Overexpression of UHRF1 and its potential role in the development of invasive ductal breast cancer validated by integrative bioinformatics and immunohistochemistry analyses

Efficacy of sentinel lymph-node biopsy after neoadjuvant chemotherapy in clinically axilla node-negative patients

PURPOSE

Breast cancer is the most common cancer in women. Developments in breast cancer treatment have extended the life expectancy of these patients, raising the issue of morbidity of breast cancer surgery, the major cause of which is axillary dissection. The aim of the present study was to establish the safety of sentinel node biopsy (SLNB) in patients with a clinically node-negative axilla after neoadjuvant chemotherapy (NACT).

METHODS

We recorded demographic data, as well as the findings of physical examination, imaging, and pathology before and after NACT. SLNB with indocyanine green + isosulfan blue and axillary dissection were performed and the surgical and pathology findings were recorded.

RESULTS

A sentinel lymph node was detected in 80 of 90 patients who underwent surgery. When ≥ three sentinel lymph nodes were removed as negative in the patient group with cN0 after treatment, we evaluated the axilla as being negative with an accuracy of 100%.

CONCLUSIONS

Axillary lymph-node dissection may not be necessary for patients with cNO confirmed by physical and radiological examination using positron emission tomography (PET) computed tomography (CT), and breast magnetic resonance imaging (MRI) after NACT, if ≥ three negative SLNB are removed. Further studies are needed to confirm our findings.

Novel strategy for activating gene expression through triplex DNA formation targeting epigenetically suppressed genes

Triplex DNA formation is a useful genomic targeting tool that is expected to have a wide range of applications, including the antigene method; however, there are fundamental limitations in its forming sequence. We recently extended the triplex DNA-forming sequence to methylated DNA sequences containing 5mCG base pairs by developing guanidino-dN, which is capable of recognizing a 5mCG base pair with high affinity. We herein investigated the effect of triplex DNA formation using TFOs with guanidino-dN on methylated DNA sequences at the promoter of the RASSF1A gene, whose expression is epigenetically suppressed by DNA methylation in MCF-7 cells, on gene expression. Interestingly, triplex DNA formation increased the expression of the RASSF1A gene at the transcript and protein levels. Furthermore, RASSF1A-activated MCF-7 cells exhibited cell growth suppressing activity. Changes in the expression of various genes associated with the promotion of apoptosis and breast cancer survival accompanied the activation of RASSF1A in cells exhibited antiproliferative activity. These results suggest the potential of increases in gene expression through triplex DNA formation as a new genomic targeting tool.

Novel UHRF1-MYC Axis in Acute Lymphoblastic Leukemia

Ubiquitin-like, containing PHD and RING finger domain, (UHRF) family members are overexpressed putative oncogenes in several cancer types. We evaluated the protein abundance of UHRF family members in acute leukemia. A marked overexpression of UHRF1 protein was observed in ALL compared with AML. An analysis of human leukemia transcriptomic datasets revealed concordant overexpression of UHRF1 in B-Cell and T-Cell ALL compared with CLL, AML, and CML. In-vitro studies demonstrated reduced cell viability with siRNA-mediated knockdown of UHRF1 in both B-ALL and T-ALL, associated with reduced c-Myc protein expression. Mechanistic studies indicated that UHRF1 directly interacts with c-Myc, enabling ALL expansion via the CDK4/6-phosphoRb axis. Our findings highlight a previously unknown role of UHRF1 in regulating c-Myc protein expression and implicate UHRF1 as a potential therapeutic target in ALL.

Molecular basis of hUHRF1 allosteric activation for synergistic histone modification binding by PI5P

Chromatin marks are recognized by distinct binding modules, many of which are embedded in multidomain proteins. How the different functionalities of such complex chromatin modulators are regulated is often unclear. Here, we delineated the interplay of the H3 amino terminus- and K9me-binding activities of the multidomain hUHRF1 protein. We show that the phosphoinositide PI5P interacts simultaneously with two distant flexible linker regions connecting distinct domains of hUHRF1. The binding is dependent on both, the polar head group, and the acyl part of the phospholipid and induces a conformational rearrangement juxtaposing the H3 amino terminus and K9me3 recognition modules of the protein. In consequence, the two features of the H3 tail are bound in a multivalent, synergistic manner. Our work highlights a previously unidentified molecular function for PI5P outside of the context of lipid mono- or bilayers and establishes a molecular paradigm for the allosteric regulation of complex, multidomain chromatin modulators by small cellular molecules.