Modulation of mitomycin C-induced multidrug resistance in vitro

Local anaesthetics and chemotherapeutic agents: a systematic review of preclinical evidence of interactions and cancer biology

Background

Local anaesthetics are widely used for their analgesic and anaesthetic properties in the perioperative setting, including surgical procedures to excise malignant tumours. Simultaneously, chemotherapeutic agents remain a cornerstone of cancer treatment, targeting rapidly dividing cancer cells to inhibit tumour growth. The potential interactions between these two drug classes have drawn increasing attention and there are oncological surgical contexts where their combined use could be considered. This review examines existing evidence regarding the interactions between local anaesthetics and chemotherapeutic agents, including biological mechanisms and clinical implications.

Methods

A systematic search of electronic databases was performed as per Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. Selection criteria were designed to capture in vitro, in vivo, and clinical studies assessing interactions between local anaesthetics and a wide variety of chemotherapeutic agents. Screening and data extraction were performed independently by two reviewers. The data were synthesised using a narrative approach because of the anticipated heterogeneity of included studies.

Results

Initial searches yielded 1225 relevant articles for screening, of which 43 met the inclusion criteria. The interactions between local anaesthetics and chemotherapeutic agents were diverse and multifaceted. In vitro studies frequently demonstrated altered cytotoxicity profiles when these agents were combined, with variations depending on the specific drug combination and cancer cell type. Mechanistically, some interactions were attributed to modifications in efflux pump activity, tumour suppressor gene expression, or alterations in cellular signalling pathways associated with tumour promotion. A large majority of in vitro studies report potentially beneficial effects of local anaesthetics in terms of enhancing the antineoplastic activity of chemotherapeutic agents. In animal models, the combined administration of local anaesthetics and chemotherapeutic agents showed largely beneficial effects on tumour growth, metastasis, and overall survival. Notably, no clinical study examining the possible interactions of local anaesthetics and chemotherapy on cancer outcomes has been reported.

Conclusions

Reported preclinical interactions between local anaesthetics and chemotherapeutic agents are complex and encompass a spectrum of effects which are largely, although not uniformly, additive or synergistic. The clinical implications of these interactions remain unclear because of the lack of prospective trials. Nonetheless, the modulation of chemotherapy effects by local anaesthetics warrants further clinical investigation in the context of cancer surgery where they could be used together.

Clinical trial registration

Open Science Framework (OSF, project link: https://osf.io/r2u4z).

Synthesis, Structure and In Vitro Cytotoxic Activity of Novel Cinchona-Chalcone Hybrids with 1,4-Disubstituted- and 1,5-Disubstituted 1,2,3-Triazole Linkers

By means of copper(I)-and ruthenium(II)-catalyzed click reactions of quinine- and quinidine-derived alkynes with azide-substituted chalcones a systematic series of novel cinchona-chalcone hybrid compounds, containing 1,4-disubstituted- and 1,5-disubstituted 1,2,3-triazole linkers, were synthesized and evaluated for their cytotoxic activity on four human malignant cell lines (PANC-1, COLO-205, A2058 and EBC-1). In most cases, the cyclization reactions were accompanied by the transition-metal-catalyzed epimerization of the C9-stereogenic centre in the cinchona fragment. The results of the in vitro assays disclosed that all the prepared hybrids exhibit marked cytotoxicity in concentrations of low micromolar range, while the C9-epimerized model comprising quinidine- and (E)-1-(4-(3-oxo-3-(3,4,5-trimethoxyphenyl)prop-1-en-1-yl)phenyl) fragments, connected by 1,5-disubstituted 1,2,3-triazole linker, and can be regarded as the most potent lead of which activity is probably associated with a limited conformational space allowing for the adoption of a relatively rigid well-defined conformation identified by DFT modelling. The mechanism of action of this hybrid along with that of a model with markedly decreased activity were approached by comparative cell-cycle analyses in PANC-1 cells. These studies disclosed that the hybrid of enhanced antiproliferative activity exerts significantly more extensive inhibitory effects in subG1, S and G2/M phases than does the less cytotoxic counterpart.

