CRYβB2 enhances tumorigenesis through upregulation of nucleolin in triple negative breast cancer

Expression of β-crystallin B2 (CRYβB2) is elevated in African American (AA) breast tumors. The underlying mechanisms of CRYβB2-induced malignancy and the association of CRYβB2 protein expression with survival have not yet been described. Here, we report that the expression of CRYβB2 in breast cancer cells increases stemness, growth, and metastasis. Transcriptomics data revealed that CRYβB2 upregulates genes that are functionally associated with unfolded protein response, oxidative phosphorylation, and DNA repair, while down-regulating genes related to apoptosis. CRYβB2 in tumors promotes de-differentiation, an increase in mesenchymal markers and cancer-associated fibroblasts, and enlargement of nucleoli. Proteome microarrays identified a direct interaction between CRYβB2 and the nucleolar protein, nucleolin. CRYβB2 induces nucleolin, leading to the activation of AKT and EGFR signaling. CRISPR studies revealed a dependency on nucleolin for the pro-tumorigenic effects of CRYβB2. Triple-negative breast cancer (TNBC) xenografts with upregulated CRYβB2 are distinctively sensitive to the nucleolin aptamer, AS-1411. Lastly, in AA patients, higher levels of nucleolar CRYβB2 in primary TNBC correlates with decreased survival. In summary, CRYβB2 is upregulated in breast tumors of AA patients and induces oncogenic alterations consistent with an aggressive cancer phenotype. CRYβB2 increases sensitivity to nucleolin inhibitors and may promote breast cancer disparity.

Combinatorial Cytotoxic Effects of 2,3-Dichloro-5,8-dimethoxy-1,4-naphthoquinone and 4-hydroxytamoxifen in Triple-negative Breast Cancer Cell Lines

BACKGROUND/AIM

Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer (BC) and lacks targeted therapy and alternate therapeutic combinations. There is a necessity to increase disease-free survival in patients particularly within the first 5 years of diagnosis. 2,3-dichloro-5,8-dimethoxy-1,4-naphthoquinone (Z285), a novel 1,4 naphthoquinone analog, has been shown to have cytotoxic activity in BC cell lines and in combination with 4-hydroxytamoxifen (4-OHT). A known metabolite of tamoxifen, was postulated to decrease cell proliferation. Thus, this study investigates the use of Z285 and 4-OHT alone or in combination as a novel therapeutic alternative for TNBC.

MATERIALS AND METHODS

Cell proliferation assays were performed on MDA-MB-231, Hs578T, MCF7 and HCC1806 cell lines at varying time points with Z285 and 4-OHT alone and in combination. Furthermore, ROS activity was measured to determine the changes in oxidative stress caused by both drugs.

RESULTS

The results showed dose- and time-dependent decreases in proliferation for all cell lines when treated with Z285, 4-OHT and their combination. Combinatorial analysis performed at 72 h using Synergyfinder^® showed additive effects in MCF7, HCC1806 and Hs578T and an antagonistic response in MDA-MB-231. Z285 caused a significant increase in ROS production in three cell lines after 8 h, but HCC1806 showed no change in effect.

CONCLUSION

These promising results suggest the independent ability of each compound as a stand-alone chemotherapeutic agent, or in combinatorial therapy for the treatment of TNBC.

The Association Between the Genetic VDR SNP c.907+75C>T and Prostate Cancer Risk Is Modified by Tanning Potential

BACKGROUND

Prostate cancer (PCa) is a multifactorial disease involving complex interactions between genetic and physiological/environmental factors. Vitamin D receptor (VDR) plays a role in numerous cellular pathways and it has been suggested that VDR genetic variants influence individual susceptibility to PCa.

MATERIALS AND METHODS

Logistic regression analysis was used to assess the association of six VDR single nucleotide polymorphisms (SNPs) and factors such as tanning potential and UV sunlight exposure with PCa risk.

RESULTS

Marginal significant interactions were found, with a 2-fold increase risk of PCa between SNP 1 (c.278-69G>A) and sunlight UV exposure [odds ratio (OR)=2.02, 95% confidence intervaI (CI)=1.036-4.36; p=0.05]; and a 4-fold increase risk of PCa between SNP 4 (c.907+75C>T) and tanning potential (OR=4.40, 95% CI=0.89-29.12; p=0.0591). In contrast, SNP 5 (rs731236, TaqI) and tanning potential interaction had a protective effect by reducing the risk of PCa by 55% (β=-0.804; OR=0.448, 95% CI=0.197-9.42; p=0.0427). SNPs 2 (rs61614328) and 6 (rs533037428) did not show any association with PCa even in the presence of UV sunlight exposure.

CONCLUSION

The protective effect of SNP 4 from PCa is lost and modified by tanning potential in African Americans. This finding needs to be verified by larger studies in different ethnic populations.

