EMMPRIN is an emerging protein capable of regulating cancer hallmarks

EMMPRIN, also known as Basigin or CD147, is a transmembrane glycoprotein member of the immunoglobulin superfamily. It is expressed basally in cells that regulate physiological processes of the cardiovascular, nervous, and immune systems. However, EMMPRIN is also capable of interacting with different proteins, like VEGFR, SMAD4, Integrin, MCT, CyPA, GLUT1, CAIV, Annexin II, Cav-1, CAML, etc., and regulating signaling pathways that stimulate the cell processes of proliferation, apoptosis, metabolism, adhesion, invasion, migration, metastasis, tumor immune response, and angiogenesis processes, which favors the development of different types of cancer. EMMPRIN is the first protein reported that favors cancer development due to its ability to interact with extracellular, intracellular, and membrane proteins. In conclusion, EMMPRIN regulates several proteins associated with the development of tumor processes. Therefore, blocking the expression of EMMPRIN can be a therapeutic target, and the analysis of its expression can be used as an important biomarker in cancer.

Long non-coding RNAs as new players in cervical carcinogenesis: an update

Cervical cancer (CC) is the fourth most common cancer in women worldwide. Therefore, it is very important to understand cervical carcinogenesis, as well as the molecular mechanisms and signaling pathways involved in this process, in order to develop new strategies that contribute to diagnosis, prognosis and treatment of cervical cancer. Infection by high risk-human papillomavirus (HR-HPV) is a key event in cervical carcinogenesis, as well as, other factors, such as sociodemographics, lifestyle, sexual behavior, etc. In recent years, it has been shown that long non-coding RNA (lncRNA) are involved in CC and can be classified into tumor promoters or suppressors. Currently, several studies have analyzed the molecular mechanisms of some lncRNA in CC that might be acting, such as 1) competing endogenous RNAs (ceRNAs), 2) activators of signaling pathways, and 3) transcriptional regulators of genes. In this review, we summarized the more recent information on lncRNA and their role in the development of CC.

Ethnic variation of the C677T and A1298C polymorphisms in the methylenetetrahydrofolate-reductase (MTHFR) gene in southwestern Mexico

In this study, we examined the distribution of genotype and allele frequencies of the C677T and A1298C polymorphisms in the methylenetetrahydrofolate-reductase gene (MTHFR) in two ethnic groups in the State of Guerrero, Mexico, which were compared with those of the Mestizo population of the region. A comparative study was conducted on 455 women from two ethnic groups and a group of Mestizo women of the State of Guerrero, Mexico: 135 Nahuas, 124 Mixtecas, and 196 Mestizas. Genotyping of both polymorphisms were performed by using polymerase chain reaction-restriction fragment length polymorphism methods. We found that the 677TT genotype was more frequent in Nahua and Mixteca women compared to Mestiza women (P = 0.008), and the most prevalent genotype in both ethnic groups was the 1298AA genotype (P < 0.001). We also compared the 677T allele frequency obtained from the groups studied with the frequencies reported in other ethnic groups of Mexico (Huichol, Tarahumara, and Purepecha). There were significant differences between the three ethnic groups compared to Nahuas (Huicholes, P = 0.004; Tarahumaras, P < 0.001; Purepechas, P = 0.042). Our results indicated significant differences in the frequencies of the C677T and A1298C polymorphisms between the two ethnic groups and the Mestizo population of the State of Guerrero. In addition, we found strong differences with other ethnic groups in Mexico. These results could be useful for future studies investigating diseases related to folate metabolism, and could help the government to design specific nutrition programs for different ethnic groups.

The integration of HR-HPV increases the expression of cyclins A and E in cytologies with and without low-grade lesions

Background:

Cyclin-A and cyclin-E are regulators of G1–S phase of normal cell cycle. Integration of human papilloma virus high-risk (HR-HPV) could alter this mechanism, and its overexpression has been associated with poor prognosis in cervical cancer.

Aim:

To determine the expression of cyclin-A and cyclin-E, types of HR-HPV and physical state of DNA in cytologies with the diagnosis of low-grade squamous intraepithelial lesion (LSIL).

Materials and Methods:

115 cytological specimens in liquid base (liquid-PREP^™) were analyzed. 25 specimens were with no signs of SIL (NSIL) and without HPV; 30 with NSIL with low-risk HPV (LR-HPV); 30 with NSIL with HR-HPV; and 30 with both LSIL and HR-HPV. The expression of cyclins was evaluated by immunocytochemistry; and the detection of viral DNA was done by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLPs) for genotyping or sequencing of HPV. The physical state of HPV was evaluated by in situ hybridization with amplification with tyramide.

