Aurora-A Expression Research Articles

Neutralizing IL-16 enhances the efficacy of targeting Aurora-A therapy in colorectal cancer with high lymphocyte infiltration through restoring anti-tumor immunity

Cancer cells can evade immune elimination by activating immunosuppressive signaling pathways in the tumor microenvironment (TME). Targeting immunosuppressive signaling pathways to promote antitumor immunity has become an attractive strategy for cancer therapy. Aurora-A is a well-known oncoprotein that plays a critical role in tumor progression, and its inhibition is considered a promising strategy for treating cancers. However, targeting Aurora-A has not yet got a breakthrough in clinical trials. Recent reports have indicated that inhibition of oncoproteins may reduce antitumor immunity, but the role of tumor-intrinsic Aurora-A in regulating antitumor immunity remains unclear. In this study, we demonstrated that in tumors with high lymphocyte infiltration (hot tumors), higher tumor-intrinsic Aurora-A expression is associated with a better prognosis in CRC patients. Mechanically, tumor-intrinsic Aurora-A promotes the cytotoxic activity of CD8+ T cells in immune hot CRC via negatively regulating interleukin-16 (IL-16), and the upregulation of IL-16 may impair the therapeutic effect of Aurora-A inhibition. Consequently, combination treatment with IL-16 neutralization improves the therapeutic response to Aurora-A inhibitors in immune hot CRC tumors. Our study provides evidence that tumor-intrinsic Aurora-A contributes to anti-tumor immunity depending on the status of lymphocyte infiltration, highlighting the importance of considering this aspect in cancer therapy targeting Aurora-A. Importantly, our results suggest that combining Aurora-A inhibitors with IL-16-neutralizing antibodies may represent a novel and effective approach for cancer therapy, particularly in tumors with high levels of lymphocyte infiltration.

Abstract 5169: Aurora-A kinase promotes anti-tumor immunity in high lymphocyte-infiltrated colorectal cancer

Abstract Introduction: The tumor microenvironment (TME) is composed of different cell types and is involved in tumor progression. Several immunosuppressive signaling pathways can promote tumor growth by inhibiting anti-tumor immunity in TEM. Therefore, targeting the immunosuppressive signaling pathways is a potential cancer treatment. Recent studies reported that inhibition of oncoproteins could lead to reduced anti-tumor immunity in several cancers; therefore, it’s critical to identify the potential oncoproteins which can lead to enhanced anti-tumor immunity. Aurora-A is a serine/threonine kinase that plays an important role in the centrosome, cell mitosis, and chromosome stability. Previous studies indicated that cancer patients with poor prognoses are associated with a high Aurora-A level in tumor cells. Inhibition of Aurora-A is considered as a promising strategy for cancer treatment. However, Aurora-A inhibitors have not had a breakthrough in phase II or phase III clinical trials. The role of Aurora-A in tumor immunity is still unclear. Here, we investigated the role of Aurora-A in tumor immunity. Materials and Methods: shRNA was used to knock down Aurora-A, and Alisertib was added to inhibit Aurora-A. RT-qPCR and western blot were performed to determine the IL-16 expression. The secretion of cytokines was measured by cytokine array and ELISA. BALB/c and NOD/SCID mice were subcutaneously injected with CT26 and then administered daily with Alisertib or treated with anti-IL-16 antibody. The tumor-infiltrating immune populations were analyzed by flow cytometry. IHC and H/E stain were performed to analyze Aurora-A expression and lymphocyte infiltration in human CRC specimens. Results: CRC patients with lower lymphocyte infiltration and higher Aurora-A are associated with poor prognosis and vice versa. Knockdown of Aurora-A in CT26 promotes tumor growth in immunocompetent mice by inhibiting the infiltration and cytotoxic activity of CD8+ T cells. Aurora-A negatively regulates IL-16 expression in a kinase-dependent manner in CRC cells. Blockade of IL-16 by anti-IL-16 antibody can reverse the tumor growth and CD8+ T cell cytotoxic activity in Aurora-A knocked-down CT26 tumors. Alisertib can inhibit CT26 tumor growth and promote IL-16 secretion in TME in mice. A combination of Alisertib and IL-16 antibody can promote the therapeutic effect of Alisertib in CT26 tumors. Conclusion: Tumor-intrinsic Aurora-A plays a diverse role in tumor progression depending on the status of lymphocyte infiltration in TME. Aurora-A can promote anti-tumor immunity via negatively regulating IL-16 in a kinase activity-dependent manner in hot CRC tumors. In tumors with high lymphocyte infiltration, Aurora-A inhibition can suppress cancer cell growth and reduce anti-tumor immunity; the combination of Aurora-A inhibitors and IL-16 antibodies may provide a novel and effective strategy for cancer therapy in hot tumors. Citation Format: Shiang-Jie Yang, Ming-Derg Lai, Liang-Yi Hung. Aurora-A kinase promotes anti-tumor immunity in high lymphocyte-infiltrated colorectal cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5169.

