Induction of Apoptosis and Regulation of MicroRNA Expression by (2E,6E)-2,6-bis-(4-hydroxy-3-methoxybenzylidene)-cyclohexanone (BHMC) Treatment on MCF-7 Breast Cancer Cells

(2E,6E)-2,6-bis-(4-hydroxy-3-methoxybenzylidene)-cyclohexanone (BHMC) is a synthetic curcumin analogue, which has been reported to possess anti-tumor, anti-metastatic, and anti-invasion properties on estrogen receptor (ER) negative breast cancer cells in vitro and in vivo. However, the cytotoxic effects of BHMC on ER positive breast cancer cells were not widely reported. This study was aimed to investigate the cytotoxic potential of BHMC on MCF-7 cells using cell viability, cell cycle, and apoptotic assays. Besides, microarray and quantitative polymerase chain reaction (qPCR) were performed to identify the list of miRNAs and genes, which could be dysregulated following BHMC treatment. The current study discovered that BHMC exhibits selective cytotoxic effects on ER positive MCF-7 cells as compared to ER negative MDA-MB-231 cells and normal breast cells, MCF-10A. BHMC was shown to promote G2/M cell cycle arrest and apoptosis in MCF-7 cells. Microarray and qPCR analysis demonstrated that BHMC treatment would upregulate several miRNAs like miR-3195 and miR-30a-3p and downregulate miRNAs such as miR-6813-5p and miR-6132 in MCF-7 cells. Besides, BHMC administration was also found to downregulate few tumor-promoting genes like VEGF and SNAIL in MCF-7. In conclusion, BHMC induced apoptosis in the MCF-7 cells by altering the expressions of apoptotic-regulating miRNAs and associated genes.     

Synthesis,characterization, and biological evaluation of doxorubicin containing silk fibroin micro- and nanoparticles

The aim of this study was biological evaluation of doxorubicin containing silk fibroin micro- and nanoparticles (Dox-MF and Dox-NF). Dox-MF and Dox-NF were synthesized. Cell toxicity on MCF-7, Saos2, and HFF cells was assessed using MTT assay. Induced apoptosis was assessed using flow cytometry and staining with PI/annexin V. Production of reactive oxygen species (ROS) was measured. Gene expression of p53 was evaluated by real-time PCR. FTIR, SEM, and DLS confirmed the accurate synthesis. Cytotoxicity of Dox-MF and Dox-NF showed significant inhibition of cell growth compared with the controls. Regarding Dox-NF, a significant increase was seen in mRNA level of P53 in MCF-7 and SAOS-2 ​cells and a significant decrease in HFF cells compared to the controls. There was a significantly higher expression of P53 gene in MCF-7 and HFF cells treated by Dox-MF. However, a significant decrease in P53 gene expression was detected in SAOS-2 ​cells. Significant apoptotic induction of cell lines by Dox-MF and Dox-NF was observed in both early and late stages. Dox-MF and Dox-NF acted in the direction of cell death through the apoptotic pathway and changing p53 gene expression. So, Dox-MF and Dox-NF can be considered as a candidate for new anticancer agents.     

Chitinase inhibits growth of human breast and colorectal cancer cells in vitro and Ehrlich ascites carcinoma cells in vivo

