Anti-Cancer Agents in Medicinal Chemistry (Formerly Current Medicinal Chemistry - Anti-Cancer Agents) - Volume 21, Issue 1, 2021

Background: Angiogenesis is one of the critical physiological processes, by which the new blood vessels are generated from the pre-existing vessels in the early stage of vasculogenesis. While normal angiogenesis is critical for development and tissue growth, pathologic angiogenesis is important for the growth and spread of cancers by supplying nutrients and oxygen as well as providing a conduit for distant metastasis. In the last two decades, angiogenesis has been the area of extensive researches, indicating antiangiogenic target therapy as an effective strategy for cancer therapy. At present, this field has become a major avenue for research and development of novel therapeutics. Objective: This review is dedicated to an updated review of the most prominent antiangiogenic agents, emphasizing the novel advancements and their applications, in particular, in the fields of antibodies, peptides, vaccines, endogenous inhibitors, Nanoparticles (NPs), antiangiogenic oligonucleotides and small molecules. Also, the potential role of 3D microfluidic models as an affordable and time-saving tool for angiogenesis investigations are discussed. Methods: Firstly, we collected and summarized new developments that have occurred in all review and research articles in databases. Then, we used important keywords related to antiangiogenic target therapy and their applications for retrieval of most relevant data. Results: This review is based on recent research and review articles and intended to cover all newly discovered agents inhibiting tumor angiogenesis and in particular, VEGF. Conclusion: New research studies have shown that anti-angiogenesis agents especially, in the form of combination therapy are effective in various cancers treatment.

Background: The ubiquitin-proteasome pathway is involved in almost all cellular processes (cell cycle, gene transcription and translation, cell survival and apoptosis, cell metabolism and protein quality control) mainly through the specific degradation of the majority of intracellular proteins (>80%) or partial processing of transcription factors (e.g., NF-ΚB). A growing amount of evidence now indicates that epigenetic changes are also regulated by the ubiquitin-proteasome pathway. Recent studies indicate that epigenetic regulations are equally crucial for almost all biological processes as well as for pathological conditions such as tumorigenesis, as compared to non-epigenetic control mechanisms (i.e., genetic alterations or classical signal transduction pathways). Objective: Here, we reviewed the recent work highlighting the interaction of the ubiquitin-proteasome pathway components (e.g., ubiquitin, E1, E2 and E3 enzymes and 26S proteasome) with epigenetic regulators (histone deacetylases, histone acetyltransferases and DNA methyltransferases). Results: Alterations in the regulation of the ubiquitin-proteasome pathway have been discovered in many pathological conditions. For example, a 2- to 32-fold increase in proteasomal activity and/or subunits has been noted in primary breast cancer cells. Although proteasome inhibitors have been successfully applied in the treatment of hematological malignancies (e.g., multiple myeloma), the clinical efficacy of the proteasomal inhibition is limited in solid cancers. Interestingly, recent studies show that the ubiquitin-proteasome and epigenetic pathways intersect in a number of ways through the regulation of epigenetic marks (i.e., acetylation, methylation and ubiquitylation). Conclusion: It is therefore believed that novel treatment strategies involving new generation ubiquitinproteasome pathway inhibitors combined with DNA methyltransferase, histone deacetylase or histone acetyltransferase inhibitors may produce more effective results with fewer adverse effects in cancer treatment as compared to standard chemotherapeutics in hematological as well as solid cancers.

Background and Objective: Photoactive transition metal complexes like copper complexes find great interest in promoting metal-based photochemotherapeutic agents. In the present study, we explored the photocytotoxic efficacy of new selenylnaphthoquinone-based copper (II) complexes that provide a phenomenal platform in making an effective photo-chemotherapeutic agent via PDT in the clinical field of cancer therapy. Methods: Three new copper(II) complexes (1-3) were synthesized in 40-60% yield and characterized analytically/ spectroscopically. ATCC® Normal Adult Human Primary Epidermal Keratinocytes were grown in Dermal Cell Basal Media supplemented with Keratinocyte Growth Kit components, to propagate keratinocytes in serum- free (not animal free) conditions. Anticancer activity of the complexes was studied using MTT (3- [4,5- dimethyltiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) assay. The intracellular ROS (¹O2) generation was studied by using Flow Cytometric Analysis (FACS) on HaCaT cells using cell accessible non-polar 2′,7′- Dichlorofluorescein Diacetate (DCFH-DA) dye. The Acridine Orange/Ethidium Bromide (AO/EB) dual staining assay was performed for detecting apoptosis in HaCaT cells. Several photophysical studies probing the generation of singlet oxygen was also carried out. We have performed Time-Dependent Density Functional Theory (TD-DFT) calculations using unrestricted B3LYP to understand the mechanism of type-II process. Results: All the complexes were remarkably cytotoxic in HaCaT cells with IC50, 1-4μM under visible light with comparing lower dark toxicity. The presence of low-lying and long-lived triplet excited state allowed effective intersystem crossing and subsequent generation of singlet oxygen, which was the primary cytotoxic species responsible for oxidative stress and apoptosis. The experimental findings are in good agrrement with the computational analysis (TD-DFT). Conclusion: The remarkably enhanced cytotoxicity of the new selenyl copper (II) complexes under the visible light probed the role of Se in photosensitized generation of singlet oxygen which was responsible for apoptosis in HaCaT cells. The results in the present work are of paramount importance in developing next generation copper(II)-based PDT agents.

