LIPOSOMAL DAUNORUBICIN OVERCOMES DRUG RESISTANCE IN HUMAN BREAST,OVARIAN AND LUNG CARCINOMA CELLS

ABSTRACT

Multi-drug resistance due in part to membrane pumps such as P-glycoprotein (Pgp) is a major clinical problem in human cancers. We tested the ability of liposomally-encapsulated daunorubicin (DR) to overcome resistance to this drug. A widely used breast carcinoma cell line originally selected for resistance in doxorubicin (MCF7ADR) was 4-fold resistant to DR compared to the parent MCF7 cells (IC₅₀ 79 nM vs. 20 nM). Ovarian carcinoma cells (SKOV3) were made resistant by retroviral transduction of MDR1 cDNA and selection in vinblastine. The resulting SKOV3MGP1 cells were 130-fold resistant to DR compared to parent cells (IC₅₀ 5700 nM vs. 44 nM). Small-cell lung carcinoma cells (H69VP) originally selected for resistance to etoposide were 6-fold resistant to DR compared to H69 parent cells (IC₅₀ 180 nM vs. 30 nM). In all three cases, encapsulation of DR in liposomes as Daunoxome (Gilead) did not change the IC₅₀ of parent cells relative to free DR. However, liposomal DR overcame resistance in MCF7ADR breast carcinoma cells (IC₅₀ 20 nM), SKOV3MGP1 ovarian carcinoma cells (IC₅₀ 237 nM) and H69VP small-cell lung carcinoma cells (IC₅₀ 27 nM). Empty liposomes did not affect the IC₅₀ for free DR in the three resistant cell lines, nor did empty liposomes affect the IC₅₀ for other drugs that are part of the multi-drug resistance phenotype (etoposide, vincristine) in lung carcinoma cells. These data indicate the possible value of liposomal DR in overcoming Pgp-mediated drug resistance in human cancer.     

Biological Activities of Triterpenoids and Phenolic Compounds from Myrica cerifera Bark

Seven triterpenoids, 1  –  7 , two diarylheptanoids, 8 and 9 , four phenolic compounds, 10  –  13 , and three other compounds, 14  –  16 , were isolated from the hexane and MeOH extracts of the bark of Myrica cerifera L. (Myricaceae). Among these compounds, betulin ( 1 ), ursolic acid ( 3 ), and myricanol ( 8 ) exhibited cytotoxic activities against HL60 (leukemia), A549 (lung), and SK‐BR‐3 (breast) human cancer cell lines (IC₅₀ 3.1 – 24.2 μm ). Compound 8 induced apoptotic cell death in HL60 cells (IC₅₀ 5.3 μm ) upon evaluation of the apoptosis‐inducing activity by flow cytometric analysis and by Hoechst 33342 staining method. Western blot analysis on HL60 cells revealed that 8 activated caspases‐3, ‐8, and ‐9 suggesting that 8 induced apoptosis via both mitochondrial and death receptor pathways in HL60. Upon evaluation of the melanogenesis‐inhibitory activity in B16 melanoma cells induced with α‐melanocyte‐stimulating hormone (α‐MSH), erythrodiol ( 7 ), 4‐hydroxy‐2‐methoxyphenyl β‐d ‐glucopyranoside ( 13 ), and butyl quinate ( 15 ) exhibited inhibitory effects (65.4 – 86.0% melanin content) with no, or almost no, toxicity to the cells (85.9 – 107.4% cell viability) at 100 μm concentration. In addition, 8 , myricanone ( 9 ), myricitrin ( 10 ), protocatechuic acid ( 11 ), and gallic acid ( 12 ) revealed potent DPPH radical‐scavenging activities (IC₅₀ 6.9 – 20.5 μm ).     

