Development of EphA2 siRNA-loaded lipid nanoparticles and combination with a small-molecule histone demethylase inhibitor in prostate cancer cells and tumor spheroids.

BACKGROUND: siRNAs hold a great potential for cancer therapy, however, poor stability in body fluids and low cellular uptake limit their use in the clinic. To enhance the bioavailability of siRNAs in tumors, novel, safe, and effective carriers are needed. RESULTS: Here, we developed cationic solid lipid nanoparticles (cSLNs) to carry siRNAs targeting EphA2 receptor tyrosine kinase (siEphA2), which is overexpressed in many solid tumors including prostate cancer. Using DDAB cationic lipid instead of DOTMA reduced nanoparticle size and enhanced both cellular uptake and gene silencing in prostate cancer cells. DDAB-cSLN showed better cellular uptake efficiency with similar silencing compared to commercial transfection reagent (Dharmafect 2). After verifying the efficacy of siEphA2-loaded nanoparticles, we further evaluated a potential combination with a histone lysine demethylase inhibitor, JIB-04. Silencing EphA2 by siEphA2-loaded DDAB-cSLN did not affect the viability (2D or 3D culture), migration, nor clonogenicity of PC-3 cells alone. However, upon co-administration with JIB-04, there was a decrease in cellular responses. Furthermore, JIB-04 decreased EphA2 expression, and thus, silencing by siEphA2-loaded nanoparticles was further increased with co-treatment. CONCLUSIONS: We have successfully developed a novel siRNA-loaded lipid nanoparticle for targeting EphA2. Moreover, preliminary results of the effects of JIB-04, alone and in combination with siEphA2, on prostate cancer cells and prostate cancer tumor spheroids were presented for the first time. Our delivery system provides high transfection efficiency and shows great promise for targeting other genes and cancer types in further in vitro and in vivo studies.

Apoptotic and anti-angiogenic effects of Salvia triloba extract in prostate cancer cell lines.

Plants, due to their remarkable composition, are considered as natural resources of bioactive compounds with specific biological activities. Salvia genus (Lamiaceae) has been used around the world in complementary medicine since ancient times. We investigated the cytotoxic, apoptotic and anti-angiogenic effects of methanolic Salvia triloba extract (STE) in prostate cancer cells. Cell viability was evaluated by XTT; apoptosis was investigated by DNA fragmentation and caspase 3/7 activity assays. Changes in the angiogenic cytokine levels were investigated by human angiogenesis antibody array. Scratch assay was used to determine the cell motility. STE induced cytotoxicity and apoptosis in a concentration-dependent manner in both cancer cells; however, it was not cytotoxic to normal cells. Cell motility was reduced in PC-3, DU-145 and HUVEC cells by STE treatment. ANG, ENA-78, bFGF, EGF, IGF-1 and VEGF-D levels were significantly decreased by -2.9, -3.7, -1.7, -1.7, -2.0 and -1.8 fold in STE-treated DU-145 cells, however, ANG, IL-8, LEP, RANTES, TIMP-1, TIMP-2 and VEGF levels were significantly decreased by -5.1, -2.0, -2.4, -3.1, -1.5, -2.0 and -2.5 fold in PC-3 cells. These data suggest that STE might be a promising candidate for anti-tumor and anti-angiogenic treatment of prostate cancer.

Combination of zoledronic acid and serine/threonine phosphatase inhibitors induces synergistic cytotoxicity and apoptosis in human breast cancer cells via inhibition of PI3K/Akt pathway.

