Anti-Cancer Agents in Medicinal Chemistry (Formerly Current Medicinal Chemistry - Anti-Cancer Agents) - Volume 18, Issue 14, 2018

Background: Acute myeloid leukemia is the collective name for different types of leukemias of myeloid origin affecting blood and bone marrow. The overproduction of immature myeloblasts (white blood cells) is the characteristic feature of AML, thus flooding the bone marrow and reducing its capacity to produce normal blood cells. USFDA on August 1, 2017, approved a drug named Enasidenib formerly known as AG-221 which is being marketed under the name Idhifa to treat R/R AML with IDH2 mutation. The present review depicts the broad profile of enasidenib including various aspects of chemistry, preclinical, clinical studies, pharmacokinetics, mode of action and toxicity studies. Methods: Various reports and research articles have been referred to summarize different aspects related to chemistry and pharmacokinetics of enasidenib. Clinical data was collected from various recently published clinical reports including clinical trial outcomes. Result: The various findings of enasidenib revealed that it has been designed to allosterically inhibit mutated IDH2 to treat R/R AML patients. It has also presented good safety and efficacy profile along with 9.3 months overall survival rates of patients in which disease has relapsed. The drug is still under study either in combination or solely to treat hematological malignancies. Molecular modeling studies revealed that enasidenib binds to its target through hydrophobic interaction and hydrogen bonding inside the binding pocket. Enasidenib is found to be associated with certain adverse effects like elevated bilirubin level, diarrhea, differentiation syndrome, decreased potassium and calcium levels, etc. Conclusion: Enasidenib or AG-221was introduced by FDA as an anticancer agent which was developed as a first in class, a selective allosteric inhibitor of the tumor target i.e. IDH2 for Relapsed or Refractory AML. Phase 1/2 clinical trial of Enasidenib resulted in the overall survival rate of 40.3% with CR of 19.3%. Phase III trial on the Enasidenib is still under process along with another trial to test its potency against other cell lines. Edasidenib is associated with certain adverse effects, which can be reduced by investigators by designing its newer derivatives on the basis of SAR studies. Hence, it may come in the light as a potent lead entity for anticancer treatment in the coming years.

The article entitled “Aberrant Sialylation in Cancer Pathology and Metastasis, a Putative Drug Target Candidate”, by Lu D.Y., Lu T.R., Xu B., Varki A., Huang M., Zhu H., Shen Y., Yarla N.S., has been retracted on the request of one of the coauthors Dr. Ajit Varki available at: Anticancer Agents Med Chem. 2018; 18(14): 1952-1961. http://www.eurekaselect.com/165282. The Corresponding Author Dr. Da-Yong Lu has included the name of the co-author Dr. Ajit Varki and Dr. Nagendra Yarla without their consent and the manuscript has been published in the journal Anti-Cancer Agents in Medicinal Chemistry (ACAMC). Kindly see Bentham Science Policy on Article retraction at the link given below: https://benthamscience.com/journals/anti-cancer-agents-in-medicinal-chemistry/editorial-policies/). Submission of a manuscript to the respective journals implies that all authors have read and agreed to the content of the Copyright Letter or the Terms and Conditions. As such this article represents a severe abuse of the scientific publishing system. Bentham Science Publishers takes a very strong view on this matter and apologizes to the readers of the journal for any inconvenience this may cause.

New modifications in nanoparticles changed their applications obviously. Green synthesis of nanoparticles and their biomedical utilizations have been the focus of increasing attention in recent years. Silver nanoparticles (AgNPs) demonstrated surprising effects and many advantageous features for cancer therapy. Investigations indicated the anticancer activity of AgNPs in different ways, comprising cell cycle arrest, DNA damaging and apoptosis, alteration of P53 function, up/down regulation of some important cytokine genes and so on. But some key inquiries like the ability to control the accidental effects of AgNPs, or encompassing process for parcels, which reduces the toxicological profile of nanoparticles, still remained. “Green synthesis” of nanoparticles has been shown to be a kind of approach to resolve the toxicity amounts in a range of 10-18 times. Using distinctive properties of this approach, i.e. as green synthesized silver nanoparticles (G-AgNPs), in order to raise potential therapeutic efficacy, even up to two-fold higher than cis-platin, is going to play a crucial role in cancer treatment and could be considered as a new insight in this field. The current review focuses on the antioxidant activity of G-AgNPs and potential impacts on cancer cells.

