A Platform of Patient-Derived Microtumors Identifies Individual Treatment Responses and Therapeutic Vulnerabilities in Ovarian Cancer

Abstract

In light of the frequent development of therapeutic resistance in cancer treatment, there is a strong need for personalized model systems representing patient tumor heterogeneity, while enabling parallel drug testing and identification of appropriate treatment responses in individual patients. Using ovarian cancer as a prime example of a heterogeneous tumor disease, we developed a 3D preclinical tumor model comprised of patient-derived microtumors (PDM) and autologous tumor-infiltrating lymphocytes (TILs) to identify individual treatment vulnerabilities and validate chemo-, immuno- and targeted therapy efficacies. Enzymatic digestion of primary ovarian cancer tissue and cultivation in defined serum-free media allowed rapid and efficient recovery of PDM, while preserving histopathological features of corresponding patient tumor tissue. Reverse-phase protein array (RPPA)-analyses of >110 total and phospho-proteins enabled the identification of patient-specific sensitivities to standard, platinum-based therapy and thereby the prediction of potential treatment-responders. Co-cultures of PDM and autologous TILs for individual efficacy testing of immune checkpoint inhibitor treatment demonstrated patient-specific enhancement of cytotoxic TIL activity by this therapeutic approach. Combining protein pathway analysis and drug efficacy testing of PDM enables drug mode-of-action analyses and therapeutic sensitivity prediction within a clinically relevant time frame after surgery. Follow-up studies in larger cohorts are currently under way to further evaluate the applicability of this platform to support clinical decision making.

Co-cultures of iPSC-derived Mammary-like Organoids and Patient-derived Microtumors Model Invasive Behavior of Breast Cancer ex vivo

“…At the same time, these effects could not be observed in spheroids derived from the non-metastatic MCF-7 cell line and in PDMs from BCP 2 and BCP 3. Unlike primary cancer cells or immortalized cells lines, PDMs are not composed of a homogenous culture of neoplastic cells but consist of diverse cell types and stromal components re ecting the heterogeneous nature and composition of primary patient tumors [17][18][19][20]. The tumor specimens used in our study can be listed according to their malignant progression in descending order: BCP 1 was diagnosed with a stage III IDC-NST.…”

“…Isolation and cultivation of PDMs was performed as previously described [17][18][19][20]. In brief, primary tumor tissue (PTT) was mechanically dissected with a scalpel and a forceps into 1-2 mm fragments.…”

“…To better understand breast cancer's invasive properties and interaction with the TME, it is crucial to use cancer models that re ect this diverse nature of breast carcinomas. We previously introduced the isolation of ovarian and brain microtumors from primary tumor tissue (PTT) and described the heterogenous nature of PDMs and their functionality in compound testing [17][18][19]. Here, we transferred this knowledge to breast cancer lesions and isolated breast microtumors from primary breast tumor tissue.…”

“…Here, we differentiated the iPSCs into functional MLOs expressing markers of the mammary epithelium and myoepithelium. We describe the isolation of breast cancer patient-derived microtumors (PDMs) -small tumor fragments isolated from residual fresh primary breast tumor tissue that re ect the heterogeneous nature of tumors [17][18][19][20]. The co-culture of breast cancer spheres and MLOs led to a signi cant upregulation of two crucial prognostic markers, FN and Metalloproteinase-2 (MMP2), known to be associated with invasive and metastatic tumor phenotypes and a poor prognosis for breast cancer patients [21,22].…”

Breast cancer patient-derived microtumors resemble tumor heterogeneity and enable protein-based stratification and functional validation of individualized drug treatment

“…Fresh dissected breast tumor tissues were transported within DMEM/F12 culture media (Gibco) and subsequently processed as previously described (2022) (21). The isolation of patient-derived microtumors was adapted from Kondo et al (22).…”