The immune-checkpoint HLA-G/ILT4 is involved in the regulation of VEGF expression in clear cell renal cell carcinoma

Background

Clear cell renal cell carcinoma (ccRCC), the most aggressive renal cancer, is characterized by early lymph node metastases and bad prognosis. Most therapies targeting advanced or metastatic ccRCC are based, as first-line treatment, on the administration of the vascular endothelial growth factor (VEGF) neutralizing antibody termed Bevacizumab. Despite proven benefits, the expected results were not obtained for the majority of patients. The possibility that an intricate interplay between angiogenesis and immune-checkpoints might exist lead us to evaluate tumor angiogenesis, by means of VEGF expression together with the immune checkpoint HLA-G/ILT4.

Methods

Tumor specimens were obtained from patients from two separate cohorts: One from “Evita Pueblo” Hospital from Berazategui, (Buenos Aires, Argentina) and the second includes patients surgically operated at the Urology Department of Saint-Louis Hospital (Paris, France) with a confirmed ccRCC diagnosis. Immunohistochemistry was performed with specific antibodies directed against HLA-G, VEGF-A, VEGF-C, D240, CD34, ILT4 and Ca-IX. In addition, gene expression levels were measured in a cell line derived from a ccRCC patient by semi-quantitative RT-PCR.

Results

Our results show that the highly vascularized tumors of ccRCC patients express high levels of VEGF and the immune-checkpoint HLA-G. In addition, ILT4, one of the HLA-G receptors, was detected on macrophages surrounding tumor cells, suggesting the generation of an immune-tolerant microenvironment that might favor tumorigenesis. Notably, RT-qPCR analysis provided the first evidence on the transcriptional relationship between HLA-G/ILT4 and the VEGF family. Namely, in the presence of HLA-G or ILT4, the levels of VEGF-A are diminished whereas those of VEGF-C are increased.

Conclusions

In an effort to find new therapeutic molecules and fight against metastasis dissemination associated with the poor survival rates of ccRCC patients, these findings provide the rationale for co-targeting angiogenesis and the immune checkpoint HLA-G.

DNA synthesis in periportal and perivenous hepatocytes of intact and hepatectomized young mice

DNA synthesis of hepatocytes in two areas of Intact and Hepatectomized young mice liver along a circadian period was studied. DNA synthesis was significantly different at all analyzed time points in Intact and Hepatectomized animals. Differences between periportal and perivenous hepatocytes were found in hepatectomized animals at 04/42 and 08/46 hr of day/hour post-hepatectomy. DNAs peak in periportal hepatocytes regenerating liver occurs 4 hr earlier than in perivenous hepatocytes, probably reflecting their shorter G1 phase. Besides, daily mean values of regenerating livers were higher than those observed in Intact animals, as a consequence of surgical removal.

Entomofauna of a buried body: study of the exhumation of a human cadaver in Buenos Aires, Argentina

This study focuses on insects and other arthropods sampled on the exhumation of an infant skeleton belonging to 'Prof. Dr. Rómulo Lambre' skeletal collection. The body was buried in soil inside a wooden coffin in a grave 40cm deep, in autumn, and stored in the cemetery deposit after exhumation. Death records were obtained from the cemetery archive. Samples of faunal remains were recovered from wrappings, clothes, bones and soil samples, and were identified at different taxonomic levels depending on the stage of conservation. The dominant taxon was the muscid fly Ophyra aenescens (Wiedemann). The relationships among the identified taxa and the moving of the corpse, from the burial context to the cemetery deposit, are discussed and used to create a hypothetical colonization sequence after death. The application of entomological data to anthropological research can provide valuable information for the interpretation of taphonomic processes and burial contexts.

Evaluation of angiogenesis with the expression of VEGF and CD34 in human non-small cell lung cancer

Angiogenesis is an essential process in the progression of malignant tumors and the most potent angiogenic factor is the vascular endothelial growth factor (VEGF). On the other hand, the CD34 is an endothelial antigen that has been used to highlight the microvasculature vessel density (MVD) as a direct marker of the degree of neoangiogenesis. In the present study we report the VEGF expression and its relationship with MVD, measured by CD34, in two lineages of non-small cell lung cancer (NSCL): low differentiated adenocarcinomas and epidermoid carcinomas, in order to consider the possibility of using the correlation between both antibodies as a prognostic factor. Tumor sections were stained by immunohistochemistry for CD34 and VEGF. The results showed that the mean value of VEGF for adenocarcinoma was significantly higher than the one for epidermoid carcinoma (p < 0.001). However, the mean of MVD did not show significant differences between both types of tumors. The conventional factors taken into consideration (age over 60, sex, and presence of lymph nodes) was not significantly related to the angiogenic factors examined. In conclusion, we could affirm that CD34 is a better prognostic marker of neoangiogenesis in NSCLC, because both types of tumors have the same clinical prognosis, and so we expected the same behaviour from both markers.

Chronobiology of the proliferative events related to angiogenesis in mice liver regeneration after partial hepatectomy

In liver regeneration the formation of new capillary blood vessels is a fundamental requirement for cellular proliferation. Vascular endothelial growth factor (VEGF) is involved in the events of angiogenesis, the mRNA of which is expressed in both hepatocytes and non-parenchymal cells. In this experimental design we try to establish if during liver regeneration in mouse, the expression of VEGF is produced before or after the hepatocytes proliferation. C3H/S adult male mice were divided in three groups in order to study: VEGF expression; S-phase index (SI); and mitotic activity (MA) of hepatocytes. The results that were analyzed by ANOVA, show that VEGF expression starts to increase 26 h after PH with a peak at 28 h. Furthermore, the DNA synthesis (DNAs) reaches maximal level 42 h after pH, meanwhile the MA of the hepatocytes shows an increase 8h after the DNAs peak. In conclusion, it could be argued that the chronobiology of the events related to liver regeneration in mice started with a release of VEGF by the hepatocytes, followed by its DNAs and mitosis.

