MLH1-deficient HCT116 colon tumor cells exhibit resistance to the cytostatic and cytotoxic effect of the poly(A) polymerase inhibitor cordycepin (3'-deoxyadenosine) in vitro

Cordycepin (3'-deoxyadenosine) is an inhibitor of poly(A) polymerase (PAP), an enzyme crucial to mRNA 3'-end processing, which produces the shortening of poly(A) tails, leading to the destabilization of mRNAs. Cordycepin inhibits proliferation and induces apoptosis in tumor cells, indicating its antitumor activity. Defective 3'-end processing is associated with hypersensitivity to UV treatment. We investigated the effects of cordycepin on proliferation and apoptosis in MLH1-deficient and MLH1-proficient HCT116 colon tumor cells. MLH1 is a DNA mismatch repair (MMR) protein involved in the processing of damaged DNA. Cells with defective MMR show resistance to certain anticancer drugs. The results showed that MLH1-deficient HCT116 cells are 2-fold less sensitive to the cytostatic effect of cordycepin, as compared to MLH1-proficient cells. This reduced sensitivity to cordycepin in MLH1-deficient cells was associated with reduced upregulation of the cell cycle inhibitor p21. MLH1-deficient cells also exhibited reduced susceptibility to apoptosis upon treatment with cordycepin, as demonstrated by the reduced PARP-1 cleavage. Our findings showed that MLH1-deficient HCT116 colon tumor cells are resistant to the cytostatic and cytotoxic effect of cordycepin, indicating a possible involvement of MMR in mRNA polyadenylation. The findings also suggest that cordycepin is not suitable to therapeutically encounter tumor cells lacking MLH1 expression

Glucosylceramide synthase inhibitors differentially affect expression of glycosphingolipids

Glucosylceramide synthase (GCS) catalyzes the first committed step in the biosynthesis of glucosylceramide (GlcCer)-related glycosphingolipids (GSLs). Although inhibitors of GCS, PPMP and PDMP have been widely used to elucidate their biological function and relevance, our comprehensive literature review revealed that the available data are ambiguous. We therefore investigated whether and to what extent GCS inhibitors affect the expression of lactosylceramide (LacCer), neolacto (nLc4 and P1), ganglio (GM1 and GD3) and globo (Gb3 and SSEA3) series GSLs in a panel of human cancer cell lines using flow cytometry, a commonly applied method investigating cell-surface GSLs after GCS inhibition. Their cell-surface GSL expression considerably varied among cell lines and more importantly, sublethal concentrations (IC10) of both inhibitors preferentially and significantly reduced the expression of Gb3 in the cancer cell lines IGROV1, BG1, HT29 and T47D, whereas SSEA3 was only reduced in BG1. Unexpectedly, the neolacto and ganglio series was not affected. LacCer, the precursor of all GlcCer-related GSL, was significantly reduced only in BG1 cells treated with PPMP. Future research questions addressing particular GSLs require careful consideration; our results indicate that the extent to which there is a decrease in the expression of one or more particular GSLs is dependent on the cell line under investigation, the type of GCS inhibitor and exposure duratio

MyCTC chip: microfluidic-based drug screen with patient-derived tumour cells from liquid biopsies

Cancer patients with advanced disease are characterized by intrinsic challenges in predicting drug response patterns, often leading to ineffective treatment. Current clinical practice for treatment decision-making is commonly based on primary or secondary tumour biopsies, yet when disease progression accelerates, tissue biopsies are not performed on a regular basis. It is in this context that liquid biopsies may offer a unique window to uncover key vulnerabilities, providing valuable information about previously underappreciated treatment opportunities. Here, we present MyCTC chip, a novel microfluidic device enabling the isolation, culture and drug susceptibility testing of cancer cells derived from liquid biopsies. Cancer cell capture is achieved through a label-free, antigen-agnostic enrichment method, and it is followed by cultivation in dedicated conditions, allowing on-chip expansion of captured cells. Upon growth, cancer cells are then transferred to drug screen chambers located within the same device, where multiple compounds can be tested simultaneously. We demonstrate MyCTC chip performance by means of spike-in experiments with patient-derived breast circulating tumour cells, enabling >95% capture rates, as well as prospective processing of blood from breast cancer patients and ascites fluid from patients with ovarian, tubal and endometrial cancer, where sensitivity to specific chemotherapeutic agents was identified. Together, we provide evidence that MyCTC chip may be used to identify personalized drug response patterns in patients with advanced metastatic disease and with limited treatment opportunities

Expression pattern of class I histone deacetylases in vulvar intraepithelial neoplasia and vulvar cancer: a tissue microarray study

