Induced Cancer Cell Proliferation Research Articles

Non-enzymatic glycation of protein induces cancer cell proliferation and its inhibition by quercetin: Spectroscopic, cytotoxicity and molecular docking studies

Methylglyoxal (MG) is a potent glycating agent which reacts with proteins to form advanced glycation end products (AGEs). These chemically stable AGEs crosslink with proteins and could lead to amyloid formation that has the role in several diseases including Alzheimer’s and Parkinson’s. In this piece of work, glycation-induced conformational changes in HSA were observed with quenching of tryptophan fluorescence by 73.8% (41 nm red shift) and loss of hydrophobicity of HSA. CD spectroscopy result reaffirmed secondary structure changes in HSA. Moreover, MG-induced changes in HSA, proceeds to amyloid structure as characterized by an increase in thioflavin (ThT) fluorescence and transmission electron microscopy (TEM) images of HSA aggregates. Quercetin was found to inhibit both AGEs production and amyloid formation. Viability of MCF-7 cells was found to be increased with AGEs treatment, illustrating proliferation of cancer cells. Wound healing assay also revealed increased proliferation and migration of cells in the presence of AGEs. Additionally, molecular docking analyses were performed to demonstrate interactions involved in the stabilization of HSA-quercetin complex. The binding affinities of quercetin were found to be (K d = 105 M −1) much higher compared with MG (K d = 102 M −1). From this study, it is quite clear that quercetin reverses the effect of MG by sterically inhibiting the interaction between HSA and MG. Communicated by Ramaswamy H. Sarma

PADI3 plays an antitumor role via the Hsp90/CKS1 pathway in colon cancer

BackgroundCKS1 is highly expressed in colon cancer tissues, and is essential for cancer cell proliferation. The downstream molecular mechanism of CKS1 has been fully studied, but the upstream regulatory mechanism of it is still unclear. Earlier research found that PADI3 plays its anti-tumor roles via suppress cell proliferation, in this study, we found that the expression pattern of PADI3 and CKS1 are negatively correlated in colon cancer tissues, and overexpression of PADI3 can partly reverse CKS1 induced cancer cell proliferation. However, the regulatory mechanism of PADI3 and CKS1 in the tumorigenesis of colon cancer is still unclear and need to do further research.MethodsWestern blot and real-time PCR were used to detect the expression levels of genes. CCK-8 and colony formation assays were used to examine cell proliferation and colony formation ability. Overexpression and rescue experiments were used to study the molecular mechanism of CKS1 in colon cancer cells, BALB/c nude mice were used to study the function of CKS1 in vivo.ResultsCKS1 is highly expressed in colon cancer tissues, and the overexpression of CKS1 promotes cell proliferation and colony formation in both HCT116 (originating from primary colon cancer) and SW620 (originating from metastatic tumor nodules of colon cancer) cells. CKS1-expressing HCT116 cells produced larger tumors than the control cells. The expression pattern of PADI3 and CKS1 are negatively correlation in clinical samples of colon cancer, further study indicates that PADI3 can significantly decrease Hsp90 and CKS1 expression, and Hsp90 is essential for PADI3 to downregulate CKS1expression in colon cancer cells.ConclusionsPADI3 exerts its antitumor activity by inhibiting Hsp90 and CKS1 expression, and Hsp90 is essential for PADI3 to suppress CKS1 expression.

266Loss of pumilio 1 phosphorylation turns off the regulation of miRNA-221 on gene p27kip1 in the heart

