Anti-Cancer Agents in Medicinal Chemistry (Formerly Current Medicinal Chemistry - Anti-Cancer Agents) - Volume 21, Issue 14, 2021

Background: Natural products and their molecular frameworks have been explored as invaluable sources of inspiration for drug design by means of structural modification, computer-aided drug design, and so on. Scopoletin extracting from multiple herbs exhibits potential anti-cancer activity in vitro and in vivo without toxicity towards normal cells. Objective: The study aims to obtain new scopoletin derivatives with enhanced anti-cancer activity. We performed chemical structure modification and researched the mechanism of anti-tumor activity. Methods: In this study, we considered scopoletin as a lead compound, designed and synthesized a series of scopoletin derivatives via introducing different heterocyclic fragments, and their chemical structures were characterized by NMR spectra (¹H NMR and ¹³C NMR) and HRMS(ESI). The antiproliferative activity of target compounds in four cancer cell lines (MDA-MB-231, MCF-7, HepG2, and A549) was determined by the MTT assay. Compound 11b was treated with Ac-cys under different reaction conditions to explore the thiol addition activity of it. The Annexin V/PI and JC-1 staining assay were performed to investigate the anti-tumor mechanism of 11b. Results: Novel compounds 8a-h and 11a-h derivatives of scopoletin were synthesized. Most of the target compounds exhibited enhanced antiproliferative activity against different cancer cells and reduced toxicity towards normal cells. In particular, 11b displayed the optimal antitumor ability against breast cancer MDA-MB- 231 cells with an IC50 value of 4.46 μM. Compound 11b also cannot react with Ac-cys under the experimental condition. When treated with 11b for 24 h, the total apoptotic cells increased from 10.8% to 79.3%. Besides, 11b induced the depolarization of mitochondrial membrane potential. Conclusion: Compound 11b was more active than other derivatives, indicating that the introduction of thiophene fragment was beneficial for the enhancement of antitumor effect, and it was also not an irreversible inhibitor based on the result that the α, β-unsaturated ketones of 11b cannot undergo Michael addition reactions with Accys. Furthermore, studies on the pharmacological mechanism showed that 11b induced mitochondrial depolarization and apoptosis, which indicated that 11b killed cancer cells via a mitochondrial apoptotic pathway. Therefore, in-depth research and structure optimization of this compound is warranted.

Epidermal Growth Factor Receptor (EGFR), a type-I transmembrane protein with intrinsic tyrosine kinase activity, is activated by peptide growth factors such as EGF, epigen, amphiregulin, etc. EGFR plays a vital role in regulating cell growth, migration, and differentiation in various tissue-specific cancers. It has been reported to be overexpressed in lung, head, and neck, colon, brain, pancreatic, and breast cancer that triggers tumor progression and drug resistance. EGFR overexpression alters the signaling pathway and induces cell division, invasion, and cell survival. Our prior studies demonstrated that EGFR inhibition modulates chemosensitivity in breast cancer stem cells, thereby serving as a potential drug target for breast cancer mitigation. Tyrosine kinase inhibitors (Lapatinib, Neratinib) and monoclonal antibodies (Trastuzumab) targeting EGFR have been developed and approved by the US FDA for clinical use against breast cancer. This review highlights the critical role of EGFR in breast cancer progression and enumerates the various approaches being undertaken to inhibit aggressive breast cancers by suppressing the downstream pathways. Furthermore, the mechanisms of action of potential molecules at various stages of drug development, as well as clinically approved drugs for breast cancer treatment, are illustrated.

Background: Cancer is a widespread fatal disease associated with the abnormal growth of cells in the body. Objectives: This article represents applications of biologically synthesized silver nanoparticles and their mode of action in cancer therapy. Methods: Nanomedicines have been proved to be an effective therapy in the treatment of the disease because of a wide range of applications. Due to the small shape and size, these nanoparticles are emerging to be of novel importance. They are abundantly found in various resources with easy extraction. Results: Biologically synthesized silver nanoparticles are safe for humans as well as for the environment. They may replace the harmful therapies like chemotherapy, etc. used in cancer treatment due to the severe side effects associated with it. Sometimes patient may die because of the side effects. Conclusion: These green nanoparticles have great potential to treat and diagnose different cancers. This article laid a research opportunity for the diagnosis and treatment of cancer.

