Non-transformed Tissues Research Articles

Understanding the Preclinical Efficacy of Antibody-Drug Conjugates.

Antibody-drug conjugates (ADCs) represent a therapeutic modality that guides chemotherapies to tumoral cells by using antibodies against tumor-associated antigens (TAAs). The antibody and the chemotherapy or payload are attached by a chemical structure called the linker. The strategy for the development of this type of drug was based on several rational pillars, including the use of a very potent payload and the use of specific antibodies acting only on antigens expressed on tumoral cells. In this article, by using data from all approved ADCs that have received regulatory approval, we analyze the potential contribution of each ADC component to preclinical activity. We suggest that payload potency and the drug-to-antibody ratio (DAR) have a less relevant role in relation to efficacy than previously considered. Additionally, we have observed that some ADCs have been developed against antigens also present in non-transformed tissues, which could suggest that TAA specificity is not a mandatory requirement. Finally, we have identified that ADCs with payloads harboring more favorable physicochemical characteristics showed better potential activity. In this article, we also review other aspects that should be taken into consideration for ADC design, including linker structure, stability, conjugation type, pharmacokinetics, receptor internalization, and recycling. Based on currently available data, our study summaries different concepts that should be considered in the design of novel ADCs in the future.

Metabolomic Analysis of Histological Composition Variability of High-Grade Serous Ovarian Cancer Using 1H HR MAS NMR Spectroscopy.

In this work, the HR MAS NMR (high-resolution magic-angle spinning nuclear magnetic resonance) spectroscopy technique was combined with standard histological examinations to investigate the metabolic features of high-grade serous ovarian cancer (HGSOC) with a special focus on the relation between a metabolic profile and a cancer cell fraction. The studied group consisted of 44 patients with HGSOC and 18 patients with benign ovarian tumors. Normal ovarian tissue was also excised from 13 control patients. The metabolic profiles of 138 tissue specimens were acquired on a Bruker Avance III 400 MHz spectrometer. The NMR spectra of the HGSOC samples could be discriminated from those acquired from the non-transformed tissue and were shown to depend on tumor purity. The most important features that differentiate the samples with a high fraction of cancer cells from the samples containing mainly fibrotic stroma are the increased intensities in the spectral regions corresponding to phosphocholine/glycerophosphocholine, phosphoethanolamine/serine, threonine, uridine nucleotides and/or uridine diphosphate (UDP) nucleotide sugars. Higher levels of glutamine, glutamate, acetate, lysine, alanine, leucine and isoleucine were detected in the desmoplastic stroma within the HGSOC lesions compared to the stroma of benign tumors. The HR MAS NMR analysis of the metabolic composition of the epithelial and stromal compartments within HGSOC contributes to a better understanding of the disease's biology.

Abstract 137: Increased activity of protein kinase A is sufficient to cause fibrolamellar carcinoma

Abstract Tumor cells of almost all patients with fibrolamellar carcinoma (FLC) have a somatic mutation, a ~400 kB deletion on one copy of chromosome 19 that results in a fusion transcript of DNAJB1 to PRKACA, the catalytic subunit of protein kinase A. The resulting fusion oncoprotein, DNAJB1::PRKACA, has kinase activity, and is required and sufficient for transformation. To understand the oncogenesis of this tumor and to help identify potential therapeutic targets, we explored the pathways of pathogenesis mediated by the aberrant kinase. We explored three mechanisms that might explain transformation by the oncogenic kinase: - A difference in the substrate specificity of DNAJB1::PRKACA kinase versus native PRKACA kinase. - A difference in the interactome of DNAJB1::PRKACA kinase versus native PRKACA kinase. - An increase of total catalytic kinase activity (DNAJB1::PRKACA + PRKACA) versus the native PRKACA condition. We found, comparing cytosolic extracts of tumor and normal liver cells, that there are differences in the substrate specificity of the DNAJB1::PRKACA kinase. Additionally, such comparisons revealed differences in the interactions between the catalytic subunit of the kinase and cytosolic components. We also demonstrated a consistent increase in total PRKACA catalytic subunit in the FLC tumor, relative to the adjacent nontransformed tissue. Further, there is an increase in free, unregulated catalytic activity in the tumor cells and a change in the localization of the catalytic subunit in the tumor cells. Additionally, we have found that this increase in free catalytic activity is sufficient to account for the changes in the transcriptome in tumor cells of FLC patients. Importantly, enhanced expression in hepatocytes of either DNAJB1::PRKACA kinase or native PRKACA kinase caused very similar changes in the transcriptome, and the resultant transcriptomes closely resembled that of tumor cells from FLC patients. This suggests that the DNAJB1 domain is dispensable and not critical for transformation. In our investigation of patient tumors we found two rare and different subclasses of FLC that are indistinguishable from “classic” FLC, based on their transcriptome and based on their drug response profiles. Importantly, both subclasses are associated with changes of PRKACA, but neither involves the DNAJB1 domain. Thus, the DNAJB1 domain is not a critical component of transformation, and the significant driver is an increase of the cellular catalytic activity. Citation Format: Mahsa Shirani, Michael Tomasini, Solomon Levin, soeren heissel, Henrik Molina, Ype De Jong, charles Rice, Philip Coffino, Barbara Lyons, Sanford Simon. Increased activity of protein kinase A is sufficient to cause fibrolamellar carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 137.