Targeting Aurora-A inhibits tumor progression and sensitizes thyroid carcinoma to Sorafenib by decreasing PFKFB3-mediated glycolysis

Thyroid cancer (TC) is the most common endocrine tumor, amongst which anaplastic thyroid carcinoma (ATC) is the most deadly. Aurora-A usually functions as oncogenes, and its inhibitor Alisertib exerts a powerful antitumor effect in various tumors. However, the mechanism of Aurora-A in regulating TC cell energy supply remains unclear. In the present study, we demonstrated the antitumor effect of Alisertib and an association between high Aurora-A expression and shorter survival. Multi-omics data and in vitro validation data suggested that Aurora-A induced PFKFB3-mediated glycolysis to increase ATP supply, which significantly upregulated the phosphorylation of ERK and AKT. Furthermore, the combination of Alisertib and Sorafenib had a synergistic effect, further confirmed in xenograft models and in vitro. Collectively, our study provides compelling evidence of the prognostic value of Aurora-A expression and suggests that Aurora-A upregulates PFKFB3-mediated glycolysis to enhance ATP supply and promote TC progression. Combining Alisertib with Sorafenib has huge prospects for application in treating advanced thyroid carcinoma.

The involvement of Aurora-A and p53 in oxaliplatin-resistant colon cancer cells.

Resistance to chemotherapy is the deadlock in cancer treatment. In this study, we used wild-type LOVO (LOVOWT ), a human colon cancer cell line, and the oxaliplatin-resistant sub-clone LOVOOR cells to investigate the molecular mechanisms of the development of drug resistance in colon cancer. Compared with LOVOWT cells, LOVOOR cells had a high proliferation capacity and a high percentage on the G2/M phase. The expression and activation of Aurora-A, a critical kinase in G2/M phase, were higher in LOVOOR cells than in LOVOWT cells. The results from immunofluorescence indicated an irregular distribution of Aurora-A in LOVOOR cells. To evaluate the importance of Aurora-A in oxaliplatin-resistant property of LOVOOR cells, overexpression of Aurora-A in LOVOWT cells and otherwise knockdown of Aurora-A in LOVOOR cells were performed and followed by administration of oxaliplatin. The results indicated that Aurora-A might contribute to the resistance of LOVOOR cells to oxaliplatin treatment by depressing p53 signaling. The specific findings in this study provide a possibility that targeting Aurora-A might be a solution for patients who have failed oxaliplatin treatment.

Abstract 115: Combined treatment of letrozole or olaparib with aspirin inhibits cell proliferation and induces apoptosis through upregulation of wild p53 and modulation of aurora kinases in human breast cancer cell lines

Abstract Although, there are several breakthroughs in the treatment of breast cancer on the past few decades, high incidence of relapse and progression after conventional therapies is deeply concerning, indicating a great need for developing new therapeutics for breast cancer. In the present study, the anti-cancer effects of combinational therapy of Letrozole (Aromatase inhibitor) or Olaparib (PARP inhibitor) with Aspirin, non-steroidal anti-inflammatory drugs (NSAIDs), were examined on well differentiated ER-positive and poorly differentiated triple negative breast cancer cell lines, T-47D and MDA-MB-231, respectively. In addition, the effect of combined treatment was also examined by detecting cell survival, cell cycle analysis, and alterations in signaling pathway that play a role in breast cancer progression such as β -catenin, STAT3, cyclin D1, Bax, c-PARP, wild and Mutant p53. In addition the effect of combined treatments were examined on gene expression levels of Cytochromes; CYP1A1, CYP1B1, Aurora kinases; Aurora-A and Aurora-B were determined by RT-PCR.Our data showed that combined treatments of 50 nmol Letrozole or 250 nmol Olaparib with 5 mmol, 2.5mmol Aspirin for 24 and 48 h, respectively, promoted apoptosis induction through enhanced histone release and caspase-3 activation compared to control and cells treated with each drug alone. Furthermore, apoptotic induction was associated with upregulation of Bax and downregulation of Bcl-2, cyclin D1, β-catenin, and STAT3 signaling pathways in both tested cell lines compared to control, suggesting that Aspirin may enhance the sensitivity of tested cells to Letrozole or Olaparib in both (ER) positive and triple negative breast cancer cell lines. In addition, cell cycle analysis showed a cell arrest at G0/G1 phase in both cell lines. Interestingly, in T-47D cells, combined treatment of Letrozole with Aspirin significantly upregulated wild p53 at protein level and downregulated CYP1A1, CYP1B1, Aurora-A, and Aurora-B expression at gene level compared to control, suggesting that combined treatment may inhibit breast cancer cell proliferation via down-regulation of Aurora-A and Aurora-B. In MDA-MB-231 cells, combined treatment of Olaparib with Aspirin showed a significant downregulation of Mutant p53 at protein level and CYP1A1, CYP1B1, Aurora-B and upregulation of Aurora-A at gene level compared to control, suggesting that there is a crosstalk between Olaparib/Aspirin and P53 In conclusion, combined treatment of Letrozole or Olaparib with Aspirin might be a promising approach to inhibit both ER (+) and triple negative breast cancer cell lines survival and proliferation. Citation Format: Marwa Elsayed ElKamel, Salah Sheweita, Ahmed Sultan. Combined treatment of letrozole or olaparib with aspirin inhibits cell proliferation and induces apoptosis through upregulation of wild p53 and modulation of aurora kinases in human breast cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 115.

