Nongenomic Effects of Cisplatin: Acute Inhibition of Mechanosensitive Transporters and Channels without Actin Remodeling

Design, synthesis and mechanistic studies of novel arylformylhydrazone butylphenyltin complexes as potential anticancer agents

Many diorganotin complexes with various alkyl groups exhibit excellent in vitro anticancer activity. However, most diorganotin is the same alkyl group, and the asymmetric alkyl R group has been rarely reported. Hence, in this paper, twenty butylphenyl mixed dialkyltin arylformylhydrazone complexes have been synthesized by microwave "one-pot" reaction with arylformylhydrazine, substituted α-keto acid or its sodium salt and butylphenyltin dichloride. The crystal structures of nine complexes were determined, indicating that the complexes C1, C2, C11, C12, and C16 ∼ C19 possessed a central symmetric structure of a dinuclear Sn2O2 tetrahedral ring; while the complex C9 is a trinuclear tin-oxygen cluster with a 6-membered ring encased in a 12-membered macrocyclic structure. The inhibiting activity of complexes was tested against the human cell lines NCI-H460, MCF-7, HepG2, Huh-7 and HL-7702. Complex C2 demonstrated the optimal inhibitory effect on HepG2 cells, with an IC50 value of 0.82 ± 0.03 μM. Cellular biology experiments revealed that complex C2 could induce apoptosis and G2/M phase cell cycle arrest in HepG2 and Huh-7 cells. The complex also caused the collapse of the mitochondrial membrane potential and increased intracellular reactive oxygen species in HepG2 and Huh-7 cells. Western blot analysis further clarified that complex C2 could induce cell apoptosis through the mitochondrial pathway along with the release of reactive oxygen species.

Inhibition of NHE1 transport activity and gene transcription in DRG neurons in oxaliplatin-induced painful peripheral neurotoxicity

Oxaliplatin (OHP)-induced peripheral neurotoxicity (OIPN), one of the major dose-limiting side effects of colorectal cancer treatment, is characterized by both acute and chronic syndromes. Acute exposure to low dose OHP on dorsal root ganglion (DRG) neurons is able to induce an increase in intracellular calcium and proton concentration, thus influencing ion channels activity and neuronal excitability. The Na⁺/H⁺ exchanger isoform-1 (NHE1) is a plasma membrane protein that plays a pivotal role in intracellular pH (pH_i) homeostasis in many cell types, including nociceptors. Here we show that OHP has early effects on NHE1 activity in cultured mouse DRG neurons: the mean rate of pH_i recovery was strongly reduced compared to vehicle-treated controls, reaching levels similar to those obtained in the presence of cariporide (Car), a specific NHE1 antagonist. The effect of OHP on NHE1 activity was sensitive to FK506, a specific calcineurin (CaN) inhibitor. Lastly, molecular analyses revealed transcriptional downregulation of NHE1 both in vitro, in mouse primary DRG neurons, and in vivo, in an OIPN rat model. Altogether, these data suggest that OHP-induced intracellular acidification of DRG neurons largely depends on CaN-mediated NHE1 inhibition, revealing new mechanisms that OHP could exert to alter neuronal excitability, and providing novel druggable targets.

Equilibrium Studies on Pd(II)-Amine Complexes with Bio-Relevant Ligands in Reference to Their Antitumor Activity

This review article presents an overview of the equilibrium studies on Pd-amine complexes with bio-relevant ligands in reference to their antitumor activity. Pd(II) complexes with amines of different functional groups, were synthesized and characterized in many studies. The complex formation equilibria of Pd(amine)²⁺ complexes with amino acids, peptides, dicarboxylic acids and DNA constituents, were extensively investigated. Such systems may be considered as one of the models for the possible reactions occurring with antitumor drugs in biological systems. The stability of the formed complexes depends on the structural parameters of the amines and the bio-relevant ligands. The evaluated speciation curves can help to provide a pictorial presentation of the reactions in solutions of different pH values. The stability data of complexes with sulfur donor ligands compared with those of DNA constituents, can reveal information regarding the deactivation caused by sulfur donors. The formation equilibria of binuclear complexes of Pd(II) with DNA constituents was investigated to support the biological significance of this class of complexes. Most of the Pd(amine)²⁺ complexes investigated were studied in a low dielectric constant medium, resembling that of a biological medium. Investigations of the thermodynamic parameters reveal that the formation of the Pd(amine)²⁺ complex species is exothermic.

Nucleic Acid Aptamers Increase the Anticancer Efficiency and Reduce the Toxicity of Cisplatin-Arabinogalactan Conjugates In Vivo

Cisplatin is an effective drug for treating various cancer types. However, it is highly toxic for both healthy and tumor cells. Therefore, there is a need to reduce its therapeutic dose and increase targeted bioavailability. One of the ways to achieve this could be the coating of cisplatin with polysaccharides and specific carriers for targeted delivery. Nucleic acid aptamers could be used as carriers for the specific delivery of medicine to cancer cells. Cisplatin-arabinogalactan-aptamer (Cis-AG-Ap) conjugate was synthesized based on Cis-dichlorodiammineplatinum, Siberian larch arabinogalactan, and aptamer AS-42 specific to heat-shock proteins (HSP) 71 kDa (Hspa8) and HSP 90-beta (Hsp90ab1). The antitumor effect was estimated using ascites and metastatic Ehrlich tumor models. Cis-AG-Ap toxicity was assessed by blood biochemistry on healthy mice. Here, we demonstrated enhanced anticancer activity of Cis-AG-Ap and its specific accumulation in tumor foci. It was shown that targeted delivery allowed a 15-fold reduction in the therapeutic dose of cisplatin and its toxicity. Cis-AG-Ap sufficiently suppressed the growth of Ehrlich's ascites carcinoma, the mass and extent of tumor metastasis in vivo. Arabinogalactan and the aptamers promoted cisplatin efficiency by enhancing its bioavailability. The described strategy could be very promising for targeted anticancer therapy.

