Novel phenylenediamine bridged mixed ligands dimetallic square planner Pt(II) complex inhibits MMPs expression via p53 and caspase-dependent signaling and suppress cancer metastasis and invasion

DNA or not DNA -that is the question determining the design of platinum anticancer drugs

Platinum drugs are the most widely used chemotherapeutics to treat various tumors. Their primary mode of action is supposed to be inducing apoptosis of cancer cells via covalent binding to DNA. This mechanism has shackled the design of new platinum drugs for many years. Mounting evidence shows that many platinum complexes form non-covalent adducts with DNA or interact with proteins to exhibit significant antitumor activity, thus implying some distinct mechanisms from that of traditional platinum drugs. These unconventional examples indicate that covalent DNA binding is not the precondition for the antitumor activity of platinum complexes, and diversified reactions or interactions with biomolecules, organelles, signal pathways, or immune system could lead to the antitumor activity of platinum complexes. The atypical mechanisms break the classical DNA-only paradigm and structure-activity relationships, thus opening a wide avenue for the design of innovative platinum anticancer drugs.

Metal Complexes as Promising Matrix Metalloproteinases Regulators

Nowadays, cancers and dementia, such as Alzheimer's disease, are the most fatal causes of death. Many studies tried to understand the pathogenesis of those diseases clearly and develop a promising way to treat the diseases. Matrix metalloproteinases (MMPs) have been reported to be involved in the pathology of cancers and AD through tumor cell movement and amyloid degradation. Therefore, control of the levels and actions of MMPs, especially MMP-2 and MMP-9, is necessary to care for and/or cure cancer and AD. Various molecules have been examined for their potential application as regulators of MMPs expression and activity. Among the molecules, multiple metal complexes have shown advantages, including simple synthesis, less toxicity and specificity toward MMPs in cancer cells or in the brain. In this review, we summarize the recent studies and knowledge of metal complexes (e.g., Pt-, Ru-, Au-, Fe-, Cu-, Ni-, Zn-, and Sn-complexes) targeting MMPs and their potentials for treating and/or caring the most fatal human diseases, cancers and AD.

PPARγ signaling in hepatocarcinogenesis: Mechanistic insights for cellular reprogramming and therapeutic implications

Liver cancer or hepatocellular carcinoma (HCC) is leading cause of cancer-related mortalities globally. The therapeutic approaches for chronic liver diseases-associated liver cancers aimed at modulating immune check-points and peroxisome proliferator-activated receptor gamma (PPARγ) signaling pathway during multistep process of hepatocarcinogenesis that played a dispensable role in immunopathogenesis and outcomes of disease. Herein, the review highlights PPARγ-induced effects in balancing inflammatory (tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, IL-1) and anti-inflammatory cytokines (IL-10, transforming growth factor beta (TGF-β), and interplay of PPARγ, hepatic stellate cells and fibrogenic niche in cell-intrinsic and -extrinsic crosstalk of hepatocarcinogenesis. PPARγ-mediated effects in pre-malignant microenvironment promote growth arrest, cell senescence and cell clearance in liver cancer pathophysiology. Furthermore, PPARγ-immune cell axis of liver microenvironment exhibits an immunomodulation strategy of resident immune cells of the liver (macrophages, natural killer cells, and dendritic cells) in concomitance with current clinical guidelines of the European Association for Study of Liver Diseases (EASL) for several liver diseases. Thus, mechanistic insights of PPARγ-associated high value targets and canonical signaling suggest PPARγ as a possible therapeutic target in reprogramming of hepatocarcinogenesis to decrease burden of liver cancers, worldwide.

Vitamin B6 based Pt(II) complexes: Biomolecule derived potential cytotoxic agents for thyroid cancer

Vitamin B6 is an essential vitamin that serves as a co-enzyme in a number of enzymatic reactions in metabolism of lipids, amino acids and glucose. In the current study, we synthesized vitamin B6 derived ligand (L) and its complex Pt(L)Cl (C1). The ancillary chloride ligand of C1 was exchanged with pyridine co-ligand and another complex Pt(L)(py).BF4 (C2) was obtained. Both these complexes were obtained in excellent isolated yields and characterized thoroughly by different analytical methods. Thyroid cancer is one of the most common malignancies of the endocrine system, we studied the in vitro anticancer activity and mechanism of these vitamin B6 derived L and Pt(II) complexes in thyroid cancer cell line (FTC). Based on MTT assay, cell proliferation rate was reduced in a dose-dependent manner. According to apoptosis analysis, vitamin B6 based Pt(II) complexes treated cells depicted necrotic effect and TUNEL based apoptosis was observed in cancer cells. Furthermore, qRT-PCR analyses of cancer cells treated with C1 and/or C2 showed regulated expression of anti-apoptotic, pro-apoptosis and autophagy related genes. Western blot results demonstrated that C1 and C2 induced the activation of p53 and the cleavage of Poly (ADP-ribose) polymerase (PARP). These results suggest that these complexes inhibit the growth of FTC cells and induce apoptosis through p53 signaling. Thus, vitamin B6 derived Pt(II) complexes C1 and C2 may be potential cytotoxic agents for the treatment of thyroid cancer.

