRT), with high MGMT expression level, exhibited shorter progression-free survival (PFS; p = 0.022) and overall survival (OS; p = 0.015), than patients with low MGMT expression level. Furthermore, high MGMT expression level remained to be an independent prognostic factor for worse PFS (p = 0.01, hazard ratio 2.23) and OS (p = 0.018, hazard ratio 2.14). Our findings suggest that MGMT protein is important to determine the efficacy of CDDP in NPC.

Novel Nrf2/ARE activator, trans-Coniferylaldehyde, induces a HO-1-mediated defense mechanism through a dual p38α/MAPKAPK-2 and PK-N3 signaling pathway.

The induction of detoxifying enzymes and antioxidant proteins by chemopreventive agents protects cells from oxidizing substances capable of damaging DNA integrity and initiating carcinogenesis. Coniferyl aldehyde, a naturally occurring substance, has been found in many foods and edible plants. We and others previously demonstrated that trans-coniferylaldehyde (t-CA) has potential antimutagenic and antioxidant properties. However, the mechanism underlying its Nrf2-mediated antioxidant effect remains largely unknown. In the present study, we demonstrated that t-CA significantly stimulated antioxidant-responsive element (ARE)-driven luciferase activity in a cell model and increased the expression of ARE-dependent detoxifying/antioxidant genes and their protein products in vitro and in vivo. The detoxifying/antioxidant genes activated by t-CA, especially heme oxygenase-1 (HO-1), were found to be involved in its cytoprotective effects against oxidative stress and cell injuries elicited by carcinogens tert-butylhydroperoxide and arecoline. Furthermore, the t-CA-induced phosphorylation and nuclear translocation of nuclear factor erythroid-2-related factor 2 (Nrf2) played a crucial role in this ARE-mediated cellular defense. Moreover, we found that p38 MAPK and protein kinase C (PKC) signaling pathways participated in the t-CA-induced, Nrf2-mediated cytoprotective effect. Among them, p38α/MAPKAPK-2 and an atypical PKC, PK-N3, were critical for the activation of the Nrf2/HO-1 axis by t-CA. In conclusion, we demonstrated for the first time that t-CA attenuates carcinogen-induced oxidative stress by activating Nrf2 via p38α/MAPKAPK-2- and PK-N3-dependent signaling pathways. In addition, t-CA increased the level of Nrf2-mediated detoxifying/antioxidant proteins in vivo, suggesting that t-CA may have potential for use in the management of carcinogenesis and meriting further investigation.

Antimitotic and antivascular activity of heteroaroyl-2-hydroxy-3,4,5-trimethoxybenzenes.

This study reports the synthesis of a series of heteroaroyl-2-hydroxy-3,4,5-trimethoxybenzenes, which are potent antitubulin agents. Compound 13, (2-hydroxy-3,4,5-trimethoxyphenyl)-(6-methoxy-1H-indol-3-yl)-methanone exhibits marked antiproliferative activity against KB and MKN45 cells with IC50 values of 8.8 and 10.5 nM, respectively, binds strongly to the colchicine binding site and leads to inhibition of tubulin polymerization. It also behaves as a vascular disrupting agent which suppresses the formation of capillaries. The C2-OH group in the A-ring of this compound not only retains the biological activity but has valuable physicochemical properties.

Concise syntheses of 7-anilino-indoline-N-benzenesulfonamides as antimitotic and vascular disrupting agents.

Described herein is the development of a novel series of 7-anilino-indoline-N-benzenesulfonamides, derived from ABT751 (1), as potent anticancer agents. Amongst the synthesized series, compounds 6, 12, 13, and 14 have shown comparable to better anticancer activity on comparing with compound 1. 7-(4-Cyanophenylamino)-1-(4-methoxybenzenesulfonyl)indoline (13) was found to be the most potent one with up to 6 fold better activity against KB, HT29, and MKN45 cancer cell lines with IC50 values of 49.7, 149, and 92nM, respectively. Compound 13 was also found inhibiting multidrug resistant cancer cell lines, blocking cell cycle at G2/M phase, and inhibiting tubulin polymerization. Capillary disruption assay results revealed that compound 13 was able to disrupt formed capillaries in a concentration-dependent manner without affecting cell viability.

Heart failure and angiotensin II modulate atrial Pitx2c promotor methylation.

Heart failure (HF) can increase atrial fibrillation and induce cardiac hypermethylation. The homeobox gene Pitx2c plays important roles in the genesis of atrial fibrillation and the promoter region of Pitx2c contains cytosine-phosphate-guanine islands. Therefore, epigenetic modification by hypermethylation may reduce Pitx2c expression in atrial myocytes. The aim of the present study were to evaluate whether HF can modulate DNA methylation of Pitx2c and the potential mechanisms involved. We used real-time polymerase chain reaction, immunoblotting and pyrosequencing to investigate RNA and protein expression, as well as the methylation of Pitx2c, in isoproterenol-induced HF, healthy rat left atria and in HL-1 cells with and without (control) exposure to angiotensin (Ang) II (0.1 and 1 µmol/L) or isoproterenol (1 or 10 µmol/L) for 24 h. The HF atrium exhibited increased Pitx2c promoter methylation with increased DNA methyltransferase (DNMT) 1 and decreased Pitx2c protein levels compared with the normal atrium. Angiotensin II (0.1 and 1 µmol/L), increased Pitx2c promoter methylation in HL-1 cells with increased DNMT1 and decreased Pitx2c and Kir2.1 protein levels compared with control cells. These effects were attenuated by the methylation inhibitor 5-aza-2'-deoxycytidine (0.1 µmol/L) and by the AngII receptor blocker losartan (10 µmol/L). However, isoproterenol (1 and 10 µmol/L) did not change the expression of the Pitx2c, DNMT1 and Kir2.1 proteins. In conclusion, HF induces Pitx2c promoter hypermethylation and AngII may contribute to the hypermethylation in HF.

