Investigator
Southern Illinois University School Of Medicine
The role of Piezo1 mechanotransduction in high-grade serous ovarian cancer: Insights from an in vitro model of collective detachment
Slowing peritoneal spread in high-grade serous ovarian cancer (HGSOC) would improve patient prognosis and quality of life. HGSOC spreads when single cells and spheroids detach, float through the peritoneal fluid and take over new sites, with spheroids thought to be more aggressive than single cells. Using our in vitro model of spheroid collective detachment, we determine that increased substrate stiffness led to the detachment of more spheroids. We identified a mechanism where Piezo1 activity increased MMP-1/MMP-10, decreased collagen I and fibronectin, and increased spheroid detachment. Piezo1 expression was confirmed in omental masses from patients with stage III/IV HGSOC. Using OV90 and CRISPR-modified PIEZO1 −/− OV90 in a mouse xenograft model, we determined that while both genotypes efficiently took over the omentum, loss of Piezo1 significantly decreased ascitic volume, tumor spheroids in the ascites, and the number of macroscopic tumors in the mesentery. These results support that slowing collective detachment may benefit patients and identify Piezo1 as a potential therapeutic target.
Reduced cervical sampling of hysterectomy specimens with negative margins on conization: An opportunity to improve resource utilization
Abstract Objectives The current recommendation for hysterectomy specimens performed for cervical cancer following conization is that the entire cervix be submitted for histologic examination. Given the high cost of medical procedures and concerns regarding difficulties with laboratory staffing, we sought to evaluate the potential for selective histologic examination in this setting. Methods Post-conization hysterectomy cases were reviewed for the presence of residual disease in relation to the findings of the prior conization, with consideration of margin status. Residual disease was then assessed for clinical significance. The number of submitted blocks was recorded and the associated costs were estimated. Results Among 32 cases with invasive carcinoma, only cases with margins positive for invasive carcinoma on the conization specimen had residual invasion in the hysterectomy (n = 7), and there were no upgrades due to subtle microscopic disease; 1 case had a change in pathologic stage from pT1b1 to pT2b due to parametrial involvement in the setting of a grossly apparent lesion. Among 20 cases performed following a diagnosis of dysplasia, none were upgraded to invasive carcinoma. Based on protocol-based submission of the entire cervix, 16 blocks of cervix were submitted on average (range, 4-41). Conclusions We estimate that representative sections from each cervical quadrant would save approximately 2 work hours for laboratory staff per case and up to 6 hours for larger cases, reducing costs for the laboratory accordingly. Selective cervical sampling in the setting of negative margins on conization provides an opportunity for improved resource utilization without compromising patient care; as this is a small study, confirmation of these findings in a larger number of cases may be warranted. Additional studies are necessary to determine what other contexts in surgical pathology could benefit from a similar reductive approach.
Collagen fiber density observed in metastatic ovarian cancer promotes tumor cell adhesion
Collagen type I, a key structural component of the extracellular matrix (ECM), is frequently altered in cancer, with altered fiber organization at the primary tumor site linked to metastasis and poor patient outcomes. Here, we demonstrate that collagen fibers are also altered in metastatic sites such as the omentum of patients with high-grade serous ovarian cancer (HGSOC). Specifically, we observed a significant increase in fiber density, alignment, and width. To determine if the increase in fiber density supports metastasis, we used a semi-interpenetrating methacrylated gelatin (gelMA) network in combination with increasing fibrillar collagen. Cancer cells had significantly increased adhesion as collagen fiber density increased. To determine the responsible mechanisms, we used orthogonal systems to examine 1) the different adhesion peptides exposed in collagen (GFOGER) and gelatin (RGD), and 2) the physical structure of fibers. Cells had minimal response to GFOGER, either alone or in combination with RGD, suggesting that increased adhesion did not result from this collagen-specific interaction. Cell adhesion was significantly higher on electrospun PCL-gelatin fibers compared to flat PCL-gelatin substrates, suggesting that increased cell adhesion resulted from fiber structure. We next investigated the cellular mechanisms involved in increased adhesion on gelMA/coll and found that actin polymerization, but not myosin II contractility, was needed. We further demonstrated that cells on fibrous gels had more robust actin polymerization, and that this resulted in greater adhesion strength. Combined, these results suggest that the increase in collagen fibers with tumor metastasis will support the development of additional metastases. STATEMENT OF SIGNIFICANCE: This work advances the evaluation of the matrisome of the omentum, the most common metastatic site in advanced ovarian cancer by characterizing how collagen fibers change with disease progression. To examine the effect of collagen fibers on metastasis, we utilized a suite of in vitro biomaterials to identify a novel role for collagen fibers in supporting cell adhesion through increased actin dynamics during nascent adhesion formation, which results in increased adhesion strength at later times.