Multidrug resistance (MDR) in cancer. Mechanisms, reversal using modulators of MDR and the role of MDR modulators in influencing the pharmacokinetics of anticancer drugs

In recent years, there has been an increased understanding of P-glycoprotein (P-GP)-mediated pharmacokinetic interactions. In addition, its role in modifying the bioavailability of orally administered drugs via induction or inhibition has been also been demonstrated in various studies. This overview presents a background on some of the commonly documented mechanisms of multidrug resistance (MDR), reversal using modulators of MDR, followed by a discussion on the functional aspects of P-GP in the context of the pharmacokinetic interactions when multiple agents are coadministered. While adverse pharmacokinetic interactions have been documented with first and second generation MDR modulators, certain newer agents of the third generation class of compounds have been less susceptible in eliciting pharmacokinetic interactions. Although the review focuses on P-GP and the pharmacology of MDR reversal using MDR modulators, relevance of these drug transport proteins in the context of pharmacokinetic implications (drug absorption, distribution, clearance, and interactions) will also be discussed.

Secondary structure of the 5'-region of PGY1/MDR1 mRNA

In order to identify the optimal target sites for antisense oligonucleotides in the human multiple drug resistance mRNA, the secondary structure of the 5'-terminal part of this mRNA (nucleotides 1-678) was investigated. By using results of probing with ribonucleases T1, ONE and V1 and results of computer simulations, a model of the 5'-region of the PGY1/MDR1 mRNA was built. The molecule is formed by three major domains comprising several hairpins separated by single-stranded fragments. The predicted single-stranded regions of the PGY1/MDR1 mRNA efficiently bind complementary oligonucleotides.

Quinine improves results of intensive chemotherapy (IC) in myelodysplastic syndromes (MDS) expressing P-glycoprotein (PGP). Updated results of a randomized study. Groupe Français des Myélodysplasies (GFM) and Groupe GOELAMS

We designed a randomized trial of IC with or without quinine, an agent capable of reverting the multidrug resistance (mdr) phenotype, in patients aged < or = 65 years with high risk MDS. Patients were randomized to receive Mitoxantrone 12 mg/m2/d d2-5 + AraC 1 g/m2/12 h d1-5, with (Q+) or without (Q-) quinine (30 mg/kg/day). 131 patients were included. PGP expression analysis was successfully made in 91 patients and 42 patients (46%) had positive PGP expression. In PGP positive cases, 13 of the 25 (52%) patients who received quinine achieved CR, as compared to 3 of the 17 (18%) patients treated with chemotherapy alone (p = 0.02). In PGP negative cases, the CR rate was 35% and 49%, respectively in patients who received quinine or chemotherapy alone (difference not significant). In the 42 PGP positive patients, median Kaplan-Meier (KM) survival was 13 months in patients allocated to the quinine group, and 8 months in patients treated with chemotherapy alone (p = 0.01). In PGP negative patients, median KM survival was 14 months in patients allocated to the quinine group, and 14 months in patients treated with chemotherapy alone. Side effects of quinine mainly included vertigo and tinnitus that generally disappeared with dose reduction. Mucositis was significantly more frequently observed in the quinine group. No life threatening cardiac toxicity was observed. In conclusion, results of this randomized study show that quinine increases the CR rate and survival in PGP positive MDS cases treated with IC. The fact that quinine had no effect on the response rate and survival of PGP negative MDS suggests a specific effect on PGP mediated drug resistance rather than, for instance, a simple effect on the metabolism of Mitoxantrone and/or AraC.

Quinine improves the results of intensive chemotherapy in myelodysplastic syndromes expressing P glycoprotein: results of a randomized study

