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Melanoma is one of the most dangerous malignant epidermal cancers. Natto freeze-drying extract (NFDE) and natto water extract (NWE) were isolated from natto, soybeans fermented by Bacillus subtilis natto, which were assessed as potential anti-melanoma agents. Cell cytotoxicity assays revealed significant anti-melanoma effects of NFDE and NWE in a dose-dependent manner, and exhibited low influences on normal skin cells, including Hs68, HaCaT and adipose tissue-derived stem cells (ADSCs), respectively. Through a flow cytometer assay and autophagy acridine orange staining, the cellular death phenomenon shifted from autophagy to apoptosis with the increased dosages. Reactive oxygen species (ROS) were enhanced using DCFDA (2,7-dichlorodihydrofluorescein diacetate) staining when melanoma cells were treated with the extract. NFDE and NWE treatments increase the oxidative stress of cancer cells and cause apoptosis by inhibiting AMP-activated protein kinase (AMPK). NFDE and NWE were considered to play a critical role in cell death through ROS adjustment, autophagy regulation and apoptosis promotion., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Lung cancer is listed as the most common reason for cancer-related death all over the world despite diagnostic improvements and the development of chemotherapy and targeted therapies. MicroRNAs control both physiological and pathological processes including development and cancer. A microRNA-9 to 1 (miR-9 to 1) overexpression model in lung cancer cell lines was established and miR-9 to 1 was found to significantly suppress the proliferation rate in lung cancer cell lines, colony formation in vitro, and tumorigenicity in nude mice of A549 cells. Ubiquitin-like containing PHD and RING finger domains 1 (UHRF1) was then identified to direct target of miR-9 to 1. The inhibition of UHRF1 by miR-9 to 1 causes G1 arrest and p15, p16, and p21 were re-expressed in miR-9 to 1 group in mRNA level and protein level. Silence of UHRF1 expression in A549 cells resulted in the similar re-expression of p15, p16, p21 which is similar with miR-9 to 1 infection. Therefore, we concluded that UHRF1 is a new target for miR-9 to 1 to suppress cell proliferation by re-expression of tumor suppressors p15, p16, and p21 mediated by UHRF1.

Melanoma is an aggressive cancer with high lethality. In order to find new anticancer agents, isokotomolide A (Iso A) and secokotomolide A (Sec A) isolated from Cinnamomum kotoense were identified to be potential bioactive agents against human melanoma but without strong antioxidative properties. Cell proliferation assay displayed Iso A and Sec A treated in the normal human skin cells showed high viabilities. It also verified that two of them possess strong antimelanoma effect in concentration-dependent manners, especially on B16F10, A2058, MeWo, and A375 cells. Wound healing assay presented their excellent antimigratory effects. Through 3- N ,3- N ,6- N ,6- N -Tetramethylacridine-3,6-diamine (acridine orange, AO) staining and Western blot, the autophagy induced by treatment was confirmed, including autophagy-related proteins (Atgs). By using annexin V-FITC/PI double-stain, the apoptosis was confirmed, and both components also triggered the cell cycle arrest and DNA damage. We demonstrated the correlations between the mitogen-activated protein kinase (MAPK) pathway and antimelanoma, such as caspase cascade activations. To further evaluate in vivo experiments, the inhibition of tumor cell growth was verified through the histopathological staining in a xenograft model. In this study, it was confirmed that Iso A and Sec A can encourage melanoma cell death via early autophagy and late apoptosis processes., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 Jian Li et al.)