FEATURES OF COLLAGENASE GENE EXPRESSION IN BREAST CANCER TISSUE:AN OPEN DATABASES ANALYSIS

Summary. Breast cancer (BCa) is the most common cancer among women both in Ukraine and in the world. Extracellular matrix remodeling has been shown to play a crucial role in tumor progression. Collagenases are one of the main drivers of this process, providing collagen degradation and directly affecting the invasion and metastasis of neoplastic cells. Aim: to study the features of collagenase gene expression and their regulatory factors in BC tissue as possible drivers of tumor growth. Objects and methods: a comparison of collagenase gene expression levels in normal and malignant breast tissue was performed using the GEPIA, UALCAN, and TNMplot resources. The methylation levels of collagenase gene promoters were determined using the UALCAN database. The identification of microRNAs and transcription factors involved in the regulation of collagenase expression was performed based on the information provided on the miRNet v2.0 platform using the TarBase v.8.0 and JASPAR databases. The miRNA level study was performed using the miR-TV online resource. Results: it was found that BCa tissue is characterized by significantly higher MMP1, MMP8, and MMP13 mRNA expression levels compared to normal breast tissue. It was demonstrated that the methylation levels of MMP1 and MMP13 promoters in tumor cells were significantly lower compared to non-transformed breast cells. Using the TarBase v.8.0 and JASPAR databases, transcription factors and miRNAs involved in the regulation of MMP1, MMP8, and MMP13 expression were identified. Analysis of the expression levels of miRNAs involved in the regulation of collagenase expression showed that the levels of miR-155-5p, miR-200b-3p, and miR-210-5p in BCa tissue were 2.26 (p = 2.2e-16), 2.95 (p = 2.2e-16), and 5.90 (p = 2.2e-16) times higher, respectively, compared to non-transformed breast tissue. It was shown that BC tissues compared to healthy donor tissues were characterized by significantly lower expression levels of miR-100-5p, miR-127-3p, and miR-539-5p by 4.19 (p = 2.2e-16), 2.05 (p = 3.9e-12), and 1.70 (p = 2.5e-5), respectively. Conclusions: the obtained results indicate the involvement of collagenases in the development and progression of malignant tumors and indicate the need for further research on their role in the formation of the aggressive potential of BC.

Expression of AhR-regulated miRNAs in non-small cell lung cancer in smokers and never smokers.

Smoking is a risk factor for non-small cell lung cancer (NSCLC). The most common subtypes of NSCLC are lung adenocarcinoma (LAC) and squamous cell carcinoma (SCC). The cigarette smoke contains aryl hydrocarbon receptor (AhR) ligands, such as benzo(a)pyrene (BaP). By activating the AhR, BaP can change the expression of many genes, including miRNA-encoding genes. In this study, we have evaluated the expression of few miRNAs potentially regulated by AhR (miR-21, -342, -93, -181a, -146a), as well as CYP1A1, a known AhR target gene, in lung tumor samples from smoking (n=40) and non-smoking (n=30) patients with LAC and from smoking patients with SCC (n=40). We have also collected macroscopically normal lung tissue >5 cm from the tumor margin. We compared the obtained data on the miRNA expression in tumors with data from The Cancer Genome Atlas (TCGA). We found that in 76.7% of non-smoking LAC patients, CYP1A1 mRNA was not detected in tumor and normal lung tissues, while in smoking patients, CYP1A1 expression was detected in tumors in almost half of the cases (47.5% for SCC and 42.5% for LAC). The expression profile of AhR-regulated miRNAs differed between LAC and SCC and depended on the smoking status. In LAC patients, the expression of oncogenic miRNA-21 and miRNA-93 in tumors was higher than in normal lung tissue from the same patients. However, in SCC patients from our sample, the levels of these miRNAs in tumor and non-transformed lung tissue did not differ significantly. The results of our studies and TCGA data indicate that the expression levels of miRNA-181a and miRNA-146a in LAC are associated with smoking: expression of these miRNAs was significantly lower in tumors of smokers. It is possible that their expression is regulated by AhR and AhRR (AhR repressor), and inhibition of AhR by AhRR leads to a decrease in miRNA expression in tumors of smoking patients. Overall, these results confirm that smoking has an effect on the miRNA expression profile. This should be taken into account when searching for new diagnostic and therapeutic targets for NSCLC.

