Immunohistochemical quantification of the cobalamin transport protein, cell surface receptor and Ki-67 in naturally occurring canine and feline malignant tumors and in adjacent normal tissues

Radiation-Activated Cobalamin-Kinase Inhibitors for Treatment of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most dismal diagnoses that a patient can receive. PDAC is extremely difficult to treat, as drug delivery is challenging in part due to the lack of vascularization, high stromal content, and high collagen content of these tumors. We have previously demonstrated that attaching drugs to the cobalamin scaffold provides selectivity for tumors over benign cells due to a high vitamin demand in these rapidly growing cells and an overexpression of transcobalamin receptors in a variety of cancer types. Importantly, we have shown the ability to deliver cobalamin derivatives to orthotopic pancreas tumors. Tyrosine kinase inhibitors have shown promise in treating PDAC as well as other cancer types. However, some of these inhibitors suffer from drug resistance, and as such, their success has been diminished. With this in mind, we synthesized the tyrosine kinase inhibitors erlotinib (EGFR) and dasatinib (Src) that are attached to this cobalamin platform. Both of these cobalamin-drug conjugates cause visible light-induced apoptosis, and the cobalamin-erlotinib conjugate (2) causes X-ray-induced apoptosis in MIA PaCa-2 cells. Both visible light and X-rays provide spatial control of drug release; however, utilizing X-ray irradiation offers the advantage of deeper tissue penetration. Therefore, we explored the utilization of 2 as a synergistic therapy with radiation in athymic nude mice implanted with MIA PaCa-2 tumors. We discovered that the addition of 2 caused an enhanced reduction in tumor margins in comparison with radiation therapy alone. In addition, treatment with 2 in the absence of radiation caused no significant reduction in tumor size in comparison with the controls. The cobalamin technology presented here allows for the spatial release of drugs in conjunction with external beam radiation therapy, potentially allowing for more effective treatment of deep-seated tumors with less systemic side effects.

Prevalence of neoplasia and concurrent diseases in dogs and cats with hypercobalaminemia: A retrospective case-control study

BACKGROUND

Hypercobalaminemia is infrequently reported in companion animals and is considered of low clinical significance. Recent studies have described its association with inflammatory, immune-mediated, endocrine, and neoplastic conditions in dogs and cats.

OBJECTIVES

We aimed to investigate the association between hypercobalaminemia and neoplasia in companion animals and to identify other concurrent diseases or clinicopathologic changes.

METHODS

This is a retrospective, case-control study. Medical records of patients with measured serum cobalamin concentration (2015-2020) and no history of prior supplementation were reviewed. Hypocobalaminemic animals were excluded. Variables were compared between groups (hypercobalaminemic vs. normocobalaminemic) using non-parametric statistics. Data are presented as median (range).

RESULTS

Thirty-five dogs and eight cats were hypercobalaminemic. At baseline, neoplasia was confirmed in 4/35 hypercobalaminemic dogs versus 11/70 control dogs (P = 0.77) and 0/8 hypercobalaminemic cats versus 3/16 control cats (P = 0.53). Cases without neoplasia at baseline were followed for 409 (13-1854) days (dogs, n = 78) and 395 (28-1670) days (cats, n = 21). During follow-up, neoplasia was diagnosed in 4/27 hypercobalaminemic dogs versus 3/51 control dogs (P = 0.23) and 1/8 hypercobalaminemic cats versus 0/13 control cats (P = 0.38). Pancreatitis was more frequent in hypercobalaminemic dogs (P = 0.006). Hypercobalaminemic dogs had higher serum total protein (P = 0.014), globulin (P = 0.001), and CRP (P = 0.032) concentrations and lower serum sodium (P = 0.012) and chloride (P = 0.033) concentrations than controls. Hypercobalaminemic cats had higher serum total protein concentrations than controls (P = 0.008).

CONCLUSION

Our results suggest that hypercobalaminemia is not associated with the presence or development of neoplasia in dogs and cats but may be associated with systemic inflammatory conditions, including pancreatitis, in dogs.