Background: Silimarin is the dry mixture of a whole family of natural substances, extracted after the addition of ethanol, methanol, and acetone. Silimarin consists mainly of silibin A and silibin B, as well as other less important compounds. Methods: Silimarin has been demonstrated to “inhibit cell proliferation and to induce apoptosis, while also having anti-angiogenic properties.” The induction of apoptosis in cancer cells has been mediated by the involvement of ER stress. Results: Silibinin has the potential to operate as a STAT3-targeted inhibitor as well as an inhibitor of the upregulation of the immune checkpoint regulator PD-L1 and also EMT regulators, thus being a promising adjuvant in NSCLC. It has also been documented to suppress cancer cells be means of down- regulating actin cytoskeleton and PI3K / Akt molecular pathways. Several studies have demonstrated that silibinin exerts its protective potential partly through interacting with the tumor suppressor gene p53. Conclusions: It is noteworthy that research has been carried out on the enhancement of silimarin’s bioavailability, especially by the preparation of specific nanoformulas, and its probable additional use together with the chemotherapeutic regimens in the near future.

Background: The cause of cervical cancer can be traced to Human Papilloma Virus (HPV) along with other, nonviral factors. The uterine cervix is reactive to hormones, and female hormones have been implicated in cervical cancer pathogenesis. Previous studies have indicated that malignant cervical cells tend to lose Estrogen Receptor alpha (ER-α) expression in the cervical epithelium while maintaining ER-α expression in the stromal cells. Method: We searched the Web of Science, Embase, PubMed, and Wiley Online Library databases to identify potentially relevant articles up to July 4, 2018. Keywords include uterine cervical neoplasms; receptors, estrogen; estrogen receptor alpha; estrogen receptor modulators; estrogens; cervical cancer and estrogen receptor. Result: Discussions on molecular transitions and drug therapies offer insights into cervical cancer and the functions of estrogen receptors. We focus on molecular transitions and drug therapies for cervical cancer and ER-α targets. Finally, the targeting of downstream gene products and/or receptors to aid in cervical cancer prevention and therapy is discussed. Conclusion: Downregulating ER-α expression may be a potential treatment regimen for cervical cancer patients and will be of great significance for patients with cervical cancer who are receiving conventional treatment for nonsurgical treatments.

Emerging evidence present credible support in favour of the potential role of mahanine and girinimbine. Non-toxic herbal carbazole alkaloids occur in the edible part of Murraya koenigii, Micromelum minutum, M. zeylanicum, and M. euchrestiolia. Mahanine and girinimbine are the major potent compounds from these species. In fact, they interfered with tumour expansion and metastasis development through down-regulation of apoptotic and antiapoptotic protein, also involved in the stimulation of cell cycle arrest. Consequently, these compounds were well proven for the in-vitro and in vivo evaluation that could be developed as novel agents either alone or as an adjuvant to conventional therapeutics. Therefore, mahanine and girinimbine analogs have the potential to be the promising chemopreventive agents for the tumour recurrence and the treatment of human malignancies. In this review, an updated wide-range of pleiotropic anticancer and biological effects induction by mahanine and girinimbine against cancer cells were deeply summarized.