Effect of normal and tumor factors on different phases of cell populations cycle

In the present experiments we studied the effect of extracts from intact liver (LE), ES2 tumor extract (TE), plasmas from intact mice (PI), and from tumor bearing animals (PT) on different phases of hepatocytes and renocytes cell cycles. C3HS 28-day-old male mice, standardized for periodicity analysis, were injected at 16:00 hours and killed every 4 hours during a circadian cycle at 20:00/04; 00:00/08; 04:00/12; 08:00/16; 12:00/20 and 16:00/24 (time of day/hours post treatment). Colchicine (2 microg/g) was injected 4 hours before killing them. Samples of livers and kidneys were processed for histology and mitotic index determinations. The results were expressed as colchicine arrested metaphases per 1000 nuclei. The TE, LE and PI had a promoting effect on the mitotic activity of hepatocytes during the first 12 hours post treatment. During the subsequent 12 hours, not only these treatments but also the PI had an inhibiting effect on the mitotic activity of the same cell population. Also the TE and the PT had a promoting effect on the mitotic activity of the renocytes during the first 12 hours while the effect of all treatments showed a clear inhibition of the mitotic activity studied during the last 12 hours. Taking into account the time elapsed between the injections and the measurements made in these light-dark synchronized animals, we conclude that the increase in mitotic index observed in those tissues stemmed from a reinitiation of cell-cycle traverse in a subpopulation of G2-arrested, noncycling cells.

G2 restriction point within populations of hepatocytes and tongue keratinocytes in young, growing mice

The authors studied the effect of either extracts from liver (LE) or the malignant tumour ES2 (TE) or plasma from intact mice (PI) or tumour-bearing animals (PT) on the mitotic activity of the hepatocytes and tongue keratinocytes in young, growing C3H/s male mice (28+/-1 days old). Animals standardized for periodicity analysis were injected intraperitoneally with either TE, LE, PI, PT, or saline (S) at 16:00 h with 0.01 ml of sample/g of body weight and were then killed at (time of day/h post-injection) 20:00/04, 00:00/08, and 04:00/12. Colchicine (2 microg/g) was injected 4 h before death. Samples of the liver and tongue from each animal were processed for histology and assessment of mitotic index. The results were expressed as colchicine-arrested metaphases/1000 nuclei. The TE and LE stimulated the mitotic activity of hepatocytes and tongue keratinocytes. Taking into account the time elapsed between the injections and the measurements made in these light-dark synchronized animals, we conclude that the increase in mitotic index observed in those tissues stemmed from a reinitiation of cell-cycle traverse in a subpopulation of G2-arrested, noncycling cells.

An initial characterization of a mitostatic activity for hepatocytes and renocytes in extracts from adult mouse liver

We have previously demonstrated that liver extract, when administered at 16:00 hr, inhibits the mitotic activity of hepatocytes and renocytes at 08:00, 12:00 and 16:00 hr. during the following 2 days. The experiments reported here were designed to achieve an initial characterization of this liver mitostatic activity. For these studies we used 28-days-old male C3HS mice injected with either saline, liver extract (LE), mitochondrial-pellet extract (MPE), or postmitochondrial supernatant (PMS) at a dose of 1.9 mg of protein/g body weight. Colchicine (2 microg/g) was injected 4 hrs. before sacrifice and the number of arrested metaphases within the hepatocyte and renocyte population was estimated. The mice treated with LE were killed at (time of day/hr. post injection) 16/08:00, 20/12:00 and 24/16:00; while those injected with MPE or PMS were sacrificed at 20/12:00. We found that both the LE and the PMS inhibited the mitotic activity of hepatocytes and renocytes, while MPE reduced the mitotic activity of the liver cells without affecting that of the renal population.

Effect of tissue and plasma factors on kidney proliferation

Liver extract, plasma from intact mice, ES2 tumour extract and plasma from tumour bearing mice has an inhibiting effect on the mitotic activity of hepatocytes and duodenal enterocytes. In the present experiments, the effect of these treatments on the mitotic activity of renal tubular cells was studied. C3HS 28 day-old male mice, standardized for periodicity analysis were used. The determination of normal mitotic circadian curve of the renocytes was done. A second batch of mice were injected with 0.01 ml/gr of either liver extract, plasma from intact mice, ES2 tumour extract or plasma from tumour bearing mice, at 16:00 hours and controlled at 08:00, 12:00 and 16:00 hs during 2 consecutive days post treatment. Colchicine (2 micrograms/gr) was injected 4 hours before killing. Kidneys were processed for histology and mitotic index determinations. Results were expressed as colchicine metaphases per 1000 nuclei, and showed that mitotic activity values of treated animals were significantly lower than those of controls. In conclusion, mitotic activity inhibition of renocytes may be due to some non specific plasmatic and/or tissue factors.

Action of plasma and liver extract from adult mice on the mitotic activity of young mouse liver

Inbred C3HS male mice, standardized for periodicity analysis were used. A hundred and seventy 25 +/- 2 days old mice were injected at 16:00 hs with saline, plasma or liver extract from 27 mice 90 days old. Controls were made at 08/16, 12/20, 16/24, 08/40, 12/44, 16/48, 08/64, 12/68 and 16/72 (time of day/time post-injection). The mitotic activity of the hepatocytes and litoral cells were determined. The injection of small doses of extract and plasma inhibits the mitotic activity of hepatocytes during the first and second following days. A compensatory wave appears in the third day. The extract inhibits the mitotic activity of litoral cells in the first day of control only, whereas the plasma inhibits this variable in the second and third day.