Action of calcium antagonists on multidrug resistant cells: Specific cytotoxicity independent of increased cancer drug accumulation

doi:10.1016/0006-2952(87)90139-0

Biochemical Pharmacology

Volume 36, Issue 13, 1 July 1987, Pages 2115-2123

https://doi.org/10.1016/0006-2952(87)90139-0 Get rights and content

Abstract

Previous studies have shown that calcium channel blockers can overcome, at least partially, multidrug resistance (MDR). This study was undertaken to attempt to determine the mechanisms whereby these agents bring about this effect. Their influence on the uptake and retention of several cancer drugs and on the toxic actions of these compounds was assessed employing MDR cell lines from several species. The wild-type drug sensitive parent cells proved to be more susceptible than the multidrug resistant variants to the effects of calcium channel blockers on cancer drug accumulation. This was shown for verapamil, nifedipine and the calmodulin inhibitor trifluoperazine acting on human, mouse and Chinese hamster ovary (CHO) cell lines. The enhancement of drug accumulation by calcium antagonists was similar to that caused by non-ionic detergents. Furthermore, verapamil was unable to alter ⁴⁵Ca²⁺ accumulation in sensitive or resistant cells, suggesting that these agents act in a calcium-independent manner. Verapamil accumulation in multidrug resistant cells was reduced compared to sensitive cells. In spite of this reduced accumulation, however, verapamil alone was much more toxic to multidrug resistant cells than to the sensitive cells. This suggests that calcium channel blockers are specifically toxic to MDR cells by virtue of an interaction with the MDR cell surface distinct from that involved in promoting cellular accumulation.

References (36)

J.R. Riordan et al.
Pharmac. Ther.
(1985)
P. Gros et al.
Cell
(1986)
C-J. Chen et al.
Cell
(1986)
T. Tsuruo et al.
Biochem. Pharmac.
(1982)
B. Weiss et al.
Biochem. Pharmac.
(1982)
D. Kessel et al.
Biochem. Pharmac.
(1984)
R.J. Sharma et al.
Biochem. biophys. Res. Commun.
(1981)
W.T. Beck
Adv. Enzyme Regulat.
(1984)
P.R. Twentyman et al.
Int. J. Radiat. Oncol. Biol. Phys.
(1986)
V. Ling et al.
Cancer Treat. Rep.
(1963)

N.T. Bech-Hansen et al.

J. cell. Physiol.

(1976)

N. Kartner et al.

Science

(1983)

J.R. Riordan et al.

Nature. Lond.

(1985)

A. Fojo et al.

Cancer Res.

(1985)

S.G. Pradhan et al.

Oncology

(1984)

A.M. Rogan et al.

Science

(1984)

T. Tsuruo et al.

Cancer Res.

(1981)

T. Tsuruo et al.

Cancer Res.

(1983)

Cited by (150)

