Interaction of high-molecular-weight kininogen with endothelial cell binding proteins suPAR, gC1qR and cytokeratin 1 determined by surface plasmon resonance (BiaCore)

The physiologic activation of the plasma kallikrein-kinin system requires the assembly of its constituents on a cell membrane. High- molecular-weight kininogen (HK) and cleaved HK (HKa) both interact with at least three endothelial cell binding proteins: urokinase plasminogen activator receptor (uPAR), globular C1q receptor (gC1qR,) and cytokeratin 1 (CK1). The affinity of HK and HKa for endothelial cells are KD=7-52 nM. The contribution of each protein is unknown. We examined the direct binding of HK and HKa to the soluble extracellular form of uPAR (suPAR), gC1qR and CK1 using surface plasmon resonance. Each binding protein linked to a CM-5 chip and the association, dissociation and KD (equilibrium constant) were measured. The interaction of HK and HKa with each binding protein was zinc-dependent. The affinity for HK and HKa was gC1qR>CK1>suPAR, indicating that gC1qR is dominant for binding. The affinity for HKa compared to HK was the same for gC1qR, 2.6-fold tighter for CK1 but 53-fold tighter for suPAR. Complex between binding proteins was only observed between gC1qR and CK1 indicating that a binary CK1-gC1qR complex can form independently of kininogen. Although suPAR has the weakest affinity of the three binding proteins, it is the only one that distinguished between HK and HKa. This finding indicates that uPAR may be a key membrane binding protein for differential binding and signalling between the cleaved and uncleaved forms of kininogen. The role of CK1 and gC1qR may be to initially bind HK to the membrane surface before productive cleavage to HKa.

Workshop report: A practical approach and general principles of re-irradiation for in-field cancer recurrence

In-field cancer recurrence after previous adjuvant or radical radiotherapy presents particularly challenging clinical issues to the oncologists. A Canadian pattern of practice survey showed a wide range of approaches in treatment intent, planning and dose fractionation. A workshop on re-irradiation was conducted at the 2009 Canadian Association of Radiation Oncology annual scientific meeting, under the guidance of the Symptom Control Committee, in an effort to promote a uniform approach among radiation oncologists in their approach to re-irradiation. The workshop has made various recommendations in an effort to bring consistency among radiation oncologists across Canada to their approach towards re-irradiation.

Isolated FSH deficiency revealing a granulosa cell tumor

We report a case of a 41-year-old woman with a recent secondary amenorrhea and infertility. The initial assessment ruled out premature ovarian failure, polycystic ovary syndrome and led to suspect a hypothalamo-pituitary cause. However, the unusual hormone pattern with a very low level of FSH, normal levels of LH and estradiol, associated with a positive progesterone test suggested the presence of a FSH inhibiting factor: the unexpectedly high levels of inhibin B and AMH were suggestive of a granulosa cell tumor as showed by the radiologic findings. This prompted a surgical exploration, which confirmed the putative diagnosis. This case report illustrates the inhibin B and AMH values and the modern-day pelvic imaging data encountered in menstrual irregularities caused by a granulosa cell tumor.

[Prostate biopsies endothelin-1 expression: pt3a stage prognostic factor?]

AIM

The study evaluated the immunohistochemistry expression of endothelin-1 (ET-1) by prostate cancer (PCa) in prostate biopsies as an extracapsular stage (pT3a) prognostic factor.

MATERIAL AND METHOD

Sixty-eight radical prostatectomies (RP) were performed for clinically localised PCa (35 pT2 and 33 pT3a according to the 2002 pTNM classification). Age, digital rectal examination, initial PSA, biopsy Gleason score, positive biopsies ratio, specimen Gleason score, biopsy and RP specimen perineural neoplasic invasion, PCa DNA ploidy, PCa Ki-67 DNA image cytometry and biopsy and RP specimen ET-1 immunohistochemistry expression for both group were compared. Semi-quantitative ET-1 staining assessment was realised by the same pathologist.

RESULTS

pT3a group initial PSA was higher (p=0.032). No statistically difference was noticed between pT2 and pT3a groups for positive biopsies ratio, biopsy perineural neoplastic invasion and biopsy DNA ploidy determination. Biopsy Gleason score > or =7 was predictive of a pT3a stage (p=0.03). Statistically higher intensity of ET-1 PCa expression was observed in biopsies and specimens in pT3a group than in pT2 group (p<0.001 and p=0.01). In multivariate analysis, biopsy ET-1 PCa expression was an independent risk factor of pT3a stage with specificity 79 %, sensibility 69 %, predictive positive value 77 % and negative positive value 72 %. Combined with initial PSA > or =7, values were respectively 100 %, 76.9 %, 100 % and 57.1 %.

CONCLUSION

Endothelin-1 (ET-1) prostate cancer biopsy expression in our study was an independent prognostic factor of extracapsular stage (pT3a). Further studies will assess the relevance of ET-1 expression study in clinically localised PCa for active surveillance, curative treatment or targeted adjuvant therapy management.