In vitro cytotoxic potential of Polyalthia longifolia on human cancer cell lines and induction of apoptosis through mitochondrial-dependent pathway in HL-60 cells

Polyalthia longifolia is a lofty evergreen tree found in India and Sri Lanka. We are reporting first time the anticancer potential of P. longifolia leaves extract (A001) and its chloroform fraction (F002). Both inhibited cell proliferation of various human cancer cell lines in which colon cancer cells SW-620 showed maximum inhibition with IC(50) value 6.1 microg/ml. Furthermore, F002 induce apoptosis in human leukemia HL-60 cells as measured by several biological end points. F002 induce apoptotic bodies formation, DNA ladder, enhanced annexin-V-FITC binding of the cells, increased sub-G(0) DNA fraction, loss of mitochondrial membrane potential (DeltaPsi(mt)), release of cytochrome c, activation of caspase-9, caspase-3, and cleavage of poly ADP ribose polymerase (PARP) in HL-60 cells. All the above parameters revealed that F002-induced apoptosis through the mitochondrial-dependent pathway in HL-60 cells.     

Arsenic trioxide-induced apoptosis through oxidative stress in cells of colon cancer cell lines

Exposure of three colon cancer cell lines, SW480, DLD-1, and COLO201, to arsenic trioxide in the medium induced a marked concentration-dependent suppression of cell growth. The intracellular contents of reduced glutathione (GSH) in these cell lines tended to be inversely correlated with the sensitivity of the cells to arsenic trioxide. Among the cell lines, SW480 cells underwent apoptosis at the low arsenic trioxide concentration of 2 microM, which was prevented by pretreatment of the cells with N-acetylcysteine and was enhanced by buthionine sulfoximine. The production of reactive oxygen intermediates which were examined by 2',7'-dichlorodihydrofluorescein diacetate (H2DCF-DA), increased with time after treatment with arsenic trioxide. The apoptosis was executed by the activation of caspase 3, which was shown by Western blot, enzymatic activity, and apoptosis inhibition assay. The mitochondrial membrane potential of adherent apoptotic SW480 cells and the cells from intermediate layer separated by density gradient centrifugation, both of which showed the active form of caspase 3 by Western blot analysis, was not lost. The overexpression of Bcl-2 protein in SW480 cells could not prevent the apoptosis induced by the treatment with arsenic trioxide. All these findings indicate that arsenic trioxide-induced apoptosis in SW480 cells is executed by the activation of caspase 3 without mediating by mitochondria under the overproduction of reactive oxygen species.     

bcl-2和bax及NF-kB在白藜芦醇诱导肝癌细胞凋亡中的作用

目的探讨白藜芦醇诱导肝癌细胞凋亡的途径。方法白藜芦醇体外处理HepG2肝癌细胞24h后,以免疫组化检测凋亡调控基因bc1-2和bax及NF-kB的表达。结果白藜芦醇处理组HepG2细胞bc1-2的阳性积分和NF-kB的阳性细胞密度均明显低于对照组(P<0.01);而bax阳性积分明显高于对照组(P<0.01)。结论白藜芦醇能下调HepG2细胞bc1-2基因的表达,上调bax的表达,同时抑制NF-kB的活化,这可能是其诱导HepG2细胞凋亡的途径之一。     

Bladder cancer cell viability inhibition and apoptosis induction by baicalein through targeting the expression of anti-apoptotic genes

