Biomedical subjects

T Kudo

Publications and source records attributed to T Kudo.

At least 127 records · Page 7Linked to original sources

PubMed2000

GnRH agonist-suppressed expression of nitric oxide synthases and generation of peroxynitrite in adenomyosis.

Because overproduction of nitric oxide (NO) and peroxynitrite is known to cause tissue injury, the expression of NO synthases (NOS) and generation of peroxynitrite were investigated in adenomyosis. Immunoreactivities to endothelial and inducible NOS demonstrated phase-dependent changes in normal endometrium, and in eutopic endometrium of adenomyosis. However, NOS were expressed throughout the menstrual cycle in ectopic endometrium from the majority of patients with adenomyosis. Nitrotyrosine, a footprint of peroxynitrite, was detected concomitantly with NOS protein. This suggested that high doses of NO and superoxide are produced in the ectopic endometrium, presumably by stimulation with bioactive molecules such as cytokines and growth factors. The expression of NOS and generation of peroxynitrite were markedly reduced by administration of gonadotrophin-releasing hormone agonists (GnRHa). The suppression of serum concentrations of nitrite/nitrate, stable metabolites of NO, by long-term administration of GnRHa was also demonstrated. The suppression of synthesis of NO and/or peroxynitrite may be part of both the therapeutic and adverse effects of GnRHa therapy.

Adult↗

PubMed2000

Functional construction of the anti-mucin core protein (MUC1) antibody MUSE11 variable regions in a bacterial expression system.

A bacterial expression system for the variable region fragments (Fvs) of the anti-MUC1 tumor antigen antibody MUSE11 has been constructed. The Fv fragment showed binding specificity toward TFK-1 cells, with slightly reduced affinity compared to its parent IgG. The single-chain Fv fragment was arranged in two orders, VH-linker-VL and VL-linker-VH. However, linking the regions with a flexible peptide linker (GGGGS)(3) or with a shorter linker (GGGGS) led to a dramatic decrease in the biological activity toward the target antigen in both arrangements, suggesting that the MUSE11 antibody loses its activity when the domains are linked with polypeptide linkers. These results indicate that the variable region domains of the anti-MUC1 antibody MUSE11 have specificity only in the Fv form, and that linking the domains strongly reduces the association with its target antigen. Gel filtration analysis indicates that the scFv has a dimeric structure, suggesting that the inactivation of MUSE11 scFv is due to unfavorable intermolecular associations of the scFv chains. To our knowledge, this is the first report of a significant reduction in affinity caused by linking the variable domains in both arrangements, i.e., VH-VL and VL-VH.

Animals↗

PubMed2000

Construction of a diabody (small recombinant bispecific antibody) using a refolding system.

Diabodies are the recombinant bispecific antibodies (BsAbs), constructed from heterogeneous single-chain antibodies. Usually, diabodies have been prepared from bacterial periplasmic fraction using a co-expression vector (i.e. genes encoding two chains were tandemly located under the same promoter). Some diabodies, however, cannot be expressed as a soluble material owing to inclusion body formation, which limits the utilization of diabodies in various fields. Here we report an improved method for the construction of diabodies using a refolding system. As a model, a bispecific diabody binding to adenocarcinoma-associated antigen MUC1 and to CD3 on T cells was studied. One chain consisted of a VH specific for MUC1 linked to a VL specific for CD3 with a short polypeptide linker (GGGGS). The second was composed of a VL specific for MUC1 linked to a VH specific for CD3. The two hetero scFvs were independently obtained from intracellular insoluble fractions of Escherichia coli, purified, mixed stoichiometrically (at an equivalent molar ratio of 1:1) and refolded. The refolded two hetero scFv has a hetero-dimeric structure, with complete specificity for both target cells [i.e. MUC1 positive cells and CD3 positive lymphokine-activated killer cells with a T cell phenotype (T-LAK)]. Evaluation of the in vitro efficacy of T-LAK with the diabody by growth inhibition assay of cancer cells demonstrated maximum growth inhibition of cancer cells to reach approximately 98% at an effector:target ratio (E:T ratio) of 10, almost identical with that with anti-MUC1xanti-CD3 chemically synthesized BsAbs (c-BsAbs). This is the first report of the construction of a diabody using a refolding system.

Antibodies, Bispecific↗

PubMed2000

Milrinone attenuates serotonin-induced pulmonary hypertension and bronchoconstriction in dogs.