Discovery of 2,5-disubstituted furan derivatives featuring a benzamide motif for overcoming P-glycoprotein mediated multidrug resistance in MCF-7/ADR cell
2023, European Journal of Medicinal Chemistry
P-glycoprotein (P-gp) is one of the drug efflux transporters that triggers multidrug resistance (MDR) in cells. Herein, by utilizing the strategies of active skeleton splicing and structural optimization on the lead compound 5 m, a total of 50 novel 2,5-disubstituted furan derivatives were designed, synthesized, and screened for P-gp inhibitory activity. The structure-activity relationship analysis enabled the identification of an important pharmacophore N-phenylbenzamide, which resulted in the discovery of a promising drug lead compound Ⅲ-8. Ⅲ-8 possesses broad-spectrum reversal activity and low toxicity in MCF-7/ADR cells. Western blot and Rh123 accumulation assay demonstrated that Ⅲ-8 displayed the reversal activity by inhibiting P-gp efflux. Molecular docking analysis indicated a potent affinity of Ⅲ-8 to P-gp by forming H-bond interactions with residues Asn 721 and Met 986. Ⅲ-8 was determined to be a highly effective and safe P-gp inhibitor in an MCF-7/ADR xenograft mouse model.
Targeting breast cancer resistance protein (BCRP/ABCG2): Functional inhibitors and expression modulators
2022, European Journal of Medicinal Chemistry
Citation Excerpt :
Later, in 1982, it was shown that colchicine resistant cell lines had increased sensitivity to taxol, verapamil and other calcium channel blockers [45–47]. This sensitivity depended on P-gp overexpression in a mechanism unrelated to inhibition [48]. In 2003, the mechanism of CS triggered by verapamil was described as being mediated by reactive oxygen species in response to the high ATP demand [49].
The primary source of failure of cancer therapies is multidrug resistance (MDR), which can be caused by different mechanisms, including the overexpression of ABC transporters in cancer cells. Among the 48 human ABC proteins, the breast cancer resistance protein (BCRP/ABCG2) has been described as a pivotal player in cancer resistance. The use of functional inhibitors and expression modulators is a promising strategy to overcome the MDR caused by ABCG2. Despite the lack of clinical trials using ABCG2 inhibitors, many compounds have already been discovered. This review presents an overview about various ABCG2 inhibitors that have been identified, discussing some chemical aspects and the main experimental methods used to identify and characterize the mechanisms of new inhibitors. In addition, some biological requirements to pursue preclinical tests are described. Finally, we discuss the potential use of ABCG2 inhibitors in cancer stem cells (CSC) for improving the objective response rate and the mechanism of ABCG2 modulators at transcriptional and protein expression levels.
Exploiting the metabolic energy demands of drug efflux pumps provides a strategy to overcome multidrug resistance in cancer
2021, Biochimica et Biophysica Acta - General Subjects
Citation Excerpt :
The shortfall in ATP availability may manifest as reduced cell viability and P-gp expressing cells are known to display a fragility to certain compounds that stimulate ATP consumption. This phenomenon is referred to as collateral sensitivity and exemplified by the ability of verapamil to kill multidrug resistant cells at a higher potency than the drug-sensitive parental cells [35,36]. The underlying mechanism remains elusive; although it is postulated that verapamil “traps” P-gp in a futile, and ATP demanding, transport cycle that ultimately leads to cell damage [37].
P-glycoprotein (P-gp) is a prevalent resistance mediator and it requires considerable cellular energy to ensure ATP dependent efflux of anticancer drugs. The glycolytic pathway generates the majority of catabolic energy in cancer cells; however, the high rates of P-gp activity places added strain on its inherently limited capacity to generate ATP. This is particularly relevant for compounds such as verapamil that are believed to trap P-gp in a futile transport process that requires continuing ATP consumption. Ultimately, this leads to cell death and the hypersensitivity of resistant cells to verapamil is termed collateral sensitivity.
We show that the addition of verapamil to resistant cells produces a prominent reduction in ATP levels that supports the idea of disrupted energy homeostasis. Even in the absence of verapamil, P-gp expressing cells display near maximal rates of glycolysis and oxidative phosphorylation, which prevents an adequate response to the demand for ATP to sustain transport activity. Moreover, the near perpetually maximal rate of oxidative phosphorylation in the presence of verapamil resulted in elevated levels of reactive oxygen species that affect cell survival and underscore collateral sensitivity.
Our results demonstrate that the strained metabolic profiles of P-gp expressing resistant cancer cells can be overwhelmed by additional ATP demands.
Consequently, collateral sensitising drugs may overcome the resistant phenotype by exploiting, rather than inhibiting, the energy demanding activity of pumps such as P-gp.
Identification of dual DNA-PK MDR1 inhibitors for the potentiation of cytotoxic drug activity
2014, Biochemical Pharmacology
Citation Excerpt :
Compounds that interact with MDR1 can do so by different mechanisms. Verapamil is known to modulate drug resistance by acting as a competitive MDR1 substrate [36]. Interestingly, NU7441 has similar growth inhibitory activity in the sensitive and resistant cells and there was no observed reduction in intracellular levels of NU7441 over time (Figs. 2(d) and 6).