Two new chromones and a new coumarin from the fruit of Cnidium monnieri (L.) Cusson.

Two new chromones named cnidimol G (1) and cnidimol H (2), one new coumarin, 7-methoxy-8-(3-methoxy-3-methyl-2-oxobutyl)coumarin (3), and twenty known compounds were isolated from MeOH extract of the fruit of Cnidium monnieri (L.) Cusson. The structures of compounds were elucidated by extensive spectroscopic analyses including 1 D and 2 D NMR, HRESIMS, IR and UV. Anti-inflammatory activity of the selected isolated compounds were evaluated. Compounds 1 and 8 exhibited inhibitory activities against nitric oxide production.

Application of Suzuki arylation, Sonogashira ethynylation and Rosenmund-von Braun cyanation in the exploration of substitution effects on the anticancer activity of 2-aroylquinolines.

A variety of functionalities were introduced at 2-aroylquinoline's C5 position, which is considered equivalent to C-3' of the B-ring of CA4, via Suzuki arylation, Sonogashira ethynylation, and Rosenmund-von Braun cyanation. These substitutions are rarely utilized in the modification of 3'-OH of CA4. The resulting products 6 and 7 having cyano and ethynyl groups exhibited comparable antiproliferative and tubulin inhibitory activities to colchicine.

Discovery and development of a novel N-(3-bromophenyl)-{[(phenylcarbamoyl)amino]methyl}-N-hydroxythiophene-2-carboximidamide indoleamine 2,3-dioxygenase inhibitor using knowledge-based drug design.

Indoleamine 2,3-dioxygenase-1 (IDO1) is a potential target for the next generation of cancer immunotherapies. We describe the development of two series of IDO1 inhibitors incorporating a N-hydroxy-thiophene-carboximidamide core generated by knowledge-based drug design. Structural modifications to improve the cellular activity and pharmacokinetic (PK) properties of the compounds synthesized, including extension of the side chain of the N-hydroxythiophene-2-carboximidamide core, resulted in compound 27a, a potent IDO1 inhibitor which demonstrated significant (51%) in vivo target inhibition on IDO1 in a human SK-OV-3 ovarian xenograft tumor mouse model. This strategy is expected to be applicable to the discovery of additional IDO1 inhibitors for the treatment of other diseases susceptible to modulation of IDO1.

Concise syntheses of N-aryl-5,6,7-trimethoxyindoles as antimitotic and vascular disrupting agents: application of the copper-mediated Ullmann-type arylation.

In an attempt to mimic the 3,4,5-trimethoxyphenyl-Z-stilbene moiety of combretastatin A-4, a series of N-aryl-5,6,7-trimethoxyindoles were synthesized via copper-catalyzed Ullmann-type N-arylation through the corresponding 5,6,7-trimethoxyindole and aryl halides. These synthesized compounds demonstrated potent antiproliferative activity providing a novel skeleton for potent tubulin polymerization inhibitors.

Cytotoxic steroidal saponins from Agave sisalana.

Two new steroidal saponins, 8 and 10, along with 7 known steroidal sapogenins and saponins (1-7) and a furostanol saponin (9) were isolated from Agave sisalana Perrine ex Engelm. The structures of these two new compounds were identified and characterized by 1D and 2D NMR spectroscopy and mass spectrometry. In addition, acid hydrolysis and GC-FID were used to confirm the sugar moieties of 8 and 10. The cytotoxic effects of 1-10 on MCF-7, NCI-H460, and SF-268 cancer cells were evaluated, and among them, compound 10 proved to be the most cytotoxic with IC50 values of 1.2, 3.8, and 1.5 µM, respectively.

Novel terpenoids from Calocedrus macrolepis var. formosana.

Calocetriol (1), diacetylcalocediol (2), and ferrugimenthenol (3) were isolated from the bark of Calocedrus macrolepis var. formosana. Among them, 1 and 2 are secoabietane-type diterpenoids, and 3, with a novel C(20)-C(10) skeleton, is classified as a meroterpenoid. The structures of 1-3 were elucidated by spectroscopic analyses, and their biological activities were also evaluated. Compound 3 exhibited significant cytotoxic activity against human oral epidermoid carcinoma KB cells with an IC(50) value of 9.0±0.1 µM.

Synthesis and biological evaluation of 4-aroyl-6,7,8-trimethoxyquinolines as a novel class of anticancer agents.

A series of 2-aroyl and 2-aryl-5,6,7-trimethoxyquinoline and 4-aroyl-6,7,8-trimethoxyquinoline combretastatin analogs were synthesized and evaluated for their potential anticancer activity. The 4-aroylquinoline 11 inhibited the growth of the human cancer cells lines KB, HT-29, and MKN45, as well as the three human resistant cancer cell lines KB-vin10, KB-S15, and KB-7D, with IC50 values of 217, 327, 239, 246, 213, and 252 nM, respectively.