Saraswati Sukumar - Academia.edu (original) (raw)

Papers by Saraswati Sukumar

Clinical Cancer Research, Jun 1, 2006

The challenges of cytology for accurate diagnosis of breast cancer are well recognized. We previo... more The challenges of cytology for accurate diagnosis of breast cancer are well recognized. We previously showed that normal and tumor tissue can be distinguished using a technique called quantitative multiplex methylation-specific PCR (QM-MSP). We hypothesized that quantitative analysis of methylated genes will provide enhanced detection of cancer cells present in cytologic specimens. Experimental Design: QM-MSP was done on ductal lavage cells from a set of 37 ductal lavage samples from women undergoing mastectomy (27 with cancer and 3 without). Duct histology information was available for each lavaged duct. QM-MSP data was assessed by measuring cumulative methylation index and by receiver operating characteristic threshold analysis.To determine the baseline level of methylation for each gene in this population, cells from 60 ducts of women at high risk of developing breast cancer were analyzed. Results: QM-MSP findings on a panel of nine genes were correlated to duct histology and ductal lavage cytology. Cytology detected cancer in 33% (7 of 21 ducts) with a specificity of 99% (92 of 93). QM-MSP detected cancer as calculated by cumulative methylation index with a sensitivity of 62% (13 of 21) and specificity of 82% (62 of 76) and by receiver operating characteristic threshold analysis with a sensitivity of 71% (15 of 21) and specificity of 83% (63 of 76). Conclusions: Compared with cytology, QM-MSP doubled the sensitivity of detection of cancer. This study provides proof of principle by showing the advantages of using methylation analyses to query cytologic specimens and indicates its potential use in diagnosis and in stratifying risk.

Table S1. Correlations between parameters that influence the quality of the rFNA sample (119 wome... more Table S1. Correlations between parameters that influence the quality of the rFNA sample (119 women) Table S2. Correlation between Breast and serum hormone concentrations. Table S3. Cytology according to menopausal status and menstrual cycle.

Clinical Cancer Research, Dec 1, 2005

To establish a comprehensive proteomic approach for biomarker discovery and validation in breast ... more To establish a comprehensive proteomic approach for biomarker discovery and validation in breast fluid. Experimental Design: A total of 95 specimens from three institutions were used including 10 nipple aspiration fluid (5 stage I/II cancerous breasts and 5 age-matched healthy controls), 42 ductal lavage fluid from 14 patients with unilateral stage I/II cancer (25 from 9 cancerous breasts and 17 from 7 contralateral breasts), and 42 ductal lavage fluid from 14 high-risk women (multiple ducts repeated lavage). Differentially expressed protein/peptides were discovered by proteomic analysis of training sample, using ProteinChip arrays and surface-enhanced laser desorption ionization (SELDI) time-of-flight mass spectrometry, and validated on independently collected testing samples. After protein identification, ELISA was done to confirm the SELDI findings. Results: We were able to obtain reproducible protein profiles using minimal amount of protein (1 Ag) by applying an optimized chip protocol and SELDI.We were able to select cancer-associated biomarkers despite large individual variability by applying both unsupervised and supervised cluster analysis. Furthermore, we were able to train and test candidate biomarkers on independently collected samples and identified one component of a multimarker panel as human neutrophil peptides 1to 3. Conclusions: Breast fluid is a rich source of breast cancer biomarkers. In combination with highthroughput novel proteomic profiling technology and multicenter study design, markers that are highly specific to breast cancer can be discovered and validated. Our observations also suggest that persistent elevation of human neutrophil peptide in high-risk women may imply early onset of cancer not yet detectable by current detection method. Proof of this hypothesis requires follow-up on a larger study population. Breast cancer is the most commonly diagnosed cancer among women. Presymptomatic screening to detect early-stage breast cancer while it is still resectable could potentially reduce breast cancer-related mortality. Unfortunately, only 63% (1992-1999, United States) of the breast cancers are localized at the time of diagnosis (1). Small lesions are frequently missed and may not be visible even by mammography, particularly in young women and women with dense breast tissue (2). Molecular Imaging, Diagnosis, Prognosis

