Publications

Journal Publications

August 12, 2019
S. Uttam, J. G. Hashash, J. LaFace, D. Binion, M. Regueiro, D. J. Hartman, R. E. Brand, and Y. Liu
Abstract

Patients with inflammatory bowel disease (IBD) colitis are at an increased risk of developing colorectal cancer and are currently recommended to undergo extensive annual or biennial colonoscopy, a costly and invasive procedure. Most surveillance colonoscopies are negative with no existing objective measures for assessing their risk of developing cancer. We have recently developed a less invasive, cost-effective and objective method to assess cancer risk by detecting the presence of colonic neoplasia via 3-dimensional (3D) nanoscale nuclear architecture mapping (nanoNAM) of normal-appearing rectal biopsies. To establish its translational relevance, we prospectively recruited 103 patients with IBD colitis undergoing surveillance colonoscopy and measured submicroscopic alterations in aberrant intrinsic nuclear architecture of epithelial cells from normal-appearing rectal biopsies with nanoNAM. The results were correlated with the histologic diagnoses from all random biopsies obtained during initial and follow-up colonoscopy within 3 years. Using nanoNAM-based structural characterization as input features into a soft margin-based ν-SVM risk classifier, we show that nanoNAM detects colonic neoplasia with AUC of 0.87 ± 0.04, sensitivity of 0.81 ± 0.09, and specificity of 0.82 ± 0.07 in the independent validation set. In addition, projecting nanoNAM features onto a 2-sphere reveals patients with low-risk and high-risk IBD colitis existing on separate hemispheres. Finally, we show that this ability to assess cancer risk translates to clinically-relevant estimation of individual-patient likelihood of being truly at risk. We demonstrate the potential of nanoNAM to identify patients with IBD at higher risk of developing cancer from normal-appearing rectum tissue, which may aid clinicians in patients with personalized IBD colitis surveillance

July 11, 2019
E. Fouquerel, R. Barnes, S. Uttam, S. Watkins, M. Bruchez, and P. L. Opresko
Abstract

Telomeres are essential for genome stability. Oxidative stress caused by excess reactive oxygen species (ROS) accelerates telomere shortening. Although telomeres are hypersensitive to ROS-mediated 8-oxoguanine (8-oxoG) formation, the biological effect of this common lesion at telomeres is poorly understood because ROS have pleiotropic effects. Here we developed a chemoptogenetic tool that selectively produces 8-oxoG only at telomeres. Acute telomeric 8-oxoG formation increased telomere fragility in cells lacking OGG1, the enzyme that removes 8-oxoG, but did not compromise cell survival. However, chronic telomeric 8-oxoG induction over time shortens telomeres and impairs cell growth. Accumulation of telomeric 8-oxoG in chronically exposed OGG1-deficient cells triggers replication stress, as evidenced by mitotic DNA synthesis at telomeres, and significantly increases telomere losses. These losses generate chromosome fusions, leading to chromatin bridges and micronucleus formation upon cell division. By confining base damage to the telomeres, we show that telomeric 8-oxoG accumulation directly drives telomere crisis.

July 24, 2018
J. Xu, H. Ma, J. Jin, S. Uttam, R. Fu, Y. Huang, and Y. Liu
Abstract

Histone modifications influence higher-order chromatin structures at individual epigenomic states and chromatin environments to regulate gene expression. However, genome-wide higher-order chromatin structures shaped by different histone modifications remain poorly characterized. With stochastic optical reconstruction microscopy (STORM), we characterized the higher-order chromatin structures at their epigenomic states, categorized into three major types in interphase: histone acetylation marks form spatially segregated nanoclusters, active histone methylation marks form spatially dispersed larger nanodomains, and repressive histone methylation marks form condensed large aggregates. These distinct structural characteristics are also observed in mitotic chromosomes. Furthermore, active histone marks coincide with less compact chromatin and exhibit a higher degree of co-localization with other active marks and RNA polymerase II (RNAP II), while repressive marks coincide with densely packed chromatin and spatially distant from repressive marks and active RNAP II. Taken together, super-resolution imaging reveals three distinct chromatin structures at various epigenomic states, which may be spatially coordinated to impact transcription.