Abstract Background MicroRNAs regulate gene expression post-transcriptionally via complementary sequence pairing of mRNA 3'UTR and miRNA seed region. MiR-221 downregulates p27kip1 Cyclin-dependent kinase inhibitor 1B (p27), a cell cycle inhibitor, through direct targeting. The down-regulation of p27 caused by miR-221 upregulation induces cancer cell proliferation and has been reported to be closely associated with human cancer metastasis. This regulation is dependent on the existence of pumilio 1 (PUM1). Meanwhile miR-221 mimics protect cardiac myocytes against ischemic injury. It is a potential therapeutic target for cardioprotection. We investigated whether miR-221 targeted p27 in the heart. Purpose To test the hypothesis that the regulation of miR-221 on p27 is abolished in the heart due to lack of RNA binding protein (RBP) PMU1 phosphorylation but not due to p27 3'UTR shortening. Methods Primary cardiac fibroblasts (cFB) were isolated and cultured under normoxia and hypoxia. After transfections of miR-221 mimics and mimic control (MC), cell proliferation was assessed by cell number, CCk-8 and Ki67 staining. In vivo rats undergoing left coronary artery ligation (MI) and Sham were treated with intravenous miR-221 mimics. Cells or cardiac tissue were collected to measure p27 and PUM1 by RT-qPCR and Western blot (WB). Full length p27 (coding plus 3'UTR sequence) and 3'UTR p27 sequence were quantified using specific primers. The ratio of 3'UTR/Full length was compared to indicate changes between groups. The ratios of 3'UTR/Full length were compared to indicate changes between groups. Results MiR-221 mimics significantly downregulated the expression of p27 mRNA and protein in cFB in both normoxia and hypoxia. P27 downregulation led to cFB proliferation, which could be abrogated by p27 overexpression. miR-221 mimic treatment increased cardiac miR-221 by ∼2–5 fold in Sham and ∼15 fold in MI. Whilst p27 expression was not affected in either Sham or MI hearts. Simultaneously α-SMA+ cells, an indication of cFB number and activation, were reduced by miR-221 mimic in Sham and MI heart. The ratios of p27 3'UTR/full length did not vary significantly between cultured cFB and heart (Sham and MI), indicating the 3'UTR length did not vary between cFB and the whole heart. PUM1 mRNA expression was stable in cFB and the heart. However, phosphorylated PUM1 was highly expressed in cFB but completely diminished in Sham and MI hearts. Conclusion MiR-221 downregulated p27 in primary cFB and induced cell proliferation in vitro. miR-221 could not regulate cardiac p27 expression nor increase cFB proliferation in vivo. MiR-221 induced p27 regulation was correlated with the presence or absence of phosphorylated PUM1. For the first time, we demonstrated that loss of phosphorylated PUM1 turns off the regulation of miRNA-221 on gene p27 in the heart. The mechanism of PUM1 phosphorylation warrant future investigation.

Phenolic Compound Profile and Functionality of Aqueous Overripe Tempe Extracts

Tempe is a soy fermentation product and has been associated with many health benefits. It is usually consumed after 48 hours of fermentation; however extended fermentation is sometimes favoured. Since cooking involves water, it is of interest to study the health benefits of tempe water extract. In this study, we focused our study on total phenols, total flavonoids, DPPH free radical scavenging activity, cytotoxic activity, and identification of the main flavonoids. Our findings demonstrated that concentration of water-soluble flavonoids in tempe increased as fermentation time was prolonged. Fermentation for 60 hr resulted in extracts with very noticeable cytotoxic activity against MCF-7 cancer cell line (IC50 of 8.70 µg/ml). The cytotoxic activity of the extracts was fermentation time-dependent following non-linear relationship. The activity showed strong inverse correlation with total phenols and flavonoids in the extracts. LC-MS/MS data suggested that extracts from control and 24-hr fermented tempe demonstrated the highest responses for genistein, genistin, daidzein, daidzin, and glycitein, compared to those of other treatments and therefore suggested that excessive amount of the isoflavones, particularly genistein, induced cancer cell proliferation but lesser yet optimum concentration (observed at 60 hr-fermentation) contributed to otherwise effect.

Leptin promotes fatty acid oxidation and OXPHOS via the c-Myc/PGC-1 pathway in cancer cells.

Alteration in cellular energy metabolism plays a critical role in the development and progression of cancer. Leptin is a hormone secreted by adipose tissue. Recent reports have shown that leptin can induce cancer cell proliferation and regulate cell energy metabolism, but the regulatory mechanism is still unclear. Here, we showed that leptin could promote cell proliferation and maintain high adenosine triphosphate levels in HCT116 and MCF-7 cells. The expression levels of carnitine palmitoyl transferase 1A (CPT1A), pyruvate dehydrogenase, succinate dehydrogenase subunit A and mitochondrial respiratory chain-associated proteins NADH dehydrogenase 1 (ND1), NADH:ubiquinone oxidoreductase subunit B8, and mitochondrial transcription factor A (TFAM) were distinctly increased in leptin-treated HCT116 and MCF-7 cells, while fatty acid synthase and lactate dehydrogenase expression were downregulated. Simultaneously, we found that c-Myc and peroxisome proliferator-activated receptor gamma co-activator 1 (PGC-1) protein expression levels were significantly increased. These results indicated that leptin boosted fatty acid β-oxidation and the tricarboxylic acid cycle, enhanced oxidative phosphorylation (OXPHOS) activity, and inhibited fatty acid synthesis and glycolysis in tumor cells. Gene transfection experiments revealed that leptin could induce the expression of c-Myc. Moreover, the expressions of PGC-1, CPT1A, and TFAM proteins were downregulated in HCT116 cells with low expression of c-Myc, and the expression levels of these proteins were increased in HCT116 cells overexpressing c-Myc. These findings suggest that leptin plays an important role in the regulation of energy metabolism in tumor cells. It may regulate fatty acid oxidation and OXPHOS of tumor cells by regulating the c-Myc/PGC-1 pathway. Targeting metabolic pathways for cancer treatment has been investigated as potential preventive or therapeutic methods. This study has important implications for the clinical therapy of tumor cell metabolism through hormone regulation.

