Activity of Potassium Channels in CD8+ T Lymphocytes: Diagnostic and Prognostic Biomarker in Ovarian Cancer?

CD8+ T cells play a role in the suppression of tumor growth and immunotherapy. Ion channels control the Ca2+-dependent function of CD8+ lymphocytes such as cytokine/granzyme production and tumor killing. Kv1.3 and KCa3.1 K+ channels stabilize the negative membrane potential of T cells to maintain Ca2+ influx through CRAC channels. We assessed the expression of Kv1.3, KCa3.1 and CRAC in CD8+ cells from ovarian cancer (OC) patients (n = 7). We found that the expression level of Kv1.3 was higher in patients with malignant tumors than in control or benign tumor groups while the KCa3.1 activity was lower in the malignant tumor group as compared to the others. We demonstrated that the Ca2+ response in malignant tumor patients is higher compared to control groups. We propose that altered Kv1.3 and KCa3.1 expression in CD8+ cells in OC could be a reporter and may serve as a biomarker in diagnostics and that increased Ca2+ response through CRAC may contribute to the impaired CD8+ function.

Heterogeneous Maturation of Arterio-Venous Fistulas and Loop-Shaped Venous Interposition Grafts: A Histological and 3D Flow Simulation Comparison.

Vascular graft maturation is associated with blood flow characteristics, such as velocity, pressure, vorticity, and wall shear stress (WSS). Many studies examined these factors separately. We aimed to examine the remodeling of arterio-venous fistulas (AVFs) and loop-shaped venous interposition grafts, together with 3D flow simulation. Thirty male Wistar rats were randomly and equally divided into sham-operated, AVF, and loop-shaped venous graft (Loop) groups, using the femoral and superficial inferior epigastric vessels for anastomoses. Five weeks after surgery, the vessels were removed for histological evaluation, or plastic castings were made and scanned for 3D flow simulation. Remodeling of AVF and looped grafts was complete in 5 weeks. Histology showed heterogeneous morphology depending on the distribution of intraluminal pressure and WSS. In the Loop group, an asymmetrical WSS distribution coincided with the intima hyperplasia spots. The tunica media was enlarged only when both pressure and WSS were high. The 3D flow simulation correlated with the histological findings, identifying "hotspots" for intimal hyperplasia formation, suggesting a predictive value. These observations can be useful for microvascular research and for quality control in microsurgical training.

[The role of carbonic anhydrase IX in the progression of malignant tumors - a potential therapeutic target?] / A szénsavanhidráz IX szerepe a malignus daganatok progressziójában ­ lehetséges terápiás célpont?

Insufficient tissue perfusion in malignancies results in hypoxic areas, favoring neoplastic progression. Tumor cells under hypoxia undergo an adaptive program by activating alternative metabolic pathways, which is regulated by hypoxia inducible factor-1 (HIF1) in order to overcome microenvironmental changes. The expression of carbonic anhydrase IX (CAIX) is a prominent protective mechanism against intracellular acidosis occurring in cancer cells suffering from hypoxia. Due to the activity of CAIX, the restored intracellular pH (pHi) supports tumor cell proliferation and migration, while the compensatory extracellular acidosis contributes to immunoprotection and to chemo- and radioresistance. In vitro and animal model experiments showed that the chemotherapeutic efficiency could be significantly improved by the selective inhibition of CAIX, thus, its adjuvant therapeutic potential is under active investigation.

In Vivo Molecular Imaging of the Efficacy of Aminopeptidase N (APN/CD13) Receptor Inhibitor Treatment on Experimental Tumors Using 68Ga-NODAGA-c(NGR) Peptide.

INTRODUCTION: The aminopeptidase N (APN/CD13) receptor plays an important role in the neoangiogenic process and metastatic tumor cell invasion. Clinical and preclinical studies reported that bestatin and actinonin are cytotoxic to APN/CD13-positive tumors and metastases due to their APN/CD13-specific inhibitor properties. Our previous studies have already shown that 68Ga-labeled NGR peptides bind specifically to APN/CD13 expressing tumor cells. The APN/CD13 specificity of 68Ga-NGR radiopharmaceuticals enables the following of the efficacy of antiangiogenic therapy with APN/CD13-specific inhibitors using positron emission tomography (PET). The aim of this in vivo study was to assess the antitumor effect of bestatin and actinonin treatment in subcutaneous transplanted HT1080 and B16-F10 tumor-bearing animal models using 68Ga-NODAGA-c(NGR). MATERIALS AND METHODS: Three days after the inoculation of HT1080 and B16-F10 cells, mice were treated with intraperitoneal injection of bestatin (15 mg/kg) or actinonin (5 mg/kg) for 7 days. On the 5th and 10th day, in vivo PET scans and ex vivo biodistribution studies were performed 90 min after intravenous injection of 5.5 ± 0.2 MBq68Ga-NODAGA-c(NGR). RESULTS: Control-untreated HT1080 and B16-F10 tumors were clearly visualized by the APN/CD13-specific 68Ga-NODAGA-c(NGR) radiopharmaceutical. The western blot analysis also confirmed the strong APN/CD13 positivity in the investigated tumors. We found significantly (p ≤ 0.05) lower radiopharmaceutical uptake after bestatin treatment and higher radiotracer accumulation in the actinonin-treated HT1080 tumors. In contrast, significantly lower (p ≤ 0.01) 68Ga-NODAGA-c(NGR) accumulation was observed in both bestatin- and actinonin-treated B16-F10 melanoma tumors compared to the untreated-control tumors. Bestatin inhibited tumor growth and 68Ga-NODAGA-c(NGR) uptake in both tumor models. CONCLUSION: The bestatin treatment is suitable for suppressing the neoangiogenic process and APN/CD13 expression of experimental HT1080 and B16-F10 tumors; furthermore, 68Ga-NODAGA-c(NGR) is an applicable radiotracer for the in vivo monitoring of the efficacy of the APN/CD13 inhibition-based anticancer therapies.