Inhibition of SREBP-mediated lipid biosynthesis and activation of multiple anticancer mechanisms by platinum complexes: Ascribe possibilities of new antitumor strategies

Cancer is one of the most aggressive diseases with poor prognosis and survival rates. Lipids biogenesis play key role in cancer progression, metastasis and tumor development. Suppression of SREBP-mediated lipid biogenesis pathway has been linked with cancer inhibition. Platinum complexes bearing good anticancer effect and multiple genes activation properties are considered important and increase the chances for development of new platinum-based drugs. In this study, we synthesized pyridine co-ligand functionalized cationic complexes and characterized them using multiple spectroscopic and spectrophotometric methods. Two of these complexes were studied in solid state by single crystal X-ray analysis. The stability of these complexes were measured in solution state using ¹H NMR methods. These complexes were further investigated for their anticancer activity against human breast, lung and liver cancer cells. MTT assay showed potential cytotoxic activity in dose-dependent manner and decrease survival rates of cancer cells was observed upon treatment with these complexes. Biological assays results revealed higher cytotoxicity as compared to cisplatin and oxaliplatin. Further we studied C2, C6 and C8 in detailed mechanistic anticancer analyses. Clonogenic assay showed decrease survival of MCF-7, HepG2 and A549 cancer cells treated with C2, C6 and C8 as compared to control cells treated with DMSO. TUNEL assay showed more cell death, these complexes suppressed invasion and migration ability of cancer cells and decreased tumor spheroids formation, thus suggesting a potential role in inhibition of cancer metastasis and cancer stem cells formation. Mechanistically, these complexes inhibited sterol regulatory element-binding protein 1 (SREBP-1) expression in cancer cells in dose-dependent manner and thereby reduced lipid biogenesis to suppress cancer progression. Furthermore, expression level was decreased for the key genes LDLR, FASN and HMGCR, those required for sterol biosynthesis. Taken together, these complexes suppressed cancer cell growth, migration, invasion and spheroids formation by inhibiting SREBP-1 mediated lipid biogenesis pathway.

Cancer‑associated fibroblast‑derived LRRC15 promotes the migration and invasion of triple‑negative breast cancer cells via Wnt/β‑catenin signalling pathway regulation

Triple-negative breast cancer (TNBC) is a highly aggressive tumour subtype associated with poor prognosis. The function of leucine-rich repeat-containing protein 15 (LRRC15), a member of the leucine-rich repeat superfamily, in TNBC has not yet been elucidated. The aim of this study was to identify the combined role of LRRC15 and Wnt/β-catenin signalling pathway in the development of TNBC. The expression of LRRC15 in TNBC tissues was analysed using data from The Cancer Genome Atlas. Cell migration and invasion assays were conducted to study the function of LRRC15 in TNBC. The expression of Wnt/β-catenin signalling proteins was analysed via western blotting. The effect of LRRC15 on β-catenin nuclear localisation was measured by performing western blotting and luciferase assays. It was found that high LRRC15 expression was associated with poor prognosis in patients with TNBC. High expression of LRRC15 in cancer-associated fibroblasts (CAFs) promoted cell migration and invasion in TNBC cells. In addition, TNBC cells with LRRC15 overexpression in CAFs showed an aberrant increase in β-catenin activity concomitant with nuclear localisation of β-catenin, which inhibited its degradation. These results showed that LRRC15 promoted tumour migration and invasion in TNBC cells by regulating the Wnt/β-catenin signalling pathway.

Influence of Tumor Suppressor p53 Functioning on the Expression of Antioxidant System Genes under the Action of Cytotoxic Compounds

The effect of inhibition of the tumor suppressor p53 on the antioxidant system genes expression under the influence of cytotoxic compounds of the platinum group was studied. It was found that the action of platinum(II) and platinum(IV) complexes induced accumulation of p53 protein with a maximum in 12 h, which was confirmed by an increase in the expression of the P21 gene, the target gene of the p53 protein. It was shown that the action of platinum complexes activated the expression of catalase and superoxide dismutase 2 genes. Suppression of p53 protein functions with specific inhibitor α-piphitrin under the action of platinum complexes reduced the expression of catalase and superoxide dismutase 2 genes and the target gene P21, which attested to the p53-dependent regulation of these genes.