The study was aimed to investigate the effect of baicalein, a flavonoid molecule isolated from the plant Oroxylum indicum on bladder cancer cell viability. The results revealed that baicalein treatment of T24 and 253J bladder cancer cells targeted the expression of mRNA and proteins corresponding to the anti-apoptotic genes. RT-PCR assay showed that anti-apoptotic genes were markedly over-expressed in the bladder cancer cells. Exposure of the bladder cancer cells to baicalein at 5 mg/mL doses for 72 h led to reduction in the expression of mRNA levels of antiapoptotic genes. In T24 cells, the levels of BCL2, Bcl-xL, XIAP and surviving was reduced by 65, 69, 58 and 72%, respectively. In T24 and 253J cells exposure to baicalein for 72 h resulted respectively in 39 and 46% reduction in cell viability. Baicalein treatment also induced apoptosis in the bladder cancer cells. In T24 and 253J cells baicalein treatment at 5 mg/mL for 72 h induced apoptosis in 79 and 86% cells respectively. Thus, baicalein mediated reduction in antiapoptotic gene expression inhibits viability and induces apoptosis in bladder cancer cells. Therefore, baicalein is of therapeutic importance for the development of bladder cancer treatment strategy.     

Mefenamic acid-induced apoptosis in human liver cancer cell-lines through caspase-3 pathway

Non-steroidal anti-inflammatory drugs (NSAIDs) have anti-proliferative effects and induce apoptosis in colon and other cancers. In the present study, we report that mefenamic acid (MEF), a member of NSAIDs, has an inhibitory effect on a proliferation of liver cancer cells. We used Chang and Huh-7 cells as human liver cancer cells. MEF-treated Huh-7 and Chang cells displayed apoptotic morphological changes and the portion of cells in sub G1 was increased 3-fold and 6-fold, respectively, at a 200 microM concentration. We also show an MEF-enhanced binding of annexin V to cells and an increased activity of caspase-3 to cleave PARP-1 and caspase itself. The inhibitor of caspase-3 blocked PARP-1 cleavage activity and protected against MEF-induced apoptotic cell death. These results indicate that MEF induces apoptosis in human liver cancer cells.     

Juglone,isolated from Juglans mandshurica Maxim,induces apoptosis via down-regulation of AR expression in human prostate cancer LNCaP cells

Juglone is a natural compound which has been isolated from Juglans mandshurica Maxim. Recent studies have shown that juglone had various pharmacological effects such as anti-viral, anti-bacterial and anti-cancer. However, its anti-cancer activity on human prostate cancer LNCaP cell has not been examined. Thus, the current study was designed to elucidate the molecular mechanism of apoptosis induced by juglone in androgen-sensitive prostate cancer LNCaP cells. MTT assay was performed to examine the anti-proliferative effect of juglone. Occurrence of apoptosis was detected by Hoechst 33342 staining and flow cytometry in LNCaP cells treated with juglone for 24 h. The result shown that juglone inhibited the growth of LNCaP cells in a dose-dependent manner. Morphological changes of apoptotic body formation after juglone treatment were observed by Hoechst 33342 staining. This apoptotic induction was associated with loss of mitochondrial membrane potential, and caspase-3, -9 activation. Moreover, we found that juglone significantly inhibited the expression levels of androgen receptor (AR) and prostate-specific antigen (PSA) in a dose-dependent manner, as well as abrogated up-regulation of AR and PSA genes with and/or without dihydrotestosterone (DHT). Take together, our results demonstrated that juglone might induce the apoptosis in LNCaP cell via down-regulation of AR expression. Therefore, our results indicated that juglone may be a potential candidate of drug for androgen-sensitive prostate cancer.     

lH-Pyrazolo[3,4-b]quinolin-3-amine derivatives inhibit growth of colon cancer cells via apoptosis and sub G1 cell cycle arrest