Aurora-A kinase is differentially expressed in the nucleus and cytoplasm in normal M\xfcllerian epithelium and benign, borderline and malignant serous ovarian neoplasms

BackgroundAurora-A kinase is important for cellular proliferation and is implicated in the tumorigenesis of several malignancies, including of the ovary. Information regarding the expression patterns of Aurora-A in normal Müllerian epithelium as well as benign, borderline and malignant epithelial ovarian neoplasms is limited.MethodsWe investigated Aurora-A expression by immunohistochemistry in 15 benign, 19 borderline and 17 malignant ovarian serous tumors, and 16 benign, 8 borderline, and 2 malignant ovarian mucinous tumors. Twelve fimbriae from seven patients served as normal Müllerian epithelium controls. We also examined Aurora-A protein expression by western blot in normal fimbriae and tumor specimens.ResultsAll normal fimbriae (n = 12) showed nuclear but not cytoplasmic Aurora-A immunoreactivity by immunohistochemistry. Benign ovarian tumors also showed strong nuclear Aurora-A immunoreactivity. Forty-eight percent (13/27) of borderline tumors demonstrated nuclear Aurora-A immunoreactivity, while the remainder (52%, 14/27) lacked Aurora-A staining. Nuclear Aurora-A immunoreactivity was absent in all malignant serous tumors, however, 47% (8/17) demonstrated perinuclear cytoplasmic staining. These results were statistically significant when tumor class (benign/borderline/malignant) was compared to immunoreactivity localization or intensity (Fisher Exact Test, p < 0.01). Western blot analysis confirmed the greater nuclear Aurora-A expression in control Müllerian epithelium compared to borderline and malignant tumors.ConclusionAurora-A kinase is differentially expressed across normal Müllerian epithelium, benign and borderline serous and mucinous ovarian epithelial neoplasms and malignant serous ovarian tumors., with nuclear expression of unphosphorylated Aurora-A being present in normal and benign neoplastic epithelium, and lost in malignant serous neoplasms. Further studies of the possible biological and clinical implications of the loss of nuclear Aurora-A expression in ovarian tumors, and its role in ovarian carcinogenesis are warranted.

Abstract 1441: Aspirin in combination with Letrozole or Olaparib induced apoptosis in estrogen receptor-positive T-47D &amp; triple negative MDA-MB-231 breast cancer cell lines