Disruption of proteome by an oncogenic fusion kinase alters metabolism in fibrolamellar hepatocellular carcinoma.

Fibrolamellar hepatocellular carcinoma (FLC) is a usually lethal primary liver cancer driven by a somatic dysregulation of protein kinase A.We show that the proteome of FLC tumors is distinct from that of adjacent nontransformed tissue. These changes can account for some of the cell biological and pathological alterations in FLC cells, including their drug sensitivity and glycolysis. Hyperammonemic encephalopathy is a recurrent problem in these patients, and established treatments based on the assumption of liver failure are unsuccessful. We show that many of the enzymes that produce ammonia are increased and those that consume ammonia are decreased. We also demonstrate that the metabolites of these enzymes change as expected. Thus, hyperammonemic encephalopathy in FLC may require alternative therapeutics.

FGFR2 Controls Growth, Adhesion and Migration of Nontumorigenic Human Mammary Epithelial Cells by Regulation of Integrin β1 Degradation

The role of fibroblast growth factor receptor 2 (FGFR2), an important mediator of stromal paracrine and autocrine signals, in mammary gland morphogenesis and breast cancer has been extensively studied over the last years. However, the function of FGFR2 signalling in the initiation of mammary epithelial oncogenic transformation remains elusive. Here, FGFR2-dependent behaviour of nontumorigenic model of mammary epithelial cells was studied. In vitro analyses demonstrated that FGFR2 regulates epithelial cell communication with extracellular matrix (ECM) proteins. Silencing of FGFR2 significantly changed the phenotype of cell colonies in three-dimensional cultures, decreased integrins α2, α5 and β1 protein levels and affected integrin-driven processes, such as cell adhesion and migration. More detailed analysis revealed the FGFR2 knock-down-induced proteasomal degradation of integrin β1. Analysis of RNA-seq databases showed significantly decreased FGFR2 and ITGB1 mRNA levels in breast tumour samples, when compared to non-transformed tissues. Additionally, high risk healthy individuals were found to have disrupted correlation profiles of genes associated with FGFR2 and integrin signalling, cell adhesion/migration and ECM remodelling. Taken together, our results strongly suggest that FGFR2 loss with concomitant integrin β1 degradation is responsible for deregulation of epithelial cell-ECM interactions and this process may play an important role in the initiation of mammary gland epithelial tumorigenesis.

Triple-negative Breast Cancer: Identification of circRNAs With Efficacy in Preclinical In Vivo Models.

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with insufficient options for therapy. In order to identify new targets and treatment modalities we searched the literature for circular RNAs (circRNAs) which mediate efficacy in TNBC-related in vivo preclinical models. In addition to 5 down-regulated circRNAs which modulate tumor-suppressive pathways, we identified 15 up-regulated circRNAs. Down- and up-regulated refers to expression in corresponding non-transformed cells and tissues. The up-regulated circRNAs comprise five transmembrane receptors and secreted proteins as targets, five transcription factors and transcription-associated targets, four cell-cycle related circRNAs and one involved in paclitaxel resistance. In this review article we discuss drug-discovery related aspects and modalities of therapeutic intervention. Down-regulated circRNAs can be reconstituted by re-expression of corresponding circRNAs in tumor cells or up-regulation of corresponding targets. Up-regulated circRNAs can be inhibited by small-interfering RNA (siRNA) or short hairpin RNA (shRNA)-based approaches or inhibition of the corresponding targets with small molecules or antibody-related moieties.

Cellular transformation promotes the incorporation of docosahexaenoic acid into the endolysosome-specific lipid bis(monoacylglycerol)phosphate in breast cancer

Bis(monoacylglycero)phosphates (BMPs), a class of lipids highly enriched within endolysosomal organelles, are key components of the lysosomal intraluminal vesicles responsible for activating sphingolipid catabolic enzymes. While BMPs are understudied relative to other phospholipids, recent reports associate BMP dysregulation with a variety of pathological states including neurodegenerative diseases and lysosomal storage disorders. Since the dramatic lysosomal remodeling characteristic of cellular transformation could impact BMP abundance and function, we employed untargeted lipidomics approaches to identify and quantify BMP species in several in vitro and in vivo models of breast cancer and comparative non-transformed cells and tissues. We observed lower BMP levels within transformed cells relative to normal cells, and consistent enrichment of docosahexaenoic acid (22:6) fatty acyl chain-containing BMP species in both human- and mouse-derived mammary tumorigenesis models. Our functional analysis points to a working model whereby 22:6 BMPs serve as reactive oxygen species scavengers in tumor cells, protecting lysosomes from oxidant-induced lysosomal membrane permeabilization. Our findings suggest that breast tumor cells might divert polyunsaturated fatty acids into BMP lipids as part of an adaptive response to protect their lysosomes from elevated reactive oxygen species levels, and raise the possibility that BMP-mediated lysosomal protection is a tumor-specific vulnerability that may be exploited therapeutically.

Cell differentiation modifies the p53 transcriptional program through a combination of gene silencing and constitutive transactivation

The p53 transcription factor is a master regulator of cellular responses to stress that is commonly inactivated in diverse cancer types. Despite decades of research, the mechanisms by which p53 impedes tumorigenesis across vastly different cellular contexts requires further investigation. The bulk of research has been completed using in vitro studies of cancer cell lines or in vivo studies in mouse models, but much less is known about p53 action in diverse non-transformed human tissues. Here, we investigated how different cellular states modify the p53 transcriptional program in human cells through a combination of computational analyses of publicly available large-scale datasets and in vitro studies using an isogenic system consisting of induced pluripotent stem cells (iPSCs) and two derived lineages. Analysis of publicly available mRNA expression and genetic dependency data demonstrated wide variation in terms of expression and function of a core p53 transcriptional program across various tissues and lineages. To monitor the impact of cell differentiation on the p53 transcriptome within an isogenic cell culture system, we activated p53 by pharmacological inhibition of its negative regulator MDM2. Using cell phenotyping assays and genome wide transcriptome analyses, we demonstrated that cell differentiation confines and modifies the p53 transcriptional network in a lineage-specific fashion. Although hundreds of p53 target genes are transactivated in iPSCs, only a small fraction is transactivated in each of the differentiated lineages. Mechanistic studies using small molecule inhibitors and genetic knockdowns revealed the presence of two major regulatory mechanisms contributing to this massive heterogeneity across cellular states: gene silencing by epigenetic regulatory complexes and constitutive transactivation by lineage-specific transcription factors. Altogether, these results illuminate the impact of cell differentiation on the p53 program, thus advancing our understanding of how this tumor suppressor functions in different contexts.

Extending Omega 3/6 Fatty Acid Pathway in Arabidopsis thaliana using Microalgal Gene Δ6Des for Stearidonic acid and Dihomo-γ-linolenic acid Production

• Microalgal gene Δ6Des was cloned in a binary vector pCAMBIA1303. • F 1 transgenic plants having Δ6Des were viable at a concentration of 25 mg/L of hygromycin medium • Transgenic Arabidopsis thaliana showed novel ω3/6 fatty acids SDA (0.58%) and DGLA (25. 34%) To enhance the quality and quantity of oils in plant systems, specific candidate genes such as desaturase and elongase that can extend the biosynthetic pathways of very long chain poly unsaturated fatty acids (VLCPUFAs) are essential. In general, plant systems are capable of synthesizing essential fatty acids (EFAs). However, incorporation of a preliminary gene, Δ6Desaturase ( Δ6Des ), in the fatty acid biosynthetic pathway will elongate the pathway further to produce successive fatty acids. In this study, Δ6Des gene extracted from the marine microalga Isochrysis sp. was used to extend the omega (ω) 3/6 fatty acid biosynthetic pathway in a model plant Arabidopsis thaliana using Agrobacterium -mediated genetic transformation. Hygromycin-resistant plants were (25 mg/L) used for GUS and GFP assays and for molecular confirmation. GUS assay showed an intense blue color in F 1 transgenic A. thaliana plant tissues grown in the selection medium, which confirmed the presence of GUS gene in the T-DNA region, whereas non-transformed plant tissues such as leaf or stem did not show any blue color. GFP analysis also showed a green fluorescent color in tissues such as leaf, stem, and floral parts of F1 transgenic A. thaliana plants, which confirmed the presence of T-DNA. PCR and Southern blotting analyses also clearly showed the presence of Δ6Des in the T-DNA region of the F 1 transgenic plants. The fatty acid profile of F 1 transgenic plants showed the production of new fatty acids such as stearidonic acid (SDA-0.58%) and dihomo-γ-linolenic acid (DGLA-25.34%) that were not observed in non-transformed control plants. All these results showed the synthesis of new fatty acids in the transgenic plant, which proved that PUFA biosynthetic pathway can be extended in oilseed plants if specific genes are introduced through genetic transformation. This is the first study to report the productions of new fatty acids like SDA and DGLA in A. thaliana using Δ6Des gene from marine microalga Isochrysis sp.

LC3B, mTOR, AMPK Are Molecular Targets for Neoadjuvant Chemotherapy in Gastric Cancers.