UNLABELLED: We determined whether milrinone, a phosphodiesterase III inhibitor, attenuates serotonin-induced (5-hydroxytryptamine [5HT]) pulmonary hypertension (PH) and bronchoconstriction. Dogs were anesthetized with pentobarbital (30 mg/kg + 2 mg. kg(-1). h(-1)). Bronchoconstriction and PH were elicited by 5HT (10 microg/kg + 1.0 mg. kg(-1). h(-1)). Pulmonary vascular resistance was used to assess PH. Bronchoconstriction was also assessed by changes in bronchial cross-sectional area obtained from our bronchoscopic method. At 30 min after 5HT infusion started, seven dogs were given milrinone: 0 (saline), 5, 50, 500, and 5000 microg/kg at 10-min intervals. The other 12 dogs were given milrinone 5000 microg/kg 30 min after 5HT infusion, and 5 min later were given propranolol 0.2 mg/kg (n = 6) or saline (n = 6) IV. The 5HT significantly increased percentage of pulmonary vascular resistance to 208% +/- 27% and decreased percentage of bronchial cross-sectional area to 52% +/- 5% of the basal. Milrinone significantly attenuated both PH and bronchoconstriction in a dose-dependent manner. However, -log 50% effective concentration (mean ED(50) in microg/kg) of milrinone for bronchoconstriction: 4.32 +/- 0.13 (47.6) was significantly smaller than that for PH: 3.84 +/- 0.29 (144.9) (P < 0.01). In addition, the spasmolytic effects of milrinone (5000 microg/kg) were not antagonized by propranolol, although this dose significantly increased plasma catecholamines. In conclusion, milrinone attenuates 5HT-induced PH and bronchoconstriction; however, this drug may be more sensitive to phosphodiesterase III in the airway smooth muscle than in pulmonary vascular smooth muscle. In addition, the relaxant effects could not be caused by beta-adrenoceptor activation because beta-blocker did not antagonize. IMPLICATIONS: We studied the effects of milrinone on serotonin-induced pulmonary hypertension and bronchoconstriction in dogs. Milrinone produces pulmonary vasodilation and bronchodilation, whose effects may not be caused by beta-adrenoceptor activation. In addition, this drug may be more sensitive to phosphodiesterase III in the airway smooth muscle than that in pulmonary vascular smooth muscle.

Animals↗

PubMed2000

A comparison of the spasmolytic effects of olprinone and aminophylline on serotonin-induced pulmonary hypertension and bronchoconstriction with or without beta-blockade in dogs.

In the present study in dogs, we compared with aminophylline the spasmolytic effects of olprinone, a novel phosphodiesterase 3 inhibitor, on serotonin-induced pulmonary hypertension (PH) and bronchoconstriction. Mongrel dogs were anesthetized with pentobarbital. PH and bronchoconstriction were induced with serotonin: 10 microg/kg + 1 mg x kg(-1) x h(-1), and assessed as % changes in pulmonary vascular resistance and bronchial cross-sectional area (basal = 100%). Initially, the relaxant effects of olprinone (n = 8: 0-1000 microg/kg) and aminophylline (n = 8: 0-100 mg/kg) were compared. Pulmonary vascular resistance and bronchial cross-sectional area were assessed before and 30 min after serotonin infusion began and 5 min after each dose of olprinone or aminophylline. We then determined whether propranolol (0.4 mg/kg) reversed the relaxation induced by olprinone (1000 microg/kg, n = 6) or aminophylline (100 mg/kg, n = 6) compared with saline (n = 6 each). Olprinone and aminophylline dose-dependently attenuated both PH and bronchoconstriction (olprinone > aminophylline: -logED(50)[mean] for PH and bronchoconstriction 5.37+/- 0.35[4.24 microg/kg] vs. 1.60+/-0.23[25.4 mg/kg] and 4.06+/-0.12[87.8 microg/kg] vs. 1.51+/-0.21[30.6 mg/kg], respectively). In addition, olprinone produced more potent pulmonary vasodilation than bronchodilation while aminophylline was equipotent. In addition, there was a significant increase in plasma catecholamines after olprinone (> or =100 microg/kg) and aminophylline (> or =10 mg/kg). With the exception of aminophylline-induced bronchodilation, propranolol did not reverse any of the other effects measured. Therefore, the spasmolytic effects of olprinone are independent of plasma catecholamines, while the bronchodilating effect of aminophylline may partially involve increased levels of circulating catecholamines.

