Marizomib (Salinosporamide A) Promotes Apoptosis in A375 and G361 Melanoma Cancer Cells.

Malignant melanoma-a tumor originating from melanocytes-is characterized by dynamic growth and frequent metastases in the early stage of development. Current therapy methods are still insufficient, and there is a need to search for new ways of treating this malady. The induction of apoptosis-physiological cell death-by proteasome inhibitors is recognized as an effective method of non-invasive elimination of cancer cells. In our research, we wanted to check the potential of marizomib (MZB, salinosporamide A, NPI-0052)-an irreversible proteasome inhibitor derived from the marine actinomycete Salinispora tropica-to induce apoptosis in A375 and G361 malignant melanoma cells. We determined the cytotoxic activity of marizomib by performing an MTT test. Ethidium bromide and acridine orange staining demonstrated the disruption of membrane integrity in the examined cell lines. We confirmed the proapoptotic activity of marizomib by flow cytometry with the use of an FITC-Annexin V assay. A Western blot analysis presented an increase in the expression of proteins related to endoplasmic reticulum (ER) stress as well as markers of the apoptosis. The gathered findings suggest that marizomib induced the ER stress in the examined melanoma cancer cells and directed them towards the apoptosis pathway.

The Synergistic Effect of Reduced Graphene Oxide and Proteasome Inhibitor in the Induction of Apoptosis through Oxidative Stress in Breast Cancer Cell Lines.

Reduced graphene oxide (rGO) and a proteasome inhibitor (MG-132) are some of the most commonly used compounds in various biomedical applications. However, the mechanisms of rGO- and MG-132-induced cytotoxicity remain unclear. The aim of this study was to investigate the anticancer effect of rGO and MG-132 against ZR-75-1 and MDA-MB-231 breast cancer cell lines. The results demonstrated that rGO, MG-132 or a mix (rGO + MG-132) induced time- and dose-dependent cytotoxicity in ZR-75-1 and MDA-MB-231 cells. Apart from that, we found that treatment with rGO and MG-132 or the mix increased apoptosis, necrosis and induction of caspase-8 and caspase-9 activity in both breast cancer cell lines. Apoptosis and caspase activation were accompanied by changes in the ultrastructure of mitochondria in ZR-75-1 and MDA-MB-231 cells incubated with rGO. Additionally, in the analyzed cells, we observed the induction of oxidative stress, accompanied by increased apoptosis and cell necrosis. In conclusion, oxidative stress induces apoptosis in the tested cells. At the same time, both mitochondrial and receptor apoptosis pathways are activated. These studies provided new information on the molecular mechanisms of apoptosis in the ZR-75-1 and MDA-MB-231 breast cancer cell lines.

The Influence of Mesotrione on Human Colorectal Adenocarcinoma Cells and Possibility of Its Toxicity Mitigation by Cichoric Acid.

Mesotrione, as a widely used herbicide, is present in the environment in detectable amounts, causing serious damage. Here, we aimed to investigate the effect of mesotrione on Caco-2 cells and the possibility of its toxicity mitigation by cichoric acid. Therefore, we analyzed the cytotoxicity of both these compounds and the selected oxidative stress parameters, apoptosis and interaction of both the tested compounds with the cell membrane and their accumulation within the cells. In cytotoxicity studies, the stimulating activity of mesotrione was observed, and simultaneously, the inhibitory effect of cichoric acid was noticed. This effect was related to the results of oxidative stress analysis and apoptosis measurements. The activity level of key enzymes (glutathione peroxidase, catalase and superoxide dismutase) in Caco-2 cells exposed to cichoric acid was higher as compared to that of the control. The treatment with mesotrione did not induce apoptosis in the Caco-2 cells. The penetration of the studied compounds into the Caco-2 cells was measured by using an HPLC methodology, and the results indicate mesotrione's high penetration capacity. The distribution of charge on the surface of the cell membranes changed under the influence of both compounds. Considering the mutual interactions of beneficial and potentially toxic food ingredients, it should be noted that, despite the observed favorable trend, cichoric acid is not able to overcome the toxic and cancer-stimulating effects of this pesticide.

The Effect of Silica Nanoparticles (SiNPs) on Cytotoxicity, Induction of Oxidative Stress and Apoptosis in Breast Cancer Cell Lines.

