Intravasation as a Key Step in Cancer Metastasis.

Intravasation is a key step in cancer metastasis during which tumor cells penetrate the vessel wall and enter circulation, thereby becoming circulating tumor cells and potential metastatic seeds. Understanding the molecular mechanisms of intravasation is critically important for the development of therapeutic strategies to prevent metastasis. In this article, we review current data on the mechanisms of cancer cell intravasation into the blood and lymphatic vessels. The entry of mature thymocytes into the circulation and of dendritic cells into the regional lymph nodes is considered as example of intravasation under physiologically normal conditions. Intravasation in a pathophysiological state is illustrated by the reverse transendothelial migration of leukocytes into the bloodstream from the sites of inflammation mediated by the sphingosine 1-phosphate interaction with its receptors. Intravasation involves both invasion-dependent and independent mechanisms. In particular, mesenchymal and amoeboid cell invasion, as well as neoangiogenesis and vascular remodeling, are discussed to play a significant role in the entry of tumor cells to the circulation. Special attention is given to the contribution of macrophages to the intravasation via the CSF1/EGF (colony stimulating factor 1/epidermal growth factor) paracrine signaling pathway and the TMEM (tumor microenvironment of metastasis)-mediated mechanisms. Other mechanisms including intravasation of tumor cell clusters surrounded by the vessel wall elements, cooperative intravasation (entry of non-invasive tumor cells to the circulation following invasive tumor cells), and intravasation associated with the vasculogenic mimicry (formation of vascular channels by tumor cells) are also discussed. Novel intravasation-specific mechanisms that have not yet been described in the literature are suggested. The importance of targeted therapeutic strategies to prevent cancer intravasation is emphasized.

Different morphological structures of breast tumors demonstrate individual drug resistance gene expression profiles.

AIM: To identify gene expression profiles involved in drug resistance of different morphological structures (tubular, alveolar, solid, trabecular, and discrete) presented in breast cancer. MATERIAL AND METHODS: Ten patients with luminal breast cancer have been included. A laser microdissection-assisted microarrays and qRT-PCR were used to perform whole-transcriptome profiling of different morphological structures, to select differentially expressed drug response genes, and to validate their expression. RESULTS: We found 27 differentially expressed genes (p < 0.05) encoding drug uptake (SLC1A3, SLC23A2, etc.) and efflux (ABCC1, ABCG1, etc.) transporters, drug targets (TOP2A, TYMS, and Tubb3), and proteins that are involved in drug detoxification (NAT1 and ALDH1B1), cell cycle progression (CCND1, AKT1, etc.), apoptosis (CASP3, TXN2, etc.), and DNA repair (BRCA1 and USP11). Each type of structures showed an individual gene expression profile related to resistance and sensitivity to anticancer drugs. However, most of the genes (19/27; p < 0.05) were expressed in alveolar structures. Functional enrichment analysis showed that drug resistance is significantly associated with alveolar structures. Other structures demonstrated the similar number (10-13 out of 27) of expressed genes; however, the spectrum of resistance and sensitivity to different anticancer drugs varied. CONCLUSION: Different morphological structures of breast cancer show individual expression of drug resistance genes.

Effect of small and radical surgical injury on the level of different populations of circulating tumor cells in the blood of breast cancer patients.

Circulating tumor cells (CTCs) constitute a heterogeneous population. Some tumor cells are cancer stem cells (CSCs), while others are in the process of the epithelial-mesenchymal transition (EMT); however, most CTCs are neither stem cells nor in the EMT. This prospective study of 22 patients with nonspecific-type invasive carcinoma of the breast identified different populations of CTCs by flow cytometry in the blood of patients before biopsy, after biopsy and after surgical tumor removal without neoadjuvant chemotherapy. The results showed that minor surgical injury (biopsy) was accompanied by a significant increase in the blood levels of CTCs without signs of the EMT or stemness (Epcam+CD45-CD44-CD24-Ncadh-) and CTCs with signs of stemness and without signs of the EMT (Epcam+CD45-CD44+CD24-Ncadh-). Our results suggest that minor surgical injury to a tumor contributes to the release of CTCs into the bloodstream, including a population of stem cells.

Comprehensive meta-analytical summary on human papillomavirus association with head and neck cancer.

