Role of transporters in the distribution of platinum-based drugs

Interaction of the New Monofunctional Anticancer Agent Phenanthriplatin With Transporters for Organic Cations

Cancer treatment with platinum compounds is an important achievement of modern chemotherapy. However, despite the beneficial effects, the clinical impact of these agents is hampered by the development of drug resistance as well as dose-limiting side effects. The efficacy but also side effects of platinum complexes can be mediated by uptake through plasma membrane transporters. In the kidneys, plasma membrane transporters are involved in their secretion into the urine. Renal secretion is accomplished by uptake from the blood into the proximal tubules cells, followed by excretion into the urine. The uptake process is mediated mainly by organic cation transporters (OCT), which are expressed in the basolateral domain of the plasma membrane facing the blood. The excretion of platinum into the urine is mediated by exchange with protons via multidrug and toxin extrusion proteins (MATE) expressed in the apical domain of plasma membrane. Recently, the monofunctional, cationic platinum agent phenanthriplatin, which is able to escape common cellular resistance mechanisms, has been synthesized and investigated. In the present study, the interaction of phenanthriplatin with transporters for organic cations has been evaluated. Phenanthriplatin is a high affinity substrate for OCT2, but has a lower apparent affinity for MATEs. The presence of these transporters increased cytotoxicity of phenanthriplatin. Therefore, phenanthriplatin may be especially effective in the treatment of cancers that express OCTs, such as colon cancer cells. However, the interaction of phenanthriplatin with OCTs suggests that its use as chemotherapeutic agent may be complicated by OCT-mediated toxicity. Unlike cisplatin, phenanthriplatin interacts with high specificity with hMATE1 and hMATE2K in addition to hOCT2. This interaction may facilitate its efflux from the cells and thereby decrease overall efficacy and/or toxicity.

DACHPt-Loaded Nanoparticles Self-assembled from Biodegradable Dendritic Copolymer Polyglutamic Acid-b-D-α-Tocopheryl Polyethylene Glycol 1000 Succinate for Multidrug Resistant Lung Cancer Therapy

The clinical applications of platinum-based antitumor agents are still largely limited by severe side effects as well as multidrug resistance (MDR). To solve these problems, we developed an 1,2-diaminocyclohexane-platinum(II) (DACHPt)-loaded nanoparticle (NP-TPGS-Pt) by self-assembly of poly(amidoamine)-polyglutamic acid-b-D-α-tocopheryl polyethylene glycol 1000 succinate (PAM-PGlu-b-TPGS) and DACHPt. NP-TPGS-Pt showed robust stability and pH-responsive DACHPt release profile in vitro similar to the PEG-containing nanoparticle (NP-PEG-Pt). Meanwhile, in contrast with NP-PEG-Pt, NP-TPGS-Pt exhibited efficient nanoparticle-based cellular uptake by the Pt-resistant A549/DDP human lung cancer cells and caused much more cytotoxicity than free Oxaliplatin and NP-PEG-Pt. Finally, this NP-TPGS-Pt was proved to perform outstanding inhibition of Pt-resistant tumor growth, much superior than free Oxaliplatin and NP-PEG-Pt. Thus, this NP-TPGS-Pt provides a novel powerful nanomedicine platform for combatting multidrug resistant cancer.

QiShenYiQi Pills, a Compound Chinese Medicine, Prevented Cisplatin Induced Acute Kidney Injury via Regulating Mitochondrial Function

Nephrotoxicity is a serious adverse effect of cisplatin chemotherapy that limits its clinical application, to deal with which no effective management is available so far. The present study was to investigate the potential protective effect of QiShenYiQi Pills (QSYQ), a compound Chinese medicine, against cisplatin induced nephrotoxicity in mice. Pretreatment with QSYQ significantly attenuated the cisplatin induced increase in plasma urea and creatinine, along with the histological damage, such as tubular necrosis, protein cast, and desquamation of epithelial cells, improved the renal microcirculation disturbance as indicated by renal blood flow, microvascular flow velocity, and the number of adherent leukocytes. Additionally, QSYQ prevented mitochondrial dysfunction by preventing the cisplatin induced downregulation of mitochondrial complex activity and the expression of NDUFA10, ATP5D, and Sirt3. Meanwhile, the cisplatin-increased renal thiobarbituric acid-reactive substances, caspase9, cleaved-caspase9, and cleaved-caspase3 were all diminished by QSYQ pretreatment. In summary, the pretreatment with QSYQ remarkably ameliorated the cisplatin induced nephrotoxicity in mice, possibly via the regulation of mitochondrial function, oxidative stress, and apoptosis.

Current FDA-approved treatments for non-small cell lung cancer and potential biomarkers for its detection

BACKGROUND

Lung cancer is the leading worldwide cancer with almost 1.5 million deaths every year. Some drugs for lung cancer treatment have been available on the market for decades, but novel drugs have emerged promising better outcomes, especially for Non-Small Cell Lung Cancer (NSCLC), which represents 75% of lung cancer cases. However, how much do drugs have evolved for NSCLC treatment? Are they sharing the same mechanism of action?