Breast cancer is one of the most common cancers in women. Silica nanoparticles (SiNPs) belong to the group of often-used nanoparticles in biomedical applications. The mechanisms of the cytotoxicity, apoptosis, and oxidative stress induced by the 5-15 nm SiNPs still remain unclear. The aim of the study was to evaluate the anti-cancer effect and mechanism of action of SiNPs in breast cancer cell lines. The breast cancer MDA-MB-231 and ZR-75-1 cell lines were analyzed using MTT assay, flow cytometry, and spectrophotometric methods. In this paper, we presented findings about the cytotoxicity, apoptosis, and oxidative stress in both breast cancer cell lines. We indicated that 5-15 nm SiNPs induced dose-dependent cytotoxicity in MDA-MB-231 and ZR-75-1 cells. Moreover, we demonstrated that the process of apoptosis in the studied cell lines was associated with a decrease in the mitochondrial membrane potential (ΔΨm) and an increase in the activity of caspase-9 and caspase-3. Based on the obtained results, 5-15 nm SiNPs are able to induce the mitochondrial apoptosis pathway. Analyzed nanoparticles have also been found to cause an increase in selected oxidative stress parameters in both breast cancer cell lines. The presented study provides an explanation of the possible mechanisms of 5-15 nm SiNPs action in breast cancer cells.

Selected Fungicides as Potential EDC Estrogenic Micropollutants in the Environment.

An increasing level of pesticide exposition is being observed as a result of the consumption of large amounts of fruits, vegetables and grain products, which are key components of the vegetarian diet. Fungicides have been classified as endocrine-disrupting compounds, but their mechanisms of action have not yet been clarified. The effect of boscalid (B), cyprodinil (C) and iprodione (I) combined with Tamoxifen (T) and 17ß-estradiol (E2) on cell viability, cell proliferation, reporter gene expression, ROS content, the cell membrane's function, cell morphology and antioxidant enzymes gene expression in MCF-7 and T47D-KBluc cell lines were investigated. The cell lines were chosen due to their response to 17ß -estradiol. The selected fungicides are commonly used in Poland to protect crops against fungi. Our results revealed that the studied fungicides caused significant increases in cell viability and proliferation, and estrogenic activity was present in all studied compounds depending on their concentrations. Oxidative stress activated uncontrolled cancer cell proliferation by inducing ROS production and by inhibiting antioxidant defense. Our findings verify that the studied fungicides could possibly exhibit endocrine-disrupting properties and exposure should be avoided.

The Reduced Graphene Oxide (rGO) Induces Apoptosis, Autophagy and Cell Cycle Arrest in Breast Cancer Cells.

Reduced graphene oxide (rGO) has already been reported as a potential cytostatic agent in various cancers. However, the mechanisms underlying rGO's cytotoxicity are still insufficiently understood. Thus, the aim of the study was to investigate the molecular and cellular effects of rGO in breast cancer. Given this, two cell lines, MDA-MB-231 and ZR-75-1, were analyzed using MTT test, flow cytometry and Western blot assay. Incubation with rGO resulted in a multitude of effects, including the stimulation of autophagy, cell cycle arrest and, finally, the apoptotic death of cancer cells. Notably, rGO had minimal effect on normal human fibroblasts. Apoptosis in cancer cells was accompanied by decreased mitochondrial membrane potential, the deregulated expression of mitochondrial proteins and the activation of caspase 9 and caspase 3, suggesting that rGO predominantly induced apoptosis via intrinsic pathway. The analysis of LC3 protein expression revealed that rGO also caused autophagy in breast cancer cells. Moreover, rGO treatment resulted in cell cycle arrest, which was accompanied by deregulated p21 expression. Altogether, rGO seems to have multidirectional cytostatic and cytotoxic effects in breast cancer cells, making it a promising agent worthy of further investigation.

Senescence of Tumor Cells in Anticancer Therapy-Beneficial and Detrimental Effects.

Cellular senescence process results in stable cell cycle arrest, which prevents cell proliferation. It can be induced by a variety of stimuli including metabolic stress, DNA damage, telomeres shortening, and oncogenes activation. Senescence is generally considered as a process of tumor suppression, both by preventing cancer cells proliferation and inhibiting cancer progression. It can also be a key effector mechanism for many types of anticancer therapies such as chemotherapy and radiotherapy, both directly and through bioactive molecules released by senescent cells that can stimulate an immune response. Senescence is characterized by a senescence-associated secretory phenotype (SASP) that can have both beneficial and detrimental impact on cancer progression. Despite the negatives, attempts are still being made to use senescence to fight cancer, especially when it comes to senolytics. There is a possibility that a combination of prosenescence therapy-which targets tumor cells and causes their senescence-with senotherapy-which targets senescent cells, can be promising in cancer treatment. This review provides information on cellular senescence, its connection with carcinogenesis and therapeutic possibilities linked to this process.

