Anti-Cancer Agents in Medicinal Chemistry (Formerly Current Medicinal Chemistry - Anti-Cancer Agents) - Volume 21, Issue 10, 2021

Background: In recent years, the emergence of stimuli-responsive nanoparticles has made drug delivery more efficient. As an intelligent and effective targeted delivery platform, it can reduce the side effects generated during drug transportation while enhancing the treatment efficacy. The stimuli-responsive nanoparticles can respond to different stimuli at corresponding times and locations to deliver and release their drugs and associated therapeutic effects. Objective: This review aims to inform researchers on the latest advances in the application of dual-stimuli responsive nanoparticles in precise drug delivery, with special attention to their design, drug release properties, and therapeutic effects. Syntheses of nanoparticles with simultaneous or sequential responses to two or more stimuli (pH-redox, pH-light, redox-light, temperature-magnetic, pH-redox-temperature, redox-enzyme-light, etc.) and the applications of such responsivity properties for drugs control and release have become a hot topic of recent research. Methods: A database of relevant information for the production of this review was sourced, screened and analyzed from Pubmed, Web of Science, SciFinder by searching for the following keywords: “dual-stimuli responsive”, “controlled release”, “cancer therapy”, “synergistic treatment”. Results: Notably, the nanoparticles with dual-stimuli responsive function have an excellent control effect on drug delivery and release, playing a crucial part in the treatment of tumors. They can improve the encapsulation and delivery efficiency of hydrophobic chemotherapy drugs, combine chemo-photothermal therapies, apply imaging function in the diagnosis of tumors and even conduct multi-drug delivery to overcome Multi-Drug Resistance (MDR). Conclusion: With the development of smart dual-stimuli responsive nanoparticles, cancer treatment methods have become more diverse and effective. All the stimuli-responsive nanoparticles functionalities exhibit their characteristics individually within the single nanosystem.

Background: One of the most common tumors of the central nervous system is Glioblastoma (GBM). Objective: There is not still an appropriate cure for this malignant tumor. Plant-derived natural products have demonstrated great potential in cancer therapy, and Resveratrol (Res) is among them. Therefore, the current study focused on the protective effect of resveratrol against glioblastoma and its underlying mechanism. Methods: PubMed, Medline, Scopus, Web of Science, and Google Scholar were searched by using the following keywords: Resveratrol, Glioblastoma, Brain tumor, Cancer therapy, Medicinal herbs to July 2020. Results: Res is a non-flavonoid polyphenol responsible for the protection of plants against pathogen attacks. Res has multiple pharmacological effects, including antioxidant, anti-inflammatory, anti-diabetic, and anti-tumor. Res is capable of penetration into the blood-brain barrier, making it suitable for brain tumor therapy. Besides, Res targets various molecular signaling pathways in cancer therapy. Conclusion: In the present review, it was found that Res administration is beneficial in GBM therapy by inhibition of proliferation, viability, and migration via modulation of molecular pathways.

Background: The persistence of breast cancer as the leading cause of mortality among women, coupled with drug resistance to tamoxifen, the standard endocrine therapy for the disease, exacts continuous attention. To this effect, molecular hybridisation offers an attractive route to drugs with improved bioactivity profiles. Objective: The primary goal of this study was to examine the potential of 1H-1,2,3-triazole linked quinolineisatin molecular hybrids as drug candidates against breast cancer and Methicillin-Resistant Staphylococcus aureus (MRSA) cells. Methods: The quinoline-isatin hybrids were synthesised via click chemistry-mediated molecular hybridisation strategy. Anti-breast cancer activity was determined in 3-(4,5-dimethylthiazol-z-yl)-2,5-diphenyltetrazolium bromide (MTT) assay using Estrogen-Responsive (ER+) MCF-7 and MDA-MB-231 (Triple-Negative Breast Cancer -TNBC) cells, while antimicrobial efficacy was established via the broth dilution method. Also, the toxicity profile of potent compounds to non-cancerous cells was determined using human embryonic kidney cells (HEK293) and human Red Blood Cells (hRBCs). In silico techniques were employed to predict the druglike properties of potent compounds and understand their binding modes with Estrogen Receptor alpha (ERα). Results: Compounds 7g-i exhibited the strongest cytotoxicity to MCF-7 cells with IC50 values of 23.54, 23.66, and 32.50μM, respectively. Interestingly, compound 7h also emerged as the best drug candidate against MDAMB- 231 and MRSA cells with IC50=71.40μM and MIC80=27.34μM, respectively. Structure-activity relationship analysis revealed that quinoline-2-carbaldehyde and 5,7-disubstituted isatin moieties confer desirable potency. These compounds showed no significant cytotoxic or haemolytic effects on HEK293 or hRBCs in vitro at their active concentrations; hence, eliciting their selectivity for cancer cells. In silico studies also presented the drugability of potent compounds and the likely structural features interacting with amino acid residues at the ligandbinding domain of ERα. Conclusion: These results suggest that the identified 1H-1,2,3-triazole-linked quinoline-isatin hybrids are viable chemotypes that can be adopted as templates for the development of new anti-breast cancer and anti-MRSA agents.