Abstract A085: Common and unique breast and prostate cancer metabolic profiles in African Americans

Breast cancer (BCa) and prostate cancer (PCa) are two of the most commonly occurring invasive cancers in African American women and men, respectively. Although they arise in anatomically different organs with distinct physiological function, a unique feature of both cancers can be hormone-dependence and thus, remarkable underlying biological similarity has been observed between the two malignancies. For example, increased risk of male BCa after PCa incidence was reported previously, in a large population-based study. The purpose of this study was identification of biomarkers to improve early diagnosis in African Americans, leveraging metabolic commonalities and differences between these two cancers. Using untargeted 1H nuclear magnetic resonance (NMR) metabolomics we identified several common and unique metabolites and biological pathways in plasma samples from BCa and PCa patients compared to plasma samples from women and men with no diagnosis or family history of either type of cancer (controls). Samples were provided from the Tissue, Plasma and Clinical Bank at the Howard University Cancer Center (HUCC). Multivariate analysis demonstrated greater differentiation in the metabolic profiles between control plasma samples for both men and women, with an increase in the level of some amino acids (e.g. alanine, N-acetyl-tyrosine, asparagine, glutamine, histidine, tryptophan and tyrosine), but no differences between short chain fatty acids (2-hydroxyisovalerate, β-hydroxybutyrate). The analysis between BCa and PCa plasma profiles showed similar results. Comparison between control women versus BCa patients demonstrated decreases in all library-matched, significant metabolites except for increases in β-hydroxybutyrate and formate in patients. Analysis of control men and PCa patients showed increased levels of most amino acids but decreases in short chain fatty acids. Interestingly, pathway evaluation showed decreased glucose utilization in comparisons between both sets of control samples and cancer samples, individually, but no difference between controls versus cancer samples. Metabolically-relevant markers can serve as a viable means for earlier cancer detection, to have a major impact on cancer outcomes for African Americans, who suffer disparate burdens from these cancers, in-part because of delayed diagnoses and poor treatment efficacy associated with later-stage disease.

Citation Format: Delisha A. Stewart, Wimal W. Pathmasiri, Susan L. McRitchie, Lance Buckley, Tammey J. Naab, Robert L. DeWitty, Jr, Vikisha T. Fripp, Desta A. Beyene, Olakunle O. Kassim, Yasmine M. Kanaan, Susan J. Sumner, Robert L. Copeland, Jr. Common and unique breast and prostate cancer metabolic profiles in African Americans [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr A085.

The Association of a Novel Identified VDR SNP With Prostate Cancer in African American Men

BACKGROUND/AIM

Vitamin D receptor (VDR) is present in numerous cellular pathways and it has been suggested that VDR genetic variants influence individual susceptibility to prostate cancer. Also, analyses of single nucleotide polymorphisms (SNPs) in VDR revealed ethnicity-associated polymorphisms. The aim of this study was to identify VDR SNPs in African American men with and without prostate cancer.

MATERIALS AND METHODS

The entire VDR gene was screened for germline mutations in a case-control study by denaturing high performance liquid chromatography and DNA sequencing. Logistic regression was used to estimate the association of SNPs, age, family history, and Gleason score with prostate cancer risk.

RESULTS

Six SNPs in the non-coding regions, and one SNP in the coding region, were detected. SNP 1 (c.278-69G>A) and SNP 4 (c.907+75C>T) have not been previously reported. SNP 4 had a significant protective effect (β=-0.6, p<0.05); whereas, SNP 7 (rs7975232) showed an increase association with prostate cancer risk and high Gleason score (β=0.32, p<0.05). SNP 4, SNP 7 and age were better predictors of prostate cancer risk than family history with a high degree of sensitivity (74.7%) and specificity (92.4%).

CONCLUSION

SNP 4 and SNP 7 could be promising markers for prediction of reduced or increased prostate cancer risk, respectively.

Admixture Mapping Links RACGAP1 Regulation to Prostate Cancer in African Americans

BACKGROUND/AIM

Prostate cancer is the most common malignancy in US males. African American men have higher incidence and mortality rates than European Americans. Five single nucleotide polymorphisms are associated with PCa. We hypothesized haplotypes inferred from these SNPs are also associated with PCa.

PATIENTS AND METHODS

We genotyped SNPs in a case-control admixture mapping study. SNP haplotypes inferred for 157 PCa cases and 150 controls were used in the regression analysis.

RESULTS

We found an association between "GTCCC", "ATTCT", and "ACCCC" haplotypes and PCa after ancestry adjustment (OR=3.62, 95%CI=1.42-9.21, p=0.0070; OR=7.89, 95%CI=2.36-26.31, p=0.0008; OR=4.34, 95%CI=1.75-10.78, p=0.0016). The rs615382 variant disrupts the recombination signal binding protein with immunoglobulin kappa J binding site in Rac GTPase activating protein 1 (RACGAP1).