Autophagy plays a dual role in oncogenesis processes. On one hand, autophagy enhances the cell resistance to oncogenic factors, and on the other hand, it participates in the tumor progression. The aim of the study was to find the associations between the effectiveness of the FLOT regimen in resectable gastric cancers (GCs) with the key autophagy-related proteins. Materials and Methods: The study included 34 patients with morphologically verified gastric cancer. All patients had FLOT neoadjunvant chemotherapy (NACT) (fluorouracil, leucovorin, oxaliplatin, and docetaxel) followed by gastrectomy. The studied tissue material was the non-transformed and tumor tissues obtained during diagnostic video gastroscopy in patients before the start of the combined treatment and after surgical treatment, frozen after collection. The LC3B, mTOR, and AMPK expression was determined by real-time PCR. The content of the LC3B protein was determined by Western blotting analysis. Results: The mRNA level and the content of the LC3B protein were associated with the tumor stage and the presence of signet ring cells. The AMPK mRNA level was increased in patients with the T4N0-2M0 stage by 37.7 and 7.33 times, which was consequently compared with patients with the T2N0M0 and T3N0-1M0 stages. The opposite changes in the mTOR and AMPK in the GCs before anti-cancer therapy were noted. The tumor size and regional lymph node affections were associated with a decrease in the mTOR mRNA level. A decrease in the mTOR expression was accompanied by an increase in the AMPK expression in the GCs. The mTOR expression was reduced in patients with a cancer spreading; in contrast, AMPK grew with the tumor size. There was an increase in the LC3B expression, which can probably determine the response to therapy. An increase in LC3B mRNA before the start of treatment and the protein content in cancers after NACT with a decrease in therapy effectiveness was recorded. There was an increase in the protein level in patients with partial regression and stabilization by 3.65 and 5.78 times, respectively, when compared with patients with complete tumor regression was noted. Conclusions: The anticancer effectiveness in GCS is down to the LC3B, mTOR, and AMPK expression. These were found to be entire molecular targets affecting the cancer progression and metastasis as well as the NACT effectiveness.

Abstract 2020: Investigation of CYP450 enzymes as therapeutic targets in rhabdomyosarcoma

Abstract Introduction: Rhabdomyosarcoma (RMS) is a rare soft tissue sarcoma (STS) that predominantly affects children and teenagers. It is the most frequent STS in children and accounts for around 5-8% of total childhood cancers. The improvement of chemotherapeutic regimens has raised RMS survival chances over the last decades. However, the mortality rate remains exceptionally high in high-risk RMS patients. Duocarmycins have arisen as an opportunity for targeted therapy in cancer. These ultrapotent anticancer agents have been reengineered to generate bioprecursors that are selectively activated bycertain cytochrome P450 (CYP) isoforms (e.g. CYP1A1, CYP1B1, CYP2W1). The overexpression of these isoforms in tumors provides the possibility to locoregionally bioactivate duocarmycin prodrugs only in the tumor site. Previous studies have shown that duocarmycins can be chemically modified and deactivated by removal of a hydroxyl group in the pharmacophore, which can be reinstalled by CYPsto generate a potent DNA-targeted cytotoxic metabolite. In the past, a consistent CYP2W1overexpression in patient-derived RMS biopsies as compared to matched, non-transformed tissue was revealed. Results: Ongoing studies are focused on measuring CYP1A1, CYP1B1 and CYP2W1 expression levels in RMS cell lines and in three-dimensional spheroids as well as evaluating the antiproliferative activity of duocarmycin bioprecursors in these models. With the exception of RH30 cells (IC50=0.2µM forICT2700) the IC50 for CYP1A1- and CYP2W1-bioactivated duocarmycins (ICT2700 and ICT2706,respectively) lie in the low micromolar range in RMS monolayer cultures, suggesting that CYP1A1 andCYP2W1 might not be a suitable target in these 2D cancer models. Consistently, only RH30 cells displayed a high CYP1A1 expression in monolayer cultures among the RMS cell line panel, and noCYP2W1 expression could be identified. However, preliminary data suggests that CYP1A1 and CYP2W1enzymes might be restored when spheroids are generated from RMS cell lines. A functional 7-ethoxyresorufin-O-deethylase (EROD) assay has been validated to analyze CYP1A1- and CYP1B1-specific enzymatic activity in RMS cell lines. Vorinostat (SAHA) is an epigenetic drug currently used in the clinic for cancer treatment, and it has been associated with modulatory effects on CYP1expression. Our data suggests cell line-dependent synergistic or antagonistic effects of SAHA when combined with ICT2700, and these correlate with SAHA-induced CYP1A1 upregulation and downregulation respectively at both gene and protein levels. Conclusion: Evaluation of CYP target expression in RMS is being established to assess if duocarmycin bioprecursorscan be progressed as a novel type of therapy in RMS. Interestingly, CYP450 expression in RMS cell lines seems to vary depending on the complexity of the in vitro model used. Citation Format: Enric Arasanz Picher, Klaus Pors. Investigation of CYP450 enzymes as therapeutic targets in rhabdomyosarcoma [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 2020.