Intensive chemotherapy produces a lower complete remission (CR) rate in the myelodysplastic syndromes (MDS) than in de novo acute myeloid leukaemia (AML), possibly due in part to a higher incidence of P glycoprotein (PGP) expression in MDS blast cells. We designed a randomized trial of intensive chemotherapy with or without quinine, an agent capable of reverting the multidrug resistance (mdr) phenotype, in patients aged < or = 65 years with high-risk MDS. Patients were randomized to receive mitoxantrone 12 mg/m2/d days 2-5 + AraC 1 g/m2/12 h days 1-5, with (Q+) or without (Q-) quinine (30 mg/kg/d). 131 patients were included. PGP expression analysis was successful in 91 patients. In the 42 PGP-positive cases, 13/25 (52%) patients in the Q+ group achieved CR, compared to 3/17 (18%) patients in the Q- group (P = 0.02) and median Kaplan-Meier survival was 13 months in the Q+ group, and 8 months in the Q- group (P = 0.01). No life-threatening toxicity was observed with quinine. In conclusion, the results of this randomized study show that quinine increases the CR rate and survival in PGP-positive MDS cases treated with intensive chemotherapy.

Selective mitomycin C and cyclophosphamide induction of apoptosis in differentiating B lymphocytes compared to T lymphocytes in vivo

Differentiating B and T lymphocytes differ in sensitivity to a number of environmental toxins and anticancer agents. B lymphocytes are susceptible and T lymphocytes resistant to killing by cyclophosphamide (Cy) metabolites capable of forming DNA interstrand cross-links. However, the mechanisms responsible for the rapid killing and loss of bursal-resident B lymphocytes are unknown. Therefore, we investigated the cellular mechanisms of selective toxicity of two cross-linking drugs, mitomycin C (MMC) and Cy, towards differentiating B and T lymphocyte populations using the chicken embryo model system. Viability of bursal-resident B lymphocytes (bursacytes) decreased starting at 5 h post exposure (PE) to MMC, and was maximally reduced by 71.6% by 10 h PE at the highest dose examined (9.0 micrograms MMC/g). Dose-dependent increases in the percentage of apoptotic bursacytes were observed as early as 5 h PE, and increased to 72% by 10 h PE. This was accompanied by reductions in bursacyte numbers. Cy also induced apoptosis in bursacytes. In contrast, thymus-resident lymphocytes (thymocytes) were much more resistant to the toxic effects of MMC and Cy. Viability of thymocytes was reduced by only 10% in the 9.0 micrograms/g MMC treatment group. In addition, the percentage of thymocytes engaged in apoptosis was much lower than that for bursacytes. MMC induced modest cell cycle inhibition in bursacytes and thymocytes. These data strongly suggest that MMC and Cy-induced diferential toxicity involves primarily early and extensive triggering of apoptosis in differentiating B lymphocytes, leading to rapid reduction of lymphocyte numbers in the embryonic bursa.

Modulation of sensitivity to mitomycin C and a dithiol analogue by tempol in non-small-cell lung cancer cell lines under hypoxia

We examined the mechanisms involved in the bioactivation of mitomycin C (MMC) and a newly developed MMC analogue: 7-N-(2-([2-(gamma-L-glutamylamino)ethyl]dithio)ethyl)mitomycin C, KW-2149, in non-small-cell lung cancer (NSCLC) cell lines under aerobic and hypoxic conditions. To investigate these mechanisms, we used MMC-resistant non-small-cell lung cancer cell lines (PC-9/MC4) that had been established in our laboratory from the parent PC-9 cell line by continuous exposure to MMC. We previously reported that the MMC-resistant cell line (PC-9/MC4) was poor in NAD(P)H dehydrogenase (quinone) activity and approximately 6-fold more resistant than the parent cells (PC-9) to MMC on 2-h exposure under aerobic conditions. In this study, the subline PC-9/MC4 was 6.7-fold more resistant to MMC than PC-9, the parent cell line, under aerobic conditions, and 5.2-fold more resistant under hypoxic conditions after 2-h exposure to MMC. However, on co-incubation with tempol, an inhibitor of the one-electron reduction pathway, the sensitivity of PC-9/MC4 to MMC was impaired under hypoxic conditions, but the impairment was not evident under aerobic conditions. KW-2149, the newly developed MMC analogue, was cytotoxic for both PC-9/MC4 and PC-9 cells, and the sensitivity of both cell lines to KW-2149 was not changed by exposure to hypoxic conditions or by coincubation with tempol. There were no significant differences in the intracellular uptake of MMC and the activities of cytosolic detoxification enzymes between the PC-9 and PC-9/MC4 cell lines. These results support the hypothesis that the one-electron reduction pathway plays a partial role in the bioactivation of MMC, but not of KW-2149, and that KW-2149 is excellent at circumventing resistance to MMC in NSCLC.

