Long-term outcomes of indocyanine green fluorescence imaging-guided laparoscopic lateral pelvic lymph node dissection for clinical stage II/III middle-lower rectal cancer: a propensity score-matched cohort study.

BACKGROUND: We previously reported that indocyanine green fluorescence imaging (ICG-FI)-guided laparoscopic lateral pelvic lymph node dissection (LPLND) was able to increase the total number of harvested lateral pelvic lymph nodes without impairing functional preservation. However, the long-term outcomes of ICG-FI-guided laparoscopic LPLND have not been evaluated. The aim of the present study was to compare the long-term outcomes of ICG-FI-guided laparoscopic LPLND to conventional laparoscopic LPLND without ICG-FI. METHODS: This was a retrospective, multi-institutional study with propensity score matching. The study population included consecutive patients with middle-low rectal cancer (clinical stage II to III) who underwent laparoscopic LPLND between January 2013 and February 2018. The main evaluation items in this study were the 3-year overall survival, relapse-free survival (RFS), local recurrence rate, and lateral local recurrence (LLR) rate. RESULTS: A total of 172 patients with middle-lower rectal cancer who had undergone laparoscopic LPLND were included in this study. After propensity score matching, 58 patients were matched in each of the ICG-FI and non-ICG-FI groups. There were no substantial differences in the baseline characteristics between the two groups. The ICG-FI group and non-ICG-FI group included 40 and 38 women and had a median age of 65 (IQR 60-72) and 66 (IQR 60-73) years, respectively. The median follow-up for all patients was 63.7 (IQR 51.3-76.8) months. The estimated respective 3-year overall survival, RFS, and local recurrence rates were 93.1%, 70.7%, and 5.2% in the ICG-FI group and 85.9%, 71.7%, and 12.8% in the non-ICG-FI group (p = 0.201, 0.653, 0.391). The 3-year cumulative LLR rate was 0% in the ICG-FI group and 9.3% in the non-ICG-FI group (p = 0.048). CONCLUSIONS: This study revealed that laparoscopic LPLND combined with ICG-FI was able to decrease the LLR rate. It appears that ICG-FI could contribute to improving the quality of laparoscopic LPLND and strengthening local control of the lateral pelvis. TRIALS REGISTRATION: This study was registered with the Japanese Clinical Trials Registry as UMIN000041372 ( http://www.umin.ac.jp/ctr/index.htm ).

Initial experience with the transanal approach for lateral pelvic lymph node dissection in rectal cancer.

BACKGROUND: The efficacy and safety of transanal lateral pelvic lymph node dissection (TaLPLND) in rectal cancer has not yet been clarified. The aim of the present study was to evaluate the short-term results as an initial experience of TaLPLND. METHODS: This retrospective study included patients with middle to lower rectal cancer who underwent TaLPLND from July 2018 to July 2021. Our institutions targeted lymph nodes in the internal iliac area and the obturator area for lateral pelvic lymph node dissection (LPLND). RESULTS: A total of 30 consecutive patients with rectal cancer were included in this analysis. The median age was 60 years (range, 36-83 years), and the male-female ratio was 2:1. The median operative time was 362 min (IQR, 283-661 min), and the median intraoperative blood loss was 74 ml (IQR, 5-500 ml). Intraoperative blood transfusion was required in one case. No cases required conversion to laparotomy. TaLPLND was performed bilaterally in 13 patients (43.3%). Five patients (16.7%) underwent LPLND with combined resection of the internal iliac vessels. The median distance of the distal margin from the anal verge was 20 mm. The pathological radial margin (pRM) was positive in one case, and the negative pRM rate was 96.7%. Short-term postoperative complications (Clavien-Dindo classification grade ≥ II) were observed in nine cases (30.0%). There were no cases of reoperation or mortality. The median number of harvested lateral pelvic lymph nodes was 11 (range, 3-28). On pathological examination, lateral pelvic lymph nodes were positive for metastasis in seven cases (23.3%). CONCLUSIONS: TaLPLND appeared to be beneficial from an oncological point of view because it was close to the upstream lymphatic drainage from the tumor. The short-term outcomes of this initial experience indicate that this novel approach is feasible.

