title: An antimitotic and antivascular agent BPR0L075 overcomes multidrug resistance and induces mitotic catastrophe in paclitaxel-resistant ovarian cancer cells.
abstract: Paclitaxel plays a major role in the treatment of ovarian cancer; however, resistance to paclitaxel is frequently observed. Thus, new therapy that can overcome paclitaxel resistance will be of significant clinical importance. We evaluated antiproliferative effects of an antimitotic and antivascular agent BPR0L075 in paclitaxel-resistant ovarian cancer cells. BPR0L075 displays potent and broad-spectrum cytotoxicity at low nanomolar concentrations (IC50 = 2-7 nM) against both parental ovarian cancer cells (OVCAR-3, SKOV-3, and A2780-1A9) and paclitaxel-resistant sublines (OVCAR-3-TR, SKOV-3-TR, 1A9-PTX10), regardless of the expression levels of the multidrug resistance transporter P-gp and class III β-tubulin or mutation of β-tubulin. BPR0L075 blocks cell cycle at the G2/M phase in paclitaxel-resistant cells while equal concentration of paclitaxel treatment was ineffective. BPR0L075 induces cell death by a dual mechanism in parental and paclitaxel-resistant ovarian cancer cells. In the parental cells (OVCAR-3 and SKOV-3), BPR0L075 induced apoptosis, evidenced by poly(ADP-ribose) polymerase (PARP) cleavage and DNA ladder formation. BPR0L075 induced cell death in paclitaxel-resistant ovarian cancer cells (OVCAR-3-TR and SKOV-3-TR) is primarily due to mitotic catastrophe, evidenced by formation of giant, multinucleated cells and absence of PARP cleavage. Immunoblotting analysis shows that BPR0L075 treatment induced up-regulation of cyclin B1, BubR1, MPM-2, and survivin protein levels and Bcl-XL phosphorylation in parental cells; however, in resistant cells, the endogenous expressions of BubR1 and survivin were depleted, BPR0L075 treatment failed to induce MPM-2 expression and phosphorylation of Bcl-XL. BPR0L075 induced cell death in both parental and paclitaxel-resistant ovarian cancer cells proceed through caspase-3 independent mechanisms. In conclusion, BPR0L075 displays potent cytotoxic effects in ovarian cancer cells with a potential to overcome paclitaxel resistance by bypassing efflux transporters and inducing mitotic catastrophe. BPR0L075 represents a novel microtubule therapeutic to overcome multidrug resistance and trigger alternative cell death by mitotic catastrophe in ovarian cancer cells that are apoptosis-resistant.
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, Texas, United States of America.
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Wang
authors.forename: Erxi
authors.initials: E
authors.lastname: Wu
authors.forename: Jun
authors.initials: J
authors.lastname: Wu
authors.forename: Tian-Li
authors.initials: TL
authors.lastname: Wang
authors.forename: Hsing-Pang
authors.initials: HP
authors.lastname: Hsieh
authors.forename: Xinli
authors.initials: X
authors.lastname: Liu
mesh_terms: D050256:Antimitotic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D056744:Cyclin B1 / Q000235:genetics / Q000378:metabolism; D003603:Cytotoxins / Q000494:pharmacology*; D053938:DNA Fragmentation; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm / Q000187:drug effects* / Q000235:genetics; D005260:Female; D000072278:Forkhead Box Protein M1; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics / Q000378:metabolism; D008938:Mitosis / Q000187:drug effects* / Q000235:genetics; D010053:Ovary / Q000378:metabolism* / Q000473:pathology; D017239:Paclitaxel / Q000494:pharmacology; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D000077022:Survivin; D051020:bcl-X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: C488735:6-methoxy-3-(3',4',5'-trimethoxybenzoyl)-1H-indole; D050256:Antimitotic Agents; C494811:BCL2L1 protein, human; C107489:BIRC5 protein, human; D056744:Cyclin B1; D003603:Cytotoxins; C107585:FOXM1 protein, human; D000072278:Forkhead Box Protein M1; D051858:Forkhead Transcription Factors; D007211:Indoles; D051034:Inhibitor of Apoptosis Proteins; D000077022:Survivin; D051020:bcl-X Protein; D011065:Poly(ADP-ribose) Polymerases; C584277:BUB1 protein, human; D017346:Protein Serine-Threonine Kinases; D017239:Paclitaxel