Abstract Breast cancer is the most commonly diagnosed type of cancer and leading cause of cancer-related death among women worldwide. Although there are several breakthroughs in the treatment of breast cancer on the past few decades, high incidence of relapse and progression after conventional therapies is deeply concerning, indicating a great need for developing new therapeutics for breast cancer. Strategies including utilization of combined treatments in order to enhance the efficacy of cancer treatment have been widely developed in recent years, targeting different signaling pathways to inhibit proliferation or induce apoptosis. In the present study, the anti-cancer effects of combinational therapy of Letrozole (Aromatase inhibitor) or Olaparib (PARP inhibitor) with Aspirin, non-steroidal anti- inflammatory drugs (NSAIDs), were examined on well differentiated ER-positive and poorly differentiated triple negative breast cancer cell lines, T-47D and MDA-MB-231, respectively. In addition, The effect of combined treatment was also examined by detecting cell survival, cell cycle analysis, and alterations in signaling pathway that play a role in breast cancer progression such as β -catenin, STAT3, cyclin D1, BAX, c-PARP, wild and Mutant p53. In addition the effect of combined treatments were examined on gene expression levels of Cytochromes; CYP1A1, CYP1B1, Aurora kinases; Aurora-A and Aurora-B were determined by RT-PCR. Our data showed that combined treatments of 50 nm Letrozole or 250 nm Olaparib with 5mm, 2.5mm Aspirin for 48 &amp; 24 h respectively promoted apoptosis induction through enhanced histone release and caspase-3 activation compared to control and cells treated with each drug alone. Furthermore, apoptotic induction was associated with upregulation of Bax and downregulation of cyclin D1, β-catenin, and STAT3 signaling pathways in both tested cell lines compared to control, suggesting that Aspirin may enhance the sensitivity of tested cells to Letrozole or Olaparib in both (ER) positive as well as in triple negative breast cancer cell lines. In addition, cell cycle analysis showed a cell arrest at G0/G1 phase in both cell lines. Interestingly, in T-47D cells, combined treatment of Letrozole with Aspirin significantly upregulated wild p53 at protein level and downregulated CYP1A1, CYP1B1, Aurora-A, and Aurora-B expression at gene level compared to control, suggesting that combined treatment may inhibit breast cancer cell proliferation via down-regulation of Aurora-A and Aurora-B. In MDA- MB-231 cells, combined treatment of Olaparib with Aspirin showed a significant downregulation of Mutant p53 at protein level and CYP1A1, CYP1B1, Aurora-B and upregulation of Aurora-A at gene level compared to control, suggesting that there is a crosstalk between Olaparib/ Aspirin and P53. In conclusion, combined treatment of Letrozole or, Olaparib with Aspirin might be a promising approach to inhibit both ER (+) and triple negative breast cancer cell lines survival and proliferation. Citation Format: Marwa El Sayed El Kamel, Salah Ahmed Sheweita, Ahmed Samir Sultan. Aspirin in combination with Letrozole or Olaparib induced apoptosis in estrogen receptor-positive T-47D &amp; triple negative MDA-MB-231 breast cancer cell lines [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1441.

Abstract A32: Selective inhibition of AuroraA by LY3295668 erbumine in neuroblastoma models induces apoptosis through a combination of S-phase DNA damage and mitotic arrest

Abstract Aurora kinase A (AuroraA) is a serine/threonine protein kinase critical for centrosome maturation, mitotic spindle formation, and spindle checkpoint activation. Aberrant expression of AuroraA promotes tumor initiation and disease progression, making it a promising therapeutic target in several cancer types. However, recent clinical trials of purported selective AuroraA inhibitors failed due to lack of efficacy and/or hematologic toxicity, likely due to concurrent inhibition of Aurora kinase B (AuroraB). Selective AuroraA inhibition leads to mitotic arrest and apoptosis, while AuroraB inhibition causes persistent DNA endoreduplication and polyploidy leading to genomic instability. LY3295668 erbumine (LY3295668) is a selective AuroraA inhibitor with preclinical activity in multiple models of cancer including neuroblastoma (NBL). High-risk NBL, a devastating pediatric cancer with few effective treatment options, is mainly stratified by MYCN amplification status. In NBL, AuroraA stabilizes N-MYC post-transcriptionally; moreover, AuroraA also controls N-MYC-dependent transcription during S-phase. Here, we evaluated LY3295668 in multiple NBL cell lines and in vivo mouse models where treatment resulted in apoptosis and tumor regressions, respectively. We compared LY3295668 to alisertib (a dual AuroraA/B inhibitor) in multiple cell-based assays that differentiate AuroraA activity from that of AuroraB and showed that LY3295668 has a distinct pharmacologic profile from alisertib. In addition, we determined the mechanism of action for LY3295668 includes DNA damage prior to mitotic block. Our results further support that AuroraA controls MYC-dependent transcription in S-phase and selective inhibition of AuroraA with LY3295668 promotes transcription-replication conflicts leading to DNA damage. In addition to AuroraA-mediated mitotic arrest, this DNA damage may contribute to the hypersensitivity of MYC-driven tumors such as NBL. In summary, LY3295668 is a selective AuroraA inhibitor with a dual mechanism of action in NBL involving DNA damage in S-phase and a cell cycle block in mitosis. These combined activities contribute to sensitivity of preclinical NBL models. Citation Format: Michele Dowless, Jill Kremer, Caitlin Lowery, Xueqian Gong, Joseph Klahn, Jennifer Stephens, Yu-Hua Hui, Wayne Blosser, Ricardo Martinez, Jian Du, Louis Stancato. Selective inhibition of AuroraA by LY3295668 erbumine in neuroblastoma models induces apoptosis through a combination of S-phase DNA damage and mitotic arrest [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr A32.

