Towards a Science of Tumor Forecasting for Clinical Oncology

We propose that the quantitative cancer biology community make a concerted effort to apply lessons from weather forecasting to develop an analogous methodology for predicting and evaluating tumor growth and treatment response. Currently, the time course of tumor response is not predicted; instead, response is- only assessed post hoc by physical exam or imaging methods. This fundamental practice within clinical oncology limits optimization of atreatment regimen for an individual patient, as well as to determine in real time whether the choice was in fact appropriate. This is especially frustrating at a time when a panoply of molecularly targeted therapies is available, and precision genetic or proteomic analyses of tumors are an established reality. By learning from the methods of weather and climate modeling, we submit that the forecasting power of biophysical and biomathematical modeling can be harnessed to hasten the arrival of a field of predictive oncology. With a successful methodology towards tumor forecasting, it should be possible to integrate large tumor specific datasets of varied types, and effectively defeat cancer one patient at a time.

Role of SSB1 for TERT Recruitment

Proliferating mammalian stem and cancer cells express telomerase [telomerase reverse transcriptase (TERT)] in an effort to extend chromosomal G-overhangs and maintain telomere ends. Telomerase-expressing cells also have higher levels of the single-stranded DNA-binding protein SSB1, which has a critical role in DNA double-strand break (DSB) repair. Here, we report that SSB1 binds specifically to G-strand telomeric DNA in vitro and associates with telomeres in vivo. SSB1 interacts with the TERT catalytic subunit and regulates its interaction with telomeres. Deletion of SSB1 reduces TERT interaction with telomeres and leads to G-overhang loss. Although SSB1 is recruited to DSB sites, we found no corresponding change in TERT levels at these sites, implying that SSB1–TERT interaction relies upon a specific chromatin structure or context. Our findings offer an explanation for how telomerase is recruited to telomeres to facilitate G-strand DNA extension, a critical step in maintaining telomere ends and cell viability in all cancer cells. Cancer Res; 75(5); 1–12. ©2015 AACR.

Single-strand DNA binding protein SSB1 acilitates TERT recruitment to telomeres and maintains telomere G-overhangs

Proliferating mammalian stem and cancer cells express telomerase (TERT) in an effort to extend chromosomal G-overhangs and maintain telomere ends. Telomerase-expressing cells also have higher levels of the single-stranded DNA binding protein SSB1, which has a critical role in DNA double-strand break repair. Here we report that SSB1 binds specifically to G-strand telomeric DNA in vitro and associates with telomeres in vivo. SSB1 interacted with the TERT catalytic subunit and regulates its interaction with telomeres. Deletion of SSB1 reduced TERT interaction with telomeres and led to G-overhang loss. While SSB1 was recruited to DSB sites, we found no corresponding change in TERT levels at these sites, implying that SSB1-TERT interaction relied upon a specific chromatin structure or context. Our findings offer an explanation for how telomerase is recruited to telomeres to facilitate G-strand DNA extension, a critical step in maintaining telomere ends and cell viability in all cancer cells.

Next-Generation Omics in Head and Neck Cancer

Head and neck squamous cell carcinoma (HNSCC) is a highly heterogeneous disease that develops via one of the two primary carcinogenic routes: chemical carcinogenesis through exposure to tobacco and alcohol or virally induced tumorigenesis. Human papillomavirus (HPV)–positive (HPV+) and HPV-negative (HPV−) HNSCCs represent distinct clinical entities, with the latter associated with significantly inferior outcome. The biologic basis of these different outcomes is an area of intense investigation; their therapeutic regimens are currently also being reevaluated, which would be significantly facilitated by reliable biomarkers for stratification. With the advent of the omics era and accelerated development of targeted therapies, there are unprecedented opportunities to address the challenges in the management of HNSCC. As summarized herein, side-by-side molecular characterization of HPV+ versus HPV− HNSCC has revealed distinct molecular landscapes, novel prognostic signatures, and potentially targetable biologic pathways. In particular, we focus on the evidence acquired from genome-wide omics pertinent to our understanding of the clinical behavior of HNSCC and on insights into personalized treatment opportunities. Integrating, mining, and validating these data toward clinically meaningful outcomes for patients with HNSCC in conjunction with systematic verification of the functional relevance of these findings are critical steps toward the design of personalized therapies. Cancer Res; 75(3); 1–7. ©2014 AACR.

Th9 Cells and Cancer

CD4 T cells are key components of the immune system that shape the anticancer immune response in animal models and in humans. The biology of CD4 T cells is complex because naïve T cells can differentiate into various subpopulations with various functions. Recently, a new population called Th9 cells was described. These cells are characterized by their ability to produce IL9 and IL21. They were first described in the context of parasite infections and allergic processes. However, some reports described their presence in the tumor bed in mice and humans. Their high secretion of IL9 and IL21 in the tumor bed contributes to their anticancer functions. Indeed, these cytokines trigger the activation of dendritic cells, mast cells, natural killer cells, and CD8 T cells to mount an antitumor immune response, thus explaining the remarkable ability of Th9 cells to control tumor growth. This review summarizes the latest advances in the Th9 field in cancer and focuses on their potential role as new tool for cell therapy. Cancer Res; 75(3); 1–5. ©2014 AACR.