Background: Cancer accounts for several deaths each year. There are multiple FDA approved drugs for cancer treatments. Due to the severe side effects and multiple drug resistance, the current drug therapies become ineffective. So, the newer moieties with fewer toxic effects are necessary for the development. Objective: The mechanism of indole derivatives as anti-cancer agents with their major target is explored in detail in this article. Methods: Recent advances and mechanism of indole derivatives as anti-cancer agents are reviewed. This review suggests a detailed explanation of multiple mechanisms of action of various indole derivatives: cell cycle arrest, aromatase inhibitor estrogen receptor regulator, tubulin inhibitor, a tyrosine kinase inhibitor, topoisomerase inhibitors, and NFkB/PI3/Akt/mTOR pathway inhibitors, through which these derivatives have shown promising anti-cancer potential. Results: A full literature review showed that the indole derivatives are associated with the properties of inducing apoptosis, aromatase inhibition, regulation of estrogen receptor and inhibition of tyrosine kinase, tubulin assembly, NFkB/PI3/Akt/mTOR pathway, and HDACs. These derivatives have shown significant activity against cancer cell lines. Conclusion: Indole derivatives seem to be important in cancer via acting through various mechanisms. This review has shown that the indole derivatives can further be explored for the betterment of cancer treatment, and to discover the hidden potential of indole derivatives.

Background: Xanthones are a class of heterocyclic natural products, which are promising sources of anti-cancer leads. Phomoxanthone B (PXB) and Phomoxanthone A(PXA)are xanthone dimers. PXA is wellstudied as an anti-cancer agent, but PXB is not. In our study, PXB was isolated from the endophytic fungus Phomopsis sp. By254. Objective: The purpose of this study was to identify the underlying anti-tumor mechanisms of PXB in breast cancer MCF7 cell line. Methods: Apoptosis, cell cycle, proliferation, invasion, and migration assays were used to assess the anti-tumor activity of PXB. RNA sequencing was used to analyze the effect of PXB treatment on gene expression in MCF7 cells. Results: PXB showed cytotoxicity towards a variety of tumor cells, especially MCF7 cells. PXB inhibited the migration and invasion, arrested cell cycle at G2/M phase, and induced apoptosis associated with caspase-3 activation in MCF7 cells. The detailed transcriptome analysis revealed that PXB affected several pathways related to tumorigenesis, metabolisms, and oxidative phosphorylation in MCF7 cells. KEGG transcriptome analysis revealed that PXB upregulated pro-survival signal pathways, such as MAPK, PI3K-AKT, and STAT3 pathways. We found that PXB also significantly upregulated the expression of IL24, DDIT3, and XAF1, which may contribute to PXB-induced apoptosis. We further found that PXB may downregulate oxidative phosphorylation by decreasing the expression of electron transport chain genes, especially MT-ND1, which is a potential unfavorable prognostic marker for ER-positive breast cancer. Conclusion: PXB exerts strong cytotoxicity against human tumor cells and has a potential for ER-positive breast cancer treatment.

Background: Prostate cancer is one of the most commonly diagnosed cancers and one of the most common causes of cancer-related deaths among men worldwide. Patients who are diagnosed with localized prostate cancer and treated with radical prostatectomy often respond well to therapy. The current standard therapy for prostate cancer involves maximal surgical resection, followed by radiotherapy and chemotherapy. Clarifying the molecular mechanism of tumor proliferation and recurrence becomes more and more important for clinical therapies of prostate cancer. Methods: Quantitative Real-Time PCR and Western-blot were used in the detection of mRNA and protein expression. Lentivirus infection was used to overexpress or knockdown the target gene. Flow cytometry analysis was performed to test protein expression and apoptosis level. Immunohistochemistry was used to identify protein expression in tissue. Statistical differences between the two groups are evaluated by two-tailed t-tests. The comparison among multiple groups is performed by one-way Analysis of Variance (ANOVA) followed by Dunnett’s posttest. The statistical significance of the Kaplan-Meier survival plot is determined by log-rank analysis. Results: In this study, we identified that FOXM1 expression was significantly enriched in prostate cancer compared with normal tissue. Additionally, FOXM1 was functionally required for tumor proliferation and its expression was associated with poor prognosis in prostate cancer patients. Mechanically, FOXM1-dependent regulation of EZH2 is essential for proliferation and progression in prostate cancer. Conclusion: Taken together, our data suggest that oncogenic transcription factor FoxM1 is up-regulated in prostate cancer, suggesting that the growth of cancer cells may depend on FOXM1 activity. FOXM1 may serve as a clinical prognostic factor and a therapeutic target for prostate cancer.