Background: The Epidermal Growth Factor Receptor (known as EGFR) induces cell differentiation and proliferation upon activation through the binding of its ligands. Since EGFR is thought to be involved in the development of cancer, the identification of new target inhibitors is the most viable approach, which recently gained momentum as a potential anticancer therapy. Objective: To assess various pyrazole linked pyrazoline derivatives with carbothioamide for EGFR kinase inhibitory as well as anti-proliferative activity against human cancer cell lines viz. A549 (non-small cell lung tumor), MCF-7 (breast cancer cell line), SiHa (cancerous tissues of the cervix uteri), and HCT-116 (colon cancer cell line). Methods: In vitro EGFR kinase assay, in vitro MTT assay, Lactate dehydrogenase release, nuclear staining (DAPI), and flow cytometry cell analysis. Results: Compounds 6h and 6j inhibited EGFR kinase at concentrations of 1.66μM and 1.9μM, respectively. Furthermore, compounds 6h and 6j showed the most potent anti-proliferative results against the A549 KRAS mutation cell line (IC50 = 9.3 & 10.2μM). Through DAPI staining and phase contrast microscopy, it was established that compounds 6h and 6j also induced apoptotic activity in A549 cells. This activity was further confirmed by FACS using Annexin-V-FITC and Propidium Iodide (PI) labeling. Molecular docking studies performed on 6h and 6j suggested that the compounds can bind to the hinge region of ATP binding site of EGFR tyrosine kinase in a similar pose as that of the standard drug gefitinib. Conclusion: The potential anticancer activity of compounds 6h and 6j was confirmed and need further exploration in cancer cell lines of different tissue origin and signaling pathways, as well as in animal models of cancer development.

Background: Periplogenin (PPG), a natural compound isolated from traditional Chinese herb Cortex Periplocae, has been reported to possess anti-inflammatory and anti-cancer properties. Objective: The present study aims to investigate the antitumor effects of PPG and the underlying mechanism in human colorectal cancer cells. Methods: The inhibition of cell growth in vitro was assessed by MTT assay. The induction of apoptosis and the ROS production induced by PPG was investigated by flow cytometry analysis. Western blotting was applied to measure the protein expression. Small interference RNA (siRNA) and a specific pharmacological inhibitor were used to knock down or inhibit the expression of related genes. Results: PPG was able to cause the production of ROS, inhibit the cancer cell growth and induce apoptosis. Nacetylcysteine was able to inhibit ROS production and apoptosis. PPG up-regulated the protein levels of BIP, peIF2α and CHOP as well as IRE1α and p-JNK, and down-regulated the protein level of p-ASK1, all of which were reversed by N-acetylcysteine. Importantly, knockdown of CHOP or JNK protein level attenuated the PPGelicited apoptosis. Conclusion: PPG-induced apoptosis was regulated by ROS-mediated BIP/eIF2α/CHOP and BIP/ASK1/JNK signaling pathways in colon cancer cells, suggesting that PPG is a promising therapeutic agent for the treatment of human colon cancer.