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.

Insights Into Acute and Delayed Cisplatin-Induced Emesis From a Microelectrode Array, Radiotelemetry and Whole-Body Plethysmography Study of Suncus murinus (House Musk Shrew)

Purpose: Cancer patients receiving cisplatin therapy often experience side-effects such as nausea and emesis, but current anti-emetic regimens are suboptimal. Thus, to enable the development of efficacious anti-emetic treatments, the mechanisms of cisplatin-induced emesis must be determined. We therefore investigated these mechanisms in Suncus murinus, an insectivore that is capable of vomiting.

Methods: We used a microelectrode array system to examine the effect of cisplatin on the spatiotemporal properties of slow waves in stomach antrum, duodenum, ileum and colon tissues isolated from S. murinus. In addition, we used a multi-wire radiotelemetry system to record conscious animals’ gastric myoelectric activity, core body temperature, blood pressure (BP) and heart rate viability over 96-h periods. Furthermore, we used whole-body plethysmography to simultaneously monitor animals’ respiratory activity. At the end of in vivo experiments, the stomach antrum was collected and immunohistochemistry was performed to identify c-Kit and cluster of differentiation 45 (CD45)-positive cells.

Results: Our acute in vitro studies revealed that cisplatin (1–10 μM) treatment had acute region-dependent effects on pacemaking activity along the gastrointestinal tract, such that the stomach and colon responded oppositely to the duodenum and ileum. S. murinus treated with cisplatin for 90 min had a significantly lower dominant frequency (DF) in the ileum and a longer waveform period in the ileum and colon. Our 96-h recordings showed that cisplatin inhibited food and water intake and caused weight loss during the early and delayed phases. Moreover, cisplatin decreased the DF, increased the percentage power of bradygastria, and evoked a hypothermic response during the acute and delayed phases. Reductions in BP and respiratory rate were also observed. Finally, we demonstrated that treatment with cisplatin caused inflammation in the antrum of the stomach and reduced the density of the interstitial cells of Cajal (ICC).

Conclusion: These studies indicate that cisplatin treatment of S. murinus disrupted ICC networking and viability and also affected general homeostatic mechanisms of the cardiovascular system and gastrointestinal tract. The effect on the gastrointestinal tract appeared to be region-specific. Further investigations are required to comprehensively understand these mechanistic effects of cisplatin and their relationship to emesis.

Fabrication, optimisation and evaluation of cisplatin-loaded nanostructured carriers for improved urothelium permeability for intravesical administration

AIM

To design microemulsions as carriers to improve cisplatin permeation capability for intravesical administration.

METHOD

The response surface methodology with factorial design was used to investigate and optimise the influence of the compositions e.g. capryol 90 and 5-pentanediol/transcutol mixture on the permeation accumulation amount and tissue deposition amount of cisplatin-loaded microemulsions. The in vitro permeation study and in vivo intravesical test were conducted to prove the effect of microemulsions.

RESULTS

The droplet size and the viscosity of all drug-loaded formulations ranged 235.8-309.3 nm and 550.8-861.7 cps, respectively. The permeation accumulation amounts significantly increased about 26-fold, by used microemulsion as carriers. In vivo study, the cisplatin deposition amount in bladder tissue significantly increased 4.1-fold (p < 0.05) and the penetration depth increased from 60 μm up 120 μm. The nanocarrier showed considerable thermodynamic stability.

CONCLUSION

The designed nanocarrier was considered to be a promising delivery system for cisplatin intravesical administration.

Platinum complexes inhibit HER-2 enriched and triple-negative breast cancer cells metabolism to suppress growth, stemness and migration by targeting PKM/LDHA and CCND1/BCL2/ATG3 signaling pathways

Triple-negative-breast cancer (TNBC) and HER-2 enriched positive aggressive types of breast cancer and are highly metastatic in nature. Anticancer agents those target TNBC and HER-2 enriched positive breast cancers are considered important in the field of breast cancer research. In search of the effective anticancer agents, we synthesized Pt(II) complexes to target these cancers. Platinum complexes (C1-C8) were prepared in single step by the reaction of commercially available K₂PtCl₄ with the readily prepared ligands (L1-L8). All these compounds were characterized successfully by different spectroscopic and spectrophotometric analyses. Structures of C1, C3 and C8 were characterized by single crystal X-ray analysis that confirmed the exact chelation mode of the SNO-triply coordinated ligand. All these complexes inhibited the in vitro growth of MCF-7 (luminal-like), MDA-MB-231 (TNBC) and SKBR3 (HER-2 enriched) breast cancer cells. C1, C3 and C7 induced cell death and suppressed the clonogenic potential of these cancer cells. Importantly, C1, C3 and C7 showed potentials to suppress cancer stem cells/mammosphere formation and cell migration ability of MDA-MB-231 and SKBR3 breast cancer cells. These complexes also induced cellular senescence in MDA-MB-231 and SKBR3 cells, thus suggesting a cell retardation mechanism. Similarly, these complexes induced DNA damage by activating p-H2AX expression and promoted autophagy via ATG3/LC3B axis activation in MDA-MB-231 and SKBR3 cells. Furthermore, these complexes decreased the expression of oncogenic proteins such as BCL2 and cylin-D1 those are involved in cancer cell survival and cell cycle progression. To further gain insight, we found that C1 and C7 targeted glycolytic pathways by regulating PKM and LDHA expression, which are involved in glycolysis. Moreover, C1 and C7 suppressed the formation of ATP production that is required for cancer cell growth. Taken together, the easy synthesis and biological assays results point towards the importance of these complexes in MDA-MB-231 (TNBC) and SKBR3 (HER-2 enriched) breast cancer cells by targeting multiple signaling pathways those are considered important during breast cancer progression. This study produces bases for further deeper in vitro or in vivo study that could lead to the effective breast cancer agents which we are working on.