A series of lH-pyrazolo[3,4-b]quinolin-3-amine derivatives were synthesized and evaluated for anticancer efficacy in a panel of ten cancer cell lines, including breast (MDAMB-231 and MCF-7), colon (HCT-116, HCT-15, HT-29 and LOVO), prostate (DU-145 and PC3), brain (LN-229), ovarian (A2780), and human embryonic kidney (HEK293) cells, a non-cancerous cell line. Among the eight derivatives screened, compound QTZ05 had the most potent and selective antitumor efficacy in the four colon cancer cell lines, with IC₅₀ values ranging from 2.3 to 10.2?µM. Furthermore, QTZ05 inhibited colony formation in HCT-116 cells in a concentration-dependent manner. Cell cycle analysis data indicated that QTZ05 caused an arrest in the sub G1 cell cycle in HCT-116 cells. QTZ05 induced apoptosis in HCT-116 cells in a concentration-dependent manner that was characterized by chromatin condensation and increase in the fluorescence of fluorochrome-conjugated Annexin V. The findings from our study suggest that QTZ05 may be a valuable prototype for the development of chemotherapeutics targeting apoptotic pathways in colorectal cancer cells.     

Chemical constituents from Abrus cantoniensis and their cytotoxic effects on cancer cells

Two new compounds named 4-(4-hydroxybenzyl)-isofraxidin (1) and 1''-methoxyl-bavacoumestan B (2), along with five known compounds (3–7) were isolated from the EtOAc-soluble extract of Abrus cantoniensis. Their structures were elucidated with spectroscopic and physico-chemical analyses. All isolates were evaluated for their cytotoxic activities against four cancer cell lines including HepG2, SMMC-7721, A549 and MCF-7. Among them, compounds 1 and 5 exhibited significant cytotoxic activity on the above four cell lines. In particular, 1 showed the potent cytotoxic activity on HepG2 and SMMC-7721 cells with IC₅₀ values of 4.31 ± 0.5 and 3.24 ± 0.9 μM, respectively.     

Rapid induction of apoptosis in human gastric cancer cell lines by sorbitol

Most solid tumors, including gastric cancers, respond poorly to non-surgical treatments which are expected to induce an apoptosis-dependent involution. We hypothesize that the apoptotic machinery in solid tumors is either defective or in a suppressed condition. Overcoming the ineffective induction of apoptosis may improve the responsiveness of solid tumors to non-surgical treatments. Recently, sorbitol, a kind of hexose, has been found to be an effective inducer of apoptosis in HEp-2 cells. Therefore, it is of particular interest to examine the effect of sorbitol-treatment on gastric cancer cells. In the present study, we selected 4 gastric cancer cell lines which have been reported to exhibit different abilities in regard to apoptosis induction, and examined the effect of sorbitol-treatment on apoptosis induction. Within 3 hr after sorbitol-treatment, apoptosis was induced comparably in all cell lines examined. Cell death in MKN-1, MKN-28 or MKN-74 proceeded in a biphasic manner, while cell death in KATO-III was monophasic. The cell death partially depended on caspase activity. Treatments with sorbitol in combination with 12-O-tetradecanoylphorbol-13-acetate (TPA) markedly suppressed the apoptotic cell death, suggesting a role of protein kinase-C-dependent process. To our knowledge, this is the most rapid induction of apoptosis in human gastric cancer cells reported to date.     

Piceatannol promotes apoptosis via up-regulation of microRNA-129 expression in colorectal cancer cell lines

Piceatannol, a naturally occurring analog of resveratrol, has been confirmed as an antitumor agent by inhibiting proliferation, migration, and metastasis in diverse cancer. However, the effect and mechanisms of piceatannol on colorectal cancer (CRC) have not been well understood. This study aimed to test whether piceatannol could inhibit growth of CRC cells and reveal its underlying molecular mechanism.     

Enantiomeric neolignans from Picrasma quassioides exhibit distinctive cytotoxicity on hepatic carcinoma cells through ROS generation and apoptosis induction