Vibsane‐Type Diterpenoids from Viburnum odoratissimum and Their Cytotoxic and HSP90 Inhibitory Activities

Four new vibsane‐type diterpenoids, vibsanol I ( 1 ), 15‐hydroperoxyvibsanol A ( 2 ), 14‐hydroperoxyvibsanol B ( 3 ), 15‐O‐methylvibsanin U ( 4 ), and a new natural product, 5,6‐dihydrovibsanin B ( 5 ), as well as six known analogues, were isolated from the twigs and leaves of Viburnum odoratissimum. Their structures were elucidated by spectroscopic analyses and chemical derivatization method. All compounds showed different levels of cytotoxicity against five cell lines (HL‐60, A‐549, SMMC‐7721, MCF‐7, and SW480). Remarkably, 14,18‐O‐diacetyl‐15‐O‐methylvibsanin U ( 4a ) showed significant cytotoxicity against HL‐60, A‐549, SMMC‐7721, MCF‐7, and SW480, with IC₅₀ values of 0.15 ± 0.01, 0.69 ± 0.01, 0.41 ± 0.02, 0.75 ± 0.03, and 0.48 ± 0.03 μm , respectively. In addition, vibsanin K ( 10 ) was identified as a HSP90 inhibitor with an IC₅₀ value of 19.16 μm .     

Synthesis of 3‐Methylidene‐1‐tosyl‐2,3‐dihydroquinolin‐4(1H)‐ones as Potent Cytotoxic Agents

An efficient synthetic strategy to 3‐methylidene‐2,3‐dihydroquinolin‐4(1H)‐ones variously substituted in position 2 has been developed. The title compounds were synthesized in the reaction sequence involving reaction of diethyl methylphosphonate with methyl 2‐(tosylamino)benzoate, condensation of thus formed diethyl 2‐oxo‐2‐(2‐N‐tosylphenyl)ethylphosphonate with various aldehydes followed by successful application of the obtained 3‐(diethoxyphosphoryl)‐1,2‐dihydroquinolin‐4‐ols as Horner–Wadsworth–Emmons reagents for the olefination of formaldehyde. Also, enantioselective approach to the target compounds has been evaluated using 3‐dimenthoxyphosphoryl group as a chiral auxiliary. Single X‐ray crystal analysis of (2S)‐3‐(dimenthoxyphosphoryl)‐2‐phenyl‐1‐tosyldihydroquinolin‐4‐ol revealed the presence of strong resonance‐assisted hydrogen bond (RAHB). The obtained 3‐methylidene‐2,3‐dihydroquinolin‐4(1H)‐ones were then tested for their cytotoxic activity against two leukemia cell lines NALM‐6 and HL‐60 and a breast cancer MCF‐7 cell line. All compounds showed very high cytotoxic activity with the IC₅₀ values mostly below 1 μm in all three cancer cell lines. The selected analogs were also tested on human umbilical vein endothelial cells (HUVEC) and on human mammary gland/breast cells (MCF‐10A) to evaluate their influence on normal cells. Since one of the most serious problems in cancer chemotherapy is the development of drug resistance, the mRNA levels and activity of ABCB1 transporter considered to be the most important factor engaged in drug resistance, were evaluated in MCF‐7 cells treated with two selected analogs. Both compounds were strong ABCB1 transporter inhibitors that could prevent efflux of anticancer drugs from cancer cells.     

Cytotoxic and Melanogenesis‐Inhibitory Activities of Limonoids from the Leaves of Azadirachta indica (Neem)

Seventeen limonoids (tetranortriterpenoids), 1 – 17 , including three new compounds, i.e., 17‐defurano‐17‐(2,5‐dihydro‐2‐oxofuran‐3‐yl)‐28‐deoxonimbolide ( 14 ), 17‐defurano‐17‐(2ξ‐2,5‐dihydro‐2‐hydroxy‐5‐oxofuran‐3‐yl)‐28‐deoxonimbolide ( 15 ), and 17‐defurano‐17‐(5ξ‐2,5‐dihydro‐5‐hydroxy‐2‐oxofuran‐3‐yl)‐2′,3′‐dehydrosalannol ( 17 ), were isolated from an EtOH extract of the leaf of neem (Azadirachta indica). The structures of the new compounds were elucidated on the basis of extensive spectroscopic analyses and comparison with literature. Upon evaluation of the cytotoxic activities of these compounds against leukemia (HL60), lung (A549), stomach (AZ521), and breast (SK‐BR‐3) cancer cell lines, seven compounds, i.e., 1 – 3, 12, 13, 15 , and 16 , exhibited potent cytotoxicities with IC₅₀ values in the range of 0.1–9.9 μM against one or more cell lines. Among these compounds, cytotoxicity of nimonol ( 1 ; IC₅₀ 2.8 μM ) against HL60 cells was demonstrated to be mainly due to the induction of apoptosis by flow cytometry. Western blot analysis suggested that compound 1 induced apoptosis via both the mitochondrial and death receptor‐mediated pathways in HL60 cells. In addition, when compounds 1 – 17 were evaluated for their inhibitory activities against melanogenesis in B16 melanoma cells, induced with α‐melanocyte‐stimulating hormone (α‐MSH), seven compounds, 1, 2, 4 – 6, 15 , and 16 , exhibited inhibitory activities with 31–94% reduction of melanin content at 10 μM concentration with no or low toxicity to the cells (82–112% of cell viability at 10 μM ). All 17 compounds were further evaluated for their inhibitory effects against the Epstein? Barr virus early antigen (EBV‐EA) activation induced by 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) in Raji cells.     

