Peripheral blood MФ–cancer cell fusion hybrids identified in cancer patients correlate with disease stage and overall survival.

Christina Curtis and colleagues simulate spatial tumor growth under different evolutionary models and compare their results to multiregion sequencing data. They find that it is possible to distinguish tumors driven by strong positive selection from those evolving neutrally or under weak selection and infer different evolutionary modes within and between tumor types. Given the implications of tumor dynamics for precision medicine, there is a need to systematically characterize the mode of evolution across diverse solid tumor types. In particular, methods to infer the role of natural selection within established human tumors are lacking. By simulating spatial tumor growth under different evolutionary modes and examining patterns of between-region subclonal genetic divergence from multiregion sequencing (MRS) data, we demonstrate that it is feasible to distinguish tumors driven by strong positive subclonal selection from those evolving neutrally or under weak selection, as the latter fail to dramatically alter subclonal composition. We developed a classifier based on measures of between-region subclonal genetic divergence and projected patient data into model space, finding different modes of evolution both within and between solid tumor types. Our findings have broad implications for how human tumors progress, how they accumulate intratumoral heterogeneity, and ultimately how they may be more effectively treated.

Pancreatic ductal adenocarcinoma (PDAC) is among the top causes of cancer-related death. Patients are frequently diagnosed in the more advanced stages when effective treatment options are limited; however, earlier detection of PDAC by liquid biopsy may expand treatment options and improve survival outcomes. Here, we developed a noninvasive detection assay for PDAC based on serum protease activity to leverage the increase in cancer-associated protease activity in the peripheral blood of patients with PDAC. We screened a series of protease-cleavable peptide probes for the discrimination of PDAC samples versus healthy controls and noncancerous pancreatic disease. We identified a single MMP-sensitive probe, which could distinguish PDAC from controls with 79 ± 6% accuracy. We further developed this probe into a rapid magnetic nanosensor assay, termed PAC-MANN, that measures serum protease cleavage of a target-probe nanosensor with a simple fluorescent readout. In a longitudinal cohort of patients undergoing surgical removal of the primary tumor, the probe cleavage signal was reduced by 16 ± 24% after surgery. In a separate blinded retrospective study, the PAC-MANN assay identified PDAC samples with 98% specificity and 73% sensitivity across all stages and distinguished 100% of patients with noncancer pancreatic disease relative to patients with PDAC. The PAC-MANN assay combined with the clinical biomarker CA 19-9 was 85% sensitive for detection of stage I PDAC with 96% specificity. Therefore, the PAC-MANN assay is a rapid, high-throughput method that uses small blood volumes with the potential to enhance early PDAC detection, specifically among individuals at high risk of developing PDAC.

Senescent cells accumulate in tissues over time as part of the natural ageing process and the removal of senescent cells has shown promise for alleviating many different age-related diseases in mice. Cancer is an age-associated disease and there are numerous mechanisms driving cellular senescence in cancer that can be detrimental to recovery. Thus, it would be beneficial to develop a senolytic that acts not only on ageing cells but also senescent cancer cells to prevent cancer recurrence or progression. We used molecular modelling to develop a series of rationally designed peptides to mimic and target FOXO4 disrupting the FOXO4-TP53 interaction and releasing TP53 to induce apoptosis. We then tested these peptides as senolytic agents for the elimination of senescent cells both in cell culture and in vivo. Here we show that these peptides can act as senolytics for eliminating senescent human cancer cells both in cell culture and in orthotopic mouse models. We then further characterized one peptide, ES2, showing that it disrupts FOXO4-TP53 foci, activates TP53 mediated apoptosis and preferentially binds FOXO4 compared to TP53. Next, we show that intratumoural delivery of ES2 plus a BRAF inhibitor results in a significant increase in apoptosis and a survival advantage in mouse models of melanoma. Finally, we show that repeated systemic delivery of ES2 to older mice results in reduced senescent cell numbers in the liver with minimal toxicity. Taken together, our results reveal that peptides can be generated to specifically target and eliminate FOXO4+ senescent cancer cells, which has implications for eradicating residual disease and as a combination therapy for frontline treatment of cancer. This work was supported by the Cancer Early Detection Advanced Research Center at Oregon Health & Science University.

Although Apc mutation is widely considered an initiating event in colorectal cancer, little is known about the earliest stages of tumorigenesis following sporadic Apc loss. Therefore, we have utilized a novel mouse model that facilitates the sporadic inactivation of Apc via frameshift reversion of Cre in single, isolated cells and subsequently tracks the fates of Apc-deficient intestinal cells. Our results suggest that consistent with Apc being a ‘gatekeeper’, loss of Apc early in life during intestinal growth leads to adenomas or increased crypt fission, manifested by fields of mutant but otherwise normal-appearing crypts. In contrast, Apc loss occurring later in life has minimal consequences, with mutant crypts being less prone to either increased crypt fission or adenoma formation. Using the stem cell-specific Lgr5-CreER mouse, we generated different sized fields of Apc-deficient crypts via independent recombination events and found that field size correlates with progression to adenoma. To evaluate this early stage prior to adenoma formation as a therapeutic target, we examined the chemopreventive effects of sulindac on Apc-deficient occult crypt fission. We found that sulindac treatment started early in life inhibits the morphologically occult spread of Apc-deficient crypts and thus reduces adenoma numbers. Taken together these results suggest that: (i) earlier Apc loss promotes increased crypt fission, (ii) a field of Apc-deficient crypts, which can form via occult crypt fission or independent neighboring events, is an important intermediate between loss of Apc and adenoma formation and (iii) normal-appearing Apc-deficient crypts are potential unappreciated targets for cancer screening and chemoprevention.