Guadecitabine (SGI‐110) priming sensitizes hepatocellular carcinoma cells to oxaliplatin

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135710/1/mol22015991799.pd

Mpn-238 single-cell RNA profiling of myelofibrosis patients reveals pelabresib-induced decrease of megakaryocytic progenitors and normalization of CD4+ T cells in peripheral blood

Context: Abnormal differentiation of the megakaryocytic lineage and overproduction of proinflammatory cytokines, resulting in bone marrow fibrosis, anemia, symptoms, extramedullary hematopoiesis, and often hepatosplenomegaly, are key characteristics of myelofibrosis. Bromodomain and extraterminal domain (BET) proteins play a significant role in the regulation of neoplastic myeloproliferation and proinflammatory cytokine production. Pelabresib (CPI-0610) is an investigational, oral, small-molecule BET inhibitor. Objective: Characterize cellular composition and transcriptional alterations in peripheral blood (PB) obtained from myelofibrosis patients enrolled in three arms (Arm 1: pelabresib monotherapy; Arm 2: pelabresib ‘add-on’ to ruxolitinib in patients with suboptimal ruxolitinib response; Arm 3: pelabresib with ruxolitinib in JAKi-naïve patients) of the ongoing MANIFEST Phase 2 study (NCT02158858). Methods: We performed single-cell RNA sequencing on 234,904 CD34+ HSPCs and 135,970 CD34– mature PB cells. Baseline and on-treatment samples were obtained from a random pool of 20 patients (Arm 1: n=5; Arm 2: n=8; Arm 3: n=7). Mobilized PB cells from healthy donors (HD) were used as controls (n=11). Results: Analysis of CD34+ HSPCs at baseline demonstrated increased numbers of megakaryocytic, neutrophilic, and erythroid progenitors in myelofibrosis patients compared with HDs and a significant reduction of myeloid and B-cell lineage progenitors. Pelabresib as monotherapy and combined with ruxolitinib led to significant reduction of megakaryocytic, neutrophilic, and erythroid progenitors compared with baseline. Analysis of CD34– cells from myelofibrosis patients identified a significantly lower proportion of CD4+ T cells and increased numbers of erythroid cells at baseline versus HD. Individual patients exhibited reduction in natural killer cells and CD16+ monocytes as well as elevated megakaryocytic lineage cells. Pelabresib as monotherapy and combined with ruxolitinib increased the proportion of CD4+ T cells, and, importantly, reduced megakaryocytic lineage cells in both treatment-naïve and ruxolitinib-relapsed/refractory patients. In myelofibrosis patients at baseline, larger spleen volume was observed in patients with lower numbers of CD4+ T cells and increased numbers of megakaryocytic and myeloid CSF3R+ cells. Conclusions: Single-cell profiling of a subset of myelofibrosis patients in the MANIFEST study suggests that pelabresib alone and in combination with ruxolitinib induces improvement of the myeloid–lymphoid imbalance. This potential disease-modifying effect warrants further investigation

Epigenetic targeting of ovarian cancer stem cells

Emerging results indicate that cancer stem-like cells contribute to chemoresistance and poor clinical outcomes in many cancers, including ovarian cancer. As epigenetic regulators play a major role in the control of normal stem cell differentiation, epigenetics may offer a useful arena to develop strategies to target cancer stem-like cells. Epigenetic aberrations, especially DNA methylation, silence tumor-suppressor and differentiation-associated genes that regulate the survival of ovarian cancer stem-like cells (OCSC). In this study, we tested the hypothesis that DNA-hypomethylating agents may be able to reset OCSC toward a differentiated phenotype by evaluating the effects of the new DNA methytransferase inhibitor SGI-110 on OCSC phenotype, as defined by expression of the cancer stem-like marker aldehyde dehydrogenase (ALDH). We demonstrated that ALDH(+) ovarian cancer cells possess multiple stem cell characteristics, were highly chemoresistant, and were enriched in xenografts residual after platinum therapy. Low-dose SGI-110 reduced the stem-like properties of ALDH(+) cells, including their tumor-initiating capacity, resensitized these OCSCs to platinum, and induced reexpression of differentiation-associated genes. Maintenance treatment with SGI-110 after carboplatin inhibited OCSC growth, causing global tumor hypomethylation and decreased tumor progression. Our work offers preclinical evidence that epigenome-targeting strategies have the potential to delay tumor progression by reprogramming residual cancer stem-like cells. Furthermore, the results suggest that SGI-110 might be administered in combination with platinum to prevent the development of recurrent and chemoresistant ovarian cancer