Group 1 metabotropic glutamate receptor expression defines a T cell memory population during chronic Toxoplasma infection that enhances IFN-gamma and perforin production in the CNS

Within the brain, a pro-inflammatory response is essential to prevent clinical disease due to Toxoplasma gondii reactivation. Infection in the immunocompromised leads to lethal Toxoplasmic encephalitis while in the immunocompetent, there is persistent low-grade inflammation which is devoid of clinical symptoms. This signifies that there is a well-balanced and regulated inflammatory response to T. gondii in the brain. T cells are the dominant immune cells that prevent clinical disease, and this is mediated through the secretion of effector molecules such as perforins and IFN-γ. The presence of cognate antigen, the expression of survival cytokines, and the alteration of the epigenetic landscape drive the development of memory T cells. However, specific extrinsic signals that promote the formation and maintenance of memory T cells within tissue are poorly understood. During chronic infection, there is an increase in extracellular glutamate that, due to its function as an excitatory neurotransmitter, is normally tightly controlled in the CNS. Here we demonstrate that CD8+ T cells from the T. gondii-infected brain parenchyma are enriched for metabotropic glutamate receptors (mGluR's). Characterization studies determined that mGluR+ expression by CD8+ T cells defines a distinct memory population at the transcriptional and protein level. Finally, using receptor antagonists and agonists we demonstrate mGluR signaling is required for optimal CD8+ T cell production of the effector cytokine IFNγ. This work suggests that glutamate is an important environmental signal of inflammation that promotes T cell function. Understanding glutamate's influence on T cells in the brain can provide insights into the mechanisms that govern protective immunity against CNS-infiltrating pathogens and neuroinflammation.

Impacts of some clinicopathodemography and colorectal tissues key cell cycle and mucin stabilizing molecules on the metastasis trend in colorectal cancer patients

BACKGROUND

We aimed to evaluate the various clinicopathodemographical, epidemiological, and molecular contributors to cumulatively worldwide metastatic colorectal cancer (CRC) in CRC patients from a highly populated area in northeastern Iran to pinpoint metastasis risk.

METHODS

A retrospective clinical material-based cohort including a total of 6260 registered CRC patients, of whom 3829 underwent surgery, from regional university hospitals, during 2006-2016, were analyzed for the clinicopathodemographical aspects of age, sex, stage of CRC, history of smoking, type 2 diabetes (T2D), hypertension, body mass index (BMI), familial/occupational status, post-surgery survival period and mRNA/protein expression of mucin stabilizer (B3GALNT2), mucin I (MUC1), key cell cycle molecules (i.e., P53 and Ki67), and MMR-related genes. Factors were set to estimate the risk of metastatic CRC and mortality.

RESULTS

Predominant adenocarcinomatous CRCs were found in colon. Post-surgery survival period of metastatic CRC patients was remarkably longer in patients aged > 50 compared to those aged < 50 years, and worse in females than males. B3GALNT2high, MUChigh, P53low, and Ki67high mRNA/protein expression in the metastatic stage III CRC along with T2D and hypertension were associated with increased metastasis/mortality, with more worsening in males, older, BMI > 25, urban residing, and employed individuals, indicative of non-genetic attributable factors.

CONCLUSION

B3GALNT2, MUC1, and "Ki67" can be used as promising biomarkers for prognosis and early diagnosis of increasingly/predominantly non-genetic/environmental originated metastatic CRCs.

Vitamin B12 in Cats: Nutrition, Metabolism, and Disease

Cobalamin is a water-soluble molecule that has an important role in cellular metabolism, especially in DNA synthesis, methylation, and mitochondrial metabolism. Cobalamin is bound by intrinsic factor (IF) and absorbed in the ileal tract. The IF in cats is synthesized exclusively by pancreatic tissue. About 75% of the total plasma cobalamin in cats is associated with transcobalamin II, while in this species, transcobalamin I is not present. In cats, the half-life of cobalamin is 11-14 days. Diagnostic biomarkers for B12 status in cats include decreased levels of circulating total cobalamin and increased levels of methylmalonic acid. The reference interval for serum cobalamin concentrations in cats is 290-1500 ng/L, and for the serum methylmalonic acid concentration, it is 139-897 nmol/L. Therapy for hypocobalaminemia mainly depends on the underlying disease. In some cases, subcutaneous or intramuscular injection of 250 μg/cat is empirically administered. In recent years, it has been demonstrated that oral cobalamin supplementation can also be used successfully in dogs and cats as a less invasive alternative to parental administration. This review describes the current knowledge regarding B12 requirements and highlights improvements in diagnostic methods as well as the role of hypocobalaminemia in its associated diseases.

