Hotspot SF3B1 mutations induce metabolic reprogramming and vulnerability to serine deprivation.

Cancer-associated mutations in the spliceosome gene SF3B1 create a neomorphic protein that produces aberrant mRNA splicing in hundreds of genes, but the ensuing biologic and therapeutic consequences of this missplicing are not well understood. Here we have provided evidence that aberrant splicing by mutant SF3B1 altered the transcriptome, proteome, and metabolome of human cells, leading to missplicing-associated downregulation of metabolic genes, decreased mitochondrial respiration, and suppression of the serine synthesis pathway. We also found that mutant SF3B1 induces vulnerability to deprivation of the nonessential amino acid serine, which was mediated by missplicing-associated downregulation of the serine synthesis pathway enzyme PHGDH. This vulnerability was manifest both in vitro and in vivo, as dietary restriction of serine and glycine in mice was able to inhibit the growth of SF3B1MUT xenografts. These findings describe a role for SF3B1 mutations in altered energy metabolism, and they offer a new therapeutic strategy against SF3B1MUT cancers

Correction: A novel epigenetic modulating agent sensitizes pancreatic cells to a chemotherapy agent.

[This corrects the article DOI: 10.1371/journal.pone.0199130.]

A novel epigenetic modulating agent sensitizes pancreatic cells to a chemotherapy agent.

Pancreatic ductal adenocarcinoma (PDAC) is expected to be the second leading cause of cancer mortality by 2030. PDAC remains resistant to the majority of systemic chemotherapies. In this paper, we explore if epigenetic sensitization can improve chemotherapy response in PDAC. Multiple PDAC cell lines were tested with serial concentrations of the epigenetic modulators 5-azacitidine (Aza) and guadecitabine (SGI-110). Guadecitabine was effective at inhibiting the expression of DNA Methyltransferase 1 (DNMT1) and in decreasing cell viability at nanomolar concentrations. We also report that guadecitabine has increased efficacy following a delay period or as we reference, a 'rest period'. Sensitization with guadecitabine improved response to the chemotherapeutic agent-Irinotecan- as measured by decreased cell viability and accompanied by an increase in caspase activity. Additional studies are needed to understand the mechanism of action

Variable response of pancreatic cell lines to epigenetic modulator <i>in vitro</i>.

<p>Cells were treated daily with an epigenetic modulator at different concentrations for up to 5 days (Fig 1A–1E). For guadecitabine, doses in nanomolar range are magnified to demonstrate the effectiveness of this modulator at low doses. At the end of the treatment, a standard MTT assay was used to determine cell viability. The percent viability was calculated by dividing each data point by its respective control and designated by percentages. Data shown represents mean ± SEM.</p

Challenges and Strategies of Successful Mentoring: The Perspective of LEADS Scholars and Mentors from Minority Serving Institutions

Mentoring continues to be a salient conversation in academia among junior and senior faculty and administrators. Mentors provide guidance and structure to junior faculty so that they can meet their academic and professional goals. Mentors also convey skills in balancing life and academic pursuits. Therefore, the purpose of this descriptive study was to provide additional insight from a training program called Leading Emerging and Diverse Scientists to Success (LEADS) regarding successful strategies and challenges of mentoring relating to lessons learned from the scholars and mentees’ perspective. The LEADS program provided multiple training platforms to increase skills and knowledge regarding research to promote expertise in grant writing and submission for funding opportunities among diverse scientists. These findings reinforce the knowledge about the value of a mentor in helping define the research pathway of their mentee and underscoring the importance of mentoring

Negligible cytotoxicity in pancreatic cells due to guadecitabine.

<p>Miapaca-2 (a) and Panc1 (b) cells were treated with 0.14x10^-3 μM of guadecitabine for 3 days and immediately treated with Irinotecan for 5 days, or allowed to rest for 5 days and then treated with Irinotecan. LDH was measured using the cytotoxicity kit mentioned previously. The data were analyzed according to manufacturer’s instructions. Analysis was done using a non-parametric t test. Data shown represents mean ± SEM.</p

Effect of guadecitabine on DNA Methyltransferase 1, and its delayed response.

<p>Miapaca-2 and Panc1 were treated with guadecitabine (0–8 μM) for three days. The two cell lines were fixed and further stained with Propidium Iodide and analyzed using flow cytometry methods to evaluate cell cycle arrest. The pink color represents G0G1 phase, dark blue -S phase, and light blue -G2_M phase, respectively. The data was analyzed using DIVA software (a). Pancreatic cells were treated with guadecitabine at 0.14x10^-3 μM (b-f) for 3 days. Levels of DNMT1 expression were measured via Western blotting following treatment (b). To quantify apoptotic activity, Caspase 3/7 levels were measured after 0, 5, or 10 days of rest. Each experimental value was compared with control and plotted in terms of percentages using Graph Pad Prism (c).The amount of necrosis was calculated using a LDH detection kit following treatment with no rest or rest (d). Images were taken for treated and untreated cells for Miapaca-2 and Panc1 at 10X magnification using EVOS cell imaging system (e-f).Statistical analysis was performed using a one-way ANOVA and significance measured with a Tukey’s multiple comparison test (c) or utilizing a non-parametric t test (d). Data represented shows mean ± SEM (2c-2d).</p

Guadecitabine sensitized PDAC cells to chemotherapy.

<p>Miapaca-2 (a) and Panc1 (b) were treated with 0.14x10^-3 μM for 3 days. Cells were treated with varying concentrations of Irinotecan either immediately or after 5 days of rest. Cells were incubated in Irinotecan for an additional 5 days. Viability was measured using a standard MTT assay. Each data point was compared to the control respectively, and represented as percent cell viability. Statistical analysis was performed using a non-parametric t test. Data shown represents mean ± SEM.</p

Pre-sensitized cells by guadecitabine upregulated apoptosis.

<p>Miapaca-2 (a) and Panc1 (b) cells were pretreated with 0.14x10^-3 μM of guadecitabine for 3 days. The cells were either treated immediately or given rest for 5 days. Afterwards, the cells were treated with different concentrations of Irinotecan for 5 days. Caspase activity was measured and statistical analyses was done as mentioned earlier. A non-parametric t test was used for statistical analysis. Data shown represents mean ± SEM.</p