Astaxanthin (AST) is a naturally occurring xanthophyll carotenoid having the potential to be used as an anticancer agent; however, the human body has a low bioavailability of AST due to its poor solubility in the water phase. Therefore, we applied D- α -tocopheryl polyethylene glycol succinate (TPGS) as an emulsifier and natural edible peanut oil to form a steady oil-in-water (O/W) nanoemulsion loaded with AST (denoted as TAP-nanoemulsion). TAP-nanoemulsions were stable without the droplet coalescence against thermal treatments (30-90°C), pH value changes (over a range of 2.0-8.0), and ionic strength adjustments (at NaCl concentrations of 100-500 mM) measured by dynamic light scattering (DLS). AST within TAP-nanoemulsion was released up to 80% in a simulated intestinal enzymatic fluid in vitro , and the overall recovery rate was fairly consistent in the Caco-2 cellular model. In order to further evaluate in vivo melanoma inhibitory experiments, we injected the fluorescent-stained B16F10 cells into female C57BL/6 mouse tail veins and treated TAP-nanoemulsion in an oral gavage. qRT-PCR and Western blot demonstrated that TAP-nanoemulsion triggered effectively the apoptosis pathway, including enhancements of cleaved caspase-3 and caspase-9, ataxia-telangiectasia mutated kinase (ATM), and p21WAF1/CIP1 (p21) and decreases of B-cell lymphoma 2 (Bcl-2); cyclins D, D1, and E; mitogen-activated protein kinase (MEK); extracellular signal-regulated kinases (ERK); nuclear factor κ -light-chain-enhancer of activated B cells (NF- κ B); and matrix metallopeptidase-1 and metallopeptidase-9 (MMP-1 and MMP-9) in both gene and protein expressions. In conclusion, this study suggests that TAP-nanoemulsion with the oral treatment has a positive chemotherapy effect in melanoma with lung metastases in vivo . As far as we know, this is the first time to demonstrate that an antioxidant in nanoparticle administration cures lung metastatic melanoma., Competing Interests: The authors have no competing financial interests to declare., (Copyright © 2020 Hsing-Yu Haung et al.)

Coenzyme Q 0 (CoQ 0 ; 2,3-dimethoxy-5-methyl-1,4-benzoquinone), a major active constituent of Antrodia camphorata, has been shown to inhibit human triple-negative breast cancer (MDA-MB-231) cells through induction of apoptosis and cell-cycle arrest. Ecological studies have suggested a possible association between ultraviolet B (UVB) radiation and reduction in the risk of breast cancer. However, the underlying mechanism of the combination of CoQ 0 and UVB in human estrogen receptor-positive breast cancer (MCF-7) remains unclear. In this study, the possible effect of CoQ 0 on inducing apoptosis in MCF-7 cells under exposure to low-dose UVB (0.05 J/cm 2 ) has been investigated. CoQ 0 treatment (0-35 µM, for 24-72 hours) inhibits moderately the growth of breast cancer MCF-7 cells, and the cell viability was significantly decreased when the cells were pretreated with UVB irradiation. It was noted that there was a remarkable accumulation of subploid cells, the so-called sub-G1 peak, in CoQ 0 -treated cells by using flow cytometric analysis, which suggests that the viability reduction observed after treatment may result from apoptosis induction in MCF-7 cells. CoQ 0 caused an elevation of reactive oxygen species, as indicated by dichlorofluorescein fluorescence, and UVB pretreatment significantly increased CoQ 0 -induced reactive oxygen species generation in MCF-7 cells. In addition, cells were exposed to CoQ 0 , and the induction of DNA damage was evaluated by single-cell gel electrophoresis (comet assay). CoQ 0 -induced DNA damage was remarkably enhanced by UVB pretreatment. Furthermore, CoQ 0 induced apoptosis in MCF-7 cells, which was associated with PARP degradation, Bcl-2/Bax dysregulation, and p53 expression as shown by western blot. Collectively, these findings suggest that CoQ 0 might be an important supplemental agent for treating patients with breast cancer.

Three new butanolides, isophilippinolide A, philippinolide A, and philippinolide B, and an amide, cinnaretamine, were isolated from the roots of Cinnamomum philippinense to be identified by spectroscopic analysis. Four isolated compounds were screened to examine their radical-scavenging ability, metal-chelating power, and ferric-reducing antioxidant power assay (FRAP). Cinnaretamine showed powerful antioxidative properties in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and a reducing activity; all compounds presented minor inhibition of metal-chelating capacities. The effects of anti-tyrosinase of C. philippinense constituents were determined by the level of the suppression of hydroxylation that turned from L-tyrosine to L-dopa through an in vitro mushroom tyrosinase assay, and all testing samples illustrated slight mushroom tyrosinase inhibitory properties. Isophilippinolide A exhibited inhibitory effectivenesses against the A375.S2 melanoma cell line in a cell viability assay at concentrations ranging from 0 to 200 μM for 24 h. Propidium iodide staining and flow cytometry analyses were applied to assess cell cycle accumulative distribution. It was discovered that isophilippinolide A caused sub-G1 phase accumulation in positive correlation for apoptosis to inhibit cell growth. Further investigation revealed that isophilippinolide A induced A375.S2 cells with an increase of caspase-dependent apoptotic proteins to trigger correlated pathway mechanisms according to Western blotting results. Finally, isophilippinolide A displayed only low cytotoxicities to human normal epidermal cells (melanocytes) and dermal cells (fibroblasts). Altogether, the results implied C. philippinense compounds could be considered functional ingredients in cosmetics, foods, and pharmaceutical products, particularly for their anticancer ability on human skin melanoma cells.