CONCLUSION

Disruption of notch 1 mediated-repression of RACGAP1 may contribute to PCa in African Americans.

Kernel-Based Microfluidic Constriction Assay for Tumor Sample Identification

A high-throughput multiconstriction microfluidic channels device can distinguish human breast cancer cell lines (MDA-MB-231, HCC-1806, MCF-7) from immortalized breast cells (MCF-10A) with a confidence level of ∼81-85% at a rate of 50-70 cells/min based on velocity increment differences through multiconstriction channels aligned in series. The results are likely related to the deformability differences between nonmalignant and malignant breast cells. The data were analyzed by the methods/algorithms of Ridge, nonnegative garrote on kernel machine (NGK), and Lasso using high-dimensional variables, including the cell sizes, velocities, and velocity increments. In kernel learning based methods, the prediction values of 10-fold cross-validations are used to represent the difference between two groups of data, where a value of 100% indicates the two groups are completely distinct and identifiable. The prediction value is used to represent the difference between two groups using the established algorithm classifier from high-dimensional variables. These methods were applied to heterogeneous cell populations prepared using primary tumor and adjacent normal tissue obtained from two patients. Primary breast cancer cells were distinguished from patient-matched adjacent normal cells with a prediction ratio of 70.07%-75.96% by the NGK method. Thus, this high-throughput multiconstriction microfluidic device together with the kernel learning method can be used to perturb and analyze the biomechanical status of cells obtained from small primary tumor biopsy samples. The resultant biomechanical velocity signatures identify malignancy and provide a new marker for evaluation in risk assessment.

Breast Cancer Prognosis for Young Patients

BACKGROUND/AIMS

Breast cancer (BCa) prognostication is a vital element for providing effective treatment for patients with BCa. Studies suggest that ethnicity plays a greater role in the incidence and poor prognosis of BCa in younger women than in their older counterparts. Therefore, the goal of this study was to assess the association between age and ethnicity on the overall final prognosis.

MATERIALS AND METHODS

Nottingham Prognostic Index (NPI) was used to analyze BCa prognosis using Howard University Cancer Center Tumor Registry and the National Cancer Institute's Surveillance, Epidemiology, and End Results BCa datasets. Patients were grouped according to their predicted prognosis based on NPI scheme.

RESULTS

There was no correlation between the younger patients compared to their older counterparts for any of the prognostic clusters. The significance of ethnicity in poorer prognosis for younger age is not conclusive either.

CONCLUSION

An extended prognostic tool/system needs to be evaluated for its usefulness in a clinical practice environment.

MYC amplification in subtypes of breast cancers in African American women

Background

MYC overexpression is associated with poor prognosis in breast tumors (BCa). The objective of this study was to determine the prevalence of MYC amplification and associated markers in BCa tumors from African American (AA) women and determine the associations between MYC amplification and clinico-pathological characteristics.

Methods

We analyzed 70 cases of well characterized archival breast ductal carcinoma specimens from AA women for MYC oncogene amplification. Utilizing immune histochemical analysis estrogen receptor (ER), progesterone receptor (PR), and (HER2/neu), were assessed. Cases were Luminal A (ER or PR+, Ki-67 < 14%), Luminal B (ER or PR+, Ki-67 = > 14% or ER or PR+ HER2+), HER2 (ER-, PR-, HER2+), and Triple Negative (ER-, PR-, HER2-) with basal-like phenotype. The relationship between MYC amplification and prognostic clinico-pathological characteristics was determined using chi square and logistic regression modeling.

Results

Sixty-five (97%) of the tumors showed MYC gene amplification (MYC: CEP8 > 1). Statistically significant associations were found between MYC amplification and HER2-amplified BCa, and Luminal B subtypes of BCa (p < 0.0001), stage (p < 0.001), metastasis (p < 0.001), and positive lymph node status (p = 0.039). MYC amplification was associated with HER2 status (p = 0.01) and tumor size (p = 0.01). High MYC amplification was seen in grade III carcinomas (MYC: CEP8 = 2.42), pre-menopausal women (MYC: CEP8 = 2.49), PR-negative status (MYC: CEP8 = 2.42), and ER-positive status (MYC: CEP8 = 2.4).

Conclusions

HER2 positive BCas in AA women are likely to exhibit MYC amplification. High amplification ratios suggest that MYC drives HER2 amplification, especially in HER2 positive, Luminal B, and subtypes of BCa.

DHPLC Elution Patterns of VDR PCR Products Can Predict Prostate Cancer Susceptibility in African American Men

BACKGROUND/AIM

Denaturing high-performance liquid chromatography (DHPLC) is a technique that is used to detect mutations. The aim of the present study was to determine whether DHPLC elution patterns of vitamin D receptor (VDR) gene PCR products can serve as indicators of susceptibility to prostate cancer (PCa) risk.