Inhibition of DNA repair is an attractive therapeutic approach to enhance the activity of DNA-damaging anticancer chemotherapeutic agents. Similarly, blockade of the multidrug-resistance protein 1 (MDR1) can overcome efflux-mediated resistance. DNA-dependent protein kinase (DNA-PK) is essential for the non-homologous end-joining DNA repair pathway. NU7441 is a potent DNA-PK inhibitor (IC₅₀ = 14 nM) that is used widely to study the effects of DNA-PK inhibition in vitro. In growth inhibition studies, 1 μM NU7441 sensitised vincristine-resistant CCRF-CEM VCR/R leukaemia cells (1200-fold resistant) to a range of MDR1 substrates, including doxorubicin (8-fold, p = 0.03), vincristine (14-fold, p = 0.01) and etoposide (63-fold, p = 0.02), compared with 1.4-fold (p = 0.02), 2.2-fold (p = 0.04) and 3.6-fold (p = 0.01) sensitisation, respectively, in parental CCRF-CEM cells. This difference in NU7441 sensitivity was confirmed in another two parental and MDR1-overexpressing cell line pairs. A doxorubicin fluorescence assay showed that in MDR1-overexpressing canine kidney MDCKII-MDR1 cells, 1 μM NU7441 increased doxorubicin nuclear fluorescence 16-fold. NU7441 and 3 structurally related compounds (NU7742 (an NU7441 analogue that does not inhibit DNA-PK – IC₅₀ > 10 μM), DRN1 (DNA-PK-inhibitory atropisomeric NU7441 derivative – IC₅₀ = 2 nM) and DRN2 (DNA-PK non-inhibitory atropisomeric NU7441 derivative - IC₅₀ = 7 μM)) all increased intracellular vincristine accumulation in the CCRF-CEM VCR/R cells to a level similar to verapamil, as measured by LC–MS. This paper demonstrates that NU7441 is a dual DNA-PK and MDR1 inhibitor, and this extends the therapeutic potential of the compound when used in combination with MDR substrates.
Collateral sensitivity as a strategy against cancer multidrug resistance
2012, Drug Resistance Updates
While chemotherapy remains the most effective treatment for disseminated tumors, acquired or intrinsic drug resistance accounts for approximately 90% of treatment failure. Multidrug resistance (MDR), the simultaneous resistance to drugs that differ both structurally and mechanistically, often results from drug efflux pumps in the cell membrane that reduce intracellular drug levels to less than therapeutic concentrations. Expression of the MDR transporter P-glycoprotein (P-gp, MDR1, ABCB1) has been shown to correlate with overall poor chemotherapy response and prognosis. This review will focus on collateral sensitivity (CS), the ability of compounds to kill MDR cells selectively over the parental cells from which they were derived. Insights into CS may offer an alternative strategy for the clinical resolution of MDR, as highly selective and potent CS agents may lead to drugs that are effective at MDR cell killing and tumor resensitization. Four main mechanistic hypotheses for CS will be reviewed, followed by a discussion on quantitative and experimental evaluation of CS.
P-glycoprotein (ABCB1) modulates collateral sensitivity of a multidrug resistant cell line to verapamil
2009, Archives of Biochemistry and Biophysics
Citation Excerpt :
This latter phenomenon has been known as “collateral sensitivity” of drug-resistant cells expressing high levels of P-gp1 [11]. Several studies have now demonstrated the collateral sensitivity of P-gp1-overexpressing, drug-resistant cell lines to verapamil, non-ionic detergents and steroids [12–14]. Moreover a correlation between certain agents that affect the physical property and fluidity of the membrane and collateral sensitivity was shown to be dependent on P-gp1 expression levels in drug-resistant cells [11,15,16].
P-glycoprotein (or P-gp1, ABCB1) expression in tumor cells is causative of multidrug resistance through the active efflux of drugs across the cell membrane. However, the over-expression of P-glycoprotein in some tumor cells has been associated with increased sensitivity, or “collateral sensitivity”, of multidrug resistant cells to specific drugs, including the calcium channel blocker verapamil. We previously demonstrated that collateral sensitivity to verapamil correlates with the effect of this drug on P-gp1 ATPase, and is reversed by inhibitors of P-gp1 ATPase (e.g., PSC 833 and Ivermectin). In this report, we expand on our earlier study and demonstrate that P-gp1 expression in drug-resistant cells modulates collateral sensitivity. Using P-gp1-specific siRNA, P-gp1 expression in the multidrug resistant CH^RC5 cells was significantly down-regulated beginning on day 2 post-transfection of siRNA. Furthermore, down-regulation of P-gp1 led to increased sensitivity of CH^RC5 cells to paclitaxel and doxorubicin, but not to cis-platinum, due to inhibition of P-gp1 drug efflux pump. Down-regulation of P-gp1 expression completely reversed collateral sensitivity to verapamil. Moreover, known inhibitors of ETC, rotenone and antimycin A which cause an increase in reactive oxygen species, synergized with verapamil-induced collateral sensitivity leading to increased cell death as determined by MTT cell survival assay. Similarly, the addition of hydrogen peroxide also synergized with verapamil. Taken together, the results of this study demonstrate a direct link between P-gp1 expression and collateral sensitivity of drug-resistant cells, possibly due to an increase in reactive oxygen species.

View all citing articles on Scopus

View full text

Action of calcium antagonists on multidrug resistant cells: Specific cytotoxicity independent of increased cancer drug accumulation

Abstract

Pharmac. Ther.

Cell

Cell

Biochem. Pharmac.

Biochem. Pharmac.

Biochem. Pharmac.

Biochem. biophys. Res. Commun.

Adv. Enzyme Regulat.

Int. J. Radiat. Oncol. Biol. Phys.

Cancer Treat. Rep.

J. cell. Physiol.

Science

Nature. Lond.

Cancer Res.

Oncology

Science

Cancer Res.

Cancer Res.