Biological mechanisms in breast cancer invasiveness: relevance to preventive interventions

Suppression of TPA-induced cancer cell invasion by Peucedanum japonicum Thunb. extract through the inhibition of PKCα/NF-κB-dependent MMP-9 expression in MCF-7 cells

Metastatic cancers spread from their site of origin (the primary site) to other parts of the body. Matrix metalloproteinase-9 (MMP-9), which degrades the extracellular matrix, is important in metastatic cancers as it plays a major role in cancer cell invasion. The present study examined the inhibitory effect of an ethanol extract of Peucedanum japonicum Thunb. (PJT) on MMP-9 expression and the invasion of MCF-7 breast cancer cells induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). Western blot analysis, gelatin zymography, and reverse transcription-quantitative PCR revealed that PJT significantly suppressed MMP-9 expression and activation in a dose-dependent manner. Furthermore, PJT attenuated TPA-induced nuclear translocation and the transcriptional activation of nuclear factor (NF)-κB. The results indicated that the PJT-mediated inhibition of TPA-induced MMP-9 expression and cell invasion involved the suppression of the PKCα/NF-κB pathway in MCF-7 cells. Thus, the inhibition of MMP-9 expression by PJT may have potential value as a therapy for restricting the invasiveness of breast cancer.

Activated Leukocyte Cell Adhesion Molecule (ALCAM) in Saudi Breast Cancer Patients as Prognostic and Predictive Indicator

BACKGROUND

Activated leukocyte cell adhesion molecules (ALCAMs) play an essential role in tumor metastasis and are higher in some patients with breast cancer.

AIM

This study aimed to evaluate ALCAM as an early diagnostic biomarker for breast cancer and how it compares with other markers.

SUBJECTS AND METHODS

One-hundred and sixty-one women were selected for this study. They were divided into three groups: Group 1 consisted of 42 healthy individuals (control) while a patients groups divided into two groups according to tumour grade, Group II, Include 58 breast cancer patient’s grade II and Group III, Include 61 patients with grade III of breast cancer. Tumour markers CEA, CA 15-3 and s ALCAM levels were determined and Group 2 consisted of breast cancer patients.

RESULTS

A highly significant elevation was recorded in s ALCAM, CA 15-3 and CEA. Percent change for grade II and grade III were [sALCAM (90, 127)], [CA15-3 (40, 72)] and [CEA (33, 156)]. Operating characteristic (ROC) curves were used to evaluate the diagnostic performance of the biomarkers ALCAM, CA15-3 and CEA with area under the curve (AUC) of (0.99 & 1.0) (AUC 0.947 & 0.99) and (AUC 0.88 & 0.94) for grade II and grade III respectively the incremental values of AUC were statistically highly significant (p < 0.001).

CONCLUSION

It could be concluded that serum ALCAM concentration represents a suitable biomarker for Saudi arabian breast carcinoma with high sensitivity and has the potential to be used as a diagnostic tool comparable to CA15-3 and CEA.

Crosstalk of the Insulin-Like Growth Factor Receptor with the Wnt Signaling Pathway in Breast Cancer

The insulin-like growth factor system has long been considered a pathway that promotes cell proliferation, survival, and transformation, and is thus a promoter of tumorigenesis. However, recent failure of clinical trials for IGF-1R inhibitors reveals the need for a better understanding of how this pathway functions in specific tumor subtypes. Ongoing studies are designed to uncover biomarkers and downstream targets to enhance therapeutic strategies. Other approaches in specific tumor models reveal complex interactions between IGF signaling and other tumor initiating pathways. Here, we review relevant background and recent studies suggesting that inhibiting the IGF-1R can amplify Wnt and Notch signaling pathways in a model of triple negative breast cancer.

Circulating levels of cell adhesion molecule L1 as a prognostic marker in gastrointestinal stromal tumor patients

BACKGROUND

L1 cell adhesion molecule (CD171) is expressed in many malignant tumors and its expression correlates with unfavourable outcome. It thus represents a target for tumor diagnosis and therapy. An earlier study conducted by our group identified L1 expression levels in primary gastrointestinal stromal tumors (GIST) as a prognostic marker. The aim of the current study was to compare L1 serum levels of GIST patients with those of healthy controls and to determine whether levels of soluble L1 in sera could serve as a prognostic marker.

METHODS

Using a sensitive enzyme-linked immunosorbent assay (ELISA), soluble L1 was measured in sera of 93 GIST patients und 151 healthy controls. Soluble L1 levels were then correlated with clinicopathological data.

