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 .

No abstract

The Colorado potato beetle (Leptinotarsa decemlineata (Say)) is an important pest of the cultivated potato (Solanum tuberosum (L.) [Solanales: Solanaceae]). With its broad resistance toward commonly used insecticides, it is clear that more sophisticated control strategies are needed. Due to their importance in insect development, microRNAs (miRNAs) represent a potential tool to employ in insect control strategies. However, most studies conducted in this area have focused on model species with well-annotated genomes. In this study, next-generation sequencing was used to catalogue the miRNAs produced by L. decemlineata across all eight stages of its development, from eggs to adults. For most stages, the length of miRNAs peaked between 21 and 22 nt, though it was considerably longer for the egg stage (26 nt). Global profiling of miRNAs revealed three distinct developmental clusters: 1) egg stage; 2) early stage (first, second, and third instar); and 3) late stage (fourth instar, prepupae, pupae, and adult). We identified 86 conserved miRNAs and 33 bonafide novel miRNAs, including stage-specific miRNAs and those not previously identified in L. decemlineata. Most of the conserved miRNAs were found in multiple developmental stages, whereas the novel miRNAs were often stage specific with the bulk identified in the egg stage. The identified miRNAs have a myriad of putative functions, including growth, reproduction, and insecticide resistance. We discuss the putative roles of some of the most notable miRNAs in the regulation of L. decemlineata development, as well as the potential applications of this research in Colorado potato beetle management.

In oviparous animals, the egg contains all resources required for embryonic development. The chorioallantoic membrane (CAM) is a placenta-like structure produced by the embryo for acid-base balance, respiration, and calcium solubilization from the eggshell for bone mineralization. The CAM is a valuable in vivo model in cancer research for development of drug delivery systems and has been used to study tissue grafts, tumor metastasis, toxicology, angiogenesis, and assessment of bacterial invasion. However, the protein constituents involved in different CAM functions are poorly understood. Therefore, we have characterized the CAM proteome at two stages of development (ED12 and ED19) and assessed the contribution of the embryonic blood serum (EBS) proteome to identify CAM-unique proteins. LC/MS/MS-based proteomics allowed the identification of 1470, 1445, and 791 proteins in CAM (ED12), CAM (ED19), and EBS, respectively. In total, 1796 unique proteins were identified. Of these, 175 (ED12), 177 (ED19), and 105 (EBS) were specific to these stages/compartments. This study attributed specific CAM protein constituents to functions such as calcium ion transport, gas exchange, vasculature development, and chemical protection against invading pathogens. Defining the complex nature of the CAM proteome provides a crucial basis to expand its biomedical applications for pharmaceutical and cancer research.

Background The presence of residual tumour at surgery (non-pathological complete response or non-pCR) occurs in about half of TNBCs treated with neoadjuvant chemotherapy (NAC) and signals chemoresistance and poor prognosis. Although further adjuvant chemotherapy (Capecitabine/Xeloda) results in improved survival in patients with non-pCR, only about 15% of such patients do benefit. Circulating tumor DNA (ctDNA) is a plasma-based biomarker that can be used to reveal real-time data about the disease and treatment progression. We have previously shown that detection of ctDNA after NAC signals poor prognosis. To validate and extend our previous results using an academic hospital-based tumor bespoke assay, we performed ctDNA measurements in non-pCR TNBC patients at the pre-operative, post-operative, 3 and 6-month time points. Methods Whole exome sequencing (WES) was performed on residual tumors from 34 TNBC patients to identify tumour-specific mutations (5/patient). Digital droplet PCR (ddPCR) assays were developed for these mutations and performed as per our previous work. Patients with at least one detectable mutation were considered ctDNA positive for a given time point. The detection of ctDNA was correlated with relapse-free survival (RFS). Results The overall RFS was 44%, with 56 % of patients received adjuvant Xeloda. Detection of ctDNA at the end of NAC (T1) correlated with poor prognosis of RFS (n = 33, p-value = 0.009, HR = 0.29 (95% CI = 0.12 to 0.74)). Detection of ctDNA after surgery (T2) and while on Xeloda (T3) showed no significant prognostic value for RFS. However, ctDNA detection at the 6-month time point, after Xeloda treatment (T4), showed stronger prognostic value for RFS (n = 17, p-value = 0.004, HR = 0.12 (95% CI = 0.03 to 0.51)). When measuring changes in ctDNA detectability from T1 to T4, 4 patients initially positive became ctDNA negative after the 6-month interval, and only 1 of these 4 had a relapse, compared with 10 of 11 that remained positive at the 6-month time point (p = 0.01, Chi-squared test). 3 of the 4 patients that cleared their ctDNA had received Xeloda. In addition, 2 patients initially negative became ctDNA positive at the 6-month time point (T4) and both relapsed, compared with only 1 of 5 that remained negative at 6 months (p = 0.035, Chi-squared test). For patients who received adjuvant Xeloda ctDNA positivity at T1 was associated with a worse RFS (p-value = 0.028, HR = 3.3884 (95% CI = 1.160 to 13.00)). Conclusion ctDNA testing using ddPCR in an academic hospital-based context at the post-NAC time point as well as at 6 months after surgery identifies an excellent prognostic group in TNBC patients with non-pCR and changes in ctDNA during the adjuvant period have prognostic value. This personalized approach to treatment management is ready for prospective testing in patients who have undergone NAC and require additional chemotherapy. Citation Format: Talia Roseshter, Anna Klemantovich, Luca Cavallone, Adriana Aguilar-Mahecha, Josiane Lafleur, Oluwadara O. Elebute, Sarah Jenna, Jean-Francois Boileau, Manuela Pelmus, Mark Basik, Cathy Lan. The prognostic role of circulating tumor DNA after neoadjuvant chemotherapy in triple negative breast cancer with residual tumor [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-11-26.

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.

No abstract