MATERIALS AND METHODS

DNA samples of PCa cases and controls were screened for mutations and/or polymorphisms in coding exons of VDR gene using DHPLC analysis. Logistic regression, phi-coefficient (ϕ), and Backward Wald models were used to analyze the data.

RESULTS

Similar elution patterns of exons 1, 6, 7 and 9 along with higher prevalence of heteroduplex DNA were observed in PCa samples than in controls. Exons 4 and 8 had highly significant protective effects (p<0.05). Whereas, exons 5, 7, and 9 were perfectly positively correlated with PCa risk (ϕ=1), thus presenting candidate exons significantly associated with susceptibility to PCa.

CONCLUSION

DHPLC elution patterns of the selected exons could be useful to predict susceptibility to develop PCa.

Correlates of Triple Negative Breast Cancer and Chemotherapy Patterns in Black and White Women With Breast Cancer

BACKGROUND

Triple negative breast cancer (TNBC) tumors are estrogen receptor-negative, progesterone receptor-negative, and human epidermal growth factor-negative. TNBC is responsive to chemotherapy, but chemotherapy might be underused in some patient subgroups. The goal of the present study was to characterize the patterns of chemotherapy use (uptake and completion) in TNBC patients.

PATIENTS AND METHODS

Women with primary invasive, nonmetastatic breast cancer were recruited in Washington, DC, and Detroit. Data were collected using a standardized telephone survey that captured sociocultural and health care process factors. Clinical data were abstracted from the medical records. We used χ² tests to access the association between the receipt of chemotherapy use (initiation and completion) and categorical variables, and t tests were used for continuous variables. Logistic regression models were used to evaluate the factors associated with chemotherapy uptake.

RESULTS

Women with TNBC (16% of sample) were more likely to be black than white (68% vs. 32%; P < .05). Among women with TNBC, 60% underwent chemotherapy. Chemotherapy uptake was greater for black than for white women (48.3% vs. 11.7%; P = .01) and in women without (vs. with) healthcare discrimination (35% vs. 25%; P = .04). In multivariable models, only race was associated with the receipt of chemotherapy. Black women were more likely to receive chemotherapy than were white women. The odds ratio of receiving chemotherapy by race was 4.1 (95% confidence interval, 1.3-13.1). Each 1-year increase in age was associated with a lower likelihood of chemotherapy completion (odds ratio, 0.9; 95% confidence interval, 0.826-0.981; P = .02). Women with at least some college were less likely to complete chemotherapy than were those with other education levels (P = .02).

CONCLUSION

A substantial number of TNBC patients failed to receive and/or complete chemotherapy. Differences in chemotherapy uptake by race and sociocultural factors diminished in multivariable models but age and stage remained significant. Suboptimal treatment among women with TNBC could contribute to adverse outcomes. Future investigations are necessary to assess whether the noninitiation and/or noncompletion of chemotherapy is clinically warranted.

Risk of prostate cancer in African-American men: Evidence of mixed effects of dietary quercetin by serum vitamin D status

BACKGROUND

African-American (AA) men experience higher rates of prostate cancer (PCa) and vitamin D (vitD) deficiency than white men. VitD is promoted for PCa prevention, but there is conflicting data on the association between vitD and PCa. We examined the association between serum vitD and dietary quercetin and their interaction with PCa risk in AA men.

METHODS

Participants included 90 AA men with PCa undergoing treatment at Howard University Hospital (HUH) and 62 controls participating in HUH's free PCa screening program. We measured serum 25-hydroxy vitD [25(OH)D] and used the 98.2 item Block Brief 2000 Food Frequency Questionnaires to measure dietary intake of quercetin and other nutrients. Case and control groups were compared using a two-sample t-test for continuous risk factors and a Fisher exact test for categorical factors. Associations between risk factors and PCa risk were examined via age-adjusted logistic regression models.

RESULTS

Interaction effects of dietary quercetin and serum vitD on PCa status were observed. AA men (age 40-70) with normal levels of serum vitD (>30 ng/ml) had a 71% lower risk of PCa compared to AA men with vitD deficiency (OR = 0.29, 95%CI: 0.08-1.03; P = 0.055). In individuals with vitD deficiency, increased dietary quercetin showed a tendency toward lower risk of PCa (OR = 0.91, 95%CI: 0.82-1.00; P = 0.054, age-adjusted) while men with normal vitD were at elevated risk (OR = 1.23, 95%CI: 1.04-1.45).

CONCLUSION

These findings suggest that AA men who are at a higher risk of PCa may benefit more from vitD intake, and supplementation with dietary quercetin may increase the risk of PCa in AA men with normal vitD levels. Further studies with larger populations are needed to better understand the impact of the interaction between sera vitD levels and supplementation with quercetin on PCa in AA men.