Sirtuins, NAD(+)-dependent deacetylases, could target both histones and nonhistone proteins in mammalian cells. Sirt1 is the major sirtuin and has been shown to involve various cellular processes, including antiapoptosis, cellular senescence. Sirt1 was reported to be overexpressed in many cancers, including lung cancer. Sirtinol, a specific inhibitor of Sirt1, has been shown to induce apoptosis of cancer cells by elevating endogenous level of reactive oxygen species. In the study, we investigated the effect of sirtinol on the proliferation and apoptosis of nonsmall cell lung cancer (NSCLC) H1299 cells. The results of proliferation assay and colony formation assay showed the antigrowth effect of sirtinol. The annexin-V staining further confirmed the apoptosis induction by sirtinol treatment. Interestingly, the levels of phosphorylated Akt and β-catenin were significantly downregulated with treating the apoptotic inducing doses. On the contrary, sirtinol treatment causes the significantly increased level of FoxO3a, a proapoptotic transcription factor targeted by Sirt1. These above results suggested that sirtinol may inhibit cell proliferation of H1299 cells by regulating the axis of Akt-β-catenin-FoxO3a. Overall, this study demonstrates that sirtinol attenuates the proliferation and induces apoptosis of NSCLC cells, indicating the potential treatment against NSCLC cells by inhibiting Sirt1 in future applications.

UV radiation from the sun is a potent environmental risk factor in the pathogenesis of skin damage. Much of the skin damage caused by ultraviolet A (UVA) irradiation from the sun is associated with oxidative stress. The aim of this study was to investigate the protective role of ellagic acid (25-75 μM), a natural antioxidant, against UVA (5-20 J/cm(2))-induced oxidative stress and apoptosis in human keratinocyte (HaCaT) cells and to reveal the possible mechanisms underlying this protective efficacy. Ellagic acid pre-treatment markedly increased HaCaT cell viability and suppressed UVA-induced ROS generation and MDA formation. Moreover, ellagic acid pre-treatment prevented UVA-induced DNA damage as evaluated by the comet assay. Ellagic acid treatment also significantly inhibited the UVA-induced apoptosis of HaCaT cells, as measured by a reduction of DNA fragmentation, mitochondria dysfunction, ER stress, caspase-3 activation, and Bcl-2/Bax deregulation. Notably, the antioxidant potential of ellagic acid was directly correlated with the increased expression of HO-1 and SOD, which was followed by the downregulation of Keap1 and the augmented nuclear translocation and transcriptional activation of Nrf2 with or without UVA irradiation. Nrf2 knockdown diminished the protective effects of ellagic acid. Therefore, ellagic acid may be useful for the treatment of UVA-induced skin damage., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

We evaluated the possible anticancer performance of a natural compound, goniothalamin (GTN), against human lung cancer using as a non-small cell lung cancer (NSCLC) cell line, H1299, as the model system. Cellular proliferation was significantly inhibited by GTN. Using an improved alkaline comet-nuclear extract (comet-NE) assay, GTN was found to induce a significant increase in the tail DNA. Wound healing and zymography assays showed that GTN attenuated cell migration and caused a reduction in the activity level of two major migration-associated matrix metalloproteinases, MMP-2 and MMP-9. It can be concluded that the DNA-damaging effect of GTN against lung cancer cells leads to growth inhibition as well as a depression in migration ability. Therefore, GTN has potential as a chemotherapeutic agent against lung cancer.