The aim of this study was to investigate the cytotoxic and apoptotic effects of zoledronic acid (ZA) in combination with serine/threonine protein phosphatase inhibitors, calyculin-A (CA) and okadaic acid (OA), in human MCF-7 and MDA-MB-231 breast cancer cells. XTT cell viability assay was used to evaluate cytotoxicity. DNA fragmentation and caspase-3/7 activity assays were performed to evaluate apoptosis. Activities of phosphatase 1 (PP1) and phosphatase 2A (PP2A) were measured by serine/threonine phosphatase ELISA kit. Expression levels of PI3K, p-PI3K, Akt, p-Akt, Bcl-2, p-Bcl-2, Bad, and p-Bad proteins were evaluated by Western blot analysis. Combination of ZA with either CA or OA showed synergistic cytotoxicity and apoptosis as compared to any agent alone in both MCF-7 and MDA-MB-231 breast cancer cells. Combination treatment also resulted in inhibition of both PP1 and PP2A activities. Both agents used alone or in combination did not induce significant changes in total PI3K, Akt, Bcl-2, and Bad expressions, while p-PI3K, p-Akt, p-Bcl-2, and p-Bad levels were reduced by the combination treatment as compared to agents alone. Moreover, apoptotic effect of combination treatment was significantly inhibited in the presence of LY294002, a specific PI3K inhibitor, in both breast cancer cell lines. In conclusion, synergistic apoptotic effect of the combination treatment is correlated with the block of the PI3K/Akt signal pathway in breast cancer cells.

Enhanced cytotoxicity and apoptosis by thymoquinone in combination with zoledronic acid in hormone- and drug-resistant prostate cancer cell lines.

PURPOSE: Thymoquinone (TQ), an active ingredient of black seed oil (Nigella Sativa), has been shown to possess cytotoxic activity against a variety of cancer cell lines. Our purpose was to investigate if the cytotoxic and apoptotic effect of zoledronic acid (ZA) can be enhanced by the addition of the TQ in hormone- and drug-refractory prostate cancer cells PC-3 and DU-145. METHODS: XTT cell proliferation assay was used to assess cytotoxicity; DNA fragmentation and caspase 3/7 activity were also measured. RESULTS: The combination of TQ and ZA resulted in a significant synergistic cytotoxic activity and DNA fragmentation when compared to any single agent alone, in a dose- and time-dependent manner. In addition, TQ and ZA combination increased the caspase 3/7 activity in PC-3 cell line, while this activity could not be demonstrated in DU-145 cell line. CONCLUSION: TQ and ZA had minimal hematological and non-hematological toxicity profile compared to cytotoxic agents. So, this combination may be an alternative approach for patients who are unable to be treated by conventional treatments because of poor performance status.

Spatial Effects of Infiltrating T cells on Neighbouring Cancer Cells and Prognosis in Stage III CRC patients.

Colorectal cancer (CRC) is one of the most frequently occurring cancers, but prognostic biomarkers identifying patients at risk of recurrence are still lacking. In this study, we aimed to investigate in more detail the spatial relationship between intratumoural T cells, cancer cells, and cancer cell hallmarks, as prognostic biomarkers in stage III colorectal cancer patients. We conducted multiplexed imaging of 56 protein markers at single cell resolution on resected fixed tissue from stage III CRC patients who received adjuvant 5-fluorouracil-based chemotherapy. Images underwent segmentation for tumour, stroma and immune cells, and cancer cell 'state' protein marker expression was quantified at a cellular level. We developed a Python package for estimation of spatial proximity, nearest neighbour analysis focusing on cancer cell - T cell interactions at single-cell level. In our discovery cohort (MSK), we processed 462 core samples (total number of cells: 1,669,228) from 221 adjuvant 5FU-treated stage III patients. The validation cohort (HV) consisted of 272 samples (total number of cells: 853,398) from 98 stage III CRC patients. While there were trends for an association between percentage of cytotoxic T cells (across the whole cancer core), it did not reach significance (Discovery cohort: p = 0.07, Validation cohort: p = 0.19). We next utilized our region-based nearest neighbourhood approach to determine the spatial relationships between cytotoxic T cells, helper T cells and cancer cell clusters. In the both cohorts, we found that lower distance between cytotoxic T cells, T helper cells and cancer cells was significantly associated with increased disease-free survival. An unsupervised trained model that clustered patients based on the median distance between immune cells and cancer cells, as well as protein expression profiles, successfully classified patients into low-risk and high-risk groups (Discovery cohort: p = 0.01, Validation cohort: p = 0.003).