BACKGROUND: Epigenetic regulation is an important mechanism leading to cancer initiation and promotion. Histone acetylation by histone deacetylases (HDACs) represents an important part of it. The development of HDAC inhibitors has identified the utility of HDACs as a therapeutic target. Little is known about the epigenetic regulation of vulvar intraepithelial neoplasia (VIN) and vulvar squamous cell cancer (VSCC). In this study, the expression of class I HDACs (HDAC 1, 2 and 3) was compared in a series of VIN and VSCC tissues. METHODS: A tissue micro array (TMA) with specimens from 106 patients with high-grade VIN and 59 patients with vulvar cancer was constructed. The expression of HDACs 1, 2 and 3 were analyzed with immunohistochemistry (IHC). The nuclear expression pattern was evaluated in terms of intensity and percentage of stained nuclei and was compared between vulvar preinvasive lesions and vulvar cancer. RESULTS: HDAC 2 expression was significantly higher in VIN than in VSCC (p < 0.001, Fisher's test). Also, 88.7% (n=94/106) of VIN samples and only 54.5% (n=31/57) of VSCC samples were scored at the maximum level. Conversely, HDAC 3 expression was significantly higher in VSCC (93%, 53/57) compared to VIN (73.6%, 78/106, p=0.003), whereas only a small difference in the expression of HDAC 1 was found between these two entities of vulvar neoplasia. CONCLUSIONS: These results suggest that epigenetic regulation plays a considerable role in the transformation of VIN to invasive vulvar neoplasia

PEGylation of microbead surfaces reduces unspecific antibody binding in glycan-based suspension array

Glycan-based suspension array (SGA) is an "in-house" developed multi-target immunoassay, employing commercially available fluorescent microbeads as a solid support for unique chemically synthesized glycopolymers which capture naturally occurring human anti-glycan antibodies. SGA is a sensitive and reliable tool for the high-throughput screening of anti-glycan antibody alterations characteristic for a vast number of human diseases including cancer. However, unspecific background binding, for instance binding of non-target antibodies, is a common obstacle in such immunoassays. In an attempt to reduce unspecific background binding of serum (or plasma) antibodies, we prepared glycosylated microbeads modified with linear poly(ethylene glycols) (PEGs) of different lengths. We compared several kinds of PEG modifications: (a) partial side-chain substitution of glycopolymers by PEGs of different lengths, (b) end-point addition of biotin-linked PEGs to glycopolymer-coupled beads, and (c) linking of heterobifunctional PEGs to the bead surface prior to glycopolymer immobilization. Among the various modifications investigated, the direct modification of the bead surface with linear heterobifunctional PEGs, consisting of 23- and 60PEG-units significantly reduced the background binding. The end-point addition of biotin-linked PEGs, especially in the case of PEG consisting from 50PEG-units, helped to repel non-target binding caused by endogenous biotin. We observed unspecific binding predominantly for antibodies of IgG but of IgM class. The novel design of fluorescent microbeads allows the detection of human anti-glycan antibodies with increased specificity and opens new horizons for practical application of SGA as a diagnostic tool

Hypericin and 5-aminolevulinic acid-induced protoporphyrin IX induce enhanced phototoxicity in human endometrial cancer cells with non-coherent white light

BACKGROUND: The in vitro experiments described in this study were aimed at exploring a synergistic effect between 5-aminolevulinic acid (5-ALA) induced protoporphyrin IX (PpIX) and hypericin. In a previous study, enhanced phototoxicity was observed in a patient during a clinical study on 5-ALA-based photodynamic tumor localization of breast cancer. This patient ingested a hypericin containing plant extract in parallel to orally applied 5-ALA. METHODS: Human endometrial cancer cells (HEC-1A) were treated with 0.5mM of 5-ALA and 60 nM of hypericin, either separately or combined. Colony formation was assessed after illumination of the cells with both red (635 nm) and white light (400-800 nm) at a dose of 2.5 J/cm(2). Porphyrin metabolites were quantified by HPLC in cells treated with photosensitizers without subsequent illumination. RESULTS: After white light illumination, cells treated with a combination of 5-ALA and hypericin had a significant reduction in colony formation compared with cells treated with 5-ALA only. No significantly enhanced toxicity was found with red light and the 5-ALA plus hypericin combination. In addition, cells treated with both 5-ALA and hypericin tended to produce more PpIX than cells treated with 5-ALA only. CONCLUSIONS: This study demonstrated that treatment of endometrial cancer cells with both 5-ALA and hypericin followed by illumination with white light induced a significantly higher phototoxicity as revealed by colony formation. This setting which generated an in vitro effect similar to the patient's situation, might be applied in the future as an affordable and effective photodynamic therapy (PDT) modality