Abstract 2494: Pathogenesis of fibrolamellar: Proteome and phosphome of an oncokinase driven cancer

Abstract Fibrolamellar hepatocellular carcinoma, FLC, is a usually lethal cancer affecting children, and young adults. We have shown that all patients have a disruption in the ecology of protein kinase A activity. Hundreds of patients tested have a fusion of the first exon of DNABJ1, a heat shock protein cofactor, to PRKACA, the catalytic subunit of protein kinase A and expression of this DNAJB1-PRKACA fusion oncokinase is sufficient to produce the tumor. One patient is missing the regulatory subunit of protein kinase A and three patients have a fusion of the first exon of a different protein, ATP1B1, to the catalytic subunit of protein kinase A. We characterized the proteome and phosphoproteome of FLC cells relative to adjacent normal tissue. The changes were sufficiently characteristic to identify cell extracts from FLC, based solely on the proteome or phosphoproteome, and distinguishable from other tumor or normal liver. By calibrating protein level we found that tumor cells have an increase of catalytic subunit to such an extent as to exceed the capacity of protein kinase A regulatory subunits. This has two implications. First, there is free catalytic subunit that is unregulated, creating a high basal level of kinase activity. Second, the catalytic subunit is no longer localized by tethering to the regulatory subunit. Thus, the catalytic subunit has access to novel substrates. As an independent confirmation, we found the free basal kinase activity was higher in FLC cells. As a further test, we showed free catalytic subunit, that is not conjugated to regulatory subunit, is higher in FLC cells. We next tested whether these changes were solely due to overexpression of the catalytic subunit or if there was some additional change in the intrinsic activity of the kinase as a result of the fusion. We purified, without using an affinity tag, either PRKACA (which is myristoylated), DNAJB1-PRKACA, and PRKACA which was not myristoylated (the DNAJB1-PRKACA is not myristoylated). As a further control we also used the PRKACAL206R mutation, which does not engage regulatory subunits and is present in some forms of Cushing’s disease. We purified cytosol from human liver, blocked activity of all the endogenous kinases, and added our purified kinase. Mass spectrometry was then used to identify all newly phosphorylated proteins. While many proteins were equally phosphorylated by all four kinases (PRKACA, DNAJB1-PRKACA, PRKACA not myristoylated, PRKACAL206R) there were some distinct differences. From an analysis of these we found alterations in the optimal recognition sequence for phosphorylation for each variant of the kinase. Significantly, when we examined the human tissue data, we found many proteins that were phosphorylated by the DNAJB1-PRKACA in vitro were also phosphorylated in patient tumor tissue, but not in adjacent non-transformed tissue. This validated these observations of altered phosphorylation from the in vitro assays. Citation Format: Solomon Levin, Mahsa Shironi, Melissa Jarmel, Michael Tomasini, Bassem Shebl, Tova Finkelstein, David Requena, Soeren Heissel, Henrik Molina, Philip Coffino, Barbara Lyons, Sanford M. Simon. Pathogenesis of fibrolamellar: Proteome and phosphome of an oncokinase driven cancer [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 2494.

Metabolic Stress Adaptations Underlie Mammary Gland Morphogenesis and Breast Cancer Progression.

Breast cancers display dynamic reprogrammed metabolic activities as cancers develop from premalignant lesions to primary tumors, and then metastasize. Numerous advances focus on how tumors develop pro-proliferative metabolic signaling that differs them from adjacent, non-transformed epithelial tissues. This leads to targetable oncogene-driven liabilities among breast cancer subtypes. Other advances demonstrate how microenvironments trigger stress-response at single-cell resolution. Microenvironmental heterogeneities give rise to cell regulatory states in cancer cell spheroids in three-dimensional cultures and at stratified terminal end buds during mammary gland morphogenesis, where stress and survival signaling juxtapose. The cell-state specificity in stress signaling networks recapture metabolic evolution during cancer progression. Understanding lineage-specific metabolic phenotypes in experimental models is useful for gaining a deeper understanding of subtype-selective breast cancer metabolism.

Reduced Shmt2 Expression Impairs Mitochondrial Folate Accumulation and Respiration, and Leads to Uracil Accumulation in Mouse Mitochondrial DNA