CRKL regulates alternative splicing of cancer-related genes in cervical cancer samples and HeLa cell

BackgroundAberrant spliced isoforms are specifically associated with cancer progression and metastasis. The cytoplasmic adaptor CRKL (v-crk avian sarcoma virus CT10 oncogene homolog-like) is a CRK like proto-oncogene, which encodes a SH2 and SH3 (src homology) domain-containing adaptor protein. CRKL is tightly linked to leukemia via its binding partners BCR-ABL and TEL-ABL, upregulated in multiple types of human cancers, and induce cancer cell proliferation and invasion. However, it remains unclear whether signaling adaptors such as CRKL could regulate alternative splicing.MethodsWe analyzed the expression level of CRKL in 305 cervical cancer tissue samples available in TCGA database, and then selected two groups of cancer samples with CRKL differentially expressed to analyzed potential CRKL-regulated alternative splicing events (ASEs). CRKL was knocked down by shRNA to further study CRKL-regulated alternative splicing and the activity of SR protein kinases in HeLa cells using RNA-Seq and Western blot techniques. We validated 43 CRKL-regulated ASEs detected by RNA-seq in HeLa cells, using RT-qPCR analysis of HeLa cell samples and using RNA-seq data of the two group of clinical cervical samples.ResultsThe expression of CRKL was mostly up-regulated in stage I cervical cancer samples. Knock-down of CRKL led to a reduced cell proliferation. CRKL-regulated alternative splicing of a large number of genes were enriched in cancer-related functional pathways, among which DNA repair and G2/M mitotic cell cycle, GnRH signaling were shared among the top 10 enriched GO terms and KEGG pathways by results from clinical samples and HeLa cell model. We showed that CRKL-regulated ASEs revealed by computational analysis using ABLas software in HeLa cell were highly validated by RT-qPCR, and also validated by cervical cancer clinical samples.ConclusionsThis is the first report of CRKL-regulation of the alternative splicing of a number of genes critical in tumorigenesis and cancer progression, which is consistent with CRKL reported role as a signaling adaptor and a kinase. Our results underline that the signaling adaptor CRKL might integrate the external and intrinsic cellular signals and coordinate the dynamic activation of cellular signaling pathways including alternative splicing regulation.

Annurca Apple Polyphenols Protect Murine Hair Follicles from Taxane Induced Dystrophy and Hijacks Polyunsaturated Fatty Acid Metabolism toward β-Oxidation.

Chemotherapy-induced alopecia (CIA) is a common side effect of conventional chemotherapy and represents a major problem in clinical oncology. Even months after the end of chemotherapy, many cancer patients complain of hair loss, a condition that is psychologically difficult to manage. CIA disturbs social and sexual interactions and causes anxiety and depression. Synthetic drugs protecting from CIA and endowed with hair growth stimulatory properties are prescribed with caution by oncologists. Hormones, growth factors, morphogens could unwontedly protect tumour cells or induce cancer cell proliferation and are thus considered incompatible with many chemotherapy regimens. Nutraceuticals, on the contrary, have been shown to be safe and effective treatment options for hair loss. We here show that polyphenols from Malus Pumila Miller cv Annurca are endowed with hair growth promoting activity and can be considered a safe alternative to avoid CIA. In vitro, Annurca Apple Polyphenolic Extract (AAE) protects murine Hair Follicles (HF) from taxanes induced dystrophy. Moreover, in virtue of its mechanism of action, AAE is herein proven to be compatible with chemotherapy regimens. AAE forces HFs to produce ATP using mitochondrial β-oxidation, reducing Pentose Phosphate Pathway (PPP) rate and nucleotides production. As consequence, DNA replication and mitosis are not stimulated, while a pool of free amino acids usually involved in catabolic reactions are spared for keratin production. Moreover, measuring the effect exerted on Poly Unsaturated Fatty Acid (PUFA) metabolism, we prove that AAE promotes hair-growth by increasing the intracellular levels of Prostaglandins F2α (PGF2α) and by hijacking PUFA catabolites toward β-oxidation.

Ubiquitylation and degradation of adenomatous polyposis coli by MKRN1 enhances Wnt/β-catenin signaling.

The adenomatous polyposis coli (APC) protein has a tumor-suppressor function by acting as a negative regulator of the Wnt signaling pathway. While its role as a tumor suppressor is well-defined, the post-translational modifications that regulate APC stability are not fully understood. Here we showed that MKRN1, an E3 ligase, could directly interact with and ubiquitylate APC, promoting its proteasomal degradation. In contrast, an E3 ligase-defective MKRN1 mutant was no longer capable of regulating APC, indicating that its E3 ligase activity is required for APC regulation by MKRN1. Strengthening these results, MKRN1 ablation resulted in reduced β-catenin activity and decreased expression of Wnt target genes. The ability of the Wnt-dependent pathway to induce cancer cell proliferation, migration, and invasion was impaired by MKRN1 depletion, but restored by simultaneous APC knockdown. Taken together, these results demonstrate that MKRN1 functions as a novel E3 ligase of APC that positively regulates Wnt/β-catenin-mediated biological processes.