Journal of Clinical Oncology, May 20, 2021

10520 Background: Alterations in DNA methylation occur early in tumorigenesis, and are a potentia... more 10520 Background: Alterations in DNA methylation occur early in tumorigenesis, and are a potential breast cancer risk biomarker. We previously reported a study where healthy volunteers underwent random fine needle aspiration (rFNA) of the breasts; cumulative methylation index of eight preselected tumor suppressor genes (CMI) was associated with the presence of cytological atypia in rFNA samples. We now report 10-year follow-up of this population, to evaluate whether increased CMI is associated with subsequent breast cancer development. Methods: 380 women, unselected by breast cancer risk, were enrolled. Demographics, breast cancer risk factors, lifetime Gail model risk estimates (Gail-LR), and %breast density were obtained at baseline. rFNA samples were assessed for cytopathology (Masood Score, MS) and CMI. Patients were contacted annually for 10 years to ascertain development of invasive or non-invasive breast cancer. In univariate analysis, log-rank test was used to compare breast cancer incidence rates between individuals with high and low baseline measures (separated by median). Area under the ROC curve was used to evaluate the cancer prediction accuracy. In multivariate analysis, the effect of CMI (after log-transformation to reduce skewness) was further studied using Cox regression model adjusting for confounding baseline variables. Results: 362 women participated in follow up. At a median follow up time of 9.5 years after rFNA sampling, 16 women developed invasive or non-invasive breast cancer. There were no significant differences between women who developed cancer and those that did not in regard to demographic factors, %breast density, MS, or Gail-LR. On univariate analysis, Gail-LR was higher in women who developed cancer (13.0 vs. 16.5, p=0.08). The largest hazard ratios were observed from high breast density (2.30, 95% CI 0.8, 6.6) and high CMI (2.26, 95% CI 0.8, 6.6, p=0.07). In breast cancer prediction, the AUC for CMI was 0.64 (95% CI 0.51, 0.77). In separate bivariable models that adjusted for age, Gail-LR, MS, and %breast density, the HR for log CMI was consistently above unity, with a p value consistently below 0.1, except for the model that included MS (see Table). Conclusions: Elevated CMI has potential as a robust predictor of future breast cancer occurrence in average risk women, even when adjusted for breast density or cytologic atypia. Our prior analysis established that CMI is not susceptible to variation with menstrual cycle phase and menopausal status. These features support its further evaluation in larger trials. Clinical trial information: NCT00896636 .[Table: see text]

Cancers

Breast ductal carcinoma in situ (DCIS) is clinically challenging, featuring high diagnosis rates ... more Breast ductal carcinoma in situ (DCIS) is clinically challenging, featuring high diagnosis rates and few targeted therapies. Expression/signaling from junctional adhesion molecule-A (JAM-A) has been linked to poor prognosis in invasive breast cancers, but its role in DCIS is unknown. Since progression from DCIS to invasive cancer has been linked with overexpression of the human epidermal growth factor receptor-2 (HER2), and JAM-A regulates HER2 expression, we evaluated JAM-A as a therapeutic target in DCIS. JAM-A expression was immunohistochemically assessed in patient DCIS tissues. A novel JAM-A antagonist (JBS2) was designed and tested alone/in combination with the HER2 kinase inhibitor lapatinib, using SUM-225 cells in vitro and in vivo as validated DCIS models. Murine tumors were proteomically analyzed. JAM-A expression was moderate/high in 96% of DCIS patient tissues, versus 23% of normal adjacent tissues. JBS2 bound to recombinant JAM-A, inhibiting cell viability in SUM-225 ce...

npj Breast Cancer, 2021

Preoperative staging of suspicious axillary lymph nodes (ALNs) allows patients to be triaged to A... more Preoperative staging of suspicious axillary lymph nodes (ALNs) allows patients to be triaged to ALN dissection or to sentinel lymph node biopsy (SLNB). Ultrasound-guided fine needle aspiration (FNA) and cytology of ALN is moderately sensitive but its clinical utility relies heavily on the cytologist’s experience. We proposed that the 5-h automated GeneXpert system-based prototype breast cancer detection assay (BCDA) that quantitatively measures DNA methylation in ten tumor-specific gene markers could provide a facile, accurate test for detecting cancer in FNA of enlarged lymph nodes. We validated the assay in ALN-FNA samples from a prospective study of patients (N = 230) undergoing SLNB. In a blinded analysis of 218 evaluable LN-FNAs from 108 malignant and 110 benign LNs by histology, BCDA displayed a sensitivity of 90.7% and specificity of 99.1%, achieving an area under the ROC curve, AUC of 0.958 (95% CI: 0.928–0.989; P < 0.0001). Next, we conducted a study of archival FNAs of ...