RESULTS

Median levels of soluble L1 were significantly higher (p < 0.001; Mann-Whitney U test) in sera of GIST patients compared to healthy individuals. Median soluble L1 levels were particularly elevated in patients with recurrence and relapse (p < 0.05; Mann Whitney U test).

CONCLUSION

These results suggest that high soluble L1 levels predict poor prognosis and may thus be a promising tumor marker that can contribute to individualise therapy.

Repositioning chloroquine and metformin to eliminate cancer stem cell traits in pre-malignant lesions

Ideal oncology drugs would be curative after a short treatment course if they could eliminate epithelium-originated carcinomas at their non-invasive, pre-malignant stages. Such ideal molecules, which are expected to molecularly abrogate all the instrumental mechanisms acquired by migrating cancer stem cells (CSCs) to by-pass tumour suppressor barriers, might already exist. We here illustrate how system biology strategies for repositioning existing FDA-approved drugs may accelerate our therapeutic capacity to eliminate CSC traits in pre-invasive intraepithelial neoplasias. First, we describe a signalling network signature that overrides bioenergetics stress- and oncogene-induced senescence (OIS) phenomena in CSCs residing at pre-invasive lesions. Second, we functionally map the anti-malarial chloroquine and the anti-diabetic metformin ("old drugs") to their recently recognized CSC targets ("new uses") within the network. By discussing the preclinical efficacy of chloroquine and metformin to inhibiting the genesis and self-renewal of CSCs we finally underscore the expected translational impact of the "old drugs-new uses" repurposing strategy to open a new CSC-targeted chemoprevention era.

Activated leukocyte cell adhesion molecule: a novel biomarker for breast cancer

Activated leukocyte cell adhesion molecule (ALCAM) has been implicated in tumorigenesis. Our goal was to examine the levels of ALCAM, in addition to the classical breast cancer tumor markers carbohydrate antigen 15-3 (CA15-3) and carcinoembryonic antigen (CEA), in serum by quantitative enzyme-linked immunosorbent assay for diagnosis in breast cancer patients. The 3 proteins were measured in serum of 100 healthy women, 50 healthy men and 150 breast carcinoma patients. The diagnostic sensitivity and specificity of the tests were calculated and the association of serum marker concentrations with various clinicopathologic variables was examined using nonparametric Kruskal-Wallis tests. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic performance of the biomarkers. ALCAM, with area under the curve (AUC) of 0.78 [95% CI: 0.73, 0.84] outperformed CA15-3 (AUC = 0.70 [95% CI: 0.64, 0.76]) and CEA (AUC= 0.63 [95% CI: 0.56, 0.70]). The incremental values of AUC for ALCAM over that for CA15-3 were statistically significant (Delong test, p < 0.05). Combining CA15-3 and ALCAM yielded a ROC curve with an AUC of 0.81 (95% CI [0.75, 0.87]). Serum ALCAM appears to be a new biomarker for breast cancer and may have value for disease diagnosis.

Reproductive and hormonal risk factors for ductal carcinoma in situ of the breast

One-fifth of all newly diagnosed breast cancer cases are ductal carcinoma in situ (DCIS), but little is known about DCIS risk factors. Recent studies suggest that some subtypes of DCIS (high grade or comedo) share histopathologic and epidemiologic characteristics with invasive disease, whereas others (medium or low grade or non-comedo) show different patterns. To investigate whether reproductive and hormonal risk factors differ among comedo and non-comedo types of DCIS and invasive breast cancer (IBC), we used a population-based case-control study of 1,808 invasive and 446 DCIS breast cancer cases and their age and race frequency-matched controls (1,564 invasive and 458 DCIS). Three or more full-term pregnancies showed a strong inverse association with comedo-type DCIS [odds ratio (OR), 0.53; 95% confidence interval (95% CI), 0.30-0.95] and a weaker inverse association for non-comedo DCIS (OR, 0.73; 95% CI, 0.42-1.27). Several risk factors (age at first full-term pregnancy, breast-feeding, and age at menopause) showed similar associations for comedo-type DCIS and IBC but different associations for non-comedo DCIS. Ten or more years of oral contraceptive showed a positive association with comedo-type DCIS (OR, 1.31; 95% CI, 0.70-2.47) and IBC (OR, 2.33; 95% CI, 1.06-5.09) but an inverse association for non-comedo DCIS (OR, 0.51; 95% CI, 0.25-1.04). Our results support the theory that comedo-type DCIS may share hormonal and reproductive risk factors with IBC, whereas the etiology of non-comedo DCIS deserves further investigation.

Matrix metalloproteinase-2 expression correlates with cavernous sinus invasion in pituitary adenomas

The aim of this study was to evaluate the relationship between expression of matrix metalloproteinase-2 (MMP-2) and cavernous sinus invasion in pituitary adenoma.