An etiological role of high risk human papillomavirus (HPV) in the development of cervical cancer has been well established. Hence, attention of researchers has been focused on the role of HPV in pathogenesis of other malignancies, such as head and neck cancers. An analysis of epidemiological data on the prevalence of HPV infection among healthy people and patients with precancerous lesions and/or cancer is an important step in understanding the role of HPV in head and neck carcinogenesis. More and more data de-monstrate the impact of HPV infection on disease outcome. HPV-positive patients have been shown to have better responses to radiotherapy and better overall and disease-free survival than HPV-negative patients. This review presents data of the meta-analysis based on a large number of original studies on HPV prevalence in patients with precancerous lesions and in patients with oral, oropharyngeal and laryngeal cancers as well as findings on the impact of HPV infection on survival of these patients.

Invasive and drug resistant expression profile of different morphological structures of breast tumors.

In order to understand invasive/adhesive and drug resistant properties of intratumor morphological heterogeneity of breast cancer, we compared the expression of genes responsible for the cell adhesion and for the drug resistance between distinct morphological structures of breast tumors. Tubular (hollow-like), alveolar (morula-like), trabecular, solid structures/patterns, and discrete (small) groups of tumor cells were isolated from invasive carcinoma of no special type (n=3) and invasive micropapillary carcinoma (n=1) of the breast using laser microdissection. The gene expression of cadherins, catenins, integrins, ABC transporters, GSTP1, and drug targets was analyzed using qRT-PCR. Expression of catenin genes was identified in almost all structures. In contrast, the expression of cadherin and integrin genes significantly varied depending on the morphological variant. Cadherin expression declined in the row: solid - alveolar and trabecular structures - discrete groups of tumor cells. Expression of integrins declined in the row: solid and alveolar - trabecular structures - discrete groups of tumor cells. For drug resistance genes, trabecular structures more often demonstrated activity of genes coding for ABC transporters compared to other morphological variants. These results indicate that intratumoral morphological heterogeneity in breast cancer correlates with expression profile of adhesion and drug resistance genes reflecting different patterns of invasive growth and responsiveness to chemotherapy.

[Apoptosis-modulating effects of heat shock proteins: the influence of Hsp27 chaperone on TBA Bcl-2 family proteins in Jurkat cell line].

The in vitro phosphorylated and non-phosphorylated Hsp27 forms concentrations and Bcl-2 proteins affected by Hsp27 inhibition were studied in Jurkat-line tumor cells and healthy donor mononuclear lymphocytes by Western blotting technique. The Hsp27 inhibition causes the increase of intracellular Bax protein concentration and the decrease of Bcl-2 level leading to an increase of apoptotic changes in Jurkat line cells.

Effects of HSP27 chaperone on THP-1 tumor cell apoptosis.

The role of Hsp27 (heat shock protein 27) chaperone in regulation of THP-1 tumor cell apoptosis was studied. Realization of tumor cell apoptosis under conditions of in vitro culturing with Hsp27 specific inhibitor (KRIBB3) was evaluated by fluorescent microscopy with FITC-labeled annexin V and propidium iodide. Measurements of Bcl-2 family proteins (Bcl-2, Bax, Bad) in tumor cells incubated with Hsp27 inhibitor were carried out by Western blotting. Chaperone Hsp27 acted as apoptosis inhibitor in THP-1 tumor cells modulating the proportion of antiapoptotic (Bcl-2) and proapoptotic (Bax and Bad) proteins.

[Heat shock protein 90--modulator of TNFalpha-induced apoptosis of Jurkat tumor cells].

rTNFalpha-induced programmed death of Jurkat tumor cells cultured with 17-AAG, a selective inhibitor of heat shock protein (Hsp90), was studied by fluorescent microscopy with the use of FITC-labeled annexin V and propidium iodide. Caspase-3 and -8 activities were determined by spectrophotometry using a caspase- 3 and -8 colorimetric assay kit. It was shown that inhibition of Hsp90 leads to activation of Jurkat cell apoptosis while Hsp90 itself suppresses this process. 17-AAG enhances rTNFa-induced apoptosis of tumor cells.

Role of hydrogen sulfide in the regulation of cell apoptosis.

We studied the effect of a gas transmitter hydrogen sulfide (H(2)S) on the realization of apoptosis in Jurkat cells and mononuclear leukocytes from healthy donors. Treatment with H(2)S donor NaHS was accompanied by a dose-dependent intensification of cell death via apoptosis and necrosis. T-cell leukemia cells were more sensitive to H2S than mononuclear leukocytes from healthy donors. H(2)S-induced cell apoptosis was accompanied by activation of caspase-3 and caspase-9.