Adrenergic beta-Antagonists↗

PubMed2000

Significance of tau phosphorylation and protein kinase regulation in the pathogenesis of Alzheimer disease.

The role of the phosphatidylinositol-3 kinase pathway in the hyperphosphorylation of tau protein was investigated in cultured cells. Human kidney 293T-cells were cotransfected with tau and glycogen synthase kinase-3 (GSK-3) genes or tau and protein kinase B genes. The phosphorylation of tau protein was increased by cotransfection with GSK-3; however, it was decreased by cotransfection with protein kinase B. Human neuroblastoma SY5Y cells were treated with wortmannin, an inhibitor of phosphatidylinositol-3 kinase, and only transient (after 1 hour) activation of GSK-3 and hyperphosphorylation of tau protein were observed. However, continuous inactivation of protein kinase B was observed, suggesting the involvement of protein kinases other than protein kinase B in the phosphorylation and inactivation of GSK-3 after 3 hours. In cells treated with wortmannin, protein kinase C delta fragments were observed, and the protein kinase C activity increased after 3 hours, whereas treatment of cells with z-DEVD-fmk, an inhibitor of caspase-3, inhibited fragmentation of protein kinase C delta and induced continuous activation of GSK-3. It is suggested that fragmentation of protein kinase C delta during the process of apoptosis results in the phosphorylation and the inactivation of GSK-3. Those data suggest that, in Alzheimer disease, more complicated mechanisms are involved in the process of phosphorylation of tau protein predominantly regulated by P13K pathway.

Alzheimer Disease↗

PubMed2000

Heavy-for-date infants: their backgrounds and relationship with gestational diabetes.

OBJECTIVE: Gestational diabetes (GDM) is closely related to birth weight. Heavy-for-date (HFD) infants, especially those with macrosomia, cause many perinatal complications. This study was performed to examine the backgrounds of HFD infants and to determine such infants' relationship with GDM. METHOD: Eighty cases of HFD infants who were delivered from 1996 through 1998 were analyzed. The random blood-glucose level was used for screening for GDM. RESULTS: Maternal body weight and the body-mass index before pregnancy and at delivery and the blood glucose level at the second trimester were positively correlated with birth weight. However, only 8.8% of HFD cases were detected by this screening method in the first trimester, and 11.3% of HFD cases were detected in the second trimester and only 1 case of borderline-type was detected by subsequent 75-g OGTT. CONCLUSIONS: Maternal obesity is an independent and more important risk factor for HFD infants than glucose intolerance.

Adult↗

PubMed2000

Triple marker screening for trisomy 21, trisomy 18 and open neural tube defects in singleton pregnancies of native Japanese pregnant women.

OBJECTIVE: To report the results of prenatal triple marker screening on a population of Japanese pregnant women. METHODS: From April 1994 through March 1999, a total of 32,925 native Japanese women with singleton pregnancies requested a triple marker-screening test. Multiples of the median values for 3 markers and individual risks for each patient were calculated following adjustment for the Japanese weight correction factor. The risk cut-off values used for Down syndrome (T21), open spina bifida (OSB) and trisomy 18 (T18) were 1: 295, 1: 290, and 1: 100, respectively. Follow-up information was collected postpartum and statistically analyzed. RESULTS: Detection rates (DR) of T21 for women less than 35 years, over 35 years and overall were 58, 94, and 83%, respectively. DR of T18 for women less than 35 years, over 35 years and overall were 75, 79, and 79%, respectively. DR of open neural tube defects (ONTD) was 100%. CONCLUSIONS: The first cumulative data of an intervention program and prospective follow-up studies in Japan have proven to be similar to other published reports. Individual risk values were calculated for each pregnancy for T21, T18 and ONTD. This screening program is more effective than age-dependent screening for detecting T21, T18 and ONTD pregnancies.

Adult↗

PubMed2000

The presence and role of the dopamine DA-2 receptor in the human decidua.