March 1, 2018
S. Uttam and Y. Liu
Abstract

Quantitative phase imaging (QPI) modality has been widely adopted in a variety of applications ranging from identifying photomask defects in lithography to characterizing cell structure and tissue morphology in cancer. Traditional QPI utilizes the electromagnetic phase of transmitted light to measure, with nanometer scale sensitivity, alterations in the optical thickness of a sample of interest. In our work, the QPI paradigm is generalized to study depth-resolved properties of phase objects with slowly varying refractive index without a strong interface by utilizing the Fourier phase associated with Fourier-domain optical coherence tomography (FD-OCT). Specifically, based on computing the Fourier phase of light back-scattered by cell nuclei, we have developed nanoscale nuclear architecture mapping (nanoNAM) method that quantifies, with nanoscale sensitivity, (a) the depth-resolved alterations in mean nuclear optical density, and (b) depth-resolved localized heterogeneity in optical density of the cell nuclei. We have used nanoNAM to detect malignant transformation in colon carcinogenesis, even in tissue that appears histologically normal according to pathologists, thereby showing its potential as a pathology aid in cases where pathology examination remains inconclusive, and for screening patient populations at risk of developing cancer. In this paper, we integrate all aspects of nanoNAM, from principle through instrumentation and analysis, to show that nanoNAM is a promising, low-cost, and label-free method for identifying pathologically indeterminate pre-cancerous and cancerous cells. Importantly, it can seamlessly integrate into the clinical pipeline by utilizing clinically prepared formalin-fixed, paraffin-embedded tissue sections.

November 10, 2015
J. Opt. Soc. Am. A; 32: 2286-2306 (2015).
Fourier phase in Fourier-domain optical coherence tomography
S. Uttam and Y. Liu
Abstract

Phase of an electromagnetic wave propagating through a sample-of-interest is well understood in the context of quantitative phase imaging in transmission-mode microscopy. In the past decade, Fourier-domain optical coherence tomography has been used to extend quantitative phase imaging to the reflection-mode. Unlike transmission-mode electromagnetic phase, however, the origin and characteristics of reflection-mode Fourier phase are poorly understood, especially in samples with a slowly varying refractive index. In this paper, the general theory of Fourier phase from first principles is presented, and it is shown that Fourier phase is a joint estimate of subresolution offset and mean spatial frequency of the coherence-gated sample refractive index. It is also shown that both spectral-domain phase microscopy and depth-resolved spatial-domain low-coherence quantitative phase microscopy are special cases of this general theory. Analytical expressions are provided for both, and simulations are presented to explain and support the theoretical results. These results are further used to show how Fourier phase allows the estimation of an axial mean spatial frequency profile of the sample, along with depth-resolved characterization of localized optical density change and sample heterogeneity. Finally, a Fourier phase-based explanation of Doppler optical coherence tomography is also provided.

Conference Presentations

D. Brokl, D. Lo, W. Khalbuss, P. Wang, R. Bista, S. Uttam, Y. Liu, and R. Brand
Spatial-Domain Low-Coherence Quantitative Phase Microscopy to Improve the Cytological Diagnosis of Pancreatic Cancer
Gastroenterology - Orlando, 2011; 140(1):S-53. [Plenary talk]
May 1, 2011
S. Uttam, J. Xu, and Y. Liu
Nanoscale nuclear architecture mapping captures chromatin reorganization in epithelial cells undergoing malignant transformation
SPIE Photonics West (BIOS), 6-11 March 2021, San Francisco, USA; Conference Proceedings volume 11653, Quantitative Phase Imaging VII; 1165318 (2021).
March 6, 2011
S. Uttam, N. Goodman, and M. Neifeld
Direct reconstruction of difference images from optimal spatial-domain projections
in Proc. SPIE Conference on Optics & Photonics, San Diego, CA, Aug. 2008.
August 1, 2008
S. Uttam, N. Goodman, M. Neifeld, D. Brady, J. Kim, and C. Kim
Optically multiplexed imaging with superposition-space tracking
in Proc. SPIE Conference on Optics & Photonics, San Diego, CA, Aug. 2008.
August 1, 2008
S. Uttam, N. Goodman, and M. Neifeld
Difference imaging from linear spatial-domain projections
SIAM Conference on Imaging Science, San Diego, CA July 2008
July 1, 2008