Objective: To study the effect of pGCsi-H1-APRIL on the growth of human colorectal cancer cells in transplated tumor in nude mice and to improve the effect of APRIL on proliferation and apoptosis of colorectal cancer (CRC)., Methods: Human CRC model was established in nude mice, and the nude mice were treated with APRIL siRNA twice per week for 2 weeks. APRIL mRNA expression was surveyed by PCR and APRIL protein expression was detected by immunohistochemistry. The expression of PCNA protein was detected by ELISA. The expression of bcl-2 and bcl-xl was assessed by immunohistochemical staining, and TUNEL staining was used to detect apoptosis., Results: The expression of APRIL mRNA in the APRIL siRNA group was (0.13 ± 0.05) × 10(-3), significantly lower than that in the vector group (0.95 ± 0.04) × 10(-3) and the PBS group (0.96 ± 0.05) × 10(-3). The expression of APRIL protein in the APRIL siRNA group was (87.5 ± 5.0)% lower than that in the vector and PBS groups (P < 0.05). APRIL siRNA significantly suppressed the growth of SW480 tumor: the IR (inhibitory rate) of APRIL siRNA group was (60.7 ± 1.5)% (P < 0.05). The expression of PCNA in APRIL siRNA group was (176.8 ± 18.1) ng/ml, was (56.5 ± 2.0)% lower than that of PBS group (328.4 ± 22.8) ng/ml. Furthermore, the expressions of anti-apoptosis proteins bcl-2 and bcl-xl of APRIL siRNA group were (82.6 ± 4.5)% and (79.2 ± 3.5)% lower than those of the PBS group. The apoptotic rate of the APRIL siRNA group was 40.1% ± 2.5%, significantly higher than that in the vector group (2.5 ± 0.1)% and PBS group (2.5 ± 0.2)% (P < 0.05)., Conclusion: APRIL siRNA may significantly suppress the growth and promote apoptosis in transplanted tumor of human colorectal cancer in nude mice. APRIL may become a candidate gene of gene therapy of human colorectal cancer.

Protoapigenone, isolated from the native fern plant Thelypteris torresiana, has anticancer activity against some cancer cells. However, the toxicological mechanism for protoapigenone is still unknown. Here, we investigated the anticancer effect of protoapigenone on human lung cancer cell lines. The comet assay showed that DNA damage induced by protoapigenone is dose-dependent. Trypan blue exclusion showed that the cell killing by protoapigenone is both time and dose dependent. The IC(50) of protoapigenone for 12, 24, and 48 h in H1299 cells is 6.11, 2.74, and 1.49 microM, respectively. Flow cytometry showed cell cycle perturbation such as sub-G(1) accumulation (at 1.57 microM for 48 h and at 3.57 microM for 12 and 24 h) and G(2)/M arrest (at 3.57 microM for 12 and 24 h) for protoapigenone. The sub-G(1) accumulation phenomena in the 3.57 microM for 24 h sample were shown to be apoptosis using Annexin V-immunofluorescence/propidium iodide staining. These results suggest protoapigenone is a potential chemotherapeutic agent for lung cancers.

In this study, we investigate the anticancer effect of isoobtusilactone A (IOA), a constituent isolated from the leaves of Cinnamomum kotoense, on human non-small cell lung cancer (NSCLC) A549 cells. IOA was found to induce the arrest of G2-M phase, induce apoptosis, increase sub-G1, and inhibit the growth of these cells. Further investigation revealed that IOA's blockade of the cell cycle was associated with increased levels of p21/WAF1, p27 (kip1), and p53. In addition, IOA triggered the mitochondrial apoptotic pathway, as indicated by an increase in Bax/Bcl-2 ratios, resulting in a loss of mitochondrial membrane potential, release of cytochrome c, activation of caspase-9 and caspase-3, and cleavage of PARP. We also found the generation of reactive oxygen species (ROS) to be a critical mediator in IOA-induced inhibition of A549 cell growth. In antioxidant and NO inhibitor studies, we found that by pretreating A549 cells with either N-acetylcystenine (NAC), catalase, mannitol, dexamethasone, trolox, or L-NAME we could significantly decrease IOA production of ROS. Moreover, using NAC to block ROS, we could significantly suppress IOA-induced antiproliferation, antimigration, and anti-invasion. Finally, we found that IOA inhibited the migration and invasion of A549 cell migration and invasion. Taken together, these results suggest that IOA has anticancer effects on A549 cells.

• This study examined the effects of Ganoderma tsugae extracts on lung metastatic melanoma cells in both cell culture and mouse models. The cell culture demonstrated increased oxidation levels as well as decreased cancer cell viability and migration in response to Ganoderma tsugae extract exposure in cancer cells. Additionally, when mice were induced with melanoma, then treated with the extract, rejuvenating effects were observed. Ganoderma tsugae, a medicinal mushroom and one of Taiwan's significant commercially cultivated species, contains polysaccharides and triterpenoids reported to possess anticancer effects. This study investigated the G. tsugae water extract (GTWE) for its inhibitory mechanism against lung metastatic melanoma (LMM) and B16F10 cells. The antioxidant capacity and flow cytometry showed that GTWE reduced the production of cellular reactive oxygen species dose-dependently. MTT and wound healing assays further demonstrated that GTWE suppressed melanoma cell migration and viability. qRT-PCR and western blotting verified mechanisms of apoptosis, GTWE decreased the BCL2 expressions and upregulated Bax and cleaved caspase-9 protein. These findings suggest GTWE is a potential therapeutic agent in vitro and in vivo for treating melanoma cancer. [ABSTRACT FROM AUTHOR]

