Syntheses of LSD1/HDAC Inhibitors with Demonstrated Efficacy against Colorectal Cancer: In Vitro and In Vivo Studies Including Patient-Derived Organoids.

Precedential evidence ascertaining the overexpression of LSD1 and HDACs in colorectal cancer spurred us to design a series of dual LSD1-HDAC inhibitors. Capitalizing on the modular nature of the three-component HDAC inhibitory model, tranylcypromine as a surface recognition motif was appended to zinc-binding motifs via diverse linkers. A compendium of hydroxamic acids was generated and evaluated for in vitro cytotoxicity against HCT-116 cells (human colorectal cancer cell lines). The most potent cell growth inhibitor 2 (GI50 = 0.495 µMm HCT-116 cells) shows promising anticancer effects by reducing colony formation and inducing cell cycle arrest in HCT-116 cells. It exhibits preferential inhibition of HDAC6, along with potent inhibition of LSD1 compared to standard inhibitors. Moreover, Compound 2 upregulates acetyl-tubulin, acetyl-histone H3, and H3K4me2, indicative of LSD1 and HDAC inhibition. In vivo, it demonstrates significant antitumor activity against colorectal cancer, better than irinotecan, and effectively inhibits growth in patient-derived CRC organoids.

Targeted metabolomics assisted rapid screening and characterization of aristolochic acids and their DNA adducts in aristolochia plants by ultra-high performance liquid chromatography coupled with ion mobility quadrupole time-of-flight mass spectrometry.

Aristolochic acids are one of the major compounds in aristolochia plants, which are nephrotoxic and carcinogenic. A method was established for the detection and identification of aristolochic acids and their DNA adducts in four different herbs using ultra-high performance liquid chromatography-ion mobility quadrupole time-of flight mass spectrometry. Solid phase extraction conditions were optimized to improve the sensitivity of the experiment by using 40 mg of C18 as adsorbent and 100 µL ethanol as elution solvent. At a collision energy of 10-40 eV, these compounds and cleavage patterns were precisely identified and analyzed by secondary fragmentation and collision cross section values. The obtained mass spectrometry data were then analyzed by targeted metabolomics, including principal component analysis, partial least squares-discriminant analysis and hierarchical clustering analysis, and importing the samples in the established model, the confidence values can reach 0.61 and 0.76. All in all, this method can provide a useful tool for the detection of aristolochic acids and deoxyribonucleic acid adducts. In conclusion, this method was successfully used for the detection and identification of aristolochic acids and their DNA adducts.

Synthesis and evaluation of potent (iso)ellipticine-based inhibitors of MYLK4 accessed via expeditious synthesis from isoquinolin-5-ol.

The K2S2O8-mediated generation of p-iminoquinone contributed to the regioselective substitution of isoquinolin-5,8-dione. This hydroxyl group-guided substitution was also applied to selected heterocycles and addressed the regioselectivity issue of quinones. This study has provided an expeditious pathway from isoquinolin-5-ol (5) to ellipticine (1) and isoellipticine (2), which benefits the comprehensive comparison of their activity. Compounds 1 and 2 displayed marked MYLK4 inhibitory activity with IC50 values of 7.1 and 6.1 nM, respectively. In the cellular activity of AML cells (MV-4-11 and MOLM-13), compound 1 showed better AML activity than compound 2.

Three-dimensional ultrasound-based radiomics nomogram for the prediction of extrathyroidal extension features in papillary thyroid cancer.