Direct access CT for suspicion of brain tumour: an analysis of referral pathways in a population-based patient group.

BACKGROUND: Brain tumour patients see their primary care doctor on average three or more times before diagnosis, so there may be an opportunity to identify 'at risk' patients earlier. Suspecting a brain tumour diagnosis is difficult because brain tumour-related symptoms are typically non-specific. METHODS: We explored the predictive value of referral guidelines (Kernick and NICE 2005) for brain imaging where a tumour is suspected, in a population-based patient group referred for direct access CT of the head. A consensus panel reviewed whether non-tumour findings were clinically important or whether further investigation was necessary. RESULTS: Over a 5-year period, 3257 head scans were performed; 318 scans were excluded according to pre-specified criteria. 53 patients (1.8%) were reported to have intracranial tumours, of which 42 were significant (diagnostic yield of 1.43%). There were no false negative CT scans for tumour. With symptom-based referral guidelines primary care doctors can identify patients with a 3% positive predictive value (PPV). 559 patients had non-tumour findings, 31% of which were deemed clinically significant. In 34% of these 559 patients, referral for further imaging and/or specialist assessment from primary care was still thought warranted. CONCLUSION: Existing referral guidelines are insufficient to stratify patients adequately based on their symptoms, according to the likelihood that a tumour will be found on brain imaging. Identification of non-tumour findings may be significant for patients and earlier specialist input into interpretation of these images may be beneficial. Improving guidelines to better identify patients at risk of a brain tumour should be a priority, to improve speed of diagnosis, and reduce unnecessary imaging and costs. Future guidelines may incorporate groups of symptoms, clinical signs and tests to improve the predictive value.

Mid-term results of alumina ceramic unlinked total elbow arthroplasty with cement fixation for patients with rheumatoid arthritis.

Aims: The aim of this study was to report the mid-term clinical outcome of cemented unlinked J-alumina ceramic elbow (JACE) arthroplasties when used in patients with rheumatoid arthritis (RA). Patients and Methods: We retrospectively reviewed 87 elbows, in 75 patients with RA, which was replaced using a cemented JACE total elbow arthroplasty (TEA) between August 2003 and December 2012, with a follow-up of 96%. There were 72 women and three men, with a mean age of 62 years (35 to 79). The mean follow-up was nine years (2 to 14). The clinical condition of each elbow before and after surgery was assessed using the Mayo Elbow Performance Index (MEPI, 0 to 100 points). Radiographic loosening was defined as a progressive radiolucent line of >1 mm that was completely circumferential around the prosthesis. Results: The mean MEPI scores significantly improved from 40 (10 to 75) points preoperatively to 95 (30 to 100) points at final follow-up (p < 0.0001). Complications were noted in ten elbows (ten patients; 11%). Two had an intraoperative humeral fracture which was treated by fixation and united. One had a postoperative fracture of the olecranon which united with conservative treatment and one had a radial neuropathy which resolved. Further surgery was required for one with a dislocation, three with an ulnar neuropathy and one with a postoperative humeral fracture. Revision with removal of the components was performed in one elbow due to deep infection. There was no radiographic evidence of loosening around the components. With any revision surgery or revision with implant removal as the endpoint, the rates of survival up to 14 years were 93% (95% confidence interval (CI), 83.9 to 96.6) and 99% (95% CI 91.9 to 99.8), respectively, as determined by Kaplan-Meier analysis. Conclusion: With the appropriate indications, the mid-term clinical performance of the cemented JACE TEA is reliable and comparable to other established TEAs in the management of the elbow in patients with RA. Cite this article: Bone Joint J 2018;100-B:1066-73.