Trichosanthes dioica seed extract was loaded on a QA-cellulose column and the unbound fraction with the chitinase activity was run on SDS-PAGE. Multiple bands were observed and were separated by a Sephadex G-50 column. The combination of the 6 and 33 kDa masses supported the degradation of chitinase as purified earlier. Only the 33 kDa fraction contained sugar and showed chitinase activity. The chitinase was also isolated by using a chitin column. At 200 µg/ml protein concentration, the chitinase inhibited 49.1 %, 48.8 % and 38.12 % of Ehrlich ascites carcinoma, HCT-116 and MCF-7 cells growth, respectively, in a dose-dependent manner. Exactly, 46 % and 82 % EAC cell growth inhibition were observed after treating the EAC cells bearing Swiss albino mice with the chitinase at the doses of 1.0 and 2.0 mg/Kg/day respectively. EAC, HCT-116 and MCF-7 cells growth inhibitions were due to the induction of apoptosis. ROS was accumulated in HCT-116 and MCF-7 cells. After treatment of HCT-116 cells, the expression level of p53 and TNFα genes increased and PARP gene decreased. On the other hand, elevated expression was observed for PARP, MAPK, NFκB, FAS, FADD, and Caspase-8 genes in MCF-7 cells. The induction of apoptosis in HCT-116 was further confirmed by caspase protein expression. The chitinase causes ‘S’ cell cycle arrest in MCF-7 and HCT-116 cells. T. dioica seed chitinase inhibited EAC, HCT-116 and MCF-7 cells by inducing apoptosis in vitro and EAC in vivo in mice. These promising results indicated that T. dioica seed chitinase can be an anticancer agent.     

The Antiproliferative and Apoptotic Effect of a Novel Synthesized S-Triazine Dipeptide Series,and Toxicity Screening in Zebrafish Embryos

Several derivatives containing morpholine/piperidine, anilines, and dipeptides as pending moieties were prepared using s-triazine as a scaffold. These compounds were evaluated for their anticancer activity against two human breast cancer cell lines (MCF-7 and MDA-MB-231), a colon cancer cell line (HCT-116), and a non-tumorigenic cell line (HEK 293). Tamoxifen was used as a reference. Animal toxicity tests were carried out in zebrafish embryos. Most of these compounds showed a higher activity against breast cancer than colon cancer. Compound 3a—which contains morpholine, aniline, and glycylglycinate methyl ester—showed a high level of cytotoxicity against MCF-7 cells with IC₅₀ values of less than 1 µM. This compound showed a much lower level of toxicity against the non-tumorigenic HEK-293 cell line, and in the in vivo studies using zebrafish embryos. Furthermore, it induced cell cycle arrest at the G2/M phase, and apoptosis in MCF-7 cells. On the basis of our results, 3a emerges as a potential candidate for further development as a therapeutic drug to treat hormone receptor-positive breast cancer.     

Functional characterization of human oncoprotein gankyrin in Zebrafish

Gankyrin is an oncoprotein containing seven ankyrin repeats that is overexpressed in hepatocellular carcinoma (HCC). Gankyrin binds to Mdm2, which results in accelerated ubiquitylation via degradation of p53, and it also plays an important role in cell proliferation. However, little is known about the relationships between p53 levels, cell proliferation, and gankyrin over-expression. In order to investigate the influence of gankyrin protein on p53 and Mdm2 in a zebrafish model, we injected human gankyrin (hgankyrin) containing expression vectors (pCS2-hgankyrin, pCS2-hgankyrin-EGFP) into zebrafish embryos. To measure p53 and Mdm2 expression in hgankyrin-injected embryos, RT-PCR, Northern blot and in-situ hybridization and BrdU immunostaining were used. In addition, to know the effect of hgankyrin on cell proliferation in vitro, cell viability assays such as MTT, trypan blue staining and RT-PCR following transfection of hgankyrin-containing vector into HEK 293 cell line were performed. In vivo results indicated that p53 mRNA levels decreased but those of Mdm2 were not decreased in the presence of hgankyrin. These results suggest that gankyrin downregulates p53 expression and not Mdm2 expression. In the study of cell proliferation, BrdU-positive cells were predominantly increased in the head and tail regions in hgankyrin-injected zebrafish. Additional in vitro studies using trypan blue staining and MTT assay showed that gankyrin-expressing HEK 293 cells proliferated at a faster rate, indicating that gankyrin promotes cell proliferation. Our results demonstrate that hgankyrin overexpression downregulates p53 expression and promotes cell proliferation in zebrafish. Gankyrin may play an important role in tumorigenesis via its effects on p53 and cell proliferation.     