Reversal of doxorubicin resistance and catalytic neutralization of lysosomes by a lipophilic imidazole

A number of lipophilic nitrogenous bases, designed to act as membrane-active, catalytic proton transfer agents, were tested for their ability to neutralize the acidity of lysosomes, a model for other acidic intracellular vesicles involved in drug sorting. The most successful of these, an imidazole 1, caused a 1.7 unit rise in lysosomal pH of RAW cells at 100 microM, compared to a 0.2 and 1.4 unit rise for ammonium chloride at 100 microM and 10 mM, respectively. Compound 1 also exhibited potent reversal of doxorubicin (DOX) resistance in the HCT116-VM46 cell line by a factor of 14 over the sensitive strain, and superior to that of widely used verapamil (VRP) by a factor of 1.75 at 20 microM. It also has antiviral properties, and potential applications in other lysosome-related areas such as immunotoxin potentiation and the control of bacterial toxins, immune response, prion replication, malaria and intralysosomal microorganisms.

Reversal agent inhibition of the multidrug resistance pump in human leukemic lymphoblasts

Multidrug resistant cancer cells of the MDR-1 phenotype utilize an ATP-dependent pump to excrete toxic drugs. Rhodamine 123 (R123) is a fluorescent substrate of the MDR pump. An assay for the ATP-dependent initial efflux of R123 from CEM/VLB100 human leukemic lymphoblasts has been developed. The MDR-1 cells were treated with a reversal agent and preloaded with 40.0 nM R123 in buffer at 30 degrees C that contained sodium azide and 2-deoxyglucose. The cells were rinsed with cold buffer and resuspended in L-glutamine/glucose solution at 23 degrees C. The cell suspension was passed through a filter and R123 in the filtrate was detected at 2-s intervals by fluorescence. Efflux of R123 was inhibited by the reversal agents amiodarone, cyclosporin A, Ro11-2933 (DMDP), quinidine, and the optical isomers of propranolol. The MDR pump is stereospecific for the (R)-diastereomer quinidine; however, the (S)-diastereomer quinine is a relatively weak inhibitor of the pump. Cyclosporin A was the most potent inhibitor tested against the efflux of R123 by the MDR pump.

Effect of cyclosporine on colchicine secretion by a liver canalicular transporter studied in vivo

The multidrug resistance transport protein is a normal constituent of the liver canalicular membrane, although its function has not been defined in vivo. Colchicine, a multidrug resistance substrate, is eliminated mainly by the liver. Cyclosporine reverses multidrug resistance in vitro, presumably by inhibiting the multidrug resistance transporter. This study assesses biliary colchicine elimination and the effect of cyclosporine on this process. After cyclosporine administration biliary colchicine clearance decreased from 11.6 +/- 0.8 to 2.2 +/- 0.4 ml/min.kg (p less than 0.05), and the colchicine bile/plasma ratio decreased from 166 +/- 9 to 38 +/- 5 (p less than 0.05). Cremophor EL (a cyclosporine vehicle) transiently inhibited biliary colchicine clearance and colchicine bile/plasma ratio, but to a much smaller extent than cyclosporine in vehicle. Biliary cyclosporine clearance was 0.122 and 0.024 ml/min.kg after bolus doses of 2 or 10 mg/kg intravenously, respectively. Cyclosporine bile/plasma ratio was 1.3 to 5.2. When cyclosporine was given 16 hr before colchicine infusion, biliary colchicine clearance decreased 39% (p less than 0.05), and colchicine bile/plasma ratio decreased 51% (p less than 0.05). Thus colchicine is actively secreted into bile and will be useful in the study of the multidrug transporter in vivo. Cyclosporine profoundly inhibits colchicine secretion into bile but is itself mainly metabolized rather than secreted. If competition for a common carrier is the basis for the interaction, then cyclosporine represents a drug that binds to but is not transported by the canalicular transporter.