Prognostic significance of CD44 variant 2 upregulation in colorectal cancer.

BACKGROUND: CD133 and CD44 are putative cancer stem cell (CSC) markers in colorectal cancer (CRC). However, their clinical significance is currently unclear. Here, we evaluated primary CRC cell isolates to determine the significance of several CSC markers, including CD133 and CD44, as predictors of tumourigenesis and prognosis. METHODS: CD133- and CD44-positive cells from fresh clinical samples of 77 CRCs were selected by flow cytometric sorting and evaluated for tumourigenicity following subcutaneous transplantation into NOD/SCID mice. Cancer stem cell marker expression was examined in both xenografts and a complementary DNA library compiled from 167 CRC patient samples. RESULTS: CD44(+), CD133(+) and CD133(+)CD44(+) sub-populations were significantly more tumourigenic than the total cell population. The clinical samples expressed several transcript variants of CD44. Variant 2 was specifically overexpressed in both primary tumours and xenografts in comparison with the normal mucosa. A prognostic assay using qRT-PCR showed that the CD44v2(high) group (n=84, 5-year survival rate (5-OS): 0.74) had a significantly worse prognosis (P=0.041) than the CD44v2(low) group (n=83, 5-OS: 0.88). CONCLUSIONS: CD44 is an important CSC marker in CRC patients. Furthermore, CRC patients with high expression of CD44v2 have a poorer prognosis than patients with other CD44 variants.

Feasibility of 2nd generation STS retinal prosthesis in dogs.

We developed a 2(nd) generation suprachoroidal transretinal stimulation (STS) system with a 49 channel electrode array and implanted in 2 dogs. One month after surgery, all electrodes were functioning and the ocular fundus was normal in both dogs. The results indicate the 2(nd) generation STS retinal prosthesis is feasible and can be considered for clinical use.

Histone deacetylase inhibitors suppress mechanical stress-induced expression of RUNX-2 and ADAMTS-5 through the inhibition of the MAPK signaling pathway in cultured human chondrocytes.

OBJECTIVE: To investigate the inhibitory effects and the regulatory mechanisms of histone deacetylase (HDAC) inhibitors on mechanical stress-induced gene expression of runt-related transcription factor (RUNX)-2 and adisintegrin and metalloproteinase with thrombospondin motif (ADAMTS)-5 in human chondrocytes. METHODS: Human chondrocytes were seeded in stretch chambers at a concentration of 5 × 10(4)cells/chamber. Cells were pre-incubated with or without HDAC inhibitors (MS-275 or trichostatin A; TSA) for 12h, followed by uniaxial cyclic tensile strain (CTS) (0.5Hz, 10% elongation), which was applied for 30 min using the ST-140-10 system (STREX, Osaka, Japan). Total RNA was extracted and the expression of RUNX-2, ADAMTS-5, matrix metalloproteinase (MMP)-3, and MMP-13 at the mRNA and protein levels were examined by real-time polymerase chain reaction (PCR) and immunocytochemistry, respectively. The activation of diverse mitogen-activated protein kinase (MAPK) pathways with or without HDAC inhibitors during CTS was examined by western blotting. RESULTS: HDAC inhibitors (TSA: 10 nM, MS-275: 100 nM) suppressed CTS-induced expression of RUNX-2, ADAMTS-5, and MMP-3 at both the mRNA and protein levels within 1h. CTS-induced activation of p38 MAPK (p38), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) MAPKs was downregulated by both HDAC inhibitors. CONCLUSION: The CTS-induced expression of RUNX-2 and ADAMTS-5 was suppressed by HDAC inhibitors via the inhibition of the MAPK pathway activation in human chondrocytes. The results of the current study suggested a novel therapeutic role for HDAC inhibitors against degenerative joint disease such as osteoarthritis.

Bovine luteal prolactin receptor expression: potential involvement in regulation of progesterone during the estrous cycle and pregnancy.