AIM

In this review we analyzed how the approved drugs by Federal Drug Agency for NSCLC have advanced in the last four decades identifying shared mechanism of action of medicines against NSCLC treatment and some of the potential biomarkers for early detection.

RESULTS

Cisplatin and its derivatives are still the most used therapy in combination with some other more specific drugs. However, increasing the survival rates seems to be a great challenge and research is moving into early detection through biomarkers but also trying to identify molecules such as those derived from the immune system, cell-free DNA, non-coding RNAs, but also polymorphisms to detect early tumor formation.

CONCLUSIONS

Cisplatin and derivatives have been one of the most successful therapies in spite of their side effects and low specificity. Some of the drugs developed after cisplatin discovery, have been targeted the epidermal growth factor receptor, anaplastic lymphoma kinase, programmed cell death 1 ligand and vascular endothelial growth factor. Since none of the pharmacological treatments in combination with radiation/surgery have extended dramatically the survival rate, research is now focused in early cancer detection in combination with precision medicine, which attempts to treat patients individually according to their stage and tumor characteristics.

miR-200c Regulation of Metastases in Ovarian Cancer: Potential Role in Epithelial and Mesenchymal Transition

Among the gynecological malignancies, ovarian cancer is the most fatal due to its high mortality rate. Most of the identified cases are epithelial ovarian cancer (EOC) with five distinct subtypes: high-grade serous carcinoma, low-grade serous carcinoma, mucinous carcinoma, endometrioid carcinoma, and clear-cell carcinoma. Lack of an early diagnostic approach, high incidence of tumor relapse and the heterogenous characteristics between each EOC subtypes contribute to the difficulties in developing precise intervention and therapy for the patients. MicroRNAs (miRNAs) are single-stranded RNAs that have been shown to function as tumor suppressors or oncomiRs. The miR-200 family, especially miR-200c, has been shown to be implicated in the metastasis and invasion of ovarian carcinoma due to its functional regulation of epithelial-to-mesenchymal transition (EMT). This mini review is aimed to summarize the recent findings of the miR-200c functional role as well as its validated targets in the metastasis cascade of ovarian cancer, with a focus on EMT regulation. The potential of this miRNA in early diagnosis and its dual expression status are also discussed.

Structure and function of multidrug and toxin extrusion proteins (MATEs) and their relevance to drug therapy and personalized medicine

Multidrug and toxin extrusion (MATE; SLC47A) proteins are membrane transporters mediating the excretion of organic cations and zwitterions into bile and urine and thereby contributing to the hepatic and renal elimination of many xenobiotics. Transported substrates include creatinine as endogenous substrate, the vitamin thiamine and a number of drug agents with in part chemically different structures such as the antidiabetic metformin, the antiviral agents acyclovir and ganciclovir as well as the antibiotics cephalexin and cephradine. This review summarizes current knowledge on the structural and molecular features of human MATE transporters including data on expression and localization in different tissues, important aspects on regulation and their functional role in drug transport. The role of genetic variation of MATE proteins for drug pharmacokinetics and drug response will be discussed with consequences for personalized medicine.

Metal-based drugs that break the rules

Cisplatin and other platinum compounds have had a huge impact in the treatment of cancers and are applied in the majority of anticancer chemotherapeutic regimens. The success of these compounds has biased the approaches used to discover new metal-based anticancer drugs. In this perspective we highlight compounds that are apparently incompatible with the more classical (platinum-derived) concepts employed in the development of metal-based anticancer drugs, with respect to both compound design and the approaches used to validate their utility. Possible design approaches for the future are also suggested.

Targeting copper in cancer therapy: 'Copper That Cancer'

Copper is an essential micronutrient involved in fundamental life processes that are conserved throughout all forms of life. The ability of copper to catalyze oxidation-reduction (redox) reactions, which can inadvertently lead to the production of reactive oxygen species (ROS), necessitates the tight homeostatic regulation of copper within the body. Many cancer types exhibit increased intratumoral copper and/or altered systemic copper distribution. The realization that copper serves as a limiting factor for multiple aspects of tumor progression, including growth, angiogenesis and metastasis, has prompted the development of copper-specific chelators as therapies to inhibit these processes. Another therapeutic approach utilizes specific ionophores that deliver copper to cells to increase intracellular copper levels. The therapeutic window between normal and cancerous cells when intracellular copper is forcibly increased, is the premise for the development of copper-ionophores endowed with anticancer properties. Also under investigation is the use of copper to replace platinum in coordination complexes currently used as mainstream chemotherapies. In comparison to platinum-based drugs, these promising copper coordination complexes may be more potent anticancer agents, with reduced toxicity toward normal cells and they may potentially circumvent the chemoresistance associated with recurrent platinum treatment. In addition, cancerous cells can adapt their copper homeostatic mechanisms to acquire resistance to conventional platinum-based drugs and certain copper coordination complexes can re-sensitize cancer cells to these drugs. This review will outline the biological importance of copper and copper homeostasis in mammalian cells, followed by a discussion of our current understanding of copper dysregulation in cancer, and the recent therapeutic advances using copper coordination complexes as anticancer agents.