Anticancer activity and mechanism of bis-pyrimidine based dimetallic Ru(II)(η6-p-cymene) complex in human non-small cell lung cancer via p53-dependent pathway

Non-small cell lung cancer (NSCLC) is the most common cancer worldwide, which is related with poor prognosis and resistance to chemotherapy. Notably, ruthenium-based complexes have emerged as good alternative to the currently used platinum-based drugs for cancer therapy. In the present study, we synthesized a novel bis-pyrimidine based ligand 1,3-bis(2-methyl-6-(pyridin-2-yl)pyrimidin-4-yl)benzene (L) and used it in the synthesis of a dimetallic Ru(II) cymene complex [(Ru(η⁶-p-cymene)Cl)₂(1,3-bis(2-methyl-6-(pyridin-2-yl)pyrimidin-4-yl)benzene)] (L-Ru). We checked the stability of this complex in solution state in D₂O/DMSO‑d₆ mixture and found it to be highly stable under these conditions. We determined the anticancer activity and mechanism of action of L-Ru in human NSCLC A549 and A427 by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and related biological analyses. These results revealed that L-Ru exerted a strong inhibitory effect on the cells proliferation,G0/G1-arrest, accompanied with upregulation of p53, p21, p15, cleaved Poly (ADP-ribose) polymerase (PARP) protein and downregulation of cell cycle markers. L-Ru inhibited cell migration and invasion. The mitochondria-mediated apoptosis of NSCLC induced by L-Ru was also observed followed by the increase of apoptosis regulator B-cell lymphoma 2 associated X (BAX), and activation of caspase-3/-9. The effects of L-Ru on the cell viability, Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive cells and Annexin V-positive cells apoptosis induction were remarkably attenuated. This complex induced DNA damage, cell cycle arrest and cell death via caspase-dependent apoptosis involving PARP activation and induction of p53-dependent pathway. These findings suggested that this ruthenium complex might be a potential effective chemotherapeutic agent in NSCLC therapy.

Toward Multi-Targeted Platinum and Ruthenium Drugs-A New Paradigm in Cancer Drug Treatment Regimens?

While medicinal inorganic chemistry has been practised for over 5000 years, it was not until the late 1800s when Alfred Werner published his ground-breaking research on coordination chemistry that we began to truly understand the nature of the coordination bond and the structures and stereochemistries of metal complexes. We can now readily manipulate and fine-tune their properties. This had led to a multitude of complexes with wide-ranging biomedical applications. This review will focus on the use and potential of metal complexes as important therapeutic agents for the treatment of cancer. With major advances in technologies and a deeper understanding of the human genome, we are now in a strong position to more fully understand carcinogenesis at a molecular level. We can now also rationally design and develop drug molecules that can either selectively enhance or disrupt key biological processes and, in doing so, optimize their therapeutic potential. This has heralded a new era in drug design in which we are moving from a single- toward a multitargeted approach. This approach lies at the very heart of medicinal inorganic chemistry. In this review, we have endeavored to showcase how a "multitargeted" approach to drug design has led to new families of metallodrugs which may not only reduce systemic toxicities associated with modern day chemotherapeutics but also address resistance issues that are plaguing many chemotherapeutic regimens. We have focused our attention on metallodrugs incorporating platinum and ruthenium ions given that complexes containing these metal ions are already in clinical use or have advanced to clinical trials as anticancer agents. The "multitargeted" complexes described herein not only target DNA but also contain either vectors to enable them to target cancer cells selectively and/or moieties that target enzymes, peptides, and intracellular proteins. Multitargeted complexes which have been designed to target the mitochondria or complexes inspired by natural product activity are also described. A summary of advances in this field over the past decade or so will be provided.

Discovery of dehydroabietic acid sulfonamide based derivatives as selective matrix metalloproteinases inactivators that inhibit cell migration and proliferation

A series of dehydroabietic acid (DHAA) dipeptide derivatives containing the sulfonamide moiety were designed, synthesized and evaluated for inhibition of MMPs as well as the effects of in vitro cell migration. These compounds exhibited relatively good inhibition activity against MMPs with IC₅₀ values in low micromolar range. A docking study of the most active compound 8k revealed key interactions between 8k and MMP-3 in which the sulfonamide moiety and the dipeptide group were important for improving activity. It is noteworthy that further antitumor activity screening revealed that some compounds exhibited better inhibitory activity than the commercial anticancer drug 5-FU. In particular, compound 8k appeared to be the most potent compound against the HepG2 cell line, at least partly, by inhibition of the activity of MMP-3 and apoptosis induction. The treatment of HepG2 cells with compound 8k resulted in inhibition of in vitro cell migration through wound healing assay and G1 phase of cell cycle arrested. In addition, 8k-induced apoptosis was significantly facilitated in HepG2 cells. Thus, we conclude that DHAA dipeptide derivatives containing the sulfonamide moiety may be the potential MMPs inhibitors with the ability to suppress cells migration.