A Kappa Opioid Receptor Agonist Blocks Bone Cancer Pain Without Altering Bone Loss, Tumor Size, or Cancer Cell Proliferation in a Mouse Model of Cancer-Induced Bone Pain

Breast cancer metastasizes to bone, diminishing quality of life of patients because of pain, fracture, and limited mobility. Cancer-induced bone pain (CIBP) is characterized as moderate to severe ongoing pain, primarily managed by mu opioid agonists such as fentanyl. However, opioids are limited by escalating doses and serious side effects. One alternative may be kappa opioid receptor (KOR) agonists. There are few studies examining KOR efficacy on CIBP, whereas KOR agonists are efficacious in peripheral and inflammatory pain. We thus examined the effects of the KOR agonist U50,488 given twice daily across 7 days to block CIBP, tumor-induced bone loss, and tumor burden. U50,488 dose-dependently blocked tumor-induced spontaneous flinching and impaired limb use, without changing tactile hypersensitivity, and was fully reversed by the KOR antagonist nor-binaltorphimine. U50,488 treatment was higher in efficacy and duration of action at later time points. U50,488 blocked this pain without altering tumor-induced bone loss or tumor growth. Follow-up studies in human cancer cell lines confirmed that KOR agonists do not affect cancer cell proliferation. These studies suggest that KOR agonists could be a new target for cancer pain management that does not induce cancer cell proliferation or alter bone loss. PerspectiveThis study demonstrates the efficacy of KOR agonists in the treatment of bone cancer-induced pain in mice, without changing tumor size or proliferation in cancer cell lines. This suggests that KOR agonists could be used to manage cancer pain without the drawbacks of mu opioid agonists and without worsening disease progression.

Abstract B106: Antibody-drug conjugates targeted at human aspartyl (asparaginyl) β-hydroxylase

Abstract Antibody-drug conjugates (ADCs) consist of an antibody that is specific for a disease antigen linked to one or more drug molecules. The goal is to utilize the antibody as a means of specific delivery of the drug to diseased cells. Theoretically this should decrease systemic exposure to the drug and allow for use of a lower dose. In cancer, the approach employs an antibody targeted at a tumor-associated antigen and a cytotoxic or cytostatic drug. To date there have been three ADCs approved by the US FDA for cancer treatment, and many more are now in the development stage. The efficacy of any ADC is dependent on three factors: the antibody, the attached drug, and the linker used to connect them. While each of these factors is of import, with the growth of interest in ADCs for cancer therapy, the use of specific drugs and linkers has become more routine. Thus, the specificities of the antibody and target antigen are now perhaps the primary obstacles towards the development of novel ADCs. Human aspartyl (asparaginyl) β-hydroxylase (HAAH) is an embryonic/developmental protein, which is downregulated in normal cells after birth but overexpressed on the surface of many malignant cells. It has been demonstrated to be sufficient to induce cancer cell proliferation, motility, and invasiveness. The enzyme hydroxylates important residues in the NOTCH protein altering signal transduction pathways that lead to increased growth and metastatic potential. Increased levels of HAAH have been detected by immunohistochemistry in a diverse array of solid and hematologic cancers (n > 20), including liver, bile duct, brain, breast, colon, prostate, ovary, pancreas, and lung cancers as well as various leukemias. HAAH is not found in measurable quantities in normal tissue (n > 500), including normal adjacent tissue within cancer biopsy specimens or in benign proliferative disorders. We have developed a fully human antibody against HAAH, PAN-622,that displays exquisite specificity for cancer. Here we explore PAN-622 drug conjugates for ultimate use in treating both hematologic and solid tumors. PAN-622 was conjugated to three different drugs: a maytansinoid (DM1), monomethyl auristatin E (MMAE), and duocarmycin (DUO). DM1 was conjugated via a noncleavable thio-ether linker while MMAE and DUO were conjugated using valine-citruline containing linkers that are cleavable by cathepsin B in the endosomal compartment. Conjugation of drugs to the PAN-622 antibody had little effect on the affinity of the antibody for HAAH. Binding affinities were determined by immunoassay on fixed cancer cells (H460, human lung cancer line) and were ~0.1, 0.2, and 0.5nM for PAN-622-DM1, PAN-622-MMAE, and PAN-622-DUO, respectively. The affinity of PAN-622 for HAAH as expressed on live cells has previously been shown to be ~1nM. Efficacies of the three ADCs for killing of H460 cells were determined using an MTS assay. The PAN-622-DM1 had an EC50 of ~15nM. The EC50 for PAN-622-MMAE was ~60nM, and that for PAN-622-DUO was ~300nM. Importantly, both unconjugated PAN-622 and a nonrelevant antibody conjugated to MMAE did not display any killing of the H460 cell line. Efficacy was also measured on a representative hematologic cancer line, MOLM-14 (acute myelogenous leukemia) where EC50s were in the 20-50nM range for all three ADCs. This work serves as a proof of concept, laying the groundwork for further development of HAAH-targeted ADCs. Citation Format: Kanam Malhotra, Susan Walker, Chen Fang, Karamveer Birthare, Michael S. Lebowitz, Steven Fuller, Muctarr Sesay, Hossein A. Ghanbari. Antibody-drug conjugates targeted at human aspartyl (asparaginyl) β-hydroxylase [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B106.