Conjugates of cytochrome c and antennapedia peptide activate apoptosis and inhibit proliferation of HeLa cancer cells

Polycationic cell-penetrating peptides (CPPs) deliver macromolecules into cells without losing the functional properties of the cargoed macromolecule. The aim of this study was to determine whether exogenous cytochrome c is delivered to HeLa cervical carcinoma cells by the CPP antennapedia (Antp) and activates apoptosis. HeLa cervical carcinoma cells were treated with conjugated Antp-SMCC-cytochrome c (cytochrome c chemically conjugated to Antp) or with non-conjugated Antp and cytochrome c. Sensitivity to the treatments was determined by the clonogenic assay (proliferation) and by immunoblot analysis (apoptosis activation). We report that conjugated Antp-SMCC-cytochrome c activated apoptosis in HeLa cells as demonstrated by poly (ADP-ribose) polymerase 1 (PARP-1) cleavage and inhibited their proliferation. The Antp-SMCC-cytochrome c-induced apoptosis was inhibited by z-VAD-fmk, a pan-caspase inhibitor peptide. Unconjugated Antp or cytochrome c demonstrated no inhibitory effect on survival and proliferation. Our results suggest that chemical coupling of cytochrome c to CPPs may present a possible strategy for delivering cytochrome c into cells and for activating apoptosis

ABO blood groups as a prognostic factor for recurrence in ovarian and vulvar cancer.

The relationship between ABO blood groups (BG) and risk of incidence in cancers including gynecological cancers has been widely studied, showing increased incidence risk for BG A patients. As available data are inconsistent we investigated whether BG and their anti-glycan antibodies (anti-A and anti-B) have prognostic values in gynecological cancers. We retrospectively evaluated 974 patients with gynecological cancers in three cancer centers (Switzerland and Australia) between 1974 and 2014 regarding the relationships between clinico-pathological findings and the BG. Time to disease recurrence was significantly influenced by BG in patients with ovarian (n = 282) and vulvar (n = 67) cancer. BG O or B patients showed a significantly increased risk for ovarian cancer relapse compared to A, 59% and 82%, respectively (p = 0.045; HR O vs A = 1.59 (CI 1.01-2.51) and (p = 0.036; HR A vs B = 0.55 (CI 0.32-0.96). Median time to relapse for advanced stage (n = 126) ovarian cancer patients was 18.2 months for BG O and 32.2 for A (p = 0.031; HR O vs A = 2.07 (CI 1.07-4.02)). BG also significantly influenced relapse-free survival in patients with vulvar cancer (p = 0.002), with BG O tending to have increased relapse risk compared to A (p = 0.089). Blood groups hence associate with recurrence in ovarian and vulvar cancer: women with BG O seem to have a lower ovarian cancer incidence, however are more likely to relapse earlier. The significance of the BG status as a prognostic value is evident and may be helpful to oncologists in prognosticating disease outcome and selecting the appropriate therapy

MLH1-deficient HCT116 colon tumor cells exhibit resistance to the cytostatic and cytotoxic effect of the poly(A) polymerase inhibitor cordycepin (3'-deoxyadenosine)in vitro

Cordycepin (3'-deoxyadenosine) is an inhibitor of poly(A) polymerase (PAP), an enzyme crucial to mRNA 3'-end processing, which produces the shortening of poly(A) tails, leading to the destabilization of mRNAs. Cordycepin inhibits proliferation and induces apoptosis in tumor cells, indicating its antitumor activity. Defective 3'-end processing is associated with hypersensitivity to UV treatment. We investigated the effects of cordycepin on proliferation and apoptosis in MLH1‑deficient and MLH1-proficient HCT116 colon tumor cells. MLH1 is a DNA mismatch repair (MMR) protein involved in the processing of damaged DNA. Cells with defective MMR show resistance to certain anticancer drugs. The results showed that MLH1-deficient HCT116 cells are 2-fold less sensitive to the cytostatic effect of cordycepin, as compared to MLH1-proficient cells. This reduced sensitivity to cordycepin in MLH1-deficient cells was associated with reduced upregulation of the cell cycle inhibitor p21. MLH1-deficient cells also exhibited reduced susceptibility to apoptosis upon treatment with cordycepin, as demonstrated by the reduced PARP-1 cleavage. Our findings showed that MLH1-deficient HCT116 colon tumor cells are resistant to the cytostatic and cytotoxic effect of cordycepin, indicating a possible involvement of MMR in mRNA polyadenylation. The findings also suggest that cordycepin is not suitable to therapeutically encounter tumor cells lacking MLH1 expression