Hemophilia A ameliorated in mice by CRISPR-based in vivo genome editing of human Factor VIII

Hemophilia A is a monogenic disease with a blood clotting factor VIII (FVIII) deficiency caused by mutation in the factor VIII (F8) gene. Current and emerging treatments such as FVIII protein injection and gene therapies via AAV-delivered F8 transgene in an episome are costly and nonpermanent. Here, we describe a CRISPR/Cas9-based in vivo genome editing method, combined with non-homologous end joining, enabling permanent chromosomal integration of a modified human B domain deleted-F8 (BDD-F8) at the albumin (Alb) locus in liver cells. To test the approach in mice, C57BL/6 mice received tail vein injections of two vectors, AAV8-SaCas9-gRNA, targeting Alb intron 13, and AAV8-BDD-F8. This resulted in BDD-F8 insertion at the Alb locus and FVIII protein expression in the liver of vector-, but not vehicle-, treated mice. Using this approach in hemophilic mice, BDD-F8 was expressed in liver cells as functional human FVIII, leading to increased plasma levels of FVIII and restoration of blood clotting properties in a dose-dependent manor for at least 7 months, with no detectable liver toxicity or meaningful off-target effects. Based on these findings, our BDD-F8 genome editing approach may offer an efficacious, long-term and safe treatment for patients with hemophilia A.

Early diagnosis of gestational diabetes mellitus using circulating microRNAs

DESIGN

Gestational diabetes mellitus (GDM) is one of the most common pregnancy complications and its prevalence is constantly rising worldwide. Diagnosis is commonly in the late second or early third trimester of pregnancy, though the development of GDM starts early; hence, first-trimester diagnosis is feasible.

OBJECTIVE

Our objective was to identify microRNAs that best distinguish GDM samples from those of healthy pregnant women and to evaluate the predictive value of microRNAs for GDM detection in the first trimester.

METHODS

We investigated the abundance of circulating microRNAs in the plasma of pregnant women in their first trimester. Two populations were included in the study to enable population-specific as well as cross-population inspection of expression profiles. Each microRNA was tested for differential expression in GDM vs control samples, and their efficiency for GDM detection was evaluated using machine-learning models.

RESULTS

Two upregulated microRNAs (miR-223 and miR-23a) were identified in GDM vs the control set, and validated on a new cohort of women. Using both microRNAs in a logistic-regression model, we achieved an AUC value of 0.91. We further demonstrated the overall predictive value of microRNAs using several types of multivariable machine-learning models that included the entire set of expressed microRNAs. All models achieved high accuracy when applied on the dataset (mean AUC = 0.77). The significance of the classification results was established via permutation tests.

CONCLUSIONS

Our findings suggest that circulating microRNAs are potential biomarkers for GDM in the first trimester. This warrants further examination and lays the foundation for producing a novel early non-invasive diagnostic tool for GDM.

MicroRNA regulation of progesterone receptor in breast cancer

Hormone receptor status is of significant value when deciding on anti-estrogenic adjuvant therapy for breast cancer tumors. However, while estrogen receptor (ER) regulation was intensively studied, the regulation of progesterone receptor (PR) levels has not been extensively investigated. MicroRNAs (miRNAs, miRs) are post-transcriptional negative regulators of gene expression involved in diverse cellular processes. The aim of this study was to identify miRNAs that regulate PR in breast cancer.We mapped potential miRNA binding sites for miR-181a, miR-23a and miR-26b on PR mRNA and demonstrated a direct regulation of PR by these three miRNAs by in-vitro Luciferase binding assays. Over-expression of each miRNA in MCF-7 cells resulted in a reduction in the expression levels of PR mRNA. Then, expression levels of these miRNAs were measured in Formalin-Fixed, Paraffin-Embedded (FFPE) samples of 29 ER-positive breast cancer tumors and adjacent normal breast tissues. A significant reciprocal correlation between PR mRNA and the miRNA levels were identified suggesting a role for miR-181a, miR-23a and miR-26b in PR regulation in breast cancer. Moreover, the average expression fold-changes of the three miRNAs between cancerous and normal tissues displayed an opposite trend when analyzing according to Immuno-histochemistry(IHC) status. Furthermore, miR-181a and miR-26b were found to be over-expressed in most tumor tissues supporting their role in ER-positive breast cancer development. We conclude that miR-181a, miR-23a and miR-26b act as negative regulators of PR expression in ER-positive breast cancer. The diagnostic and prognostic potential of these miRNAs in breast cancer should be further evaluated.

Local microRNA delivery targets Palladin and prevents metastatic breast cancer

Metastasis is the primary cause for mortality in breast cancer. MicroRNAs, gene expression master regulators, constitute an attractive candidate to control metastasis. Here we show that breast cancer metastasis can be prevented by miR-96 or miR-182 treatment, and decipher the mechanism of action. We found that miR-96/miR-182 downregulate Palladin protein levels, thereby reducing breast cancer cell migration and invasion. A common SNP, rs1071738, at the miR-96/miR-182-binding site within the Palladin 3'-UTR abolishes miRNA:mRNA binding, thus diminishing Palladin regulation by these miRNAs. Regulation is successfully restored by applying complimentary miRNAs. A hydrogel-embedded, gold-nanoparticle-based delivery vehicle provides efficient local, selective, and sustained release of miR-96/miR-182, markedly suppressing metastasis in a breast cancer mouse model. Combined delivery of the miRNAs with a chemotherapy drug, cisplatin, enables significant primary tumour shrinkage and metastasis prevention. Our data corroborate the role of miRNAs in metastasis, and suggest miR-96/miR-182 delivery as a potential anti-metastatic drug.

Involvement of microRNA in the regulation of progesterone receptor in breast cancer

578

Background: The progesterone receptor (PgR) is a prognostic factor in ER positive breast cancers treated by adjuvant hormonal treatment. While PgR protein is usually assessed by immunohistochemistry (IHC), RT-PCR measurement of mRNA levels is provided by Oncotype Dx and other tests. Between 20-40% of tumors are discrepant in IHC and RT-PCR PgR expression, reflecting either technical problems or biological mechanisms. MicroRNAs regulate gene expression either at the mRNA or the protein translation level. Our hypothesis is that the latter potentially explains discrepancies between IHC and RT-PCR results. Methods: ER positive tumors were divided to three groups by PgR expression according to IHC and RT-PCR: (i) positive by IHC; (ii) negative by IHC and high mRNA levels by RT-PCR; (iii) negative by IHC and low mRNA levels by RT-PCR. RNA was extracted from tumors and adjacent normal tissue and the expression of PgR and microRNAs was assessed by RT-PCR. In addition, microRNAs were transfected into MCF-7 cells. The levels of PgR mRNA and protein were analyzed. Results: The PgR gene contains potential conserved binding sites for MicroRNAs 23a, 181a, 135a and 26b. Of these, miR- 23a and miR-181a showed inverse expression relative to the PgR expression in normal and tumor tissue, as expected. MicroRNA levels were determined in tumors of all three groups. The highest expression of microRNAs 23a, 181a and 26b was seen in IHC negative tumors with low levels of mRNA. Intermediate expression was seen in IHC negative tumors with high mRNA levels, and the lowest expression was detected in IHC positive tumors. Preliminary results suggest that over expression of microRNAs 23a, 181a and 26b in MCF7 cells decreased PgR levels. Conclusions: Our results suggest that microRNAs 23a , 181a and 26b regulate the level of the progesterone receptor in breast cancer and that tumors with relatively high mRNA levels may be deficient in PgR protein due to downregulation by microRNAs. [Table: see text]