In the present study, we performed quantitative reverse-transcription PCR (qPCR) to examine changes in gene expression of prolactin receptor (long form: l-PRLR; short form: s-PRLR) and 20α-hydroxysteroid dehydrogenase (20α-HSD; EC 1.1.1.149) in the bovine corpus luteum (CL) throughout the estrous cycle and pregnancy. Western blotting was used to determine protein abundance. Bovine CL were collected and luteal stages (n = 6/stage) were classified by macroscopic observation as early (d 1 to 4 after ovulation), mid (d 5 to 10), late (d 11 to 17), and regressing (d 18 to 20). A CL of pregnancy (n = 6) was determined by the presence of conceptus (d 28 to term). The mRNA for both forms of PRLR were expressed at all the luteal stages. Expression of s-PRLR and l-PRLR mRNA was less (P < 0.01) during early and regressing luteal stages compared with mid and late stages. Expression of s-PRLR mRNA in CL of pregnancy was greater (P < 0.01) than early, mid, and regressing CL and did not differ from late luteal stage expression. A greater (P < 0.01) expression of l-PRLR mRNA was observed in pregnant vs. early and regressing CL. In addition, qPCR showed the presence of 20α-HSD mRNA during all luteal stages of the estrous cycle, with the greatest (P < 0.01) expression observed in the regressing luteal stage. Western blotting revealed protein abundance of both PRLR isoforms during all luteal stages and pregnancy, with a predominance of the s-PRLR protein. Densitometry analysis indicated that protein abundances of s-PRLR were greater (P < 0.05) than l-PRLR during early, mid, and late luteal stages and did not differ during the regressing luteal stage. Protein abundances of 20α-HSD were least (P < 0.05) during the early luteal stage. In conclusion, results of the current study suggest a possible involvement of PRLR, especially s-PRLR, in the regulation of progesterone secretion and metabolism during the bovine estrous cycle and pregnancy.

Anterior transposition of the ulnar nerve with endoscopic assistance.

We treated 20 patients with cubital tunnel syndrome by anterior transposition of the ulnar nerve with endoscopic assistance. Five elbows were classified preoperatively as McGowan's stage 1, 11 as stage 2 and four as stage 3. Excellent outcomes were obtained in nine and good in eight patients. Three patients had fair results. Improvement of symptoms occurred in all patients. There were no serious complications. All ulnar nerves remained anteriorly transposed.

Production of good-quality porcine blastocysts by in vitro fertilization of follicular oocytes vitrified at the germinal vesicle stage.

We investigated survival, meiotic competence, cytoplasmic maturation, in vitro fertilization, and development of immature porcine (Sus scrofa) oocytes cryopreserved by a modified solid surface vitrification protocol. Cumulus-oocyte complexes (COCs) collected from follicles 3 to 6mm in diameter in abattoir-derived ovaries of prepubertal gilts were either vitrified (Vitrified group), subjected to cryoprotectant treatment (CPA group), or used without any treatment (Control group). Oocyte viability was assayed by staining with fluorescein diacetate. Live oocytes were matured in vitro and their meiotic progression investigated by nuclear staining. In a series of experiments, the glutathione (GSH) content of in vitro-matured oocytes and viability of cumulus cells were assayed simultaneously. The in vitro-matured oocytes were also fertilized and cultured in vitro to assess their ability to be fertilized and to develop to the blastocyst stage, respectively. The proportion of viable oocytes in the Vitrified group was significantly lower than that in the CPA and Control groups (27.7%, 90.4%, and 100%, respectively). Among the three groups, there were no differences in meiotic competence, cumulus viability, and GSH levels at the end of in vitro maturation. Fertilization parameters (i.e., rates of male pronucleus formation, monospermy, and second polar body extrusion) were also similar among groups. However, comparison of the developmental abilities of oocytes in the Vitrified, CPA, and Control groups revealed that the Vitrified group had a significantly reduced ability to undergo first cleavage (34.4%, 63.3%, and 69.0%) and to develop to the blastocyst stage (5.1%, 25.5%, and 34.6%). The mean total cell numbers in blastocysts after 6 d of culture were not significantly different among the Vitrified, CPA, and Control groups (40.3, 42.8, and 43.4). In conclusion, despite low survival rates and impaired development in the Vitrified group, meiotic competence, cytoplasmic maturation, and subsequent fertilization characteristics of surviving germinal vesicle oocytes were unaffected by vitrification, and high-quality blastocysts were produced from vitrified immature oocytes.