Three pairs of enantiomeric neolignans 1a/1b–3a/3b were isolated from the stems of Picrasma quassioides, and separated successfully by chiral-phase HPLC. Their structures were established by comprehensive spectroscopic analyses as well as ECD spectroscopy. The in vitro cytotoxicity of the isolates was evaluated against human hepatocellular carcinoma HepG2 and Hep3B cells. Among them, 1 and its enantiomers 1a/1b, 3 and 3a/3b displayed similar cytotoxicity in pair-wise comparison against HepG2 and Hep3B cells, and the similar effects of 2 and 2a/2b were found in Hep3B cells. Interestingly, 2a and 2b had different cytotoxic activities on HepG2 cells with IC₅₀ values of 35.6?μM and 104.4?μM, respectively. In addition, 2 exerted middle cytotoxicity against HepG2 cells with an IC₅₀ value of 78.6?μM. The different cytotoxicity between enantiomers 2a and 2b attracted our interest. To investigate the underlying mechanisms responsible for the distinct cytotoxicity, we further assessed the effects of 2a and 2b on cell cycle distribution, cell apoptosis and reactive oxygen species (ROS) generation. The results indicated that 2a had more significant effect than 2b on apoptosis induction and ROS generation, but both had no obvious effect on cell cycle of HepG2 cells. It is concluded that the different configurations of 2a/2b determined the enantioselective cytotoxicity on HepG2 cells through apoptosis induction and ROS generation.     

Hyperthermia enhances bortezomib-induced apoptosis in human white blood cancer cells

At present, the current therapeutic strategy for apoptosis induction mainly relies on the administration of pharmacological apoptotic modulators. Apart from that, apoptosis can be induced by various external stimuli such as hyperthermia, ionizing radiation, and electric fields. Despite advantages, both physical and pharmacological approaches bear some limitations as well. The rationale of this study was to overcome the limitations by combining hyperthermia and apoptotic modulator ‘bortezomib’ (Velcade). Two types of human blood cancer cell lines were utilized: human leukemic monocyte lymphoma cell U937 line and peripheral blood mononuclear cells (PMBCs) derived from the patient diagnosed with acute myeloid leukemia. Prior to apoptosis experiments, cytotoxicity tests were performed at three types of temperature regimes (40 °, 42 ° and 44 °C). We observed a gradual inhibition of cell viability correlating with an increase of temperature and drug concentration in both cell lines. However, there was no significant difference between sham group and groups of leukemic PMBCs treated by high temperature (44 °C) and bortezomib. In U937 cells, combined treatment by heat shock and bortezomib led to an increase the number of cells underwent the late apoptosis stage. At the same time, similar treatment of PMBCs resulted in the stimulation of early apoptosis. Our data suggest that combination of bortezomib and hyperthermia enhances apoptosis induction in human cancer white blood cells, indicating a therapeutic potential for blood cancer therapy.     

Viridiflorol induces anti-neoplastic effects on breast,lung, and brain cancer cells through apoptosis

All active natural molecules are not fully exploited as therapeutic agents, causing delays in the advancement of anticancer drug discovery. Viridiflorol is a natural volatile element that may work as anti-cancer compound. We tested the anticancer properties of viridiflorol at different concentrations ranging from 0.03 to 300 μM in vitro on three cancer cells including breast (MCF-7), lung (A549) and brain (Daoy). The cancer cells responses were documented after treatment using MTT and Annexin V assays. Viridiflorol showed cytotoxic effects against all tested cell lines, reducing cell viability in a concentration-dependent manner with variable IC₅₀ values. Daoy and A549 cell lines were more sensitive to viridiflorol when compared with temozolomide and doxorubicin, respectively. Viridiflorol demonstrated the highest anticancer activity against the Daoy cells with an estimated IC₅₀ of 0.1 µM followed by MCF-7 at 10 µM, and A549 at 30 µM. In addition, upon exposure to concentrations ranging from 30 µM to 300 µM of viridiflorol, early and late apoptotic cell death was induced in a concentration dependent manner in Daoy (55.8%-72.1%), MCF-7 (36.2%-72.7%) and A459 (35%-98.9%) cell lines, respectively. In conclusion, viridiflorol demonstrates cytotoxic and apoptotic ability in three different cancer cell lines (brain, breast and lung).     