Determining factors of renal dysfunction during cisplatin chemotherapy

Cisplatin remains one of the most active antineoplastic treatments used in oncology, being the most prestigious exponent of the golden age in chemotherapy at the end of the 20th century. This chemotherapeutic drug is used for curative or palliative treatments in testicular, ovarian, head and neck neoplasms, sarcomas and lymphomas. The limiting dose adverse effect of cisplatin is nephrotoxicity. The present study aimed to evaluate the magnitude of the damage to renal function and to identify the risk or protective factors in renal toxicity. The retrospective study was performed using 81 consecutive patients who underwent at least three cycles of cisplatin chemotherapy. The results indicate an average decline in glomerular filtration rate (GFR) of 9 ml/min. Women appear to be less by a decline in renal function (a relative decline of GFR of -5% for women compared to -9% for men). The decline in GFR was found to be proportional to age; overweight (not obese) individuals had the best renal function behavior under cisplatin treatment, while the association of anaemia appears to be a risk factor for renal toxicity. The use of cisplatin in oncology in the last years may have decreased, either by using combination chemotherapy instead of monotherapy, or by its displacement by newly discovered treatments (e.g., immunotherapy in lung cancer). Therefore, it is possible that the profile of patients who are exposed to this drug and the duration of exposure have been modified compared to previous studies. The objectives of the present study were to assess the magnitude of the renal function damage during cisplatin treatment and to identify the risk and the protective factors in term of renal toxicity.

Early Stimulation of TREK Channel Transcription and Activity Induced by Oxaliplatin-Dependent Cytosolic Acidification

Oxaliplatin-induced peripheral neuropathy is characterized by an acute hyperexcitability syndrome triggered/exacerbated by cold. The mechanisms underlying oxaliplatin-induced peripheral neuropathy are unclear, but the alteration of ion channel expression and activity plays a well-recognized central role. Recently, we found that oxaliplatin leads to cytosolic acidification in dorsal root ganglion (DRG) neurons. Here, we investigated the early impact of oxaliplatin on the proton-sensitive TREK potassium channels. Following a 6-h oxaliplatin treatment, both channels underwent a transcription upregulation that returned to control levels after 42 h. The overexpression of TREK channels was also observed after in vivo treatment in DRG cells from mice exposed to acute treatment with oxaliplatin. Moreover, both intracellular pH and TREK channel transcription were similarly regulated after incubation with amiloride, an inhibitor of the Na⁺/H⁺ exchanger. In addition, we studied the role of oxaliplatin-induced acidification on channel behavior, and, as expected, we observed a robust positive modulation of TREK channel activity. Finally, we focused on the impact of this complex modulation on capsaicin-evoked neuronal activity finding a transient decrease in the average firing rate following 6 h of oxaliplatin treatment. In conclusion, the early activation of TREK genes may represent a mechanism of protection against the oxaliplatin-related perturbation of neuronal excitability.

Efficient enzyme-activated therapy based on the different locations of protein and prodrug in nanoMOFs

Enzyme-activated prodrug therapy (EAPT) is an effective cancer treatment strategy able to transport non-toxic prodrugs and subsequently convert them into drugs at specific times and locations. However, due to the limitation of easy biodegradability and the membrane-impermeable characteristic of exogenous enzymes, there is a need to exploit suitable carriers for the effective protection and simultaneous delivery of activating enzymes into cancer cells. Herein, hierarchically porous MOFs were employed for the loading of enzyme and prodrug in a single nanocarrier thanks to their different cavity sizes. The simple loading process allows entrapping of horseradish peroxidase (HRP) and a monocarboxyl-containing indole-3-acetic acid (IAA) prodrug with high loading capacities in different spaces, which keeps the catalytic activity of the enzyme perfectly intact and avoids the premature activation of the prodrug. The encapsulated HRP and IAA exhibit sustained and synchronized release behaviors. Compared to the native HRP enzyme, the current MOF nanocarriers not only facilitate enzyme delivery into cellular lysosomes and subsequent endosomal escape, but also effectively release enzyme and prodrug in the intracellular environment within 48 h. Eventually, HRP and IAA loaded MOF nanocarriers cause significant cell death with a low IC₅₀ of 4.2 mg L^-1, while the IAA prodrug alone is non-toxic even at high concentrations. Thus, hierarchically porous MOFs might offer a promising platform for EAPT with a highly consistent spatiotemporal distribution of enzymes and prodrugs in target tissues.

Unexpected therapeutic effects of cisplatin

Cisplatin is a widely used chemotherapeutic agent that is clinically approved to fight both carcinomas and sarcomas. It has relatively high efficiency in treating ovarian cancers and metastatic testicular cancers. It is generally accepted that the major mechanism of cisplatin anti-cancer action is DNA damage. However, cisplatin is also effective in metastatic cancers and should, therefore, affect slow-cycling cancer stem cells in some way. In this review, we focused on the alternative effects of cisplatin that can support a good therapeutic response. First, attention was paid to the effects of cisplatin at the cellular level such as changes in intracellular pH and cellular mechanical properties. Alternative cellular targets of cisplatin, and the effects of cisplatin on cancer cell metabolism and ER stress were also discussed. Furthermore, the impacts of cisplatin on the tumor microenvironment and in the whole organism context were reviewed. In this review, we try to reveal possible causes of the unexpected effectiveness of this anti-cancer drug.

