Sorafenib is currently the only US Food and Drug Administration (FDA)-approved molecular inhibitor for the systemic therapy of advanced hepatocellular carcinoma (HCC). Aspirin has been studied extensively as an anti-inflammation, cancer preventive and therapeutic agent. However, the potential synergistic therapeutic effects of sorafenib and aspirin on advanced HCC treatment have not been well studied. Drug combination studies and their synergy quantification were performed using the combination index method of Chou-Talalay. The synergistic therapeutic effects of sorafenib and aspirin were evaluated using an orthotopic mouse model of HCC and comprehensive gene profiling analyses were conducted to identify key factors mediating the synergistic therapeutic effects of sorafenib and aspirin. Sorafenib was determined to act synergistically on HCC cells with aspirin in vitro. Using Hep3B and HuH7 HCC cells, it was demonstrated that sorafenib and aspirin acted synergistically to induce apoptosis. Mechanistic studies demonstrated that combining sorafenib and aspirin yielded significant synergistically anti-tumor effects by simultaneously silencing ACSL4 and the induction of GADD45B expression in HCC cells both in vitro and in the orthotopic HCC xenograft mouse model. Importantly, clinical evidence has independently corroborated that survival of HCC patients expressing ACSL4highGADD45Blow was significantly poorer compared to patients with ACSL4lowGADD45Bhigh, thus demonstrating the potential clinical value of combining aspirin and sorafenib for HCC patients expressing ACSL4highGADD45Blow. In conclusion, sorafenib and aspirin provide synergistic therapeutic effects on HCC cells that are achieved through simultaneous silencing of ACSL4 and induction of GADD45B expression. Targeting HCC with ACSL4highGADD45Blow expression with aspirin and sorafenib could provide potential synergistic therapeutic benefits.

Vascular smooth muscle cells (VSMCs) in the arterial wall have diverse functions. In pathological states, the interplay between transcripts and microRNAs (miRNAs) leads to phenotypic changes. Understanding the regulatory role of miRNAs and their target genes may reveal how VSMCs modulate the pathogenesis of coronary artery disease. Laser capture microdissection was performed on aortic wall tissues obtained from coronary artery bypass graft patients with and without recent acute myocardial infarction (MI). The mSMRT-qPCR miRNA assay platform (MiRXES, Singapore) was used to profile miRNA. The miRNA data were co-analyzed with significant mRNA transcripts. TargetScan 7.1 was applied to evaluate miRNA–mRNA interactions. The miRNA profiles of 29 patients (16 MI and 13 non-MI) were evaluated. Thirteen VSMC-related miRNAs were differentially expressed between the MI and non-MI groups. Analysis revealed seven miRNA-targeted mRNAs related to muscular tissue differentiation and proliferation. TargetScan revealed that among the VSMC-related transcripts, MBNL1 had a recognition site that matched the hsa-miR-30b-5p target seed sequence. In addition to predicted analysis, our experiment in vitro with human VSMC culture confirmed that hsa-miR-30b-5p negatively correlated with MBNL1. Our data showed that overexpression of hsa-miR-30b-5p led to downregulation of MBNL1 in VSMCs. This process influences VSMC proliferation and might be involved in VSMC differentiation.

There is an increasing urgency in the search for new drugs to target high-grade cancers such as osteosarcomas (OS), as these have limited therapeutic options and poor prognostic outlook. Even though key molecular events leading to tumorigenesis are not well understood, it is widely agreed that OS tumours are Wnt-driven. ETC-159, a PORCN inhibitor that inhibits the extracellular secretion of Wnt, has recently progressed on to clinical trials. In vitro and in vivo murine and chick chorioallantoic membrane xenograft models were established to examine the effect of ETC-159 on OS. Consistent with our hypothesis, we noted that ETC-159 treatment not only resulted in markedly decreased β-catenin staining in xenografts, but also increased tumour necrosis and a significant reduction in vascularity—a hereby yet undescribed phenotype following ETC-159 treatment. Through further understanding the mechanism of this new window of vulnerability, therapies can be developed to potentiate and maximize the effectiveness of ETC-159, further increasing its clinical utility for the treatment of OS.