METHOD

Tissue samples from 54 pituitary adenomas were examined for expression of MMP-2 protein by immunohistochemistry. In sixteen tumors, the expression of MMP-2 mRNA was also examined by RT-PCR. Immunostaining was semiquantatively scored based on intensity (0-3) and distribution (0-3).

RESULTS

There were 34 women and 20 men, with a mean age of 49.9 years (range 18-76). There were 12 tumors with cavernous sinus invasion, and 42 noninvasive cases. The MMP-2 score of pituitary adenomas with cavernous sinus invasion (3.9 +/- 0.5) was significantly higher than those without invasion (2.3 +/- 0.2; P < 0.01). There was no difference in MMP-2 score between macroadenomas (3.0 +/- 0.3) and microadenomas (2.1 +/- 0.4; P > 0.05), and also, no difference between the functioning adenomas (2.8 +/- 0.3) and non-functioning adenomas (2.8 +/- 0.3; P > 0.05). We found no correlation between the MMP-2 score and the Ki-67 labeling index (r2 = -0.05; P = 0.72). MMP-2 mRNA expression was also intense in invasive pituitary adenomas and was significantly higher in invasive pituitary adenomas than those without invasion (68.2 +/- 15.3; 21.8 +/- 8.2; P < 0.05).

CONCLUSION

This study suggests that MMP-2 may be associated with aggressiveness and invasion in pituitary adenoma but is not related to tumor size or secretory function. MMP-2 may be a useful tool for assessing the invasive potential.

Comorbidity as a predictor of stage of illness for patients with breast cancer

OBJECTIVE

The purpose of this research was to determine whether comorbidity affects the stage at which breast cancer is diagnosed.

METHODS

Data from the Surveillance, Epidemiology and End Results (SEER) program of the National Cancer Institute (NCI) was merged with Medicare claims for 17,468 women diagnosed with breast cancer from 1993 to 1995.

RESULTS

Women with cardiovascular disease, musculoskeletal disorders, mild-to-moderate gastrointestinal disease, and nonmalignant benign breast disease had a 13%, 7%, 14%, and 24% lower odds, respectively, of being diagnosed with advanced breast cancer. Women with diabetes, other endocrine disorders, psychiatric disorders, or hematologic disorders increased the odds of a late-stage diagnosis by 19%, 11%, 20%, and 19% respectively. Mammography screening and contact with the medical care system decreased the odds of late-stage diagnosis.

DISCUSSION

Four hypotheses are suggested to explain this link between comorbid illness and stage at diagnosis: (1) the "surveillance" hypothesis, (2) the "physiological" hypothesis, (3) the "competing demand" hypothesis, and (4) the "death from other causes" hypothesis.

CONCLUSIONS

Comorbidity may complicate the diagnostic decision-making process for breast cancer. The results suggest that contact with the medical care system improves the odds of early-stage diagnosis. Thus, barriers to access for people with chronic conditions may exacerbate those chronic conditions and increase the odds of late-stage breast cancer.

Insulin can modulate MCF-7 cell response to paclitaxel

Insulin regulates metabolism through homologous receptor tyrosine kinases, and plays a role in proliferation of breast cancer cells. Our research studied whether insulin, administered separately or in combination with paclitaxel, interferes with paclitaxel-mediated biological activity in human breast cancer cells. Not only did insulin influence paclitaxel-mediated cell microtubule reorganization, but it also influenced MCF-7 cell sensitivity to paclitaxel. Furthermore, combined administrations of insulin and paclitaxel affected MAPK pathway, Raf-1 activation and p53 expression levels. Our findings indicate that insulin seems to modulate MCF-7 cell response to paclitaxel; consequently, elevated levels of insulin could influence tumor cell resistance.

Correlates of obesity in postmenopausal women with breast cancer: comparison of genetic, demographic, disease-related, life history and dietary factors

BACKGROUND

Obesity in women has been associated with a variety of factors, including genetic predisposition, social class, early age at menarche, exercise, alcohol consumption and diet. Obesity is a risk factor for the occurrence and the recurrence of breast cancer in postmenopausal women, perhaps because of increased exposure to estrogen, insulin and insulin-like growth factors (IGFs). The progesterone receptor (PR) and the steroid hormone receptor coactivator pCIP/ACTR/AIB1/TRAM1/RAC3 (AIB1) are hypothesized to mediate signaling crosstalk between these hormonal pathways. Polymorphisms in both genes have been described and their association with breast cancer risk reported. If genetic factors contribute to obesity, and the PR and AIB1 genes influence estrogenic, insulin and IGF pathways, then genetic patterns resulting from PR and AIB1 polymorphisms may be associated with obesity in postmenopausal women.

