Project description:Purpose: In an HIV cure setting, Vorinostat may provide the “shock” capable of flushing HIV out of the persistent reservoir, while antiretroviral therapy is used to prevent new infections. However, this drug may modulate the expression of human endogenous retroviruses (HERVs). This study demonstrates significant modulation of HERVs and suggests that they should be considered as off-target effects of this drug treatment. Methods: Peripheral blood mononuclear cells were collected from 4 healthy donors. Naive CD4 T cells were isolated and utilized to assess HERV dysregulation after treatment with Vorinostat. Cells were collected for study and exposed to a dose of Vorinostat (10uM dose over a 24 hour period). After this, RNA was extracted from cells and their untreated paired counterparts for deep sequencing by Expression Analysis. Sequence reads that passed quality filters were mapped to the HERVd reference database using Bowtie and counted using HTSeq. Any HERV which did not achieve at least 1 count per million mapped and counted reads in at least 4 samples was discarded. Differential expression was performed upon the filtered dataset with edgeR and using TMM normalization. Results: Using an custom built data analysis pipeline, ~100 million reads per sample were mapped to the HERVd reference database and identified 10784 distinct dysregulated elements Bowtie/HTSeq workflow. Differential expression analysis was performed between vorinostat treated and untreated conditions which demonstrated 2102 dysregulated HERV elements with 1007 downregulated and 1095 upregulated (FDR < 0.05) with EdgeR. Results were further subset with a log2FC ± 3 which resulted in 451 upregulated and 363 downregulated HERV elements from 81 and 82 distinct families respectively. HERV elements from the LTR12 family were by far the most dramatically upregulated in family frequency and fold change magnitude. Further confirmation with droplet digital PCR confirmed upregulation of LTR12 elements and demonstrated an exponential dose response curve with HERV expression found at even moderate doses (334nM) of vorinostat treatment. Conclusions: This study represents the first detailed analysis of HERV dysregulation following vorinostat treatment using the untargeted approach of total RNA-Seq. These results demonstrate that vorinostat dysregulates multiple HERV families with a propensity to upregulate members of the LTR12 HERV family. This study also provides a methodology to analyze HERV dysregulation in future treatments with vorinostat or other drugs by providing a mechanism to choose primer and probe sets which will properly represent HERV dysregulation as expression across an HERV is not uniform or continuous. Finally, this work suggests that HERV dysregulation by vorinostat treatment should be considered an off-target effect of this drug and HERV elements, such as LTR12, should be monitored as biomarkers during shock and kill clinical trials with HDAC inhibitors and that trial subjects should be screened to explore further HIV:HERV interactions.

Project description:Gene Expression Profiling of a Mouse Xenograft Model of â??Triple-Negativeâ?? Breast Cancer Brain Metastases With and Without Vorinostat Treatment. Purpose: As chemotherapy and molecular therapy improve the systemic survival of breast cancer patients, the incidence of brain metastases increases. Few therapeutic strategies exist for the treatment of brain metastases because the blood-brain barrier severely limits drug access. We report the pharmacokinetic, efficacy, and mechanism of action studies for the histone deactylase inhibitor vorinostat (suberoylanilide hydroxamic acid) in a preclinical model of brain metastasis of triple-negative breast cancer. Experimental Design: The 231-BR brain trophic subline of the MDA-MB-231 human breast cancer cell line was injected into immunocompromised mice for pharmacokinetic and metastasis studies. Pharmacodynamic studies compared histone acetylation, apoptosis, proliferation, and DNA damage in vitro and in vivo. Results: Following systemic administration, uptake of [14C]vorinostat was significant into normal rodent brain and accumulation was up to 3-fold higher in a proportion of metastases formed by 231-BR cells. Vorinostat prevented the development of 231-BR micrometastases by 28% (P = 0.017) and large metastases by 62% (P < 0.0001) compared with vehicle-treated mice when treatment was initiated on day 3 post-injection. The inhibitory activity of vorinostat as a single agent was linked to a novel function in vivo: induction of DNA double-strand breaks associated with the down-regulation of the DNA repair gene Rad52. Conclusions: We report the first preclinical data for the prevention of brain metastasis of triple-negative breast cancer. Vorinostat is brain permeable and can prevent the formation of brain metastases by 62%. Its mechanism of action involves the induction of DNA double-strand breaks, suggesting rational combinations with DNA active drugs or radiation. Experiment Overall Design: We performed gene expression profiling on metastases from vehicle- or vorinostat-treated mice to determine if alterations in gene expression were observable that were consistent with the phenotypes observed. Brain metastases from five vehicle-treated mice and six 150 mg/kg vorinostat-treated mice were procured by laser capture microdissection. RNA was extracted from the captured tumor cells from each brain and two rounds of linear amplification was done. The amplified RNA from each mouse was processed separately through microarray hybridization and analysis.

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Vorinostat treatment of PPS-ICBR cells

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