A Preliminary Study of the Effect of Quercetin on Cytotoxicity, Apoptosis, and Stress Responses in Glioblastoma Cell Lines.

A growing body of evidence indicates that dietary polyphenols show protective effects against various cancers. However, little is known yet about their activity in brain tumors. Here we investigated the interaction of dietary flavonoid quercetin (QCT) with the human glioblastoma A172 and LBC3 cell lines. We demonstrated that QCT evoked cytotoxic effect in both tested cell lines. Microscopic observations, Annexin V-FITC/PI staining, and elevated expression and activity of caspase 3/7 showed that QCT caused predominantly apoptotic death of A172 cells. Further analyses confirmed enhanced ROS generation, deregulated expression of SOD1 and SOD2, depletion of ATP levels, and an overexpression of CHOP, suggesting the activation of oxidative stress and ER stress upon QCT exposure. Finally, elevated expression and activity of caspase 9, indicative of a mitochondrial pathway of apoptosis, was detected. Conversely, in LBC3 cells the pro-apoptotic effect was observed only after 24 h incubation with QCT, and a shift towards necrotic cell death was observed after 48 h of treatment. Altogether, our data indicate that exposure to QCT evoked cell death via activation of intrinsic pathway of apoptosis in A172 cells. These findings suggest that QCT is worth further investigation as a potential pharmacological agent in therapy of brain tumors.

The Preliminary Study on the Proapoptotic Effect of Reduced Graphene Oxide in Breast Cancer Cell Lines.

Breast cancer is the most common cancer diagnosed in women, however traditional therapies have several side effects. This has led to an urgent need to explore novel drug approaches to treatment strategies such as graphene-based nanomaterials such as reduced graphene oxide (rGO). It was noticed as a potential drug due to its target selectivity, easy functionalisation, chemisensitisation, and high drug-loading capacity. rGO is widely used in many fields, including biological and biomedical, due to its unique physicochemical properties. However, the possible mechanisms of rGO toxicity remain unclear. In this paper, we present findings on the cytotoxic and antiproliferative effects of rGO and its ability to induce oxidative stress and apoptosis of breast cancer cell lines. We indicate that rGO induced time- and dose-dependent cytotoxicity in MDA-MB-231 and ZR-75-1 cell lines, but not in T-47D, MCF-7, Hs 578T cell lines. In rGO-treated MDA-MB-231 and ZR-75-1 cell lines, we noticed increased induction of apoptosis and necrosis. In addition, rGO has been found to cause oxidative stress, reduce proliferation, and induce structural changes in breast cancer cells. Taken together, these studies provide new insight into the mechanism of oxidative stress and apoptosis in breast cancer cells.

The Pro-Apoptotic Effect of Silica Nanoparticles Depends on Their Size and Dose, as Well as the Type of Glioblastoma Cells.

Despite intensive investigations, nanoparticle-induced cellular damage is an important problem that has not been fully elucidated yet. Here, we report that silica nanoparticles (SiNPs) demonstrated anticancer influence on glioblastoma cells by the induction of apoptosis or necrosis. These effects are highly cell type-specific, as well as dependent on the size and dose of applied nanoparticles. Exposure of LN-18 and LBC3 cells to different sizes of SiNPs-7 nm, 5-15 nm, or 10-20 nm-at dosages, ranging from 12.5 to 1000 µg/mL, for 24 and 48 h reduced the viability of these cells. Treatment of LN-18 and LBC3 cells with 7 nm or 10-20 nm SiNPs at doses ≥50 µg/mL caused a strong induction of apoptosis, which is connected with an increase of intracellular reactive oxygen species (ROS) production. The 5-15 nm SiNPs exhibited distinct behavior comparing to silica nanoparticles of other studied sizes. In contrast to LBC3, in LN-18 cells exposed to 5-15 nm SiNPs we did not observe any effect on apoptosis. These nanoparticles exerted only strong necrosis, which was connected with a reduction in ROS generation. This suggests that SiNPs can trigger different cellular/molecular effects, depending on the exposure conditions, the size and dose of nanoparticles, and cell type of glioblastoma.

