Sensitivity of HER2-amplified colorectal organotypic cancer spheroids at ex vivo resistance to panitumumab and trastuzumab

68

Background: HER2 amplification is an emerging biomarker in colorectal cancer (CRC) with increased copy number associated with improved clinical outcomes to HER2 targeting. RAS/RAF wildtype CRC also benefit from use of epidermal growth factor receptor inhibition (EGFRi). The sequencing of EGFRi versus HER2 inhibition in low copy number HER2 amplified CRC remains uncertain. Patient-derived cancer organoids (PDCOs) allow an ex vivo method to assess treatment sensitivity. We examined treatment sensitivity of a HER2 amplified PDCO at baseline and following resistance to panitumumab and trastuzumab. Methods: Following IRB-approval, fresh CRC tissue was cultured to maturation. After expansion, subcultures were treated with stepwise (20%) increase to physiologic Cmax of panitumumab (230ug/mL) and trastuzumab (180ug/mL). Threshold for escalation was median relative growth of +20% at 96h. Sensitivity was assessed on primary culture (RC1), panitumumab resistance (RC1-P) and trastuzumab resistance (RC1-T) using 96h of physiologic Cmax panitumumab, trastuzumab, and combination trastuzumab/pertuzumab. Individual sphere response was assessed for change in mean NADH autofluorescence intensity and ratio of NADH/FAD signal. Response was assessed at 96h in comparison to control using effect size of Glass’s Delta (GΔ). Results: Molecular profiling revealed HER2 copy number of 14 with no concurrent alterations in RAS, RAF, or PIK3CA. Time to resistance was similar between panitumumab (55 days) and trastuzumab (51 days). RC1 had baseline growth (+116%) which was reduced with single agent panitumumab (+17%, GΔ=1.40) with intermediate sensitivity to trastuzumab (+48%, GΔ=0.95) and trastuzumab/pertuzumab (46%, GΔ=0.99). Normalized NADH/FAD ratio revealed significant metabolic response to panitumumab (-20%, GΔ=0.66) and trastuzumab/pertuzumab (-35%, GΔ=1.16) with insignificant effect of single agent trastuzumab (-14%, GΔ=0.46). Following resistance to panitumumab, RC1-P had persistent growth with trastuzumab (+68%) which improved in combination trastuzumab/pertuzumab (+34%, GΔ=1.16). Following resistance to trastuzumab, RC1-T was insensitive to EGFRi with panitumumab including persistent growth (+58%, GΔ=0.70) and unchanged metabolism (+2%, GΔ=-0.10). Conclusions: Therapeutic dose escalation in a single PDCO of HER2 amplified CRC suggests improved sensitivity to EGFRi and dual HER2 targeting with trastuzumab/pertuzumab. Resistance to EGFRi resulted in persistent sensitivity to dual HER2 inhibition using trastuzumab/pertuzumab, however resistance to single agent trastuzumab. Resistance to trastuzumab resulted in future insensitivity to EGFRi. Molecular profiling at resistance revealed no pathologic alterations in EGFR or ERBB2 signaling, with ongoing analysis of transcriptional changes by RNAseq.

Abstract 1494: Etiologies of patient-derived colorectal cancer organoid growth heterogeneity across multiple patient samples and culture conditions

Background: Patient-derived cancer organoids (PDCOs) are emerging as an in vitro model to recapitulate the molecular and phenotypic features of colorectal cancer (CRC). Heterogeneity in established CRC PDCOs has been observed in the underlying molecular profiles and growth characteristics at the individual organoid level. Here, we present a dedicated assessment of individual organoid growth as a function of experimental culture parameters.

Methods: CRC PDCO cultures were established from patient biopsy/resection specimens following patient consent to an IRB-approved protocol. Growth was assessed by relative change in diameter at 48h. Baseline size was compared to relative growth at 48h using coefficient of determination (R). Interquartile sets were compared by effect size of Glass's Delta (GΔ) to compare change difference in average growth normalized to standard deviation and defined with significance 1.0. Impact of density was assessed by manual count of spheroids and lines plated across varied densities and compared to 48h relative growth. Growth rates were compared as both absolute and relative passage number.

