Anti-Cancer Agents in Medicinal Chemistry (Formerly Current Medicinal Chemistry - Anti-Cancer Agents) - Volume 23, Issue 3, 2023

Acute myeloid leukemia (AML) is a malignant disorder characterized by myeloid differentiation arrest and uncontrolled clonal expansion of abnormal myeloid progenitor cells. AML is the most common malignant bone marrow (BM) disease in adults and accounts for approximately 80% of adult leukemia cases. There has been little improvement in the treatment of patients with AML over the past decade. Cytogenetic and morphologic heterogeneity of AML and the difficulty in distinguishing leukemic stem cells (LSCs) from normal hematopoietic stem cells (HSCs) continue to be the major challenges in treating this malignancy. In recent years, intensive efforts have been made to explore novel potential markers for the efficient identification and characterization of leukemic stem cells. Aldehyde dehydrogenase (ALDH) is a potential target molecule that plays crucial roles in leukemic stem cell survival and multidrug resistance, mainly through its involvement in the detoxification of many endogenous and exogenous aldehydes. The selection and isolation of cancer stem cells based on high ALDH activity seem to be a useful approach in many human malignancies, especially leukemia. Moreover, it is worth mentioning that several previous studies have indicated that a high ALDH activity (classified as ALDHbr cells in flow cytometry) can act as an independent prognostic factor in several types of cancer. In the present review, we update and critically discuss the available data regarding the importance of ALDH activity in normal and leukemic stem cells and its potential diagnostic and therapeutic implications.

Background: Peptidyl arginine deiminase IV (PADI4, also called PAD4), a Ca²⁺-dependent posttranslational modification enzyme, catalyzes the conversion of arginine residues to non-coded citrulline residues. Dysregulation of PADI4 is involved in a variety of diseases including rheumatoid arthritis (RA), multiple sclerosis (MS), Alzheimer's disease (AD) and many kinds of malignant tumors. Objective: The roles of PADI4 in different tumors and the underlying molecular mechanisms are presented in this article. Results: PADI4-mediated citrullination is associated with either transcriptional activation or repression in different contexts. Abnormal expression of PADI4 exists in a variety of malignant tumors and affects tumor progression and metastasis. Epithelial-to-mesenchymal transition (EMT), apoptosis, and neutrophil extracellular traps (NETs) may be the underlying molecular mechanisms. Conclusion: PADI4 plays crucial role in the occurrence, development, and metastasis of tumors, and PADI4 may be an effective biomarker for cancer prognosis and a potential target for cancer treatment.

The interactions and secretions within the tumour have a pivotal role in tumour growth and therapy. Immunosuppressive cells such as regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), tumour-associated macrophages (TAMs), and cancer-associated fibroblasts (CAFs) secrete some substances, which can result in the exhaustion of anti-tumour immunity. To stimulate anti-tumour immunity, suppression of the secretion and interactions of immunosuppressive cells, on the other hand, stimulation of proliferation and activation of natural killer (NK) cells and CD8+ T lymphocytes are required. Apigenin is a flavone with anticancer properties. Emerging evidence shows that not only does apigenin modulate cell death pathways in cancer cells but it also can stimulate anti-tumour immune cells to release death signals and suppress the release of tumour-promoting molecules. In this review, we discuss the interactions between apigenin and various cells within the tumour microenvironment (TME). These interactions may enhance anti-tumour immunity to improve the efficiency of anticancer remedies such as immunotherapy.

