The immunomodulatory protein B7-H4 is overexpressed in breast and ovarian cancers and promotes epithelial cell transformation

B7-H4 protein is expressed on the surface of a variety of immune cells and functions as a negative regulator of T cell responses. We independently identified B7-H4 (DD-O110) through a genomic effort to discover genes upregulated in tumors and here we describe a new functional role for B7-H4 protein in cancer. We show that B7-H4 mRNA and protein are overexpressed in human serous ovarian cancers and breast cancers with relatively little or no expression in normal tissues. B7-H4 protein is extensively glycosylated and displayed on the surface of tumor cells and we provide the first demonstration of a direct role for B7-H4 in promoting malignant transformation of epithelial cells. Overexpression of B7-H4 in a human ovarian cancer cell line with little endogenous B7-H4 expression increased tumor formation in SCID mice. Whereas overexpression of B7-H4 protected epithelial cells from anoikis, siRNA-mediated knockdown of B7-H4 mRNA and protein expression in a breast cancer cell line increased caspase activity and apoptosis. The restricted normal tissue distribution of B7-H4, its overexpression in a majority of breast and ovarian cancers and functional activity in transformation validate this cell surface protein as a new target for therapeutic intervention. A therapeutic antibody strategy aimed at B7-H4 could offer an exciting opportunity to inhibit the growth and progression of human ovarian and breast cancers.     

Kallikrein-related peptidases in prostate, breast, and ovarian cancers: from pathobiology to clinical relevance

Tissue kallikrein (KLK1) and kallikrein-related peptidases (KLK2-15) comprise a family of 15 highly conserved secreted serine proteases with similar structural characteristics and a wide spectrum of functional properties. Both gene expression and protein activity of KLKs are rigorously controlled at various levels via diverse mechanisms, including extensive steroid hormone regulation, to exert their broad physiological role. Nevertheless, deregulated expression, secretion, and function of KLK family members has been observed in several pathological conditions and, particularly, in endocrine-related human malignancies, including those of the prostate, breast, and ovary. The cancer-related abnormal activity of KLKs upon substrates such as growth factors, cell adhesion molecules, cell surface receptors, and extracellular matrix proteins facilitate both tumorigenesis and disease progression to the advanced stages. The well-documented relationship between KLK status and the clinical outcome of cancer patients has led to their identification as promising diagnostic, prognostic, and treatment response monitoring biomarkers for these complex disease entities. The main objective of this review is to summarize the existing knowledge concerning the role of KLKs in prostate, breast, and ovarian cancers and to highlight their continually evolving biomarker capabilities that can provide significant benefits for the management of cancer patients.     

Estrogens in the causation of breast, endometrial and ovarian cancers - evidence and hypotheses from epidemiological findings

Estrogens along with progesterone/progestins, and other hormones, are important determinants of cancer in the breast, endometrium and ovary. Estrogens may increase the risk of breast cancer through various mechanisms and at various phases of life, with a possible synergistic effect of progesterone/progestins. Exposure to high doses of placental hormones, such as estrogens and/or progesterone, during pregnancy may play a pivotal role in reducing subsequent breast cancer susceptibility. Estrogens cause endometrial cancer, an effect that can be reduced, prevented or reversed by progesterone/progestin — if allowed to act for a sufficiently long period of each cycle. The role of sex hormones seems important for ovarian carcinogenesis. Intake of combined oral contraceptives has a substantial and well-documented protective effect on endometrial and ovarian cancer risks. Epidemiological observations and experimental data from an animal model indicate that estrogens may have an adverse effect, while progesterone/progestins have a risk reducing effect directly on the ovarian epithelium. Thus, estrogens and other sex hormones have potential effects on the three most important female cancers. Research has yet to define how some of the risk factors can be modified or treatment regimens can be improved to reduce these cancer risks.     