Purpose: To develop and validate a three-dimensional ultrasound (3D US) radiomics nomogram for the preoperative prediction of extrathyroidal extension (ETE) in papillary thyroid cancer (PTC). Methods: This retrospective study included 168 patients with surgically proven PTC (non-ETE, n = 90; ETE, n = 78) who were divided into training (n = 117) and validation (n = 51) cohorts by a random stratified sampling strategy. The regions of interest (ROIs) were obtained manually from 3D US images. A larger number of radiomic features were automatically extracted. Finally, a nomogram was built, incorporating the radiomics scores and selected clinical predictors. Receiver operating characteristic (ROC) curves were performed to validate the capability of the nomogram on both the training and validation sets. The nomogram models were compared with conventional US models. The DeLong test was adopted to compare different ROC curves. Results: The area under the receiver operating characteristic curve (AUC) of the radiologist was 0.67 [95% confidence interval (CI), 0.580-0.757] in the training cohort and 0.62 (95% CI, 0.467-0.746) in the validation cohort. Sixteen features from 3D US images were used to build the radiomics signature. The radiomics nomogram, which incorporated the radiomics signature, tumor location, and tumor size showed good calibration and discrimination in the training cohort (AUC, 0.810; 95% CI, 0.727-0.876) and the validation cohort (AUC, 0.798; 95% CI, 0.662-0.897). The result suggested that the diagnostic efficiency of the 3D US-based radiomics nomogram was better than that of the radiologist and it had a favorable discriminate performance with a higher AUC (DeLong test: p < 0.05). Conclusions: The 3D US-based radiomics signature nomogram, a noninvasive preoperative prediction method that incorporates tumor location and tumor size, presented more advantages over radiologist-reported ETE statuses for PTC.

Development and Validation of a Radiomics Model Based on 3-Dimensional Endoanal Rectal Ultrasound of Rectal Cancer for Predicting Lymph Node Metastasis.

BACKGROUND: Development of a radiomics model for predicting lymph node metastasis status in rectal cancer patients based on 3-dimensional endoanal rectal ultrasound images. METHODS: This study retrospectively included 79 patients (41 with lymph node metastasis positive and 38 with lymph node metastasis negative) diagnosed with rectal cancer in our hospital from January 2018 to February 2022. The tumor's region of interest is first delineated by radiologists, from which radiomics features are extracted. Radiomics features were then selected by independent samples t-test, correlation coefficient analysis between features, and least absolute shrinkage and regression with selection operator. Finally, a multilayer neural network model is developed using the selected radiomics features, and nested cross-validation is performed on it. These models were validated by assessing their diagnostic performance and comparing the areas under the curve and recall rate curve in the test set. RESULTS: The areas under the curve of radiologist was 0.662 and the F1 score was 0.632. Thirty-four radiomics features were significantly associated with lymph node metastasis (P < .05), and 10 features were finally selected for developing multilayer neural network models. The areas under the curve of the multilayer neural network models were 0.787, 0.761, 0.853, and the mean areas under the curve was 0.800. The F1 scores of the multilayer neural network models were 0.738, 0.740, and 0.818, and the mean F1 score was 0.771. CONCLUSIONS: Radiomics models based on 3-dimensional endoanal rectal ultrasound can be used to identify lymph node metastasis status in rectal cancer patient with good diagnostic performance.

Development of Furanopyrimidine-Based Orally Active Third-Generation EGFR Inhibitors for the Treatment of Non-Small Cell Lung Cancer.

The development of orally bioavailable, furanopyrimidine-based double-mutant (L858R/T790M) EGFR inhibitors is described. First, selectivity for mutant EGFR was accomplished by replacing the (S)-2-phenylglycinol moiety of 12 with either an ethanol or an alkyl substituent. Then, the cellular potency and physicochemical properties were optimized through insights from molecular modeling studies by implanting various solubilizing groups in phenyl rings A and B. Optimized lead 52 shows 8-fold selective inhibition of H1975 (EGFRL858R/T790M overexpressing) cancer cells over A431 (EGFRWT overexpressing) cancer cells; western blot analysis further confirmed EGFR mutant-selective target modulation inside the cancer cells by 52. Notably, 52 displayed in vivo antitumor effects in two different mouse xenograft models (BaF3 transfected with mutant EGFR and H1975 tumors) with TGI = 74.9 and 97.5% after oral administration (F = 27%), respectively. With an extraordinary kinome selectivity (S(10) score of 0.017), 52 undergoes detailed preclinical development.

O-methylated flavonol as a multi-kinase inhibitor of leukemogenic kinases exhibits a potential treatment for acute myeloid leukemia.