Proposal for a New Diagnostic Histopathological Approach in the Evaluation of Ki-67 in GEP-NETs

Introduction: Studies have shown that the Ki-67 index is a valuable biomarker for the diagnosis, and classification of gastro-entero-pancreatic neuroendocrine tumors (GEP-NETs). We re-evaluated the expression of Ki-67 based on the intensity of the stain, basing our hypothesis on the fact that the Ki-67 protein is continuously degraded. Background: The aim was to evaluate whether a new scoring method would be more effective in classifying NETs by reducing staining heterogeneity. Methods: Patients with GEP-NET (n = 87) were analyzed. The classification difference between the two methods was determined. Results: The classification changed significantly when the Ki-67 semiquantal index was used. The percentage of G1 patients increased from 18.4% to 60.9%, while the G2 patients decreased from 66.7% to 29.9% and the G3 patients also decreased from 14.9% to 9.2%. Moreover, it was found that the traditional Ki-67 was not significantly related to the overall survival (OS), whereas the semiquantal Ki-67 was significantly related to the OS. Conclusions: The new quantification was a better predictor of OS and of tumor classification. Therefore, it could be used both as a marker of proliferation and as a tool to map tumor dynamics that can influence the diagnosis and guide the choice of therapy.

The avian retroviral receptor Tva mediates the uptake of transcobalamin bound vitamin B12 (cobalamin)

The Avian sarcoma and leukosis viruses (ASLVs) are important chicken pathogens. Some of the virus subgroups, including ASLV-A and K, utilize the Tva receptor for cell entrance. Though Tva was identified three decades ago, its physiological function remains unknown. Previously, we have noted an intriguing resemblance and orthology between the chicken gene coding for Tva and the human gene coding for CD320, a receptor involved in cellular uptake of transcobalamin (TC) in complex with vitamin B12/cobalamin (Cbl).Here we show that both the transmembrane and the glycosylphosphatidylinositol (GPI)-anchored form of Tva in the chicken cell line DF-1 promotes the uptake of Cbl with help of expressed and purified chicken TC. The uptake of TC-Cbl complex was monitored using an isotope- or fluorophore-labeled Cbl. We show that (i) TC-Cbl is internalized in chicken cells; and (ii) the uptake is lower in the Tva-knockout cells and higher in Tva-overexpressing cells when compared with wild type chicken cells. The relation between physiological function of Tva and its role in infection was elaborated by showing that infection with ASLV subgroups (targeting Tva) impairs the uptake of TC-Cbl, while this is not the case for cells infected with ASLV-B (not recognized by Tva). In addition, exposure of the cells to a high concentration of TC-Cbl alleviates the infection with Tva-dependent ASLV.IMPORTANCE: We demonstrate that the ASLV receptor Tva participates in the physiological uptake of TC-Cbl, because the viral infection suppresses the uptake of Cbl and vice versa. Our results pave the road for future studies addressing the issues: (i) whether a virus infection can be inhibited by TC-Cbl complexes in vivo; and (ii) whether any human virus employs the human TC-Cbl receptor CD320. In broader terms, our study sheds light on the intricate interplay between physiological roles of cellular receptors and their involvement in virus infection.

Immunoexpression and Prognostic Significance of Multidrug Resistance Markers in Feline Mammary Carcinomas

Feline mammary carcinomas (FMCs) are commonly characterized by high clinical aggressiveness and poor prognosis. FMCs share many features with the corresponding human disease, allowing the comparative investigation of tumour biology and therapeutic strategies, including multidrug resistance (MDR) mechanisms. Although transporting/binding proteins, including permeability glycoprotein (P-gp), lung resistance protein (LRP) and metallothionein (MT), are frequently associated with tumour aggressiveness and unresponsiveness to chemotherapy in human breast cancer, they have not been analysed in FMCs. We investigated the immunoexpression of P-gp, LRP and MT in FMCs and their correlation with clinicopathological parameters and overall survival (OS) time in 46 FMCs, with a median follow-up period of 289 days. These markers were co-expressed in 85% of tumours. P-gp was expressed in 93.4% of FMCs and was positively associated with tumour grade (P = 0.049). While unequivocally observed in all FMCs, LRP immunoexpression did not correlate with any clinicopathological parameters or OS. Expression of MT was significant in triple-negative basal- and normal-like molecular subtypes of FMCs (P = 0.023). The concurrent expression of MDR proteins indicates the potential existence of chemotherapy resistance-related mechanisms in FMCs. The positive association between P-gp and MT immunoexpression and aggressive phenotypes could open new therapeutic and translational strategies for FMCs.

