Zenuo Biotech 
DOI: 10.1016/j.ejmech.2013.04.027
Source and publish data:
European Journal of Medicinal Chemistry p. 442 - 447 (2013)
ｕｐｄａｔｅ date:2022-08-16
Testosterone acetateCAS:1045-69-8
Article abstract of DOI:10.1016/j.ejmech.2013.04.027
The synthesis of 7α-testosterone-chlorambucil hybrid is reported. This compound is made from testosterone in a 6 step reaction sequence and with 23% overall yield. An alternative convergent reaction sequence yielded the same hybrid through a Grubbs metathesis reaction between chlorambucil allyl ester and 7α-allyltestosterone with 35% overall yield. MTT assays showed that the hybrid is selective towards hormone-dependent prostate cancer cell line (LNCaP (AR+)) and shows similar activity than the parent drug, chlorambucil. Thus, the new hybrid shows promising potential for drug targeting of hormone-dependent prostate cancer through its capacity of delivering chlorambucil directly to the site of treatment. This could extend the use of chlorambucil to prostate cancer in the future.
higher in prostate cancer cells compared to normal cells [4]. Consequently, androgens are involved not only in prostate tumor- In Canada, prostate cancer is the most frequently diagnosed cancer in men accounting for 28% of all new cancer cases [1]. However, prostate cancer ranks third with 10% of all cancer deaths in men, after lung and colorectal cancers with 28% and 12% of all cancer deaths, respectively [1]. Nonetheless, it is a serious health problem, not only in Canada but worldwide [2]. The androgens, testosterone (T) and dihydrotestosterone (DHT) are implicated in the development and normal functions of pros- tate cells. They are also involved in male sexual organ growth and sexual function. Testosterone is the principal androgen in the blood while DHT is the most potent androgen in the cells [3]. In order to induce their biological effects, androgens have to bind to the androgen receptor (AR): the hormoneereceptor complex binds DNA and modulates gene expression [4]. Upon androgen stimula- tion, the proliferation of prostate cells is increased and a malignant tumour can develop [4]. In addition, the androgen receptor level is igenesis, but also in hormone-dependent cancer progression, sup- porting the use of androgen deprivation therapy in prostate cancer patients [5]. However, one limitation is that most tumours become resistant to this type of therapy and so, additional options of treatments are required to care for the patient. This letter reports on the development of such alternate treatment for prostate cancer. Chlorambucil is an alkylating agent of the nitrogen mustard group and is used as cytostatic drug in cancer therapy [6]. In general, alkylating agents are both mutagenic and genotoxic [7]. The alkylating agents form adducts with DNA. However, they also form adducts with RNA and protein which contribute to the overall cytotoxicity [7]. The main side effects of chlorambucil are bone marrow suppression, anaemia and weak immune system [8,9]. Recently, we reported a series of estradiolechlorambucil hy- brids as anticancer drugs for site-directed chemotherapy of breast cancer [10]. The new hybrids showed moderate to significant cytotoxic activity in hormone-dependent (MCF-7) and hormone- independent (MDA-MB-436 and MDA-MB-486) breast cancer cell lines. Unfortunately, the hybrids were not selective towards the hormone-dependent breast cancer cell line MCF-7. Despite this, we sought to apply this type of strategy to the development of testosteroneechlorambucil hybrid for the treatment of prostate cancer. Therefore, this study was undertaken to verify if that
D. Bastien et al. / European Journal of Medicinal Chemistry 64 (2013) 442e447 443 particular combination could lead to a selective hybrid towards hormone-dependent prostate cancer in vitro. Scheme 2 illustrates an alternative synthesis of hybrid 1 by an olefin cross-metathesis reaction. Initially, derivative 3 was hydro- lyzed with 10% aqueous HCl in methanol under a light reflux to In order to increase the potential for selectivity towards the androgen receptor, the known 7 a-allyltestosterone was selected as yield 7a-allyltestosterone (6) with 95% yield. Secondly, chlor- the starting material. Position 7 is considered the site of choice as it is located midway between the two functional groups found on testosterone (ketone and hydroxyl) that interact with the AR. These functional groups should remain intact and free of steric hindrance to favour AR binding [11e13]. Furthermore, it was decided to link the testosterone moiety to chlorambucil via an ester bound. It was speculated that the ester linkage would be sufficiently stable to reach the target cells and would have the potential to be hydrolyzed within the acidic environment of the cancer, releasing the anti- cancer agent chlorambucil. If successful, this approach would broaden the use of chlorambucil to hormone-dependent prostate cancer. ambucil was transformed into 4-{4-[bis-(2-chloro-ethyl)-amino]- phenyl}-butyric acid allyl ester (7) upon treatment with oxalyl chloride followed by reaction with allyl alcohol and pyridine in dichloromethane with 95% yield. Derivatives 6 and 7 (excess) were treated with Hoveyda-Grubbs catalyst 2nd generation in DCM at reflux for 24 h. This reaction yielded the testosteroneechlorambucil hybrid (1) with 78% yield (cis:trans, 15:85). It is noteworthy, that the same reaction provided the dimer 8 (as a side product which was easily isolated by flash column chromatography). The latter is also an anticancer tetraalkylating agent. Of note, the dimer 8 could be easily hydrolyzed to chlorambucil which could be recycled to the allyl ester 7 and coupled to 7a-allyltestosterone 6 in order to avoid The current manuscript describes the synthesis of 7 a-testos- the loss of starting material. Derivative 8 was also synthesized by self condensation of 7 upon treatment with Hoveyda-Grubbs catalyst 2nd generation in DCM at reflux for 15 h with 75% yield. All compounds were fully characterized by the use of infrared (IR), nuclear magnetic resonance spectroscopy (NMR) and their respective high resolution mass analysis. teroneechlorambucil hybrid (1) (Fig. 1) using two synthetic methods. The steroid and the nitrogen-mustard alkylating parts are linked together by a trans-but-2-enyl tether chain. The manuscript also presents preliminary biological evaluation of the novel hybrid on two prostate cancer cell lines; LNCaP (androgen receptor posi- þꢀtive; AR ) and PC3 (androgen receptor negative; AR ).