The novel, small-molecule DNA methylation inhibitor SGI-110 as an ovarian cancer chemosensitizer

PURPOSE: To investigate SGI-110 as a "chemosensitizer" in ovarian cancer and to assess its effects on tumor suppressor genes (TSG) and chemoresponsiveness-associated genes silenced by DNA methylation in ovarian cancer. EXPERIMENTAL DESIGN: Several ovarian cancer cell lines were used for in vitro and in vivo platinum resensitization studies. Changes in DNA methylation and expression levels of TSG and other cancer-related genes in response to SGI-110 were measured by pyrosequencing and RT-PCR. RESULTS: We demonstrate in vitro that SGI-110 resensitized a range of platinum-resistant ovarian cancer cells to cisplatin (CDDP) and induced significant demethylation and reexpression of TSG, differentiation-associated genes, and putative drivers of ovarian cancer cisplatin resistance. In vivo, SGI-110 alone or in combination with CDDP was well tolerated and induced antitumor effects in ovarian cancer xenografts. Pyrosequencing analyses confirmed that SGI-110 caused both global (LINE1) and gene-specific hypomethylation in vivo, including TSGs (RASSF1A), proposed drivers of ovarian cancer cisplatin resistance (MLH1 and ZIC1), differentiation-associated genes (HOXA10 and HOXA11), and transcription factors (STAT5B). Furthermore, DNA damage induced by CDDP in ovarian cancer cells was increased by SGI-110, as measured by inductively coupled plasma-mass spectrometry analysis of DNA adduct formation and repair of cisplatin-induced DNA damage. CONCLUSIONS: These results strongly support further investigation of hypomethylating strategies in platinum-resistant ovarian cancer. Specifically, SGI-110 in combination with conventional and/or targeted therapeutics warrants further development in this setting

Refractory testicular germ cell tumors are highly sensitive to the second generation DNA methylation inhibitor guadecitabine

Testicular germ cell tumors (TGCTs) are the most common cancers of young males. A substantial portion of TGCT patients are refractory to cisplatin. There are no effective therapies for these patients, many of whom die from progressive disease. Embryonal carcinoma (EC) are the stem cells of TGCTs. In prior in vitro studies we found that EC cells were highly sensitive to the DNA methyltransferase inhibitor, 5-aza deoxycytidine (5-aza). Here, as an initial step in bringing demethylation therapy to the clinic for TGCT patients, we evaluated the effects of the clinically optimized, second generation demethylating agent guadecitabine (SGI-110) on EC cells in an animal model of cisplatin refractory testicular cancer. EC cells were exquisitely sensitive to guadecitabine and the hypersensitivity was dependent on high levels of DNA methyltransferase 3B. Guadecitabine mediated transcriptional reprogramming of EC cells included induction of p53 targets and repression of pluripotency genes. As a single agent, guadecitabine completely abolished progression and induced complete regression of cisplatin resistant EC xenografts even at doses well below those required to impact somatic solid tumors. Low dose guadecitabine also sensitized refractory EC cells to cisplatin in vivo. Genome-wide analysis indicated that in vivo antitumor activity was associated with activation of p53 and immune-related pathways and the antitumor effects of guadecitabine were dependent on p53, a gene rarely mutated in TGCTs. These preclinical findings suggest that guadecitabine alone or in combination with cisplatin is a promising strategy to treat refractory TGCT patients

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly