Role of p27Kip1 and Cyclin-Dependent Kinase 2 in the Proliferation of Non-Small Cell Lung Cancer

The cell cycle is governed by a family of cyclin-dependent kinases (Cdks). Cdk2 forms a functional complex with cyclin E and plays a pivotal role in the regulation of G1/S transition. Cdk2 activity is negatively regulated by interactions with inhibitors. p27^Kip1, one of the most potent inhibitors of Cdk2, was recently identified as a powerful negative prognostic marker in non-small cell lung cancer as well as in colorectal and breast cancer. In the present study, the expression of p27 and Ki-67 antigen in nonneoplastic and cancerous lung tissues was determined by immunohistochemistry. After establishing that the antibody-measured p27 labeling index was a good reflection of the level of p27 expression measured by Western blotting, we show that p27 labeling index is decreased in cancerous lung tissues, compared with nonneoplastic lung tissues, and exhibits a significant inverse relation to the proliferation marker Ki-67 antigen, detected with monoclonal antibody MIB-1. Consistent with these data, all cancerous lung tissues showed enhanced degradation activity of p27 compared with nonneoplastic lung tissues and, in addition, increased levels of the phosphorylated form of Cdk2, as determined with Western blot analysis. The H1 histone kinase activity associated with Cdk2 was also increased in non-small cell lung cancers. Statistical analysis showed that proliferative activity as measured by MIB-1 labeling index was highly correlated with Cdk2 activity (r = 0.767, P < 0.0015). These results suggest that p27 and Cdk2 may play an important role in the proliferation of non-small cell cancer.     

Reciprocal/dichotomic expression of vimentin and B cell differentiation antigens in Reed-Sternberg's cells

Summary An immunohistochemical study of 63 cases of Hodgkin's disease was undertaken using formalin-fixed paraffin embedded tissue sections. The antibodies used were against L26, LN-1, LN-2, EMA (epithelial membrane antigen), Leu-M1, Vimentin, UCHL-1, S-100, and lysozyme. Hodgkin's disease could be divided into three groups: the first group was LN-1+/L26+/vimentin-, the second LN-1-/L26+/vimentin+, and the third LN-1-/L26-/vimentin+). Sixteen cases of follicular lymphomas were also examined and were all positive for LN-1 and L26 and negative for vimentin. Thus the vimentin negativity of the first group, including 7 nodular lymphocyte-predominant cases, gives further evidence of their germinal center B-cell origin. Since vimentin is expressed mainly in the immature stage of B-lymphocytes, the second group of Hodgkin's disease may represent immature B-cell Hodgkin's disease. In the third group, vimentin was present in Reed-Sternberg's (RS) and Hodgkin's (H) cells in 45 of the 48 cases (92.5%). In none of 48 cases were these cells positive for S-100 or lysozyme, but strong vimentin-positivity still suggested monocytic or histiocytic origin. The results of our study suggest, at least, divergent origin of RS's and H's cells.     

Characterization of the complete mitochondrial genome of the giant black Himalayan honeybee (<Emphasis Type="Italic">Apis laboriosa</Emphasis>) from Nepal

The giant black honeybee, Apis laboriosa, has been applied to the highlands of Southeast Asia, where the number of nests has been drastically decreasing. In this study, we first analyzed the complete mitochondrial genome of A. laboriosa from Nepal using Next sequencing technology. The mitochondrial genome is a circular molecule of approximately 1.5 kb, and includes 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and one AT-rich control region. The average AT content of the A. laboriosa mitochondrial genome is 84.7%. Start codons ATG and ATT were found in three and ten genes, respectively, while stop codons TAA and TAG were observed in 12 and 1 gene, respectively. All tRNA genes formed typical cloverleaf secondary structures, except for Ser (AGN) and Gln (Q). The heavy strand (H-strand) was predicted to have 9 PCGs and 14 tRNA genes, while the light strand (L-strand) was predicted to contain four protein-coding, eight tRNA, and two rRNA genes. The 1858 mutation sites that differ between A. laboriosa and Apis dorsata were evenly distributed throughout the mitochondrial genome. The phylogenetic relationship, inferred using 13 PCGs (based on maximum likelihood) was consistent with several previous studies that predicted a sister relationship between A. laboriosa and A. dorsata. A phylogenetic analysis inferred from the 13 mitochondrial PCGs, based on maximum likelihood, indicates that A. laboriosa and A. dorsata are very closely related. We found that the genetic distance between A. laboriosa and A. dorsata is 0.197, indicating that, while they are genetically similar enough to be considered sister species, they are indeed two distinct species.     