BACKGROUND: Acute myeloid leukemia (AML) is a heterogeneous disease with poor overall survival characterized by various genetic changes. The continuous activation of oncogenic pathways leads to the development of drug resistance and limits current therapeutic efficacy. Therefore, a multi-targeting inhibitor may overcome drug resistance observed in AML treatment. Recently, groups of flavonoids, such as flavones and flavonols, have been shown to inhibit a variety of kinase activities, which provides potential opportunities for further anticancer applications. PURPOSE: In this study, we evaluated the anticancer effects of flavonoid compounds collected from our in-house library and investigated their potential anticancer mechanisms by targeting multiple kinases for inhibition in AML cells. METHODS: The cytotoxic effect of the compounds was detected by cell viability assays. The kinase inhibitory activity of the selected compound was detected by kinase-based and cell-based assays. The binding conformation and interactions were investigated by molecular docking analysis. Flow cytometry was used to evaluate the cell cycle distribution and cell apoptosis. The protein and gene expression were estimated by western blotting and qPCR, respectively. RESULTS: In this study, an O-methylated flavonol (compound 11) was found to possess remarkable cytotoxic activity against AML cells compared to treatment in other cancer cell lines. The compound was demonstrated to act against multiple kinases, which play critical roles in survival signaling in AML, including FLT3, MNK2, RSK, DYRK2 and JAK2 with IC50 values of 1 - 2 µM. Compared to our previous flavonoid compounds, which only showed inhibitions against MNKs or FLT3, compound 11 exhibited multiple kinase inhibitory abilities. Moreover, compound 11 showed effectiveness in inhibiting internal tandem duplications of FLT3 (FLT3-ITDs), which accounts for 25% of AML cases. The interactions between compound 11 and targeted kinases were investigated by molecular docking analysis. Mechanically, compound 11 caused dose-dependent accumulation of leukemic cells at the G0/G1 phase and followed by the cells undergoing apoptosis. CONCLUSION: O-methylated flavonol, compound 11, can target multiple kinases, which may provide potential opportunities for the development of novel therapeutics for drug-resistant AMLs. This work provides a good starting point for further compound optimization.

Ring-opening of five-membered heterocycles conjugated 4-isopropylresorcinol scaffold-based benzamides as HSP90 inhibitors suppressing tumor growth in vitro and in vivo.

A series of ring-opened dihydroxybenzamides have been designed and synthesized as heat shock protein 90 inhibitors. One of derivatives, compound 6b ((N-ethyl-2,4-dihydroxy-5-isopropyl-N-(pyridin-3-yl)benzamide)) demonstrated remarkable antiproliferative activity against in human KRAS mutant A549 and EGFR T790 M mutant H1975 lung cancer cell lines with GI50 values of 0.07 and 0.05 µM, respectively. It is also active against in other cancer cell lines, such as colorectal HCT116 (GI50 = 0.09 µM), liver Hep3B (GI50 = 0.20 µM) and breast MDA-MB-231 (GI50 = 0.09 µM), and shows no evidence of toxicity in normal cell line. Compound 6b has an IC50 of 110.18 nM in HSP90α inhibitory activity, slightly better than reference compound 1 (17-AAG, IC50 = 141.62 nM) and achieves the degradation of multiple HSP90 client proteins in a dose- and time-dependent manner and downstream signaling of Akt in a concentration- and time-dependent manner in the human A549 lung cancer cell line. In the Boyden chamber assay, compound 6b can efficiently inhibit the migration of A549 cells when compared to the reference compound 1. It also induce significant activity through the apoptotic pathway. Treatment with 6b showed no vision toxicity (IC50 > 10 µM) on 661w photoreceptor cells as compared to AUY922 (3a) with a 0.04 µM values of IC50 and has no effect in hERG test. In a bidirectional Caco-2 permeability assay, compound 6b was classified as a highly permeable compound which is not a substrate of efflux transporters. In a pharmacokinetic study in rats, 6b showed an F = 17.8% of oral bioavailability. The effect of metabolic stability of compound 6b in human hepatocytes showed a T1/2 of 67.59 min. Compound 6b (50 mg/kg, po, daily) exhibits antitumor activity with a 72% TGD (tumor growth delay) in human A549 lung xenograft. The combination of 6b and afatinib, orally administered, showed tumor growth suppression with 67.5% of TGI in lung H1975 xenograft model. Thus compound 6b is a lead compound for further development of potential agents to treat lung cancer.

A novel dual HDAC and HSP90 inhibitor, MPT0G449, downregulates oncogenic pathways in human acute leukemia in vitro and in vivo.