Intracellular Ca2+ Cascade Guided by NIR-II Photothermal Switch for Specific Tumor Therapy

Currently, patients receiving cancer treatments routinely suffer from distressing toxic effects, most originating from premature drug leakage, poor biocompatibility, and off-targeting. For tackling this challenge, we construct an intracellular Ca2+ cascade for tumor therapy via photothermal activation of TRPV1 channels. The nanoplatform creates an artificial calcium overloading stress in specific tumor cells, which is responsible for efficient cell death. Notably, this efficient treatment is activated by mild acidity and TRPV1 channels simultaneously, which contributes to precise tumor therapy and is not limited to hypoxic tumor. In addition, Ca2+ possesses inherent unique biological effect and normal cells are more tolerant of the undesirable destructive influence than tumor cells. The Ca2+ overload leads to cell death due to mitochondrial dysfunction (upregulation of Caspase-3, cytochrome c, and downregulation of Bcl-2 and ATP), and in vivo, the released photothermal CuS nanoparticles allow an enhanced 3D photoacoustic imaging and provide instant diagnosis.

Antitumour and Toxicity Evaluation of a Ru(II)-Cyclopentadienyl Complex in a Prostate Cancer Model by Imaging Tools

BACKGROUND

Ruthenium complexes have been extensively investigated for their prospective value as alternatives to cisplatin. Recently, we reported the in vitro anticancer properties of a family of organometallic ruthenium( II)-cyclopentadienyl complexes and have explored their mechanism of action.

OBJECTIVE

The purpose of this study was to evaluate the in vivo antitumour efficacy and toxicity of one of these Ru(II) compounds, [RuCp(mTPPMSNa)(2,2'-bipy)][CF3SO2] (TM85) which displayed an interesting spectrum of activity against several cancer cells.

METHODS

Studies to assess the antitumour activity and toxicity were performed in a metastatic prostate (PC3) mice model using ICP-MS, nuclear microscopy, elemental analysis and Transmission Electron Microscopy (TEM).

RESULTS

TM85 showed low systemic toxicity but no significant tumour reduction, when administered at tolerated dose (20mg/kg) over 10 days. Ru was mainly retained in the liver and less in kidneys, with low accumulation in tumour. Increased bilirubin levels, anomalous Ca and Fe concentrations in liver and mitochondria alterations were indicative of liver injury. The hepatotoxicity observed was less severe than that of cisplatin and no nephrotoxicity was found.

CONCLUSION

Under the experimental conditions of this study, TM85 is less toxic than cisplatin, induces similar tumour reduction and avoids the formation of metastatic foci. No renal toxicity was observed by the analysis of creatinine levels and the effective renal plasma flow by 99mTc-MAG3 clearance. Hence, it can be considered a valuable compound for further studies in the field of Ru-based anticancer drugs.

Diversity of complexes based on p-nitrobenzoylhydrazide, benzoylformic acid and diorganotin halides or oxides self-assemble: Cytotoxicity, the induction of apoptosis in cancer cells and DNA-binding properties

Eight organotin(IV) complexes (C1-C8) have been synthesized and characterized by elemental analysis, fourier transform infrared spectroscopy (FT-IR), multinuclear nuclear magnetic resonance (¹H, ¹³C and ¹¹⁹Sn NMR), high resolution mass spectroscopy (HRMS) and single crystal X-ray structural analysis. Crystallographic data show that C1 was a tetranuclear 16-membered macrocycle complex, C2-C4 and C7 were centrosymmetric dimer distannoxane and there was a Sn₂O₂ four-membered ring in the middle of the molecule, respectively, C5 and C6 are monoorganotin complexes due to the dehydroalkylation effect during the reaction, while C8 forms a one-dimensional chain structure. The cytotoxicity of all complexes were tested by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assays against three human tumor cell lines NCI-H460, MCF-7 and HepG2. The dibutyltin complex C2 has been shown to be more potent antitumor agents than other complexes and carboplatin. Cell apoptosis study of C2 with the high activity on HepG2 and MCF-7 cancer cell lines was investigated by flow cytometry, it was shown that the antitumor activity of C2 was related to apoptosis, but it has different cell cycle arrest characteristics from platinum compounds, and the proliferation was inhibited by blocking cells in S phase. The DNA binding activity of the C2 was studied by UV-visible absorption spectrometry, fluorescence competitive, viscosity measurements and gel electrophoresis, results shown C2 can be well embedded in the double helix of DNA and cleave DNA.

The SLC9A-C Mammalian Na+/H+ Exchanger Family: Molecules, Mechanisms, and Physiology

Na⁺/H⁺ exchangers play pivotal roles in the control of cell and tissue pH by mediating the electroneutral exchange of Na⁺ and H⁺ across cellular membranes. They belong to an ancient family of highly evolutionarily conserved proteins, and they play essential physiological roles in all phyla. In this review, we focus on the mammalian Na⁺/H⁺ exchangers (NHEs), the solute carrier (SLC) 9 family. This family of electroneutral transporters constitutes three branches: SLC9A, -B, and -C. Within these, each isoform exhibits distinct tissue expression profiles, regulation, and physiological roles. Some of these transporters are highly studied, with hundreds of original articles, and some are still only rudimentarily understood. In this review, we present and discuss the pioneering original work as well as the current state-of-the-art research on mammalian NHEs. We aim to provide the reader with a comprehensive view of core knowledge and recent insights into each family member, from gene organization over protein structure and regulation to physiological and pathophysiological roles. Particular attention is given to the integrated physiology of NHEs in the main organ systems. We provide several novel analyses and useful overviews, and we pinpoint main remaining enigmas, which we hope will inspire novel research on these highly versatile proteins.