Synthesis of New Pyrrolo[1,2-a]quinoxaline Derivatives as Potential Inhibitors of Akt Kinase

Akt kinases are attractive targets for small molecule drug discovery because of their key role in tumor cell survival/proliferation and their overexpression/activation in many human cancers. Recent efforts in the development and biological evaluation of small molecule inhibitors of Akt have led to the identification of novel Akt kinase inhibitors, based on a quinoxaline or pyrazinone scaffold. A series of new substituted pyrrolo[1,2-a]quinoxaline derivatives, structural analogues of these active quinoxaline or pyrazinone pharmacophores, was synthesized from various substituted 2-nitroanilines or 1,2-phenylenediamine via multistep heterocyclization process. These new compounds were tested for their in vitro ability to inhibit the proliferation of the human leukemic cell lines K562, U937 and HL60, and the breast cancer cell line MCF7. Three of these human cell lines (K562, U937 and MCF7) exhibited an active phosphorylated Akt form. The most promising active pyrroloquinoxalines were found to be 1a that inhibited K562 cell line proliferation with an IC₅₀ of 4.5 μM, and 1h that inhibited U937 and MCF7 cell lines with IC₅₀ of 5 and 8 μM, respectively. These two candidates exhibited more potent activities than the reference inhibitor A6730.     

In vitro effects of an in silico-modelled 17β-estradiol derivative in combination with dichloroacetic acid on MCF-7 and MCF-12A cells

Objectives: To investigate anti‐proliferative properties of a novel in silico‐modelled 17β‐oestradiol derivative (C9), in combination with dichloroacetic acid (DCA), on MCF‐7 and MCF‐12A cells. Materials and methods: xCELLigence system was employed to determine optimal seeding number for cells, and crystal violet assay was used to assess cell number and to determine IC₅₀ value (24 h) for combination treatment. Light and fluorescent microscopy techniques were used to morphologically detect types of cell death. Flow cytometry was used to analyse cell cycle and apoptosis. Results: Optimal seeding number for 96‐well plates was determined to be 5000–10 000 cells/well for both MCF‐7 and MCF‐12A cells. IC₅₀ for MCF‐7 cells of the combination treatment after 24 h was 130 nm of C9 in conjunction with 7.5 mm of DCA (P < 0.05). In contrast, the same concentration inhibited cell population growth by only 29.3% for MCF‐12As after 24‐h treatment (P < 0.05). Morphological studies revealed lower cell density of both types of combination‐treated cells. Flow cytometric analyses demonstrated increase in sub‐G₁ phase in combination‐treated MCF‐7 cells. Conclusions: These results demonstrate that the novel 17β‐oestradiol derivative C9, in combination with DCA is a potent anti‐proliferation treatment, with properties of selectivity towards tumourigenic cells. Thus, this warrants further studies as a potential combination chemotherapeutic agent for further cancer cell lines.     

