Selective Killing of Leukemia and Lymphoma Cells Ectopically Expressing hCGβ by a Conjugate of Curcumin with an Antibody against hCGβ Subunit

Abstract

Objective: A variety of cancers ectopically express human chorionic gonadotropin beta (hCGβ). Patients harboring such cancers have poor prognosis and adverse survival. A recombinant chimeric antibody, cPiPP, exhibiting high affinity and specificity for hCGβ/hCG was engineered. This study was designed to determine whether this antibody alone or conjugated to curcumin can selectively kill tumor cells expressing hCGβ. Experimental Design: The study was carried out on MOLT-4 and U-937 cells expressing hCGβ and on peripheral blood leukocytes of acute myeloid leukemia (AML) patients. The anticancerous compound curcumin was conjugated to cPiPP. The binding of cPiPP and cPiPP-curcumin conjugate to cells was studied by flow cytometry and cytotoxicity by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), FACS with propidium iodide staining, trypan blue exclusion assay and microscopy. Results: The antibody did not impair the growth of MOLT-4 and U-937 cells in culture. Its conjugate with curcumin, however, was lethal to both cell lines. The immunoconjugate killed tumor cells bearing the CD33 marker of an AML patient expressing hCGβ but did not have a similar action on cells of another AML patient with the CD13 marker but who was negative for hCGβ. Conclusion: A humanized antibody against hCGβ linked to curcumin has potential for therapy of hCGβ-expressing tumors.

Perspectives on New Synthetic Curcumin Analogs and their Potential Anticancer Properties

“…Compared with Curcumin, its isoxazole (63) and pyrazole (61) derivatives exhibited increased cell growth inhibitory and pro-apoptotic effects in liver cancer HA22T/VGH cells as well as in other tumor cell types. The anti-tumor effects of isoxazole (63) and pyrazole (61) were not influenced by concomitant administration of Nacetylcysteine, as a source of -SH groups, or buthionine sulfoximine as an inhibitor of glutathione synthesis. Additionally treatment with Curcumin, but not with isoxazole (63) and pyrazole (61), significantly decreased the content of reduced glutathione in the HA22T/ VGH cells.…”

“…The anti-tumor effects of isoxazole (63) and pyrazole (61) were not influenced by concomitant administration of Nacetylcysteine, as a source of -SH groups, or buthionine sulfoximine as an inhibitor of glutathione synthesis. Additionally treatment with Curcumin, but not with isoxazole (63) and pyrazole (61), significantly decreased the content of reduced glutathione in the HA22T/ VGH cells. Isoxazole (63) and pyrazole (61) lacked the ability of the parent compound to sensitize the HA22T/VGH cells to cisplatin (CIS), an effect which is known to occur through an interaction of curcumin and cisplatin at the level of the thiolic groups.…”

“…Vyas et al [61] conjugated curcumin with a recombinant chimeric antibody cPiPP (58), exhibiting high affinity and specificity for human chorionic gona-dotropin-(hCG-)/hCG, which was tested for growth inhibitory properties against MOLT-4 and U-937 cells. Interestingly, the antibody did not impair the growth of MOLT-4 and U-937 cells while its conjugate was lethal to both cell lines.…”

“…Similarly data on their in vivo activities in most cases is lacking. [64] have investigated the role of carbonyl and hydroxyl groups of Curcumin in PKC binding by synthesizing pyrazole (61)(62) and isoxazole (63-65) derivatives and studying their interaction with protein kinase-C (PKC-), especially with the activator-binding second cysteine-rich C1B sub-domain. All synthesized derivatives showed higher binding with the PKC--C1B compared with PKC--C1B and PKC--C1B.…”

Immunological Approaches Against Human Chorionic Gonadotropin for Control of Fertility and Therapy of Advanced‐Stage Cancers Expressing hCG/Subunits

“…The killing was confirmed by both trypan blue exclusion and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. 52 Therapeutic effect of Anti-hCG subunit antibodies on human cancer cells expressing hCG subunits Many years ago, our colleagues at Harvard Medical School brought to our notice human lung cancer (Chago) cells that expressed ectopically either hCG-a or hCG-b subunits. Antibodies directed at these subunits inhibited the multiplication of these cells in vitro.…”