RNA Sequencing of Carboplatin- and Paclitaxel-Resistant Endometrial Cancer Cells Reveals New Stratification Markers and Molecular Targets for Cancer Treatment.

Despite advances in surgical technique and adjuvant treatment, endometrial cancer has recently seen an increase in incidence and mortality in the USA. The majority of endometrial cancers can be cured by surgery alone or in combination with adjuvant chemo- or radiotherapy; however, a subset of patients experience recurrence for reasons that remain unclear. Recurrence is associated with chemoresistance to carboplatin and paclitaxel and consequentially, high mortality. Understanding the pathways involved in endometrial cancer chemoresistance is paramount for the identification of biomarkers and novel molecular targets for this disease. Here, we generated the first matched pairs of carboplatin-sensitive/carboplatin-resistant and paclitaxel-sensitive/paclitaxel-resistant endometrial cancer cells and subjected them to bulk RNA sequencing analysis. We found that 45 genes are commonly upregulated in carboplatin- and paclitaxel-resistant cells as compared to controls. Of these, the leukemia inhibitory factor, (LIF), the protein tyrosine phosphatase type IVA, member 3 (PTP4A3), and the transforming growth factor beta 1 (TGFB1) showed a highly significant correlation between expression level and endometrial cancer overall survival (OS) and can stratify the 545 endometrial cancer patients in the TCGA cohort into a high-risk and low-risk-cohorts. Additionally, four genes within the 45 upregulated chemoresistance-associated genes are ADAMTS5, MICAL2, STAT5A, and PTP4A3 codes for proteins for which small-molecule inhibitors already exist. We identified these proteins as molecular targets for chemoresistant endometrial cancer and showed that treatment with their correspondent inhibitors effectively killed otherwise chemoresistant cells. Collectively, these findings underline the utility of matched pair of chemosensitive and chemoresistant cancer cells to identify markers for endometrial cancer risk stratification and to serve as a pharmacogenomics model for identification of alternative chemotherapy approaches for treatment of patients with recurrent disease

A study of unusual metabolic variants of <italic>Aeromonas caviae</italic> and <italic>Aeromonas hydrophila</italic> using a polyphasic taxonomic approach

Variation in acid production from carbohydrate metabolism has been identified in Aeromonas as a potential indicator for new subspecies. Therefore, pure cultures of non-lactose fermenting Aeromonas caviae, a cause of waterborne infections in humans and other vertebrates, were studied after noting a mixture of acid producing and non-acid producing colonies after four days of incubation on MacConkey agar at ambient temperature. Unusual arabinose negative strains of A. hydrophila (usually arabinose positive) were added to the project to further study the correlation between carbohydrate fermentation and taxonomy. These metabolic variants of A. caviae and A. hydrophila were studied for phenotypic differences via carbohydrate utilization assays as well as genotypic differences via FAFLP. The results suggest that the A. caviae isolates MB3 and MB7 should be considered novel subspecies, while the arabinose negative strain designated A. hydrophila subsp. dhakensis is correctly identified as a subspecies of A. hydrophila

Targeting Mitochondria for Treatment of Chemoresistant Ovarian Cancer

Ovarian cancer is the leading cause of death from gynecologic malignancy in the Western world. This is due, in part, to the fact that despite standard treatment of surgery and platinum/paclitaxel most patients recur with ultimately chemoresistant disease. Ovarian cancer is a unique form of solid tumor that develops, metastasizes and recurs in the same space, the abdominal cavity, which becomes a unique microenvironment characterized by ascites, hypoxia and low glucose levels. It is under these conditions that cancer cells adapt and switch to mitochondrial respiration, which becomes crucial to their survival, and therefore an ideal metabolic target for chemoresistant ovarian cancer. Importantly, independent of microenvironmental factors, mitochondria spatial redistribution has been associated to both tumor metastasis and chemoresistance in ovarian cancer while specific sets of genetic mutations have been shown to cause aberrant dependence on mitochondrial pathways in the most aggressive ovarian cancer subtypes. In this review we summarize on targeting mitochondria for treatment of chemoresistant ovarian cancer and current state of understanding of the role of mitochondria respiration in ovarian cancer. We feel this is an important and timely topic given that ovarian cancer remains the deadliest of the gynecological diseases, and that the mitochondrial pathway has recently emerged as critical in sustaining solid tumor progression

Identification of Virulence Properties in <i>Salmonella</i> Typhimurium DT104 Using <i>Caenorhabditis elegans</i>

<div><p><i>Salmonella enterica</i> serover Typhimurium definitive phage type DT104, resistant to multiple antibiotics, is one of the most widespread <i>Salmonella</i> species in human infection worldwide. Although several cohort studies indicate that DT104 carrying the multidrug resistance (MDR) locus on salmonella genomic island 1 is a possible hyper-virulent strain compared to DT104 strains without MDR, or other <i>Salmonella enterica</i> serotypes, existing experimental evidence regarding virulence properties associated with the MDR region is controversial. To address this question, we constructed an isogenic MDR deletion (∆MDR) mutant strain of DT104, SNS12, by allelic exchange and used <i>Caenorhabditis elegans</i> as a host model to assess differences in virulence between these two strains. SNS12 exhibited decreased virulence in <i>C. elegans</i>, and we observed increased colonization and proliferation of the intestine of <i>C. elegans</i> by DT104. The immune response against MDR-carrying DT104 appears to function through a non-canonical Unfolded Protein Response (UPR) pathway, namely prion-like-(QN-rich)-domain-bearing protein pathway (PQN), in a <i>ced-1</i> dependent manner in <i>C. elegans</i>. Further, we also demonstrate that genes of the PQN pathway and antimicrobial peptide gene <i>abf-2</i>, are expressed at higher transcriptional levels in worms immediately following exposure to DT104, in comparison with worms exposed to SNS12. Altogether, our results suggest that the MDR region of <i>Salmonella</i> Typhimurium DT104 has a direct role in virulence against <i>Caenorhabditis elegans.</i></p> </div

Antimicrobial response to wild type <i>Salmonella</i> Typhimurium DT104.

<p>Expression of (A) <i>pqn-54</i>, (B) <i>abu-1</i>, (C) <i>abf-2</i> and (D) <i>abu-11</i> genes of <b>N2</b> worms as determined by qRT-PCR at one hour, 24-hour and 48-hour exposure. Relative expression levels (DT104 or SNS12 over OP 50) are shown as fold changes (mean ± std. err.).</p

<i>Ced-1</i> mutant <i>C. elegans</i> worms are more sensitive to killing by DT104.

<p><i>Ced-1</i> loss-of-function mutant worms [<i>ced-1</i>(e1735)] die significantly faster (P=0.0085) than wild type N2 worms, when exposed to <i>Salmonella</i> Typhimurium DT104. <b>L4</b> stage wild type <b>N2</b> (--●--) and <b><i>ced-1</i></b> (e1735) (--■--) worms were exposed to DT104 and assayed daily for survival.</p