A prospective, randomised, controlled clinical study on the assessment of tolerability and of clinical efficacy of Merional (hMG-IBSA) administered subcutaneously versus Merional administered intramuscularly in women undergoing multifollicular ovarian stimulation in an ART programme (IVF)

Background  

Multifollicular ovarian stimulation (MOS) is widely used in IVF and the compliance to treatment is deeply influenced by the tolerability of the medication(s) used and by the ease of self-administration. This prospective, controlled, randomised, parallel group open label, multicenter, phase III, equivalence study has been aimed to compare the clinical effectiveness (in terms of oocytes obtained) and tolerability of subcutaneous (s.c.) self-administered versus classical intramuscular (i.m.) injections of Merional, a new highly-purified hMG preparation.     

Incorporation of a GnRH agonist,leuprolide acetate,into regimens with exogenous gonadotropins to produce ovarian stimulation and ovulation in the nonpregnant squirrel monkey

This study was designed to measure the effects of variations in the length of pretreatment with a GnRH agonist, leuprolide acetate (LA), on subsequent follicular development and ovulation. The hypothesis was that the duration of LA suppression of pituitary function does not adversely affect ovarian response to standardized ovulation induction protocols in squirrel monkeys. The first phase determined the dose and duration of LA needed to achieve a hypogonadal state. One of two groups received daily subcutaneous injections of 50 μg of LA. The other received a single injection of 175 μg of a depot suspension of LA. Sera were assayed for estradiol (E2) and progesterone (P). E2 and P levels increased 2‐ to 5‐fold with peak levels on days 4 and 7, respectively. Suppression of steroid levels took 10 to 15 days in the LA‐treated group. Depot‐LA did not effectively suppress steroid production. After suppression, females receiving daily LA received five daily injections of hMG to stimulate follicular development. E2 and P increased in these animals. These results suggest that cycling squirrel monkeys have P‐secreting capacity throughout the cycle. This may explain how the squirrel monkey is able to accommodate both a short (4–5 day) luteal phase of their 9 day cycle and implantation from 5 to 7 days after ovulation. A second study compared exogenous follicle stimulating hormone (FSH) to endogenous gonadotropins released as a response to LA in ovulation induction. Steroid production and hCG‐induced ovulation were assessed. LA treatment was compared to a standard ovulation induction protocol by using a randomized cross‐over measures design. There were no differences in E2 and P levels in response to dosages of either LA or hMG. The ovulatory response following LA treatment was not significantly greater than that using FSH. The number of animals with unovulated, large follicles was greater on the FSH protocol (12/18) compared to the LA protocol (3/18). Thus, a single injection of a depot preparation of LA is sufficient to stimulate follicular development and ovulation when followed by an hCG injection. Based on this observation and the data on unovulated large follicles, it is suggested that the ovary responds more readily to endogenous gonadotropins released by LA than to exogenous FSH. Am. J. Primatol. 49:153–164, 1999. © 1999 Wiley‐Liss, Inc.     

Analysis of 17β-hydroxysteroid dehydrogenase types 5, 7, and 12 genetic sequence variants in breast cancer cases from French Canadian Families with high risk of breast and ovarian cancer

A family history and estrogen exposure are well-known risk factors for breast cancer. Members of the 17β-hydroxysteroid dehydrogenase family are responsible for important steps in the metabolism of androgens and estrogens in peripheral tissues, including the mammary gland. The crucial biological function of 17β-HSDs renders these genes good candidates for being involved in breast cancer etiology. This study screened for mutations in HSD17B7 and HSD17B12 genes, which encode enzymes involved in estradiol biosynthesis and in AKR1C3, which codes for 17β-HSD type 5 enzyme involved in androgen and progesterone metabolism, to assess whether high penetrance allelic variants in these genes could be involved in breast cancer susceptibility. Mutation screening of 50 breast cancer cases from non-BRCA1/2 high-risk French Canadian families failed to identify germline likely high-risk mutations in HSD17B7, HSD17B12 and AKR1C3 genes. However, 107 sequence variants were identified, including seven missense variants. Assessment of the impact of missense variants on enzymatic activity of the corresponding enzymes revealed no difference in catalytic properties between variants of 17β-HSD types 7 and 12 and wild-type enzymes, while variants p.Glu77Gly and p.Lys183Arg in 17β-HSD type 5 showed a slightly decreased activity. Finally, a haplotype-based approach was used to determine tagging SNPs providing valuable information for studies investigating associations of common variants in these genes with breast cancer risk.     