Valtrate from Valeriana jatamansi Jones induces apoptosis and inhibits migration of human breast cancer cells in vitro

Abstract

Valtrate is a principle compound isolated from Valeriana jatamansi Jones, a traditional Chinese folk medicine originally used to treat various nervous disorders. Here, we found that valtrate exhibited significant anti-cancer activity in vitro, especially in human breast cancer cells, while displayed relatively low cytotoxicity to normal human breast epithelial cells (MCF 10A). Valtrate induced cell cycle arrest at G2/M stage and apoptosis in MDA-MB-231 and MCF-7 cells, with reduced expression of p-Akt (Ser 473), cyclin B1 and caspase 8, and increased expression of p21, p-cdc2, cleaved-caspase 3, cleaved-caspase 7 and poly (ADP-ribose) polymerase (PARP). In addition, valtrate inhibited cell migration through down-regulation of MMP-9 and MMP-2 expression. These results demonstrate that valtrate possesses anti-breast cancer activities via cell cycle arrest, apoptosis, and inhibition of cell migration, thus supporting valtrate as a potential antitumor agent.     

Synthesis and Antitumor Activity of a New 7-Azaindole Derivative

We designed and synthesized a 7-azaindole derivative（TH1082）, which was characterized by 1^H NMR and 13^C-NMR. We investigated its antitumor effects on human melanoma A375 cells, human liver cancer SMMC cells and human breast cancer MCF-7 cells in vitro via 3-（4,5-dimethyldiazol-2-yl）-2,5-diphenyl-tetrazolium bromide （MTT） assay and also explored the mechanism of antiproliferation of them. The results show that TH1082 significantly inhibited the proliferation of these cells to different extent. The IC50 values for A375 cells, SMMC cells and MCF-7 cells were 25.38, 48.70 and 76.94 μg/mL at 24 h, respectively. To observe cell morphological changes, acridine orange/ethidium bromide（AO/EB） staining and Hoechest33342/Pl staining were carried out. These results indicate that TH1082 could induced the apoptosis of A375 cells. The apoptotic rates were （9.5±2.09）%, （18.9±2.25）% and （39.5±2.02）%（5, 10 and 20 μg/mL） for A375, SMMC and MCF-7 cell lines, respectively. Further, we determined the activities of caspase-3 and caspase-9 in A375 cells treated with TH1082 at different concentrations（0, 5, 10 and 20 μg/mL） or Z-VAD-FMK（20 μmol/L）, a pan-caspase inhibitor for 24 h. The results show that TH1082 activated caspase-3 and caspase-9, and the activation could be blocked by Z-VAD-FMK. Taken together, these findings indicate that TH 1082 could inhibit the proliferation ofA375 cells via activating caspase-3 and caspase-9.     

Expression of GD3 synthase modifies ganglioside profile and increases migration of MCF-7 breast cancer cells

B- and c-series of gangliosides are over-expressed in neuro-ectoderm-related cancers, including breast cancer. It has been shown that G_D3 ganglioside is over-expressed in about 50% of invasive ductal breast carcinoma and the G_D3 synthase (GD3S) gene displays higher expression among estrogen receptor (ER) negative breast tumors. We previously showed that GD3S expression in MDA-MB-231 breast cancer cells induces the expression of G_D2 and increased cell proliferation and migration via a G_D2-dependent activation of c-Met receptor. Here, we show that in ER-positive MCF-7 breast cancer cells, GD3S expression resulted in an increase of G_D1b, which was associated with a decrease of G_M1a and G_M2. Meanwhile, GD3S expressing MCF-7 cells exhibited an increased migration without any modification of proliferation rate. Therefore, GD3S expression can result in different modifications of both ganglioside profiles and cell phenotypes depending on breast cell types.     

