Investigator
Ludwig Maximilians Universitt Mnchen
Identification of FLYWCH1 as a regulator of platinum-resistance in epithelial ovarian cancer
Abstract Platinum-based combination chemotherapy remains the backbone of first-line treatment for patients with advanced epithelial ovarian cancer (EOC). While most patients initially respond well to the treatment, patients with relapse ultimately develop platinum resistance. This study identified FLYWCH-type zinc finger-containing protein 1 (FLYWCH1) as an important regulator in the resistance development process. We showed that the loss of FLYWCH1 promotes platinum resistance in EOC cells, and the low FLYWCH1 expression is correlated with poor prognosis of EOC patients. In platinum-sensitive cells, FLYWCH1 colocalizes with H3K9me3, but this association is significantly reduced when cells acquire resistance. The suppression of FLYWCH1 induces gene expression changes resulting in the deregulation of pathways associated with resistance. In line with its connection to H3K9me3, FLYWCH1 induces gene silencing in a synthetic reporter assay and the suppression of FLYWCH1 alters H3K9me3 at promoter regions and repeat elements. The loss of FLYWCH1 leads to the derepression of LTR and Alu repeats, thereby increasing transcriptional plasticity and driving the resistance development process. Our data highlight the importance of FLYWCH1 in chromatin biology and acquisition of platinum resistance through transcriptional plasticity and propose FLYWCH1 as a potential biomarker for predicting treatment responses in EOC patients.
Expression of Intracellular Galectin-8 and -9 in Endometrial Cancer
Endometrial cancer (EC) is a common gynecological cancer worldwide. Treatment has been improved in recent years; however, in advanced stages, therapeutic options are still limited. The expression of galectins is increased in several tumor types and that they are involved in important cell processes. Large studies on endometrial cancer are still pending; Specimens of 225 patients with EC were immunohistochemically stained with antibodies for Gal-8 and Gal-9. Expression was correlated with histopathological variables. The cytosolic expression of both galectins is associated with grading and survival. Cytosolic Galectin-8 expression is a positive prognostic factor for overall survival (OS) and progression-free survival (PFS), while nuclear Gal-8 expression correlates only to OS. The cytosolic presence of Galectin-9 is correlated with a better prognosis regarding OS. Our results suggest that expression of both galectins is associated with OS and PFS in EC. Further studies are needed to understand the underlying molecular mechanisms.
Protocol to optimize the biobanking of ovarian cancer organoids by accommodating patient-specific differences in stemness potential
We present a protocol for effective biobanking of epithelial ovarian cancer organoids, considering the heterogeneous clinical presentation and high recurrence rates. Our protocol involves parallel testing of three media to identify patient-specific optimal conditions. We describe steps for tissue dissociation, differential seeding, organoid cultivation, and biobanking. We outline procedures for fixation, embedding, and staining for confocal imaging. Furthermore, we demonstrate that brief cultivation of isolates in 2D on plastic enhances organoid-forming potential in selected lines, expanding their application scope. For complete details on the use and execution of this protocol, please refer to Hoffmann et al.
Stable expansion of high‐grade serous ovarian cancer organoids requires a low‐Wnt environment
High-grade serous ovarian cancer (HGSOC) likely originates from the fallopian tube (FT) epithelium. Here, we established 15 organoid lines from HGSOC primary tumor deposits that closely match the mutational profile and phenotype of the parental tumor. We found that Wnt pathway activation leads to growth arrest of these cancer organoids. Moreover, active BMP signaling is almost always required for the generation of HGSOC organoids, while healthy fallopian tube organoids depend on BMP suppression by Noggin. Fallopian tube organoids modified by stable shRNA knockdown of p53, PTEN, and retinoblastoma protein (RB) also require a low-Wnt environment for long-term growth, while fallopian tube organoid medium triggers growth arrest. Thus, early changes in the stem cell niche environment are needed to support outgrowth of these genetically altered cells. Indeed, comparative analysis of gene expression pattern and phenotypes of normal vs. loss-of-function organoids confirmed that depletion of tumor suppressors triggers changes in the regulation of stemness and differentiation.