OBJECTIVES: Our objectives were to identify the presence of the dopamine DA-2 receptor in human decidua and to study its function in human parturition. METHODS: Human term decidual tissues were obtained during vaginal delivery and then homogenized. The P3 fraction was prepared for a radiolabeled receptor assay with [3H] spiperone as the ligand. Human decidual tissues obtained at cesarean section before the onset of labor were incubated in Krebs-Ringer buffer at 37 degrees C for 30 minutes in the presence of dopamine with or without (-)-sulpiride. The level of prostaglandin (PG) F in the medium was measured with a RIA kit. Differences were assessed with the Wilcoxon non-parametric test. RESULTS: Scatchard analysis showed a single class of binding sites having an equilibrium dissociation constant (Kd) of 2.25 +/- 0.59 nM (mean +/- SD) and a maximum binding capacity (Bmax) value of 166.5 +/- 77.7 fmol/mg protein (n = 3). Dopamine significantly increased the production of PGF. This stimulatory effect of dopamine was suppressed by (-)-sulpiride (p < 0.05; n = 7). CONCLUSION: The DA-2 receptor was demonstrated in the human decidua. Dopamine can stimulate PGF production via this receptor.

Decidua↗

PubMed2000

Function of a principal Na(+)/H(+) antiporter, ShaA, is required for initiation of sporulation in Bacillus subtilis.

ShaA (sodium/hydrogen antiporter, previously termed YufT [or NtrA]), which is responsible for Na(+)/H(+) antiporter activity, is considered to be the major Na(+) excretion system in Bacillus subtilis. We found that a shaA-disrupted mutant of B. subtilis shows impaired sporulation but normal vegetative growth when the external Na(+) concentration was increased in a low range. In the shaA mutant, sigma(H)-dependent expression of spo0A (P(S)) and spoVG at an early stage of sporulation was sensitive to external NaCl. The level of sigma(H) protein was reduced by the addition of NaCl, while the expression of spo0H, which encodes sigma(H), was little affected, indicating that posttranscriptional control of sigma(H) rather than spo0H transcription is affected by the addition of NaCl in the shaA mutant. Since this mutant is considered to have a diminished ability to maintain a low internal Na(+) concentration, an increased level of internal Na(+) may affect posttranscriptional control of sigma(H). Bypassing the phosphorelay by introducing the sof-1 mutation into this mutant did not restore spo0A (P(S)) expression, suggesting that disruption of shaA affects sigma(H) accumulation, but does not interfere with the phosphorylation and phosphotransfer reactions of the phosphorelay. These results suggest that ShaA plays a significant role at an early stage of sporulation and not only during vegetative growth. Our findings raise the possibility that fine control of cytoplasmic ion levels, including control of the internal Na(+) concentration, may be important for the progression of the sporulation process.

Bacillus subtilis↗

PubMed2000

Endocrine disrupting chemicals, phthalic acid and nonylphenol, activate Pregnane X receptor-mediated transcription.

Recently, Pregnane X receptor (PXR), a new member of the nuclear receptor superfamily, was shown to mediate the effects of several steroid hormones, such as progesterone, glucocorticoid, pregnenolone, and xenobiotics on cytochrome P450 3A genes (CYP3A) through the specific DNA sequence for CYP3A, suggesting that PXR may play a role in steroid hormone metabolism. In this paper, we demonstrated that phthalic acid and nonylphenol, endocrine-disrupting chemicals (EDCs), stimulated PXR-mediated transcription at concentrations comparable to those at which they activate estrogen receptor-mediated transcription using a transient reporter gene expression assay in COS-7 cells. However, bisphenol A, another EDC, had no effect on PXR-mediated transcription, although this chemical significantly enhanced ER-mediated transcription. In the yeast two-hybrid protein interaction assay, PXR interacted with two nuclear receptor coactivator proteins, steroid hormone receptor coactivator-1 and receptor interacting protein 140, in the presence of phthalic acid or nonylphenol. Thus, EDC-occupied PXR may regulate its specific gene expression through the receptor-coactivator interaction. In contrast, these EDCs had no effect on the interaction between PXR and suppressor for gal 1, a component of proteasome. Finally, the expression of CYP3A1 mRNA in the liver of rats exposed to phthalic acid or nonylphenol markedly increased compared with that in rats treated with estradiol, bisphenol A, or ethanol as assessed by competitive RT-PCR. These data suggest that EDCs may affect endocrine functions by altering steroid hormone metabolism through PXR.

Animals↗

PubMed2000

[Rapid reduction of a variety of organic functionalities including a new selective reduction with samarium diiodide].

