Hyperplasia and impaired involution in the mammary gland of transgenic mice expressing human FGF4

Multimodal integration using a machine learning approach facilitates risk stratification in HR+/HER2- breast cancer

Hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) breast cancer is the most common type of breast cancer, with continuous recurrence remaining an important clinical issue. Current relapse predictive models in HR+/HER2- breast cancer patients still have limitations. The integration of multidimensional data represents a promising alternative for predicting relapse. In this study, we leverage our multi-omics cohort comprising 579 HR+/HER2- breast cancer patients (200 patients with complete data across 7 modalities) and develop a machine-learning-based model, namely CIMPTGV, which integrates clinical information, immunohistochemistry, metabolomics, pathomics, transcriptomics, genomics, and copy number variations to predict recurrence risk of HR+/HER2- breast cancer. This model achieves concordance indices (C-indices) of 0.871 and 0.869 in the train and test sets, respectively. The risk population predicted by the CIMPTGV model encompasses those identified by single-modality models. Feature analysis reveals that synergistic and complementary effects exist in different modalities. Simultaneously, we develop a simplified model with a mean area under the curve (AUC) of 0.840, presenting a useful approach for clinical applications.

A validated genome wide association study to breed cattle adapted to an environment altered by climate change

Continued production of food in areas predicted to be most affected by climate change, such as dairy farming regions of Australia, will be a major challenge in coming decades. Along with rising temperatures and water shortages, scarcity of inputs such as high energy feeds is predicted. With the motivation of selecting cattle adapted to these changing environments, we conducted a genome wide association study to detect DNA markers (single nucleotide polymorphisms) associated with the sensitivity of milk production to environmental conditions. To do this we combined historical milk production and weather records with dense marker genotypes on dairy sires with many daughters milking across a wide range of production environments in Australia. Markers associated with sensitivity of milk production to feeding level and sensitivity of milk production to temperature humidity index on chromosome nine and twenty nine respectively were validated in two independent populations, one a different breed of cattle. As the extent of linkage disequilibrium across cattle breeds is limited, the underlying causative mutations have been mapped to a small genomic interval containing two promising candidate genes. The validated marker panels we have reported here will aid selection for high milk production under anticipated climate change scenarios, for example selection of sires whose daughters will be most productive at low levels of feeding.

Mammary involution and breast cancer risk: transgenic models and clinical studies

Postlactational involution is the process following weaning during which the mammary gland undergoes massive cell death and tissue remodeling as it returns to the pre-pregnant state. Lobular involution is the process by which the breast epithelial tissue is gradually lost with aging of the mammary gland. While postlactational involution and lobular involution are distinct processes, recent studies have indicated that both are related to breast cancer development. Experiments using a variety of rodent models, as well as observations in human populations, suggest that deregulation of postlactational involution may act to facilitate tumor formation. By contrast, new human studies show that completion of lobular involution protects against subsequent breast cancer incidence.

Ultrastructural Morphometry of Mammary Gland in Transgenic and Non-transgenic Rabbits

The mammary gland of transgenic animals has been used for the production of recombinant proteins of therapeutic and nutraceutical use. The objective of this study was to compare the ultrastructure of transgenic and non-transgenic rabbit mammary gland tissue. New Zealand White transgenic rabbits were obtained by breeding non-transgenic rabbits with transgenic founder rabbits containing a whey acidic protein-human factor VIII (WAP-hFVIII) transgene integrated into their genome. Samples of mammary gland tissue from lactating rabbit females were isolated by surgical procedures. These samples were examined by optical and electron microscopy and photographs were taken. Measurements of ultrastructural organelles were made from digital images of the mammary cells. No differences were found in the cellular structure of mammary tissue, but significant differences t((0.001)) in the relative volume of mitochondria and vacuoles between transgenic and non-transgenic mammary gland epithelium were observed.

FGF9 promotes survival of germ cells in the fetal testis

In addition to its role in somatic cell development in the testis, our data have revealed a role for Fgf9 in XY germ cell survival. In Fgf9-null mice, germ cells in the XY gonad decline in numbers after 11.5 days post coitum (dpc), while germ cell numbers in XX gonads are unaffected. We present evidence that germ cells resident in the XY gonad become dependent on FGF9 signaling between 10.5 dpc and 11.5 dpc, and that FGF9 directly promotes XY gonocyte survival after 11.5 dpc, independently from Sertoli cell differentiation. Furthermore, XY Fgf9-null gonads undergo true male-to-female sex reversal as they initiate but fail to maintain the male pathway and subsequently express markers of ovarian differentiation(Fst and Bmp2). By 14.5 dpc, these gonads contain germ cells that enter meiosis synchronously with ovarian gonocytes. FGF9 is necessary for 11.5 dpc XY gonocyte survival and is the earliest reported factor with a sex-specific role in regulating germ cell survival.

Point mutation in AML1 disrupts subnuclear targeting, prevents myeloid differentiation, and effects a transformation-like phenotype

The multifunctional C terminus of the hematopoietic AML1 transcription factor interacts with coregulatory proteins, supports the convergence and integration of physiological signals, and contains the nuclear matrix targeting signal, the protein motif that is necessary and sufficient to target AML1 to subnuclear sites. The (8;21) chromosomal translocation, which replaces the C terminus of AML1 with the ETO protein, modifies subnuclear targeting of AML1 in acute myeloid leukemia (AML) and results in defective myelopoiesis. We therefore addressed the relevance of AML1 subnuclear targeting and associated functions that reside in the C terminus to myeloid differentiation. A single amino acid substitution that abrogates intranuclear localization was introduced in the AML1 subnuclear targeting signal. Expression of the mutant AML1 protein blocks differentiation of myeloid progenitors to granulocytes in the presence of endogenous AML1 protein, as also occurs in the (8;21) chromosomal translocation, where only one allele of the AML1 gene is affected. The cells expressing the mutant AML1 protein continue to proliferate, maintain an immature blast-like morphology, and exhibit transformed properties that are hallmarks of leukemogenesis. These findings functionally link AML1 subnuclear targeting with competency for myeloid differentiation and expression of the transformed/leukemia phenotype.

Chromosome aberrations in solid tumors

Chromosome aberrations in human solid tumors are hallmarks of gene deregulation and genome instability. This review summarizes current knowledge regarding aberrations, discusses their functional importance, suggests mechanisms by which aberrations may form during cancer progression and provides examples of clinical advances that have come from studies of chromosome aberrations.

Inhibition of ductal morphogenesis in the mammary gland of WAP -fgf4 transgenic mice

We previously demonstrated that expression of human FGF4 in the epithelial compartment of murine mammary glands caused hyperplasia during lactation and a dramatic delay in gland involution due to inhibition of cellular apoptosis. We now analyse the effects of transgene expression during development of the organ. Expression of WAP- Fgf4 initiate with the onset of sexual hormones (4 weeks of age), and defects in morphogenesis of the organ were already apparent at 5 weeks of age and persisted throughout all stages of post-natal development. These defects involved ductal development, but not lobuloalveolar morphogenesis, and were due to a decrease in the level of apoptosis within the terminal end buds. We also show that regulation of apoptosis by FGF4 in the mammary gland, both during development and involution, could occur via inhibition of Bcl2 expression. Overall our data demonstrate that FGF4 is a regulator of mammary epithelial cells apoptosis during all stages in which programmed cell death is an important mechanism of development, namely morphogenesis and involution. We also suggest that this growth factor could act by interfering with the Bcl2 pathway.