Targeting the protein-protein interface pocket of Aurora-A-TPX2 complex: rational drug design and validation

Aurora-A is a novel therapeutic target that belongs to the serine/threonine kinase family of proteins. Several cancers are associated with gene amplification or over-expression of Aurora-A. The somatic mutation (S155R) in Aurora-A results in a loss of interaction with its binding partner TPX2. The S155R mutation thus leads to ectopic expression of Aurora-A, resulting in centrosome amplification, chromosomal instability, aneuploidy, and oncogenic transformations. In order to restore the interaction between mutant Aurora-A and TPX2, we predicted a binding pocket in the interface of the Aurora-A-TPX2 complex. We performed molecular docking of potential bioactive molecules of the Himalayan region at the predicted site. Alantolactone and Dactylose-A were selected as potential molecules that could bind to the interface pocket and restore the lost interaction between mutant Aurora-A and TPX2. The molecular docking results were validated by performing explicit long term molecular dynamics simulations (4.0 μs) and MM-PBSA analysis. The molecular dynamics results confirmed that both the selected molecules could act as potent drugs to tackle the abnormal expression of Aurora-A manifested due to the somatic mutation (S155R). Communicated by Ramaswamy H. Sarma

Long Noncoding RNA MALAT1 Contributes to Sorafenib Resistance by Targeting miR-140-5p/Aurora-A Signaling in Hepatocellular Carcinoma.

Long noncoding RNAs (lncRNA) have been found to play critical roles in tumorigenesis and the development of various cancers, including hepatocellular carcinoma (HCC). Metastasis associated with lung adenocarcinoma transcript-1 (MALAT1) has been identified as an oncogene and prognostic biomarker in HCC. Here, we demonstrated that MALAT1 expression was obviously high in sorafenib-resistant HCC cells. Furthermore, knockdown of MALAT1 increased sorafenib sensitivity in nonresponsive HCC cells, whereas forced expression of MALAT1 conferred sorafenib resistance to responsive HCC cells in vitro In addition, loss/gain-of-function assays revealed that MALAT1 promoted cell proliferation, migration, and epithelial-mesenchymal transition in HCC cells. Mechanistically, MALAT1 regulated Aurora-A expression by sponging miR-140-5p, thus promoting sorafenib resistance in HCC cells. Moreover, MALAT1 inhibition enhanced the antitumor efficacy of sorafenib in vivo Clinically, we found that MALAT1 expression was negatively correlated with miR-140-5p expression but positively correlated with Aurora-A expression in patients with HCC and that upregulated MALAT1 was closely correlated with poor survival outcomes in patients with HCC. These findings indicated that MALAT1 may be a novel target for prognosis prediction and therapeutic strategies in patients with HCC treated with sorafenib.

Expression of FOXM1 and Aurora-A predicts prognosis and sorafenib efficacy in patients with hepatocellular carcinoma.

BACKGROUND: Effective prognostic biomarkers and powerful target-therapeutic drugs are needed for improving the treatment of Hepatocellular carcinoma (HCC).OBJECTIVE: This study aimed to evaluate the expression of FOXM1 and Aurora-A and their prognostic value in HCC.METHODS: We determined the differentially expressed genes signature in HCC using the Gene Set Enrichment Analysis (GSEA), and then evaluated the expression of FOXM1 and Aurora-A in TCGA and KMUH cohort. Associations between co-expression of FOXM1 and Aurora-A and clinical variables were calculated. Overall survival (OS) and recurrence-free survival (RFS) were estimated with different FOXM1 and Aurora-A expression status.RESULTS: FOXM1-related gene sets were mostly associated with cell cycle regulation in HCC tissues. We found a positive correlation between the expression of FOXM1 and Aurora-A. Overexpression of FOXM1 and Aurora-A was associated with larger tumor size, advanced stage, higher grade, and double-positive for HBV and HCV. The coordinated overexpression of FOXM1 and Aurora-A was the most significant independent prognostic factor for OS and RFS. Furthermore, the concomitant high expression of FOXM1 and Aurora-A predicted the worst OS of sorafenib-treated patients with HCC.CONCLUSIONS: The co-expression of FOXM1 and Aurora-A could be a reliable biomarker to predict the sorafenib response and prognosis of HCC patients.

A selective Aurora-A 5'-UTR siRNA inhibits tumor growth and metastasis.