Structural and functional analyses of a novel ig-like cell adhesion molecule, hepaCAM, in the human breast carcinoma MCF7 cells

We have recently identified a novel gene, hepaCAM, in liver that encodes a cell adhesion molecule of the immunoglobulin superfamily. In this study, we examined the characteristics of hepaCAM protein and the relationship between its structure and function, in particular its adhesive properties. The wild-type and the cytoplasmic domain-truncated mutants of hepaCAM were transfected into the human breast carcinoma MCF7 cells, and the physiological and biological properties were assessed. Biochemical analyses revealed that hepaCAM is an N-linked glycoprotein phosphorylated in the cytoplasmic domain and that it forms homodimers through cis-interaction on the cell surface. The subcellular localization of hepaCAM appears density-dependent; in well spread cells, hepaCAM is distributed to cell protrusions, whereas in confluent cells, hepaCAM is predominantly accumulated at the sites of cell-cell contacts on the cell membrane. In polarized cells, hepaCAM is recruited to the lateral and basal membranes, and lacking physical interaction, hepaCAM is shown to co-localize with E-cadherin at the lateral membrane. Cell adhesion and motility assays demonstrated that hepaCAM increased cell spreading on the matrices fibronectin and matrigel, delayed cell detachment, and enhanced wound healing. Furthermore, when the cytoplasmic domain was deleted, hepaCAM mutants did not affect cell surface localization and dimer formation. Cell-matrix adhesion, however, was less significantly increased, and cell motility was almost unchanged when compared with the effect of the wild-type hepaCAM. Taken together, the cytoplasmic domain of hepaCAM is essential to its function on cell-matrix interaction and cell motility.     

Association between single-nucleotide polymorphisms of selected genes involved in the response to DNA damage and risk of colon, head and neck, and breast cancers in a Polish population

Single-nucleotide polymorphisms in genes involved in DNA-damage-induced responses are reported frequently to be a risk factor in various cancer types. Here we analysed polymorphisms in 5 genes involved in DNA repair (XPD Asp312Asn and Lys751Gln,XRCC1 Arg399Gln,APE1 Asp148Glu,NBS1 Glu185Gln, andXPA G-4A) and in a gene involved in regulation of the cell-cycle (CCND1 A870G). We compared their frequencies in groups of colon, head and neck, and breast cancer patients, and 2 healthy control groups: (1) matched healthy Polish individuals and (2) a NCBI database control group. Highly significant differences in the distribution of genotypes of theAPE1, XRCC1 andCCND1 genes were found between colon cancer patients and healthy individuals. The 148AspAPE1 allele and the 399GlnXRCC1 allele apparently increased the risk of colon cancer (OR=1.9–2.3 and OR=1.5–2.1, respectively). Additionally, frequencies ofXPD genotypes differed between healthy controls and patients with colon or head and neck cancer. Importantly, no differences in the distribution of these polymorphisms were found between healthy controls and breast cancer patients. The data clearly indicate that the risk of colon cancer is associated with single-nucleotide polymorphism in genes involved in base-excision repair and DNA-damage-induced responses.     