Synthesis of Lanostane‐Type Triterpenoid N‐Glycosides and Their Cytotoxicity against Human Cancer Cell Lines

Seventeen lanostane‐type triterpenoid derivatives ( 2 – 18 ), including 11N‐glycosides ( 8 – 18 ), were synthesized from the natural triterpenoid, lanosterol ( 1 ), and were evaluated for their cytotoxicity against the human cancer cell lines, HL‐60, A549, and MKN45, as well as the normal human lung cells, WI‐38. Among them, N‐β‐d ‐2‐acetamido‐2‐deoxyglucoside ( 10 ) showed cytotoxicity against HL‐60, A549, MKN45, and WI‐38 cells (IC₅₀ 0.0078 – 2.8 μm ). However, N‐β‐d ‐galactoside ( 12 ) showed cytotoxicity against HL‐60 and MKN45 cells (IC₅₀ 0.0021 – 4.0 μm ), but not the normal WI‐38 cells. Furthermore, Western blot analysis suggested that 12 induces apoptosis by activation of caspases‐3, 8, and 9. These results will be useful for the synthesis of other tetracyclic triterpenoids or steroid N‐glycosides to increase their cytotoxicity and apoptosis‐inducing activities.     

Cytotoxic and Nitric Oxide Production‐Inhibitory Activities of Limonoids and Other Compounds from the Leaves and Bark of Melia azedarach

Nine limonoids, 1 – 9 , one apocarotenoid, 11 , one alkaloid, 12 , and one steroid, 13 , from the leaf extract; and one triterpenoid, 10 , five steroids, 14 – 18 , and two flavonoids, 19 and 20 , from the bark extract of Melia azedarach L. (Chinaberry tree; Meliaceae) were isolated. Among these compounds, three compounds, 4 – 6 , were new, and their structures were established as 3‐deacetyl‐28‐oxosalannolactone, 3‐deacetyl‐28‐oxosalanninolide, and 3‐deacetyl‐17‐defurano‐17,28‐dioxosalannin, respectively, on the basis of extensive spectroscopic analyses and comparison with literature data. All of the isolated compounds were evaluated for their cytotoxic activities against leukemia (HL60), lung (A549), stomach (AZ521), and breast (SK‐BR‐3) cancer cell lines. 3‐Deacetyl‐4′‐demethyl‐28‐oxosalannin ( 3 ) against HL60 and AZ521 cells, and methyl kulonate ( 10 ) against HL60 cells exhibited potent cytotoxicities with IC₅₀ values in the range of 2.8–5.8 μM . In addition, upon evaluation of compounds 1 – 13 against production of nitric oxide (NO) in mouse macrophage RAW 264.7 cells induced by lipopolysaccharide (LPS), seven, i.e., trichilinin B ( 1 ), 4 , ohchinin ( 7 ), 23‐hydroxyohchininolide ( 8 ), 21‐hydroxyisoohchininolide ( 9 ), 10 , and methyl indole 3‐carboxylate ( 12 ), inhibited production of NO with IC₅₀ values in the range of 4.6–87.3 μM with no, or almost no, toxicity to the cells (IC₅₀ 93.2–100 μM ). Western blot analysis revealed that compound 7 reduced the expression levels of the inducible NO synthase (iNOS) and COX‐2 proteins in a concentration‐dependent manner. Furthermore, compounds 5, 6, 13 , and 18 – 20 exhibited potent inhibitory effects (IC₅₀ 299–381 molar ratio/32 pmol TPA) against Epstein? Barr virus early antigen (EBV‐EA) activation induced by 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) in Raji cell line.     

Salvisertin A,a New Hexacyclic Triterpenoid,and Other Bioactive Terpenes from Salvia deserta Root

Using various chromatographic methods, a new hexacyclic triterpenoid, 2β,3β,24β‐trihydroxy‐12,13‐cyclotaraxer‐l4‐en‐28oic acid ( 1 ), together with ten known compounds, 2α,3α,23‐trihydroxyurs‐12,20(30)‐dien‐28oic acid ( 2 ), 6,7‐dehydroroyleanone ( 3 ), horminone ( 4 ), 7‐O‐methylhorminone ( 5 ), sugiol ( 6 ), demethylcryptojaponol ( 7 ), 14‐deoxycoleon U ( 8 ), 5,6‐didehydro‐7‐hydroxy‐taxodone ( 9 ), ferruginol ( 10 ), and dichroanone ( 11 ), were isolated from the roots of Salvia deserta. Their structures were identified on the basis of spectroscopic analysis and comparison with the reported data. The individual compounds ( 1 , 3  –  8 ) were screened for cytotoxic activity, using the sulforhodamine B bioassay (SRB) method. As the results, Compounds 3 , 5 , and 8 showed cytotoxic potency against A549, MDA‐MB‐231, KB, KB‐VIN, and MCF7 cell lines with IC₅₀ values ranging from 6.5 to 10.2 μm .     