In Vivo Imaging of Hypoxia and Neoangiogenesis in Experimental Syngeneic Hepatocellular Carcinoma Tumor Model Using Positron Emission Tomography.

INTRODUCTION: Hypoxia-induced α ν ß 3 integrin and aminopeptidase N (APN/CD13) receptor expression play an important role in tumor neoangiogenesis. APN/CD13-specific 68Ga-NOTA-c(NGR), α ν ß 3 integrin-specific 68Ga-NODAGA-[c(RGD)]2, and hypoxia-specific 68Ga-DOTA-nitroimidazole enable the in vivo detection of the neoangiogenic process and the hypoxic regions in the tumor mass using positron emission tomography (PET) imaging. The aim of this study was to evaluate whether 68Ga-NOTA-c(NGR) and 68Ga-DOTA-nitroimidazole allow the in vivo noninvasive detection of the temporal changes of APN/CD13 expression and hypoxia in experimental He/De tumors using positron emission tomography. MATERIALS AND METHODS: 5 × 106 hepatocellular carcinoma (He/De) cells were used for the induction of a subcutaneous tumor model in Fischer-344 rats. He/De tumor-bearing animals were anaesthetized, and 90 min after intravenous injection of 10.2 ± 1.1 MBq 68Ga-NOTA-c(NGR) or 68Ga-NODAGA-[c(RGD)]2 (as angiogenesis tracers) or 68Ga-DOTA-nitroimidazole (for hypoxia imaging), whole-body PET/MRI scans were performed. RESULTS: Hypoxic regions and angiogenic markers (α v ß 3 integrin and APN/CD13) were determined using 68Ga-NOTA-c(NGR), 68Ga-DOTA-nitroimidazole, and 68Ga-NODAGA-[c(RGD)]2 in subcutaneously growing He/De tumors in rats. 68Ga-NOTA-c(NGR) showed the strong APN/CD13 positivity of He/De tumors in vivo, by which observation was confirmed by western blot analysis. By the qualitative analysis of PET images, heterogenous accumulation was found inside He/De tumors using all radiotracers. Significantly (p ≤ 0.01) higher SUVmean and SUVmax values were found in the radiotracer avid regions of the tumors than those of the nonavid areas using hypoxia and angiogenesis-specific radiopharmaceuticals. Furthermore, a strong correlation was found between the presence of angiogenic markers, the appearance of hypoxic regions, and the tumor volume using noninvasive in vivo PET imaging. CONCLUSION: 68Ga-DOTA-nitroimidazole and 68Ga-NOTA-c(NGR) are suitable diagnostic radiotracers for the detection of the temporal changes of hypoxic areas and neoangiogenic molecule (CD13) expression, which vary during tumor growth in a hepatocellular carcinoma model.

Carbonic Anhydrase Inhibitor Acetazolamide Enhances CHOP Treatment Response and Stimulates Effector T-Cell Infiltration in A20/BalbC Murine B-Cell Lymphoma.

The inhibition of cancer-related carbonic anhydrase (CA) activity is a promising way to intensify anti-tumor responses. In vitro data suggest improved efficacy of cytotoxic drugs in combination with CA-inhibitors in several cancer types. Despite accumulating data on CA-expression, experimental or clinical studies towards B-cell lymphoma therapy are missing. We therefore decided to test the effect of the CA-inhibitor acetazolamide (AA) on the conventional CHOP treatment regimen using the A20/BalbC in vivo syngeneic mouse lymphoma model. Tumor growth characteristics, 18F-MISO-PET activity, histomorphology, cell proliferation, and T-cell immune infiltrate were determined following single or multiple dose combinations. All results point to a significant increase in the anti-tumor effect of CHOP+AA combinations compared with the untreated controls or with the single CHOP or AA treatments. CD3+ and CD8+ T-cell immune infiltrate increased 3-4 times following CHOP+AA combination compared with the classical CHOP protocol. In conclusion, CA-inhibitor AA seems to act synergistically with the anti-tumor treatment CHOP in aggressive lymphoma. Further to a cytotoxic effect, AA and other more selective blockers potentially support tumor-associated immune responses through the modification of the microenvironment. Therefore, CA-inhibitors are promising candidates as adjuvants in support of specific immunotherapies in lymphoma and other malignancies.