Linking TPPII to the protein interaction and signalling networks

Tripeptidyl peptidase II (TPPII) is primarily considered a house-keeping exopeptidase, which contributes to the functions of the ubiquitin-proteasome system by the maintenance of the cellular amino acid homeostasis. Although functionally well-characterised in vitro and using the mammalian cell models, less is known about the molecular mechanisms of its involvement in the signalling and metabolic pathways, which mediate its cellular functions. The present protein-protein interaction network analysis identified these mechanisms involved in the adaptive and innate immunity, the metabolism of the glucose, cancer cell growth, apoptosis, cell cycle and DNA damage responses. The interaction network constructed based on the publicly available protein-protein interaction data was extended by the application GeneMania, which was further used for the pathway enrichment, the protein function prediction and the protein node prioritisation analysis. The analysis suggested that the molecular mechanisms linked to the adaptive and innate immunity (ID, Kit receptor, BCR, IL-2 and G-CSF signalling; the regulation of NFκB), the aerobic glycolysis (ID and IL-2 signalling), tumorigenesis (TGF-β and p53 signalling; the top priority nodes MAPKs, mTOR regulation), diabetes (Kit receptor signalling; the top priority node GSK3β) and neurodegeneration (the control of mTOR and Aβ peptide degradation) are controlling the resulting TPPII interaction network. The uncharacterized interactions with two lung cancer suppressors (DOK3, DENND2D), a protein involved in the increased risk of the lung cancer in smokers (CYP1A1) and a protein implicated in asthmatic reactions (CHIA) suggest potential roles of TPPII in the lung cancer pathology. The interactions with methyltransferase CARNMT1, which modifies di- and tripeptides and the xenobiotic processing enzyme CYP1A1, are additional candidates for the breakthrough in new functions discovery of TPPII.     

Malformin-A1 (MA1) Sensitizes Chemoresistant Ovarian Cancer Cells to Cisplatin-Induced Apoptosis

High-grade epithelial ovarian cancer is a fatal disease in women frequently associated with drug resistance and poor outcomes. We previously demonstrated that a marine-derived compound MalforminA1 (MA1) was cytotoxic for the breast cancer cell line MCF-7. In this study, we aimed to examine the effect of MA1 on human ovarian cancer cells. The potential cytotoxicity of MA1was tested on cisplatin-sensitive (A2780S) and cisplatin-resistant (A2780CP) ovarian cancer cell lines using AlamarBlue assay, Hoechst dye, flow cytometry, Western blot, and RT-qPCR. MA1 had higher cytotoxic activity on A2780S (IC50 = 0.23 µM) and A2780CP (IC50 = 0.34 µM) cell lines when compared to cisplatin (IC50 = 31.4 µM and 76.9 µM, respectively). Flow cytometry analysis confirmed the cytotoxic effect of MA1. The synergistic effect of the two drugs was obvious, since only 13% of A2780S and 7% of A2780CP cells remained alive after 24 h of treatment with both MA1 and cisplatin. Moreover, we examined the expression of bcl2, p53, caspase3/9 genes at RNA and protein levels using RT-qPCR and Western blot, respectively, to figure out the cell death mechanism induced by MA1. A significant down-regulation in bcl2 and p53 genes was observed in treated cells compared to non-treated cells (p < 0.05), suggesting that MA1 may not follow the canonical pathway to induce apoptosis in ovarian cancer cell lines. MalforminA1 showed promising anticancer activity by inducing cytotoxicity in cisplatin-sensitive and cisplatin-resistant cancer cell lines. Interestingly, a synergistic effect was observed when MA1 was combined with cisplatin, leading to it overcoming its resistance to cisplatin.     

