IND-2, a pyrimido[1″,2″:1,5]pyrazolo[3,4-b]quinoline derivative, circumvents multi-drug resistance and causes apoptosis in colon cancer cells

Abstract

Naturally occurring condensed quinolines have anticancer properties. In efforts to find active analogues, we designed and synthesized eight polycyclic heterocycles with a pyrimido[1”,2”:1,5]pyrazolo[3,4-b]quinoline framework (IND series). The compounds were evaluated for activity against colon (HCT-116 and S1-MI-80), prostate (PC3 and DU-145), breast (MCF-7 and MDAMB-231), ovarian (ov2008 and A2780), and hepatocellular (HepG2) cancer cells and against non-cancerous Madin Darby canine kidney (MDCK), mouse embryonic fibroblast (NIH/3T3), and human embryonic kidney cells (HEK293). IND-2, a 4-chloro-2-methyl pyrimido[1”,2”:1,5]pyrazolo[3,4-b]quinoline, exhibited more than tenfold selectivity and potent cytotoxic activity against colon cancer cells relative to the other cancer and non-cancer cells. With five additional colon cancer cell lines (HT-29, HCT-15, LS-180, LS-174, and LoVo), IND-2 had similar cytotoxicity and selectivity, and submicromolar concentrations caused changes in the morphology of HCT-116 and HCT-15 cells. IND-2 did not activate the transactivating function of the pregnane X receptor (PXR), indicating that it does not induce PXR-regulated ABCB1 or ABCG2 transporters. Indeed, IND-2 was not a substrate of ABCB1 or ABCG2, and it induced cytotoxicity in HEK293 cells overexpressing ABCB1 or ABCG2 to the same extent as in normal HEK293 cells. IND-2 was cytotoxic to resistant colon carcinoma S1-MI-80 cells, approximately three- and fivefold more than SN-38 and topotecan, respectively. In HCT-116 colon cancer cells, IND-2 produced concentration-dependent changes in mitochondrial membrane potential, leading to apoptosis, and sub-micromolar concentrations caused chromosomal DNA fragmentation. These findings suggest that, by increasing apoptosis, IND-2 has potential therapeutic efficacy for colorectal cancer.

Pyrimido[1″,2″:1,5]pyrazolo[3,4-b]quinolines: Novel compounds that reverse ABCG2-mediated resistance in cancer cells

“…One compound, IND-2, selectively inhibited the growth of colon cancer cells (HCT-116, S1-MI-80, HT-29, HCT-15, LS-180, LS-174, and Lovo) at submicromolar concentrations. Although the other IND derivatives did not display significant efficacy as anticancer compounds [15], most of the 2-methylpyrimido [1″,2″: 1,5]pyrazolo [3,4-b]quinolines incorporated structural features deemed significant for reversing MDR, such as a polycyclic aromatic ring, protonable nitrogen, H-bond donors/acceptors and lipophilicity [16]. The presence of key structural features required for MDR reversal activity, with the lack of cytotoxicity (>50 μM) in Colon carcinoma cell lines, HCT-116, HCT-15, HT-29, Lovo, LS-180, LS-174, S1 (a clone of LS174T cells), and S1-M1-80 (resistant); prostatic cancer cell lines, DU-145 and PC-3; breast carcinoma cells, MDA-MB-231 and MCF-7; ovarian cancer cells, ov2008 and A2780; canine kidney MDCK cells; mouse fibroblast NIH/3T3 cells; human liver cells HepG2 [15], suggests that the 2-methylpyrimido [1″,2″: 1,5]pyrazolo [3,4-b]quinoline derivatives may have efficacy as MDR reversal compounds that could enhance the anticancer efficacy of traditional chemotherapeutics by interacting with ABCG2 transporters.…”

“…1 for their structures) were synthesized as previously described [15]. Doxorubicin (Dox), mitoxantrone (MX), 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), cisplatin, rifampicin, rhodamine 123, topotecan and dimethyl sulfoxide (DMSO) were purchased from Sigma Chemical Co. (St. Louis, MO).…”

“…Recently, we synthesized a novel series of eight 2-methylpyrimido [1″,2″: 1,5]pyrazolo [3,4-b]quinolines (IND-1 to IND-8) and determined their efficacy against multiple cancer cell lines [15]. One compound, IND-2, selectively inhibited the growth of colon cancer cells (HCT-116, S1-MI-80, HT-29, HCT-15, LS-180, LS-174, and Lovo) at submicromolar concentrations.…”

Combined isocyanide-based multi-component Ullmann-type reaction: an efficient access to novel nitrogen-containing pentacyclic compounds

“…2-Chloroquinoline-3-carbaldehyde was prepared according to the literature [41,42]. Melting points were measured with a Kofler hot stage apparatus and are uncorrected.…”

Synthesis and anticancer activity of novel tetrahydroquinoline and tetrahydropyrimidoquinoline derivatives

“…1) (Wall et al, 1966). It was reported also that a large number of quinolines and their derivatives possessed potent anticancer activity (Chen et al, 2005a(Chen et al, , b, 2006Zhao et al, 2005;Li et al, 2006;Tseng et al, 2008Tseng et al, , 2012Al-Said et al, 2011;Luniewski et al 2012;Karthikeyan et al, 2015). Several studies supported that the pyrimidine nucleus is an important pharmacophore in various antitumor agents (Ghorab et al, 1996(Ghorab et al, , 2006aGhorab, 2000;Abou El Ella et al, 2008;Liu et al, 2014;Shao et al, 2014;Kandeel et al, 2015;Ma et al, 2015).…”