Apoptotic Effects of Novel Dithiocarbamate Analogs of Emetine in Prostate Cancer Cell Lines

BACKGROUND/AIM

Prostate cancer is one of the leading causes of death in American males. Emetine, a naturally-derived alkaloid from the Ipecacuanha plant, has been shown to have potential for anti-tumorigenic effects for cancer treatments. The objective of this study was to characterize novel emetine dithiocarbamate (EMTDTC) analogs for potent anti-tumorigenic activity with minimal toxicity to normal prostate cells and identify targeted apoptotic regulatory genes. The leading key compounds, EMTDTC-55 and EMTDTC-56 were studied.

MATERIALS AND METHODS

Established methods of cell flow cytometry were used to analyze apoptotic potential in prostate cancer cell lines (DU145, PC3 and LNCaP) and real time-polymerase chain reaction (PCR) for identifying key genes mediating apoptosis.

RESULTS

The effect of EMTDTC-55 on DU145, LNCaP and PC3 revealed significant anti-tumorigenic activities. Both compounds showed highly significant apoptotic potential on days 3 and 5 in the prostate cancer cells. Key apoptotic genes were differentially regulated suggestive of cell-cycle arrest and apoptotic induction in androgen-independent cell lines, DU145 and PC3, by both compounds. However, in the androgen-dependent cell line LNCaP, cells were marginally affected by EMTDTC-55, but significant apoptosis was observed by EMTDTC-56 leading to cell-cycle arrest.

CONCLUSION

Both dithiocarbamate compounds EMTDTC-55 and EMTDTC-56 have significant chemotherapeutic potential in moderately metastatic DU145 and highly metastatic PC3 cells.

SPINK1 Promoter Variants Are Associated with Prostate Cancer Predisposing Alterations in Benign Prostatic Hyperplasia Patients

BACKGROUND/AIM

Several studies reported that patients with benign prostatic hyperplasia (BPH) experienced a 10% increased incidence of prostate cancer (PCa) after the first 5 years of diagnosis. We investigated the association between single nucleotide polymorphisms (SNPs) in the promoter of Serine Protease Inhibitor Kazal Type 1 (SPINK1) and the increased risk of BPH and PCa.

MATERIALS AND METHODS

We genotyped three SNPs in a cases-control study, including BPH and PCa cases. Multiple logistic regression models were applied to analyze clinical and genotypic data.

RESULTS

We found an inverse association between SNP rs10035432 and BPH under the log-additive (p=0.007) model. No association was found between these SNPs and PCa risk. However, we observed a possible association between rs1432982 and lower-grade PCa (p=0.05) under the recessive model.

CONCLUSION

SPINK1 promoter variants are likely to be associated with the risk of BPH.

Vitamin D receptor genetic polymorphisms are associated with PSA level, Gleason score and prostate cancer risk in African-American men

BACKGROUND/AIM

Several studies have revealed an association between single nucleotide polymorphisms (SNPs) in the VDR gene and prostate cancer (PCa) risk in European and Asian populations. To investigate whether VDR SNPs are associated with PCa risk in African-American (AA) men, nine VDR SNPs were analyzed in a case-control study.

MATERIALS AND METHODS

Multiple and binary logistic regression models were applied to analyze the clinical and genotypic data.

RESULTS

rs731236 and rs7975232 were significantly associated with PCa risk (p<0.05). In the analysis of clinical phenotypes, rs731236, rs1544410 and rs3782905 were strongly associated with high PSA level (p<0.05), whereas rs1544410 and rs2239185 showed a statistically significant association with high Gleason score (p<0.05). Haplotype analysis revealed several VDR haplotypes associated with PCa risk. Additionally, a trend existed, where as the number of risk alleles increased in the haplotype, the greater was the association with risk (p-trend=0.01).

CONCLUSION

These results suggest that the VDR SNPs may be associated with PCa risk and other clinical phenotypes of PCa in AA men.

Antiproliferative activities of Fagara xanthoxyloides and Pseudocedrela kotschyi against prostate cancer cell lines

BACKGROUND/AIM

Roots of Fagara zanthoxyloides and Pseudocedrela kotchyii are used as chewing sticks and as medicinal remedies for diarrhea, cough and fever in West Africa. Extracts of the two plants also possess anti-bacterial, anti-fungal and anti-malarial activities. The aim of the present study was to determine the effects of such extracts on the growth, proliferation and induction of apoptosis in four prostate cancer cell lines. Materials and Methods. Androgen-independent PC3 and DU-145 and androgen-dependent LNCaP and CWR-22 prostate cancer cell lines were cultured for five days with different concentrations of the extracts and examined for growth inhibition and evidence of apoptosis.