Synthesis of chalcones with anticancer activities

Several chalcones were synthesized and their in vitro cytotoxicity against various human cell lines, including human breast adenocarcinoma cell line MCF-7, human lung adenocarcinoma cell line A549, human prostate cancer cell line PC3, human adenocarcinoma cell line HT-29 (colorectal cancer) and human normal liver cell line WRL-68 was evaluated. Most of the compounds being active cytotoxic agents, four of them with minimal IC?? values were chosen and studied in detail with MCF-7 cells. The compounds 1, 5, 23, and 25 were capable in eliciting apoptosis in MCF-7 cells as shown by multiparameter cytotoxicity assay and caspase-3/7, -8, and -9 activities (p < 0.05). The ROS level showed 1.3-fold increase (p < 0.05) at the low concentrations used and thus it was concluded that the compounds increased the ROS level eventually leading to apoptosis in MCF-7 cells through intrinsic as well as extrinsic pathways.     

Harmine Hydrochloride Mediates the Induction of G2/M Cell Cycle Arrest in Breast Cancer Cells by Regulating the MAPKs and AKT/FOXO3a Signaling Pathways

Breast cancer (BC) is one of the most common causes of death among women worldwide. Recently, interest in novel approaches for BC has increased by developing new drugs derived from natural products with reduced side effects. This study aimed to treat BC cells with harmine hydrochloride (HMH) to identify its anticancer effects and mechanisms. HMH treatment suppressed cell growth, migration, invasion, and colony formation in MCF-7 and MDA-MB-231 cells, regardless of the hormone signaling. It also reduced the phosphorylation of PI3K, AKT, and mTOR and increased FOXO3a expression. Additionally, HMH treatment increased p38 phosphorylation in MCF-7 cells and activated c-Jun N-terminal kinase (JNK) phosphorylation in MDA-MB-231 cells in a dose-dependent manner, where activated p38 and JNK increased FOXO3a expression. Activated FOXO3a increased the expression of p53, p21, and their downstream proteins, including p-cdc25, p-cdc2, and cyclin B1, to induce G2/M cell cycle arrest. Furthermore, HMH inhibited the PI3K/AKT/mTOR pathway by significantly reducing p-AKT expression in combination with LY294002, an AKT inhibitor. These results indicate that mitogen-activated protein kinases (MAPKs) and AKT/FOXO3a signaling pathways mediate the induction of cell cycle arrest following HMH treatment. Therefore, HMH could be a potential active compound for anticancer bioactivity in BC cells.     

Alterations of the exo- and endometabolite profiles in breast cancer cell lines: A mass spectrometry-based metabolomics approach

In recent years, knowledge about metabolite changes which are characteristic for the physiologic state of cancer cells has been acquired by liquid chromatography coupled to mass spectrometry. Distinct molecularly characterized breast cancer cell lines provide an unbiased and standardized in vitro tumor model reflecting the heterogeneity of the disease. Tandem mass spectrometry is a widely applied analytical platform and highly sensitive technique for analysis of complex biological samples. Endo- and exometabolite analysis of the breast cancer cell lines MDA-MB-231, -453 and BT-474 as well as the breast epithelial cell line MCF-10A has been performed using two different analytical platforms: UPLC-ESI-Q-TOF based on a scheduled precursor list has been applied for highlighting of significant differences between cell lines and HPLC-ESI-QqQ using multiple reaction monitoring has been utilized for a targeted approach focusing on RNA metabolism and interconnected pathways, respectively. Statistical analysis enabled a clear discrimination of the breast epithelial from the breast cancer cell lines. As an effect of oxidative stress, a decreased GSH/GSSG ratio has been detected in breast cancer cell lines. The triple negative breast cancer cell line MDA-MB-231 showed an elevation in nicotinamide, 1-ribosyl-nicotinamide and NAD+ reflecting the increased energy demand in triple negative breast cancer, which has a more aggressive clinical course than other forms of breast cancer. Obtained distinct metabolite pattern could be correlated with distinct molecular characteristics of breast cancer cells. Results and methodology of this preliminary in vitro study could be transferred to in vivo studies with breast cancer patients.     

