Cholangiocarcinoma is a disease with a poor prognosis and increasing incidence and hence there is a pressing unmet clinical need for new adjuvant treatments. Protein kinase CK2 (previously casein kinase II) is a ubiquitously expressed protein kinase that is up-regulated in multiple cancer cell types. The inhibition of CK2 activity using CX-4945 (Silmitasertib) has been proposed as a novel treatment in multiple disease settings including cholangiocarcinoma. Here, we show that CX-4945 inhibited the proliferation of cholangiocarcinoma cell lines in vitro. Moreover, CX-4945 treatment induced the formation of cytosolic vacuoles in cholangiocarcinoma cell lines and other cancer cell lines. The vacuoles contained extracellular fluid and had neutral pH, features characteristic of methuosis. In contrast, simultaneous knockdown of both the α and α′ catalytic subunits of protein kinase CK2 using small interfering RNA (siRNA) had little or no effect on the proliferation of cholangiocarcinoma cell lines and failed to induce the vacuole formation. Surprisingly, low doses of CX-4945 increased the invasive properties of cholangiocarcinoma cells due to an upregulation of matrix metallopeptidase 7 (MMP-7), while the knockdown of CK2 inhibited cell invasion. Our data suggest that CX-4945 inhibits cell proliferation and induces cell death via CK2-independent pathways. Moreover, the increase in cell invasion brought about by CX-4945 treatment suggests that this drug might increase tumor invasion in clinical settings.

The association between iron overload and osteoporosis has been found in many diseases, such as hemochromatosis, β-thalassemia and sickle cell anemia with multiple blood transfusion. One of the contributing factors is iron toxicity to osteoblasts. Some studies showed the negative effects of iron on osteoblasts; however, the effects of two biological available iron species, i.e., ferric and ferrous, on osteoblasts are elusive. Since most intracellular ionized iron is ferric, osteoblasts was hypothesized to be more responsive to ferric iron. Herein, ferric ammonium citrate (FAC) and ferrous ammonium sulfate (FAS) were used as ferric and ferrous donors. Our results showed that both iron species suppressed cell survival and proliferation. Both also induced osteoblast cell death consistent with the higher levels of cleaved caspase 3 and caspase 7 in osteoblasts, indicating that iron induced osteoblast apoptosis. Iron treatments led to the elevated intracellular iron in osteoblasts as determined by atomic absorption spectrophotometry, thereby leading to a decreased expression of genes for cellular iron import and increased expression of genes for cellular iron export. Effects of FAC and FAS on osteoblast differentiation were determined by the activity of alkaline phosphatase (ALP). The lower ALP activity from osteoblast with iron exposure was found. In addition, ferric and ferrous differentially induced osteoblastic and osteoblast-derived osteoclastogenic gene expression alterations in osteoblast. Even though both iron species had similar effects on osteoblast cell survival and differentiation, the overall effects were markedly stronger in FAC-treated groups, suggesting that osteoblasts were more sensitive to ferric than ferrous.

Extracellular nucleotides were first proposed as signaling molecules in 1972 (1). Signaling through purinergic receptors is ubiquitous due to the diversity of purine and pyrimidine ligands, the number of receptors and extracellular nucleotidases. Purinergic signaling has been shown to play a role in many pathways including neurotransmission (2), cell differentiation, hormone secretion, vasodilation, cell proliferation, wound healing and apoptosis (3). There are two distinct families of purinergic receptors: P1 receptors for adenosine and P2 receptors for ATP/ADP and UTP/UDP ligands. P2 receptors are further divided into ligand-gated ion channel receptors, P2X, and G protein-coupled receptor, P2Y, subfamilies. To date, four P1 receptors (A 1,2a,2b,3 ), seven P2X receptors (P2X 1-7 ) and eight P2Y receptors (P2Y 1,2,4,6,11-14 ) have been identified in mammalian cells (4). The adenosine receptor subtypes A 1 and A 3 downregulate the production of cAMP, while A 2a and A 2b subtypes up-regulate the production of cAMP. Activation of P2X receptors leads to an influx of cations from the extracellular space, while activation of P2Y receptors leads to either an elevation of intracellular Ca 2+ from endoplasmic reticulum stores or down-regulation of cAMP production depending on the specific subtype of P2Y receptor activated.Growth suppression by the P2 agonist, ATP, was demonstrated first by Rapaport in 1983 (5). Exogenous ATP was shown to suppress the growth of pancreatic and colon cancer by causing cell-cycle arrest in S-phase. To date, the anticancer activity of extracellular nucleotides has been investigated in many types of cancer, including leukemia, melanoma and non-melanoma skin cancer, colorectal cancer, lung cancer, cervical cancer, prostate cancer (PCa) and squamous cell skin cancer (6). These led to clinical trials in patients with colorectal and non-small cell lung cancer that showed promising results with limited side-effects (7-9).PCa is the most frequently diagnosed cancer in North American men and the second leading cause of cancerrelated death in American men. It was estimated that there would be approximately 180,890 new cases of PCa and 26,5120 related deaths in the United States alone in 2016 (10). Current standard treatments for advanced PCa include various hormonal therapies whose goal is the ablation of androgens and their action (11). Even though 70% to 80% of patients respond well to first-line treatment, most patients eventually develop castrate-resistant disease (CRPCa) (12). Novel therapy therefore is needed to eliminate both early and 529 Τhis article is freely accessible online.

