Noninvasive Detection of Lentiviral-Mediated Choline Kinase Targeting in a Human Breast Cancer Xenograft

Abstract

Elevated phosphocholine (PC) and total choline (tCho) metabolites are widely established characteristics of most cancer cells, including breast cancer. Effective silencing of choline kinase (chk), the enzyme that converts choline to PC, is associated with reduced tumor growth. The functional importance and down-regulation of chk using RNA interference has been previously established. Here, we report on the preclinical evaluation of lentiviral vector-mediated downregulation of chk using short hairpin RNA (shRNA) in established tumors derived from human breast cancer cells. Concentrated lentivirus expressing shRNA against chk was injected i.v. in the tail vein of MDA-MB-231 tumor-bearing female severe combined immunodeficient mice. Transduction efficiency in cells and tumors in vivo was assessed optically by enhanced green fluorescent protein expression and additionally from chk mRNA and protein levels. An 80% reduction in chk mRNA and protein was achieved following f90% transduction efficiency in cells. After transduction with chkshRNA, 1 H magnetic resonance spectroscopy (MRS) of cell and tumor extracts showed decreases in PC and tCho levels (P < 0.01 and 0.05, respectively) in comparison with controls. PC levels were monitored noninvasively by 31 P MRS in tumors and by 1 H MRS in cell and tumor tissue extracts. Noninvasive 31 P MR spectra of chk-shRNA-transduced tumors in vivo showed lower PC and phosphomonoester levels that were associated with reduced tumor growth and proliferation. This study shows the use of lentiviral vectors to target chk in a human breast cancer xenograft and noninvasive MRS detection of this targeting. [Cancer Res 2009;69(8):3464-71]

Alterations of Choline Phospholipid Metabolism in Endometrial Cancer Are Caused by Choline Kinase Alpha Overexpression and a Hyperactivated Deacylation Pathway

“…Although our approach illustrates tissue heterogeneity, the use of microdissection techniques and larger samples size may reduce the variation observed in the presented results. In a number of studies, CHKA has been shown to mediate cellular proliferation, transformation, and carcinogenesis, and mediation of this target using siRNA and smallmolecule inhibitors suggests inhibition of tumor growth (11,16,18,40,41). As indicated, we further observed in clinical samples and endometrial cancer cell lines, a significant increase in the mRNA expression of enzymes of the phosphatidylcholine deacylation pathway; GPCPD1, LYPLA1, and LYPLA2.…”

“…Furthermore, overexpression of CHKA (6)(7)(8) and abundance of choline metabolites (13)(14)(15) have been shown to be prognostic in a number of cancers including prostate, breast, lung, and ovarian cancer. More recently inhibition of CHKA, both by shRNA and small-molecule inhibitors, has been shown to have both an antimitogenic and antiproliferative effects in vitro and in vivo (16)(17)(18)(19)(20)(21).…”

Pharmacodynamic and pharmacogenomic study of the nanoparticle conjugate of camptothecin CRLX101 for the treatment of cancer

“…Our results are in agreement with studies that suggested a positive correlation between Ki-67 score and shorter survival. 40,41 We have previously shown that CRLX101 treatment inhibited expression of CaIX in a tumor sections. Also the expression of CaIX was lower in the sample from the patient with longer survival duration as compared to the other.…”

Changes in Gene Transcription Underlying the Aberrant Citrate and Choline Metabolism in Human Prostate Cancer Samples

“…The ChoCCs constitute important building blocks in cell membranes and are elevated, in several malignancies (8,9), including prostate cancer (10), due to altered phospholipid metabolism. When using gene therapy to silence the enzyme choline kinase converting Cho to PC, a reduction of cell proliferation and tumor growth was shown in breast cancer cell lines (11). The prostate is highly specialized for the production and secretion of citrate, which is used as an energy supply for sperm.…”