Background: MicroRNAs (miRNAs) play an important role in the regulation of various genes involved in cell growth, development and the maintenance of body homeostasis. They are closely linked to different human diseases, particularly in cancers. Amplification and overexpression of some miRNAs that are called ‘oncomiRs’ or down-regulation of tumor suppressor miRNAs are associated with genetic alterations that are sufficient to drive tumorigenesis in humans. Lung cancer is the leading cause of cancer-related deaths worldwide. The high mortality rate of lung cancer is not changed even with recent advances in cancer treatment. Several studies demonstrated that miRNAs are involved in the pathogenesis of lung cancer that they negatively or positively regulate gene and protein expression by acting as oncogenes or tumor suppressors. Objective: This article reviewed the current knowledge on the role of miRNAs and their target genes in lung cancer and discussed the potential use of some miRNAs as novel therapeutic agents in lung cancer. Method: Firstly, we collected and summarized all research and review and research articles in databases including Scopus and PubMed. Then, we used related keywords that are important to lung cancer target therapy and their diagnostic and prognostic values. Results: Based on collected articles and research, recognizing critical microRNA and controlling the expression of this microRNA by antagonist oligonucleotides like antagomiRs or anti-miRs and microRNA mimicking will have a remarkable role in treating lung cancer. Conclusion: Many research studies have shown that a combination of chemotherapy plus knockdown or mimicking microRNA is effective and useful in the cancers treatment like lung cancer.

Background: Certain molecular deviations can lead to the development of breast cancer. For instance, estrogen and estrogen receptors play a significant role in inducing tumor proliferation. However, the efficacy of endocrine therapy through the administration of anti-estrogen drugs, such as Tamoxifen, is challenged by acquired resistance. Methods: Relevant articles were retrieved from Medline and google scholar. All were screened to select the ones discussing the molecular mechanisms of angiogenesis and Tamoxifen resistance. The molecular interactions contributing in the resistant network were studied from the eligible articles. Results: Tamoxifen resistance occurs as a consequence of over-activated signal transduction pathways such as RTK s dependent cascades. It has been shown that microvessel count was greater in Tamoxifen resistant tissues than in responsive ones. Conclusion: In this review, the interaction between estrogen, Tamoxifen, VEGF, and VEGF receptors (VEGFRs) in Tamoxifen resistant cells has been discussed. VEGF and estrogen-independent growth cascades, especially MAPK have a positive feedback loop in Tamoxifen resistant cells. It has been proposed that over-activated pathways in Tamoxifen resistant cells induce pin1 mediated VEGF over-expression, which in turn result in enhanced activation of MAPK.

Background: Gastric adenocarcinoma is one of the most common and lethal cancer types and is known as the second leading cause of cancer-related death of Asian adults, early diagnosis based on either pathology or molecular biology could be one of the most efficient ways to improve the outcomes of gastric adenocarcinoma patients. Methods: Quantitative Real-Time PCR and Western-blot were used in detection of mRNA and protein expression. Lentivirus infection was used to overexpression or knock down target gene. Alarma blue assay was used to monitor cells proliferation. Flow cytometry analysis was performed to test protein expression and apoptosis level. Immunohistochemistry was used to identify protein expression in tissue. Statistical differences between 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: MMP7 as one of the most up-regulated genes in T-DM1 resistant NCI-N87 gastric adenocarcinoma cells compared to matched naïve cell lines. T-DM1 resistant NCI-N87 cell lines by exposed to T-DM1 in vitro. Exogenous overexpression of MMP7 promotes T-DM1 resistance and tumor growth in NCI-N87 cell lines while MMP7 knockdown enhanced sensitivity to T-DM1 in T-DM1 resistant NCI-N87 cell lines established previously. MMP7 was enriched in high WHO grade GC samples and implies poor outcomes for these patients. DKK1 as one of the most correlated genes to MMP7 in gastric adenocarcinoma and knock-down of DKK1 or inhibition of Wnt/β-catenin pathway led to a decreased expression of MMP7 and resistance to T-DM1. Conclusion: DKK1 and Wnt/β-catenin-dependent activation of MMP7 induces T-DM1 resistance and leads to the poor prognosis of gastric adenocarcinoma, which might be a novel potential therapeutical target for T-DM1 resistant gastric adenocarcinoma.