Objective: To investigate the effects of Phycoerythrin (PE) on the human ovarian cancer cell line SKOV-3 and its antitumor mechanisms from a transcriptional point of view. Methods: SKOV-3 cells were exposed to different concentrations of phycoerythrin. The efficiency of this treatment was evaluated through cell growth inhibition, changes in cell morphology, apoptosis and intracellular ROS levels. High throughput sequencing (RNA-seq) was performed to screen Differentially Expressed Genes (DEGs), which was verified using RT-PCR and Western blotting. Results: PE showed a significant inhibitory effect on the growth of SKOV-3 cells in a time- and dose-dependent manner. H staining, electron microscopy and flow cytometry revealed that PE induced apoptosis in SKOV-3 cells. Transcriptome analysis showed that 2963 genes were differentially expressed between untreated or PEtreated cells. GO and KEGG pathway analyses identified 16 classical pathways that were enriched. We verified 8 DEGs including, JNK, GADD45A, EDEM2, RAD23, UBQLN, CAPN1, XBP1, and OS9. These results were consistent with the results from transcriptional sequences. Conclusion: The inhibitory effect of PE on SKOV-3 cells was a result of interaction with multiple pathways and signaling molecules. Among these, the ROS/JNK/Bcl-2 signaling pathway, upregulation of JNK, GADD45A and RAD23 as well as downregulation of XBP1 and OS9 played a critical role in the PE -induced apoptosis in human ovarian cancer cells.

Background: Triple Negative Breast Cancers (TNBCs) have high morbidity and shorter survival rate in the population. These types of cancers have high aggressiveness, lymphatic invasion, and absence of receptors. The treatment options for these types of cancers are also scarce. Several studies have been conducted to investigate the effectiveness of seeds of Annona muricata for its anti-cancer activities in various cancer cell lines, such as lung A549, breast MCF7, colon HT-29, oral KB, and human hepatoma cell lines. But works related to its anti-cancer effect and mechanism of action in TNBCs have not been elucidated. Objective: The present study was undertaken to evaluate the in vitro, in vivo, and in silico anti-cancer potential of chloroform fraction of methanolic extract of seeds of Annona muricata (CMAM) against TNBC along with elucidation of its mechanistic pathway. Methods: In vitro cytotoxicity- and antiproliferative- studies in three triple-negative breast cancer cell lines were conducted using the MTT and SRB assays, respectively. The mechanism through which CMAM exerts its pharmacological effect was elucidated in vitro employing cell morphological assessment studies using Acridine Orange/Ethidium Bromide (AO/EB), intracellular reactive oxygen species assay, DNA fragmentation assay, agarose gel electrophoresis, terminal deoxynucleotidyl Transferase dUTP Nick End Labeling (TUNEL) assay, cell cycle analysis, annexin binding assay, and caspase-activated mitochondria-mediated apoptotic assays using western blot. In vivo evaluation in 4T1 induced murine mammary tumor model was also conducted. Phytoconstituents in CMAM were analyzed using liquid chromatography mass spectroscopy. In silico binding studies with various annonaceous acetogenins against BCL-2 and cyclin E were performed. Results: Cytotoxicity studies in MDA-MD-231, 4TI, and BT-549 revealed the IC50 value of CMAM to be 2.5±0.14, 4.8±0.3, and 4.5±0.16μg/mL, respectively. Anti-proliferative studies in 4T1, MDA-MB-231, and BT- 549 revealed the GI50 values to be 0.128+0.03, 18.03+0.20, 0.95+0.04μg/mL, respectively. CMAM exhibited its cytotoxicity through the lysis of cell membrane, ROS dependent caspase-activated mitochondria-mediated apoptosis, and arresting the S phase of the cell cycle. In vivo evaluation also supported the tumoricidal property of CMAM, as evidenced by a reduction in tumor volume and serum biomarkers. Histopathologically, there was a marked reduction in cellularity, nuclear chromatin condensation, and a few normal cells in the group treated with CMAM at a dose of 31mg/Kg. Phytoconstituent evaluation has revealed the presence of annonaceous acetogenins in CMAM. Among the various annonaceous acetogenins, muricatacin alone showed lipophilicity and binding affinity towards BCL-2 and cyclin E1. Conclusion: The current study shows the effectiveness of CMAM against TNBC both in vitro and in vivo. This anticancerous effect of CMAM could be by virtue of its ROS dependent caspase-activated mitochondriamediated apoptosis and the S-phase arrest of the cell cycle in the TNBCs. Our results indicate that the presence of annonaceous acetogenins, especially muricatacin, could be contributing to this anticancerous effect of CMAM. Thus, muricatacin could be a potential candidate for the targeted therapy of TNBCs.

