Project description:Treatment of PC3 and MDA-MB-231 cell lines with sublethal doses of docetaxel or cisplatin in vitro resulted in induction of polyploid cancer cells. Single cell copy RNA-sequencing was conducted to understand resistance of polyploid cancer cells to chemotherapy.
Project description:Treatment of PC3 and MDA-MB-231 cell lines with sublethal doses of docetaxel or cisplatin in vitro resulted in induction of polyploid cancer cells. Single cell copy number profiling was conducted to understand resistance of polyploid cancer cells to chemotherapy.
Project description:Considerable evidence suggests that breast cancer therapeutic resistance and relapse can be driven by polyploid giant cancer cells (PGCCs). The number of PGCCs increases with the stages of disease and therapeutic stress. Given the importance of PGCCs, it remains challenging to eradicate them. To discover effective anti-PGCC compounds, there is an unmet need to rapidly distinguish compounds that kill non-PGCCs, PGCCs, or both. Here, we establish a single-cell morphological analysis pipeline with a high throughput and great precision to characterize dynamics of individual cells. In this manner, we screen a library to identify promising compounds that inhibit all cancer cells or only PGCCs (e.g., regulators of HDAC, proteasome, and ferroptosis). Additionally, we perform scRNA-Seq to reveal altered cell cycle, metabolism, and ferroptosis sensitivity in breast PGCCs. The combination of single-cell morphological and molecular investigation reveals promising anti-PGCC strategies for breast cancer treatment and other malignancies.
Project description:To elucidate the mechanisms underlying relapse from chemotherapy in multiple myeloma we performed a longitudinal study of 33 patients entered into Total Therapy protocols investigating them using gene expression profiling, high resolution copy number arrays and whole exome sequencing. The study illustrates the mechanistic importance of acquired mutations in known myeloma driver genes and the critical nature of bi-allelic inactivation events affecting tumor suppressor genes, especially TP53. The end result being resistance to apoptosis and increased proliferation rates, which drive relapse by Darwinian type clonal evolution. The number of copy number aberration changes and bi-allelic inactivation of tumor suppressor genes was increased in GEP70 high risk, consistent with genomic instability being a key feature of high risk. In conclusion, the study highlights the impact of acquired genetic events, which enhance the evolutionary fitness level of myeloma propagating cells to survive multi-agent chemotherapy and to result in relapse.
Project description:Mortality from breast cancer is almost exclusively a result of tumor metastasis and resistance to therapy and therefore understanding the underlying mechanisms is an urgent challenge. Chemotherapy, routinely used to treat breast cancer, induces extensive tissue damage, eliciting an inflammatory response that may hinder efficacy and promote metastatic relapse. Here we show that systemic treatment with doxorubicin, but not cisplatin, following resection of a triple-negative breast tumor induced the expression of complement factors in lung fibroblasts and modulated an immunosuppressive metastatic niche that supported lung metastasis. CAF-derived complement signaling mediated the recruitment of myeloid-derived suppressor cells (MDSCs) to the metastatic niche, thus promoting T cell dysfunction. Pharmacological targeting of complement signaling in combination with chemotherapy alleviated immune dysregulation and attenuated lung metastasis. Our findings suggest that combining cytotoxic treatment with blockade of complement signaling in triple-negative breast cancer patients may attenuate the adverse effects of chemotherapy, thus offering a promising approach for clinical use.
Project description:Mortality from breast cancer is almost exclusively a result of tumor metastasis and resistance to therapy and therefore understanding the underlying mechanisms is an urgent challenge. Chemotherapy, routinely used to treat breast cancer, induces extensive tissue damage, eliciting an inflammatory response that may hinder efficacy and promote metastatic relapse. Here we show that systemic treatment with chemotherapy following resection of a triple-negative breast tumor induced the expression of complement factors in lung fibroblasts and modulated an immunosuppressive metastatic niche that supported lung metastasis. CAF-derived complement signaling mediated the recruitment of myeloid-derived suppressor cells (MDSCs) to the metastatic niche, thus promoting T cell dysfunction. Functionally, we show that pharmacological targeting of complement signaling in combination with chemotherapy alleviated immune dysregulation and attenuated lung metastasis. Our findings suggest that combining cytotoxic treatment with blockade of complement signaling in triple-negative breast cancer patients may attenuate the adverse effects of chemotherapy, thus offering a promising approach for clinical use.
Project description:In acute myeloid leukemias (AML), chemotherapy is frequently followed by disease relapse, yet the mechanism by which AML reemerges is not fully understood. We hypothesized that chemotherapy induces senescence-like dormancy that facilitates survival to genotoxic exposure, allowing AML cells to endure treatment in a transiently dormant state while retaining potential for leukemic repopulation. Here, we show that primary AML cells exhibit hallmark senescence features following treatment with cytarabine (AraC), including growth arrest, increased cellular granularity, senescence-associated-β-galactosidase (SA-β-gal) activity, and senescence-associated transcriptomic alterations. Induction of AraC-induced premature senescence was regulated by the ATR kinase activity and mediated stress-survival. High-throughput single cell RNA (scRNA)-seq analysis of primary AML cells ex vivo and in vivo following chemotherapy suggest active transcriptional programming towards senescent-like dormancy instead of enrichment for leukemia stem cells (LSCs). scRNA-seq of sorted AraC-induced premature senescent AML cells demonstrated a heterogenous population including a fraction of cells with simultaneous expression of dormancy- and senescence-associated gene signatures. Xenotransplantation of AraC-induced premature senescent AML cells into mice demonstrated that senescent-like AML cells maintain leukemia-repopulating potential. Altogether, we propose a mechanism of AML relapse whereby AML cells tolerate chemotherapy via acquisition of a transient senescent-like state.
Project description:In acute myeloid leukemias (AML), chemotherapy is frequently followed by disease relapse, yet the mechanism by which AML reemerges is not fully understood. We hypothesized that chemotherapy induces senescence-like dormancy that facilitates survival to genotoxic exposure, allowing AML cells to endure treatment in a transiently dormant state while retaining potential for leukemic repopulation. Here, we show that primary AML cells exhibit hallmark senescence features following treatment with cytarabine (AraC), including growth arrest, increased cellular granularity, senescence-associated-β-galactosidase (SA-β-gal) activity, and senescence-associated transcriptomic alterations. Induction of AraC-induced premature senescence was regulated by the ATR kinase activity and mediated stress-survival. High-throughput single cell RNA (scRNA)-seq analysis of primary AML cells ex vivo and in vivo following chemotherapy suggest active transcriptional programming towards senescent-like dormancy instead of enrichment for leukemia stem cells (LSCs). scRNA-seq of sorted AraC-induced premature senescent AML cells demonstrated a heterogenous population including a fraction of cells with simultaneous expression of dormancy- and senescence-associated gene signatures. Xenotransplantation of AraC-induced premature senescent AML cells into mice demonstrated that senescent-like AML cells maintain leukemia-repopulating potential. Altogether, we propose a mechanism of AML relapse whereby AML cells tolerate chemotherapy via acquisition of a transient senescent-like state.