Results: 22 unique cultures were established from fresh tissue and representative of CRC including pathologic alterations in APC, KRAS, NRAS, BRAF, PIK3CA TP53, MTOR and PTEN. Pairwise spheres were assessed at baseline and 48h for analysis (n=1714) with mean relative growth rate of 27.1% (range -40.0, 156.2%). Baseline size did not predict relative growth at 48h (R=0.023) with insignificant interquartile effect size [0.10, 0.07, 0.32]. Replicates (n=63) across a range of passages [1, 36] including line-specific relative passage number [0-14] did not predict change in relative growth (R<0.001) with insignificant interquartile effect size [-0.02, 0.15, 0.19]. Fields of view (n=135) were assessed for absolute sphere number [1, 72]. Increased sphere density across cultures also did not predict change in relative growth (R=0.002) with insignificant interquartile effect size [-0.29, -0.32, -0.29]. Two individual cultures were assessed for the impact of density on respective growth without significance at relative plating ratios of 1:5 (GΔ=-0.52, 0.42), 1:10 (GΔ=-0.63, 0.07), and 1:50 (GΔ=-0.40, 0.12).

Conclusions: Following culture maturation, CRC PDCOs have heterogeneous growth rates at the organoid level. These studies demonstrate that the growth rate is independent of baseline organoid size, passage number, or culture plating density. Understanding the effect of culture variation helps to define meaningful population effects in response and resistance to therapy and supports the translation of this technology as a future predictive biomarker.

Citation Format: Aishwarya Sunil, Jeremy D. Kratz, Sarbjeet K. Makkar, Suhjah Rehman, Amani A. Gillette, Katherine A. Johnson, Cheri A. Pasch, Linda Clipson, Kristina A. Matkowskyj, Melissa C. Skala, Dustin A. Deming. Etiologies of patient-derived colorectal cancer organoid growth heterogeneity across multiple patient samples and culture conditions [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1494.

Protein profiles of hatchery egg shell membrane

Background

Eggshells which consist largely of calcareous outer shell and shell membranes, constitute a significant part of poultry hatchery waste. The shell membranes (ESM) not only contain proteins that originate from egg whites but also from the developing embryos and different contaminants of microbial and environmental origins. As feed supplements, during post hatch growth, the hatchery egg shell membranes (HESM) have shown potential for imparting resistance of chickens to endotoxin stress and exert positive health effects. Considering that these effects are mediated by the bioactive proteins and peptides present in the membrane, the objective of the study was to identify the protein profiles of hatchery eggshell membranes (HESM).

Methods

Hatchery egg shell membranes were extracted with acidified methanol and a guanidine hydrochloride buffer then subjected to reduction/alkylation, and trypsin digestion. The methanol extract was additionally analyzed by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS). The tryptic digests were analyzed by liquid chromatography and tandem mass spectrometry (LC-MS-MS) to identify the proteins.

Results

Our results showed the presence of several proteins that are inherent and abundant in egg white such as, ovalbumin, ovotransferrin, ovocleidin-116, and lysozyme, and several proteins associated with cytoskeletal, cell signaling, antimicrobial, and catalytic functions involving carbohydrate, nucleic acid, and protein metabolisms. There were some blood derived proteins most likely originating from the embryos and several other proteins identified with different aerobic, anaerobic, gram positive, gram negative, soil, and marine bacterial species some commensals and others zoonotic.

Conclusion

The variety of bioactive proteins, particularly the cell signaling and enzymatic proteins along with the diverse microbial proteins, make the HESM suitable for nutritional and biological application to improve post hatch immunity of poultry.

Electronic supplementary material

The online version of this article (doi:10.1186/s12953-017-0112-6) contains supplementary material, which is available to authorized users.