BackgroundAdequate cellular thymidylate (dTMP) pools are essential for preservation of nuclear and mitochondrial genome stability. Previous studies have indicated that disruption in nuclear dTMP synthesis leads to increased uracil misincorporation into DNA, affecting genome stability. To date, the effects of impaired mitochondrial dTMP synthesis in nontransformed tissues have been understudied. ObjectivesThis study aimed to determine the effects of decreased serine hydroxymethyltransferase 2 (Shmt2) expression and dietary folate deficiency on mitochondrial DNA (mtDNA) integrity and mitochondrial function in mouse tissues. MethodsLiver mtDNA content, and uracil content in liver mtDNA, were measured in Shmt2+/− and Shmt2+/+ mice weaned onto either a folate-sufficient control diet (2 mg/kg folic acid; C) or a modified diet lacking folic acid (0 mg/kg folic acid) for 7 wk. Shmt2+/− and Shmt2+/+ mouse embryonic fibroblast (MEF) cells were cultured in defined culture medium containing either 0 or 25 nM folate (6S-5-formyl-tetrahydrofolate, folinate) to assess proliferative capacity and mitochondrial function. Chi-square tests, linear mixed models, and 2-factor ANOVA with Tukey post hoc analyses were used to analyze data. ResultsShmt2+/− mice exhibited a 48%–67% reduction in SHMT2 protein concentrations in tissues. Interestingly, Shmt2+/− mice consuming the folate-sufficient C diet exhibited a 25% reduction in total folate in liver mitochondria. There was also a >20-fold increase in uracil in liver mtDNA in Shmt2+/− mice consuming the C diet, and dietary folate deficiency also increased uracil content in mouse liver mtDNA from both Shmt2+/+ and Shmt2+/− mice. Furthermore, decreased Shmt2 expression in MEF cells reduced cell proliferation, mitochondrial membrane potential, and oxygen consumption rate. ConclusionsThis study demonstrates that Shmt2 heterozygosity and dietary folate deficiency impair mitochondrial dTMP synthesis in mice, as evidenced by the increased uracil in mtDNA. In addition, Shmt2 heterozygosity impairs mitochondrial function in MEF cells. These findings suggest that elevated uracil in mtDNA may impair mitochondrial function.

Grading of endometrial cancer using 1H HR-MAS NMR-based metabolomics

The tissue metabolomic characteristics associated with endometrial cancer (EC) at different grades were studied using high resolution (400 MHz) magic angle spinning (HR-MAS) proton spectroscopy. The metabolic profiles were obtained from 64 patients (14 with grade 1 (G1), 33 with grade 2 (G2) and 17 with grade 3 (G3) tumors) and compared with the profile acquired from 10 patients with the benign disorders. OPLS-DA revealed increased valine, isoleucine, leucine, hypotaurine, serine, lysine, ethanolamine, choline and decreased creatine, creatinine, glutathione, ascorbate, glutamate, phosphoethanolamine and scyllo-inositol in all EC grades in reference to the non-transformed tissue. The increased levels of taurine was additionally detected in the G1 and G2 tumors in comparison to the control tissue, while the elevated glycine, N-acetyl compound and lactate—in the G1 and G3 tumors. The metabolic features typical for the G1 tumors are the increased dimethyl sulfone, phosphocholine, and decreased glycerophosphocholine and glutamine levels, while the decreased myo-inositol level is characteristic for the G2 and G3 tumors. The elevated 3-hydroxybutyrate, alanine and betaine levels were observed in the G3 tumors. The differences between the grade G1 and G3 malignances were mainly related to the perturbations of phosphoethanolamine and phosphocholine biosynthesis, inositol, betaine, serine and glycine metabolism. The statistical significance of the OPLS-DA modeling was also verified by an univariate analysis. HR-MAS NMR based metabolomics provides an useful insight into the metabolic reprogramming in endometrial cancer.

G\u03b115 in early onset of pancreatic ductal adenocarcinoma

The GNA15 gene is ectopically expressed in human pancreatic ductal adenocarcinoma cancer cells. The encoded Gα15 protein can promiscuously redirect GPCR signaling toward pathways with oncogenic potential. We sought to describe the distribution of GNA15 in adenocarcinoma from human pancreatic specimens and to analyze the mechanism driving abnormal expression and the consequences on signaling and clinical follow-up. We detected GNA15 expression in pre-neoplastic pancreatic lesions and throughout progression. The analysis of biological data sets, primary and xenografted human tumor samples, and clinical follow-up shows that elevated expression is associated with poor prognosis for GNA15, but not any other GNA gene. Demethylation of the 5′ GNA15 promoter region was associated with ectopic expression of Gα15 in pancreatic neoplastic cells, but not in adjacent dysplastic or non-transformed tissue. Down-modulation of Gα15 by shRNA or CRISPR/Cas9 affected oncogenic signaling, and reduced adenocarcimoma cell motility and invasiveness. We conclude that de novo expression of wild-type GNA15 characterizes transformed pancreatic cells. The methylation pattern of GNA15 changes in preneoplastic lesions coincident with the release a transcriptional blockade that allows ectopic expression to persist throughout PDAC progression. Elevated GNA15 mRNA correlates with poor prognosis. In addition, ectopic Gα15 signaling provides an unprecedented mechanism in the early steps of pancreas carcinogenesis distinct from classical G protein oncogenic mutations described previously in GNAS and GNAQ/GNA11.