Background: There is an urgent need to devise improved alternatives for the efficient delivery of drugs to develop improved therapeutic interventions against cancers. Nanotechnology-based drug delivery vehicles are in-use with obvious issues of toxicity and bio-distribution. Therefore, green synthetic routes are being deployed to replace the conventional nanoparticle formulations for effective drug delivery aiming at developing interventional strategies against cancer. Objective: A simple, viable, and fast approach was used for the green synthesis of silver nanoparticles (AgNPs) using aqueous leaf-extract of Viburnum nervosum (VN) and to explore the anti-cancer potential of the crude extract of VN. Methods: Silver NPs were synthesized by reacting silver nitrate (AgNO3) with leaf extract of VN. Various analytical techniques were used to characterize the AgNPs. Finally, the anti-cancer potential of VN was observed when delivered through AgNPs. Results: The surface plasmon spectra for AgNPs exhibited absorbance peak at 445 nm, and Fourier-Transform Infrared Spectroscopy investigation revealed the presence of biomolecules acting as an effective reducing and capping agent for converting silver nitrate to AgNPs. Further, our results suggest the spherical size of synthesized AgNPs ranging from 12-17 nm. Moreover, in vitro studies conducted for VN extract with breast (MCF-7) and epidermal carcinoma (A431) cells showed biocompatibility. Conclusion: Doxorubicin loaded AgNPs documented an increased bioavailability of the drug compared to the free drug, suggesting the use of AgNPs as “novel drug delivery vectors”.

Background: β-Cyclodextrin, a cyclic oligosaccharides having 7 macrocyclic rings of glucose subunits usually linked together by α-1,4 glycosidic bond, bears characteristic chemical structure, with an exterior portion as hydrophilic to impart water solubility and interior cavity as hydrophobic, for hosting the hydrophobic molecules. Objective: In the present work binding affinities and interactions between various anti-cancerous drugs and β- cyclodextrin using molecular docking simulations was examined for the bioavailability enhancement of cytotoxic drugs through improved solubility for the treatment of breast cancer. Methods: Molegro Virtual Docker, an integrated software was used for the prediction and estimation of interaction between β-cyclodextrin and anti cancerous drugs. Results: Out of tested anti cancerous drug, Olaparib having pyridopyridazione scaffold possess highest MolDock (-130.045) and Re-ranks score (-100.717), ensuring strong binding affinity. However, 5-Fluoro Uracil exhibited the lowest MolDock score (-61.0045), indicating weak or no binding affinity, while few drugs showed no H-bond interaction with the β-cyclodextrin. Conclusion: The binding conformations of anti cancerous drugs obtained from the present study can be selected for the development of improved formulation having superior solubility which will lead to attain better pharmacological profile with negligible toxicity.