Analysis of 5'-end sequences of chimpanzee cDNAs

We constructed full-length enriched cDNA libraries from chimpanzee brain, skin, and liver tissues by the oligo-capping method to establish a database of sequences of chimpanzee genes. Randomly selected clones from the libraries were subjected to one-pass sequencing from their 5'-ends. As a result, we collected 6813 chimpanzee cDNA sequences longer than 400 bp. Homology search against human mRNA sequences (RefSeq mRNAs) revealed that our collection included sequences of 1652 putative chimpanzee genes. In order to calculate the sequence identity between human and chimpanzee homologs, we constructed 5'-end consensus sequences of 226 chimpanzee genes by aligning at least three sequences for individual genes. Sequence identity was estimated by comparing these consensus sequences and the corresponding sequences of their human homologs. The average sequence identity of the 5'-end cDNAs was 99.30%. Those of the 5'-UTRs and CDSs were 98.79% and 99.42%, respectively. The results confirmed that human and chimpanzee genes are highly conserved at the nucleotide level. As for amino acids, the average sequence identity was 99.44%. The average synonymous (K(S)) and nonsynonymous (K(A)) divergences were estimated to be 1.33% and 0.28%, respectively.     

Characterization of Multidrug-Resistant Group B Streptococci with Reduced Penicillin Susceptibility Forming Small Non-Beta-Hemolytic Colonies on Sheep Blood Agar Plates

We isolated and characterized three multidrug-resistant clinical isolates of group B streptococci with reduced penicillin susceptibility (PRGBS) that formed small non-beta-hemolytic colonies on sheep blood agar plates but grew well on chocolate agar plates. They can be overlooked in the bacterial identification step, leading to clinical misdiagnosis and treatment failure.     

Expression of E-cadherin, α-catenin, and β-catenin in tubulolobular carcinoma of the breast

Tubulolobular carcinoma (TLC) of the breast is a rare subtype of breast carcinoma categorized by Fisher et al. (Hum Pathol 8:679–683, 1977) as a tubular variant of lobular carcinoma. E-cadherin is a transmembrane glycoprotein, and complete loss of E-cadherin expression has been observed in invasive lobular carcinoma. Ductal carcinoma retains at least some expression of E-cadherin. Moreover, the adhesive function of E-cadherin is dependent on the integrity of the catenin components, which link E-cadherin to the actin filaments. In order to achieve improved categorization of TLC, we decided to investigate both E-cadherin and the catenins in TLCs and invasive lobular carcinomas. We reviewed all 1,430 cases of primary breast carcinoma that were surgically resected at Saitama Medical Center, Saitama Medical School, and at Saitama Red Cross Hospital between 1990 and 2005. Among these, 16 cases of TLC were reported retrospectively. The results were compared with those of 20 cases of invasive lobular carcinomas that were included as controls. Tumor tissue was immunostained for E-cadherin, α-catenin, and β-catenin. The presence of immunoreactivity in the TLC was seen in 12 (75%) cases for E-cadherin, in 8 (50%) cases for α-catenin, and in 10 (62.5%) cases for β-catenin. However, plasma-membrane-associated staining for E-cadherin, α-catenin, and β-catenin was completely absent in invasive lobular carcinomas. These results suggest the possibility that TLCs are not a variant of lobular carcinoma, but rather ductal carcinomas with a lobular growth pattern.