This review deals with the rapid reduction of a variety of organic functionalities, including a new selective reduction of carboxylic acid, with samarium diiodide in the presence of additives under mild conditions. The single electron donor ability of samarium diiodide can be enhanced with ligands around Sm2+ when sufficient electrons are supplied from the ligands. Mechanistic consideration of this enhancement led to our finding that carboxylic acid, ester, amide, nitrile, pyridine and other functionalities were rapidly reduced with samarium diiodide in the presence of a base, acid, water and methanol as ligands at room temperature in good yields. Particularly, these systems directly reduced carboxylic acid into alcohol and a samarium diiodide--85% phosphoric acid system immediately reduced an aromatic primary amide to aldehyde in good yield. Pyridines were reduced to piperidines with a samarium diiodide-base or water system in excellent yields; also, the aromatic nucleus of phenol derivatives was rapidly reduced with a samarium diiodide-base system. Furthermore, these organic functionalities were rapidly reduced with an Sm or Yb metal-hydrochloric acid system. Aliphatic and aromatic carboxylic acids with a coexisting aldehyde or that bearing a formyl group were selectively reduced to the corresponding alcohols with a new samarium diiodide-samarium triflate-methanol-base or water system within a few minutes at room temperature in good to almost quantitative yield.

Amides↗

PubMed2000

[Understanding of molecular pathogenesis of Alzheimer's disease: implications for drug development].

Recent advances in the knowledge about Alzheimer pathogenesis indicate several tactics for the development of drugs to treat Alzheimer's disease. Firstly, the function of presenilin, the causative gene for most familial Alzheimer's disease, has been demonstrated to be the protease in the Notch signaling system. Presenilin cleaves the transmembrane domain of the C-terminal fragment of the Notch-1 molecule, which is generated by proteolysis by furin-like proteases. APP is also cleaved by presenilin at the gamma cut site, implying that presenilin is gamma-secretase itself or at least closely functioning with gamma-secretase. A recent paper has demonstrated that immunization of APP transgenic mouse with amyloid beta 42 may decrease and prevent amyloid deposition in brain tissue. This unique and novel approach may open the new tactics for developing anti-dementia drugs. Another important finding comes from the identification of the function of prolyl isomerase. It is demonstrated that pin 1, intra-nuclear prolyl isomerase, can restore the microtubule binding capacity of phosphorylated tau, which clearly shows a solid strategy for developing drugs for preventing neuronal degeneration.

Alzheimer Disease↗

PubMed2000

(+)-4-epi-alpha-bisabolol as a major sesquiterepene constituent in the leaves of two Rosa rugosa hybrids, Martin Frobisher and Vanguard.

During an investigation of the sesquiterpene phases and contents in leaves of several Rosa rugosa hybrids (hybrid rugosas), Martin Frobisher and Vanguard were found to accumulate a large amount of (+)-4-epi-alphabisabolol (1) as a single constituent. Although glandular trichomes of Martin Frobisher on the leaves are dense, this R. rugosa hybrid produces none of the carota-1,4dienaldehyde (2) or bisaborosaol A (3) that are both found as representative sesquiterpenes of the carotane and bisabolane classes, respectively, in a glandular trichome exudate of wild-type R. rugosa. Compound 1 was also apparent as a nearly single constituent detectable by GC in the leaf constituents of Vanguard possesses sparse glandular trichomes on the leaf. Martin Frobisher and Vanguard had likely lost their capability to form carotane-type sesquiterpenes and had also lost their activity to oxygenate the C-7 allyl methyl carbon of compound 1 to convert 3. The presence of (+)-4-epi-alphabisabolol-accumulating R. rugosa hybrids is significant when considering the sesquiterpene biogenesis of Rosa rugosa.

Molecular Structure↗

PubMed2000

Serum progesterone and estradiol-17beta concentrations in captive and free-ranging adult female japanese black bears (Ursus thibetanus japonicus).

Progesterone (P4) and estradiol-17beta (E2) concentrations were measured in serum samples obtained from 23 captive and 23 free-ranging adult female Japanese black bears. We then determined the relationship between changes in these sex steroid hormones and pregnancy. In all captive bears, which included animals of both known and unknown reproductive status, serum P4 concentrations were low from April to July, then tended to become higher after August. The levels then became much higher still in November and December, but returned to low levels in March. Serum P4 concentrations in eight captive pregnant bears, which had parturitions the following spring, increased gradually from August (0.5-2.4 ng/ml) to October (0.9-3.6 ng/ml), and achieved significantly higher maximum levels in December (7.2-18.0 ng/ml). Thereafter, serum P4 concentrations tended to decrease (3.5-6.4 ng/ml in January and 0.3-0.7 ng/ml in March). In all captive bears, serum E2 concentrations varied from April to October but showed low levels in November and December, and became high in January. Serum E2 concentrations in the eight pregnant bears were high in May (95.6-191.4 pg/ml) and varied from August to October (35.6-143.3 pg/ml). Subsequently, serum E2 concentrations in December dropped to significantly lower minimum levels (5.3-11.9 pg/ml) and increased again in January (67.6-153.1 pg/ml). Among the free-ranging bears, the data on serum P4 concentrations in eight bears led to expectations of pregnancy, whereas serum E2 concentrations showed no distinct evidence related to pregnancy. These results, particularly in captive pregnant bears, indicate that a marked increase of P4 in December might be accompanied by reactivation of the corpus luteum preceding implantation. Furthermore, changes in E2 concentrations suggested the possibility that a decline in December and an increase in January are associated with implantation and parturition, respectively.