Combination of AT-101/cisplatin overcomes chemoresistance by inducing apoptosis and modulating epigenetics in human ovarian cancer cells.

We investigated the effects of AT-101/cisplatin combination treatment on the expression levels of apoptotic proteins and epigenetic events such as DNA methyltransferase (DNMT) and histone deacetylase (HDAC) enzyme activities in OVCAR-3 and MDAH-2774 ovarian cancer cells. XTT cell viability assay was used to evaluate cytotoxicity. For showing apoptosis, both DNA Fragmentation and caspase 3/7 activity measurements were performed. The expression levels of apoptotic proteins were assessed by human apoptosis antibody array. DNMT and HDAC activities were evaluated by ELISA assay and mRNA levels of DNMT1 and HDAC1 genes were quantified by qRT-PCR. Combination of AT-101/cisplatin resulted in strong synergistic cytotoxicity and apoptosis in human ovarian cancer cells. Combination treatment reduced some pivotal anti-apoptotic proteins such as Bcl-2, HIF-1A, cIAP-1, XIAP in OVCAR-3 cells, whereas p21, Bcl-2, cIAP-1, HSP27, Clusterin and XIAP in MDAH-2774 cells. Among the pro-apoptotic proteins, Bad, Bax, Fas, phospho-p53 (S46), Cleaved caspase-3, SMAC/Diablo, TNFR1 and Cytochrome c were induced in OVCAR-3 cells, whereas, Bax, TRAILR2, FADD, p27, phospho-p53 (S46), Cleaved caspase-3, Cytochrome c, SMAC/Diablo and TNFR1 were induced in MDAH-2774 cells. Combination treatment also inhibited both DNMT and HDAC activities and also mRNA levels in both ovarian cancer cells. AT-101 exhibits great potential in sensitization of human ovarian cancer cells to cisplatin treatment in vitro, suggesting that the combination of AT-101 with cisplatin may hold great promise for development as a novel chemotherapeutic approach to overcome platinum-resistance in human ovarian cancer.

Effects of Thymus serpyllum extract on cell proliferation, apoptosis and epigenetic events in human breast cancer cells.

Thymus (T.) serpyllum (wild thyme) is an aromatic medicinal plant due to its several biological properties, including anticancer activity. Breast cancer is one of the most common malignancies and increasing evidence supports that it is not only a genetic but also an epigenetic disease. Epigenetics investigates changes in gene expression caused by mechanisms that do not involve alterations in DNA sequence. DNA methylation and histone acetylation are the most widely studied epigenetic changes in cancer cells. This study evaluated the effects of T. serpyllum on apoptosis and epigenetic events in breast cancer cells. XTT cell viability assay was used to determine cytotoxicity. DNA fragmentation and caspase 3/7 activity assays were used in the assesment of apoptosis. DNA methyltransferase (DNMT) and histone deacetylase (HDAC) activities were evaluated by ELISA and verified by qRT-PCR. T. serpyllum extract induced significant cytotoxicity in breast cancer cells (MCF-7 and MDA-MB-231) but not in normal cells. It also induced apoptosis and inhibited the DNMT and HDAC activities in MDA-MB-231 cells. In the present study, the first preliminary data on the effects of the methanolic extract of T. serpyllum in normal and breast cancer cells were obtained and suggest that T. serpyllum may be a promising candidate in the development of novel therapeutic drugs for breast cancer treatment.

Fluorescence Time-lapse Imaging of Entosis Using Tetramethylrhodamine Methyl Ester Staining.

Entosis is a process where a living cell launches an invasion into another living cell's cytoplasm. These inner cells can survive inside outer cells for a long period of time, can undergo cell division, or can be released. However, the fate of most inner cells is lysosomal degradation by entotic cell death. Entosis can be detected by imaging a combination of membrane, cytoplasmic, nuclear, and lysosomal staining in the cells. Here, we provide a protocol for detecting entosis events and measuring the kinetics of entotic cell death by time-lapse imaging using tetramethylrhodamine methyl ester (TMRM) staining. This protocol was validated in: J Cell Biol (2021), DOI: 10.1083/jcb.202010030.