Many Aurora-A inhibitors have been developed for cancer therapy; however, the specificity and safety of Aurora-A inhibitors remain uncertain. The Aurora-A mRNA yields nine different 5'-UTR isoforms, which result from mRNA alternative splicing. Interestingly, we found that the exon 2-containing Aurora-A mRNA isoforms are predominantly expressed in cancer cell lines as well as human colorectal cancer tissues, making the Aurora-A mRNA exon 2 a promising treatment target in Aurora-A-overexpressing cancers. In this study, a selective siRNA, siRNA-2, which targets Aurora-A mRNA exon 2, was designed to translationally inhibit the expression of Aurora-A in cancer cells but not normal cells; locked nucleic acid (LNA)-modified siRNA-2 showed improved efficacy in inhibiting Aurora-A mRNA translation and tumor growth. Xenograft animal models combined with noninvasion in vivo imaging system (IVIS) analysis further confirmed the anticancer effect of LNA-siRNA-2 with improved efficiency and safety and reduced side effects. Mice orthotopically injected with colorectal cancer cells, LNA-siRNA-2 treatment not only inhibited the tumor growth but also blocked liver and lung metastasis. The results of our study suggest that LNA-siRNA-2 has the potential to be a novel therapeutic agent for cancer treatment.

Aurora kinase A stabilizes FOXM1 to enhance paclitaxel resistance in triple-negative breast cancer.

Triple‐negative breast cancer (TNBC) has a relatively poor outcome. Acquired chemoresistance is a major clinical challenge for TNBC patients. Previously, we reported that kinase‐dead Aurora kinase A (Aurora‐A) could effectively transactivate the FOXM1 promoter. Here, we demonstrate an additional pathway through which Aurora‐A stabilizes FOXM1 by attenuating its ubiquitin in TNBC. Specifically, Aurora‐A stabilizes FOXM1 in late M phase and early G1 phase of the cell cycle, which promotes proliferation of TNBC cells. Knock‐down of Aurora‐A significantly suppresses cell proliferation in TNBC cell lines and can be rescued by FOXM1 overexpression. We observe that paclitaxel‐resistant TNBC cells exhibit high expression of Aurora‐A and FOXM1. Overexpression of Aurora‐A offers TNBC cells an additional growth advantage and protection against paclitaxel. Moreover, Aurora‐A and FOXM1 could be simultaneously targeted by thiostrepton. Combination of thiostrepton and paclitaxel treatment reverses paclitaxel resistance and significantly inhibits cell proliferation. In conclusion, our study reveals additional mechanism through which Aurora‐A regulates FOXM1 and provides a new therapeutic strategy to treat paclitaxel‐resistant triple‐negative breast cancer.

Abstract 3016: Dicer overexpression contributes to chemoresistance in colorectal cancer via up-regulating a set of miRNAs

Abstract Chemotherapy has a good success rate in the treatment of colorectal cancer; however, recurrence of colorectal cancer is still frequent due to acquired resistance. Aurora-A, a cell cycle-regulated kinase, plays an important role in colorectal cancer development and drug resistance. Dicer, one of the key enzymes of the microRNA (miRNA) biogenesis pathway, may be involved in chemoresistance through regulating the expression of miRNAs. According to the TCGA database, the expression levels of Dicer and Aurora-A were increased in colorectal cancer, which may contribute to chemoresistance. Our results showed that the protein levels of Dicer and Aurora-A are increased in oxaliplatin resistant cell lines. Knocked-down expression of Dicer or Aurora-A can enhance drug sensitivity in oxaliplatin-resistant cells; in contrast, overexpression of Dicer or Aurora-A increased drug resistance in parental drug sensitive cells. By next-generation sequencing, we found that the expression of a set of miRNAs is increased in oxaliplatin resistant cells. Dicer overexpression enhances the expression of those miRNAs in drug sensitive parental cells. Clinical evaluation further confirmed the increased expression of those miRNA in the plasma of CRC patients with a poor response to oxaliplatin. Our results suggest that those miRNAs may act as biomarkers to predict oxaliplatin response in colorectal cancer by detecting their plasma miRNAs. The molecular mechanism of those miRNAs in regulating the drug response is currently under our investigation. Citation Format: Li Jyuan Lin, Liang-Yi Hung. Dicer overexpression contributes to chemoresistance in colorectal cancer via up-regulating a set of miRNAs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3016.