Aim: To investigate the impact of oxaliplatin resistance on the cellular characteristics and miRNA expression pattern in colorectal cancer cells. Methods: A stable oxaliplatin-resistant colorectal cancer HCT116 cell line was established by exposure to increasing doses of oxaliplatin. Alterations in cytotoxicity, migration, invasion and tumorsphere formation were assessed by MTS assay, modified Boyden chamber assay, and colonosphere assay respectively. The miRNAome of the oxaliplatin-resistant HCT116 cells was analyzed using the TaqMan PCR Human miRNA array. Upregulated miRNAs from the PCR array were validated by real-time reverse transcription-quantitative PCR (RT-qPCR). Results: Oxaliplatin-resistant HCT116 cells exhibited higher migration, invasion and tumorsphere formation compared to parental oxaliplatin-sensitive HCT116 cells. The oxaliplatin-resistant cells showed a distinct miRNA expression profile compared to the parental cells. The expression of miR-601, miR-222, miR-202 and miR-25 were verified by RT-qPCR to be increased in resistant cells. Bioinformatics analyses were used to identify potential target mRNAs of these 4 miRNAs. Conclusion: Results presented in this study provide evidence that oxaliplatin-resistance induces phenotypic changes in colorectal cancer and alterations in miRNA expression. Functional studies on the miRNAs and their target mRNA may enable the discovery of functional pathways to chemoresistance in colorectal cancer.

Introduction: Cancer is thought to represent a breakdown of multicellular cooperation and reversion to Darwinian dynamics characterized principally by self-interested competition. However, there is increasing evidence that cancer cells can behave as communities, manifesting social behaviors that influence cancer progression. Methods: Circulating tumor cells enrichment, microRNA extraction, qRT-PCR, MTS assays, RNA in situ hybridization, immunohistochemical staining, SILAC-based mass spectrometry, flow cytometry, ChIP-sequencing, and western blotting. Results: We report here evidences of altruistic cooperation in clonal breast cancer cells. Heterogeneity in expression of a microRNA, miR-125b, leads to sectoring of clonal breast cancer cell populations into minority miR-125b-high and majority miR-125b-low subpopulations. Enhanced population-wide tolerance to taxane-based chemotherapy is mediated by the miR-125b-high minority, in part through increased secretion of extracellular public goods such as insulin-like growth factor binding protein 2 (IGFBP2) and chemokine (C-C motif) ligand 28 (CCL28). Cost-benefit analysis established this helping behavior to be altruistic, as survival benefits conferred to the miR-125b-low cells, via public goods sharing, occurred at a fitness cost to the miR-125b-high cells. Notwithstanding this fitness cost, miR-125b-high altruists regenerate readily from isolated populations of miR-125b-low defectors, via Kruppel-like factor 2-mediated epigenetic mechanism of histone deacetylation. As therapeutic proof-of-principle, we demonstrated that targeting extracellular IGFBP2 and CCL28, through ligand neutralization, markedly blunted the tolerance response of cancer cells towards taxane chemotherapy. Conclusions: Our results demonstrate how positive social engagement such as altruism may be employed by heterogeneous clonal cancer communities to drive chemotolerance, and understanding of such social behaviors could help formulate more effective treatment strategies. Citation Format: Kee Wah Lee, Muhammad Sufyan Masroni, Karen Meiling Tan, Mo-Huang Li, Lihan Zhou, Steven Tucker, Lynette Su Mien Ngo, Chan Fong Chang, Boon Huat Bay, Soo Yong Tan, Mikael Hartman, Huiwen Chua, Tze Ping Loh, Thomas Putti, Sai Mun Leong, Evelyn Siew-Chuan Koay. Regenerable altruism drives chemotolerance in clonal cancer cells [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 203.