TRAIL signaling promotes entosis in colorectal cancer.

Entosis is a form of nonphagocytic cell-in-cell (CIC) interaction where a living cell enters into another. Tumors show evidence of entosis; however, factors controlling entosis remain to be elucidated. Here, we find that besides inducing apoptosis, TRAIL signaling is a potent activator of entosis in colon cancer cells. Initiation of both apoptosis and entosis requires TRAIL receptors DR4 and DR5; however, induction of apoptosis and entosis diverges at caspase-8 as its structural presence is sufficient for induction of entosis but not apoptosis. Although apoptosis and entosis are morphologically and biochemically distinct, knockout of Bax and Bak, or inhibition of caspases, also inhibits entotic cell death and promotes survival and release of inner cells. Analysis of colorectal cancer tumors reveals a significant association between TRAIL signaling and CIC structures. Finally, the presence of CIC structures in the invasive front regions of colorectal tumors shows a strong correlation with adverse patient prognosis.

Molecular subtype-specific responses of colon cancer cells to the SMAC mimetic Birinapant.

Colorectal cancer is a molecularly heterogeneous disease. Responses to genotoxic chemotherapy in the adjuvant or palliative setting vary greatly between patients, and colorectal cancer cells often resist chemotherapy by evading apoptosis. Antagonists of an inhibitor of apoptosis proteins (IAPs) can restore defective apoptosis signaling by degrading cIAP1 and cIAP2 proteins and by inhibition of XIAP. Due to the multiple molecular mechanisms-of-action of these targets, responses to IAP antagonist may differ between molecularly distinct colon cancer cells. In this study, responses to the IAP antagonist Birinapant and oxaliplatin/5-fluorouracil (5-FU) were investigated in 14 colon cancer cell lines, representing the consensus molecular subtypes (CMS). Treatment with Birinapant alone did not result in a substantial increase in apoptotic cells in this cell line panel. Annexin-V/PI assays quantified by flow cytometry and high-content screening showed that Birinapant increased responses of CMS1 and partially CMS3 cell lines to oxaliplatin/5-FU, whereas CMS2 cells were not effectively sensitized. FRET-based imaging of caspase-8 and -3 activation validated these differences at the single-cell level, with CMS1 cells displaying sustained activation of caspase-8-like activity during Birinapant and oxaliplatin/5-FU co-treatment, ultimately activating the intrinsic mitochondrial apoptosis pathway. In CMS2 cell lines, Birinapant exhibited synergistic effects in combination with TNFα, suggesting that Birinapant can restore extrinsic apoptosis signaling in the context of inflammatory signals in this subtype. To explore this further, we co-cultured CMS2 and CMS1 colon cancer cells with peripheral blood mononuclear cells. We observed increased cell death during Birinapant single treatment in these co-cultures, which was abrogated by anti-TNFα-neutralizing antibodies. Collectively, our study demonstrates that IAP inhibition is a promising modulator of response to oxaliplatin/5-FU in colorectal cancers of the CMS1 subtype, and may show promise as in the CMS2 subtype, suggesting that molecular subtyping may aid as a patient stratification tool for IAP antagonists in this disease.

Gingival crevicular fluid and salivary HIF-1α, VEGF, and TNF-α levels in periodontal health and disease.