Bicyclic stapled peptides based on p53 as dual inhibitors for the interactions of p53 with MDM2 and MDMX

In recent years, the strategy of inhibiting the interactions of p53 with murine double minute 2(MDM2)and murine double minute X(MDMX) has been proved to be a promising approach for tumor therapy.However, the poor proteolytical stability and low intracellular delivery efficiency of peptide inhibitors limit their clinical application. Here, we designed and synthesized the bicyclic stapled peptides based on p53 by combining all-hydrocarbon stapling and lactam stapling strategies. We demonstrated th...     

In situ evaluation of breast cancer cell growth with 3D ATR-FTIR spectroscopy

A 3D attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy is applied to the in situ monitoring of the growth of breast cancer cell (MCF-7) on a ZnSe surface. The good biocompatibility of the ZnSe crystal results in a tight adhesion of the cells on the surface, with corresponding remarkable IR signals. The series spectrum curves are corresponding to each stage of the cell growth, elucidating the distinguishing phase of the cell cycle. The characteristic absorbance bands of MCF-7 breast cancer cells shift in comparison to the spectra of breast normal cells. However, no changes are observed as compared to the spectra of dead cells with those of the live cells.     

JNK inhibitor SP600125 promotes the formation of polymerized tubulin, leading to G2/M phase arrest, endoreduplication, and delayed apoptosis

The JNK inhibitor SP600125 strongly inhibits cell proliferation in many human cancer cells by blocking cell-cycle progression and inducing apoptosis. Despite extensive study, the mechanism by which SP600125 inhibits mitosis-related effects in human leukemia cells remains unclear. We investigated the effects of SP600125 on the inhibition of cell proliferation and the cell cycle, and on microtubule dynamics in vivo and in vitro. Treatment of synchronized leukemia cells with varying concentrations of SP600125 results in significant G₂/M cell cycle arrest with elevated p21 levels, phosphorylation of histone H3 within 24 h, and endoreduplication with elevated Cdk2 protein levels after 48 h. SP600125 also induces significant abnormal microtubule dynamics in vivo. High concentrations of SP600125 (200 µM) were required to disorganize microtubule polymerization in vitro. Additionally, SP600125-induced delayed apoptosis and cell death was accompanied by significant poly ADP-ribose polymerase (PARP) cleavage and caspase-3 activity in the late phase (at 72 h). Endoreduplication showed a greater increase in ectopic Bcl-2-expressing U937 cells at 72 h than in wild-type U937 cells without delayed apoptosis. These results indicate that Bcl-2 suppresses apoptosis and SP600125-induced G₂/M arrest and endoreduplication. Therefore, we suggest that SP600125 induces mitotic arrest by inducing abnormal spindle microtubule dynamics.     

A new bioactive prenylated dihydroflavanoid from Dolichos tenuicaulis （Baker） Craib

A new prenylated dihydroflavonoid was obtained from the root of Dolichos tenuicaulis （Baker） Craib. The structure was elucidated as （2S）-5,2＇,6＇-trihydroxy-3＇″, 8-di （γ,γ-dimethyl-allyl）-2＇″, 2＇″-dimethylpyrano-[5＇″,6＇″： 6,7]-2＇″″,4＇″″-cyclohexadiene-1 ＇″″-one-[2＇″″,3＇″″： 3＇,4＇]-flavanone, named dolichnin A, by spectroscopic methods including UV, IR, HR-EI-MS, 1D NMR and 2D NMR techniques, and subsequently, the anticancer activity of this compound to inhibit human cancer cells＇ growth including A549, BEL-7402, Hep-3B, SMMC7721, HT-29, MCF-7, SGC-7902, K562, A498 and PC3 cell lines by MTT method was evaluated in vitro.     