Frontiers in Oncology, 2021

Blocking tumor angiogenesis is an appealing therapeutic strategy, but to date, success has been e... more Blocking tumor angiogenesis is an appealing therapeutic strategy, but to date, success has been elusive. We previously identified HEYL, a downstream target of Notch signaling, as an overexpressed gene in both breast cancer cells and as a tumor endothelial marker, suggesting that HEYL overexpression in both compartments may contribute to neoangiogenesis. Carcinomas arising in double transgenic Her2-neu/HeyL mice showed higher tumor vessel density and significantly faster growth than tumors in parental Her2/neu mice. Providing mechanistic insight, microarray-based mRNA profiling of HS578T-tet-off-HEYL human breast cancer cells revealed upregulation of several angiogenic factors including CXCL1/2/3 upon HEYL expression, which was validated by RT-qPCR and protein array analysis. Upregulation of the cytokines CXCL1/2/3 occurred through direct binding of HEYL to their promoter sequences. We found that vessel growth and migration of human vascular endothelial cells (HUVECs) was promoted by...

Cancers, 2020

The function of BRCA1/2 proteins is essential for maintaining genomic integrity in all cell types... more The function of BRCA1/2 proteins is essential for maintaining genomic integrity in all cell types. However, why women who carry deleterious germline mutations in BRCA face an extremely high risk of developing breast and ovarian cancers specifically has remained an enigma. We propose that breast-specific epigenetic modifications, which regulate tissue differentiation, could team up with BRCA deficiency and affect tissue susceptibility to cancer. In earlier work, we compared genome-wide methylation profiles of various normal epithelial tissues and identified breast-specific methylated gene promoter regions. Here, we focused on deltaNp73, the truncated isoform of p73, which possesses antiapoptotic and pro-oncogenic functions. We showed that the promoter of deltaNp73 is unmethylated in normal human breast epithelium and methylated in various other normal epithelial tissues and cell types. Accordingly, deltaNp73 was markedly induced by DNA damage in human mammary epithelial cells (HMECs)...

Science Advances, 2020

Systemic exposure to nanoparticles induces immune responses that lead to anticancer immune activa... more Systemic exposure to nanoparticles induces immune responses that lead to anticancer immune activation.

Nature Communications, 2019

Myoepithelial cells play key roles in normal mammary gland development and in limiting pre-invasi... more Myoepithelial cells play key roles in normal mammary gland development and in limiting pre-invasive to invasive breast tumor progression, yet their differentiation and perturbation in ductal carcinoma in situ (DCIS) are poorly understood. Here, we investigated myoepithelial cells in normal breast tissues of BRCA1 and BRCA2 germline mutation carriers and in non-carrier controls, and in sporadic DCIS. We found that in the normal breast of non-carriers, myoepithelial cells frequently co-express the p63 and TCF7 transcription factors and that p63 and TCF7 show overlapping chromatin peaks associated with differentiated myoepithelium-specific genes. In contrast, in normal breast tissues of BRCA1 mutation carriers the frequency of p63+TCF7+ myoepithelial cells is significantly decreased and p63 and TCF7 chromatin peaks do not overlap. These myoepithelial perturbations in normal breast tissues of BRCA1 germline mutation carriers may play a role in their higher risk of breast cancer. The fra...

Clinical Cancer Research, 2019

Purpose:An unmet need in low-resource countries is an automated breast cancer detection assay to ... more Purpose:An unmet need in low-resource countries is an automated breast cancer detection assay to prioritize women who should undergo core breast biopsy and pathologic review. Therefore, we sought to identify and validate a panel of methylated DNA markers to discriminate between cancer and benign breast lesions using cells obtained by fine-needle aspiration (FNA).Experimental Design: Two case–control studies were conducted comparing cancer and benign breast tissue identified from clinical repositories in the United States, China, and South Africa for marker selection/training (N = 226) and testing (N = 246). Twenty-five methylated markers were assayed by Quantitative Multiplex-Methylation-Specific PCR (QM-MSP) to select and test a cancer-specific panel. Next, a pilot study was conducted on archival FNAs (49 benign, 24 invasive) from women with mammographically suspicious lesions using a newly developed, 5-hour, quantitative, automated cartridge system. We calculated sensitivity, spec...