Background: The use of DOX as an anticancer agent is associated with serious side effects on normal cells especially in cardiovascular tissue. Objective: Here, it is proposed that the combination of a low dose of DOX with AgNPs provides ideal cytotoxicity against cancer cells and decreases side effects on normal human cells. This study evaluates the cytotoxic effects of green-synthetized AgNPs (GS-AgNPs) in combination with DOX in cancerous cells (MCF7) and investigates its influences on cell growth and apoptosis in a normal cell line of the heart (H9c2). Methods: We used coffee extracts, as a reducing and stabilizing agent for the green-synthesis of AgNPs. GSAgNPs were characterized by using various analytical methods. MTT assay was used for cell toxicity analysis in cancerous and normal cells. Moreover, Annexin-V /PI staining and mRNA expression of Bax, Bcl2 and p53 were performed for apoptosis measurement in heart normal cell line. Results: GS-AgNPs showed more biocompatibility for normal cells and higher cytotoxicity for cancerous cells compared to that reported for chemically synthesized nanoparticles. Our results also demonstrated that a selected combination of DOX and AgNPs, 20 μM AgNPs / 0.3 μM DOX, had a suitable cytotoxic effect against cancerous cells with a minimum toxic effect on normal cells. So, no significant alteration was observed in cell migration capacity, apoptosis and gene expression of BAX, Bcl-2 and P53 when H9c2 cells were treated with 20 μM AgNPs / 0.3 μM DOX relative to the non-treated control. Conclusion: Finally, it seems that the combination of GS-AgNPs and DOX could be a potent strategy to combat cancer.

Background: Cancer Stem Cells (CSCs) are a subpopulation within the tumor that play a role in the initiation, progression, recurrence, resistance to drugs and metastasis of cancer. It is well known that epigenetic changes lead to tumor formation in cancer stem cells and show drug resistance. Epigenetic modulators and /or their combination with different agents have been used in cancer therapy. Objective: In our study, we scope out the effects of a combination of a histone deacetylases inhibitor, Valproic Acid (VPA), and Cu(II) complex [Cu(barb-ΚN)(barb-Κ2N,O)(phen-ΚN,N’)]·H2O] on cytotoxicity/apoptosis in a stem-cell enriched population (MCF-7s) obtained from parental breast cancer cell line (MCF-7). Methods: The viability of the cells was measured by the ATP assay. Apoptosis was elucidated via the assessment of caspase-cleaved cytokeratin 18 (M30 ELISA) and a group of flow cytometry analysis (caspase 3/7 activity, phosphatidylserine translocation by annexin V-FITC assay, DNA damage and oxidative stress) and 2#136;,7#136;– dichlorofluorescein diacetate staining. Results: The VPA combined with Cu(II) complex showed anti-proliferative activity on MCF-7s cells in a doseand time-dependent manner. Treatment with a combination of 2.5 mM VPA and 3.12 μM Cu(II) complex induced oxidative stress in a time-dependent manner, as well as apoptosis evidenced by the increase in caspase 3/7 activity, positive annexin-V-FITC, and increase in M30 levels. Conclusion: The results suggest that the combination therapy induces apoptosis following increased oxidative stress, thereby making it a possible promising therapeutic strategy for which further analysis is required.