Conference Presentations

S. Uttam
Nanoscale nuclear architecture mapping of early carcinogenesis
Paper 12389-32, Quantitative Phase Imaging IX, SPIE Photonics West, San Francisco (January 27 - Feb 1, 2023) [Invited]
February 1, 2023
S. Uttam
Label-free nanoscale nuclear architecture mapping of early carcinogenesis
2023 Biophysics and Quantitative Biology in the AI Era, NSF AI Planning Institute at Carnegie Mellon University (Jan 12-13, 2023)
January 25, 2023
S. Uttam
Overcoming the segmentation barrier in in multiplexed spatial proteomic images
UPMC Hillman Cancer Center, Spatial Omics and Computational Imaging in Human Diseases Symposium, Nov 14, 2022. [Invited]
December 1, 2022
S. Uttam
Cancer systems biology in space and scale
UPMC Hillman Cancer Center, Cancer Biology Program Retreat, Oct 24, 2022 [Invited]
November 20, 2022
B. Raymond, D. J. Hartman, and S. Uttam
Spatial Analysis of Cytotoxic T Lymphocyte Infiltration in Colorectal Tumors for Predicting Stage-independent Relapse and Death
2022 Biomedical Engineering Society (BMES) Annual Meeting, Oct 12-15, 2022
October 1, 2022
C. Newman, B. Kochetov, R. Raphael, L. Zhang, and S. Uttam
Understanding the Cellular Landscape of Preclinical Models of Colorectal Cancer
2022 Biomedical Engineering Society (BMES) Annual Meeting, Oct 12-15, 2022
October 1, 2022
K. Yadav, R. Pawar, A. Singhi, and S. Uttam
Characterizing the Three-Dimensional Nuclear Morphology of Normal Appearing, Immune, and Cancer Cells in Cancer Tumor Microenvironment
2022 Biomedical Engineering Society (BMES) Annual Meeting, Oct 12-15, 2022
October 1, 2022
P. N. Thota, J. Nasibli, P. Kumar, M.R. Sanaka, A. Chak, X. Zhang, X. Liu, S. Uttam, and Y. Liu
Nanoscale nuclear architecture mapping predicts neoplastic progression in Barrett’s esophagus: a proof-of-concept study
in Gastrointest. Endosc.; 95(6) Supplement, AB230-AB231
September 1, 2022
B. Kochetov, P.D. Bell, R. Raphael, B.J. Raymond, B.J. Leibowitz, J. Tong, B. Diergaarde , J. Yu, R.K. Pai, R.E. Schoen, L. Zhang, A. Singhi, and S. Uttam
Unsupervised sub-cellular segmentation of complex tissue and cell samples using highly multiplexed imaging-derived a priori knowledge
Abstract 1930. Cancer Res 15 June 2022; 82 (12_Supplement): 1930
June 1, 2022
B. Kochetov, R. Raphael, and S. Uttam
Unsupervised segmentation of complex tissue using multiplexed imaging-derived a priori knowledge
Biomedical Engineering Society (BMES) 2021 Annual Meeting; Oct 6 - 9, 2021; Orlando, Florida; Abstract 074 - 841 (2021)
October 6, 2021
S. Leng, J. Xu, Y. Liu, and S. Uttam
Demonstration of ability of nanoscale nuclear architecture mapping to study chromatin alteration
Biomedical Engineering Society (BMES) 2021 Annual Meeting; Oct 6 - 9, 2021; Orlando, Florida; Abstract reu-011-3129 (2021).
October 6, 2021
D. Pitlor, R. E. Brand, B. Dudley, E. Karlowski, A. Zyhowski, E. J. Metter, R. M. Brand, and S. Uttam
Coefficient of variation based multiplexed ELISA biomarker selection in HNPCC Syndrome Patients
Biomedical Engineering Society (BMES) 2021 Annual Meeting; Oct 6 - 9, 2021; Orlando, Florida; Abstract reu-007-3147 (2021)
October 6, 2021
S. Uttam
Sampling and scrambling in compressive sensing based spectral domain optical coherence tomography