BACKGROUND: Hypoxia-inducible factor-1 alpha (HIF-1α) is expressed as an adaptive response to hypoxia, mediates angiogenesis through the expression of vascular endothelial growth factor (VEGF) and can be induced by tumor necrosis factor-alpha (TNF-α). This study aimed to investigate the gingival crevicular fluid (GCF) and salivary HIF-1α, VEGF, and TNF-α levels in periodontal health and disease. METHODS: A total of 87 individuals, 20 generalized aggressive periodontitis (G-AgP), 20 chronic periodontitis (CP), 26 gingivitis patients, and 21 periodontally healthy individuals, were included. Clinical periodontal parameters were recorded; GCF and salivary samples were collected; and HIF-1α, VEGF, and TNF-α levels were measured by enzyme-linked immunosorbent assay. Nonparametric tests were used for the statistical analyses. RESULTS: G-AgP and CP groups had significantly higher GCF HIF-1α, VEGF, and TNF-α total amounts than gingivitis and healthy groups (P < 0.05). GCF HIF-1α and TNF-α total amounts in gingivitis group were significantly higher than the healthy group (P < 0.05). GCF and salivary concentrations of biomarkers were similar in both periodontitis groups (P > 0.05). Salivary HIF-1α concentrations in gingivitis group were significantly higher than G-AgP and healthy groups (P < 0.05). GCF HIF-1α, VEGF, and TNF-α total amounts were positively correlated with the site-specific clinical periodontal parameters and with each other (P < 0.05). CONCLUSIONS: HIF-1α is detectable in GCF and saliva of periodontally diseased and healthy individuals, and the GCF levels of the biomarker can be affected by disease status. Increased GCF HIF-1α, VEGF, and TNF-α levels in both chronic and aggressive form of periodontitis might suggest the role of TNF-α/HIF-1α/VEGF pathway in the pathogenesis of periodontal diseases.

The evaluation of peri-implant sulcus fluid osteocalcin, osteopontin, and osteonectin levels in peri-implant diseases.

BACKGROUND: Peri-implant mucositis is an inflammation of the soft tissues surrounding an implant. Peri-implantitis refers to a process characterized by peri-implant bone loss along with an inflammation of the soft tissues. Osteocalcin, osteopontin, and osteonectin proteins are related to bone remodeling. The aim of the present study was to investigate peri-implant sulcus fluid (PISF) osteocalcin, osteopontin, and osteonectin levels in peri-implant mucositis and peri-implantitis. METHODS: Fifty-two implants with peri-implantitis, 46 implants with peri-implant mucositis, and 47 control implants were included in the study. Clinical parameters including probing depth, modified sulcus bleeding index and modified plaque index were recorded. PISF osteocalcin, osteopontin, and osteonectin levels were analyzed by ELISA kits. RESULTS: There were no significant differences in PISF osteocalcin, osteopontin, and osteonectin total amounts between healthy controls, peri-implant mucositis and peri-implantitis groups (P > 0.05). Probing depths were not correlated with PISF osteocalcin, osteopontin, and osteonectin levels in the study groups (P > 0.05). CONCLUSIONS: Soft tissue inflammation around dental implants does not cause a change in osteocalcin, osteopontin, and osteonectin levels in PISF. Also, peri-implantitis does not seem to give rise to an increase in PISF levels of osteocalcin, osteopontin, and osteonectin.

Gingival crevicular fluid and salivary resistin and tumor necrosis factor-alpha levels in obese children with gingivitis.

BACKGROUND: This study aimed to evaluate the levels of resistin and tumor necrosis factor-alpha (TNF-α) in gingival crevicular fluid (GCF) and saliva of obese children with gingivitis. METHODS: One-hundred and thirty children (65 obese and 65 normal weight; age range 8 to 12 years) were recruited for the study. The children were classified into four subgroups based on their body mass and periodontal status; 1) obese children with gingivitis (OG, n = 33); 2) obese children with healthy periodontium (OH, n = 32); 3) normal weight children with gingivitis (NWG, n = 32); 4) normal weight children with healthy periodontium (NWH, n = 33). Body mass index (BMI) percentile, probing pocket depth (PPD), gingival index (GI), and plaque index (PI) were recorded. Resistin and TNF-α were analyzed in GCF and saliva samples by ELISA. RESULTS: Obese children had higher BMI percentiles than normal weight children (p < 0.0001). PPD, GI, PI, GCF volume, GCF, and salivary resistin and TNF-α levels were similar between obese and normal weight children (P > 0.05). OG and NWG subgroups had significantly higher GI, PI, GCF volume, GCF resistin total amounts, and salivary resistin concentrations but lower GCF resistin and TNF-α concentrations than OH and NWH (P < 0.0001 for all). GCF resistin total amounts were positively correlated with GI, PI, and GCF TNF-α total amounts (P < 0.05). CONCLUSIONS: To our knowledge, this is the first study evaluated the levels of resistin in GCF and saliva of children. Obesity is not associated with GCF and salivary resistin and TNF-α levels in children in the presence of gingival inflammation.

