[Membrane type 1 matrix metalloproteinase (MT1-MMP) and the regulators of its activity as invasive factors in squamous cell cervical carcinomas].

Membrane type 1 matrix metalloproteinase (MT1MMP) is one of matrix metalloproteinases (MMP), which play а key role in tumor invasion and metastasis. The aim of this study was to elucidate the peculiarities of expression of MT1MMP and endogenous regulators of its activity: the activator - furin and the inhibitor - TIMP-2, as invasive factors of squamous cell cervical carcinomas (SCC). The study was carried out using 11 specimens of SCC and 11 specimens of morphologically normal tissue adjacent to the tumor. It was shown that the increase of MT1-MMP and furin expression and low of TIMP-2 expression makes the main contribution to the destructive (invasive) potential of SCC. Moreover, substantial expression of MT1-MMP was registered in the specimens of morphologically normal adjoining to tumor tissue. This expression was found to make an additional contribution to the destructive potential of the cervical tumor.

[Key enzymes of degradation and angiogenesis as a factors of tumor progression in squamous cell carcinoma of the cervix].

A key role in tumor progression play two processes--the destruction and angiogenesis. Matrix metalloproteases (MMPs) play a leading role during tissue degradation. Tissue collagenase--MMP-1 and MT1-MMP hydrolyze fibrillar collagens, which are the basis of connective tissue matrix, and ensure the development of an invasive process. Gelatinase A and B (MMP-2 and MMP-9) hydrolyze collagen type IV, which is the basis of the basal membrane, and facilitate the development of metastasis. Endogenous tissue inhibitors TIMP-1 and TIMP-2 are involved in the regulation of MMP expression and activity. It has been established that MMP-9 release vascular endothelial growth factor (VEGF) associated with the STM--the primary inductor angiogenesis. Angiotensin-converting enzyme (ACE) participates in the induction of VEGF synthesis. ACE--a key enzyme of the renin-angiotensin system, forms angiotensin II, which interactes with the receptor ATIR and induces VEGF synthesis, as well as stimulates endothelial cell proliferation. Our experimental studies devoted to the study of particularity expression of key enzymes of destruction and angiogenesis in squamous cell carcinoma of the cervix (SCC). It was studied: MMP-1, MT1-MMP, MMP-2 and MMP-9 and their endogenous regulators: TIMP-1, TIMP-2, and as well as ACE. Work was performed on clinical specimens containing the tumor tissue, taking into account the presence or absence of metastasis to regional lymph nodes and the specimens of adjacent morphologically normal tissue. It was shown that the increase of MMP-1, MT1-MMP and MMP-9 expression and low of TIMP-1 and TIMP-2 expression makes the main contribution to the destructive (invasive) potential of SCC. The change of MMP-2 expression is not so significant and it is less influenced to the destructive potential. It was shown dramatic increasing of MMP-1 and MMP-9 activity in metastasizing tumor tissue ACE activity in a tumor in most of the samples was higher than the activity in normal tissues. It was established that the expression of key enzymes degradation and angiogenesis occurs not only in tumor but also in normal tissues. Data are important for understanding the mechanisms of tumor progression and have prognostic value and may affect the therapeutic strategy for patients.

[Angiotensin converting enzyme and Alzheimer's disease].

Alzheimer's disease (AD) is an incurable degenerative disease of the central nervous system, leading to dementia. The basis of AD is neurodegenerative process that leads to death of neurons in the cerebral cortex. This neurodegenerative process is associated with the formation of neurofibrillary tangles in the brain and the deposition of senile plaques, the main component of which is a beta-amyloid peptide (Abeta). Risk factors for AD are age, as well as hypertension, atherosclerosis, diabetes and hypercholesterolemia in the pathogenesis of which involved angiotensin converting enzyme (ACE)--key enzyme of the renin-angiotensin (RAS) and kallikrein-kinin (KKS) systems. Recently it was discovered that ACE, along with other metallopeptidases, participates in the metabolism of Abeta, cleaving the bonds at the N-terminal and C-terminal region of the molecule Abeta. The role of the ACE in the degradation processes of Abeta takes an interest. It is associated with the fact that the using of ACE inhibitors is the main therapeutic approach used in the treatment of various forms of hypertension and other cardiovascular diseases. However, until now not been resolved, can be used antihypertensive drugs that inhibit RAS for the treatment or prevention of AD. Currently, there are numerous studies on finding the relationship between RAS and AD.

[ACE inhibitors--activators of kinin receptors].

Angiotensin converting enzyme (ACE) inhibitors are widely used for treatment of cardiovascular diseases. The effects of ACE inhibitors on the human bradykinin receptors were investigated. The mode of action of ACE inhibitors is considered. There is evidence that ACE inhibitors exert effects on the vascular system that cannot be attributed simply to the inhibition of ACE activity and accumulation of locally produced bradykinin. ACE inhibitors augment bradykinin effects on receptors indirectly by inducing cross-talk between ACE and the B2 receptor when enzyme and receptor molecules are sterically close, possibly forming a heterodimer. ACE inhibitors activate B1 receptors directly and independently of ACE via the zink-binding consensus sequence HEXXH, which is present in B1, but not in B2 receptor. Particular structure of B2 and B1 are represented, as well as receptor amino acids coupled with the G-proteins. Activation of kinin receptors by ACE inhibitors leads to clinically beneficial effects of ACE inhibitors.

[Structure and physiological significance of angiotensin converting enzyme domains].