Cytoplasmic glutathione regulated by cumulus cells during porcine oocyte maturation affects fertilization and embryonic development in vitro.

It is generally accepted that cumulus cells support the nuclear maturation of mammalian oocytes. In the present study, we examined relationships between the cytoplasmic glutathione (GSH) content of porcine oocytes, and oocyte nuclear maturation, fertilization or subsequent embryonic development. Cumulus-oocyte complexes (COCs; control group) and oocytes denuded of cumulus cells after collection (DO 0h group) were cultured for 24h with dibutyryl cAMP, eCG and hCG (first culture step) and then for a further 20h without supplements (second culture step; 44h total culture). After the first culture step, some of the COCs were denuded, either completely (DO 24h group) or partly (H-DO 24h group), and then matured by the second culture step. Also, in the second culture step, some DOs were co-cultured with cumulus cells that had been pre-cultured for 24h (DO 24h+CC group). The maturation rates of all the cumulus-removed groups (DO 0h, DO 24h, H-DO 24h and DO 24h+CC groups) were lower (34.3-45.0%) than that of the control group (64.5%; P<0.05). The GSH contents of matured oocytes in the completely denuded groups (DO 0h, DO 24h and DO 24h+CC groups) were lower (4.03-5.26pmol/oocyte) than that of the control group (9.60pmol/oocyte; P<0.05); however, the H-DO 24h group had an intermediate value (7.0pmol/oocyte). The male pronuclear formation rates of completely denuded oocytes were lower (41.4-59.3%) than that of the control group (89.4%; P<0.05), whereas the H-DO 24h group had an intermediate rate (80.0%). The blastocyst formation rates of the completely denuded oocytes were lower (3.0-4.5%) than that of the control group (19.9%; P<0.05), and the H-DO 24h group again had an intermediate rate (11.6%). The GSH content was correlated with the rates of male pronuclear formation (P<0.01) and blastocyst formation (P<0.01), and also with the number of cells per blastocyst (P<0.01). In conclusion, we inferred that GSH synthesized by intact cumulus cells during maturation culture improved oocyte maturation and played an important role in fertilization and embryonic development.

PACAP stimulates the release of interleukin-6 in cultured rat Müller cells.

We have investigated the in vivo effect of PACAP on rat Müller cells that are the predominant glial element in the retina. Müller cells were treated with PACAP38, either alone or in the presence of the PACAP-selective antagonist, PACAP6-38. Cellular proliferation was determined by measuring the incorporation of bromodeoxyuridine, while interleukin-6 (IL-6) levels in the culture medium were examined using a B9 cell bioassay. In cultured rat Müller cells, the expression of PACAP receptor (PAC1-R) was assessed with immunohistochemistry using a PAC1-R-specific antiserum. PACAP stimulated IL-6 production in Müller cells at a concentration as low as 10(-12) M, which was not sufficient to induce cell proliferation. This elevation of IL-6 production was significantly inhibited by PACAP6-38. These data suggest that Müller cells are one of the target cells for PACAP, stimulating the release of IL-6, and providing a mechanism whereby PACAP exerts a significant neuroprotective effect in the retina.

[Surgical technique of aortic valve replacement for small aortic annulus in elderly patients].