Background: Inhibition of autophagy is reported to be a therapeutically effective strategy in overcoming resistance that is a deadly outcome in cancer. One of the most common reasons for chemo-resistance to treatment is the patients with tumors exhibiting a KRAS mutation, which occurs in approximately 40% of colorectal cancer patients. Objective: Hence, we assessed whether a Palladium (Pd)(II) complex is a promising anticancer complex, compared to 5-fluorouracil in KRAS wt HT-29 and KRAS mutant HCT-15 cells. Methods: HCT-15 and HT-29 cells were used for colorectal cancer and Chloroquine (CQ) was used as an inhibitor of autophagy. In this context, cells were treated with Pd(II) complex and 5-FU in combination with CQ for 48h and cell viability was measured by SRB assay. Cell death mode was examined with M30 and M65 ELISA assays, using annexin V/propidium iodide. Autophagy was determined by Acridine Orange (AO) staining. Furthermore, the expressions of various autophagy and apoptosis-related proteins were evaluated with Western blotting. Luminex assay and the level of Reactive Oxygen Species (ROS) were examined. Results: Cell viability was found to decrease in a dose-dependent manner and CQ enhanced cytotoxic effect in Pd(II) and 5-FU treated cells in colorectal cancer cells. Our data showed that inhibition of autophagic flux significantly increased intrinsic apoptosis through the activation of ROS. We showed that combinatorial treatment with CQ induced apoptosis via the caspase-dependent mitochondrial pathway. Luminex analysis revealed that the combination resulted in a down-regulation of NF-ΚB/AKT/CREB signaling pathways in both cell lines, however, decreased Erk1/2 protein expression was only observed after treatment with CQ combination in HCT-15 cells. Conclusion: We suggest that the inhibition of autophagy along with Pd(II) and 5-FU treatment has a synergistic effect on KRAS-mutant colorectal cancer cells. Autophagy inhibition by CQ promotes apoptosis via blockade of the NF-ΚB/AKT/CREB and activation of ROS.

Background: Indole-based heterocyclic compounds play important roles in pharmaceutical chemistry due to their unexpected biological and pharmacological properties. Objective: Herein, we describe novel biological properties (antioxidant, antimicrobial and anti-cancer) of 3- bromo-1-ethyl-1H-indole (BEI) structure. Methods: BEI was synthesized from 1-Methyl-2-phenylindole and N-bromosuccinimide and was characterized by using 1H and 13C NMR. Cytotoxicity was determined by MTT assay. Apoptosis analysis of BEI was determined by Arthur™ image-based Cytometer. Different methods were applied to assess the antioxidant activity of BEI. Molecular docking studies were conducted to determine the interactions of bonding between GST isozymes and BEI. Results: According to the antioxidant and antimicrobial activity assays, BEI compound showed reduced total antioxidant activity compared to the Trolox standard, whereas it showed moderate antimicrobial activity against Aspergillus niger and Phytophora eryhtrospora. Notably, the BEI compound demonstrated substantial selective cytotoxicity for the first time towards cancer cell lines, and there existed a significant decrease in the percentage of live cells treated with BEI, in comparison to the control ones. Interestingly, BEI exhibited a promising glutathione S-transferase isozymes inhibition. Conclusion: The results of this study suggest that BEI seems to be a promising molecule to be used in the design of new anti-cancer agents that provide superiority to present commercial anti-cancer drugs.