Abstract B046: A novel adjuvant for the treatment of obesity-related cancers

Abstract Obesity is pandemic and linked to higher incidence and poorer prognosis of several cancers, including pancreatic cancer (PC), triple-negative breast cancer (TNBC), and endometrial cancer type II (EmCa), which do not have targeted therapy. Commonly, patients suffering from these diseases are treated with chemotherapeutics. However, they develop acquired drug resistance, which are additional unmet needs. The specific mechanisms involved in obesity-related cancer are still not completely known. However, chemoresistance is related to the actions of a population of cancer cells with self-renewal capabilities, currently identified as cancer stem cells (CSC). A potential link between obesity and cancer is leptin, the major adipokine secreted by adipose tissue and cancer cells. Leptin levels are increased in obese individuals, which could increase the progression of cancer. Moreover, leptin’s actions could be detrimental to chemotherapeutic efficacy. Leptin induces Notch expression in PC, TNBC, and EmCa, which supports cell proliferation and survival, and is a potent CSC stimulator. It is hypothesized that leptin-Notch signaling is essential for cancer stemness and development of drug resistance. Our data show that leptin induces cancer cell proliferation, the progression of cell cycle, and increases cancer xenograft growth. These leptin effects were found together with a significant stimulation of CSC and reduced response to several chemotherapeutics. Remarkably, the use of a proprietary, very specific, and potent inhibitor of leptin signaling bound to iron-oxide nanoparticles, IONP-LPrA2, significantly reduced leptin-induced effects in cancer cells and xenografts, and increased the effectiveness of chemotherapeutics. LPrA2 has absolute affinity by the leptin receptor, Ob-R, which is expressed higher by cancer cells. IONP-LPrA2 theranostic properties could serve to simultaneously monitor and treat cancer by detecting primary and metastasic tumors via magnetic resonance imagining. A remarkable compelling advantage of this approach is that LPrA2 has no toxicity and does not affect health status, appetite, body weight, or energy balance in mice. Present results suggest that IONP-LPrA2 combined with chemotherapeutics could be an innovative targeted adjuvant therapy for obesity-related cancers. Supported by the National Institute on Minority Health and Health Disparities (NIMHD) of the National Institutes of Health under Award Number 5S21MD000101, and DOD W81XWH-13-1-0382; NIH/NCI 1R41CA183399-01A1; Pilot Project Award from MSM/Tuskegee University/UAB Cancer Center Partnership grant 5U54CA118638; and facilities and support services at MSM (1G12RR026250-03; NIH RR 03034 and 1C06 RR18386). Citation Format: Ruben R. Gonzalez, Adriana Harbuzariu, Danielle Daley-Brown, Tia Harmon, Viola Lanier, Sha'kayla Nunez, Ann Kurian, Crystal Lipsey. A novel adjuvant for the treatment of obesity-related cancers [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B046.

LncRNA PCGEM1 Induces Ovarian Carcinoma Tumorigenesis and Progression Through RhoA Pathway

Background/Aims: Prostate cancer gene expression marker 1 (PCGEM1) is a long noncoding RNA (lncRNA) and is well known as a promoter in prostate cancer and osteoarthritis synoviocytes. However, the role PCGEM1 plays in epithelial ovarian cancer is unknown. Methods: PCGEM1 expression was examined in epithelial ovarian cancer and normal ovarian tissues using reverse transcription–PCR. Ovarian cancer cell phenotypes and genotypes were examined after PCGEM1 overexpression or downregulation in vitro; besides, the effects of PCGEM1 overexpression was also examined in vivo. Results: PCGEM1 expression level was higher in epithelial ovarian cancer tissues than in normal ovarian tissues and was positively associated with differentiation (Well vs. Mod/Poor). Upregulation of PCGEM1 induced cancer cell proliferation, migration, and invasion, but decreased cell apoptosis through upregulating RhoA, YAP (Yes-associated protein), MMP2 (matrix metalloproteinase 2), Bcl-xL, and P70S6K expression; while PCGEM1 downregulation had the opposite effect. The nude mouse xenograft assay demonstrated that PCGEM1 overexpression promoted tumor growth. Furthermore, silencing RhoA expression reversed the effect of PCGEM1 and significantly inhibited RhoA, YAP, MMP2, Bcl-xL, and P70S6K protein expression. Conclusion: In conclusion, we suggest that PCGEM1 may be an inducer in epithelial ovarian cancer tumorigenesis and progression by upregulating RhoA and the subsequent expression of YAP, P70S6K, MMP2, and Bcl-xL.