Lin28 mediates paclitaxel resistance by modulating p21, Rb and Let-7a miRNA in breast cancer cells

Resistance to chemotherapy is a major obstacle for the effective treatment of cancers. Lin28 has been shown to contribute to tumor relapse after chemotherapy; however, the relationship between Lin28 and chemoresistance remained unknown. In this study, we investigated the association of Lin28 with paclitaxel resistance and identified the underlying mechanisms of action of Lin28 in human breast cancer cell lines and tumor tissues. We found that the expression level of Lin28 was closely associated with the resistance to paclitaxel treatment. The T47D cancer cell line, which highly expresses Lin28, is more resistant to paclitaxel than the MCF7, Bcap-37 or SK-BR-3 cancer cell lines, which had low-level expression of Lin28. Knocking down of Lin28 in Lin28 high expression T47D cells increased the sensitivity to paclitaxel treatment, while stable expression of Lin28 in breast cancer cells effectively attenuated the sensitivity to paclitaxel treatment, resulting in a significant increase of IC50 values of paclitaxel. Transfection with Lin28 also significantly inhibited paclitaxel-induced apoptosis. We also found that Lin28 expression was dramatically increased in tumor tissues after neoadjuvant chemotherapy or in local relapse or metastatic breast cancer tissues. Moreover, further studies showed that p21, Rb and Let-7 miRNA were the molecular targets of Lin28. Overexpression of Lin28 in breast cancer cells considerably induced p21 and Rb expression and inhibited Let-7 miRNA levels. Our results indicate that Lin28 expression might be one mechanism underlying paclitaxel resistance in breast cancer, and Lin28 could be a potential target for overcoming paclitaxel resistance in breast cancer.     

Stromal cell-derived factor 1, a novel target of estrogen receptor action,mediates the mitogenic effects of estradiol in ovarian and breast cancer cells

Recent clinical studies estimate that 60-70% of human ovarian and breast cancers overexpress the estrogen receptor (ER). However, despite the established mitogenic effects of estrogen in these tumors, proliferative markers of hormone action are limited. In the current study, we report that the growth stimulatory cytokine stromal cell-derived factor 1 (SDF-1) is a bona fide target of estrogen action in ERalpha-positive human ovarian and breast cancer cells. Notably, estradiol treatment of BG-1 (ovarian carcinoma) and MCF-7 (breast carcinoma) cells leads to rapid and robust induction of the SDF-1alpha and beta isoforms. This response is blocked by the pure ER antagonist ICI 182,780 and is not apparent in ER-negative ovarian cells, indicating that SDF-1 regulation is ERalpha mediated. Treatment with the protein synthesis inhibitor cycloheximide had no effect on estradiol induction of induction of SDF-1 mRNA levels mRNA levels, demonstrating that SDF-1 is a direct target of ERalpha. SDF-1 protein levels, although undetectable under basal conditions, were strikingly increased by hormone both intracellularly and in the media of cultured BG-1 and MCF-7 cells. In cell proliferation assays, the mitogenic effects of estradiol were neutralized by addition of an SDF-1 antibody and mimicked by the addition of exogenous SDF-1 protein, indicating that SDF-1 mediates the proliferative actions of hormone. Furthermore, activation of the SDF-1 receptor CXCR4 stimulated BG-1 and MCF-7 cell proliferation in a manner comparable to estradiol. Taken together, these results demonstrate a novel estrogen-mediated paracrine pathway for inducing cancer cell proliferation and suggest that SDF-1 and CXCR4 may represent novel therapeutic targets in ERalpha-positive ovarian and breast tumors.     

The SH2 domain protein GRB-7 is co-amplified, overexpressed and in a tight complex with HER2 in breast cancer.