Acute leukemia is a highly heterogeneous disease; therefore, combination therapy is commonly used for patient treatment. Drug-drug interaction is a major concern of combined therapy; hence, dual/multi-target inhibitors have become a dominant approach for cancer drug development. HDACs and HSP90 are involved in the activation of various oncogenic signaling pathways, including PI3K/AKT/mTOR, JAK/STAT, and RAF/MEK/ERK, which are also highly enriched in acute leukemia gene expression profiles. Therefore, we suggest that dual HDAC and HSP90 inhibitors could represent a novel therapeutic approach for acute leukemia. MPT0G449 is a dual effect inhibitor, and it showed cytotoxic effectiveness in acute leukemia cells. Molecular docking analysis indicated that MPT0G449 possessed dual HDAC and HSP90 inhibitory abilities. Furthermore, MPT0G449 induced G2 arrest and caspase-mediated cell apoptosis in acute leukemia cells. The oncogenic signaling molecules AKT, mTOR, STAT3, STAT5, MEK, and ERK were significantly downregulated after MPT0G449 treatment in HL-60 and MOLT-4 cells. In vivo xenograft models confirmed the antitumor activity and showed the upregulation of acetyl-histone H3 and HSP70, biomarkers of pan-HDAC and HSP90 inhibition, with MPT0G449 treatment. These findings suggest that the dual inhibition of HDAC and HSP90 can suppress the expression of oncogenic pathways in acute leukemia, and MPT0G449 represents a novel therapeutic for anticancer treatment.

Association of early failure of arteriovenous fistula with mortality in hemodialysis patients.

Arteriovenous fistula (AVF) is prone to early dysfunction and relates to poor outcome. However, little is known about the role of early AVF dysfunction as an independent risk factor for death in hemodialysis patients. A retrospective cohort study was performed using data of patients who underwent initial AVF surgery at a single institution. Demographic, clinical, biochemistry and AVF parameters were extracted from the electronic records, and the association between these variables and mortality was analyzed by Cox proportional hazards model. A total of 501 patients on hemodialysis (63.4 ± 12.7 years, 57.3% male) were included, and the median observation period was 3.66 years. In multivariate analysis, early failure of AVF (hazard ratio (95% confidence interval): 1.54 (1.06-2.24); p = 0.023) was associated with overall mortality but not cardiovascular mortality. Other identified predictors of overall mortality included older age, peripheral artery disease (PAD), cardiomegaly, higher white blood cell (WBC) count and corrected calcium level, and lower total cholesterol level, while predictors of cardiovascular mortality included older age, coronary artery disease (CAD), PAD and lower hemoglobin level. In conclusion, patients with early AVF failure were associated with increased risk of overall mortality.

Investigation of Selected Flavonoid Derivatives as Potent FLT3 Inhibitors for the Potential Treatment of Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is an aggressive disease with a poor prognosis and a high degree of relapse seen in patients. Overexpression of FMS-like tyrosine kinase 3 (FLT3) is associated with up to 70% of AML patients. Wild-type FLT3 induces proliferation and inhibits apoptosis in AML cells, while uncontrolled proliferation of FLT3 kinase activity is also associated with FLT3 mutations. Therefore, inhibiting FLT3 activity is a promising AML therapy. Flavonoids are a group of phytochemicals that can target protein kinases, suggesting their potential antitumor activities. In this study, several plant-derived flavonoids have been identified with FLT3 inhibitory activity. Among these compounds, compound 40 (5,7,4'-trihydroxy-6-methoxyflavone) exhibited the most potent inhibition against not only FLT3 (IC50 = 0.44 µM) but also FLT3-D835Y and FLT3-ITD mutants (IC50 = 0.23 and 0.39 µM, respectively). The critical interactions between the FLT3 binding site and the compounds were identified by performing a structure-activity relationship analysis. Furthermore, the results of cellular assays revealed that compounds 28, 31, 32, and 40 exhibited significant cytotoxicity against two human AML cell lines (MOLM-13 and MV-4-11), and compounds 31, 32, and 40 resulted in cell apoptosis and G0/G1 cell cycle arrest. Collectively, these flavonoids have the potential to be further optimized as FLT3 inhibitors and provide valuable chemical information for the development of new AML drugs.