Breast Cancer Research, 2018

Background: A combination of entinostat, all-trans retinoic acid, and doxorubicin (EAD) induces c... more Background: A combination of entinostat, all-trans retinoic acid, and doxorubicin (EAD) induces cell death and differentiation and causes significant regression of xenografts of triple-negative breast cancer (TNBC). Methods: We investigated the mechanisms underlying the antitumor effects of each component of the EAD combination therapy by high-throughput gene expression profiling of drug-treated cells. Results: Microarray analysis showed that entinostat and doxorubicin (ED) altered expression of genes related to growth arrest, inflammation, and differentiation. ED downregulated MYC, E2F, and G2M cell cycle genes. Accordingly, entinostat sensitized the cells to doxorubicin-induced growth arrest at G2. ED induced interferon genes, which correlated with breast tumors containing a higher proportion of tumor-infiltrating lymphocytes. ED also increased the expression of immune checkpoint agonists and cancer testis antigens. Analysis of TNBC xenografts showed that EAD enhanced the inflammation score in nude mice. Among the genes differentially regulated between the EAD and ED groups, an all-trans retinoic acid (ATRA)-regulated gene, DHRS3, was induced in EAD-treated xenografts. DHRS3 was expressed at lower levels in human TNBC metastases compared to normal breast or primary tumors. High expression of ED-induced growth arrest and inflammatory genes was associated with better prognosis in TNBC patients. Conclusions: Entinostat potentiated doxorubicin-mediated cell death and the combination induced inflammatory signatures. The ED-induced immunomodulation may improve immunotherapy. Addition of ATRA to ED may potentiate inflammation and contribute to TNBC regression.

Oncogene, 2017

Tumor suppressor and upstream master kinase Liver kinase B1 (LKB1) plays a significant role in su... more Tumor suppressor and upstream master kinase Liver kinase B1 (LKB1) plays a significant role in suppressing cancer growth and metastatic progression. We show that low-LKB1 expression significantly correlates with poor survival outcome in breast cancer. In line with this observation, loss-of-LKB1 rendered breast cancer cells highly migratory and invasive, attaining cancer stem cell-like phenotype. Accordingly, LKB1-null breast cancer cells exhibited an increased ability to form mammospheres and elevated expression of pluripotency-factors (Oct4, Nanog and Sox2),

Oncoscience, 2015

HOXB7 is a homeodomain containing transcription factor which plays a pivotal role in tamoxifen re... more HOXB7 is a homeodomain containing transcription factor which plays a pivotal role in tamoxifen resistant breast cancer. Our work has shown that overexpression of HOXB7 renders cells tamoxifen resistant by mobilizing a number of receptor tyrosine kinase pathways. EGFR expression is upregulated by direct binding of HOXB7 to the EGFR promoter, while HOXB7 functions as a cofactor with ERα to cause overexpression

Theranostics, 2017

Extensive evidence has shown that platelets support tumor metastatic progression by inducing epit... more Extensive evidence has shown that platelets support tumor metastatic progression by inducing epithelial-mesenchymal transition of cancer cells and by shielding circulating tumor cells from immune-mediated elimination. Therefore, blocking platelet function represents a potential new avenue for therapy focused on eliminating metastasis. Here we show that liposomal nanoparticles bearing the tumor-homing pentapeptide CREKA (Cys-Arg-Glu-Lys-Ala) can deliver a platelet inhibitor, ticagrelor, into tumor tissues to specifically inhibit tumor-associated platelets. The drug-loaded nanoparticles (CREKA-Lipo-T) efficiently blocked the platelet-induced acquisition of an invasive phenotype by tumor cells and inhibited platelet-tumor cell interaction in vitro. Intravenously administered CREKA-Lipo-T effectively targeted tumors within 24 h, and inhibited tumor metastasis without overt side effects. Thus, the CREKA-Lipo formulation provides a simple strategy for the efficient delivery of anti-metast...