RESULTS

Irrespective of their androgen dependence, all four cancer cell lines exhibited a dose-dependent decrease in cell proliferation and viability by the 3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazolium bromide (MTT) assay and in induction of apoptosis. The results also show that LNCap cells were the most sensitive to the two extracts, with highest inhibition at day 3 and exhibiting the highest rate of apoptosis. Conclusion. These observations suggest that F. zanthoxyloides and P. kotchyii could serve as potential chemopreventive agents in the treatment of prostate cancer.

Metabolic profile of triple-negative breast cancer in African-American women reveals potential biomarkers of aggressive disease

Expression of estrogen receptor (ER), progesterone receptor (PR), and the human epidermal growth factor receptor 2 (HER2) can subdivide breast carcinomas into clinically meaningful classes. Cancers lacking expression of all three of these receptors (triple-negative breast cancer; TNBC) is of particular interest for molecular research because these tumors currently have no effective targets for therapy. Furthermore, TNBCs are relatively more prevalent among African-American women and can account for some of the health disparities associated with breast cancer. We approached a molecular understanding of how TNBC differs from ER(+) breast cancer through a comprehensive gas chromatography (GC)-mass spectrometry (MS) and liquid chromatography (LC)/MS/MS-based and unbiased metabolomic analysis of a series of breast carcinomas from African-American patients. Remarkably, global metabolomic profiling of tumor tissues identified a total of 418 distinct metabolites, out of which 133 (31.8%) were shown to differ between the ER(+) and TNBC tumors with statistical probability of p<0.05. Specific biochemical pathways affected included those reflecting general increases in energy metabolism and transmethylation in the TNBC tumors when compared to ER(+) tumors. Additionally, biochemicals associated with increased proliferation, redox balance and the recently proposed oncometabolites, sarcosine and 2-hydroxyglutarate, were also detected at higher levels in the TNBC versus ER(+) tumors. These studies demonstrate that TNBC tumors have metabolic signatures that distinguish them from ER(+) tumors and suggest that distinctive metabolic characteristics of these tumors might offer new targets for treatment.

Use of tanning potential as a predictor for prostate cancer risk in African-American men

BACKGROUND/AIM

Vitamin D deficiency in African-Americans is common due to the high melanin content of the skin that reduces the absorption of UV radiation. To determine if there is a correlation between UV exposure, tanning potential and vitamin D with prostate cancer (PC) risk, we conducted a case-control study of 183 African-American men aged 40 years and older residing in the Washington, DC area.

PATIENTS AND METHODS

PC status was described as a binary variable as the presence or absence of cancer and the environmental factors as continuous variables. We used a logistic regression model describing PC as the response, while age, tanning potential, sunlight and vitamin D were treated as the predictors.

RESULTS

Men aged 60 years and older had a seven-fold increased risk for developing PC compared to those aged 50 years and less (p<0.003). Tanning potential was a significant (p=0.05) risk factor for PC, while sunlight exposure and vitamin D were not. Tanning potential was also significant (p=0.044) when adjusted for vitamin D and age. However, tanning potential was only marginally significant when adjusted for sunlight exposure (p=0.064) CONCLUSION: The findings of this study indicate that tanning potential may be a predictor for PC risk in African-American men.

Strong association of fascin expression with triple negative breast cancer and basal-like phenotype in African-American women

BACKGROUND

Fascin, an actin bundling protein, plays a critical role in cell motility due to formation of actin rich protrusions called filopodia, important in cell migration, invasion and metastatic spread. Fascin overexpression has been associated with epithelial to mesenchymal transition and correlates with progression and unfavourable prognosis in breast carcinoma.

OBJECTIVE

To evaluate fascin expression by immunohistochemistry and correlate the expression pattern with clinicopathological parameters in breast cancer in African-American (AA) women, in whom triple negative breast cancer (TNBC), an aggressive subtype, is more prevalent.

METHODS

Tissue microarrays were constructed from formalin-fixed, paraffin-embedded blocks of tumour tissue from primary breast carcinomas in 202 AA women. Immunohistochemical detection of fascin was correlated with four major subtypes of breast carcinoma (luminal A, luminal B, human epidermal growth factor receptor 2 and triple negative (TN)) and other clinicopathological factors, including age, grade, tumour size, stage, regional lymph node status and survival.

RESULTS

We observed a significant association between fascin expression and TN subtype, oestrogen receptor (ER) negativity, progesterone receptor (PR) negativity, Elston-Nottingham (EN) grade 3 and decreased overall survival. There was also a significant association between expression of CK 5/6, a marker of basal-like phenotype, and fascin expression.

CONCLUSION

These results suggest that fascin is a marker for TN subtype having a basal-like phenotype and decreased overall survival. Fascin may represent a target for therapy in TNBC in AA women.