Results:

In the cytologies NSIL with LR-HPV, the expression of cyclin-A and cyclin-E was found respectively in 23.3% and 33.3% of the specimens. Among the specimens of NSIL with HR-HPV, 33.3% expressed cyclin-A and 40% cyclin-E, while 100% of the LSILs expressed the 2 cyclins. On the other hand, 100% of the samples NSIL with LR-HPV presented an episomal pattern. Of the specimens of NSIL with HR-HPV, 56.6% exhibited an episomal pattern, 23.3% integrated and 20%, mixed. Among the LSILs, 90% were mixed and 10% integrated.

Conclusions:

The cyclins A and E are present in the LSILs that occur predominantly in mixed state in the presence of HR-HPV.

Common variants in the CRP gene are associated with serum C-reactive protein levels and body mass index in healthy individuals in Mexico

Variants in the C-reactive protein (CRP) gene have been found to be associated with various phenotypic traits. We evaluated the effect of four SNPs in the CRP gene on serum levels of protein and body mass index (BMI) in 150 unrelated Mexican subjects from 18 to 25 years old, without hypertension, non-overweight, and without inflammatory diseases, non-smoking and non-consumers of alcohol. Subjects were measured for BMI, waist circumference, blood pressure, and serum glucose and triglycerides. The identification of SNPs was performed by PCR-RFLP. Three of the four SNPs were associated with variation in serum levels of CRP, increased in TT (rs1130864) and GG (rs2794521) genotypes, and decreased in the AA genotype of rs1205. The TT genotype was associated with a significant increase in BMI (β = 1.1 kg/m², P = 0.04). Two haplotypes were significantly associated with increased serum levels of CRP, but not with BMI. We conclude that variation in the CRP gene affects serum protein levels.

In vitro and in vivo oxidation of methionine residues in small, acid-soluble spore proteins from Bacillus species

Methionine residues in alpha/beta-type small, acid-soluble spore proteins (SASP) of Bacillus species were readily oxidized to methionine sulfoxide in vitro by t-butyl hydroperoxide (tBHP) or hydrogen peroxide (H2O2). These oxidized alpha/beta-type SASP no longer bound to DNA effectively, but DNA binding protected alpha/beta-type SASP against methionine oxidation by peroxides in vitro. Incubation of an oxidized alpha/beta-type SASP with peptidyl methionine sulfoxide reductase (MsrA), which can reduce methionine sulfoxide residues back to methionine, restored the alpha/beta-type SASP's ability to bind to DNA. Both tBHP and H2O2 caused some oxidation of the two methionine residues of an alpha/beta-type SASP (SspC) in spores of Bacillus subtilis, although one methionine which is highly conserved in alpha/beta-type SASP was only oxidized to a small degree. However, much more methionine sulfoxide was generated by peroxide treatment of spores carrying a mutant form of SspC which has a lower affinity for DNA. MsrA activity was present in wild-type B. subtilis spores. However, msrA mutant spores were no more sensitive to H2O2 than were wild-type spores. The major mechanism operating for dealing with oxidative damage to alpha/beta-type SASP in spores is DNA binding, which protects the protein's methionine residues from oxidation both in vitro and in vivo. This may be important in vivo since alpha/beta-type SASP containing oxidized methionine residues no longer bind DNA well and alpha/beta-type SASP-DNA binding is essential for long-term spore survival.

The Bacillus subtilis dacB gene, encoding penicillin-binding protein 5*, is part of a three-gene operon required for proper spore cortex synthesis and spore core dehydration

Studies of gene expression using fusions to lacZ demonstrated that the Bacillus subtilis dacB gene, encoding penicillin-binding protein 5*, is in an operon with two downstream genes, spmA and spmB. Mutations affecting any one of these three genes resulted in the production of spores with reduced heat resistance. The cortex peptidoglycan in dacB mutant spores had more peptide side chains, a higher degree of peptide cross-linking, and possibly less muramic acid lactam than that of wild-type spores. These cortex structure parameters were normal in spmA and spmB mutant spores, but these spores did not attain normal spore core dehydration. This defect in spore core dehydration was exaggerated by the additional loss of dacB expression. However, loss of dacB alone did not alter the spore core water content. Spores produced by spmA and spmB mutants germinated faster than did those of the wild type. Spores produced by dacB mutants germinated normally but were delayed in spore outgrowth. Electron microscopy revealed a drastically altered appearance of the cortex in dacB mutants and a minor alteration in an spmA mutant. Measurements of electron micrographs indicate that the ratio of the spore protoplast volume to the sporoplast (protoplast-plus-cortex) volume was increased in dacB and spmA mutants. These results are consistent with spore core water content being the major determinant of spore heat resistance. The idea that loosely cross-linked, flexible cortex peptidoglycan has a mechanical activity involved in achieving spore core dehydration is not consistent with normal core dehydration in spores lacking only dacB.