Comparative proteomic analysis of chicken macrophages stimulated with Salmonella Lipopolysaccharide (LPS) and Monosodium Urate (MSU) Crystals

Immune system cells are armed with recognition receptors by means of which they can sense pathogen associated molecular patterns (PAMPs) and damage associated molecular patterns (DAMPs). Interaction of pathogen as well as damage associated ligands with their cognate receptors drives transcriptional and translational changes. To study the proteomic differences between signal transduction pathways involved in microbial induced and sterile injury, we used chicken macrophages HTC as a model system. Cells were labeled and treated with LPS or MSU by using SILAC proteomic approach. After 20 hrs of stimulation, the protein was extracted from secretome and cell lysate, quantified and subjected to in-solution digestion followed by liquid chromatography/tandem mass spectrometry. We quantified 150 proteins using Skyline software, 30 were upregulated and 18 down regulated in LPS treated cells and 40 upregulated and 11 down regulated in MSU treated cells. Interleukin 8, a secretory protein is differentially upregulated in LPS group. Cathepsin K, vimentin, kinases are some of the significantly upregulated cell lysate proteins in LPS group. Lactate dehydrogenase, heat shock, microtubule, annexin are significantly upregulated in MSU stimulated cell lysate. Functional annotation of proteins in both the groups by gene ontology software shows most of the proteins are involved in cytoskeleton remodeling, cell migration and cell signaling, which may be important in immune activation except nucleic acid binding transcription activity factor proteins which are uniquely expressed in LPS group. In conclusion our study gives an insight about the functional differences between pathogen and sterile associated inflammation at cellular level.

Proteomic Changes in Chicken Plasma Induced by Salmonella typhimurium Lipopolysaccharides

Lipopolysaccharides (LPS) are cell wall components of Gram-negative bacteria that produce inflammation and sickness in higher animals. The objective was to identify plasma proteomic changes in an avian model of inflammation. Chickens were treated with either saline or LPS, and blood was collected at 24 hours postinjection. The pooled plasma samples were depleted of high-abundant proteins and analyzed by matrix-assisted laser desorption ionization (MALDI)-time-of-flight mass spectrometry and liquid chromatography–tandem mass spectrometry (LC–MS/MS). MALDI analyses showed an increase in fibrinogen beta-derived peptide and a decrease in apolipoprotein-AII-derived peptide in LPS samples. Label-free quantitation of LC–MS/MS spectra revealed an increase in the levels of α1-acid glycoprotein, a chemokine CCLI10, and cathelicidin-2, but a decrease in an interferon-stimulated gene-12-2 protein in the LPS group. These differentially expressed proteins are associated with immunomodulation, cytokine changes, and defense mechanisms, which may be useful as candidate biomarkers of infection and inflammation.

Effect of butyrate on immune response of a chicken macrophage cell line

Butyric acid is a major short chain fatty acid (SCFA), produced in the gastrointestinal tract by anaerobic bacterial fermentation, that has beneficial health effects in many species including poultry. To understand the immunomodulating effects of butyrate on avian macrophage, we treated a naturally transformed line of chicken macrophage cells named HTC with Na-butyrate in the absence or presence of Salmonella typhimurium lipopolysaccharide (LPS) or phorbol-12-myristate-13-acetate (PMA), a metabolic activator, evaluating its various functional parameters. The results demonstrate that, butyrate by itself had no significant effect on variables such as nitric oxide (NO) production and the expression of genes associated with various inflammatory cytokines but it inhibited NO production, and reduced the expression of cytokines such as IL-1β, IL-6, IFN-γ, and IL-10 in LPS-stimulated cells. Butyrate decreased the expression of TGF-β3 in the presence or absence of LPS, while it had no effect on IL-4, Tβ4, and MMP2 gene expression. In addition, butyrate augmented PMA induced oxidative burst indicated by DCF-DA oxidation and restored LPS induced attenuation of tartrate resistant acid phosphatase (TRAP) activity. Although butyrate had no significant effect on phagocytosis or matrix metalloproteinase (MMP) activities of resting macrophages, it significantly suppressed the effects induced by their respective stimulants such as LPS induced phagocytosis and PMA induced MMP expression. These results suggest that butyrate has immunomodulatory property in the presence of agents that incite the cells thus, has potential to control inflammation and restore immune homeostasis.