Novel Dual PI3K/mTOR Inhibitor, Apitolisib (GDC-0980), Inhibits Growth and Induces Apoptosis in Human Glioblastoma Cells.

Deregulated PI3K/AKT/mTOR signalling commonly exists in glioblastoma, making this axis an attractive target for therapeutic manipulation. Given that activation of PI3K/AKT/mTOR promotes tumour growth, metastasis, and resistance to anticancer therapies, mTOR inhibitors show promise in the treatment of cancer. The aim of this study was to investigate the underlying mechanism of novel dual PI3K/mTOR inhibitor, Apitolisib (GDC-0980), in A-172 and U-118-MG GBM tumour cell line suppression. It has been demonstrated that GDC-0980 induces time- and dose-dependent cytotoxicity and apoptosis in investigated glioma cell lines. In our study, the strongest induction of apoptosis was exhibited in the A-172 line after 48 h of incubation with 20 µM GDC-0980, where we observed 46.47% of apoptotic cells. In conclusion, we first discovered that dual PI3K/mTOR blockade by GDC-0980 markedly suppressed survival of human GBM cells and induced apoptosis, independent of the ER stress-mediated DR5 activation. We suggest that GDC-0980, by exerting an inhibitory effect on PERK expression, may thus block its inhibitory effect on protein synthesis, leading to intensification of translation, and this may result in an increase in apoptosis. On the other hand, CHOP stimulates protein synthesis and increases apoptosis. These findings suggest that GDC-0980 may be a candidate for further evaluation as a chemotherapeutic agent for anti-GBM therapy.

Molecular and Cellular Effects of Chemical Chaperone-TUDCA on ER-Stressed NHAC-kn Human Articular Chondrocytes Cultured in Normoxic and Hypoxic Conditions.

Osteoarthritis (OA) is considered one of the most common arthritic diseases characterized by progressive degradation and abnormal remodeling of articular cartilage. Potential therapeutics for OA aim at restoring proper chondrocyte functioning and inhibiting apoptosis. Previous studies have demonstrated that tauroursodeoxycholic acid (TUDCA) showed anti-inflammatory and anti-apoptotic activity in many models of various diseases, acting mainly via alleviation of endoplasmic reticulum (ER) stress. However, little is known about cytoprotective effects of TUDCA on chondrocyte cells. The present study was designed to evaluate potential effects of TUDCA on interleukin-1ß (IL-1ß) and tunicamycin (TNC)-stimulated NHAC-kn chondrocytes cultured in normoxic and hypoxic conditions. Our results showed that TUDCA alleviated ER stress in TNC-treated chondrocytes, as demonstrated by reduced CHOP expression; however, it was not effective enough to prevent apoptosis of NHAC-kn cells in either normoxia nor hypoxia. However, co-treatment with TUDCA alleviated inflammatory response induced by IL-1ß, as shown by down regulation of Il-1ß, Il-6, Il-8 and Cox2, and increased the expression of antioxidant enzyme Sod2. Additionally, TUDCA enhanced Col IIα expression in IL-1ß- and TNC-stimulated cells, but only in normoxic conditions. Altogether, these results suggest that although TUDCA may display chondoprotective potential in ER-stressed cells, further analyses are still necessary to fully confirm its possible recommendation as potential candidate in OA therapy.

The cellular effects of novel triazine nitrogen mustards in glioblastoma LBC3, LN-18 and LN-229 cell lines.

1,3,5-triazine is an important heterocyclic skeleton for mono, two or three 2-chloroethylamine groups. The study presented here provides novel information on cellular effects of 1,3,5-triazine with mono, two or three 2-chloroethylamine groups in glioblastoma LBC3, LN-18 and LN-229 cell lines. In our study, the most cytotoxic effect was observed in 1,3,5-triazine with three 2-chloroethylamine groups (12f compound). It has been demonstrated that 12f induce time- and dose-dependent cytotoxicity in all investigated glioma cell lines. Apart from that in glioblastoma cells, treated with 12f compound, we noticed strong induction of apoptosis. In conclusion, this research provides novel information concerning cellular effects of apoptosis in LBC3, LN-18 and LN-229 cell lines. Moreover, we suggest that 12f compound may be a candidate for further evaluation as an effective chemotherapeutic agent for human glioblastoma cells.