OBJECTIVE

We compared the PR and AIB1 genotypes of postmenopausal women with breast cancer with demographic, disease-related, reproductive, lifestyle and dietary variables in terms of the strength of their relationship with obesity (BMI> or =30 kg/m2).

SUBJECTS

A total of 301 postmenopausal women previously diagnosed with Stage I, II or IIIA breast cancer, who are enrolled in the Women's Healthy Eating and Living (WHEL) study (age: 34.5-70.8 y, BMI: 17.8-54.6 kg/m2).

MEASUREMENTS

The PR polymorphism PROGINS was identified by PCR. The length of the AIB1 polyglutamine repeat was determined by PCR and nondenaturing gel electrophoresis or DNA sequencing. BMI was obtained at the baseline clinic visit upon entry into the WHEL study. Information about date of diagnosis, stage of disease, tumor hormone receptor status and adjuvant treatment received were obtained from medical records. Reproductive, menstrual history, demographic, family history of cancer, smoking history and exercise frequency and intensity information were obtained from questionnaires. Dietary and alcohol intake data came from four 24-h telephone recalls of food intake obtained at the study entry.

RESULTS

The combined inheritance of PROGINS A1/A1 and AIB1 28/29, 28/30, 28/31, 29/29 or 29/30 (AIB1 LG) genotypes (adjusted odds ratio (OR)=2.22 (95% confidence interval 1.25-3.93)) and early age at menarche (<12 y) (adjusted OR=2.34 (1.12-4.86)) were each associated with the risk for obesity. Current use of tamoxifen (adjusted OR=0.49 (0.28-0.87)) and an alcohol intake > or =10 g/day (adjusted OR=0.28 (0.11-0.77)) were inversely associated with BMI > or =30 kg/m2.

CONCLUSION

Early age at menarche and a PROGINS A1/A1+AIB1 LG genetic pattern had comparable levels of association with obesity in this cross-sectional sample of postmenopausal women with breast cancer. Since this was a cross-sectional rather than a case-control design, the association between PROGINS and AIB1 genotype and obesity found in this sample should be considered preliminary, and must be re-evaluated with a new and larger sample.

Linkage between retinoid and fatty acid receptors: implications for breast cancer prevention

Certain dietary retinoids and polyunsaturated fatty acids (PUFAs) consistently inhibit progression of mammary carcinogenesis both in animal studies and cell culture, but clinically, their effect is inconsistent. New evidence of synergistic interaction between the nuclear receptors for the two groups of nutritional agents suggests that appropriate selective ligands from each group might be combined in breast cancer chemoprevention studies. Peroxisome proliferator-activated receptor (PPAR) gamma is a nuclear receptor that is activated by PUFAs, eicosanoids and antidiabetic agents such as troglitazone. Such activation can cause growth inhibition in human mammary cancer cells in culture and the effect is enhanced by ligands of retinoic acid receptor (RAR) and retinoid X receptor (RXR). In mouse mammary tissue in organ culture, an RXR-selective ligand has been shown to enhance the effect of troglitazone in suppressing carcinogen-induced pre-neoplastic changes. A PPAR/RXR heterodimer is involved in tumour growth inhibition and has been shown to bind directly to nuclear oestrogen response elements (ERE) independently of oestrogen receptor (ER) activity. A combination of an RXR-selective retinoid with either troglitazone or else a long-chain n-3 PUFA, is proposed for a short-term study in postmenopausal women after primary surgery for intraductal breast cancer. The resulting activation of PPAR/RXR expression may increase response to retinoid administration, especially in the presence of obesity and insulin resistance, because of the ability of PPAR gamma ligands to reduce insulin-like growth factor I (IGF-I) concentrations. Serial core biopsies of breast tissue over a short term are proposed to identify changes in phenotype, which may influence progression to invasiveness. In addition to cytomorphological criteria, expression of ER alpha and beta, RAR alpha and beta, and IGF-I receptor in the nucleus should be examined.