Cytotoxic effects of N-(3-chloro-1,4-dioxo 1,4-dihydro-naphthalen-2-yl)-benzamide on androgen-dependent and -independent prostate cancer cell lines

BACKGROUND

Worldwide among men, prostate cancer ranks third in cancer occurrence and sixth in cancer mortality. A number of 1, 4-naphthoquinone derivatives have been identified that possess significant pharmacological effects associated with antitumor activities. In this study, the in vitro effects of N-(3-chloro-1,4-dioxo 1,4-dihydro-naphthalen-2-yl)-benzamide (NCDDNB) were evaluated on androgen-dependent (CWR-22) and androgen-independent (PC-3, DU-145) human prostate cancer cell lines, and on a normal bone marrow cell line (HS-5). Specifically, the in vitro activity of this compound on cell cycle regulation and apoptosis was evaluated.

MATERIALS AND METHODS

Established methods of cell viability, cell cycle, Western blot and apoptosis were used.

RESULTS

The effect of NCDDNB on CWR-22, PC-3, DU-145 and HS-5 cells revealed significant anti-tumor activities with IC(50)s, of 2.5, 2.5, 6.5, and 25 muM respectively. The results of cell cycle analysis showed that NCDDNB arrested PC-3, DU-145, and CWR-22 cells in the G(1)-phase of the cell cycle. The compound showed no effect on the cell cycle progression in the HS-5 bone marrow cell line. These findings were further validated using Western blot analysis. NCDDNB showed the greatest amount of apoptosis in the androgen-independent PC-3 cells in a time-dependent manner with the apoptotic apex at day 5 of treatment. Furthermore, NCDDNB induced-apoptosis in DU-145 and CWR-22 cells peaked at day 3 of treatment.

CONCLUSION

Although the mechanism of action of this compound has not been completely elucidated, the effect on the cell cycle and the induction of apoptosis in different prostate cancer cell lines prompted us to carry out a more in-depth preclinical evaluation. This study suggests that NCDDNB may have an impact on treatment of prostate cancer while protecting the bone marrow.

Biological evaluation of 2,3-dichloro-5,8-dimethoxy-1,4-naphthoquinone as an anti-breast cancer agent

BACKGROUND

Breast cancer is the most frequent cancer and the second leading cause of cancer deaths in women today. A number of 1,4-naphthoquinone derivatives have been found to possess significant pharmacological effects associated with marked antimicrobial and antitumor activities. In the present study, the in vitro effect of 2,3-dichloro-5,8-dimethoxy-1,4-naphthoquinone (DCDMNQ) was evaluated on estrogen-positive MCF-7 and estrogen-negative MDA-MB-436 and Hs-578T human breast cancer cell lines. Moreover, the in vitro activity of this compound on cell cycle regulation and apoptosis were evaluated.

MATERIALS AND METHODS

Established methods of cell viability, cell cycle, Western blot and apoptosis were used.

RESULTS

The effect of DCDMNQ on MCF-7, MDA-MB-436 and Hs-578T cells revealed significant antitumor activities with IC(50)s, of 0.6 +/- 0.02, 1.4 +/- 0.25 and 3.1 +/- 0.4 microM respectively. Cell cycle analysis showed that DCDMNQ inhibited progression through the cell cycle in MCF-7 and MDA-MB-436 cell lines in a time-dependent manner. DCDMNQ arrested cells in the S-phase of the cell cycle with the greatest proportion of cells in the S-phase by day 5. This cell-cycle arrest was corroborated by inhibition of topoisomerase I induced by DCDMNQ. These findings were further validated using Western blot analysis of retinoblastoma protein time-dependent phosphorylation. Furthermore, DCDMNQ induced apoptosis in both estrogen-positive and -negative cell lines in a time-dependent manner. However, the highest percentages of apoptotic cells were observed in the MDA-MB-436 cell line.

CONCLUSION

Although the mechanism of action of DCDMNQ has not been completely elucidated, it appears that this compound can inhibit topoisomerase I in a concentration-dependent manner. These promising results to explore novel naphthoquinone analogues as potential breast cancer agents. This study suggests that DCDMNQ may have an impact on treatment of estrogen-positive and -negative breast cancer while protecting the bone marrow.