The modulating effect of lipid bilayer/p-coumaric acid interactions on electrical properties of model lipid membranes and human glioblastoma cells.

Biological membranes are one of the most important elements of living cells determining their permeability to the active compounds. Still, little is known about the drug-membrane interactions in terms of pharmacological properties of potential drugs. Chemoprevention based on natural compounds is becoming a strong trend in modern oncopharmacology, and p-coumaric acid (p-CoA) is one such compound with tentative anticancer activity. The microelectrophoretic mobility measurements and electrochemical impedance spectroscopy were applied to study the effects of p-CoA on electrical properties of liposomes, spherical bilayers, and human glioblastoma cell membranes. Our results demonstrated that after treatment with p-CoA, the surface charge of LBC3, LN-229 and LN-18 cell lines was significantly changed in alkaline pH solutions, but not in acidic pH solutions. In contrast, no changes in surface charge density values were registered for phosphatidylethanolamine liposomal membranes and A172 cell membranes after p-CoA treatment. The impedance data showed an increase in values of both the electrical capacitance and the electrical resistance, indicating that p-CoA can be partially inserted into the phosphatidylcholine bilayers. The MTT assay showed cell line-dependent cytotoxic effect of p-CoA. Further molecular analyses revealed the ATP depletion and gene transcription modulation, which might indicate organelle membrane-crossing potential of p-CoA. These results suggest, that changes in surface charge of membranes of living cells not only might be potential predictor of membrane permeability, but also indicate differential composition of cell membranes in various cell lines. Thus further multidirectional analyses are required to implement electrochemical methods as standard testing procedures during drug development process.

Molecular and cellular effects of a novel hydroxamate-based HDAC inhibitor - belinostat - in glioblastoma cell lines: a preliminary report.

Histone deacetylase (HDAC) inhibitors are now intensively investigated as potential cytostatic agents in many malignancies. Here, we provide novel information concerning the influence of belinostat (Bel), a hydroxamate-based pan-HDAC inhibitor, on glioblastoma LN-229 and LN-18 cells. We found that LN-229 cells stimulated with 2 µmol/L of Bel for 48 h resulted in 70 % apoptosis, while equivalent treatment of LN-18 cells resulted in only 28 % apoptosis. In LN-229 cells this effect was followed by up-regulation of pro-apoptotic genes including Puma, Bim, Chop and p21. In treated LN-18 cells only p21 was markedly overexpressed. Simultaneously, LN-229 cells treated with 2 µmol/L of Bel for 48 h exhibited down-regulation of molecular chaperones GRP78 and GRP94 at the protein level. In contrast, in LN-18 cells Western blot analysis did not show any marked changes in GRP78 nor GRP94 expression. Despite noticeable overexpression of p21, there were no signs of evident G1 nor G2/M cell cycle arrest, however, the reduction in number of the S phase cells was observed in both cell lines. These results collectively suggest that Bel can be considered as potential anti-glioblastoma agent. To our knowledge this is the first report presenting the effects of belinostat treatment in glioblastoma cell lines.

Phenylbutyrate-a pan-HDAC inhibitor-suppresses proliferation of glioblastoma LN-229 cell line.

Phenylbutyrate (PBA) is a histone deacetylase inhibitor known for inducing differentiation, cell cycle arrest, and apoptosis in various cancer cells. However, the effects of PBA seem to be very cell-type-specific and sometimes limited exclusively to a particular cell line. Here, we provided novel information concerning cellular effects of PBA in LN-229 and LN-18 glioblastoma cell lines which have not been previously evaluated in context of PBA exposure. We found that LN-18 cells were PBA-insensitive even at high concentrations of PBA. In contrary, in LN-229 cells, 5 and 15 mmol/L PBA inhibited cell growth and proliferation mainly by causing prominent changes in cell morphology and promoting S- and G2/M-dependent cell cycle arrest. Moreover, we observed nearly a 3-fold increase in apoptosis of LN-229 cells treated with 15 mmol/L PBA, in comparison to control. Furthermore, PBA was found to up-regulate the expression of p21 whereas p53 expression level remained unchanged. We also showed that PBA down-regulated the expression of the anti-apoptotic genes Bcl-2/Bcl-X L , however without affecting the expression of pro-apoptotic Bax and Bim. Taken together, our results suggest that PBA might potentially be considered as an agent slowing-down the progress of glioblastoma; however, further analyses are still needed to comprehensively resolve the nature of its activity in this type of cancer.