Abstract 4387: hnRNP Q1 promotes cell proliferation and tumorigenesis by translationally up-regulating cell cycle-related genes through the EGF pathway

Abstract Heterogeneous nuclear ribonucleoprotein (hnRNP) Q1, an RNA-binding protein, has been reported as overexpressing in cancer cells. However, the role of hnRNP Q1 in tumorigenesis remains unclear. By using RNA-immunoprecipitation (IP) assay following next-generation sequencing, a group of cell cycle-related genes targeted by hnRNP Q1 were identified, including Aurora-A kinase. Overexpressed hnNRP Q1 can up-regulate Aurora-A and many spindle assembly checkpoint (SAC) proteins, but not alter their mRNA levels, through enhancing translational efficiency by interacting with the mRNA 5’-UTR. Ribosomal S6-IP and ribosomal profiling assay further confirmed the translational regulation of these mRNAs by hnRNP Q1. Stimulation with epidermal growth factor (EGF) enhances both binding between hnRNP Q1 and these mRNAs as well as the efficacy of the hnRNP Q1-induced translation of these mRNAs. EGF/hnRNP Q1-induced translation is mediated by the mTOR and ERK pathways. In addition, hnRNP Q1 overexpression is positively correlated with the levels of Aurora-A and these SAC genes in human colorectal cancer tissues. Taken together, our data suggest that hnRNP Q1 plays an important role in translationally regulating the expression of Aurora-A and a group of cell cycle-related genes, which increases cell proliferation and contributes to tumorigenesis in colorectal cancer. It may thereby contribute to tumorigenesis by translationally up-regulating these genes in colorectal cancer. Citation Format: Liang-Yi Hung. hnRNP Q1 promotes cell proliferation and tumorigenesis by translationally up-regulating cell cycle-related genes through the EGF pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4387.

Abstract 315: Identification of distinct and targetable mechanisms of acquired resistance to CDK4/6 inhibitors

Abstract Recently, three CDK4/6 inhibitors were approved by FDA and became effective treatments for ER+ breast cancer patients. However, most if not all patients eventually progress on treatment . To identify mechanisms associated with acquired resistance to CDK4/6 inhibitors, we derived 15 CDK4/6i-resistant variants from human cancer cell lines highly sensitive to CDK4/6 inhibition with abemaciclib or palbociclib. Transcriptome and proteomic profiling of the derivatives revealed four general classes of alteration: decreased RB1, increased CCNE1 or CCNE2, increased ERK phosphorylation, and increased Aurora-A expression. A drug screen was employed to identify drugs or abemaciclib-drug combinations that could suppress growth of the resistant variants. Inhibitors of Aurora-A, Chk1 and the Ras-MAPK pathway were effective for the treatment of the respective classes of resistant derivative. Importantly, Rb loss, Aurora-A amplifications and Ras mutations were all observed as recurrent alterations in biopsies from ER+ breast cancer patients after progression on CDK4/6 inhibitors (1,2). Together these data demonstrate that cancer cells can escape from suppression by CDK4/6 drugs via multiple mechanisms and suggest clinically available therapeutic strategies to treat different classes of resistance. 1. S Wander et al, AACR, 2018 2. R Condorelli et al, Annals of Oncology, vol 29, issue 3, 640-645, 2017 Citation Format: Stephen Parsons. Identification of distinct and targetable mechanisms of acquired resistance to CDK4/6 inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 315.

Aurora-A Induces Chemoresistance Through Activation of the AKT/mTOR Pathway in Endometrial Cancer.

Endometrial cancer (EC) is the most common gynecological tumor all over the world, and advanced/metastatic EC remains a malignancy with poor survival outcome due to highly resistant to conventional chemotherapeutic treatment. Here, we report that Aurora-A, a serine-threonine kinase, plays a vital role in chemoresistance of EC. Aurora-A is overexpressed in EC tissues, compared with normal endometrium and Aurora-A expression is associated with decreased overall survival. Overexpression of Aurora-A in EC cell lines (Ishikawa and HEC-1B cells) promotes cell proliferation and induced paclitaxel- and cisplatin-resistance. Furthermore, Aurora-A activating AKT-mTOR pathway further induces chemoresistance in vitro, consistent with a positive correlation between Aurora-A and phosphorylated AKT/4E-BP1 expression in EC tissues. In summary, our study provides the strong evidence that Aurora-A controls the sensitivity of EC cell lines to chemotherapy via AKT/mTOR pathway, indicating that pharmacologic intervention of Aurora-A and AKT/mTOR in combination with chemotherapy may be considered for the targeted therapy against EC with overexpression of Aurora-A.

A new role for Drosophila Aurora-A in maintaining chromosome integrity.

