الفهرس 
IntroductionOnly 14 pages are availabe for public view
Abstract
Cancer is a disease in which a group of abnormal cells grow uncontrollably by disregarding the normal rules of cell division. Normal cells are constantly subjects to signals that dictate weather the cell should divide and differentiate to another cell or die. Apoptosis is a normal physiological process which is very crucial to maintain tissue homeostasis. Dysregulated apoptosis can lead to various diseases as cancer. Thus, evasion of apoptosis stands out as a key hallmark of cancer cells. BCL-2 family of proteins is the key modulator of the mitochondrial apoptotic pathway. Therefore, the balance between the anti-apoptotic (BCL-2, BCL-XL and MCL-1) and pro-apoptotic (BAK, BAX, BAD, PUMA and NOXA) members of this family will govern cell fate. Overexpression of anti-apoptotic BCL-2 members is implicated in the progression of many human cancers as well as the emerging resistance to various anti-cancer agents including targeted therapies. Indeed, inhibition of the anti-apoptotic BCL-2 members by small molecule BH3 mimetics may provide an excellent approach in cancer therapy.
Herein, our research objective is to design, synthesize and biologically evaluate novel inhibitors targeting BCL-2 with a promising anti-cancer activity. The design process aimed to target BCL-2 BH3 binding groove and started by identification of the key interactions between BCL-2 binding groove and a previously reported BCL-2 inhibitors following, rational modification of the lead compound was proposed and a series of novel benzothiazole-based derivatives were suggested and finally molecular modeling studies including field alignment and docking were performed to investigate the predicted binding modes and binding affinities of the designed compounds.
The designed compounds were synthesized, purified and structurally confirmed by different analytical and spectral techniques.
The study involved the synthesis of the following reported intermediates:
1) Ethyl 4-fluoro-3-nitrobenzoate (I).
2) 1-((3-Fluorobenzyl)oxy)-4-nitrobenzene (IVa).
3) 1-((3-Chlorobenzyl)oxy)-4-nitrobenzene (IVb).
4) 1-((4-Chlorobenzyl)oxy)-4-nitrobenzene (IVc).
5) 1-((4-Bromobenzyl)oxy)-4-nitrobenzene (IVd).
6) 1-((4-Methylbenzyl)oxy)-4-nitrobenzene (IVe).
7) 4-((3-Fluorobenzyl)oxy) aniline (Va).
8) 4-((3-Chlorobenzyl)oxy) aniline (Vb).
9) 4-((4-Chlorobenzyl)oxy) aniline (Vc).
10) 4-((4-Bromobenzyl)oxy)aniline (Vd).
11) 4-((4-Methylbenzyl)oxy)aniline (Ve).
12) 4-Nitro-1-(4-bromophenoxy)benzene (VIa).
13) 4-Nitro-1-(3-fluoro-4-chlorophenoxy)benzene (VIb).
14) 4-(4-Bromophenoxy)aniline (VIIa).
15) 4-(3-Fluoro-4-chloro phenoxy) aniline (VIIa).
16) Ethyl 2-aminobenzo[d]thiazole-6-carboxylate (VIII).
17) 6-Nitrobenzo[d]thiazol-2-amine (XIX).
18) N-(6-Nitrobenzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XX).
19) N-(6-Aminobenzo[d]thiazol-2-yl) naphthalene-2-sulfonamide (XXI).
Also, it comprised the synthesis of the following new intermediates:
1) Ethyl 3-nitro-4-(phenethylamino)benzoate (II).
2) 3-Nitro-4-(phenethylamino)benzoic acid (III).
3) 1-((4-Trifluoromethylbenzyl)oxy)-4-nitrobenzene (IVf).
4) 4-((4-Triflouromethylbenzyl)oxy)aniline (Vf).
5) Ethyl 2-(naphthalene-2-sulfonamido)benzo[d]thiazole-6-carboxylate (IX).
6) 2-(Naphthalene-2-sulfonamido)benzo[d]thiazole-6-carboxylic acid (X).
7) Ethyl 2-(3-nitro-4-(phenethylamino) benzamido)benzo[d]thiazole-6-carboxylate (XIV).
8) 2-(3-Nitro-4-(phenethylamino)benzamido)benzo[d]thiazole-6-carboxylic acid (XV).
Furthermore, the study involved the synthesis and characterization of the following new final compounds:
1) N-(6-(4-Phenylpiperazine-1-carbonyl)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XIa).
2) N-(6-(4-(2-Fluorophenyl)piperazine-1-carbonyl)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XIb).
3) N-(6-(4-(2-Methoxyphenyl)piperazine-1-carbonyl)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XIc).
4) N-(6-(4-(4-Chlorophenyl)piperazine-1-carbonyl)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XId).
5) N-(6-(4-(3,4-Dichlorophenyl)piperazine-1-carbonyl)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XIe).
6) N-(6-(4-Benzhydrylpiperazine-1-carbonyl)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XIf).
7) (E)-N-(6-(4-Cinnamylpiperazine-1-carbonyl)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide( XIg).
8) N-(6-(4-(Tetrahydrofuran-2-carbonyl)piperazine-1-carbonyl)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XIh).
9) N-(6-(4-(Benzo[d]dioxol-5-ylmethyl)piperazine-1-carbonyl)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XIi).
10) N-(4-((3-Fluorobenzyl)oxy)phenyl)-2-(naphthalene-2-sulfonamido)benzo[d] thiazole-6-carboxamide (XIIa).