Synthesis and Anticancer Activity of 3‐(Substituted Aroyl)‐4‐(3,4,5‐trimethoxyphenyl)‐1H‐pyrrole Derivatives

A series of 3‐(substituted aroyl)‐4‐(3,4,5‐trimethoxyphenyl)‐1H‐pyrrole derivatives were synthesized and determined for their anticancer activity against eleven cancer cell lines and two normal tissue cell lines using MTT assay. Among the synthesized compounds, compound 3f was the most potent compound against A375, CT‐26, HeLa, MGC80‐3, NCI‐H460 and SGC‐7901 cells (IC₅₀ = 8.2 – 31.7 μm ); 3g , 3n and 3a were the most potent compounds against CHO (IC₅₀ = 8.2 μm ), HCT‐15 (IC₅₀ = 21 μm ) and MCF‐7 cells (IC₅₀ = 18.7 μm ), respectively. Importantly, all the target compounds showed no cytotoxicity towards the normal tissue cell (IC₅₀ > 100 μm ). Thus, these compounds with the potent anticancer activity and low toxicity have potential for the development of new anticancer chemotherapy agents.     

Cytotoxic Activities of Amino Acid‐Conjugate Derivatives of Abietane‐Type Diterpenoids against Human Cancer Cell Lines

Nine amino acid conjugate derivatives, each 2 – 10 and 12 – 20 , were prepared from abietic acid ( 1 ) and dehydroabietic acid ( 11 ), respectively, and they were evaluated for their cytotoxicities against four human cancer cell lines, i.e., leukemia (HL60), lung (A549), stomach (AZ521), and breast (SK‐BR‐3). All compounds showed cytotoxicities against HL60 with IC₅₀ values in the range of 2.3–37.3 μM . In addition, most of the derivatives exhibited moderate cytotoxicities against the other cancer cell lines. Among the derivatives, methyl N‐[18‐oxoabieta‐8,11,13‐trien‐18‐yl]‐L ‐tyrosinate ( 19 ) exhibited potent cytotoxic activities against four cancer cell lines with IC₅₀ values of 2.3 (HL60), 7.1 (A549), 3.9 (AZ521), and 8.1 μM (SK‐BR‐3). Furthermore, all derivatives were shown to possess high selective cytotoxic activities for leukemia cells, since they exhibited only weak cytotoxicities against normal lymphocyte cell line RPMI1788.     

First Syntheses of Melophlins P,Q, and R,and Effects of Melophlins on the Growth of Microorganisms and Tumor Cells

The marine tetramic acid (=1,5‐dihydro‐4‐hydroxy‐2H‐pyrrol‐2‐ones) derivatives melophlin P, Q, and R ( 1p – 1r , resp.) were synthesized for the first time in only four steps. Together with the congenerous melophlins A–C and G, they were also tested for antimicrobial and cytotoxic effects. Melophlins B, C, P, Q, and R, which share a 5‐Me residue, showed some antibacterial activity, mainly in Gram‐positive bacteria. Melophlins B, C, and R, which have Me‐branched 3‐acyl side chains in common, inhibited the growth of cells of human KB‐3‐1 cervix carcinoma, A‐498 kidney carcinoma, and U‐937 leukemia with IC₅₀ values <10 μM . They were similar in activity to cisplatin. Melophlin Q, also Me‐branched, was astoundingly specific in inhibiting A‐498 kidney cancer cells, while melophlin P inhibited U‐937 leukemia cells particularly well. The position of the Me branch is decisive for the magnitude of the antiproliferative effect of the melophlin couples B/C and R/Q.     