Background: To reduce the nonspecifically distribution of chemotherapeutic agents throughout the whole body, which causes severe toxicity in normal tissues, targeting them towards a receptor overexpressed on tumor tissue, is a promising method for cancer therapy. Objective: The aim of the present study was development of novel copolymeric micelles of raloxifene targeted Styrene Maleic Acid-Poly Amide Ether Ester Imide-Poly Ethylene Glycol (SMA-PAEEI-PEG-RA) and loading them with Docetaxel (DTX). Methods: Successful synthesis of the targeted copolymer was confirmed by FTIR and C-NMR spectroscopy. The micelles physicochemical properties like morphology, particle size, poly dispersity index, zeta potential, drug loading, release, stability, in vitro cytotoxicity and cellular uptake were analyzed. The in vivo antitumor activity of DTX-loaded micelles were assessed and compared with free DTX and non-targeted micelles in breast cancer bearing Balb-c mice. Results: Particle sizes, zeta potentials and the encapsulation efficiency of the drug in targeted micelles were 115.9- 142.8 nm, -4.9 to -12.9 mV, and 54.1-67.8%, respectively. Cell toxicity tests showed that IC50 of DTX-loaded SMAPAEEI- PEG-RA micelles increased five-fold as compared with free DTX. Survival rate of the mice improved more effectively than free DTX so that, the percentage of increase in lifespan (ILS%) and the tumor inhibition ratio (TIR) changed from 41.66% and 51.19% in free drug to 83.33% and 78.57% in the targeted micelles, respectively. Conclusion: Therefore, the raloxifene conjugated PEG-derived micelles may provide a novel and effective delivery system for DTX in breast cancer.

Objective: Breast cancer is one of the most common diseases among women worldwide and it is characterized by a high ratio of malignancy and metastasis and low rate of survival of patients. Due to limited treatment options, the discovery of alternative therapeutic agents and clarifying the molecular mechanism of breast cancer development may offer new hope for its treatment. Lichen secondary metabolites may be one of these therapeutic agents. Methods: In this study, the effects of Vulpinic Acid (VA) lichen secondary metabolite on the cell viability and apoptosis of breast cancer cells and non-cancerous cell line were investigated. Quantitative polymerase chain reaction was also performed to determine changes in the expression of apoptosis-related genes at a molecular level. Results: The results demonstrated that VA significantly inhibited the cell viability and induced apoptosis of human breast cancer cells. The highest rates of decreased growth were determined using the IC50 value of VA for 48h on MCF-7 breast cancer cell. Interestingly, VA treatment significantly reduced cell viability in all examined breast cancer cell lines compared to their non-cancerous human breast epithelial cell line. This is the first study on the investigation of the effects of VA on the molecular mechanisms associated with the expression of apoptosis-related genes in breast cancer cell lines. Results demonstrated that the gene expression of P53 genes was altered up to fourteen-fold levels in SK-BR-3 cell lines whereas it reached 2.5-fold in the MCF-12A cell line after treatment with VA. These observations support that VA induces apoptosis on the breast cancer cells compared with the non-cancerous human breast epithelial cell line. Conclusion: It is implicated that VA may be a promising novel molecule for the induction of apoptosis on breast cancer cells.

Background and Objectives: Aldose Reductase (AR), a polyol pathway enzyme that mediates diabetic complications is implicated in tumour development and progression. This study was undertaken to determine whether gedunin, a neem limonoid prevents the hallmarks of cancer by inhibiting AR and the associated downstream PI3K/Akt/mTOR/ERK/NF-ΚB signalling axis in the SCC131 oral cancer cell line. Methods: The expression of AR and key molecules involved in cell proliferation, apoptosis, autophagy, invasion and angiogenesis was analysed by qRT-PCR, and immunoblotting. ROS generation and cell cycle were analysed by FACS. Alamar blue assay and scratch assay were used to evaluate cell proliferation and migration in the endothelial cell line Eahy926. Results: Gedunin and the AR inhibitor epalrestat inhibited AR expression and ROS generation. Cell cycle arrest at G1/S was associated with cell death by autophagy with subsequent switch over to apoptosis. Furthermore, hypoxia-induced cell migration was inhibited in Eahy926 cells with downregulation of pro-invasive and proangiogenic proteins in SCC131 as well as Eahy926 cells. Co-inactivation of Akt and ERK was coupled with abrogation of IKK/NF-ΚB signaling. However, the combination of gedunin and epalrestat was more effective than single agents. Conclusion: Inhibition of AR-mediated ROS signalling may be a key mechanism by which gedunin and epalrestat exert their anticancer effects. Our results provide compelling evidence that the combination of gedunin and epalrestat modulates expression of key oncogenic signalling kinases and transcription factors primarily by influencing phosphorylation and subcellular localisation. AR inhibitors such as gedunin and epalrestat are novel candidate agents for cancer prevention and therapy.