Autoprocessing of the protease that degrades small, acid-soluble proteins of spores of Bacillus species is triggered by low pH, dehydration, and dipicolinic acid

The sequence-specific protease (termed GPR) that degrades small, acid-soluble proteins (SASP) during germination of spores of Bacillus species is synthesized during sporulation as an inactive precursor termed P46. Approximately 2 h later in sporulation, P46 is converted proteolytically to a smaller form, termed P41, which is active in vitro, but which does not act significantly on SASP in vivo until spore germination is initiated. While it appears likely that P46-->P41 conversion is an autoprocessing event, the mechanisms regulating P46-->P41 conversion in vivo are not clear. In this work we found that P46-->P41 conversion in vitro was stimulated tremendously in an allosteric manner by pyridine-2,6-dicarboxylic acid (dipicolinic acid [DPA]) plus Ca2+ but not by Ca2+ in combination with a variety of DPA analogs. The processing reaction stimulated by Ca(2+)-DPA was seen at pH 5.1 but not at pH 6.2 or 7, and under these conditions P46-->P41 conversion exhibited a linear time course and was a first-order reaction, indicative of an intramolecular autoprocessing reaction. At pH 5.1, P46-->P41 conversion was stimulated markedly by very high ionic strength. At pHs from 5.1 to 6.6, P46-->P41 conversion also occurred when P46 was dehydrated to approximately 54% relative humidity. This processing was stimulated markedly when dehydration was carried out in the presence of DPA and NaCl but was greatly decreased when dehydration was to 10, 33, or 75% relative humidity. Since previous work has shown that P(46)-->P(41) processing in vivo takes place (i) after a fall in forespore pH to 6.3 to 6.9 and approximately in parallel with (ii) DPA accumulation by the forespore and (iii) dehydration of the forespore, out new finings in vitro suggest that these three changes may synergistically trigger P(46)-->P(41) autoprocessing in the developing forespore. Presumably the conditions in vivo during this authoprocessing preclude significant attack of the P(41) generated on its SASP substrates.

The zymogen of the protease that degrades small, acid-soluble proteins of spores of Bacillus species can rapidly autoprocess to the active enzyme in vitro

The zymogen of the protease (GPR) that initiates protein degradation during spore germination in Bacillus species is not activated in vitro under normal physiological conditions. However, there is rapid, acid-pH-dependent, zero-order, proteolytic activation of the purified zymogen in high concentrations of dimethyl sulfoxide. These findings provide further evidence that GPR activates itself during sporulation.

Studies of the processing of the protease which initiates degradation of small, acid-soluble proteins during germination of spores of Bacillus species

Three mutant forms of the protease (GPR) that initiates degradation of small, acid-soluble spore proteins (SASP) during germination of spores of Bacillus species have been generated. In one variant (GPR delta), the putative pro sequence removed in conversion of the GPR zymogen (termed P46) to the active enzyme (termed P41) was deleted. GPR delta was expressed in both Escherichia coli and Bacillus subtilis as a polypeptide of 41 kDa (P41) which was active both in vivo and in vitro. The other two variants had changes in the sequence around the site where the pro sequence is removed, making this sequence even more like that recognized and cleaved by GPR in its SASP substrates. One of these variants (GPRS) was synthesized as P46S in both B. subtilis and E. coli, but P46S was processed to P41S earlier in B. subtilis sporulation than was wild-type P46. The second variant (GPREI) was made as P46EI but underwent extremely rapid processing to P41EI in both E. coli and B. subtilis. Expression of elevated (> 100-fold) levels of GPR delta or GPREI blocked sporulation at the time of synthesis of glucose dehydrogenase. Expression of elevated levels of GPRS or low levels (< 20% of the wild-type level) of GPR delta or GPREI did not retard sporulation, but the SASP level in the resultant spores was greatly reduced. Prolonged incubation of P41 delta, P41EI, or wild-type P41, either in vivo or with purified proteins in vitro, resulted in a second self-cleavage event generating a 39-kDa polypeptide termed P39. The sequence in the P(41)-->P(39) cleavage site was also quite similar to that recognized and cleaved by GPR in SASP. Together, these results strongly support a model in which activation of GPR during sporulation by conversion of P(46) to P(41) is a self-processing event triggered by a change in the spore core environment (i.e., dehydration) which precludes attack of the active P(41) on its SASP substrates. However, in the first minutes of spore germination, rapid spore core hydration allows rapid attack of active GPR on SASP.