Molecular evaluation of chronic restrain stress in mice model of non metastatic fibrosarcoma

Chronic stress is regarded as a significant factor in the etiology of the many diseases. Numerous methods have been developed through which the effect of chronic stress is examined. The aim of this study is to demonstrate the new experimental model for analysis of immuno-suppression induced by chronic restraint stress, through challenge with conditionally tumorigenic cell line BHK-21/C13. 20 male NMRI mice were randomly divided into 2 groups-control and experimental. Each mouse was subcutaneously inoculated with BHK-21/C13 cells. Stress in the experimental group was induced for 20 days. After the experiment, tumor masses were removed, and analyzed using histology and immunohistochemistry techniques. We found a statistically significant difference (p = 0.034) in tumor expression and tumor volumes (p = 0.0061) between groups, as well as in immunopositivity on Ki67, cytochrome C and matrix metalloproteinase 9. Absence of immune infiltrate was noticed in experimental, and the presence of inflammatory infiltrate at tumor invasion front in control group.

The Small Molecule Ephrin Receptor Inhibitor, GLPG1790, Reduces Renewal Capabilities of Cancer Stem Cells, Showing Anti-Tumour Efficacy on Preclinical Glioblastoma Models

Therapies against glioblastoma (GBM) show a high percentage of failure associated with the survival of glioma stem cells (GSCs) that repopulate treated tumours. Forced differentiation of GSCs is a promising new approach in cancer treatment. Erythropoietin-producing hepatocellular (Eph) receptors drive tumourigenicity and stemness in GBM. We tested GLPG1790, a first small molecule with inhibition activity versus inhibitor of various Eph receptor kinases, in preclinical GBM models using in vitro and in vivo assays. GLPG1790 rapidly and persistently inhibited Ephrin-A1-mediated phosphorylation of Tyr⁵⁸⁸ and Ser⁸⁹⁷, completely blocking EphA2 receptor signalling. Similarly, this compound blocks the ephrin B2-mediated EphA3 and EphB4 tyrosine phosphorylation. This resulted in anti-glioma effects. GLPG1790 down-modulated the expression of mesenchymal markers CD44, Sox2, nestin, octamer-binding transcription factor 3/4 (Oct3/4), Nanog, CD90, and CD105, and up-regulated that of glial fibrillary acidic protein (GFAP) and pro-neural/neuronal markers, βIII tubulin, and neurofilaments. GLPG1790 reduced tumour growth in vivo. These effects were larger compared to radiation therapy (RT; U251 and T98G xenografts) and smaller than those of temozolomide (TMZ; U251 and U87MG cell models). By contrast, GLPG1790 showed effects that were higher than Radiotherapy (RT) and similar to Temozolomide (TMZ) in orthotopic U87MG and CSCs-5 models in terms of disease-free survival (DFS) and overall survival (OS). Further experiments were necessary to study possible interactions with radio- and chemotherapy. GLPG1790 demonstrated anti-tumor effects regulating both the differentiative status of Glioma Initiating Cells (GICs) and the quality of tumor microenvironment, translating into efficacy in aggressive GBM mouse models. Significant common molecular targets to radio and chemo therapy supported the combination use of GLPG1790 in ameliorative antiglioma therapy.

Imaging Cobalamin Uptake within Malignant Breast Tumors In Vivo

PURPOSE

To image the uptake of cobalamin (Cbl) within malignant breast tumors in vivo.

PROCEDURES

Prior to surgery 20 female patients with clinically suspected breast tumors were intravenously administered 0.25 μg of an In-111 labeled 5-deoxyadenosylcobalamin (AC) analog ([¹¹¹In]AC) and sequentially imaged with whole-body planar (WBP) and single-photon emission computed tomography (SPECT) between 2-5 h and 20-24 h post-injection (P.I.). The tumor to background (T/B) ratio for [¹¹¹In]AC in breast tumors at 2-5 h was correlated to its expression of estrogen (ER), progesterone (PR), and human epidermal growth factor 2 (HER2) receptors. Subsequent pulse chase (PC) experiments in nude mice burdened with the MDA-MB-231 triple-negative (TN) breast tumor xenograft measured the effect that pulses of AC or dexamethasone (DEX) had on [¹¹¹In]AC uptake in both normal murine tissue and the TN breast tumor.