Recent reports have shown that aortic valve replacement in elderly patients over 65 years with atherosclerotic aortic stenosis and a small aortic annulus is possible by using a small sized bioprosthesis (Carpentier-Edwards pericardial valve). Here we present out surgical technique. Firstly, the native calcified aortic valve was removed completely to gain total exposure of the surrounding aortic root and sinus of Valsalva like Bentall procedure. Secondly, a small sized bioprosthesis was implanted with intermittent noneverting mattress 2-0 sutures with spaghetti and small polytetrafluoroethylene (PTFE) felt. Aortic annulus is the dilated by inserting Hegar dilator sizing from 25 to 27 mm. Therefore, aortic valve replacement for small aortic annulus in intra- or supra-annular position should be easily accomplished. Good surgical results and hemodynamic state were achieved in 25 consecutive cases using this technique.

Alterations in follicular dynamics and steroidogenic abilities induced by heat stress during follicular recruitment in goats.

We investigated the changes in follicular dynamics and steroidogenic activity during heat stress in goats. Adult female goats were exposed to heat stress at 36 degrees C and 70% relative humidity for 48 h and then injected with prostaglandin (PG) F2alpha (the time of PGF2alpha injection was designated as 0 h). In experiment 1, every follicle greater than 2 mm in diameter was monitored by ultrasonography to investigate the follicular dynamics, and plasma concentrations of FSH, LH, progesterone, and oestradiol were measured from -48 h to 120 h. In experiment 2, the follicles were recovered from the goats at 48 h, and the concentration of oestradiol, the aromatase activity, and the LH receptor level in the follicles were determined. In control (non-heat-stressed) goats, ovulatory follicles were mainly recruited from -24 h to 0 h, whereas no follicles recruited during that period were ovulated in the heat-stressed goats. The timing of the recruitment of ovulatory follicles was delayed by heat stress by approximately 24 h. The plasma concentration of oestradiol in the heat-stressed goats was significantly lower from 36 to 54 h compared with the controls, although the concentrations of FSH and progesterone did not differ between the treatments. In addition, the concentration of oestradiol, the aromatase activity, and the LH receptor level in the follicles from heat-stressed goats were significantly lower compared with the controls. These results indicate that heat stress during follicular recruitment suppresses subsequent growth to ovulation, accompanied by decreased LH receptor level and oestradiol synthesis activity in the follicles.

Developmental competence and oxidative state of mouse zygotes heat-stressed maternally or in vitro.

Mammalian preimplantation embryos are sensitive to maternal and direct heat stress. However, the mechanisms by which heat stress affects early embryonic development in vivo or in vitro are unknown. This study examined whether heat-stress-induced loss of developmental competence in mouse embryos was mediated by physiological changes in the maternal environment or by high temperatures alone. After fertilization, zygotes at the same stage were heat-stressed at 39.5 degrees C for 12 h either maternally (measured by maternal rectal temperature) or directly in culture. Zygotes in each group were cultured at 37.5 degrees C for a further 84 h to assess their developmental ability. Neither type of heat stress affected the first cleavage rate. However, the proportion of embryos that developed to morulae or blastocysts was significantly lower in the maternally heat-stressed group, but not in the directly heat-stressed group. Moreover, maternal heat stress significantly reduced intracellular glutathione concentrations and enhanced hydrogen peroxide concentrations in both zygotes and two-cell embryos that were recovered immediately after heat stress or 12 h later, respectively. In contrast, direct heat stress had little effect on concentrations of glutathione or hydrogen peroxide in cultured early embryos. These results demonstrate that maternal heat stress at the zygote stage reduces the developmental ability of mouse embryos via physiological changes in the maternal environment that lead to an increase in intracellular oxidative stress on the embryo.

Non-myeloablative haematopoietic stem cell transplantation for severe aplastic anaemia with various complications.