Analyzing chemotherapy-induced peripheral neuropathy in vivo using non-mammalian animal models

Non-mammalian models of CIPN remain relatively sparse, but the knowledge gained from the few published studies suggest that these species have great potential to serve as a discovery platform for new pathways and underlying genetic mechanisms of CIPN. These models permit large-scale genetic and pharmacological screening, and they are highly suitable for in vivo imaging. CIPN phenotypes described in rodents have been confirmed in those models, and conversely, genetic players leading to axon de- and regeneration under conditions of chemotherapy treatment identified in these non-mammalian species have been validated in rodents. Given the need for non-traditional approaches with which to identify new CIPN mechanisms, these models bear a strong potential due to the conservation of basic mechanisms by which chemotherapeutic agents induce neurotoxicity.

Cisplatin-Membrane Interactions and Their Influence on Platinum Complexes Activity and Toxicity

Cisplatin and other platinum(II) analogs are widely used in clinical practice as anti-cancer drugs for a wide range of tumors. The primary mechanism by which they exert their action is through the formation of adducts with genomic DNA. However, multiple cellular targets by platinum(II) complexes have been described. In particular, the early events occurring at the plasma membrane (PM), i.e., platinum-membrane interactions seem to be involved in the uptake, cytotoxicity and cell-resistance to cisplatin. In fact, PM influences signaling events, and cisplatin-induced changes on membrane organization and fluidity were shown to activate apoptotic pathways. This review critically discusses the sequence of events caused by lipid membrane-platinum interactions, with emphasis on the mechanisms that lead to changes in the biophysical properties of the membranes (e.g., fluidity and permeability), and how these correlate with sensitivity and resistance phenotypes of cells to platinum(II) complexes.

Real-Time Visualization of Cell Membrane Damage Using Gadolinium-Schiff Base Complex-Doped Quantum Dots

Despite the importance of cell membranes for maintenance of integrity of cellular structures, there is still a lack of methods that allow simple real-time visualization of their damage. Herein, we describe gadolinium-Schiff base-doped quantum dots (GdQDs)-based probes for a fast facile spatial labeling of membrane injuries. We found that GdQDs preferentially interact through electron-rich and hydrophobic residues with a specific sequence motif of NHE-RF2 scaffold protein, exposed upon membrane damage. Such interaction results in a fast formation of intensively fluorescent droplets with a higher resolution and in a much shorter time compared to immunofluorescence using organic dye. GdQDs have high stability, brightness, and considerable cytocompatibility, which enable their use in long-term experiments in living cultures. To the best of our knowledge, this is the first report, demonstrating a method allowing real-time monitoring of membrane damage and recovery without any special requirements for instrumentation. Because of intensive brightness and simple signal pattern, GdQDs allow easy examination of interactions between cellular membranes and cell-penetrating peptides or cytostatic drugs. We anticipate that the simple and flexible method will also facilitate the studies dealing with host-pathogen interactions.

Oxaliplatin induces pH acidification in dorsal root ganglia neurons

Oxaliplatin induced peripheral neurotoxicity is characterized by an acute cold-induced syndrome characterized by cramps, paresthesias/dysesthesias in the distal limbs and perioral region, that develops rapidly and lasts up to one week affecting nearly all the patients as well as by long-lasting symptoms. It has been previously shown that pharmacological or genetic ablation of TRPA1 responses reduces oxaliplatin-induced peripheral neurotoxicity in mouse models. In the present report, we show that treatment with concentrations of oxaliplatin similar to those found in plasma of treated patients leads to an acidification of the cytosol of mouse dorsal root ganglia neurons in culture and this in turn is responsible for sensitization of TRPA1 channels, thereby providing a mechanistic explanation to toxicity of oxaliplatin. Reversal of the acidification indeed leads to a significantly reduced activity of TRPA1 channels. Last, acidification occurs also in vivo after a single injection of therapeutically-relevant doses of oxaliplatin.

Ferrocene-Containing Impiridone (ONC201) Hybrids: Synthesis, DFT Modelling, In Vitro Evaluation, and Structure⁻Activity Relationships

Inspired by the well-established clinical evidence about the interplay between apoptotic TRAIL (tumour necrosis factor-related apoptosis-inducing ligand) mechanism and reactive oxygen species (ROS)-mediated oxidative stress, a set of novel ONC201 hybrids containing the impiridone core and one or two differently positioned ferrocenylalkyl groups were synthesised in our present work. These two types of residues have been implicated in the aforementioned mechanisms associated with cytotoxic activity. A straightforward, primary amine-based synthetic approach was used allowing the introduction of a variety of N-substituents into the two opposite regions of the heterocyclic skeleton. Reference model compounds with benzyl and halogenated benzyl groups were also synthesised and tested. The in vitro assays of the novel impiridones on five malignant cell lines disclosed characteristic structure-activity relationship (SAR) featuring significant substituent-dependent activity and cell-selectivity. A possible contribution of ROS-mechanism to the cytotoxicity of the novel metallocenes was suggested by density functional theory (DFT)studies on simplified models. Accordingly, unlike the mono-ferrocenylalkyl-substituted products, the compounds containing two ferrocenylalkyl substituents in the opposite regions of the impiridone core display a much more pronounced long-term cytotoxic effect against A-2058 cell line than do the organic impiridones including ONC201 and ONC212. Furthermore, the prepared bis-metallocene derivatives also present substantial activity against COLO-205- and EBC-1 cell lines.