Biological Evaluation of Selected Flavonoids as Inhibitors of MNKs Targeting Acute Myeloid Leukemia.

Excessive eIF4E phosphorylation by mitogen-activated protein kinase (MAPK)-interacting kinases 1 and 2 (MNK1 and MNK2; collectively, MNKs) has been associated with oncogenesis. The overexpression of eIF4E in acute myeloid leukemia (AML) is related to cancer cell growth and survival. Thus, the inhibition of MNKs and eIF4E phosphorylation are potential therapeutic strategies for AML. Herein, a structure-based virtual screening approach was performed to identify potential MNK inhibitors from natural products. Three flavonoids, apigenin, hispidulin, and luteolin, showed MNK2 inhibitory activity with IC50 values of 308, 252, and 579 nM, respectively. A structure-activity relationship analysis was performed to disclose the molecular interactions. Furthermore, luteolin exhibited substantial inhibitory efficacy against MNK1 (IC50 = 179 nM). Experimental results from cellular assays showed that hispidulin and luteolin inhibited the growth of MOLM-13 and MV4-11 AML cells by downregulating eIF4E phosphorylation and arresting the cell cycle at the G0/G1 phase. Therefore, hispidulin and luteolin showed promising results as lead compounds for the potential treatment for AML.

N-alkyl-hydroxybenzoyl anilide hydroxamates as dual inhibitors of HDAC and HSP90, downregulating IFN-γ induced PD-L1 expression.

Novel dual inhibitors of histone deacetylase (HDAC) and heat-shock protein 90 (HSP90) are synthesized and evaluated. These compounds are endowed with potent HDAC and HSP90 inhibitory activities with IC50 values in nanomolar range with Compound 20 (HDAC IC50 = 194 nM; HSP90α IC50 = 153 nM) and compound 26 (HDAC IC50 = 360 nM; HSP90α IC50 = 77 nM) displaying most potent HDAC and HSP90α inhibitory activities. Both of these compounds induce HSP70 expression and down regulate HSP90 client proteins which play important roles in the regulation of survival and invasiveness in cancer cells. In addition, compounds 20 and 26 induce acetylation of α-tubulin and histone H3. Significantly, compounds 20 and 26 could effectively reduce programmed death-ligand 1 (PD-L1) expression in IFN-γ treated lung H1975 cells in a dose dependent manner. These findings suggest that dual inhibition of HDAC and HSP90 that can modulate immunosuppressive ability of tumor area may provide a better therapeutic strategy for cancer treatment in the future.

Assessment of the intramolecular magnetic interactions in the highly saddled iron(iii) porphyrin π-radical cations: the change from planar to saddle conformations.

The intramolecular magnetic interactions in one-electron oxidized iron(iii) porphyrin π-radical cations, [Fe(OETPP˙)Cl][SbCl6] (1), [Fe(OMTPP˙)Cl][SbCl6] (2) and [Fe(TPP˙)Cl][SbCl6] (3), have been compared by means of X-ray crystallography, SQUID magnetometry, cyclic voltammetry, UV-Vis spectroelectrochemical analysis, NMR spectroscopy analysis and unrestricted DFT calculations. Unlike a generally recognized antiferromagnetic coupling dxy↑dxz↑dyz↑dz2↑dx2-y2↑P˙+(a2u)↓ (S = 2) state via a weak bonding interaction as in (3), we have disclosed that a strong bonding interaction among iron dx2-y2 and porphyrin a2u orbitals forms in (1) into a highly delocalized Ψπ = [P˙+(a2u) + FeIII(dx2-y2, dz2)] orbital that is able to accommodate two spin-paired electrons to form the Ψπ2dxy1dxz1dyz1, dz21 (S = 2) ground state. Concurrently, the spin polarization effect is exerted on the paired spins in the Ψπ orbital by magnetic induction from the remaining unpaired electrons in the iron d orbitals. The interpretation mentioned above is further verified by the diamagnetic nature of the saddled copper(ii) porphyrin π-cation radical, CuII(OETPP˙)(ClO4) (S = 0), where the strong bonding interaction leads to the Ψπ2dxy2dxz2dyz2dz22 (S = 0) ground state but no spin polarization exists. Thus, the magnetic nature of the iron(iii) porphyrin π-radical cation is tuneable by saddling the ring planarity.