Background: The anti-cancer activity of some lactic acid bacterial strains is well documented in several kinds of literatures. Lactobacillus strains have received considerable attention as a beneficial microbiota. The aim of this study is to evaluate the effects of anti-tumor activities of L. acidophilus ATCC4356 culture supernatants on the MCF-7 human breast cancer cells. Materials and Methods: The anti-cancer effects of 24h and 48h culture supernatants at various concentrations (1.25, 2.5, 5, 10 and 20 μg/ml) were determined by various in vitro and in vivo assays including MTT, tumor volume measurement as well as ^99mTc-MIBI biodistribution in MCF-7 tumor bearing nude mice and histopathology test. For evaluation of the related mechanism of action, quantitative PCR was conducted. Results: The 48h culture supernatants at 10 and 20 μg/ml exhibited significant in vitro inhibition of MCF-7 cell proliferation. However, this inhibition was not observed for HUVEC human endothelial normal cells. Q-PCR indicated that treatment by the supernatant led to a significant downregulation of VEGFR (~ 0.009 fold) and Bcl- 2 (~ 0.5 fold) and upregulation of p53 (~ 1.3 fold). In vivo study using MCF-7 xenograft mouse models demonstrated a reduction in tumor weight and volume by both 24h and 48h supernatants (2 mg/kg) after 15 days. According to the ^99mTc-MIBI biodistribution result, treatment of MCF-7 bearing nude mice with both 24h and 48h supernatant (2mg/kg) led to a significant decrease in tumor uptake compared with the control group. Conclusion: These results suggest that the culture supernatants of L. acidophilus ATCC4356 at suitable concentrations can be considered as a good alternative nutraceutical with promising therapeutic indexes for breast cancer.

Background: Bilirubin has long been exclusively considered as a potentially dangerous sign of liver diseases, but it is currently regarded as a reliable signaling molecule as well. Objective: This study investigated the effects of unconjugated bilirubin on survival, proliferation, apoptotic and cell arrest capacities of melanoma SKMEL-3 and non-melanoma A431 skin cancer cells in comparison with normal Human Dermal Fibroblast (HDF) cells. Methods: The MTT assay test was used to identify survival and the IC50 at various concentrations of bilirubin on SKMEL-3, A431, and HDF cells for 24h and 48h. The comet assay technique was used to investigate genotoxicity effects, and flow cytometry was run to investigate apoptotic and cell arresting effects of bilirubin on the cells. The gene expression of cyclin D1, cyclin E1, survivin, Bcl-2, and p53 was investigated by qRT-PCR. The molecular docking of bilirubin on CDKs (Cyclin-Dependent Kinases 2, 4, and 6) and pro-apoptotic factors Bad, Bak, Bax, Bid, Bik, and Bim was performed by Autodock software version 2. Results: The IC50 of bilirubin on HDF, A431, and SKMEL-3 cells was 125, 115, and 95 μM at 24h and 115, 100, and 75 μM at 48h, respectively. Although cell arrest in the G1 phase occurred in all cells, bilirubin induced genotoxicity and apoptosis in SKMEL-3 and A431 cancer cells more pronouncedly than those in normal HDF cells. Conclusion: Bilirubin led to cell arrest in the G1 phase in SKMEL-3, A431, and HDF cells. Additionally, bilirubin induced apoptotic pathways in SKMEL-3 and A431 cancer cells.

Background: Multiple Myeloma (MM) is a malignant hematologic disorder and the second most common blood cancer. Interleukin-6 (IL-6) has been identified as a crucial factor for the proliferation and survival of MM cells and the overexpression of IL-6 receptor is being studied as a molecular target for therapeutic and diagnostic use in myelomas and other comorbidities. Tocilizumab is a humanized monoclonal antibody that binds IL-6R. Objective: We aim to label and evaluate Fab(Tocilizumab) with ^99mTechnetium or Cy7 as potential MM imaging agents. Methods: IL-6R distribution was analyzed by Laser Confocal Microscopy (LCM) in MM cell lines. Fab(Tocilizumab) was produced by the digestion of Tocilizumab with papain for 24h at 37°C, derivatized with NHS-HYNIC-Tfa and radiolabeled with ^99mTc. Radiochemical stability and in vitro cell assays were evaluated. Biodistribution and SPECT/CT were performed. Also, Fab(Tocilizumab) was labeled with Cy7 for in vivo fluorescence imaging up to 72h. Results: LCM analysis demonstrates IL-6R distribution on MM cell lines. Incubation with papain resulted in complete digestion of Tocilizumab and exhibited a good purity and homogeneity. Radiolabeling with 99mTc via NHS-HYNIC-Tfa was found to be fast, easy, reproducible and stable, revealing high radiochemical purity and without interfering with IL-6R recognition. Biodistribution and SPECT/CT studies showed a quick blood clearance and significant kidney and MM engrafted tumor uptake. Cy7-Fab(Tocilizumab) fluorescent imaging allowed MM1S tumor identification up to 72h p.i. Conclusion: These new molecular imaging agents could potentially be used in the clinical setting for staging and follow-up of MM through radioactive whole-body IL-6R expression visualization in vivo. The fluorescent version could be used for tissue sample evaluation and to guide surgical excision, if necessary.