Melanomas represent only 4% of all skin cancers, but their mortality rate is more than 50 % of any other skin cancer. Alteration in genetic and environmental factors are the risk factors for melanoma development. The RAS/RAF/MEK/ERK or Mitogen-activated protein kinase (MAPK) pathway is activated in melanoma. BRAF activation is necessary to govern differentiation, proliferation, and survival. Mutations in BRAF were found in 80–90% of all melanomas. Over 90% of BRAF mutations occur at codon 600, and over 90% of them are BRAFV600E other common mutations are BRAFV600K, BRAFV600R, BRAF V600′E2′, and BRAF V600D. Based on αC-helix and DFG motif (αC-helix-IN/DFG-IN), (αC-helix-IN/DFG-OUT), (αC-helix-OUT/DFG-IN) and (αC-helix-OUT/ DFG-OUT) are four structural types of inhibitors for targeting BRAF. Sorafenib, Vemurafenib, Dabrafenib, and Encorafenib are FDAapproved for the treatment of BRAF. Understanding melanoma pathogenesis, RAS/RAF/MEK/ERK or MAPK pathway, and BRAF conformations, mutations, the problems with FDA approved BRAF inhibitors will be important for new drug discovery, modification of existing BRAF barriers to improve target specific action, and prevent increasing response levels while minimizing toxicity.

Background: Due to their primary effects on DNA synthesis, antimetabolites are most effective against actively dividing cells and are significantly specific to the cell cycle phase. Pralatrexate (PDX), an antifolate metabolite designed to accumulate in cancer cells, was the first new agent approved by the US Food and Drug Administration for the treatment of resistant/recurrent peripheral T-cell lymphomas. PDX was a drug that is frequently used not only for PTCL, but also for cutaneous T-cell lymphoma (CTCL), extranodal natural killer (NK) / T-cell lymphoma. Objective: This article reviews Pralatrexate's history, pharmacokinetics, clinical phase studies including phases I, II and III, types of cancers it is effective on, drug side effects, inhibition mechanism and even its use in the treatment of other cancers with innovative methods, including its antiviral effect against SARS-CoV-2 infection. Methods: A comprehensive internet-based research was planned, covering all published and unpublished studies on the subject. We conducted this review in accordance with Preferred Reporting Items for systematic reviews and metaanalysis (PRISMA-P), and Cochrane Collaboration reporting items for systematic reviews and meta-analysis. The results of the studies in the articles were recorded to include all phase studies. Results: Pralatrexate was structurally designed to have enhanced cellular transport via RFC (reduced folate carrier type) and be subject to more polyglutamation compared to methotrexate. The enhanced polyglutamylation ability of pralatrexate is associated with increased tumor cell death and ultimately improved anticancer activity. Pralatrexate is considered a promising drug for patients with recurrent and treatment-resistant PTCL with a good survival advantage. At the same time, it is an antifolate agent with a significant advantage over methotrexate as it does not cause myelosuppression. Conclusion: While there are manageable side effects such as thrombocytopenia, neutropenia, and mucositis, it is critical to explore new approaches, targeted agents, novel cellular therapies, and immunotherapies to determine optimal pretreatment in the rare but heterogeneous disease PTCL, and future studies and experienced haematologists are needed.

Aim: The main aim of this study is to improve the solubility, reduce side effects and increase the therapeutic efficacy of CSL by using functionalized graphene oxide as a carrier, to fulfill chemo-photothermal therapy. Background: Celastrol (CSL), which is extracted from the traditional Chinese medicinal plant Tripterygium wilfordii, has reported significant antitumor activity in vitro and in vivo cancer models. However, disadvantages with regard to solubility, short plasma half-life and toxicity hinder its use in pharmaceutical application. Nanocarrier delivery system could be employed to improve the biochemical and pharmacokinetic performance of CSL. Among numerous nanocarriers, graphene oxide is one of the most promising nanocarriers due to its intrinsic physical and chemical properties and good biocompatibility. Objective: Here, we employed a PEGylated reduced nanographene oxide CSL complex (nrGO-PEG/CSL) as a new drug delivery system to achieve highly efficient synergistic chemo/photothermal therapy. Methods: A functionalized nrGO-PEG was synthesized and the loading capacity of CSL, photothermal effect and release efficiency under different pH and NIR irradiation were measured in the first stage of work. In vitro and in vivo anticancer effects of prepared nrGO-PEG/CSL complex were evaluated on 4T1 cells and 4T1 tumor-bearing mice, respectively, with the association of NIR laser irradiation. Results: The functionalized nrGO-PEG exhibited excellent drug loading capacity of CSL (20.76 mg/mg GO) and photothermal effect (∼3.0 -fold increment over unreduced nGO-PEG). Loaded CSL could be efficiently released from nrGO-PEG/CSL complex by NIR irradiation in vitro. In vivo study performed on 4T1 tumor-bearing mice proved that nrGO-PEG/CSL with NIR laser irradiation shows superior anticancer effects. Conclusion: The experimental data demonstrated that the nrGO-PEG/CSL-mediated chemo/photothermal combination therapy was more cytotoxic to cancer cells than only chemotherapy or photothermal treatment, reducing the occurrence of tumor metastasis. Therefore, nrGO-PEG/CSL-mediated chemo/photothermal is expected to be a promising treatment for synergistic cancer therapy.