New betulinic acid derivatives induce potent and selective antiproliferative activity through cell cycle arrest at the S phase and caspase dependent apoptosis in human cancer cells

New semisynthetic derivatives of betulinic acid (BA) RS01, RS02 and RS03 with 18-45 times improved cytotoxic activity against HepG2 cells, were tested for their ability to induce apoptosis and cell cycle arrest in HepG2, HeLa and Jurkat cells. All the compounds induced significant increase in the population at the S phase more effectively than BA. RS01, RS02 and RS03 were also found to be potent inducers of apoptosis with RS01 being markedly more potent than BA, suggesting that the introduction of the imidazolyl moiety is crucial for enhancing the induction of apoptosis and the cell cycle arrest. The mechanism of apoptosis induction has been studied in HepG2 cells and found to be mediated by activation of the postmitochondrial caspases-9 and -3 cascade and possibly by mitochondrial amplification loop involving caspase-8. These facts were corroborated by detection of mitochondrial cytochrome c release and DNA fragmentation. Because RS01, RS02 and RS03 exhibited significant improved antitumor activity with respect to BA, they may be promising new agents for the treatment of cancer. In particular, RS01 is the most promising compound with an IC₅₀ value 45 times lower than BA on HepG2 cells and 61 times lower than the one found for the non-tumoral Chang liver cells.     

Anti-cancer effect of Cassia auriculata leaf extract in vitro through cell cycle arrest and induction of apoptosis in human breast and larynx cancer cell lines

The in vitro anti-cancer effect of Cassia auriculata leaf extract (CALE) was evaluated in human breast adenocarcinoma MCF-7 and human larynx carcinoma Hep-2 cell lines. CALE preferentially inhibited the growth of both the cell lines in a dose-dependent manner with IC₅₀ values of 400 and 500 μg for MCF-7 and Hep-2 cells, respectively. The results showed the anti-cancer action is due to nuclear fragmentation and condensation, associated with the appearance of A₀ peak in cell cycle analysis that is indicative of apoptosis. In addition, CALE treated MCF-7 and Hep-2 cells had decreased expression of anti-apoptotic Bcl-2 protein and increased expression of pro-apoptotic Bax protein, eventually leading a decrease in the Bcl-2/Bax ratio. These results demonstrated that CALE inhibits the proliferation of MCF-7 and Hep-2 cells through induction of apoptosis, making CALE a candidate as new anti-cancer drug.     

Stevioside mediated chemosensitization studies and cytotoxicity assay on breast cancer cell lines MDA-MB-231 and SKBR3

Cancer is one of the most impacting life-threatening disease for the human populace. Hence, over the years we have seen a consistent interest to study and investigate new treatments to cure and prevent this disease. Medicinal plants have played a progressive part in treatment since many years. In this research study, we have explored the cytotoxicity effect of purified bioactive compound isolated from Stevia rebaudiana leaves and the key mechanism responsible for apoptosis in human breast cancer cells. The anticancer properties of Stevia rebaudiana leaves has been suggested in earlier literature. Hence, the aim of this study was to investigate the cytotoxicity of purified stevioside in human breast cancer cell lines MDA-MB-231 and SKBR3. Results showed that purified stevioside inhibited the growth of cancerous cell lines. The IC50 obtained after treatment with stevioside on cancer cells MDA-MB-231 and SKBR3 are 55 µM and 66 µM respectively. This shows purified stevioside is capable of inducing apoptosis indicating its promising anticancer activity. However, so far chemosensitization effects of stevioside on breast cancer have not been fully explained by other studies. Hence, additionally, this study also evaluates the chemosensitization potential of stevioside in combination with 5-FU. This research study shows the importance of Stevia rebaudiana as a good source of bioactive compounds with high anti-cancer property.     