Oncotarget, 2016

Breast cancer is the most prevalent cancer in women worldwide. About 15-20% of all breast cancers... more Breast cancer is the most prevalent cancer in women worldwide. About 15-20% of all breast cancers do not express estrogen receptor, progesterone receptor or HER2 receptor and hence are collectively classified as triple negative breast cancer (TNBC). These tumors are often relatively aggressive when compared to other types of breast cancer, and this issue is compounded by the lack of effective targeted therapy. In our previous phosphoproteomic profiling effort, we identified the non-receptor tyrosine kinase TNK2 as activated in a majority of aggressive TNBC cell lines. In the current study, we show that high expression of TNK2 in breast cancer cell lines correlates with high proliferation, invasion and colony forming ability. We demonstrate that knockdown of TNK2 expression can substantially suppress the invasiveness and proliferation advantage of TNBC cells in vitro and tumor formation in xenograft mouse models. Moreover, inhibition of TNK2 with small molecule inhibitor (R)-9bMS significantly compromised TNBC proliferation. Finally, we find that high levels of TNK2 expression in high-grade basal-like breast cancers correlates significantly with poorer patient outcome. Taken together, our study suggests that TNK2 is a novel potential therapeutic target for the treatment of TNBC.

Oncotarget, Jan 23, 2016

The standard treatment for ductal carcinoma in situ (DCIS) of the breast is surgical resection, f... more The standard treatment for ductal carcinoma in situ (DCIS) of the breast is surgical resection, followed by radiation. Here, we tested localized therapy of DCIS in mice using the immunoconjugate 225Ac linked-trastuzumab delivered through the intraductal (i.duc) route. Trastuzumab targets HER-2/neu, while the alpha-emitter 225Ac (half-life, 10 days) delivers highly cytotoxic, focused doses of radiation to tumors. Systemic 225Ac, however, elicits hematologic toxicity and at high doses free 213Bi, generated by its decay, causes renal toxicity. I.duc delivery of the radioimmunoconjugate could bypass its systemic toxicity. Bioluminescent imaging showed that the therapeutic efficacy of intraductal 225Ac-trastuzumab (10-40 nCi per mammary gland; 30-120 nCi per mouse) in a DCIS model of human SUM225 cancer cells in NSG mice was significantly higher (p<0.0003) than intravenous (120 nCi per mouse) administration, with no kidney toxicity or loss of body weight. Our findings suggest that i.d...

Molecular cancer therapeutics, Jan 12, 2015

Peptide therapeutics holds great promise for the treatment of cancer due to low toxicity, high sp... more Peptide therapeutics holds great promise for the treatment of cancer due to low toxicity, high specificity, and ease of synthesis and modification. However, the unfavorable pharmacokinetic parameters strictly limit their therapeutic efficacy and clinical translation. Here we tailor-designed an amphiphilic chimeric peptide through conjugation of functional 3-diethylaminopropyl isothiocyanate (DEAP) molecules to a short antitumor peptide, C16Y. The ultimate DEAP-C16Y peptides self-assembled into spherical nanostructures at physiological conditions, which dissociated to release individual peptide molecules in weakly acidic tumors. DEAP-C16Y peptides showed negligible cytotoxicity but impaired vascular endothelial cell migration and tubule formation by inactivation of the focal adhesion kinase and PI3K-Akt pathways, as well as tumor cell invasion by decreasing invadopodia formation. Compared to C16Y, the systemically administered DEAP-C16Y nanostructures exhibited superior stability, th...

Cancer discovery, Jan 15, 2015

Why breast cancers become resistant to tamoxifen despite continued expression of the estrogen rec... more Why breast cancers become resistant to tamoxifen despite continued expression of the estrogen receptor alpha (ERα) and what factors are responsible for high HER2 expression in these tumors remains an enigma. HOXB7 ChIP analysis followed by validation showed that HOXB7 physically interacts with ERα, and that the HOXB7-ERα complex enhances transcription of many ERα target genes including HER2. Investigating strategies for controlling HOXB7, our studies revealed that MYC, stabilized via phosphorylation mediated by EGFR-HER2 signaling, inhibits transcription of miRNA-196a, a HOXB7 repressor. This leads to increased expression of HOXB7, ER-target genes and HER2. Repressing MYC using small molecule inhibitors reverses these events, and causes regression of breast cancer xenografts. The MYC-HOXB7-HER2 signaling pathway is eminently targetable in endocrine-resistant breast cancer.