Background: Mucoadhesive polymers play a critical role in controlled-release tablets for buccal drug delivery. Objective: This research aimed to investigate the characterization and mechanisms of solid lipid particle-based tablets with different mucoadhesive polymers for buccal delivery. Methods: Prednisolone (PSL)-loaded Solid Lipid Particles (SLPs) were conventionally prepared by ultrasonication. The freeze-drying method was used to convert the SLP suspension into a solid dosage form for buccal delivery by using mucoadhesive polymers. Results: All formulations showed over 80% drug release after 6h, which followed immediate and sustained release patterns depending on the SLP type. However, the different polymers in the formulations resulted in different mucoadhesion times and drug release and drug permeability profiles. HPMC 4000 showed higher drug permeation (3327 μg vs. 2589 μg after 6h) but a shorter mucoadhesion time than Carbopol (197 min vs. 361 min). In addition, surface morphology, swelling and erosion, particle size and zeta potential were also noted for the different mechanisms for buccal tablet design with different controlled release profiles. Conclusion: The results of this work indicate a good strategy for the selection of mucoadhesive polymers for SLP-based tablets in improving the bioavailability of poorly water-soluble drugs.

Background: Triple-negative BC is the most aggressive type of breast cancer and its lack of responsiveness to conventional therapies requires screening of new chemical entities. Anti-migratory compounds are promising to treat metastatic cancer since they inhibit one of the main steps of the metastatic cascade. Spirocyclic compounds are non-conventional structures used as building blocks for the synthesis of biologically active molecules and considered interesting structures in the search for new targets in cancer research. Objective: Here, we evaluated the potential of eight synthetic spirocyclohexadienones as cell migration inhibitors. Methods: The anti-migratory ability of compounds was tested by wound healing and Boyden chamber approaches. Experiments in tubulin were performed by fluorescence and tubulin polymerization techniques. Finally, compounds were submitted to cell proliferation inhibition and flow cytometry assays to explore the mechanism by which they inhibit cell migration. Results: Four compounds inhibited cell migration significantly. Analogs containing the 3,4,5-trimethoxyphenil ring at R¹ position were the most potent and, thus, selected for additional experiments. Tubulin polymerization and fluorescence assays highlighted a possible binding of spirocyclohexadienones in the colchicine binding site; however, these compounds did not affect the cell cycle to the same extent as colchicine. Cell proliferation was affected and, notably, the most potent analogs induced apoptosis of tumor cells, suggesting a different mechanism by which they inhibit cell migration. Conclusion: We presented, for the first time, a series of eight synthetic spirocyclohexadienones with the ability to inhibit TNBC cell migration. These compounds represent a new category to be explored as anticancer agents.

Background: Quercetin has potential against the Multidrug Resistance (MDR) phenotype, but with low bioavailability. The increase in the bioavailability can be obtained with nanostructures. Objective: To analyze the effects of quercetin and its nanoemulsion on MDR and non-MDR cells. Methods: We used high-pressure homogenization for nanoemulsion production; Trypan Blue for cytostatic/cytotoxicity assays; Epifluorescence microscope (with specific probes) for apoptosis and DNA damage; Real-Time PCR for gene expression; AutoDock Vina for docking and Flow Cytometry for efflux analysis. Quercetin exerted antiproliferative impact, induced apoptosis, necrosis and DNA damage on cells. Results: Quercetin combined with vincristine showed an effect similar to verapamil (an ABCB1 inhibitor), and docking showed that it binds to ABCB1 in a similar region. Quercetin was also capable of altering ABCB1 gene expression. Quercetin in nanoemulsion maintained the cytotoxic and cytostatic effects of quercetin, which may increase bioavailability. Besides, the unloaded nanoemulsion was able to inhibit per se the efflux activity of ABCB1, demonstrating pharmacological action of this structure. Conclusion: Quercetin may be considered as a prospective drug to overcome resistance in cancer cells and its nanoemulsion can be an alternative for in vivo application.

