Abstract 4011: Prognostic value of transcriptomic analysis in residual post neo-adjuvant triple negative breast cancer tumors

Background: Triple negative breast cancer is the most aggressive type of breast cancer. Approximately 50% of TNBC patients respond to pre-operative neo-adjuvant chemotherapy (NAC), however those patients with residual disease (non-pathological complete response or non-pCR) have a very poor prognosis. Recently, the use of capecitabine in the adjuvant setting was shown to increase disease-free survival in non-pCR patients. However, there are no biomarkers to identify patients who may benefit from adjuvant capecitabine. Moreover, novel therapeutic targets are needed to treat patients with non-pCR.

Methods: RNA extracted from 32 Formalin Fixed Paraffin Embedded (FFPE) residual post-NAC tumor samples underwent NanoString nCounter gene expression analysis using the BC360 panel as well as RNAseq.

Results: Comparison of tumors from poor (RFS<2 yrs) and good prognosis (RFS>2 yrs) patients showed 65 genes differentially expressed (≥1.5 fold change and p<0.05) by nCounter. 40 of these genes had differential expression also validated by RNAseq (R2= 0.96) and were selected for further pathway analysis. Gene Set Enrichment Analysis (GSEA) showed an enrichment for biological pathways involved in cell cycle, with all genes in this set upregulated in the poor prognosis group. GSEA analysis of 310 upregulated genes identified by RNAseq showed an enrichment for biological pathways associated with cell population proliferation and skin development. Interestingly, one of the upregulated genes identified was TYMS, encoding thymidylate synthase, the target of capecitabine, which showed 2-fold increased expression in the poor prognosis group (p≤0.005).

Conclusion: Our results suggest that residual tumors from TNBC patients who relapse within two years of surgery show transcriptomic evidence of increased proliferation and that expression levels of TYMS may be a potential biomarker to select patients for capecitabine in the adjuvant setting.

Citation Format: Adriana Aguilar-Mahecha, Yasamin Majedi, Oluwadara Elebute, Josiane Lafleur, Andreas Papadakis, Cathy Lan, Manuela Pelmus, Touhidur Rashid, Sarah Jenna, Mark Basik. Prognostic value of transcriptomic analysis in residual post neo-adjuvant triple negative breast cancer tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4011.

Role of the intestinal microbiome in low-density polyethylene degradation by caterpillar larvae of the greater wax moth, Galleria mellonella

Recently, a few insects, including the caterpillar larva of the greater wax moth Galleria mellonella, have been identified as avid 'plastivores'. These caterpillars are able to ingest and metabolize polyethylene at unprecedented rates. While it appears that G. mellonella plays an important role in the biodegradation process, the contribution of its intestinal microbiome remains poorly understood and contested. In a series of experiments, we present strong evidence of an intricate relationship between an intact microbiome, low-density polyethylene (LDPE) biodegradation and the production of glycol as a metabolic by-product. First, we biochemically confirmed that G. mellonella larvae consume and metabolize LDPE, as individual caterpillars fed on polyethylene excreted glycol, but those excretions were reduced by antibiotic treatment. Further, while the gut bacterial communities remained relatively stable regardless of diet, we showed that during the early phases of feeding on LDPE (24-72 h), caterpillars exhibited increased microbial abundance relative to those starved or fed on their natural honeycomb diet. Finally, by isolating and growing gut bacteria with polyethylene as their exclusive carbon source for over 1 year, we identified microorganisms in the genus Acinetobacter that appeared to be involved in this biodegradation process. Taken collectively, our study indicates that during short-term exposure, the intestinal microbiome of G. mellonella is intricately associated with polyethylene biodegradation in vivo.

The effects of calcium ions on the depression of cardiac contractility by chloroquine and quinine

The effects of chloroquine or quinine, 0.04 mg. ml-1 on the ventricular function curve of turtles were determined. Both drugs caused a shift of the curve to the right indicating a reduction in cardiac contractility. This depression of the curve was fully reversed on raising the external calcium concentration from 1.1 mmol.1-1 to 5.8 mmol.1-1 in the case of chloroquine and to 6.7 mmol.1-1 when quinine was used. The observations indicate that calcium ions are able to reverse the cardiodepression induced by chloroquine and quinine.

The renal escape from the sodium retaining effect of mineralocorticoids in spontaneously hypertensive rats

The effects of mineralocorticoids on urine and electrolyte excretion were studied in spontaneously hypertensive (SH) rats of Okamoto-Aoki strain and in normotensive white albino wistar strain rats. Sodium excretion fell from 0.568 meq/day to 0.336 meq/day a reduction of 40%, on the 4th day of steroid administration in the SH rats whilst a 30% reduction was observed on the 6th day in normotensive rats whilst urine volumes were not significantly altered in both groups. Similarly, the phase of acute sodium retention was reversed (renal escape) earlier in the SH rats on the 7th experimental day when further administration of mineralocorticoids resulted in a two-fold increased in sodium excretion. Urine volumes were significantly increased during this phase. The pattern of response in SH rats differ significantly in time and magnitude from the normotensive controls. As the renal escape phenomenon is linked with extracellular volume regulation these results highlight the exaggerated sensitivity to increases in blood volume associated with genetic spontaneous hypertension.

Intraperitoneal fluid infusion in children with gastroenteritis

In a study of 91 babies with dehydration as a result of gastroenteritis the intraperitoneal route was found to be safe and effective in those with mild or moderate dehydration, but not in those who were severely dehydrated. The fluids found to be most effective in the intraperitoneal technique were normal saline with 28 mEq of potassium chloride per litre, or for hypertonically dehydrated babies half-strength Darrow's solution. This technique can be carried out by a nurse working single-handed if the baby is premedicated with promazine.