Mycoplasma Infection Mediates Sensitivity of Multidrug-Resistant Cell Lines to Tiopronin: A Cautionary Tale

Chemotherapy is a mainstay of cancer treatment. Due to increased drug resistance and the severe side effects of currently used therapeutics, new candidate compounds are required for improvement of therapy success. Shikonin, a natural naphthoquinone, was used in traditional Chinese medicine for the treatment of different inflammatory diseases and recent studies revealed the anticancer activities of shikonin. We found that shikonin has strong cytotoxic effects on 15 cancer cell lines, including multidrug-resistant cell lines. Transcriptome-wide mRNA expression studies showed that shikonin induced genetic pathways regulating cell cycle, mitochondrial function, levels of reactive oxygen species, and cytoskeletal formation. Taking advantage of the inherent fluorescence of shikonin, we analyzed its uptake and distribution in live cells with high spatial and temporal resolution using flow cytometry and confocal microscopy. Shikonin was specifically accumulated in the mitochondria, and this accumulation was associated with a shikonin-dependent deregulation of cellular Ca2+and ROS levels. This deregulation led to a breakdown of the mitochondrial membrane potential, dysfunction of microtubules, cell-cycle arrest, and ultimately induction of apoptosis. Seeing as both the metabolism and the structure of mitochondria show marked differences between cancer cells and normal cells, shikonin is a promising candidate for the next generation of chemotherapy.

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Examination by laser scanning confocal fluorescence imaging microscopy of the subcellular localisation of anthracyclines in parent and multidrug resistant cell lines

British Journal of Cancer ◽

10.1038/bjc.1993.244 ◽

1993 ◽

Vol 67 (6) ◽

pp. 1316-1323 ◽

Cited By ~ 91

Author(s):

HM Coley ◽

WB Amos ◽

PR Twentyman ◽

P Workman

Keyword(s):

Fluorescence Imaging ◽

Cell Lines ◽

Laser Scanning ◽

Multidrug Resistant ◽

Resistant Cell ◽

Subcellular Localisation ◽

Confocal Fluorescence ◽

Fluorescence Imaging Microscopy ◽

Confocal Fluorescence Imaging

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Structure and expression of the human MDR (P-glycoprotein) gene family.

Molecular and Cellular Biology ◽

10.1128/mcb.9.9.3808 ◽

1989 ◽

Vol 9 (9) ◽

pp. 3808-3820 ◽

Cited By ~ 189

Author(s):

J E Chin ◽

R Soffir ◽

K E Noonan ◽

K Choi ◽

I B Roninson

Keyword(s):

Gene Family ◽

Cell Lines ◽

Efflux Pump ◽

Expression Patterns ◽

Multidrug Resistant ◽

Resistant Cell ◽

Mdr1 Gene ◽

Glycoprotein Gene ◽

P Glycoprotein ◽

Mdr Genes

The human MDR (P-glycoprotein) gene family is known to include two members, MDR1 and MDR2. The product of the MDR1 gene, which is responsible for resistance to different cytotoxic drugs (multidrug resistance), appears to serve as an energy-dependent efflux pump for various lipophilic compounds. The function of the MDR2 gene remains unknown. We have examined the structure of the human MDR gene family by Southern hybridization of DNA from different multidrug-resistant cell lines with subfragments of MDR1 cDNA and by cloning and sequencing of genomic fragments. We have found no evidence for any other cross-hybridizing MDR genes. The sequence of two exons of the MDR2 gene was determined from genomic clones. Hybridization with single-exon probes showed that the human MDR1 gene is closely related to two genes in mouse and hamster DNA, whereas MDR2 corresponds to one rodent gene. The human MDR locus was mapped by field-inversion gel electrophoresis, and both MDR genes were found to be linked within 330 kilobases. The expression patterns of the human MDR genes were examined by enzymatic amplification of cDNA. In multidrug-resistant cell lines, increased expression of MDR1 mRNA was paralleled by a smaller increase in the levels of MDR2 mRNA. In normal human tissues, MDR2 was coexpressed with MDR1 in the liver, kidney, adrenal gland, and spleen. MDR1 expression was also detected in colon, lung, stomach, esophagus, muscle, breast, and bladder.

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