Background: At the present time, there is a growing interest in metal-based anticancer agents. Metal complexes exhibit many valuable clinical properties, however, due to toxicity, only a few clinically useful complexes have been discovered. It has been demonstrated that synthetic vanadium complexes exhibit many biological activities, including anti-cancer properties, however, cellular and molecular mechanisms still are not fully understood. Objective: This investigation examined the potential effects of three newly synthesized oxidovanadium(IV) complexes with 2-amino-3-hydroxypyridine against pancreatic cancer cells. Methods: We measured cytotoxicity by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, antiproliferative activity by bromodeoxyuridine assay and necrosis as well as late apoptosis by lactate dehydrogenase assay. Reactive oxygen species generation, apoptosis and mitochondrial membrane potential were determined by a flow cytometry technique. Cell morphology was evaluated by using a transmission electron microscope. Results: The results showed that oxidovanadium(IV) complexes were cytotoxic on pancreatic cancer cells (PANC-1 and MIA PaCa2) over the concentration range of 12.5-200μM, following 48h incubation. Additionally, the cellular mechanism of cytotoxic activity of [2-NH2-3-OH(py)H]4[V2O2(pmida)2]·6H2O (V3) complex was dependent on ROS generation, induction apoptosis with simultaneous disruption of mitochondrial membrane potential. Conclusion: We have proven that oxidovanadium (IV) complexes show therapeutic potential in pancreatic cancer therapy. The results of our research will help to understand the cellular mechanisms of the cytotoxic activity of the vanadium complexes and will allow a more effective design structure of new vanadium-based compounds in the future.

Background: 2(3H)-Benzoxazolone derivatives are preferential structural blocks in pharmacological probe designing with the possibility of modifications at various positions on the core structure. Benzoxazolones showed various biological activities such as analgesics, anti-inflammatory and anti-cancer. Objective: In the present work, we have prepared new Mannich bases of 2(3H)-benzoxazolone derivatives and evaluated their cytotoxicities and proapoptotic properties in MCF-7 breast cancer cell line. Methods: The structures of these compounds were characterized by FT-IR, elemental analysis, 1H and 13C NMR. Cytotoxicities of all the target compounds were investigated by MTT assay. Apoptotic properties of compounds were evaluated by immunocytochemistry using antibodies against caspase-3, cytochrome-c, FasL, and also TUNEL assay. Results: These two novel compounds, 1 and 2, both have the same piperazine substituent on the nitrogen atom of benzoxazolone and the main difference in the structures of these compounds is the presence of Cl substituent at the 5- position of the benzoxazolone ring. MTT results showed that compounds 1 and 2 were effective in terms of reduction of cell viability at 100μM and 50μM concentration for 48h, respectively. As a result of immunohistochemical staining, Fas L and caspase-3 immunoreactivities were significantly increased in MCF-7 cells after treatment with compound 1. Additionally, caspase-3 and cytochrome-c immunoreactivities were also increased significantly in MCF-7 cells after treatment with compound 2. The number of TUNEL positive cells was significantly higher in MCF-7 cells when compared with the control group after treatment with both compounds 1 and 2. Conclusion: It could be concluded that N-substituted benzoxazolone derivatives increase potential anti-cancer effects and they could be promising novel therapeutic agents for chemotherapy.

Background: Photodynamic Therapy (PDT) is a photoactivation or photosensitization process, wherein vitamin K3 (Vit K3) serves as a photosensitizer to produce Reactive Oxygen Species (ROS) against bacteria at appropriate wavelengths. In this study, we used Vit K3 treatment combined with Ultraviolet radiation A (UVA) to produce photodynamic effects on cervical cancer. Methods: The dose-concentration relationship between Vit K3 treatment and UVA on tumor cells was analyzed through the Cell Counting Kit-8 method. Then, the morphological characteristics of apoptosis cells were observed through fluorescent staining and fluorescence microscopy. Apoptosis after treatment with Vit K3 treatment, UVA, and Vit K3 treatment plus UVA was further observed through Western blot analysis, flow cytometry, and TUNEL assay. The xenograft models from HeLa cells were established for the exploration of the photodynamic effect of Vit K3 treatment on cervical cancer in vivo. Results: Vit K3 treatment plus UVA reduced tumor cell viability in a dose-dependent manner. Further studies indicated that Vit K3 treatment plus UVA can inhibit tumor growth and enhance the apoptosis of cervical cancer cells. In the combination group, the expression levels of cleaved caspase-3, cleaved caspase-9, B-cell lymphoma- extra large (Bcl-xl), and cytochrome c (cyt-c) increased obviously, whereas the expression level of Bcell lymphoma 2 (Bcl-2) decreased relative to the expression levels of UVA- or Vit K3-treated cells. In the in vivo experiments, tumor growth was inhibited significantly in the VitK3 treatment plus UVA group. Additionally, we demonstrated that the combination therapy mediated an increase in cleaved caspase-3 and cleaved caspase-9 expression and decrease in Bcl-2 expression in vivo. Conclusion: Our results showed that Vit K3 treatment combined with UVA exerted photodynamic effects on cervical cancer cells by activating mitochondrial apoptosis pathways.