Background and Objective: Curcumin is an effective anti-cancer agent used in thyroid cancer treatments. However, its use in clinical applications is limited due to low solubility and bioavailability. In this study, a novel combination strategy was applied by combining curcumin with Suberoylanilide Hydroxamic Acid (SAHA) to increase both bioavailability of curcumin and the efficiency of SAHA, which have limited efficiency when used alone. Methods: MTT assay was used to determine the cell viability of B-CPAP cells upon treatment with SAHA, curcumin and their combinations. Synergistic interactions between two agents were analyzed by Calcusyn software. Apoptosis and cell cycle assays were measured by flow cytometry. Expressions of apoptotic and cell cyclerelated proteins (PARP, P21/CDKN1A/WAF1, P27/KIP1) were examined by western blot analysis. Broth microdilution assay was performed to determine Minimum Inhibitory Concentration (MIC) values against S. aureus. Results: Based on MTT assay, IC50 values for SAHA and curcumin were determined as 0.91μM and 20.97μM, respectively. The combination index CI value was determined as 0.891 in B-CPAP cells, which demonstrate synergistic activity. The apoptotic effect was achieved by combination treatment (51.85%) on B-CPAP cells using half of the dose required for SAHA and curcumin alone. Combination treatment showed a significant increase in the percentage of B-CPAP cells in the S-phase due to cell arrest. Cleaved-PARP, P21/CDKN1A/ WAF1 and P27/KIP1 protein expressions were upregulated. Curcumin was found to have better anti-microbial activity than SAHA as having a lower MIC value, and checkerboard synergy analysis revealed that the two compounds co-operate synergistically for the in vitro killing of S. aureus. Conclusion: In the present study, synergistic combinations of SAHA and curcumin were shown to have both anti-cancer and antibacterial activities that would provide a novel thyroid cancer treatment strategy.

Background: Curcumin is a natural polyphenol and lead compound of the rhizomes of curcuma longa and it has been widely used for pharmacological activities. Objective: In this study, a series of novel derivatives of curcumin, with this group linked to a 2-amino-4- phenylpyran-3-carbonitrile system, have been synthesized and tested for their antitumor activities in vitro against a panel of three human cancer cell lines (MCF-7, A2780, and U-87MG). Methods: The in vitro cytotoxic activity of the synthesized compounds was tested on three cancer cell lines (MCF-7, A2780, and U-87MG) using MTT colorimetric assay. Meanwhile, the ability of the active compounds to induce apoptosis in cancer cells was investigated by examination of caspase-3 and caspase-9 and mitochondrial membrane potential assay. Results: Under relatively mild conditions in ethanol, the reaction of a series of substrates afforded the corresponding derivatives of curcumin mostly in good yields (13 analogues, 48-94% yields). Bioassay results indicated that compounds L6 (para-Bromo), L9 (para-Nitro) and L12 (meta-Methoxy) were the most active members in this study demonstrating potent activities against A2780 cancer cells and experimental results of fluorescent staining and flow cytometry analysis revealed that L6 and L9 could induce apoptosis in A2780 cells with apoptosis ratios of about 40% and 46%, respectively at 24h of treatment at 15.35μM and 23μM in A2780 cells. On the other hand, they could increase the caspase-3 activity slightly (10%), while having no significant impact on the activities of caspase-9. Conclusion: Those two derivatives could be considered as useful templates for future development to obtain more potent antitumor agents.

Background & Objective: Glycosyl heterocycles, being as nucleoside analogs with modified glycon and hybrid heterocycle motifs, are of considerable interest, and thus, the targeted compounds were synthesized via a convenient and efficient approach. Methods: New indolyl-thiadiazolyl thioglycosides scaffolds were synthesized, starting with the reaction of indole-3-carbaldehyde with 2-aminothiadiazole-5-thiole followed by glycosylation and deprotection. Likewise, new molecular hybrids comprising indole, thiadiazole, triazole and glycosyl moieties were synthesized utilizing click chemistry strategy. The cytotoxic activities of the newly synthesized compounds were studied on colon carcinoma HCT116, breast carcinoma MCF-7, lung carcinoma A549 and hepatocellular carcinoma HepG2 cell lines using Sulphorhodamine-B (SRB) assay. Results: The 1,3,4-thiadiazole thioglycoside and the 1,2,3-triazole N¹-glycoside possessing xylose moiety, compounds 8 and 15 revealed the most potent bio-activity among the new chemical entities; therefore, they undertook for further analysis of apoptosis. Conclusion: IC50s of Compound 8 were 38, 36, 33 and 158μg/ml, while they were 41, 44, 32 and 25μg/ml for compound 15 on HepG2, MCF7, HCT116 and A549 cell lines, respectively; furthermore, the total apoptosis rate (%) for control untreated cells were 9.63, 28.4, 25.4 (%), compounds 8 and 15 respectively, they produced a significant increase in total and early apoptosis rate (%) compared to control (P=0.0001). At the same time, no significant difference was detected in the late apoptosis rate (%), which means that both derivatives have the potential to be developed into potent anticancer agents.