Background: While Thioredoxin Reductase (TrxR) plays an important role in regulation of the intracellular redox balance and various signalling pathways, Glutathione S-Transferase (GSTs) enzymes belong to the detoxification family that catalyse the conjugation of glutathione with various endogenous and xenobiotic electrophiles. Since TrxR and GSTs are overexpressed in many cancer cells, they have been identified as potential targets to develop chemotherapeutic strategies. Method: The mitochondrial TrxR (TrxR2) enzyme and the cytosolic GST enzyme was purified from rat liver via affinity chromatography. After the purification, the in vitro inhibition effects of some anticancer drugs (cisplatin, calcium folinate, carboplatin, epirubicin hydrochloride, doxorubicin hydrochloride, paclitaxel, etoposide, fluorouracil, and methotrexate) were investigated on both enzymes. Since only methotrexate inhibits both enzymes among all the anticancer drugs, a molecular docking study was performed to determine the binding site and the binding affinity of methotrexate to the enzymes. Results: Firstly, TrxR2 and GST were found to have a specific activity of 0.436, 1765 EU/mg proteins with a yield of 39.20%, 31.28% and 207.6, 3516.6 of purification fold, respectively. While TrxR2 was strongly inhibited by all of the anticancer drugs, GST was not inhibited by any of the anticancer drugs except methotrexate. Conclusion: Both enzymes were inhibited by only methotrexate in rat liver, and methotrexate was well placed in the active sites of both proteins. Therefore, it may be argued that methotrexate may be a more effective anticancer drug than all other drugs used in this study against the multi drug resistance that will occur during chemotherapy.

Background: Lung cancer is one of the most leading causes of cancer-related deaths in adults worldwide. Non-Small Cell Lung Cancer (NSCLC), which comprises 80 to 85% of all lung cancers, is the most lethal subtype of lung cancer with a 5-year survival of less than 13%. In this study, we identified a poorly-studied kinase PDK4 as the most up-regulated kinase encoding gene in Cisplatin resistant lung adenocarcinoma. Methods: In vitro cell viability assay and in vivo tumor xenograft assay were used in the detection of cell proliferation. RNA isolation, quantitative Real-Time PCR, Western blot analysis, immunohistochemistry were used to investigate the expression of RNA and protein. Lentivirus infection was used to regulate gene expression. Luciferase assays were used to monitor EPAS1 promoter activity. Results: In vivo PDK4 expression was elevated in a Cisplatin-resistant population of lung adenocarcinoma cells, PDK4-dependent Cisplatin-resistance promotes tumor growth of lung adenocarcinoma in vivo and in vitro, clinically PDK4 expression was associated with poor prognosis in lung adenocarcinoma patients, mechanically PDK4 promoted cell growth and Cisplatin-resistance of lung adenocarcinoma via transcriptional regulation of endothelial PAS domain-containing protein 1 (EPAS1). Conclusion: PDK4 is the most up-regulated kinase encoding gene in Cisplatin resistant lung adenocarcinoma and PDK4-dependent Cisplatin-resistance promotes tumor growth of lung adenocarcinoma mainly through transcriptional regulation of EPAS1. Enriched PDK4 expression was correlated with the poor prognosis of lung cancer patients, indicating that PDK4 could be a potential therapeutic target for Cisplatin-resistant lung adenocarcinoma.