Cytotoxic and Apoptosis‐Inducing Activities,and Anti‐Tumor‐Promoting Effects of Cyanogenated and Oxygenated Triterpenes

Two of each semisynthetic lanostane‐ and cycloartane‐type triterpenes with a cyano‐enone functionality, i.e., 13 and 18 , and 23 and 28 , respectively, sixteen of their synthetic intermediates, 9 – 12, 14 – 17, 19 – 22 , and 24 – 27 , along with seven semisynthetic oxygenated triterpene acetates, 29 – 35 , and eight natural hydroxy triterpenes, 1 – 8 , were evaluated for their cytotoxic activities against leukemia (HL60), lung (A549), stomach (AZ521), and breast (SK‐BR‐3) cancer cell lines. One natural triterpene, 8 , and ten semisynthetic triterpenes, 9, 13, 15, 18, 23, 25, 28, 29, 32 , and 33 , exhibited potent cytotoxicities against one or more cell lines with IC₅₀ values in the range of 1.4–9.9 μM . Two lanostane‐type triterpenes with a cyano‐enone functionality, 3‐oxolanosta‐1,8,24‐triene‐2‐carbonitrile ( 13 ) and 3‐oxolanosta‐1,8‐diene‐2‐carbonitrile ( 18 ), induced apoptosis in HL60 cells, as observed by membrane phospholipid exposure in flow cytometry. Western blot analysis showed that 13 and 18 significantly reduced procaspases‐3, ‐8, and ‐9, and increased cleaved caspases‐3, ‐8, and ‐9. These findings indicated that compounds 13 and 18 induced apoptosis in HL60 cells via both the mitochondrial and the death receptor‐mediated pathways. In addition, upon evaluation of the inhibitory effects on Epstein? Barr virus early antigen (EBV‐EA) activation induced with 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) in Raji cells, seven natural triterpenes, 1 – 6 and 8 , and ten semisynthetic triterpenes, 9, 10, 14, 15, 19, 20, 24, 25, 29 , and 30 , exhibited inhibitory effects which were higher than that of β‐carotene, a vitamin A precursor studied widely in cancer‐chemoprevention animal models.     

Synergistic Combination of Gemcitabine and Dietary Molecule Induces Apoptosis in Pancreatic Cancer Cells and Down Regulates PKM2 Expression

Gemcitabine, an effective agent in treatment of cancer of pancreas, has undergone failures in many instances after multiple cycles of therapy due to emergence of drug resistance. Combination of dietary compounds with clinically validated drugs has emerged as an effective therapeutic approach to treat pancreatic tumors, refractory to gemcitabine therapy. In order to optimize a possible synergistic combination of Gemcitabine (GCB) with dietary molecules, Betuilnic acid (BA) and Thymoquinone (TQ), stand-alone IC₅₀ dose of GCB, BA and TQ was calculated for pancreatic cancer cell lines. Fixed IC₅₀ dose ratio of the dietary molecules in combination with reduced IC₅₀ dose of GCB was tested on GCB resistant PANC-1 and sensitive MIA PaCa-2 cells for synergism, additive response and antagonism, using calcusyn. Combination index (CI) revealed that pre-treatment of BA and TQ along with GCB synergistically inhibited the cancer cell proliferation in in-vitro experiments. Pyruvate kinase (PK) M2 isoform, a promising target involved in cancer cell metabolism, showed down-regulation in presence of TQ or BA in combination with GCB. GCB with BA acted preferentially on tumor mitochondria and triggered mitochondrial permeability transition. Pre-exposure of the cell lines, MIA PaCa-2 and PANC-1, to TQ in combination with GCB induced apoptosis. Thus, the effectiveness of BA or TQ in combination with GCB to inhibit cell proliferation, induce apoptosis and down-regulate the expression of PKM2, reflects promise in pancreatic cancer treatment.     

Selective cytotoxicity and modulation of apoptotic signature of breast cancer cells by Pithecellobium dulce leaf extracts

We report the potent and selective cytotoxicity of the crude aqueous leaf extract from the medicinal plant, Pithecellobium dulce toward the human breast cancer cells (MCF‐7), but not the normal cells (MCF‐10A). The cytotoxicity was found to be dose and time dependent, as 300 µg/mL of the extract decreased the cell viability to 50% (IC₅₀) in 48 h. The induction of apoptosis in the breast cancer cells after treatment was confirmed by significant percentage (24.7%), of early apoptotic cells (AnnexinV ⁺Propidium Iodide^_) in treated cells as compared to control cells (3.5%). We observed a significant upregulation in the mRNA expression of various pro‐apoptotic gene such as Bax (21.1 folds), p21(14.4 folds), p53 (11.7 folds), TNF (10.2 folds) and fas (6.3 folds) after treatment as compared to untreated cells. On the other hand, the relative mRNA expression of anti‐apoptotic genes such as Bcl‐2, NF‐KB and Cdk was reduced. The selective upregulation of pro‐apoptotic gene and down regulation of specific anti‐apoptotic genes could be the inducing factor for apoptotic cell death in MCF‐7 cells after treatment with the herbal extract. We believe that our findings provide a foundation for further studies on this formulation as a potential therapeutic candidate for breast cancer. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:756–766, 2016     