MPT0G413, A Novel HDAC6-Selective Inhibitor, and Bortezomib Synergistically Exert Anti-tumor Activity in Multiple Myeloma Cells.

In multiple myeloma (MM), homeostasis is largely maintained by misfolded protein clearance via the proteasomal and aggresomal pathways. Histone deacetylase 6 (HDAC6) binds polyubiquitinated proteins and dynein motors and transports this protein cargo to the aggresome for further degradation. Accordingly, a combination of an HDAC6 inhibitor and bortezomib (BTZ) could increase ubiquitinated protein accumulation, leading to further apoptosis. Here we evaluated the anti-MM activity of MPT0G413, a novel specific HDAC6 inhibitor, using in vitro and in vivo models. MPT0G413 treatment more significantly inhibited cell growth in MM cells than in normal bone marrow cells. Furthermore, the combination of MPT0G413 and BTZ enhanced polyubiquitinated protein accumulation and synergistically reduced MM viability, increased caspase-3, caspase-8, caspase-9 levels, and cleaved poly (ADP) ribosome polymerase and also inhibited adherence of MM cells to bone marrow stromal cells (BMSC) and reduced VEGF and IL-6 levels and cell growth in a co-culture system. The combination treatment disturbed the bone marrow microenvironment and induced synergic, caspase-dependent apoptosis. Xenograft tumor growth significantly decreased in combination-treated SCID mice. In conclusion, MPT0G413 and BTZ synergistically inhibit MM viability, providing a framework for the clinical evaluation of combined therapies for MM.

The anticancer effects of MPT0G211, a novel HDAC6 inhibitor, combined with chemotherapeutic agents in human acute leukemia cells.

BACKGROUND: There are some limitations of standard chemotherapy for acute leukemia. Vincristine and doxorubicin are commonly used for acute leukemia, but they may induce serious side effects such as cardiomyopathy and neurotoxicity. Furthermore, chemotherapy resistance occurs more and more frequently. Therefore, effective treatment strategies are needed. Histone deacetylase 6 inhibition is considered as a potential therapeutic strategy for acute leukemia, since it is observed that HDAC6 is overexpressed in acute leukemia and regulates tumor survival. Combination therapy for cancer is used to minimize adverse drug effects, reduce drug dosage, enhance efficacy, and prevent drug resistance. In order to improve efficacy of chemotherapy agents of acute leukemia, this study will investigate the effects of combination MPT0G211, a novel histone deacetylase 6 inhibitor, with doxorubicin or vincristine on human acute leukemia cells. RESULTS: MPT0G211 combined with doxorubicin induces DNA damage response on human acute myeloid leukemia cells. MPT0G211 can additionally increase Ku70 acetylation and release BAX to mitochondria. Ectopic expression of HDAC6 successively reversed the apoptosis triggered by the combined treatment. Moreover, co-treatment of MPT0G211 and vincristine may alter microtubule dynamics, triggering acute lymphoblastic leukemia cells arrest in mitotic phase followed by induction of the apoptotic pathway. Finally, MPT0G211 plus doxorubicin or vincristine can significantly improve the tumor growth delay in a tumor xenograft model. CONCLUSIONS: Collectively, our data highlighted that MPT0G211 in combination with chemotherapy drugs has significant anticancer activity, suggesting a novel strategy for the treatment of acute leukemia.

A Novel Dual HDAC6 and Tubulin Inhibitor, MPT0B451, Displays Anti-tumor Ability in Human Cancer Cells in Vitro and in Vivo.

The combination cancer therapy is a new strategy to circumvent drug resistance for the treatment of high metastasis and advanced malignancies. Herein, we developed a synthesized compound MPT0B451 that display inhibitory effect against histone deacetylase (HDAC) 6 and tubulin assembly. Our data demonstrated that MPT0B451 significantly inhibited cancer cell growths in HL-60 and PC-3 cells due to inhibition of HDAC activity. MPT0B451 also markedly increased caspase-mediated apoptosis in these cells. The cell cycle analysis showed mitotic arrest induced by MPT0B451 with enhanced expression of G2/M transition proteins. Moreover, molecular docking analysis supported MPT0B451 as a dual HDAC6 and tubulin inhibitor. Finally, MPT0B451 led to tumor growth inhibition (TGI) in HL-60 and PC-3 xenograft models. These findings indicated that MPT0B451 has dual inhibition effects for HDAC6 and tubulin, and also contributed to G2/M arrest followed by apoptotic induction. Together, our results suggested that MPT0B451 may serve as a potent anti-cancer treatment regimen in human prostate cancer and acute myeloid leukemia.