We report a 20-year-old-male with severe aplastic anaemia who was treated with nonmyeloablative haematopoietic stem cell transplantation (NSCT) from a sibling donor. As the patient presented with complications consisting of mental retardation, severe obesity, a bone fracture, and recurrent infections, we selected NSCT instead of a myeloablative regimen, to reduce regimen-related toxicity (RRT). Conditioning therapy consisting of busulfan, fludarabine, antithymocyte globulin and FK506 was used to obtain immune suppression. RRT was limited and he is now in complete remission 19 months after NSCT. On day 91, he developed chronic graft-vs.-host disease; it was resolved by the combination of FK506, corticosteroids, and mycophenolate mofetil. Our experience contributes to the growing interest in NSCT as a modality for treating not only malignant haematological disorders associated with complications, but also nonmalignant haematological diseases.

Isolation and characterization of galectins in the mammalian retina.

PURPOSE: Previous studies have suggested that galectins may be involved in retinal adhesion and photoreceptor cell survival. To elucidate the underlying mechanisms, the authors isolated retinal galectins, determined their types and distributions, and investigated the validity of the hypothesis, using rat models. METHODS: An antibody was prepared against a bovine retinal lectin that was isolated by use of a lactose-agarose column. cDNA of the lectin was isolated by screening of a bovine retinal cDNA library, using the antibody, and then was sequenced. The cDNAs of rat retinal galectins were also isolated by means of polymerase chain reaction and used to produce an antibody against recombinant galectin-3. Using the described antibodies, the authors examined the distributions of galectins in bovine and rat retinas, morphologic changes of rat retinas induced by the antibodies, and distributional changes of galectins in constant-light-exposed rat retinas. RESULTS: The cDNAs of bovine galectin-1, rat galectin-1, and rat galectin-3 were isolated. Galectin-1 was found in various regions, including the retinal pigment epithelium, outer limiting membrane, and outer plexiform layer in bovine and rat retinas. Galectin-3 was increasingly detected in the cytoplasm of Müller cells after constant light exposure after an increase in its transcript. Retinal detachment and vacuolation of the outer plexiform layer were induced in rat eyes by intravitreous injection of the anti-galectin-1 antibody. CONCLUSIONS: Galectin-1 may be involved in adhesion of the photoreceptor and outer plexiform layers by interacting with glycoconjugates with beta-galactoside residues in the interphotoreceptor matrix and synaptic cleft matrix. Galectin-3 may increase in Müller cells of a degenerative rat retina, probably through endogenous anti-apoptosis.

Expression of alpha-catenin in alpha-catenin-deficient cells increases resistance to sphingosine-induced apoptosis.

Alpha-catenin, an intracellular protein, associates with the COOH-terminal region of cadherin cell adhesion molecules through interactions with either beta-catenin or gamma-catenin (plakoglobin). The full activity of cadherins requires a linkage to the actin cytoskeleton mediated by catenins. We transfected alpha-catenin-deficient colon carcinoma cells with a series of alpha-catenin constructs to determine that alpha-catenin expression increases the resistance to apoptosis induced by sphingosine. Two groups of constructs, containing deletions in either the middle segment of the molecule or the COOH terminus, induced morphological changes, cell compaction, and decreases in cell death. In alpha-catenin-expressing cells, inhibition of cadherin cell adhesion by treatment with anti-E-cadherin antibodies did not decrease the cells viability. alpha-Catenin expression partially suppressed the downregulation of Bcl-xL and the activation of caspase 3. Expression of p27kip1 protein, an inhibitor of cyclin-dependent kinases, was increased by alpha-catenin expression in low density cell cultures. The increased levels of p27kip1 correlated with both increased resistance to cell death and morphological changes in transfectants containing deletion mutants. Transfection-mediated upregulation of p27kip1 decreases sphingosine-induced cell death in alpha-catenin-deficient cells. We postulate that alpha-catenin mediates transduction of signals from the cadherin-catenin complex to regulate the apoptotic cascade via p27kip1.