Synthesis and biological evaluation of ethacrynic acid derivatives bearing sulfonamides as potent anti-cancer agents

A series of ethacrynic acid (2-[2,3-dichloro-4-(2-methylidenebutanoyl)phenoxy]acetic acid) (EA, Edecrin) containing sulfonamides linked via three types of linkers namely 1,2-ethylenediamine, piperazine and 4-aminopiperidine was synthesized and subsequently evaluated in vitro against HL60 and HCT116 cancer cell lines. All the EA analogs, excluding 6a and 6c, showed anti-proliferative activity with IC_50s in the micromolar range (less than 4 uM). Three derivatives 6b, 7b and 7e were selected for their interesting dual activity on HL60 cell line in order to be further evaluated against a panel of cancer cell lines (HCT116, A549, MCF7, PC3, U87-MG and SKOV3) as well as on MRC5 as a normal cell line. These compounds displayed IC₅₀ values in nanomolar range against A549, MCF7, PC3 and HCT116 cell lines, deducing the discovery that piperazine or 4-aminopiperidine is the linker’s best choice to develop EA analogs with highly potent anti-proliferative activities own up to 24 nM. Besides, in terms of selectivity, those linkers are more suitable offering safety ratios of up to 63.8.     

Study of Antimalarial Activity of Chemical Constituents from Diospyros quaesita

Bioassay‐directed fractionation led to the isolation of seven compounds from a sample of the dried leaves, twigs, and branches of Diospyros quaesita Thw . (Ebenaceae). One of the isolates, betulinic acid 3‐caffeate ( 1 ), showed in vitro antimalarial activity against Plasmodium falciparum clones D₆ (chloroquine‐sensitive) and W₂ (chloroquine‐resistant) with IC₅₀ values of 1.40 and 0.98 μM , respectively. Evaluation of compound 1 in the human oral epidermoid (KB) cancer cell line revealed cytotoxicity at ED₅₀ of 4.0 μM . In an attempt to reduce the cytotoxicity of 1 , the acetylated derivative 1a and betulinic acid ( 1b ) were prepared. Of the seven isolates, diospyrosin ( 2 ) was determined to be a new neolignan. In addition to 1 , other known compounds isolated in this study were pinoresinol, lariciresinol, N‐benzoyl‐L ‐phenylalaninol, scopoletin, and poriferast‐5‐en‐3β,7α‐diol. The structure of 2 was elucidated based on spectroscopic data analysis including 1D‐ and 2D‐NMR, and HR‐ESI‐MS.     

Pyranochromones from Dictyoloma vandellianum A. Juss and Their Cytotoxic Evaluation

One new chromone 3,3‐dimethylallylspatheliachromene methyl ether ( 1 ), as well as five known chromones, 6‐(3‐methylbut‐2‐enyl) allopteroxylin methyl ether ( 2 ), 6‐(3‐methylbut‐2‐enyl) allopteroxylin ( 3 ), 3,3‐dimethylallylspatheliachromene ( 4 ), 5‐O‐methylcneorumchromone K ( 5 ) and spatheliabischromene ( 6 ), two alkaloids, 8‐methoxy‐N‐methylflindersine ( 7 ) and 8‐methoxyflindersine ( 8 ), and two limonoids, limonin diosphenol ( 9 ) and rutaevin ( 10 ), were isolated from Dictyoloma vandellianum A. Juss (Rutaceae). Cytotoxic activities towards tumor cell lines B16‐F10, HepG2, K562 and HL60 and non‐tumor cells PBMC were evaluated for compounds 1  –  6 . Compound 1 was the most active showing IC₅₀ values ranging from 6.26 to 14.82 μg/ml in B16‐F10 and K562 cell lines, respectively, and presented IC₅₀ value of 11.65 μg/ml in PBMC cell line.