No abstract

Sarcomas are rare but malignant tumors with high risks of local recurrence and distant metastasis. Anti-angiogenic therapy is a potential strategy against un-controlled and not-organized tumor angiogenesis. We aimed to assess the safety and efficacy of apatinib, an oral tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor-2, in patients with advanced sarcoma. Thirty-one patients who received initial apatinib between September 2015 and August 2016 were retrospectively reviewed. Among them, 19 (61.3%) patients were heavily pretreated with two or more lines of cytotoxic chemotherapy. Apatinib was given at a start-dose of 425 mg qd. During therapy, 9 (29.0%) patients required dose interruption and 7 (22.6%) needed dose reduction, and the mean dosage of apatinib was 372.9 ± 68.4 mg/day. In the study cohort, one patient was treated as adjunctive therapy and 6 patients stopped treatment before radiographic response assessment. Thus, 24 patients were eligible for tumor response evaluation. The objective response rate was 33.3% and clinical benefit rate was as high as 75.0%. The progression free survival was 4.25 (95% confidence interval [CI], 2.22-5.11) months, whereas the overall survival was 9.43 (95% CI, 6.64-18.72) months. Compared with other histological subtypes, leiomyosarcoma did not show significant survival benefits. Most of the adverse events (AEs) were at grade 1 or 2. The main grade 3 AEs were hypertension (6.5%), hand foot skin reaction (6.5%), and diarrhea (3.2%). In conclusion, apatinib showed promising efficacy and acceptable safety profile in metastatic or recurrent sarcoma, giving rationale clinical evidence to conduct clinical trials.

Machado-Joseph disease (MJD) is caused by a (CAG)n trinucleotide repeat expansion that is translated into an abnormally long polyglutamine tract. This disease is considered the most common form of spinocerebellar ataxia (SCA). In the present study, we developed stable inducible cell lines (PC12Tet-On-Ataxin-3-Q28/84) expressing ataxin-3 with either normal or abnormal CAG repeats under doxycycline control. The expression of acetyl histone H3 and the induction of c-Fos in response to cAMP were strongly suppressed in cells expressing the protein with the expanded polyglutamine tract. Treatment with valproic acid, a histone deacetylase inhibitor (HDACi), attenuated mutant ataxin-3-induced cell toxicity and suppression of acetyl histone H3, phosphorylated cAMP-responsive element binding protein (p-CREB) as well as c-Fos expression. These results indicate that VPA can stimulate the up-regulation of gene transcription through hyperacetylation. Thus, VPA might have a therapeutic effect on MJD.

Human epidermal growth factor receptor 2 (HER2/erbB2) is a key driver and therapeutic target for breast cancer. The treatment of HER2‐positive breast cancer remains a clinical challenge largely due to the limited understanding of HER2‐driving oncogenic signaling and the frequent resistance to simply HER2‐targeted therapy. Here, we show that the histone deacetylase inhibitor, trichostatin A (TSA), suppresses HER2‐overexpressing breast cancer via upregulation of miR‐146a and the resultant repression of its oncogenic targets, interleukin‐1 receptor‐associated kinase 1 and the chemokine receptor CXCR4. Mechanistically, histone H3K56 acetylation and deacetylation on the MIR146A promoter are catalyzed respectively by the acetyltransferase p300 and histone deacetylase 1 (HDAC1), both of which are recruited to the genomic loci by the transcription factor specificity protein 1 (Sp1). HER2 signaling phosphorylates Sp1 and induces its predominant association with HDAC1, but not p300, leading to histone hypoacetylation and silencing of MIR146A. In addition, the death receptor Fas is similarly downregulated by the aforementioned epigenetic paradigm, indicating its wide involvement in impairing tumor suppressor gene expression. Consequently, TSA synergizes with lapatinib, a tyrosine kinase inhibitor of HER2, to suppress breast cancer in vitro and in rodent models. These findings demonstrate a novel mechanism of HER2‐driven carcinogenesis and suggest the applicability of combined HER2 and HDAC targeting in breast cancer therapy.