Rhododendron molle G. Don Extract Induces Apoptosis and Inhibits Migration in Human Colorectal Cancer Cells and Potential Anticancer Components Analysis

Rhododendron molle G. Don is one example of traditional Chinese medicine with important medicinal value. In this study, the effects of methanol extract of R. molle leaves (RLE) on colorectal cancer HT-29 cells and its potential molecular mechanism were investigated. MTT analysis showed that RLE could significantly inhibit the cell viability and migration of HT-29 cells in a concentration-dependent manner. Cell cycle analyses via flow cytometer suggested that RLE induced DNA fragmentation, indicative of apoptosis, and arrest at the S phase in HT-29 cells. Quantitative real-time PCR (qRT-PCR) analysis showed that RLE could upregulate the mRNA expression of p53 and p21 in HT-29 cells, which would result in HT-29 cells being blocked in S phase. Meanwhile, RLE could upregulate the expression of Bax, and downregulate the expression of Bcl-2, which would induce cell apoptosis. Further western blot analysis showed that the protein expression changes of Bax and P53 were basically consistent with the results of qRT-PCR. In addition, GC-MS analysis detected 17 potential anticancer components in R. molle. These results indicate that R. molle has significant anticancer activity, which provides some useful information for further study and clinical application for R. molle.     

m-THPC-Mediated Photodynamic Therapy (PDT) Does Not Induce Resistance to Chemotherapy, Radiotherapy or PDT on Human Breast Cancer Cells In Vitro

Photodynamic therapy (PDT) uses laser light to activate a photosensitizer that has been absorbed preferentially by cancer cells after systemic administration. A photo-toxic reaction ensues resulting in cell death and tissue necrosis. Some cells, however, may survive PDT. This study was performed to determine if surviving human breast cancer cells (MCF-7) can become resistant to PDT, chemotherapy or radiotherapy. The MCF-7 cells were cultured under standard conditions prior to being exposed to the photosensitizer, 5,10,15,20-meta-tet-ra(hydroxyphenyl)chlorin (zn-THPC), for 24 h and then irradiated with laser light (652 nm). Surviving cells were allowed to regrow by allowing a 2 week interval between each additional PDT. After the third and final treatment, colony formation assays were used to evaluate the sensitivity of cultured cells to ionizing radiation and PDT and the ATP cell viability assay tested in vitro chemosen-sitivity. Flow cytometry was used to analyze the cell cycle. No alterations in the cell cycle were observed after three cycles of PDT with m-THPC. Similar responses to chemotherapy and ionizing radiation were seen in control and treatment groups. The m-THPC-sensitized PDT did not induce resistance to subsequent cycles of PDT, chemo- or radiotherapy. Photodynamic therapy with m-THPC may represent a novel adjunctive treatment of breast cancer that may be combined with surgery, chemotherapy or ionizing radiation.     

Semi-Synthesis of Small Molecules of Aminocarbazoles: Tumor Growth Inhibition and Potential Impact on p53

The tumor suppressor p53 is inactivated by mutation in approximately 50% of human cancers. Small molecules that bind and stabilize those mutants may represent effective anticancer drugs. Herein, we report the tumor cell growth inhibitory activity of carbazole alkaloids and amino derivatives, as well as their potential activation of p53. Twelve aminocarbazole alkaloids were semi-synthesized from heptaphylline (1), 7-methoxy heptaphylline (2), and 7-methoxymukonal (3), isolated from Clausena harmandiana, using a reductive amination protocol. Naturally-occurring carbazoles 1–3 and their amino derivatives were evaluated for their potential effect on wild-type and mutant p53 activity using a yeast screening assay and on human tumor cell lines. Naturally-occurring carbazoles 1–3 showed the most potent growth inhibitory effects on wild-type p53-expressing cells, being heptaphylline (1) the most promising in all the investigated cell lines. However, compound 1 also showed growth inhibition against non-tumor cells. Conversely, semi-synthetic aminocarbazole 1d showed an interesting growth inhibitory activity in tumor cells expressing both wild-type and mutant p53, exhibiting low growth inhibition on non-tumor cells. The yeast assay showed a potential reactivation of mutant p53 by heptaphylline derivatives, including compound 1d. The results obtained indicate that carbazole alkaloids may represent a promising starting point to search for new mutp53-reactivating agents with promising applications in cancer therapy.