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Harwalkar, K.

Publications and source records attributed to Harwalkar, K..

3 recordsLinked to original sources

Modeling High-grade serous ovarian carcinoma using a combination of in vivo electroporation and CRISPR/Cas9 mediated genome editing

Ovarian cancer remains the most lethal gynecological cancer today. High-grade serous ovarian carcinoma (HGSC) is the most common and lethal type of ovarian cancer and is most frequently diagnosed at advanced stages. Here, we developed a novel strategy to generate somatic ovarian cancer mouse models using a combination of in vivo electroporation and CRISPR/Cas9 mediated genome editing. We mutated tumor suppressor genes associated with HGSC in two different combinations; Brca1, Tp53, Pten with/without Lkb1 and successfully generated HGSC, however, with different latencies and pathophysiology. By utilizing Cre lineage tracing in our system, we visualized peritoneal micrometastases in an immune-competent environment. Because our strategy is flexible in selecting mutation combinations and targeting areas, it would be useful for generating ovarian cancer mouse models. Significance StatementHigh grade serous ovarian cancer (HGSC) is the most common ovarian malignancy but our knowledge of early tumorigenesis is still quite limited due to late diagnosis of patients. We developed a new strategy of generating mouse ovarian cancer models using a combination of in vivo electroporation and CRISPR-mediated genome editing. We demonstrated that a combination of three tumor suppressor gene mutations (Brca1, Tp53 and Pten) is sufficient to develop HGSCs. Interesting, an additional mutation in Lkb1 drastically changed tumor latency, penetrance and pathophysiology through changing its cell-of-origin. Our strategy is highly flexible in selection of mutation combinations and targeting areas in immune competent mice and useful to study early tumorigenesis of ovarian cancer.

cancer biology

Anatomical and cellular heterogeneity in the mouse oviduct-- its potential roles in reproduction and preimplantation development

The oviduct/fallopian tube is a tube-like structure that extends from the uterus to the ovary. It is an essential reproductive tissue that provides an environment for internal fertilization and preimplantation development. However, our knowledge of its regional and cellular heterogeneity is still limited. Here, we examined the anatomical complexity of mouse oviducts using modern imaging techniques and fluorescence reporter lines. We found that there are basic coiling patterns and turning points in the coiled mouse oviduct can serve as reliable landmarks for luminal morphological regionalities. We identified previously unrecognized anatomical structures in the isthmus and uterotubal junction (UTJ) that likely play important roles in reproduction. Interestingly, during ovulation, the isthmus was transiently plugged by a thick mucus, keeping the oocytes within the ampulla. Preimplantation embryos travelled along the oviduct and formed a queue within small compartments of the UTJ before uterine entry. Taken together, the oviduct luminal epithelium had highly diverse luminal structures with distinct cell populations reflecting its complex functions in reproduction.

physiology

Oviduct epithelial cells constitute two developmentally distinct lineages that are spatially separated along the distal-proximal axis

Owing to technical advances in single cell biology, the appreciation of cellular heterogeneity has increased, which has aided our understanding of organ function, homeostasis and disease progression. The oviduct (also known as the fallopian tube in humans) is the distal-most portion of the female reproductive tract. It is essential for reproduction and the proposed origin of high grade serous ovarian carcinoma (HGSOC). In mammals, the oviduct is morphologically segmented along the ovary-uterus axis into four evolutionally conserved regions. It is unknown however if there is a diversification of epithelial cell characteristics between these regions. In this study, we identified transcriptionally distinct populations of secretory and multiciliated cells restricted to the distal and proximal regions of the oviduct. We demonstrated that these distal and proximal populations are distinct lineages specified early in Mullerian duct development and are maintained separately. These results aid our understanding of epithelial development, homeostasis and initiation of disease from the oviduct.

developmental biology