Sustain, Adapt, and Overcome-Hypoxia Associated Changes in the Progression of Lymphatic Neoplasia.

Irregular perfusion and related tissue hypoxia is a common feature of solid tumors the role of which in the survival and progression cancer has been gradually recognized. Adaptation and selection mechanisms in hypoxic areas in solid tumors are regulated by Hypoxia Inducible transcriptional factor 1 (HIF1) and other hypoxia mediators and are associated with aggressive clinical behavior in a large spectrum of malignancies. Aggressive forms of lymphatic neoplasias present with solid tumor-like features, also including rapid cell growth, necrosis and angiogenesis, the clinical potential of which is still underestimated. While the role of regional hypoxia in normal B-cell maturation and malignant transformation is becoming evident, the impact of tissue hypoxia on their behavior is not well-understood. Compared to some of the common solid cancer types data for some of the key regulators, such as HIF1 and HIF2, and for their downstream effectors are available in a limited fashion. In the current review we aim to overview the physiological aspects of major hypoxia pathways during B-cell maturation and adaptation-related changes reported in lymphatic neoplasia covering important targets, such as carbonic anhydrases IX and XII (CAIX, CAXII), glucose transporter 1 (GLUT-1) and vascular endothelial growth factor (VEGF). In conclusion, experimental and clinical results direct to important but currently unexploited role of hypoxia-driven resistance mechanisms especially in aggressive forms of B-cell neoplasia.

Quantitative Analysis of Carbonic Anhydrase IX Uncovers Hypoxia-Related Functional Differences in Classical Hodgkin Lymphoma Subtypes.

Upregulation of carbonic anhydrase IX (CAIX) was found to be associated with unfavorable prognosis and resistance to treatment in a broad spectrum of malignancies, recently also in classical Hodgkin's lymphoma (cHL). As demonstrated, variable CAIX expression in a significant number of cHL cases was associated with poor treatment response. The current study focused on the quantification CAIX immunopositivity and its relative expression compared to the total CD30+ neoplastic pool using digital image analysis. One hundred and one lymph node samples featuring cHL histology were analyzed for both CD30 and CAIX by immunohistochemistry. Whole histological slides were scanned and immunopositivity was determined as the histoscore (H-score) using the DensitoQuant software module (3DHistech Kft., Budapest, Hungary). CAIX positivity was observed in the HRS-cells of 56/101 cases (55.44%) and frequently observed in the proximity of necrotic foci. CAIX H-scores were highly variable (range: 2.16-90.36, mean 18.7 ± 18.8). Individual CAIX values were independent of the much higher CD30 values (range 3.46-151.3, mean 52.37 ± 30.74). The CAIX/CD30 index proved to be the highest in the aggressive lymphocyte-depleted (LD) subtype (CAIX/CD30: 0.876). The CAIX expression and the CAIX/CD30 relative index can be precisely determined by image analysis, and values reflect the extent of a tumor mass undergoing hypoxic-stress-related adaptation in the most aggressive forms of cHL.

Hypoxia-related carbonic anhydrase IX expression is associated with unfavourable response to first-line therapy in classical Hodgkin's lymphoma.

AIMS: The present study evaluates the impact of hypoxia-related carbonic anhydrase IX and XII isoenzyme expression as a basic adaptive mechanism to neutralise intracellular acidosis in classical Hodgkin's lymphoma (cHL). METHODS AND RESULTS: Eighty-one primary biopsies and 15 relapsed tissue samples diagnosed with cHL were analysed for necrosis, CAIX and CAXII expression and cell proliferation to compare hypoxia-related histological and functional data with survival characteristics. Variable, but highly selective cell membrane CAIX expression could be demonstrated in Hodgkin-Reed-Sternberg (HRS) cells in 39 of 81 samples (48.1%), while virtually no staining presented in their microenvironment. In contrast, CAXII expression in HRS cells could be demonstrated in only 18 of 77 samples (23.4%), with significant stromal positivity (50 of 77, 64.9%). The CAIX+ positive phenotype was strongly associated with lymphocyte depletion (four of four, 100%) and nodular sclerosis (29 of 51, 56.9%) subtypes. CAIX/Ki-67 dual immunohistochemistry demonstrated suppressed cell proliferation in CAIX+ positive compared to CAIX- negative HRS cells (P < 0.001). Seventy-two months' progression-free survival (PFS) was significantly lower for the CAIX positive group (0.192) compared with the CAIX negative group (0.771) (P < 0.001), while the overall survival (OS) did not differ (P = 0.097). CONCLUSION: Hypoxic stress-related adaptation - highlighted by CAIX expression - results in cellular quiescence in HRS cells, potentially contributing to the short-term failure of the standard chemotherapy in cHL.