Objective: Peimine (PM) is a bioactive compound obtained from Fritillaria. It has been documented that PM exhibits potent antitumor properties against multiple cancers. However, the antitumor properties of PM in breast cancer and its associated mechanisms have not been clarified. Methods: Proliferation and apoptosis of MCF-7 and MCF-10A cells were detected by CCK8, colony formation, and flow cytometry assays. Cytotoxicity was measured by Lactate dehydrogenase (LDH) leakage assay. The level of IL-1β and IL-18 were detected with ELISA kits. Western blotting and real-time Polymerase Chain Reaction were performed to analyze the expression of proteins and genes related to the NLRP3 inflammasome pathway and Endoplasmic reticulum stress. Results: The doses of PM (5, 10, and 20 μM) inhibited cell viability significantly, apoptotic induction, and inflammasome activation in breast cancer cells in vitro. Inflammasome components were decreased, including the apoptosisassociated speck like protein containing a CARD (ASC) and NOD-like receptor pyrindomain-containing protein3 (NLRP3), as well as the inhibition of caspase-1 and interleukin-1β activation. Moreover, inflammasome inhibitors suppressed cell growth and induced apoptosis, implying that PM suppresses the growth of breast cancer cells through regulating inflammasome. Mechanistically, PM inhibited the activity of inflammasome by alleviating endoplasmic reticulum (ER) stress and by down-regulating the expression of multiple proteins in transcription factor nuclear factor- ΚB (NF-ΚB) and mitogen-activated protein kinases (MAPKs) signaling pathways. Conclusion: These findings show that PM suppresses the growth of breast cancer cells by inhibiting inflammasome activation, to a certain extent, by primarily acting on the MAPK/NF-ΚB pathway's inactivation-dependent mechanisms.

Background: Some heterocycles having bisamide linkage are receiving much interest due to their remarkable biological potencies and they are naturally occurring. Some bisamides and thiazole derivatives were found to inhibit the protein levels of Bcl-2 significantly. This prompted us to synthesize new bis(heterocyclic) derivatives having bisamide function to explore their anti-cancer activities. Methods: Novel bis-amide-based bis-thiazoles and thiadiazoles were synthesized by reaction of a new bisthiosemicarbazone with a variety of hydrazonoyl chlorides, a-chloroacetylacetone and haloacetic acid derivatives. Most of the synthesized derivatives were tested for colorectal (HCT-116) and breast (MCF-7) cell lines using the MTT assay, with the apoptotic investigation through flow cytometric and RT-PCR analyses. Results: Some derivatives were found to be highly cytotoxic against HCT-116 cells with an IC50 range of (10.44-13.76 μM) compared to 5-fluorouracil (5-FU) (IC50 = 11.78 μM). One product significantly stimulated apoptotic colorectal cancer cell death by 27.24-fold (50.13% compared to control 1.84%) by arresting the cell cycle at the G2/M phase. The obtained results revealed that compound 7f was more cytotoxic against HCT-116 cells than 5-FU. Compound 7f remarkably enhanced apoptotic colorectal cancer cell death and upregulated the propapoptotic genes (P53, BAX and Capases-3,-8,-9) and downregulated the anti-apoptotic gene, B-cell lymphoma 2 (Bcl-2). In vivo study exhibited that 7f-treatment caused tumor inhibition ratio (TIR%) of 50.45% compared to 54.86% in the 5-FU treatment, with a significant reduction in tumor mass and volume. The anti-tumor activity of compound 7f was accompanied by ameliorated hematological and biochemical analyses, histopathological improvement in treated liver tissues, and the immunohistochemical staining revealed Bcl-2 inhibition in agreement with the in vitro results. Conclusion: Compound 7f is an interesting candidate for further development as a chemotherapeutic anti-cancer agent.