Polyester Polymeric Nanoparticles as Platforms in the Development of Novel Nanomedicines for Cancer Treatment

Simple SummaryDespite the existence of powerful therapeutic agents, cancer is still an incurable disease in many clinical scenarios. In this regard, nanomedicine and particularly polymeric nanoparticles have raised attention as a manner to improved drug delivery. Polymeric nanoparticles can optimize existent compounds or be used to improve the formulation for novel therapeutics. In this article the advantages and disadvantages of polymeric nanoparticles will be discussed, and current nanodevices, raw materials for their formulation, methods of formulation, and polymeric nanoparticles in clinical investigations will be reviewed. Finally, options for improvement and clinical applications will be suggested.Many therapeutic agents have failed in their clinical development, due to the toxic effects associated with non-transformed tissues. In this context, nanotechnology has been exploited to overcome such limitations, and also improve navigation across biological barriers. Amongst the many materials used in nanomedicine, with promising properties as therapeutic carriers, the following one stands out: biodegradable and biocompatible polymers. Polymeric nanoparticles are ideal candidates for drug delivery, given the versatility of raw materials and their feasibility in large-scale production. Furthermore, polymeric nanoparticles show great potential for easy surface modifications to optimize pharmacokinetics, including the half-life in circulation and targeted tissue delivery. Herein, we provide an overview of the current applications of polymeric nanoparticles as platforms in the development of novel nanomedicines for cancer treatment. In particular, we will focus on the raw materials that are widely used for polymeric nanoparticle generation, current methods for formulation, mechanism of action, and clinical investigations.

Thermal Ablation of Colorectal Cancer Metastases Leads to Activation of Individual Cancer-Specific T Cell Immunity

Introduction: The underlying cellular mechanisms of successful immunotherapy are still insufficiently characterized. Especially, priming of tumor-specific T cells against relevant antigens and in situ tumor-recognition is crucial for therapy success in the development of active immunotherapeutic approaches, but remain a serious challenge. Thermal ablation of cancer, e.g. percutaneous radiofrequency ablation (RFA) is a well-established treatment option, particularly for patients with contraindications for surgical resection or in non-resectable primary or secondary liver cancers. RFA induces local tumor destruction by coagulation necrosis, leading to the release of danger signals (e.g. heat shock proteins) and cellular content that can induce and stimulate adaptive and innate immune responses, including tumor-antigen specific T cells. By breaking local immune tolerance, RFA may support the development of antigen-specific anti-tumor responses. Here, we analyzed patient-individual immune responses against autologous HLA-presented tumor antigens after RFA treatment.Materials and Methods: Patients (n=6) with liver metastases of colorectal carcinoma (CRC) in different liver segments were included. First, non-resectable manifestations were ablated using RFA. Subsequently, patients underwent metachronous liver surgery for resectable residual tumors. Using surgical specimens, immunopeptidome analyses of tumor and corresponding non-malignant liver tissues were performed by uHPLC-coupled tandem mass spectrometry (MS) after immunoprecipitation of HLA-ligands. Ligandome data were combined with results from whole transcriptome sequencing (WTS) in order to select for patient-specific HLA-ligands potentially relevant for the patient's individual tumor. Furthermore, identified peptides were compared with an extensive in house database of HLA ligands, derived from different non-transformed tissues including non-malignant colon (NMC) specimens. Peripheral blood mononuclear cells (PBMC) obtained at pre-defined time points before and after RFA and surgery were stimulated in vitro with these T cell epitope candidates. Functional T cell responses were characterized by intracellular cytokine staining (ICS).Results: Combining WTS data and analyses of autologous tumor-exclusive HLA-ligandomes, we selected 32 individual T cell epitope candidates for the respective patients. Antigen-specific T cells could be detected against approx. one third of the candidate epitopes. Both boosting of pre-existing as well as newly induced T cell responses against these epitopes could be detected after RFA. With regard to pre-existing immune responses, CD8+ and CD4+ T cell reactivities could be demonstrated against both HLA class I and class II epitopes. In 4/6 patients (66%) analyzed, de novo induced antigen-specific T cells could be detected after RFA. These reactivities comprised CD8+ as well as CD4+ T cells. Of particular interest, in one patient (diagnosed with mCRC) antigen-specific CD4+ T cells against a mutated HLA-class II peptide were detectable, which were induced by RFA. Of note, this epitope could only be detected on the transcriptome level but not directly as an HLA-ligand by MS.Conclusions: Employing this individualized approach, tumor-antigen specific T cells were more frequently detected as compared to our previous observations employing broadly expressed tumor-associated antigens. These findings suggest that RFA leads to induction of antigen-specific T cells more frequently than previously appreciated, and interestingly also encompasses responses against neo-antigens. The detected immune responses induced by RFA themselves may not be solely sufficient for effectively rejecting established tumors. However, these findings justify the clinical investigation of combinatorial therapies, using immune stimulatory agents or immune checkpoint inhibitors together with thermal ablation. DisclosuresNo relevant conflicts of interest to declare.