KCTD12 promotes tumorigenesis by facilitating CDC25B/CDK1/Aurora A-dependent G2/M transition

Cell cycle dysregulation leads to uncontrolled cell proliferation and tumorigenesis. Understanding the molecular mechanisms underlying cell cycle progression can provide clues leading to the identification of key proteins involved in cancer development. In this study, we performed proteomics analysis to identify novel regulators of the cell cycle. We found that potassium channel tetramerization domain containing 12 (KCTD12) was significantly upregulated in M phase compared with S phase. We also found that KCTD12 overexpression not only facilitated the G2/M transition and induced cancer cell proliferation, but also promoted the growth of subcutaneous tumors and Ki-67 proliferation index in mice. Regarding the mechanism underlying these phenomena, cyclin-dependent kinase 1 (CDK1) was identified as an interacting partner of KCTD12 by immunoprecipitation and mass spectrometry analysis, which showed that KCTD12 activated CDK1 and Aurora kinase A (Aurora A) and that the effects of KCTD12 on CDK1 phosphorylation and cell proliferation were abrogated by cell division cycle 25B (CDC25B) silencing. In addition, Aurora A phosphorylated KCTD12 at serine 243, thereby initiating a positive feedback loop necessary for KCTD12 to exert its cancer-promoting effects. Furthermore, we analyzed the expression levels of various genes and the correlations between the expression of these genes and survival using tumor tissue microarray and Gene Expression Omnibus (GEO) data sets. The data showed that KCTD12 expression was significantly upregulated in cervical and lung cancers. More importantly, high KCTD12 expression was associated with larger tumor sizes, higher pathological stages and poor patient survival. Collectively, our study demonstrate that KCTD12 binds to CDC25B and activates CDK1 and Aurora A to facilitate the G2/M transition and promote tumorigenesis and that Aurora A phosphorylates KCTD12 at serine 243 to trigger a positive feedback loop, thereby potentiating the effects of KCTD12. Thus, the KCTD12-CDC25B-CDK1-Aurora A axis has important implications for cancer diagnoses and prognoses.

Integrated genomic analysis of clear cell ovarian cancers identified PRKCI as a potential therapeutic target.

Clear cell ovarian cancer (CCOC) is an epithelial ovarian cancer histotype with unique pathologic, biologic and clinical features. Despite its worse prognosis than serous ovarian cancer (SOC), the genomic landscape of CCOC is less well defined. Integrated genomic analysis of CCOC allows the identification of potential therapeutic targets to improve the treatment of this tumor. Using comparative genomic hybridization and gene expression profiling, we have screened 12 CCOC cell lines and 40 tumors to identify 45 amplified and overexpressed genes. Pathways analysis of these genes identified 19 genes with cancer-related functions. Of these, PRKCI is one of the most frequently amplified and overexpressed genes and its expression induced cancer cell proliferation and migration/invasion in vitro as well as tumor growth in vivo. Targeting PRKCI by small molecule inhibitor, sodium aurothiomalate (ATM), significantly reduced the in vivo tumor growth and may be a new therapeutic strategy to improve the treatment of CCOC.

Abstract 2650: Radioimmunotherapy for acute myeloid leukemia targeting human aspartyl (asparaginyl) β-hydroxylase