1-Aroylindoline-hydroxamic acids as anticancer agents, inhibitors of HSP90 and HDAC.

A series of 1-aroylindoline-hydroxamic acids have been synthesized in the present study. The results of the biological evaluation led to the identification of compound 12 as dual HDAC6/HSP90 inhibitor. Compound 12 displayed striking inhibitory effects towards the HDAC6 isoform and HSP 90 protein with IC50 values of 1.15 nM (HDAC6) and 46.3 nM (HSP90). Compound 12 also exhibited 113, 139 and 246 fold higher selectivity for HDAC6 over HDAC 1, HDAC 3 and HDAC 8 isoforms and was endowed with significant cytotoxic effects with GI50 values ranging 1.04-1.61 µM against lung A549, colorectal HCT116, leukemia HL60, and EGFR T790M mutant lung H1975 cell lines. Another interesting finding of the study was substantial cytotoxic effects of compounds particularly against lung H1975 (NSCLC) cell lines with IC50 = 0.26 µM which may be mediated through HSP90 inhibition. Compound 8 as such was devoid of HDAC inhibitory activity.

4-Indolyl-N-hydroxyphenylacrylamides as potent HDAC class I and IIB inhibitors in vitro and in vivo.

A series of 4,5-indolyl-N-hydroxyphenylacrylamides, as HDAC inhibitors, has been synthesized and evaluated in vitro and in vivo. 4-Indolyl compounds 13 and 17 functions as potent inhibitors of HDAC1 (IC50 1.28 nM and 1.34 nM) and HDAC 2 (IC50 0.90 and 0.53 nM). N-Hydroxy-3-{4-[2-(1H-indol-4-yl)-ethylsulfamoyl]-phenyl}-acrylamide (13) inhibited the human cancer cell growth of PC3, A549, MDA-MB-231 and AsPC-1 with a GI50 of 0.14, 0.25, 0.32, and 0.24 µM, respectively. In in vivo evaluations bearing prostate PC3 xenografts nude mice model, compound 13 suppressed tumor growth with a tumor growth inhibition (TGI) of 62.2%. Immunohistochemistry of protein expressions, in PC-3 xenograft model indicated elevated acetyl-histone 3 and prominently inhibited HDAC2 protein expressions. Therefore, compound 13 could be a suitable lead for further investigation and the development of selective HDAC 2 inhibitors as potent anti-cancer compounds.

Anti-leukemia effects of the novel synthetic 1-benzylindole derivative 21-900 in vitro and in vivo.

Cancers are the major cause of death worldwide. Chemotherapy using cytotoxic drugs and targeted therapy is required when surgery is difficult, ineffective, or impossible. We previously synthesized the novel synthetic 1-benzylindole derivative 21-900 and found that it inhibits histone deacetylase (HDAC) activities and tubulin assembly. Here we tested its effects on the human leukaemia cell lines HL-60 and MOLT-4 in vitro and in vivo. We found that its potent cytotoxic effects were mediated through cell cycle arrest at the G2/M phase, which increased the population of sub-G1 cells, leading to apoptosis. Further, tubulin was depolymerized by 21-900 in a manner similar to that of vincristine, leading to disruption of microtubule dynamics and increased levels of the mitotic marker MPM-2. Further, 21-900 increased the expression of cleavage form of poly (ADP-ribose) polymerase (PARP), caspase 3, 7 (cleavage form), and pro-apoptotic protein BAK and decreased the expression of pro-survival BCL-2-family proteins BCL-2, MCL-1, and BID pro-form, leading to the induction of apoptosis. The growth of tumours in nude mice formed by xenografts of HL-60 and MOLT-4 cells was significantly inhibited by 21-900 without causing the mice to lose body weight. These findings indicate that 21-900 may serve as a potent anti-leukaemia drug.