Enzyme-MOF Nanoreactor Activates Nontoxic Paracetamol for Cancer Therapy

Prodrug activation, by exogenously administered enzymes, for cancer therapy is an approach to achieve better selectivity and less systemic toxicity than conventional chemotherapy. However, the short half-lives of the activating enzymes in the bloodstream has limited its success. Demonstrated here is that a tyrosinase-MOF nanoreactor activates the prodrug paracetamol in cancer cells in a long-lasting manner. By generating reactive oxygen species (ROS) and depleting glutathione (GSH), the product of the enzymatic conversion of paracetamol is toxic to drug-resistant cancer cells. Tyrosinase-MOF nanoreactors cause significant cell death in the presence of paracetamol for up to three days after being internalized by cells, while free enzymes totally lose activity in a few hours. Thus, enzyme-MOF nanocomposites are envisioned to be novel persistent platforms for various biomedical applications.

Feeling Stress: The Mechanics of Cancer Progression and Aggression

The tumor microenvironment is a dynamic landscape in which the physical and mechanical properties evolve dramatically throughout cancer progression. These changes are driven by enhanced tumor cell contractility and expansion of the growing tumor mass, as well as through alterations to the material properties of the surrounding extracellular matrix (ECM). Consequently, tumor cells are exposed to a number of different mechanical inputs including cell–cell and cell-ECM tension, compression stress, interstitial fluid pressure and shear stress. Oncogenes engage signaling pathways that are activated in response to mechanical stress, thereby reworking the cell's intrinsic response to exogenous mechanical stimuli, enhancing intracellular tension via elevated actomyosin contraction, and influencing ECM stiffness and tissue morphology. In addition to altering their intracellular tension and remodeling the microenvironment, cells actively respond to these mechanical perturbations phenotypically through modification of gene expression. Herein, we present a description of the physical changes that promote tumor progression and aggression, discuss their interrelationship and highlight emerging therapeutic strategies to alleviate the mechanical stresses driving cancer to malignancy.

A (salicylaldiminato)Pt(II) complex with dimethylpropylene linkage: Synthesis, structural characterization and antineoplastic activity

A novel (salicylaldiminato)Pt(II) complex with two different molecular structures, one solventless ((salicylaldiminato)Pt(II)) 1 and another one solvated ((salicylaldiminato)Pt(II). C₂H₅OH), 1·C₂H₅OH, has been obtained by the reaction of a salen ligand with [PtCl₂(DMSO)₂] in ethanol at room temperature. The asymmetric unit of solventless 1 contains 9 such complex molecules whereas 1·C₂H₅OH contains 2 complex molecules and one ethanol molecule. To get insights into the structure and bonding, DFT and TDFT calculation have been carried out. The electronic transition band at 408.0nm (calc. 424.3nm) is assigned to HOMO→LUMO (96%) excitation. The calculated NMR chemical shifts are interrelated with the experimental results, and a very slight effect of solvent was noticed on NMR chemical shifts. A MTT assay and the real-time cell monitoring xCELLigence system revealed that the 1 has significant potential to suppress cell viability and cell proliferation in human HT-29 and SW620 colorectal cancer cell lines.

Chemotherapy with cisplatin: insights into intracellular pH and metabolic landscape of cancer cells in vitro and in vivo

Although cisplatin plays a central role in cancer chemotherapy, the mechanisms of cell response to this drug have been unexplored. The present study demonstrates the relationships between the intracellular pH (pHi), cell bioenergetics and the response of cervical cancer to cisplatin. pHi was measured using genetically encoded sensor SypHer2 and metabolic state was accessed by fluorescence intensities and lifetimes of endogenous cofactors NAD(P)H and FAD. Our data support the notion that cisplatin induces acidification of the cytoplasm early after the treatment. We revealed in vitro that a capacity of cells to recover and maintain alkaline pHi after the initial acidification is the crucial factor in mediating the cellular decision to survive and proliferate at a vastly reduced rate or to undergo cell death. Additionally, we showed for the first time that pHi acidification occurs after prolonged therapy in vitro and in vivo, and this, likely, favors metabolic reorganization of cells. A metabolic shift from glycolysis towards oxidative metabolism accompanied the cisplatin-induced inhibition of cancer cell growth in vitro and in vivo. Overall, these findings contribute to an understanding of the mechanisms underlying the responsiveness of an individual cell and tumor to therapy and are valuable for developing new therapeutic strategies.

Ginsenoside Rb1 ameliorates cisplatin-induced learning and memory impairments

Background

Ginsenoside Rb1 (Rb1), a dominant component from the extract of Panax ginseng root, exhibits neuroprotective functions in many neurological diseases. This study was intended to investigate whether Rb1 can attenuate cisplatin-induced memory impairments and explore the potential mechanisms.

Methods

Cisplatin was injected intraperitoneally with a dose of 5 mg/kg/wk, and Rb1 was administered in drinking water at the dose of 2 mg/kg/d to rats for 5 consecutive wk. The novel objects recognition task and Morris water maze were used to detect the memory of rats. Nissl staining was used to examine the neuron numbers in the hippocampus. The activities of superoxide dismutase, glutathione peroxidase, cholineacetyltransferase, acetylcholinesterase, and the levels of malondialdehyde, reactive oxygen species, acetylcholine, tumor necrosis factor-α, interleukin-1β, and interleukin-10 were measured by ELISA to assay the oxidative stress, cholinergic function, and neuroinflammation in the hippocampus.

Results

Rb1 administration effectively ameliorates the memory impairments caused by cisplatin in both novel objects recognition task and Morris water maze task. Rb1 also attenuates the neuronal loss induced by cisplatin in the different regions (CA1, CA3, and dentate gyrus) of the hippocampus. Meanwhile, Rb1 is able to rescue the cholinergic neuron function, inhibit the oxidative stress and neuroinflammation in cisplatin-induced rat brain.