Abstract Treatment options for acute myeloid leukemia (AML) are limited and have modest impact on 5-year survival rates in patients <60 years of age (~35-40%) and on median survival of older patients (< 1 year). The incidence of AML has been rising, with an anticipated 19,950 new cases in 2016. Thus, the need for novel, more efficacious and better tolerated therapy for AML is urgent. Human aspartyl (asparaginyl) β-hydroxylase (HAAH) is an embryonic/developmental protein, which is down-regulated in normal cells after birth but overexpressed on the surface of many malignant cells, where it has been demonstrated to be sufficient to induce cancer cell proliferation, motility and invasiveness. We hypothesized that HAAH is selectively overexpressed on leukemia cells and thus targeting it with a fully human monoclonal antibody (mAb) conjugated to the short half-life α-emitter 213Bi could provide a novel radioimmunotherapy (RIT) treatment option with a reasonable therapeutic index. Using immunocytochemistry and flow cytometry with anti-HAAH mouse mAbs as well as a fully human mAb, PAN-622, we investigated the expression of HAAH on a variety of cytogenetically- and mutationally heterogeneous leukemia cell lines, including MV4-11, MOLM-14, HL-60, KG1α, Kasumi-1, K562, J45.1, and CCRF-CEM, as well as on normal human leukocytes. PAN-622 was further modified with DTPA-maleimide to allow chelation of radionuclides, specifically 213Bi, to the antibody. The 213Bi-DTPA-PAN-622 was then employed in killing assays to measure selective dose-dependent killing of leukemic cells. HAAH was highly expressed, as detected by flow cytometry, on all tested leukemia cell lines with KG1α and HL-60 demonstrating the highest levels of expression amongst the AML lines. Binding was observed by both PAN-622 and the modified DTPA-PAN-622 conjugate. Interestingly, expression of HAAH was not detected on CD45+ normal human leukocytes, including in subpopulations of monocytes (CD14+), B-cells (CD19+), T-cells (CD3+) or hematopoietic stem cells (CD34+). To determine whether PAN-622 could selectively target leukemia cells in a background of normal human blood, flow cytometry was performed on leukemia cells spiked into whole blood. Only leukemia cells were stained with the PAN-622 antibody as indicated by simultaneous staining for surface markers specific to the various leukocyte subpopulations. Selective killing of leukemia cell lines was demonstrated following incubation with 213Bi-DTPA-PAN-622 which induced dose dependent specific killing over a 6.7-670 pM concentration range. No killing was detected when using 213Bi conjugated to an isotype-matched control antibody at a similar specific activity and dose range. Thus, HAAH is a novel oncogenic target expressed on leukemia cells, which can be selectively targeted for RIT via the fully-human PAN-622 mAb. Experiments targeting primary leukemia cells in patient-derived bone marrow aspirates are ongoing. Citation Format: Michael S. Lebowitz, Ekaterina Revskaya, Kanam Malhotra, Amir Shahlaee, Steven Fuller, Maria R. Baer, Noa G. Holtzman, Ashkan Emadi, Ekaterina Dadachova, Hossein A. Ghanbari. Radioimmunotherapy for acute myeloid leukemia targeting human aspartyl (asparaginyl) β-hydroxylase [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2650. doi:10.1158/1538-7445.AM2017-2650

Knockdown of MALAT1 expression inhibits HUVEC proliferation by upregulation of miR-320a and downregulation of FOXM1 expression.

Regulation of cancer angiogenesis could be a useful strategy in cancer therapy. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a long non-coding RNA (lncRNA), and can induce cancer cell proliferation, while lncRNAs, generally are able to act as microRNA (miRNA) sponges. The latter is a type of competitive endogenous RNA (ceRNA) that regulates expression of the targeting miRNAs and protein-coding genes. This study investigated the proliferative role of MALAT1 in human umbilical vein endothelial cells (HUVECs) and the underlying molecular events. The data showed that knockdown of MALAT1 expression using MALAT1 siRNA inhibited HUVEC proliferation and also significantly decreased levels of FOXM1 mRNA and protein in vitro, while knockdown of FOXM1 expression reduced HUVEC proliferation. Annotation of HUVEC microarray data revealed that seven miRNAs, including miR-320a, were upregulated after knockdown of MALAT1 expression in HUVECs. MALAT1 was shown to reciprocally interact with miR-320a, i.e., expression of one negatively regulated levels of the other, whereas knockdown of MALAT1 expression promoted miR-320a levels. Furthermore, miR-320a could directly target and inhibit FOXM1 expression in HUVECs. Knockdown of MALAT1 expression enhanced miR-320a expression but reduced FOXM1 expression resulting in downregulation of HUVEC proliferation. However, such an effect was inhibited by miR-320a depletion. In conclusion, this study demonstrates that miR-320a plays an important role in mediating the effects of MALAT1 on HUVEC proliferation by suppression of FOXM1 expression. Thus, targeting of this gene pathway could be a novel strategy in cancer therapy.

SIRT1 promotes the proliferation and metastasis of human pancreatic cancer cells.

SIRT1 plays an important role in human malignant progression, inducing cancer cell proliferation and metastasis by regulating downstream gene expressions. However, little is known about the underlying mechanisms in which SIRT1 promotes pancreatic cancer tumorigenesis. The aim of this study is to investigate the SIRT1 expression levels and biological functions in promoting pancreatic cancer progression. We first investigated the expression of SIRT1 in a series of pancreatic cancer tissues as well as in a panel of pancreatic cancer cell lines. The effect of SIRT1 on cell activity was explored by knockdown experiments. Cell growth was measured using the MTT assay and colony-formation assay. Migration and invasion were tested using transwell assay. Our results showed that the expression of SIRT1 was significantly up-regulated both in pancreatic cancer tissues and cell lines. Knockdown of SIRT1 suppressed cell proliferation and migration of pancreatic cancer cells. This is the first report to disclose the role of SIRT1 in regulation of pancreatic cancer cell proliferation and migration, which may provide a potential therapeutic target for pancreatic cancer patients.