Background: The significant increase in patients suffering from different types of cancer, guides scientists to take prompt measures in the development of novel and effective antiproliferative agents, where the intercalation of heterocyclic fragments in the designed molecules has proven to be a useful practice. Objective: The newly synthesized compounds were obtained from the corresponding 1,4-dicarbonyl derivative through multicomponent reactions to produce biologically active target molecules and assessed by in silico and in vitro assays for their possible antitumor activity. Methods: The pharmacological bioassay was conducted in the panel of human tumor cell lines (i) SKW-3 (ACC 53) – human T-cell leukemia and (ii) HL-60 (ACC 3) - human acute myeloid leukemia (AML). The statistical processing of MTT data included the paired Student’s t-test with p ≤ 0.05 set as significance level. Results: All evaluated structures displayed a higher cytotoxic effect against the acute myeloid leukemia HL-60 with 11o and 11p as the most active compared to the activity against SKW-3 cell line. Throughout the cytotoxicity screening two molecules, 11l and 12o, displayed comparable chemosensitivity on both cell lines. The corresponding hepatotoxicity on isolated rat hepatocytes and microsomes was also established, identifying 11, 12 and 12a as the least toxic and 11x, 11d, 12x and 12d as the most toxic derivatives. Conclusion: As the most promising compound is underlined ethyl 1-(2-(2-((1-acetyl-1H-indol-3-yl)methylene)hydrazinyl)-2- oxoethyl)-5-(4-bromophenyl)-2-methyl-1H-pyrrole-3-carboxylate (11l) demonstrating highest activity on both evaluated tumor cell lines, decreased hepatotoxicity on all evaluated parameters and docking score of -7.517 kcal/mol.

Background: C-KIT is a receptor tyrosine kinase with oncogenic properties overexpressed in PCa cases. Through the use of an alternative promoter, a truncated c-KIT protein (tr-KIT) of 30-50 kDa is generated, lacking the extracellular and transmembrane domain. Tr-KIT promotes the formation of a multi-molecular complex composed of Fyn, Plcγ1, and Sam68. Imatinib blocks the activity of full-length c-KIT but has no effect on tr-KIT. LNCaP is the human PCa cell line that shows tr-KIT overexpression and PC3 does not show tr-KIT overexpression. miR-128/193a- 5p/494 are miRNAs targeting FYN, PLCγ1, and SAM68 combinatorially. The study's question is: can miR-128/193a- 5p/494 be related to imatinib resistance in PCa? Methods: LNCaP and PC3 cells were treated with imatinib in IC50 doses. Before and after imatinib administration, RNA was isolated and cDNA conversion was performed. By qPCR analysis, expression changes of tr-KIT specific pathway elements and miR-128/193a-5p/494 were analyzed before and after imatinib administration. Results: After imatinib administration, miR-128/193a-5p/494 were significantly overexpressed in LNCaP cells while downregulated significantly in PC3 cells (p<0.05). Also, FYN was upregulated in LNCaP cells (p<0.05) but there was no change in PC3 after imatinib administration. Conclusion: Especially upregulation of FYN may sponge miR128/193a-5p/494 and downregulate their transcriptional activity in LNCaP cells having tr-KIT activity. So, miR-128/193a-5p/494 may have a critical role in imatinib resistance via a tr-KIT pathway.