Somatic angiotensin converting enzyme (ACE) consists of two homologous catalytic domains (N- and C-domain), each of which bears an active site exhibiting different biochemical properties. The ACE isoforms consisted of one domain were also detected in mammals. Substantial progress in ACE domain research was achieved during the last years, when crystal their structures were determined. The crystal structures of domains in complex with diverse potent ACE inhibitors provided new insights into structure-based differences of the domain active sites. Physiological functions of ACE are not limited by regulation of the cardiovascular system. Recent evidence suggests that the ACE domains may be also involved into control distinct physiological functions. The C-terminal catalytic domain, playing important role in regulation of blood pressure, catalyzes angiotensin I cleavage in vivo. The N-domain contributes to processing of other bioactive peptides for which it exhibits high affinity. Domain-selective inhibitors able to block selectively either the N- or C-domain of ACE have been developed.

[Study of substrate specificity of a new peptide substrate of endothelin converting enzyme].

The new fluorogenic hexapeptide substrate CMC-Ala-Gly-Gly-Trp-Phe-Arg was used as substrate for endothelin-converting enzyme (ECE), angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP). The specific inhibitors lisinopril (ACE) and thiorphan (NEP) were used for identification of these enzyme activities,

[Angiotensin converting enzyme domain structure and properties].

Angiotensin converting enzyme (ACE) is a key enzyme of the renin-angiotensin and kallikrein-kinin systems responsible for the regulation of blood pressure. Recently the new physiological function of ACE has been revealed: the enzyme hydrolyses in vivo the natural peptide (N-AcSer-Asp-Lys-Pro), a negative regulator of hematopoietic stem cell proliferation. Somatic ACE is a single-chain glycoprotein, which contains two highly homologous domains (N- and C-domains, respectively), possessing a zinc-dependent active site. The domains differ in the rate of substrate hydrolysis, interaction with ACE inhibitors and chloride activation profiles. Specific ACE inhibitors used for treatment of hypertension, inhibit both domains, but their dissociation rates of enzyme-inhibitor complex are different. Selective binding of ACE inhibitors to either N- or C-domain may influence their biological effect during treatment. Different functional significance of these domains may be due to some differences in their thee-dimentional structures. X-ray structure of testicular ACE was recently solved and three-dimentional structure of N-domain was modeled. The structural features of domain active sites may be useful for construction of new selective inhibitors.

[Participation of serine proteinases in transforming the high molecular weight (600 kDa) form of angiotensin 1-converting enzyme into the low molecular weight form (190 kDa)]. / Uchastie serinovoi proteinazy v prevrashchenii vysokomolekuliarnoi (600 kDa) formy angiotenzin 1-prevrashchaiushchego fermenta v nizkomolekuliarnuiu (190 kDa).

A high molecular form of angiotensin-converting enzyme with mol mass about 600 kDa was found simultaneously with the well-known low molecular enzyme form of 190 kDa after fractionation of freshly prepared extracts from bovine kidney cortex and lung tissues by means of ammonium sulfate or gel filtration on Sephadex G-200. The rate of substrate hydrolysis was adequately Cl'-dependent for both these enzyme forms and specific inhibitors nonapeptide SQ 20881 and pentapeptide SQ 20475 inhibited similarly their activity. The enzyme high molecular form transformed into its low molecular derivative after storage, in freezing-thawing and ultrafiltration. Aprotinin, the inhibitor of serine proteinases, inhibited this kind of transformation. Stable form of the high molecular angiotensin-converting enzyme, which did not transform into its low molecular derivative, was obtained after treatment with agarose-immobilized aprotinin. Endogenous serine proteinases, which may regulate the angiotensin-converting activity in vivo, appears to be responsible for the enzyme transformation into its low molecular derivative.

[Inhibition of the angiotensin-converting enzyme from bovine kidney by organophosphorus analogs of amino acids]. / Ingibirovanie angiotenzinprevrashchaiushchego fermenta iz pochek byka fosfororganicheskimo analogami aminokislot.

Reactions of amino acid phosphoorganic derivatives with angiotensin-converting enzyme (dipeptidyl carboxypeptidase) were studied. Substitution of the amino acid carboxyl group by HS- or P(O) (OH)2-groups did not cause the enzyme considerable inhibition. The enzymatic activity was inhibited by 20-50% in presence of 1 X 10(-3) M Asp, Met and Cys phosphoorganic derivatives. These amino acid derivatives may be used as potential antihypertensive drugs because of their metabolic stability and inhibitory action on the enzyme.

[Induction of blood plasma carboxycathepsin (angiotensin I-converting enzyme) in normo- and hypertensive rats in response to a single administration of captopril]. / Induktsiia karboksikatepsina (angiotenzin-I-prevrashchaiushchego fermenta) plazmy krovi normo- i gipertenzivnykh krys v otvet na odnokratnoe vvedenie kaptoprila.

The experiments were carried out to elucidate the effect of carboxycathepsin (CC) activity inhibition by a specific inhibitor--captopril--on plasma enzyme concentration in normotensive rats and rats with renovascular hypertension. A single oral administration of captopril (10 mg/kg body weight) produced an increase in CC concentration in both hypertensive and sodium-depleted normotensive rats with a parallel decrease in arterial pressure, but had no effect on sodium-repleted normotensive rats. It is suggested that the increase in plasma CC concentration is a compensatory response to the inhibition of CC activity by captopril; it is also possible that the increase observed reflects the state of renin-angiotensin system.