Aspirin therapy reduces the ability of platelets to promote colon and pancreatic cancer cell proliferation: Implications for the oncoprotein c-MYC.

Aspirin, an anti-inflammatory and antithrombotic drug, has become the focus of intense research as a potential anticancer agent owing to its ability to reduce tumor proliferation in vitro and to prevent tumorigenesis in patients. Studies have found an anticancer effect of aspirin when used in low, antiplatelet doses. However, the mechanisms through which low-dose aspirin works are poorly understood. In this study, we aimed to determine the effect of aspirin on the cross talk between platelets and cancer cells. For our study, we used two colon cancer cell lines isolated from the same donor but characterized by different metastatic potential, SW480 (nonmetastatic) and SW620 (metastatic) cancer cells, and a pancreatic cancer cell line, PANC-1 (nonmetastatic). We found that SW480 and PANC-1 cancer cell proliferation was potentiated by human platelets in a manner dependent on the upregulation and activation of the oncoprotein c-MYC. The ability of platelets to upregulate c-MYC and cancer cell proliferation was reversed by an antiplatelet concentration of aspirin. In conclusion, we show for the first time that inhibition of platelets by aspirin can affect their ability to induce cancer cell proliferation through the modulation of the c-MYC oncoprotein.

Effects of pharmacological ascorbate on hemoglobin-induced cancer cell proliferation

The high heme content in red meat is associated with an increased risk of developing cancer. Pharmacologic concentrations of ascorbate can specifically kill a wide range of cancer cells. In this study, the impact of ascorbate at pharmacologic concentrations on hemoglobin (Hb)-modulated human hepatoma HepG2 cell survival was investigated. It was found that HepG2 cells were proliferated by Hb (5⿿25μM), but killed by high pharmacologic concentrations of ascorbate (2⿿10mM). Although ascorbate at the low pharmacologic concentration (0.5mM) alone exhibited insignificant effect on cell viability, it effectively inhibited Hb (10μM)-induced cancer cell proliferation. The mechanism of this cytotoxicity was based on the production of extracellular H2O2 and involved transition iron. The influence of ascorbate on Hb-dependent redox reactions (i.e. the oxidative stability of Hb and its cytotoxic ferryl intermediate) was further investigated to illustrate the reaction mechanism of ascorbate toxicity, where H2O2 was generated in the reaction of ascorbate with Hb. Furthermore, circular dichroism demonstrated no significant change in the secondary structure of Hb after ascorbate addition and molecular docking revealed binding modes of ascorbate with Hb. These results demonstrated that ascorbate could possess anti-cancer activity through interfering in Hb-dependent redox reactions.

The combination of tetraiodothyroacetic acid and cetuximab inhibits cell proliferation in colorectal cancers with different K-ras status

Thyroid hormone induces cancer cell proliferation through its cell surface receptor integrin αvβ3. Acting via integrin αvβ3, the deaminated T4 analog tetraiodothyroacetic acid (tetrac), and its nanoparticle formulation nano-diamino-tetrac (NDAT) could inhibit cell proliferation and xenograft growth. In this study, we investigated the T4 effects on proliferation in colorectal cancer cell lines based on the proliferation marker expressions at both mRNA and protein levels. The effects of tetrac/NDAT, the monoclonal anti-EGFR antibody cetuximab, and their combinations on colorectal cancer cell proliferation were examined according to the relevant gene expression profiles and cell count analysis. The results showed that T4 significantly enhanced PCNA, Cyclin D1 and c-Myc levels in both K-ras wild type HT-29 and mutant HCT 116 cells. In HCT 116 cells, the combination of NDAT and cetuximab significantly suppressed the mRNA expressions of proliferative genes PCNA, Cyclin D1, c-Myc and RRM2 raised by T4 compared to cetuximab alone. In addition, T4-suppressed mRNA expressions of pro-apoptotic genes p53 and RRM2B could be significantly elevated by the combination of NDAT and cetuximab compared to cetuximab alone. In the K-ras mutant HCT 116 cells, but not in the K-ras wild type COLO 205 cells, the combinations of tetrac/NDAT and cetuximab significantly reduced cell proliferation compared to cetuximab alone. In conclusion, T4 promoted colorectal cancer cell proliferation which could be repressed by tetrac and NDAT. The combinations of tetrac/NDAT and cetuximab potentiated cetuximab actions in K-ras mutant colorectal cancer cells.