Natural static magnetic field-induced apoptosis in liver cancer cell

Purpose: To observe the apoptotic effects of NSMF on human hepatoma cells and to investigate the mechanisms. Materials and methods: Human hepatoma cell line Bel-7402 and Hep G-2 were treated by 0.2?T rotary NSMF (30?min/d) with 250?Hz, 400?Hz and 500?Hz for 3?d and 6?d, respectively. Apoptosis was analyzed with flow cytometry. Cell proliferation was measured with XTT assay. Expression of Bcl-2, caspase3/8/9 was analyzed with ELISA. Results: After 6?d treatment, significant apoptosis was induced by 400?Hz in Bel-7402 cells. Slight cell apoptosis was observed at 250?Hz, while Hep G-2 cells exhibited slight apoptosis at 250?Hz and 400?Hz. After 3?d treatment, no apoptosis exhibited in both cell types. Compared with control group, expression of Bcl-2 and Caspase 8 in treated Bel-7402 cells were significantly reduced (p?p?Conclusions: NSMF upregulates caspase 9 and downregulates Bel-2 expression, which results in higher level of active caspase 3 to trigger apoptosis in cells. Different cell types require different NSMF factors like rotary frequency and treatment time to induce apoptosis.     

Progestin inhibition of cell death in human breast cancer cell lines

Previously, we have shown that progestins both stimulate proliferation of the progesterone receptor (PR)-rich human breast cancer cell line T47D and protect from cell death, in charcoal-stripped serum-containing medium. To lessen the variability inherent in different preparations of serum, we decided to further characterize progestin inhibition of cell death using serum starvation to kill the cells, and find that progestins protect from serum-starvation-induced apoptosis in T47D cells. This effect exhibits specificity for progestins and is inhibited by the antiprogestin RU486. While progestin inhibits cell death in a dose–responsive manner at physiological concentrations, estradiol-17β surprisingly does not inhibit cell death at any concentration from 0.001 nM to 1 μM. Progestin inhibition of cell death also occurs in at least two other human breast cancer cell lines, one with an intermediate level of PR, MCF-7 cells, and, surprisingly, one with no detectable level of PR, MDA-MB-231 cells. Further, we have found progestin inhibition of cell death caused by the breast cancer chemotherapeutic agents doxorubicin and 5-fluorouracil. These data are consistent with the building body of evidence that progestins are not the benign hormones for breast cancer they have been so long thought to be, but may be harmful both for undiagnosed cases and those undergoing treatment.     

Aclarubicin-induced ROS generation and collapse of mitochondrial membrane potential in human cancer cell lines

The cytotoxicity of aclarubicin (ACL) in A549 (human non-small lung), HepG2 (human hepatoma) and MCF-7 (human breast adenocarcinoma) cancer cell lines was evaluated and compared with that of doxorubicin (DOX). Changes in mitochondrial transmembrane potential (ΔΨ_m), and production of reactive oxygen species (ROS) of drug-treated cells were monitored. Moreover, morphological changes associated with apoptosis were examined using double staining with Hoechst 33258-propidium iodide (PI). The results showed that ACL was much more cytotoxic than DOX in all investigated cell lines. Furthermore, ACL induced a concentration- and time-dependent increase in ROS production and decrease in mitochondrial membrane potential. The drugs, especially ACL, also induced ROS mediated apoptosis and necrosis pathways in all cell lines depending on the length of the post-treatment time. All these processes were partially inhibited by the antioxidants: N-acetylcysteine (NAC) and α-tocopherol. Of both drugs, DOX caused considerably weaker depolarization of the mitochondrial membrane. Its 10-fold higher concentration, as compared to ACL, was required to induce a similar effect, in accordance with the highly distinct cytotoxicity of these drugs towards investigated cells. In conclusion, ROS production preceded a decrease in mitochondrial membrane potential, but only changes in ΔΨ_m were correlated with drug cytotoxicity in particular cell line. These results suggest that the impairment of ΔΨ_m and an increase in ROS level might be important mechanisms of ACL cytotoxicity in cancer cells in solid tumors.