Aurora-A is a conserved mitotic kinase overexpressed in many types of cancer. Growing evidence shows that Aurora-A plays a crucial role in DNA damage response (DDR) although this aspect has been less characterized. We isolated a new aur-A mutation, named aur-A949, in Drosophila, and we showed that it causes chromosome aberrations (CABs). In addition, aur-A949 mutants were sensitive to X-ray treatment and showed impaired γ-H2Av foci dissolution kinetics. To identify the pathway in which Aur-A works, we conducted an epistasis analysis by evaluating CAB frequencies in double mutants carrying aur-A949 mutation combined to mutations in genes related to DNA damage response (DDR). We found that mutations in tefu (ATM) and in the histone variant H2Av were epistatic over aur-A949 indicating that Aur-A works in DDR and that it is required for γ-H2Av foci dissolution. More interestingly, we found that a mutation in lig4, a gene belonging to the non-homologous end joining (NHEJ) repair pathway, was epistatic over aur-A949. Based on studies in other systems, which show that phosphorylation is important to target Lig4 for degradation, we hypothesized that in aur-A949 mutant cells, there is a persistence of Lig4 that could be, in the end, responsible for CABs. Finally, we observed a synergistic interaction between Aur-A and the homologous recombination (HR) repair system component Rad 51 in the process that converts chromatid deletions into isochromatid deletions. Altogether, these data indicate that Aur-A depletion can elicit chromosome damage. This conclusion should be taken into consideration, since some anticancer therapies are aimed at reducing Aurora-A expression.

Abstract 5890: Aurora-A potentiates chemoresistance via regulating the microRNA biogenesis pathway

Abstract Chemotherapy has a good success rate in colorectal cancer; however, recurrence of colorectal cancer is still frequent due to the development of drug resistance. MicroRNA (miRNA) is a type of non-coding RNA with a size of around 19-22 nucleotides and plays an important role in regulating many biological functions, the onset of diseases, as well as drug response. It was reported that Dicer, one of the key enzymes of the miRNA biogenesis pathway, may be involved in the chemoresistance through regulating the expression of miRNAs. Aurora-A, a cell cycle-regulated kinase, plays a vital role in cancer development and chemoresistance. According to the TCGA database, the expression levels of Dicer and Aurora-A are both increased in colorectal cancer. Here, we demonstrated that overexpressed Aurora-A can regulate the chemodrug response by influencing the miRNA biogenesis pathway via Dicer in colorectal cancer. Our results showed that the protein level, but not the mRNA expression, of Dicer was decreased upon 5-FU or oxaliplatin treatment in drug sensitive cells; whereas, the expression level of Dicer was increased in oxaliplatin resistant cell lines. Knockdown expression of Dicer in oxaliplatin resistant cell lines could reverse the resistance of oxaliplatin. The expression levels of several potential miRNAs changed upon chemodrugs treatment. Interestingly, we found that overexpressed Aurora-A could increase the expression of Dicer and potentiate drug resistance in colorectal cancer cells. In contrast, knockdown expression of Aurora-A decreased Dicer protein expression and led to enhanced drug sensitivity. Taken together, our results suggested that Aurora-A and Dicer can collaborate to regulate drug response through influencing the miRNA biogenesis pathway in colorectal cancer. The further mechanism of Dicer and Aurora-A in chemoresistance is currently under our investigation. Citation Format: Li Jyuan Lin. Aurora-A potentiates chemoresistance via regulating the microRNA biogenesis pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5890.

DNA replication licensing factor MCM2, geminin, and Ki67 define proliferative state and are linked with survival in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is still an unabated global killer with little advancement in its survival rate. DNA replication licensing proteins and Aurora kinase A are biomarkers that play important roles in genomic stability. The expression profile of minichromosomal maintenance protein 2 (MCM2), Ki67, geminin, and Aurora-A were linked to clinicopathological and outcome parameters, survival, and DNA content in 125 cases of OSCC. Oral fibroepithelial polyps (OFEP) were controls. The OSCC tumour cells were in a rapidly proliferating state, as assessed by the increased expression profile of MCM2, Ki67, geminin, and Aurora-A and of the geminin/Ki67 ratio, and the decrease of the MCM2/Ki67 ratio, in OSCC compared with OFEP (P<0.000). There was an association between expression of MCM2, Ki67, and geminin and tumour histologic and invasive front grade (P<0.05). A total of 82% of the OSCC assessed had aneuploid DNA content, which was associated with increased expression intensity of Aurora-A (P=0.01). Geminin and the geminin/Ki67 ratio were associated with TNM staging (P<0.05), and weak expression of MCM2, Ki67, geminin, and Aurora-A were predictive of OSCC survival (P<0.05). Dysregulation of the origin licensing pathway and the mitotic pathway are important events in OSCC, and the combined analysis of these proteins may contribute to improved treatment decisions.