Animals↗

PubMed2000

Ultrastructural and histochemical characterization of special muscle cells in the monkey small intestine.

The ultrastructure, three-dimensional arrangement, and histochemical features of special muscle cells in the monkey small intestine were investigated. The cells formed a special layer separated from the main part by a connective tissue space along the submucosal surface of the circular muscle coat. Scanning electron microscopy using alkali maceration demonstrated this inner sublayer to be a continuous thin sheet consisting of irregularly-shaped muscle cells equipped with many cytoplasmic projections and caveolae. Other ultrastructural features included direct contact with interstitial cells, due to their close association with nerve fibers of the deep muscular plexus. Histochemical examination revealed significant alkaline phosphatase activity and immunoreactivity for vascular smooth muscle alpha actin in these muscle cells, whereas the ordinary circular muscle cells were immunopositive for enteric smooth muscle gamma actin. These findings suggest that the special muscle cells play an important role in regulating the radial stretch of the monkey small intestinal wall.

Actins↗

PubMed2000

Expression of alpha-smooth muscle actin and fibronectin in tubulointerstitial lesions of cats with chronic renal failure.

OBJECTIVE: To examine renal expression of alpha-smooth muscle actin (alpha-SMA) and fibronectin in cats with tubulointerstitial nephritis (TIN) for use in predicting progression to renal fibrosis. ANIMALS: 19 cats with TIN and 9 cats without nephritis. PROCEDURE: Serum creatinine and BUN concentrations were measured. Indices for glomerular extra-cellular matrix (ECM), tubular injury (TI), and fibronectin were determined in renal specimens to quantify the extent of injury and fibrotic lesions. Expression of alpha-SMA in renal tissue was immunohistochemically detected, and correlations were evaluated between the alpha-SMA index and other histologic and clinical variables. RESULTS: The alpha-SMA index in tubulointerstitial areas (1.63 +/- 0.78) was significantly higher in cats with TIN, especially in the periglomerular and peritubular areas, than in cats without nephritis (0.20 +/- 0.14). The alpha-SMA index was significantly associated with the TI index (r2 = 0.70), fibronectin index (r2 = 0.95), BUN concentration (r = 0.64), and serum creatinine concentration () = 0.66). Of special interest was that interstitial alpha-SMA expression appeared evident in the kidneys at an early stage of TIN, prior to the onset of ECM deposition. CONCLUSION AND CLINICAL RELEVANCE: Analysis of results of histologic and clinical examinations revealed that interstitial alpha-SMA expression may have clinical importance and may be a useful early histologic marker for development of chronic renal failure in cats. An immunohistochemical examination for fibrogenic molecules (such as alpha-SMA expression) may provide fundamental information on the pathogenesis of early-stage renal disease and aid clinical management of cats with chronic renal failure, including TIN.

Actins↗

PubMed2000

Alteration of the CDKN2/p16 gene is not required for HPV-positive uterine cervical cancer cell lines.

To determine whether alterations of the CDKN2/p16 might be involved in HPV-positive cervical cancers, we examined for alterations of this gene and function of the protein p16 to interact with CDK4 in 5 cervical cancer cell lines. No alteration of this gene was detected. Proteins for p16 and CDK4 were normally expressed and function of p16 to interact with CDK4 was not abrogated in these cell lines. These cell lines were human papillomavirus (HPV)-positive and carried wild-type p53. These findings suggest that phosphorylation of pRb by CDK4 is not critical in the carcinogenesis or in the establishment of HPV-positive cervical cancer cell lines, since HPV E6 or E7 viral-transforming proteins inactivate p53 and pRb tumor suppressor protein function, resulting in deregulated progression of the cell cycle.

Cyclin-Dependent Kinase 4↗