A runaway PRH/HHEX-Notch3 positive feedback loop drives cholangiocarcinoma and determines response to CDK4/6 inhibition.

ATP and adenosine had anti-proliferative and anti-motility effects in CCA cells, while there was a smaller effect on normal cholangiocytes. These data indicate the potential use of ATP and odenosine as a novel therapy for CCA.

Cholangiocarcinoma (CCA) is a lethal disease with increasing incidence worldwide. Previous study showed that CCA was sensitive to adenosine. Thereby, molecular mechanisms of CCA inhibition by adenosine were examined in this study. Our results showed that adenosine inhibited CCA cells via an uptake of adenosine through equilibrative nucleoside transporters (ENTs), instead of activation of adenosine receptors. The inhibition of ENTs by NBTI caused the inhibitory effect of adenosine to subside, while adenosine receptor antagonists, caffeine and CGS-15943, failed to do so. Intracellular adenosine level was increased after adenosine treatment. Also, a conversion of adenosine to AMP by adenosine kinase is required in this inhibition. On the other hand, inosine, which is a metabolic product of adenosine has very little inhibitory effect on CCA cells. This indicates that a conversion of adenosine to inosine may reduce adenosine inhibitory effect. Furthermore, there was no specific correlation between level of proinflammatory proteins and CCA responses to adenosine. A metabolic stable analog of adenosine, 2Cl-adenosine, exerted higher inhibition on CCA cell growth. The disturbance in intracellular AMP level also led to an activation of 5′ AMP-activated protein kinase (AMPK). Accordingly, we proposed a novel adenosine-mediated cancer cell growth and invasion suppression via a receptor-independent mechanism in CCA.

Background: The incidence of cholangiocarcinoma (CCA) is increasing worldwide and current single chemotherapeutic drug treatments are ineffective. CX-4945 and cisplatin are currently in clinical trial for CCA treatment. Materials and Methods: We assessed the effects of the sequence of administration of CX-4945 and cisplatin applied in combination treatments on their efficacy in CCA cells in vitro. CCA cell viability was examined using 3-( 4,5dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Apoptosis was examined using flow cytometry. The percentage of cells positive for phosphorylated H2A histone family member X (γ-H2AX) were measured using both flow cytometry and immunofluorescence. Results: CCA cell viability was reduced to 50% after 24 h of treatments with CX-4945 and cisplatin as single agents. Interestingly, treatment with cisplatin 6 h prior to CX-4945 treatment induced significantly more DNA damage and apoptosis than CX-4945 treatment followed by cisplatin. Unexpectedly, CX-4945 treatment followed by cisplatin was less effective than single treatment in RMCCA-1 CCA cells. In addition, a 1:1 ratio of each drug was the most effective combination in these cells. Conclusion: These data demonstrate that the combination of CX-4945 and cis platin acts additively when cisplatin is applied first, at least in part due to increased DNA damage and apoptosis. Furthermore, treatment with CX-4945 prior to cisplatin treatment reduces the efficacy of this drug combination in CCA cells.

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