Coenzyme Q0 (CoQ0; 2,3-dimethoxy-5-methyl-1,4-benzoquinone), a major active constituent of Antrodia camphorata, has been shown to inhibit human triple-negative breast cancer (MDA-MB-231) cells through induction of apoptosis and cell-cycle arrest. Ecological studies have suggested a possible association between ultraviolet B (UVB) radiation and reduction in the risk of breast cancer. However, the underlying mechanism of the combination of CoQ0 and UVB in human estrogen receptor–positive breast cancer (MCF-7) remains unclear. In this study, the possible effect of CoQ0 on inducing apoptosis in MCF-7 cells under exposure to low-dose UVB (0.05 J/cm2) has been investigated. CoQ0 treatment (0-35 µM, for 24-72 hours) inhibits moderately the growth of breast cancer MCF-7 cells, and the cell viability was significantly decreased when the cells were pretreated with UVB irradiation. It was noted that there was a remarkable accumulation of subploid cells, the so-called sub-G1 peak, in CoQ0-treated cells by using flow cytometric analysis, which suggests that the viability reduction observed after treatment may result from apoptosis induction in MCF-7 cells. CoQ0 caused an elevation of reactive oxygen species, as indicated by dichlorofluorescein fluorescence, and UVB pretreatment significantly increased CoQ0-induced reactive oxygen species generation in MCF-7 cells. In addition, cells were exposed to CoQ0, and the induction of DNA damage was evaluated by single-cell gel electrophoresis (comet assay). CoQ0-induced DNA damage was remarkably enhanced by UVB pretreatment. Furthermore, CoQ0 induced apoptosis in MCF-7 cells, which was associated with PARP degradation, Bcl-2/Bax dysregulation, and p53 expression as shown by western blot. Collectively, these findings suggest that CoQ0 might be an important supplemental agent for treating patients with breast cancer. [ABSTRACT FROM AUTHOR]

This study assessed the use of astaxanthin as an anticancer agent for increasing inhibition to melanoma cells (A375 and A2058). Wound healing and invasion assays presented that astaxanthin treatment reduced melanoma cell migration in a dose-dependent manner. The effects on melanoma cell migration were conferred via suppressed expressions of matrix metalloproteinases 1, 2 and 9. Dichlorofluorescein diacetate assay further showed that astaxanthin treatment reduced production of cellular reactive oxygen species. Cellular proliferation assay revealed potent dose-dependent inhibiting effects on melanoma cells. One-dimensional flow cytometric analysis demonstrated that astaxanthin induced cell cycle arrest in G1 phase. Mechanisms of apoptosis were verified by double fluorescence staining with annexin V-fluorescein isothiocyanate and propidium iodide. The antitumor effects of astaxanthin significantly decreased tumor size in a xenograft model. In summary, the experimental results showed that astaxanthin has potent in vivo and in vitro inhibiting effects on melanoma tumor growth for developing as chemotherapeutic agents. [ABSTRACT FROM AUTHOR]

Background: Trans-ferulic (FA) acid exhibits antioxidant effects in vitro. However, the underlying mechanism of trans-FA activity in cellular physiology, especially cancer physiology, remains largely unknown. This study investigated the cellular physiological effects of trans-FA on the H1299 human lung cancer cell line. Methods: The 2,2-diphenyl-1-picrylhydrazyl assay was used to determine free radical scavenging capability. Assessment of intracellular reactive oxygen species (ROS) was evaluated using oxidized 2',7'-dichloroluorescin diacetate and dihydroethidium staining. Trypan blue exclusion, colony formation, and anchorage-independent growth assays were used to determine cellular proliferation. Annexin V staining assay was used to assess cellular apoptosis by low cytometry. Wound healing and Boyden's well assays were used to detect the migration and invasion of cells. Gelatin zymography was used to detect matrix metalloproteinase (MMP-2 and MMP-9) activity. Western blotting was used to detect expression levels of various signaling pathway proteins. Results: DPPH assay results indicated that trans-FA exerted potent antioxidant effects. However, trans-FA increased intracellular ROS levels, including hydrogen peroxide and superoxide anion, in H1299 cells. Trans-FA treatment inhibited cellular proliferation and induced moderate apoptotic cell death at the highest concentration used (0.6 mM). Furthermore, trans-FA moderately inhibited the migration of H1299 cells at the concentrations of 0.3 and 0.6 mM and attenuated MMP-2 and MMP-9 activity. Trans-FA caused the phosphorylation of β-catenin, resulting in proteasomal degradation of β-catenin. Conversely, trans-FA treatment increased the expression of pro-apoptotic factor Bax and decreased the expression of pro-survival factor survivin. Conclusion: Various concentrations (0.06-0.6 mM) of trans-FA exert both anti-proliferation and anti-migration effects in the human lung cancer cell line H1299. [ABSTRACT FROM AUTHOR]