CLEO Laser Science to Photonic Applications (Optical Society of America, 2020) JTu2F.7.
May 10, 2020
S. Uttam and Y. Liu
Three-dimensional nanoscale nuclear architecture mapping for improved cancer risk stratification
SPIE/OSA European Conferences on Biomedical Optics (ECBO) 2019, 23-27 June 2019, Munich, Germany; Paper 11076-38 (2019). [Invited paper]
June 23, 2019
S. Uttam, A.M. Stern, S. A. Furman, F. Pullara, F. Ginty, D. L. Taylor, S. C. Chennubhotla
Spatial proteomics with hyperplexed fluorescence imaging predicts risk of colorectal cancer recurrence and infers recurrence-specific protein-protein networks
Cancer Res; 79 (13 Supplement): 1642 (2019). [AACR Annual Meeting 2019, March 29-April 3 2019, Atlanta, Georgia.]
March 29, 2019
S. Uttam
Hyperplexed immunofluorescence imaging based on spatial proteomics predicts risk of colorectal cancer recurrence and infers recurrence-specific protein networks
Joint Immunology and Computational and Systems Biology Workshop, Jan 23, 2019, University of Pittsburgh, Pittsburgh, PA, USA (2019
January 23, 2019
R. C. Burgess and S. Uttam
Modeling the impact of chromatin modifications on the DNA damage response in yeast
Find Your Inner Modeler workshop, Aug 16-17, 2018, University of Illinois at Chicago, Chicago, Illinois, USA (2018). [Travel award]
August 16, 2018
F. Pullara, N. Bouhenni, S. Uttam, and S. C. Chennubhotla
Integrative strategies for probing energy landscapes and dynamics of IDPs
Workshop on Intrinsically Disordered Proteins, TSRC 2017, July 11--14, 2017; Telluride, Colorado, USA (2017)
July 11, 2017
S. Uttam, F. Pullara, and S. C. Chennubhotla
Comparative dynamics - An information theoretic perspective
Biomolecular Machines Conference - Protein Flexibility and Allostery, May 18-21, 2017, Banff, Alberta, Canada (2017)
May 17, 2017
S. Uttam
Nanoscale nuclear architecture mapping for cancer-risk stratification and prediction
Computational Pathology Lecture Series, April 14, 2017; Computational Pathology Interest Group and Lecture Series, University of Pittsburgh, Pittsburgh, Pennsylvania, USA (2017). [Invited talk]
April 17, 2017
Y. Liu, S. Uttam, H. V. Pham, and D. J. Hartman
Improved cancer risk stratification and diagnosis via quantitative phase microscopy
SPIE Photonics West (BIOS), Jan 28 -- Feb 2, 2017, San Francisco, USA; Conference: Quantitative Phase Imaging III, Paper 10074-40 (2017).[Invited paper]
February 2, 2017
R. Bista, S. Uttam, D. Hartman, W. Qiu, J. Yu, L. Zhang, R. Brand, and Y. Liu
Investigation of nuclear nano-morphology markers as a novel biomarker for cancer risk assessment using a mouse model
Gastroenterology - San Diego, 2012; 142(5):S-532.
May 1, 2012
S. Uttam, S. Alexandrov, R. Bista, and Y. Liu
Model-based demonstration of spectral tomographic imaging
in Biomedical Optics, OSA Technical Digest (Optical Society of America, 2012), paper BSu3A.61.
February 28, 2012
Y. Liu, S. Alexandrov, S. Uttam, and R. Bista
Probing Cell Nanoscale Structural Properties Using Intrinsic Contrast of Light Scattering
Biophysical Journal, Vol. 102, Issue 3, S1 (2012). [Invited talk ]
February 25, 2012
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