Background: Esophageal Squamous-Cell Carcinoma (ESCC) is one of the most life-threatening malignancies worldwide, with a growing incidence in Iran higher than the global average. Objective: The present study, for the first time under patent number (97668), introduces a method using in vitro production of activated-Birch stem cells using biotechnological techniques of tissue culture and plant stem cell culture from Betula pendula Roth (Birch) bark. Methods: In the first step, Birch stem cells were produced in large amounts using tissue culture, and then the amount of triterpenoids of its extract was measured by the HPLC method. In the second step, the cytotoxicity was evaluated by MTT, and the IC50 was calculated. The cellular apoptosis in response to the extract compared to doxorubicin was measured using the Annexin V kit and the flow cytometry method. Results: The optimized method introduced in the current study efficiently produced plant stem cells containing triterpenoids in large quantities over a period of 2-4 months. Our findings indicated that the growth of ESCC cells decreased by induction treatment 3 times (24, 36, 48 hours). IC50 values were obtained in 24 hours for the natural bark extract, Birch stem cell extract, doxorubicin and interactions of two extracts with doxorubicin at 300μg/mL, 1700μg/mL, 0.5μM, 150μg/mL, 1800μg/mL, respectively. In the flow cytometric test, the Birch stem cell extract showed the highest percentage of apoptosis, with 92.5% for total apoptosis. The percentage of total apoptosis in doxorubicin treatment was 85.33%, and the combination of doxorubicin with Birch stem cell extract was 88.33%. Natural bark extract and its combination with a lower percentage (69.33% and 70.33%, respectively) caused apoptosis of esophageal cancer cells. Conclusion: Owing to the extinction of Birch in Iran and its inaccessibility and exploitation, Birch stem cells can be cultured as an appropriate alternative source to produce valuable triterpenoids for pharmaceutical purposes. Additionally, according to the results of this study, stem cells can be used to enhance the treatment of esophageal cancer and supplementation with chemotherapy.

Background: The intertwining between cancer pathogenesis and aberrant expression of either oncogenes or tumor suppressor proteins ushered the cancer therapeutic approaches into a limitless road of modern therapies. For the nonce and among the plethora of promising anticancer agents, intense interest has focused on pioglitazone, a first in-class of Thiazolidinedione (TZD) drugs that is currently used to treat patients with diabetes. Objective: Intrigued by the overexpression of PPARγ in Acute Promylocytic Leukemia (APL), this study was designed to investigate the effects of pioglitazone in APL-derived NB4 cells. Methods: To assess the anti-leukemic effect of pioglitazone on myeloid leukemia cell lines, we used MTT and trypan blue assays. Given the higher expression level of PPARγ in NB4 cells, we then expanded our experiments on this cell line. To ascertain the molecular mechanism action of pioglitazone in APL-derived NB4 cells, we evaluated the expression levels of a large cohort of target genes responsible for the regulation of apoptosis, autophagy and cell proliferation. Afterward, to examine whether there is a correlation between PPARγ and the PI3K signaling pathway, the amount of Akt phosphorylation was evaluated using western blot analysis. Results: Our results showed that pioglitazone exerted its cytotoxic effect in wild-type PTEN-expressing NB4 cells, but not in leukemic K562 cells harboring mutant PTEN; suggesting that probably this member of TZD drugs induced its anti-leukemic effects through a PTEN-mediated manner. Moreover, we found that not only pioglitazone reduced the survival rate of NB4 through the induction of p21-mediated G1 arrest, also elevated the intracellular level of Reactive Oxygen Species (ROS) which was coupled with upregulated FOXO3a. Notably, this study proposed for the first time that the stimulation of autophagy as a result of the compensatory activation of PI3K pathway may act as a plausible mechanism through which the anti-leukemic effect of pioglitazone may be attenuated; suggestive of the application of either PI3K or autophagy inhibitors along with pioglitazone in APL. Conclusion: By suggesting a mechanistic pathway, the results of the present study shed more light on the favorable anti-leukemic effect of pioglitazone and suggest it as a promising drug that should be clinically investigated in APL patients.