Antiapoptotic effects of nicotine in its protection against salsolinol-induced cytotoxicity

Salsolinol (1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline), a metabolite of dopamine, may act as an endogenous neurotoxin and contribute to the etiology of Parkinson's disease (PD). The inverse relationship between smoking and PD prompted our previous investigation and the report of protective effects of nicotine against salsolinol-induced toxicity in cultured SH-SY5Y cells (Copeland et al., Neurotox. Res. 8:289, 2005). These cells, derived from human neuroblastoma cells, express dopaminergic activity and are used as a model of nigral dopaminergic cells, the major site of pathology in PD. The purpose of the current study was to investigate whether apoptotic or antiapoptotic mechanisms were responsible for the observed effects of salsolinol and nicotine, respectively. Moreover, it was of interest to determine whether the actions of nicotine are mediated through nicotinic receptors. SH-SY5Y cells were exposed to 0.4 or 0.7 mM salsolinol with and without pretreatment in combination of 0.1 mM nicotine and 0.1 mM mecamylamine and were exposed for 24 and 48 h. Various parameters including cell cycle perturbations (reflected in propidium iodide DNA staining); cell cycle regulator retinoblastoma protein (reflected in the Western blot), apoptosis (reflected in annexin V/propidium iodide staining followed by flow cytometry) were analyzed. Salsolinol caused an arrest of the cells in G1-phase of cell cycle and an increase in apoptotic indices, whereas pretreatment with nicotine attenuated or completely blocked the effects of salsolinol. Nicotine effects in turn, were totally blocked by mecamylamine (0.1 mM). The results suggest that apoptosis is a major mechanism for salsolinol-induced toxicity and that antiapoptotic effects of nicotine, mediated by nicotinic receptors, may play a primary role in its neuroprotective effects. Hence, nicotinic agonists in combination with other antiapoptotic agents may be of substantial benefit in at least a subpopulation of Parkinson patients.

Cytotoxicity of 2,3-dichloro-5,8-dimethoxy-1,4-naphthoquinone in androgen-dependent and -independent prostate cancer cell lines

BACKGROUND

Prostate cancer ranks third worldwide in cancer incidence and sixth in cancer mortality among men. A number of 1,4-naphthoquinone derivatives have been found to possess significant pharmacological effects associated with marked antimicrobial and antitumor activities. In the present study the in vitro effect of 2,3-dichloro-5,8-dimethoxy-1,4-naphthoquinone (DCDMNQ) was evaluated on androgen-dependent (LNCaP, CWR-22) and androgen-independent (PC-3. DU-145) human prostate cancer cell lines, and/or a normal bone marrow cell line (HS-5). Moreover, the in vitro activity of this compound on cell cycle regulation and apoptosis was evaluated.

MATERIALS AND METHODS

Established methods of cell viability, cell cycle, Western blot and apoptosis were used.

RESULTS

The effect of DCDMNQ on LNCaP, CWR-22, PC-3, DU-145 and HS-5 cells revealed significant anti-tumor activities with IC50s, of 1, 3. 1.5, 3 and 10 microM respectively. Cell cycle analysis showed that DCDMNQ inhibited progression through the cell cycle in PC-3 and DU-145 cell lines in a time-dependent manner. The result for the CWR-22 cell line showed that DCDMNQ arrested cells in the G -phase of the cell cycle with the greatest proportion of cells in the G1-phase by day 5; however, the LNCaP cell line was inconsistent. The compound showed no effect on the cell cycle progression in the bone marrow HS-5 cell line. These findings were further validated using Western blot analysis. Furthermore, DCDMNQ induced apoptosis in the androgen-independent cells, preferentially over that of the androgen-dependent cell lines, in a time-dependent manner.

CONCLUSION

Although the mechanism of action of this compound has not been completely elucidated, the effect on the cell cycle and the induction of apoptosis in different prostate cancer cell lines prompted us to carry out a more in-depth preclinical evaluation of it. This study suggests that DCDMNQ may have an impact on treatment of prostate cancer while protecting the bone marrow.

Neuroprotective effects of nicotine against salsolinol-induced cytotoxicity: implications for Parkinson's disease

Parkinson's disease is associated with degeneration of dopaminergic cell bodies in the substantia nigra. It has been suggested that salsolinol, an endogenous metabolite of dopamine, may be involved in this process. An inverse relationship between Parkinson's disease and smoking (nicotine intake) has been observed in epidemiological studies. Moreover, neuroprotective effects of nicotine in various experimental models have been observed. In this study we sought to determine whether salsolinol-induced cytotoxicity in SH-SY5Y human neuroblastoma cells, a cloned cell line which expresses dopaminergic activity, could also be prevented by nicotine pretreatment, and if so, which nicotinic receptors may mediate the actions of nicotine. Exposure of SH-SY5Y cells to 0.8 mM salsolinol for 24 hours resulted in approximately 80% cell death as determined by 3,[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Pretreatment of cells with 0.1 mM nicotine resulted in inhibition of salsolinol-induced cytotoxicity. The effects of nicotine were blocked by mecamylamine, a non-selective nicotinic antagonist as well as conotoxins with selective antagonism against alpha3-containing nicotinic receptor subunits. The effects of nicotine were not affected by dihydro-beta-erythroidine or methyllycaconitine, selective antagonists against alpha4-beta2 or alpha7 nicotinic receptors, respectively. It is suggested that selective nicotinic agonists may be of therapeutic potential in at least a subpopulation of Parkinsonian patients.