11) N-(4-((3-Chlorobenzyl)oxy)phenyl)-2-(naphthalene-2-sulfonamido)benzo[d] thiazole-6-carboxamide (XIIb).
12) N-(4-((4-Chlorobenzyl)oxy)phenyl)-2-(naphthalene-2-sulfonamido)benzo[d] thiazole-6-carboxamide (XIIc).
13) N-(4-((4-Bromobenzyl)oxy)phenyl)-2-(naphthalene-2-sulfonamido)benzo[d] thiazole-6-carboxamide (XIId).
14) N-(4-((4-Methylbenzyl)oxy)phenyl)-2-(naphthalene-2-sulfonamido)benzo[d] thiazole-6-carboxamide (XIIe).
15) N-(4-((4-Trifluormethylbenzyl)oxy)phenyl)-2-(naphthalene-2-sulfonamido)benzo [d]thiazole-6-carboxamide )XIIf).
16) N-(4-(4-Chloro-3-fluorophenoxy)phenyl)-2-(naphthalene-2-sulfonamido) benzo[d]thiazole-6-carboxamide (XIIIa).
17) N-(4-(4-Bromophenoxy)phenyl)-2-(naphthalene-2-sulfonamido)benzo[d] thiazole-6-carboxamide (XIIIb).
18) N-(6-(4-(2-Methoxyphenyl) piperazine-1-carbonyl) benzo [d] thiazol-2-yl)-3-nitro-4-(phenethylamino)benzamide (XVIa).
19) N-(6-(4-(3,4-Dichlorophenyl)piperazine-1-carbonyl)benzo[d]thiazol-2-yl)-3-nitro-4-(phenethylamino)benzamide (XVIb).
20) N-(6-(4-Benzhydrylpiperazine-1-carbonyl)benzo[d]thiazol-2-yl)-3-nitro-(phenethylamino)benzamide (XVIc).
21) (E)-N-(6-(4-Cinnamylpiperazine-1-carbonyl)benzo[d]thiazol-2-yl)-3-nitro-4-(phenethylamino)benzamide (XVId).
22) 3-Nitro-4-(phenethylamino)-N-(6-(4-(tetrahydrofuran-2-carbonyl)piperazine-1-carbonyl)benzo[d]thiazol-2-yl)benzamide (XVIe).
23) N-(4-((3-Chlorobenzyl)oxy)phenyl)-2-(3-nitro-4-(phenethylamino)benzamido) benzo[d]thiazole-6-carboxamide (XVIIa).
24) N-(4-((4-Bromobenzyl)oxy)phenyl)-2-(3-nitro-4-(phenethylamino)benzamido) benzo[d]thiazole-6-carboxamide (XVIIb).
25) N-(4-((4-Methylbenzyl)oxy)phenyl)-2-(3-nitro-4-(phenethylamino)benzamido) benzo[d]thiazole-6-carboxamide (XVIIc).
26) N-(4-((4-Trifluoromethylbenzyl)oxy)phenyl)-2-(3-nitro-4- (phenethylamino)benzamido)benzo[d]thiazole-6-carboxamide (XVIId).
27) N-(4-(4-Chloro-3-fluorophenoxy)phenyl)-2-(3-nitro-4-(phenethylamino)benzamido)benzo[d]thiazole-6-carboxamide (XVIIIa).
28) N-(4-(4-Bromophenoxy)phenyl)-2-(3-nitro-4-(phenethylamino)benzamido benzo[d]thiazole-6-carboxamide (XVIIIb).
29) N-(6-(3-Phenylureido)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XXIIa).
30) N-(6-(3-(3-Chlorophenyl)ureido)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XXIIb).
31) N-(6-(3-(3-Bromophenyl)ureido)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XXIIc).
32) N-(6-(3-(3-Methoxyphenyl)ureido)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XXIId).
33) N-(6-(3-(m-tolyl)ureido)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XXIIe).
34) N-(6-(3-(4-Bromophenyl)ureido)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XXIIf).
35) N-(6-(3-(4-Chloro-3-(trifluoromethyl)phenyl)ureido)benzo[d]thiazol-2-yl) naphthalene-2-sulfonamide (XXIIg).
36) N-(6-(3-(3,4-Dichlorophenyl)ureido)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XXIIh).
37) N-(6-(3-(4-Chloro-2-methylphenyl)ureido)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XXIIi) .
38) N-(6-(3-(3-Chloro-4-methylphenyl)ureido)benzo[d]thiazol-2-yl)naphthalene-2-sulfonamide (XXIIj).
In vitro biological evaluation was accomplished through testing both anti- proliferative activity and BCL-2 inhibitory activity for all of the newly synthesized compounds. Some of the tested compounds have demonstrated a moderate to good BCL-2 inhibitory activity. Promising candidates, which exhibited BCL-2 inhibition percent above 60% at 10 µM concentration (XIId, XVIIb-d & XXIIf) were further investigated for their dose-related BCL-2 inhibitory activity at 5 different concentrations to calculate their IC50 values. Compounds (XVIIc and XVIId) showed the highest potent micromolar BCL-2 inhibition (IC50 of 0.471 µM and 0.363 µM, respectively). Additionally, in vitro anti-proliferative activity against NCI 60-cell line revealed that the highest cell growth inhibition was demonstrated by compound (XVId) with mean growth percent of 48.23%. It exhibited broad spectrum and good anti-proliferative activity against almost all cell lines.
Finally, thorough molecular docking, using C-DOCKER protocol in Discovery Studio 2.5 software was attempted to investigate the binding mode of the targeted compounds and interpret their variable inhibitory activity.