RESULTS

The mean [¹¹¹In]AC T/B ratio of the patients' 18 resected tumors was 5.8. Comparing ER- and PR-positive tumors (n = 11) to TN and HER2-positive tumors (n = 7), the mean [¹¹¹In]AC T/B ratios at 2-5 h P.I. were 3.2 (range 1.8-5.6) and 10.4 (range 3.3-22.5), respectively. Pulses of 2.0 μg of AC at 2, 8, or 24 h; or 40.0 μg of DEX at 24 h prior to injecting 0.5 μg of [¹¹¹In]AC, increased mean tracer uptake in the MDA-MB-231 tumors by 26.4, 71.5, 92.6, and 49.1 %, respectively. Only the 2- and 24-h PC intervals concomitantly suppressed [¹¹¹In]AC uptake in normal murine tissue while enhancing [¹¹¹In]AC uptake in MDA-MB-231 tumors.

CONCLUSION

The uptake of Cbl within malignant breast tumors can be imaged clinically. Cbl uptake is greatest in TN and HER2-positive breast tumors. A solitary bolus of AC or DEX increases the [¹¹¹In]AC uptake within a breast tumor in vivo. Investigating the cytogenetic mechanisms controlling the endocytosis of Cbl in malignant breast tumors is warranted.

Redox-Related Epigenetic Mechanisms in Glioblastoma: Nuclear Factor (Erythroid-Derived 2)-Like 2, Cobalamin, and Dopamine Receptor Subtype 4

Glioblastoma is an exceptionally difficult cancer to treat. Cancer is universally marked by epigenetic changes, which play key roles in sustaining a malignant phenotype, in addition to disease progression and patient survival. Studies have shown strong links between the cellular redox state and epigenetics. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a redox-sensitive transcription factor that upregulates endogenous antioxidant production, and is aberrantly expressed in many cancers, including glioblastoma. Methylation of DNA and histones provides a mode of epigenetic regulation, and cobalamin-dependent reactions link the redox state to methylation. Antagonists of dopamine receptor subtype 4 (D₄ receptor) were recently shown to restrict glioblastoma stem cell growth by downregulating trophic signaling, resulting in inhibition of functional autophagy. In addition to stimulating glioblastoma stem cell growth, D₄ receptors have the unique ability to catalyze cobalamin-dependent phospholipid methylation. Therefore, D₄ receptors represent an important node in a molecular reflex pathway involving Nrf2 and cobalamin, operating in conjunction with redox status and methyl group donor availability. In this article, we describe the redox-related effects of Nrf2, cobalamin metabolism, and the D₄ receptor on the regulation of the epigenetic state in glioblastoma.

Cell Type-Specific Modulation of Cobalamin Uptake by Bovine Serum

Tracking cellular ⁵⁷Co-labelled cobalamin (⁵⁷Co-Cbl) uptake is a well-established method for studying Cbl homeostasis. Previous studies established that bovine serum is not generally permissive for cellular Cbl uptake when used as a supplement in cell culture medium, whereas supplementation with human serum promotes cellular Cbl uptake. The underlying reasons for these differences are not fully defined. In the current study we address this question. We extend earlier observations by showing that fetal calf serum inhibits cellular ⁵⁷Co-Cbl uptake by HT1080 cells (a fibrosarcoma-derived fibroblast cell line). Furthermore, we discovered that a simple heat-treatment protocol (95°C for 10 min) ameliorates this inhibitory activity for HT1080 cell ⁵⁷Co-Cbl uptake. We provide evidence that the very high level of haptocorrin in bovine serum (as compared to human serum) is responsible for this inhibitory activity. We suggest that bovine haptocorrin competes with cell-derived transcobalamin for Cbl binding, and that cellular Cbl uptake may be minimised in the presence of large amounts of bovine haptocorrin that are present under routine in vitro cell culture conditions. In experiments conducted with AG01518 cells (a neonatal foreskin-derived fibroblast cell line), overall cellular ⁵⁷Co-Cbl uptake was 86% lower than for HT1080 cells, cellular TC production was below levels detectable by western blotting, and heat treatment of fetal calf serum resulted in only a modest increase in cellular ⁵⁷Co-Cbl uptake. We recommend a careful assessment of cell culture protocols should be conducted in order to determine the potential benefits that heat-treated bovine serum may provide for in vitro studies of mammalian cell lines.