Expression of UGT2B7, a UDP-glucuronosyltransferase implicated in the metabolism of 4-hydroxyestrone and all-trans retinoic acid, in normal human breast parenchyma and in invasive and in situ breast cancers

Glucuronidation, mediated by UDP-glucuronosyltransferases (UGTs), affects the actions and disposition of diverse endo- and xenobiotics. In the case of catecholestrogens (CEs), glucuronidation is likely to block their oxidation to quinone estrogens that are the putative mediators of CEs' actions as initiators of cancers. The goal of this study was to determine whether UGT2B7, the isoenzyme with a high affinity for 4-hydroxyestrone, is expressed in human breast parenchyma. Glucuronidation of 4-hydroxyestrone has relevance to breast carcinogenesis because quinone metabolites of 4-hydroxylated CEs can form potentially mutagenic depurinating DNA adducts, and because in breast tissue estrone is likely to be the predominant estrogen available for 4-hydroxylation. Using reverse transcriptase-polymerase chain reaction, immunocytochemistry, immunoblot analyses, and assays of glucuronidation of 4-hydroxyestrone, we show that UGT2B7 is expressed in human mammary epithelium, and that its expression is dramatically reduced in invasive breast cancers. In many in situ carcinomas, however, 4-hydroxyestrone immunostaining was not only preserved but even more intense than in normal mammary epithelium. The finding of reduced UGT2B7 protein and glucuronidation of 4-hydroxyestrone in invasive cancers suggests a tumor-suppressor function for the enzyme. Recent identification of all-trans retinoic acid as a substrate of UGT2B7 suggests that this function includes the generation of retinoyl-beta-glucuronide, a potent mediator of actions of retinoids important for maintaining epithelia in a differentiated state. Current knowledge does not provide any ready explanation for the apparent increase in UGT2B7 expression in carcinomas in situ. However, this finding, together with reduced immunostaining at loci showing breach of the basement membrane (microinvasion), suggests involvement of UGT2B7-catalyzed reaction(s) in protection against invasion of surrounding tissue by cancer cells.

Protein kinase C inhibitors as novel anticancer drugs

The role of PKC isoforms in signal transduction pathways involved in regulation of the cell cycle, apoptosis, angiogenesis, differentiation, invasiveness, senescence and drug efflux are reviewed, along with the clinical results on the current crop of PKC inhibitors, including midostaurin (PKC-412, CGP 41251, N -benzoylstaurosporine), UCN-01 (7-hydroxystaurosporine), bryostatin 1, perifosine, ilmofosine, Ro 31-8220, Ro 32-0432, GO 6976, ISIS-3521 (CGP 64128A) and the macrocyclic bis (indolyl) maleimides (LY-333531, LY-379196, LY-317615). An appreciation of the complex, often contradictory roles of PKC isoforms in signal transduction pathways involved in cancer is important for interpreting the clinical results observed with PKC inhibitors of varying selectivity. An antisense oligonucleotide, ISIS-3521 and two orally available small molecule inhibitors, LY 333531 and midostaurin, have now advanced to latter stage development for cancer and/or other indications. These compounds have varying levels of selectivity for the PKC isoforms and for the kinase and initial safety and early clinical efficacy have been encouraging. At this stage, the potential of PKC inhibition for the treatment of cancer has not been fully realised. The concurrent inhibition of multiple PKC isoforms may yet provide an improved clinical outcome in treating cancers in view of the complex interrelated roles of the PKC isoforms.

Expression of matrix metalloproteinases 2 and 9 in meningiomas associated with different degrees of brain invasiveness and edema

OBJECT

Meningiomas display clinical characteristics that vary from very benign to clearly malignant with rapid invasive growth and metastasis. Benign meningiomas differ in their invasiveness and concomitant edema. This study was undertaken to analyze the expression of matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9, respectively) in meningiomas associated with different degrees of brain invasion and edema.

METHODS

Tissue samples from 16 meningiomas were selected according to tumor invasiveness from a consecutive series of patients. Samples were analyzed for expression of both MMP-2 and MMP-9 by using in situ hybridization. The meningiomas consisted of three types: Group I, benign meningiomas that did not interfere with the arachnoid plane and exhibited no edema; Group II, benign meningiomas that invaded the arachnoid plane and caused edema; and Group III, aggressive and malignant meningiomas that caused edema and displayed brain invasion. In all 16 tumors analyzed, MMP-2 mRNA was identified. Levels of expression of MMP-2 mRNA were similar in all samples, and no correlation with increasing tumor invasiveness or associated edema could be detected. Expression of MMP-9 mRNA was identified in 14 of the 16 tumors, and a clear correlation with increasing tumor invasion into the brain was noted.

CONCLUSIONS

Meningiomas express both MMP-2 and MMP-9. Tumor invasiveness, which ranged from minor with respect to the arachnoid membrane and progressed to frank brain invasion, correlated with the extent of MMP-9 expression. The findings indicate that MMP-9 expression and brain invasion are relevant mechanisms that must be interfered with in the treatment of aggressive and malignant meningiomas. No such correlation with MMP-2 was found.