Background: Liver cancer is one of the most common diseases in the world. At present, the mechanism of autophagy genes in liver cancer is not very clear. Therefore, it is meaningful to study the role and the prognostic value of autophagy genes in liver cancer. Objective: The purpose of this study is to conduct a bioinformatics analysis of autophagy genes related to primary liver cancer for establishing a prognostic model of primary liver cancer based on autophagy genes. Methods: We identified autophagy genes related to the prognosis of liver cancer through bioinformatics methods. Results: Through difference analysis, 31 differential autophagy genes were screened out and then analyzed by GO and KEGG analysis. At the same time, we built a PPI network. For optimizing the evaluation of the prognosis of liver cancer patients, we integrated multiple autophagy genes, after which a prognostic model was established. By using univariate cox regression analysis, 15 autophagy genes related to prognosis were screened out. Then we included these 15 genes into the Least Absolute Shrinkage and Selection Operator (LASSO) and performed a multi-factor cox regression analysis on the 9 selected genes for constructing a prognostic model. The risk score of each patient, who participated in the establishing of the model, was calculated based on 4 genes (BIRC5, HSP8, SQSTM1, and TMEM74). Then the patients were divided into high-risk groups and low-risk groups. In the multivariate cox regression analysis, the risk score was assessed by the independent prognostic factors (HR = 1.872, 95% CI = 1.544 - 2.196, p < 0.001). Survival analysis showed that the survival time of the low-risk group was significantly longer than that of the high-risk group. By combining clinical characteristics and autophagy genes, we constructed a nomogram for predicting the prognosis. The external dataset GSE14520 proved that the nomogram has a good prediction for individual patients with primary liver cancer. Conclusion: This study provided potential autophagy-related markers for liver cancer patients to predict their prognosis and reveal part of the molecular mechanism of liver cancer autophagy. At the same time, certain gene pathways and protein pathways related to autophagy may provide some inspiration for the development of anticancer drugs.

Background: HER2-positive breast cancer patients account for one-fifth of the total breast cancer population. Besides, more anti-HER2-targeting drugs have appeared clinically. Objective: This study aimed to analyze the efficacy and safety of additional anti-HER2 (Human Epidermal growth Factor Receptor 2)-targeting drugs in the treatment of HER2-positive advanced breast cancers. Methods: The following databases were searched for published articles containing data on the efficacy and safety of additional anti-HER2-targeting drugs in HER2-positive advanced breast cancer from the time of their inception until December 2019: PubMed, Web of Science, EBSCO, and Cochrane library. The primary outcomes were Progression-Free Survival (PFS) and Overall Survival (OS). Results: The additional anti-HER2-targeting drugs significantly improved the PFS (HR: 0.66, p<0.001) and OS (HR: 0.77, p<0.001) of HER2-positive advanced breast cancer patients. Regarding drug types, lapatinib was the most effective (HR: 0.53, 95% Cl: 0.39-0.67, p<0.001), followed by pertuzumab (HR: 0.72, 95% Cl: 0.55-0.89, p=0.001). Trastuzumab was the least beneficial (HR: 0.87, 95% Cl: 0.31-1.44, p=0.594). Concerning treatment regimen, first-line treatment (HR: 0.67, 95% Cl: 0.52-0.82, p<0.001) was more effective than non-first-line treatment (HR: 0.82, 95% Cl: 0.71-0.94, p=0.004). The main Adverse Events (AEs) observed were diarrhea and decreased ejection fraction. Conclusion: Additional anti-HER2-targeting drugs can improve long-term prognosis in HER2-positive advanced breast cancers. Besides, they are associated with fewer AEs and are tolerable. Lapatinib is the most effective drug, followed by pertuzumab, whereas trastuzumab is the least effective. Concerning treatment, we recommend the use of anti-HER2-targeting drugs in first-line therapy of HER2-positive advanced breast cancers.