Conclusion

Rb1 rescues the cisplatin-induced memory impairment via restoring the neuronal loss by reducing oxidative stress and neuroinflammation and recovering the cholinergic neuron functions.

New imidoyl-indazole platinum (II) complexes as potential anticancer agents: Synthesis, evaluation of cytotoxicity, cell death and experimental-theoretical DNA interaction studies

Four new neutral N,N imidoyl-indazole ligands (L1, L3, L6, L7) and six new Pt(II)-based complexes (C1-5 and C7) were synthesized and characterized by spectroscopic and spectrometric techniques. Additionally, compounds L6, L7, C3, C5 and C7 were analyzed using X-ray diffraction. An evaluation of cytotoxicity and cell death in vitro for both ligands and complexes was performed by colorimetric assay and flow cytometry, in four cancer cell lines and VERO cells as the control, respectively. Cytotoxicity and selectivity demonstrated by each compound were dependent on the cancer cell line assayed. IC₅₀ values of complexes C1-5 and C7 were lower than those exhibited for the reference drug cisplatin, and selectivity of these complexes was in general terms greater than cisplatin on three cancer cell lines studied. In HL60 cells, complexes C1 and C5 exhibited the lowest values of IC₅₀ and were almost five times more selective than cisplatin. Flow cytometry results suggest that each complex predominantly induced necrosis, and its variant necroptosis, instead of apoptosis in all cancer cell lines studied. DNA binding assays, using agarose gel electrophoresis and UV-visible spectrophotometry studies, displayed a strong interaction only between C4 and DNA. In fact, theoretical calculations showed that C4-DNA binding complex was the most thermodynamic favorable interaction among the complexes in study. Overall, induction of cell death by dependent and independent-DNA-metal compound interactions were possible using imidoyl-indazole Pt(II) complexes as anticancer agents.

CD95-Mediated Proton Regulation

The Na⁺/H⁺ exchanger NHE1 is at the crossroads of a large diversity of signaling pathways, whose activation modifies the cooperative response of the transporter to intracellular H⁺ ions. Here we show how the activation of the Na⁺/H⁺ exchanger NHE1 by the cleaved ligand of CD95 can be measured. We demonstrate two different methods designed to set intracellular pH at precise values. Then we show how these can be coupled to fast kinetics of lithium transport, which will enable to measure the NHE1 activity like for an enzyme, because they will yield rates of transport.

Protective effect of selenium against cisplatin-induced nasopharyngeal cancer in male albino rats

The present study evaluated the protective effect of selenium against cisplatin-induced nasopharyngeal cancer in the cardiac tissue of adult rats. Male Wistar rats were divided into 4 groups of 6 rats each. Different combinations of selenium and cisplatin were administered for 45 days, following which the animals were sacrificed and the nasopharyngeal tissue was surgically removed. Lipid peroxidation, reduced glutathione, and the antioxidant enzymes superoxide dismutase (SOD), catalase and lactate dehydrogenase (LDH) were measured. Apoptotic-related gene (p53, bax and caspase 3) mRNA expression was determined using quantitative polymerase chain reaction. Caspase 3 activity was also measured in all the groups. The results demonstrated that selenium significantly reduced the levels of malondialdehyde. The levels of glutathione, SOD, LDH and catalase significantly increased following selenium treatment. Relative mRNA expression (p53, bax and caspase 3) was significantly reduced in the cisplatin-treated rats, but it significantly increased following selenium treatment. The anticancer activity of selenium was also investigated in HK1cells. Fluorescence and confocal microscopy were used to analyze apoptosis and reactive oxygen species. The protective effect of selenium was also evident through caspase 3 activity, which significantly increased following selenium treatment. Taken together, these results indicate that selenium may be beneficial against cisplatin-induced nasopharyngeal cancer.

Sulfonated Schiff base Sn(IV) complexes as potential anticancer agents

Syntheses, crystal structures and biological activities of the diphenoxo-bridged diorgano dinuclear Sn(IV) compounds [Sn(Et)₂(HL)(H₂O)]₂ (1) and [Sn(n-Bu)₂(HL)(H₂O)]₂ (2) derived from the Schiff base 2-[(2,3-dihydroxyphenyl)methylideneamino]benzenesulfonic acid trihydrate (H₃L·3H₂O) are described. The monoprotonated form (HL^2-) of the Schiff base behaves as O,O'-bidentate ligand, chelating the metal by the two phenoxo oxygen atoms. The hexacoordinated metal centres in 1 and 2 are bridged by a phenoxo oxygen and the remaining coordination positions are fulfilled by the other phenoxo oxygen, two organic groups (ethyl for 1 and n-butyl for 2) and a water molecule. A two dimensional zigzag sheet in 1 and three dimensional polymeric networks in H₃L·3H₂O and 2 are stabilized by a number of non-covalent, H-bonding and π⋯π stacking interactions. The DNA binding activities of these complexes have been studied by UV-vis and fluorescence spectroscopies. Their antiproliferative efficacies have been evaluated on A-549, HeLa and MDA-MB-231 cancer cell lines by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. IC₅₀ values (1.35±0.23, 2.43±0.54 and 1.74±0.04μM for 2) are indicative of a substantial cytotoxicity of 2, mainly towards the A-549 lung cancer cell line. The greater antiproliferative efficacy of 2has further been studied by fluorescence activated cell sorting (FACS) and nuclear morphology by Hoechst/propidium iodide (PI) double staining method. The possible mode of the apoptotic pathway for 2has been substantiated by the reactive oxygen species (ROS) generation studies.