SH2 domain proteins are important components of the signal transduction pathways activated by growth factor receptor tyrosine kinases. We have been cloning SH2 domain proteins by bacterial expression cloning using the tyrosine phosphorylated C-terminus of the epidermal growth factor receptor as a probe. One of these newly cloned SH2 domain proteins, GRB-7, was mapped on mouse chromosome 11 to a region which also contains the tyrosine kinase receptor, HER2/erbB-2. The analogous chromosomal locus in man is often amplified in human breast cancer leading to overexpression of HER2. We find that GRB-7 is amplified in concert with HER2 in several breast cancer cell lines and that GRB-7 is overexpressed in both cell lines and breast tumors. GRB-7, through its SH2 domain, binds tightly to HER2 such that a large fraction of the tyrosine phosphorylated HER2 in SKBR-3 cells is bound to GRB-7. GRB-7 can also bind tyrosine phosphorylated SHC, albeit at a lower affinity than GRB2 binds SHC. We also find that GRB-7 has a strong similarity over > 300 amino acids to a newly identified gene in Caenorhabditis elegans. This region of similarity, which lies outside the SH2 domain, also contains a pleckstrin homology domain. The presence of evolutionarily conserved domains indicates that GRB-7 is likely to perform a basic signaling function. The fact that GRB-7 and HER2 are both overexpressed and bound tightly together suggests that this basic signaling pathway is greatly amplified in certain breast cancers.     

BRCA2 in American families with four or more cases of breast or ovarian cancer: recurrent and novel mutations, variable expression, penetrance, and the possibility of families whose cancer is not attributable to BRCA1 or BRCA2.

In order to evaluate the role of inherited BRCA2 mutations in American families--particularly the appearance in America of European founder mutations--the BRCA2 coding sequence, 5' UTR, and 3' UTR were screened in 22 Caucasian American kindreds with four or more cases of breast or ovarian cancer. Six mutations were found that cause a premature-termination codon; four of them have been reported elsewhere, and two are novel. In the four families with previously seen mutations, the distinct lineages at high risk of cancer were of Dutch, German, Irish, and Ashkenazi Jewish ancestry; mutations in Europe reflect these ancestries. The families with novel mutations were Puerto Rican Hispanic (exon 9 deletion 995delCAAAT) and Ashkenazi Jewish (exon 11 deletion 6425delTT). Among female BRCA2-mutation carriers, risks of breast cancer were 32% by age 50 years, 67% by age 70 years, and 80% by age 90 years, yielding a lifetime risk similar to that for BRCA1 but an older distribution of ages at onset. BRCA2 families also included multiple cases of cancers of the male breast (six cases), ovary (three cases), fallopian tube (two cases), pancreas (three cases), bladder (two cases), and prostate (two cases). Among 17 Ashkenazi Jewish families with four or more breast or ovarian cancers, 9 families (including 3 with ovarian cancer and 1 with male breast cancer) carried none of the three ancient mutations in BRCA1 or BRCA2. To date, both BRCA2 and BRCA1 have been screened by SSCA, supplemented by the protein-truncation test, in 48 families with four or more breast or ovarian cancers. Mutations have been detected in BRCA1 in 33 families, in BRCA2 in 6 families, and in neither gene in 9 families, suggesting both the probable cryptic nature of some mutations and the likelihood of at least one other BRCA gene.     

A risk-associated single nucleotide polymorphism of <Emphasis Type="Italic">SMAD7</Emphasis> is common to colorectal,gastric, and lung cancers in a Han Chinese population

SMAD7 has been demonstrated to antagonize TGF-β-mediated fibrosis, carcinogenesis, and inflammation. Two previous genome-wide association studies identified three single nucleotide polymorphisms (SNPs) (rs4939827, rs12953717 and rs4464148) in SMAD7 to be associated with colorectal cancer in a Western population. We conducted the first case–control study in a Han Chinese population to explore the associations between these three SNPs and colorectal, gastric, and lung cancers. Of the three SNPs, only rs12953717 was strongly associated with the three types of cancer, fitting the overdominant model. Compared with the CC/TT (CC combined with TT) genotype, the adjusted odds ratios for the CT genotype were 2.002 (95% CI, 1.250–3.207, P = 0.004), 1.678 (95% CI, 1.048–2.689, P = 0.031), 3.825 (95% CI, 2.310–6.335, P < 1 × 10⁻⁴), and 2.294 (95% CI, 1.537–3.343, P < 1 × 10⁻⁴), respectively, for colorectal, gastric, lung, and combined cancers. These outcomes suggest that rs12953717 is a common risk marker of these three types of cancer in the Han Chinese.