Low glucose dependent decrease of apoptosis and induction of autophagy in breast cancer MCF-7 cells.

Cancer cells have developed a number of adaptation mechanisms involving the signal activation of the transduction pathways, which promotes the progression and metastasis. Our results showed that the percentage of apoptotic MCF-7 cells incubated in the low glucose medium for 48 h was lower in comparison to those cultured in the high glucose medium, despite the high expression of the proapoptotic transcription factor-CHOP. Furthermore, the MCF-7 cells incubated in the low glucose medium for 48 h showed a higher expression of NF-κB p100/p52 subunits compared to cells incubated in the high glucose medium. Moreover, our findings demonstrated that the shortage of glucose strongly induces autophagy in MCF-7 cells. The activation of this process is not associated with the changes in the expression of mTOR kinase. We suggest, that the antiapoptotic chaperone ORP150 induction, transcription factor NF-κB2 activation, and increased autophagy constitute mechanisms protecting the MCF-7 cells against apoptosis.

Efficient apoptosis and necrosis induction by proteasome inhibitor: bortezomib in the DLD-1 human colon cancer cell line.

The inhibition of the 26S proteasome evokes endoplasmic reticulum stress, which has been shown to be implicated in the antitumoral effects of proteasome inhibitors. The cellular and molecular effects of the proteasome inhibitor-bortezomib-on human colon cancer cells are as yet poorly characterized. Bortezomib selectively induces apoptosis in some cancer cells. However, the nature of its selectivity remains unknown. Previously, we demonstrated that, in contrast to normal fibroblasts, bortezomib treatment evoked strong effect on apoptosis of breast cancer cells incubated in hypoxic and normoxic conditions. The study presented here provides novel information on the cellular effects of bortezomib in DLD-1 colon cancer cells line. We observe twofold higher percentage of apoptotic cells incubated for 48 h with 25 and 50 nmol/l of bortezomib in hypoxic conditions and four-, fivefold increase in normoxic conditions in comparison to control cells, incubated without bortezomib. It is of interest that bortezomib evokes strong effect on necrosis of DLD-1 colon cancer cell line. We observe the sixfold increase in necrosis of DLD-1 cells incubated with 25 or 50 nmol/l of bortezomib for 48 h in hypoxia and fourfold increase in normoxic conditions in comparison to adequate controls. We suggest that bortezomib may be candidates for further evaluation as chemotherapeutic agents for human colon cancer.

Increased expression of MUC1 and sialyl Lewis antigens in different areas of clear renal cell carcinoma.

BACKGROUND: Changes in expression patterns of the sialyl Lewis antigens and MUC1 mucin can be considered as markers for the diagnosis of various cancers. However, there are no reports which have been devoted to analysis of differences in the sialyl Lewis antigens and MUC1 expression patterns as potential discrimination markers among different areas of clear cell renal cell carcinoma (ccRCC). The aim of this study was to determine the level of MUC1 and specific Lewis antigens on glycoproteins in three different areas: tumor (cancer tissue), intermediate zone (adjacent to tumor tissue) and normal renal cortex/medulla (uninvolved by tumor). METHODS: Study was performed on renal tissues taken from 30 patients with clear cell renal cell carcinoma. Relative amounts of sugar structures bound with proteins were determined by ELISA-like test with biotinylated lectins or monoclonal antibodies: anti-MUC1 and anti-sialyl Lewis(a/x). The study presented here provides novel information about relationship between MUC1 and sialyl Lewis antigens in the tumor, intermediate zone and noninvolved areas of normal renal tissue distant of tumor. RESULTS: We have found statistically significant increase of MUC1 and sialic acid linked by α-2,3 bond with galactose in cancer tissue and in intermediate zone comparing to normal renal tissue distant of tumor. Moreover, we observed statistically significant increase of sialic acid linked by α-2,6 bond with Gal/GalNAc and sialyl Lewis(a/x) antigens in cancer tissues only, comparing to normal ones. CONCLUSIONS: MUC1 and sialylated antigens can be involved in renal tumor development and can be considered as potential markers distinguishing normal renal tissue from intermediate zone and from cancer renal cells during ccRCC development.