The role of heat shock protein 90 in the regulation of tumor cell apoptosis.

Programmed death of Jurkat tumor cells was studied under conditions of culturing with 17-AAG selective inhibitor of heat shock protein with a molecular weight of 90 kDa and etoposide. Apoptosis realization was evaluated by fluorescent microscopy with FITC-labeled annexin V and propidium iodide. Activity of caspase-3 was evaluated spectrophotometrically. Inhibition of heat shock protein with a molecular weight of 90 kDa activated the apoptotic program in Jurkat tumor cells and etoposide-induced apoptosis. The heat shock protein with a molecular weight of 90 kDa acted as apoptosis inhibitor in tumor cells.

[Mitogenactivated protein kinases JNK and p38 as redox-dependent molecular targets correction of programmed cell death disturbances in oxidative stress condition].

The article summarizes information from recent literature and results of the author's own investigations concerning role of mitogenactivated protein kinases JNK and p38 in disturbances of programmed cell death regulation in oxidative stress condition.

[The role of p53 and NF-kappaB transcription factors in redox-dependent dysregulation of mononuclear leukocyte apoptosis].

The aim of this work was to study programmed death of blood mononuclear leukocytes taken from healthy donors and patients with acute inflammatory diseases (acute appendicitis, community-acquired pneumonia). Cellular p53 and NF-kappaB transcription factors were detected by western blotting. Active form of NF-kappaB was shown to appear in mononuclear leukocytes undergoing oxidative stress in experiment and during acute inflammation, p53 was found only under oxidative stress conditions in vitro. Despite enhanced expression of target gene mRNA of these transcription factors in oxidative stress (proapoptotic protein Bax and antiapoptotic protein Bcl-XL), the resulting vector of p53 and NF-kappaB activation is stimulation of cell's apoptotic reaction.

[The role of redox-dependent signal systems in the regulation of apoptosis under oxidative stress condition].

Programmed death of peripheral blood mononuclear cells from donors with acute inflammatory diseases (an acute appendicitis, a community-acquired pneumonia) was investigated under condition of oxidative stress in vitro and under effect of selective inhibitors of MAP-kinases JNK and p38. Levels of active and inactive forms of MAP-kinases, and factors of transcription were determined by immunoblotting (western blot analysis). The increase in the activity of apoptosis under condition of oxidative stress in vivo and during the acute inflammatory diseases is associated with the increase in the level of reactive oxygen species (ROS) in the cells. The action of inhibitors of MAP-kinases JNK (SP600125) and p38 (ML3403) in vitro under condition of oxidative stress prevents increase in the quantity of annexin-positive mononuclear leucocytes that testifies to involving JNK and p38 MAP-kinases in apoptosis deregulation oxidative mechanisms. The appearance of NF-kappaB in the mononuclear leucocytes under condition of oxidative stress during the acute inflammatory diseases and at the experiment was shown; p53 was registered only under condition of oxidative stress in vitro. The effect of p53 and NF-kappaB results in the increase in the quantity of apoptosis annexin-positive mononuclear leucocytes that testify to inoperativeness of antiapoptotic regulation NF-kappaB.

[Redox-dependent regulation of apoptosis as a function of intracellular reactive oxygen species in oxidative stress].

Programmed cell death of mononuclear cells in conditions of oxidative stress in vitro and selective inhibitors of MAP-kinases JNK, p38 were investigated. Levels of active and inactive forms of MAP-kinases, factors of transcription P53, NF-kB and proteins-regulators of apoptosis Bcl-X(L), Bad, Bcl-2 were determined by immunoblotting (Western blotting). The increasing of number of annexin-plus mononuclears/lymphocytes in the culture associated with enhance of the level of intracellular reactive oxygen species was shown. The treatment of selective inhibitors JNK SP600125 and p38 ML3403 in vitro prevents peroxide-induced appearance of P53 and NF-kB in blood mononuclear cells, associated with increasing of their apoptotic activity. The disturbance of the balance of pro- and antiapoptotic proteins of Bcl-2, family (the increase of the Bax level without changes of Bcl-X(L) and Bcl-2) leads to the growth of apoptosis process of mononuclear leucocytes activity in oxidative stress conditions.