Using Single-Cell Amperometry To Reveal How Cisplatin Treatment Modulates the Release of Catecholamine Transmitters during Exocytosis

The pretreatment of cultured pheochromocytoma (PC12) cells with cis-diamminedichloroplatinum (cisplatin), an anti-cancer drug, influences the exocytotic ability of the cells in a dose-dependent manner. Low concentrations of cisplatin stimulate catecholamine release whereas high concentrations inhibit it. Single-cell amperometry reflects that 2 μm cisplatin treatment increases the frequency of exocytotic events and reduces their duration, whereas 100 μm cisplatin treatment decreases the frequency of exocytotic events and increases their duration. Furthermore, the stability of the initial fusion pore that is formed in the lipid membrane during exocytosis is also regulated differentially by different cisplatin concentrations. This study thus suggests that cisplatin influences exocytosis by multiple mechanisms.

Revisiting CFTR inhibition: a comparative study of CFTRinh -172 and GlyH-101 inhibitors

BACKGROUND AND PURPOSE

For decades, inhibitors of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel have been used as tools to investigate the role and function of CFTR conductance in cystic fibrosis research. In the early 2000s, two new and potent inhibitors of CFTR, CFTR_inh-172 and GlyH-101, were described and are now widely used to inhibit specifically CFTR. However, despite some evidence, the effects of both drugs on other types of Cl⁻-conductance have been overlooked. In this context, we explore the specificity and the cellular toxicity of both inhibitors in CFTR-expressing and non–CFTR-expressing cells.

EXPERIMENTAL APPROACH

Using patch-clamp technique, we tested the effects of CFTR_inh-172 and GlyH-101 inhibitors on three distinct types of Cl⁻ currents: the CFTR-like conductance, the volume-sensitive outwardly rectifying Cl⁻ conductance (VSORC) and finally the Ca²⁺-dependent Cl⁻ conductance (CaCC). We also explored the effect of both inhibitors on cell viability using live/dead and cell proliferation assays in two different cell lines.

KEY RESULTS

We confirmed that these two compounds were potent inhibitors of the CFTR-mediated Cl⁻ conductance. However,GlyH-101 also inhibited the VSORC conductance and the CaCC at concentrations used to inhibit CFTR. The CFTR_inh-172 did not affect the CaCC but did inhibit the VSORC, at concentrations higher than 5 µM. Neither inhibitor (20 µM; 24 h exposure) affected cell viability, but both were cytotoxic at higher concentrations.

CONCLUSIONS AND IMPLICATIONS

Both inhibitors affected Cl⁻ conductances apart from CFTR. Our results provided insights into their use in mouse models.

Sensing cisplatin-induced permeation of single live human bladder cancer cells by scanning electrochemical microscopy

Cisplatin is a widely used anti-cancer agent, which was believed to trigger apoptosis of cancer cells by forming DNA adducts. However, recent studies evidenced a cisplatin-induced extrinsic apoptotic pathway through interaction with plasma membranes. We present quantitative time-course imaging of cisplatin-induced permeation of ferrocenemethanol to single live human bladder cancer cells (T24) using scanning electrochemical microscopy (SECM). Simultaneous quantification of cellular topography and membrane permeability was realized by running SECM in the depth scan mode. It was demonstrated that the acute addition of cisplatin to the outer environment of T24 cells immediately induced membrane permeability change in 5 min, which indicated a loosened structure of the cellular membrane upon cisplatin dosage. The cisplatin-induced permeation of T24 cells might be a one-step action, an extrinsic mechanism, since the cell response was quick, and no continuous increase in the membrane permeability was observed. The time-lapse SECM depth scan method provided a simple and facile way of monitoring cisplatin-induced membrane permeability changes. Our study is anticipated to lead to a methodology of screening anti-cancer drugs through their interactions with live cells.

EDTA capped iron oxide nanoparticles magnetic micelles: drug delivery vehicle for treatment of chronic myeloid leukemia and T1–T2 dual contrast agent for magnetic resonance imaging

This study shows that multiple functionalities like drug delivery and T₁–T₂ dual modalities can be achieved by a proper surface architecture.

Optimized combinations of bortezomib, camptothecin, and doxorubicin show increased efficacy and reduced toxicity in treating oral cancer

Oral cancer continues to be a major cause of morbidity and mortality worldwide. Treatment of oral cancer with combinatorial drugs is increasingly being performed as drugs with different molecular targets often exert synergistic effects, thereby enhancing treatment efficacy. Current combinatorial drug regimens often combine the tolerable dosages of individual drugs. However, the optimized ratio of a drug combination and sequence of drug administration could contribute toward the synergy, leading to increased efficacy and reduced dosages. This report aims to study the possible synergistic effects of three anticancer drugs, a proteasome inhibitor, bortezomib, a topoisomerase I inhibitor, Camptothecin, and a DNA intercalation drug, Doxorubicin, when used in combination for treating oral cancer. To rapidly optimize the three-drug regimen with minimal experimental efforts, a Feedback System Control optimization technique, a recent platform technique developed particularly for drug combination screening, was applied. The optimized regimen showed a therapeutic window (death rate difference between cancer cells and normal cells) close to 100%. This is the first report on the use of a combination of bortezomib, Camptothecin, and Doxorubicin in the treatment of oral cancer. Our results indicate that to have the most synergistic anticancer effect, the drugs in the optimized regimen should be dosage specific and ratio specific. Furthermore, the sequence of drug administration plays a vital role in ensuring that the combination is effective. The optimized regimen reported here has the potential to considerably increase the cure rate of oral cancer and reduce the toxicity of chemotherapy.