Evaluation of the gingival inflammation in pregnancy and postpartum via 25-hydroxy-vitamin D3, prostaglandin E2 and TNF-α levels in saliva.

BACKGROUND: Physiological changes and immunological modifications occur during pregnancy. The clinical and biological features of periodontal infections are affected by pregnancy. The aim of the present study was to evaluate saliva levels of 25-hydroxy-vitamin D3 (25(OH)D3), prostaglandin E2 (PGE2) and TNF-alpha (TNF-α) in pregnancy, postpartum and non-pregnant controls. METHODS: Whole saliva samples together with full-mouth clinical periodontal recordings were obtained from 59 pregnant, 47 post partum and 70 systemically healthy non-pregnant women. Groups were also evaluated according to the periodontal health status. 25(OH)D3, PGE2 and TNF-α levels in the saliva samples were determined by enzyme-linked immunoassays. Data were statistically tested by nonparametrical tests. RESULTS: Saliva TNF-α and PGE2 levels were significantly lower and 25(OH)D3 levels were significantly higher in the pregnant group than postpartum group (p<0.0001). Saliva TNF-α and 25(OH)D3 levels were significantly higher and PGE2 levels were significantly lower in the control group than postpartum group (p<0.0001). In the pregnant healthy, gingivitis and periodontitis groups saliva TNF-α levels were significantly lower than postpartum and control counterparts (p<0.0001, p=0.032, p=0.003 and p=0.013; p=0.027; p=0.007, respectively). In control healthy, gingivitis and periodontitis groups saliva 25(OH)D3 levels were significantly higher than the postpartum counterparts (p<0.0001, p<0.0001, p=0.002, respectively). In the control healthy and gingivitis groups saliva 25(OH)D3 levels were significantly higher than pregnant healthy and gingivitis (p<0.0001). CONCLUSIONS: In conclusion, within the limits of the present study it seems that pregnancy have an effect on parameters in saliva in relation to the periodontal status of the women. Further studies are required for better understanding of the impact of periodontal diseases on pregnancy or otherwise.

Effects of Galium aparine extract on the cell viability, cell cycle and cell death in breast cancer cell lines.

ETHNOPHARMACOLOGICAL RELEVANCE: Galium species have been traditionally used for its anti-cancer, antioxidant, anti-inflammatory, antimicrobial and cardioprotective effects in the folk medicine. Galium aparine (GA) is a typical climbing plant growing widespread in Anatolia. AIM OF THE STUDY: To investigate the potential anti-proliferative and apoptotic effect of GA methanol (MeOH) extract on MCF-7 and MDA-MB-231 human breast cancer cells and MCF-10A untransformed breast epithelial cells. MATERIALS AND METHODS: First, the extract was characterized by both liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/Q-TOF/MS) and gas chromatography-mass spectrometry (GC-MS) analyses. Then, cell viability and cell cycle distribution were investigated by XTT assay and PI staining by flow cytometry, respectively. Cell death was determined by Annexin V FITC/7-AAD staining. RESULTS: A total of 14 major phytochemicals were identified by LC/Q-TOF/MS and 34 volatile compounds were determined by GC-MS. The extract was cytotoxic in both breast cancer cell lines in a concentration and time dependent manner and showed G1 block after 72h extract treatment. However, it was not cytotoxic to MCF-10A breast epithelial cells. Flow cytometry analyses revealed that apoptosis was induced in MDA-MB-231 cells; however, necrosis was induced in MCF-7 cells. CONCLUSION: Our study suggests that GA MeOH extract may have potential anti-cancer effects against breast cancer cells without impairing normal breast epithelial cells. Ability to induction of non-apoptotic cell death besides apoptotic cell death by this complex plant-derived mixture may enable the killing of apoptosis resistant breast cancer cells but further studies should be conducted to investigate the bioavailability and metabolism of it in vivo.