Melanoma is the deadliest cancer. We identified 7- hydroxydehydronuciferine (7-HDNF) isolated from the leaves of Nelumbo nucifera Gaertn cv. Rosa-plena to be a bio-active agent that antagonizes melanoma tumor growth in mice xenograft model in vivo. Cell proliferation assay demonstrated strong anticancer effects of 7-HDNF to exhibit a dose-dependent behaviour and displayed minor cytotoxicities on normal human skin cells, including epidermal keratinocytes and melanocytes, and dermal fibroblasts. With acridine orange (AO) staining and flow analysis, we found 7-HDNF induced the formation of intracellular vacuoles and the augmentation of acidic vesicular organelles (AVO). The apoptotic cell death ratio was measured via two-dimensional flow cytometry by annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) double stained to confirm the cellular membrane asymmetry lost. One-dimensional flow cytometric analysis showed 7-HDNF increased the cellular arrest in cell cycle at the G2/M phase. Through Western blot examinations, protein expressions were discovered to verify autophagy and apoptosis response mechanisms sharing the associated pathways. Finally, 7-HDNF presented a high-quality antimigratory activity in wound-healing assay. Overall, 7-HDNF presented high-quality anticancer bio-functions and inhibited melanoma tumor growth in vivo and in vitro. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: Human cell-free circulating DNA (cf-DNA) derived mainly from cell apoptosis and necrosis can be measured by a variety of laboratory techniques, but almost all of these methods require sample preparation. We have developed a branched DNA (bDNA)-based Alu assay for quantifying cf-DNA in myocardial infarction (MI) patients. Design and methods: A total of 82 individuals were included in the study; 22 MI and 60 normal controls. cf-DNA was quantified using a bDNA-based Alu assay. Results: cf-DNA was higher in serum compared to plasma and there was a difference between genders. cf-DNA was significantly higher in MI patients compared to the controls. There was no correlation between cf-DNA and creatine kinase-MB (CK-MB), troponin I (cTnI) or myoglobin (MYO). In serial specimens, cf-DNA was sensitive and peaked earlier than cTnI. Conclusions: The bDNA-based Alu assay is a novel method for quantifying human cf-DNA. Increased cf-DNA in MI patients might complement cTnI, CK-MB and MYO in a multiple marker format. [Copyright &y& Elsevier]

Ceramide is a sphingolipid which regulates a variety of signaling pathways in eukaryotic cells. Exogenous ceramide has been shown to induce cellular apoptosis. In this study, we observed that exogenous ceramide induced two distinct morphologies of cell fate following C2-ceramide treatment between the two breast cancer cell lines MCF-7 (wild type p53) and MDA-MB-231 (mutant p53) cells. The growth assessment showed that C2-ceramide caused significant growth inhibition and apoptosis in MDA-MB-231 cells through down-regulating the expression of mutant p53 whereas up-regulating the expression of pro-apoptotic Bad, and the proteolytic activation of caspase-3. However, senescence-associated (SA)-β-galactosidase (β-gal) was regulated in MCF-7 cells after C2-ceramide treatment. The results of proliferation and apoptosis assays showed that MCF-7 cells were more resistant to C2-ceramide treatment compared to MDA-MB-231 cells. Furthermore, C2-ceramide treatment induced a time-responsive increase in Rb protein, a key regulator of senescence accompanied with the upregulation of both mRNA level and protein level of SA-genes PAI-1 and TGaseII in MCF-7 but not in MDA-MB-231 cells, suggesting that some cancer cells escape apoptosis through modulating senescence-like phenotype. The results of our present study depicted the mechanism of C2-ceramide-resistant breast cancer cells, which might benefit the strategic development of ceramide-based chemotherapeutics against cancer in the future. [ABSTRACT FROM AUTHOR]