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Hematopoietic PBX‐interacting protein (HPIP, also known as PBXIP1) is an estrogen receptor (ER) interacting protein that regulates estrogen‐mediated breast cancer cell proliferation and tumorigenesis. However, its functional significance in the context of mammary gland development is unexplored. Here, we report that HPIP is required for prolactin (PRL)‐induced lactogenic differentiation in vitro. Molecular analysis of HPIP expression in mice revealed its induced expression at pregnancy and lactation stages of mammary gland. Moreover, PRL is a lactogenic hormone that controls pregnancy as well as lactation and induces Hpip/Pbxip1 expression in a signal transducer and activator of transcription 5a‐dependent manner. Using mammary epithelial and lactogenic‐competent cell lines, we further show that HPIP plays a regulatory role in PRL‐mediated mammary epithelial cell differentiation, which is measured by acini formation, β‐casein synthesis, and lipid droplet formation. Further mechanistic studies using pharmacological inhibitors revealed that HPIP modulates PRL‐induced β‐casein synthesis via phosphoinositide 3‐kinase (PI3K)/protein kinase B (AKT) activation. This study also identified HPIP as a critical regulator of autocrine PRL signaling as treatment with the PRL receptor antagonist Δ1‐9‐G129R‐hPRL restrained HPIP‐mediated PRL synthesis, AKT activation, and β‐casein synthesis in cultured HC11 cells. Interestingly, we also uncovered that microRNA‐148a (miR‐148a) antagonizes HPIP‐mediated mammary epithelial cell differentiation. Together, our study identified HPIP as a critical regulator of PRL signaling and revealed a novel molecular circuitry involving PRL, HPIP, PI3K/AKT, and miR‐148a that controls mammary epithelial cell differentiation in vitro. [ABSTRACT FROM AUTHOR]

Calcium silicate ceramics have received significant attention for biomedical applications for their excellent bioactivity and osteoconduction properties. Sol‐gel process is extensively used for the fabrication of calcium silicates. In sol‐gel process, calcium nitrate tetra hydrate (Ca(NO3)2·4H2O) and tetraethylorthosilicate (TEOS) are used as precursors. However, these precursors are expensive. The objective of this work was to compare in vitro behavior of calcium silicate (CaSiO3) produced using biowaste such as rice husk ash (RHA) and eggshells (coded; NCS) with CaSiO3 prepared using TEOS and Ca(NO3)2·4H2O (coded; CCS). Thermal investigation results revealed that the crystallization temperature for NCS is relatively lower (772°C) than for CCS (870°C). Bioactivity was studied in vitro using simulated body fluid (SBF) with respect to mineralization rate of hydroxyapatite. Mineralization of a greater hydroxyapatite was observed on NCS ceramics than CCS ceramics after incubation for 3, 7, 14 days in SBF solution, which was confirmed using X‐ray diffractometer, Fourier transform infrared spectroscopy, scanning electron microscopy‐energy dispersive spectroscopy. Degradation studies were conducted in Tris‐HCl solution and the test results revealed that NCS ceramics has lower dissolution rate than CCS ceramics. The antimicrobial assay has shown that NCS samples exhibit significant zone of inhibition against Escherichia coli and Staphylococcus aureus which confirmed that the CaSiO3 prepared from RHA and eggshell can prevent bacteria from adhering to the surface. In addition cell culture studies revealed that NCS ceramics possess good cytocompatibility with MG‐63 cells and significantly promoted cell proliferation. [ABSTRACT FROM AUTHOR]