Docetaxel in combination with octreotide shows synergistic apoptotic effect by increasing SSTR2 and SSTR5 expression levels in prostate and breast cancer cell lines.

PURPOSE: Docetaxel (DTX) is widely used for the treatment of metastatic prostate and breast cancers. Despite the clinical success of DTX, drug-related cumulative toxicity restricts its clinical use in cancer therapy. Thus, there is an urgent need for new therapeutic options. Octreotide (OCT) is a synthetic somatostatin analog that induces apoptosis in different cancer cell lines in vitro. In this study, we investigated the possible synergistic apoptotic effects of DTX in combination with OCT in prostate and breast cancer cell lines. METHODS: The XTT cell viability assay was used to determine cytotoxicity. Apoptosis was evaluated by Cell Death Detection ELISA(Plus) Kit. The expression levels of apoptotic proteins were assessed by human apoptosis antibody array. Levels of SSTR2 and SSTR5 proteins were determined by western blot analysis. RESULTS: DTX and OCT combination induced apoptosis in both breast and prostate cancer cells in a concentration- and time-dependent manner. Moreover, combination treatment resulted in inhibition of anti-apoptotic proteins such as Bcl-2 and Bcl-xL and induction of pro-apoptotic proteins Bax, Cytochrome c and IAPs in all of the tested cancer cell lines. SSTR2 and SSTR5 protein levels were induced as compared to any agent alone. CONCLUSIONS: These results indicate that this combination treatment is a significant inducer of apoptosis in a synergistic manner in breast and prostate cancer cells. This strong synergism helps to lower the dose of DTX in both types of cancers, thus letting DTX to be used for longer periods by delaying resistance development and lesser side effects.

A diverse induction of apoptosis by trabectedin in MCF-7 (HER2-/ER+) and MDA-MB-453 (HER2+/ER-) breast cancer cells.

Trabectedin (Yondelis, ET-743), a semi synthetic tetrahydroisoquinoline alkaloid that was originally derived from the marine tunicate Ecteinascidia turbinata. The objective of this study was to investigate whether trabectedin mediated apoptosis shows any diversity in human breast cancer cell lines with different genotypes. Trabectedin induced cytotoxicity and apoptosis in both breast cancer cells in a time and concentration-dependent manner. The expression levels of the death receptor pathway molecules, TRAIL-R1/DR4, TRAIL-R2/DR5, FAS/TNFRSF6, TNF RI/TNFRSF1A, and FADD were significantly increased by 2.6-, 3.1-, 1.7-, 11.2- and 4.0-fold by trabectedin treatment in MCF-7 cells. However, in MDA-MB-453 cells, the mitochondrial pathway related pro-apoptotic proteins Bax, Bad, Cytochrome c, Smac/DIABLO, and Cleaved Caspase-3 expressions were induced by 4.2-, 3.6-, 4.8-, 4.5-, and 4.4-fold, and the expression levels of anti-apoptotic proteins Bcl-2 and Bcl-XL were reduced by 4.8- and 5.2-fold in MDA-MB-453 cells. Moreover, trabectedin treatment increased the generation of ROS in both breast cancer cells. We have shown that trabectedin causes selective activation of extrinsic and intrinsic apoptotic pathways in two genotypically different breast cancer cells. This preliminary data might guide clinicians to choose appropriate combination agents with trabectedin based on different molecular subtypes of breast cancer.