Abstract PD3-14: Phase 1 study of the antibody-drug conjugate SGN-LIV1A in patients with heavily pretreated triple-negative metastatic breast cancer

Background

LIV-1, a transmembrane protein and downstream target of STAT3, is highly expressed in breast cancer cells. It is associated with lymph node involvement and metastatic progression. SGN-LIV1A is an anti-LIV-1 antibody conjugated via a protease-cleavable linker to monomethyl auristatin E (MMAE). Upon binding to cell-surface LIV-1, SGN-LIV1A is internalized and releases MMAE, which disrupts microtubulin and induces apoptosis.

Methods

This ongoing, phase 1 study evaluates safety, tolerability, pharmacokinetics, and antitumor activity of SGN-LIV1A (q3wks IV) in women with LIV-1-positive, unresectable, locally advanced or metastatic breast cancer (LA/MBC) (NCT01969643). Patients (pts) with measurable disease and ≥2 prior cytotoxic regimens for LA/MBC are eligible. Pts with ≥ Grade 2 neuropathy are excluded. Response is assessed per RECIST v1.1; pts with stable disease (SD) or better can continue treatment until disease progression or intolerable toxicity. At completion of dose escalation in hormone receptor-positive/HER2-negative (HR+/HER2–) and triple-negative (TN) pts, expansion cohorts were opened to further evaluate safety and antitumor activity of monotherapy in TN pts. Tumor biopsies are evaluated for LIV-1 expression.

Results

To date, 69 pts (18 HR+/HER2–, 51 TN) have received a median of 3 cycles (range, 1–12) of SGN-LIV1A at doses of 0.5–2.8 mg/kg. Median age was 56 yrs. Pts had a median of 3 prior cytotoxic regimens for LA/MBC; 58 had visceral disease and 37 had bone metastases. No dose-limiting toxicities (DLTs) occurred in 19 DLT-evaluable pts; maximum tolerated dose was not exceeded at 2.8 mg/kg. Expansion cohorts of TN pts were opened at 2.0 and 2.5 mg/kg. Treatment-emergent adverse events (AEs) reported in ≥25% of pts were fatigue (59%), nausea (51%), peripheral neuropathy (44%), alopecia (36%), decreased appetite (33%), constipation (30%), abdominal pain, diarrhea, and neutropenia (25% each). Most AEs were Grade 1/2; AEs ≥ Grade 3 included neutropenia (25%) and anemia (15%). Febrile neutropenia occurred in 2 pts whose total dose exceeded 200 mg per cycle, including 1 treatment-related death due to sepsis. No other treatment-related deaths occurred on-study. Seven pts discontinued treatment due to AEs. In dose escalation, activity was observed in 17 efficacy evaluable (EE) HR+/HER2- pts, with a disease control rate (DCR= CR+PR+SD) of 59% (10 SD), including 1 pt with SD ≥24 wks. Among the 44 EE TN pts (dose escalation plus expansion cohorts), the objective response rate (ORR) was 32% (14 PR) with a confirmed PR rate of 21%, DCR was 64% (14 PR, 14 SD), and clinical benefit rate (CBR=CR+PR+SD ≥24 wks) was 36% (16 pts). For TN pts, median PFS was 11.3 wks (95% CI: 6.1, 17.1); 10 pts remain on treatment.

Of 631 MBC tumor samples of all clinical subtypes evaluated for LIV-1, 91% were positive; 75% had moderate-to-high expression (H-score ≥100).

Conclusions

LIV-1 is expressed in almost all MBC tumors. SGN-LIV1A monotherapy was generally well tolerated and showed encouraging antitumor activity in heavily pretreated TN MBC, with a PR rate of 32%, confirmed PR rate of 21%, and CBR (≥24 wks) of 36%. Response duration data continue to evolve. Enrollment continues in the TN monotherapy expansion cohort.

Citation Format: Modi S, Pusztai L, Forero A, Mita M, Miller KD, Weise A, Krop I, Burris III H, Kalinsky K, Tsai M, Liu MC, Hurvitz SA, Wilks S, Ademuyiwa F, Diab S, Han HS, Kato G, Nanda R, O'Shaughnessy J, Kostic A, Li M, Specht J. Phase 1 study of the antibody-drug conjugate SGN-LIV1A in patients with heavily pretreated triple-negative metastatic breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD3-14.

X-autosome and X-Y Translocations in Female Carriers: X-chromosome Inactivation Easily Detectable by 5-ethynyl-2-deoxyuridine (EdU)

Here we report one new case each of an X-autosome translocation (maternally derived), and an X-Y-chromosome translocation. Besides characterizing the involved breakpoints and/or imbalances in detail by molecular cyto-genetics, also skewed X-chromosome inactivation was determined on single cell level using 5-ethynyl-2-deoxyuridine (EdU). Thus, we confirmed that the recently suggested EdU approach can be simply adapted for routine diagnostic use. The latter is important, as only by knowing the real pattern of the skewed X-chromosome inactivation, correct interpretation of obtained results and subsequent reliable genetic counseling, can be done.

Abstract P6-12-04: Phase 1 study of the antibody-drug conjugate (ADC) SGN-LIV1A in patients with heavily pretreated metastatic breast cancer

Background

LIV-1, a transmembrane protein and downstream target of STAT3, is highly expressed in breast cancer cells. It is associated with lymph node involvement and metastatic progression. SGN-LIV1A is an anti-LIV-1 antibody conjugated via a protease-cleavable linker to monomethyl auristatin E (MMAE). Upon binding to cell-surface LIV-1, SGN-LIV1A is internalized and releases MMAE, which binds to tubulin and induces G2/M arrest and apoptosis.

Methods

This is an ongoing, phase 1 dose-escalation study evaluating safety, tolerability, pharmacokinetics, and antitumor activity of SGN-LIV1A (q3 wks IV) in women with LIV-1-positive, unresectable, locally advanced or metastatic breast cancer (LA/MBC) (NCT01969643). Patients (pts) with measurable disease and ≥2 prior cytotoxic regimens for LA/MBC were eligible. Pts with ≥Grade 2 neuropathy were excluded. Response was assessed per RECIST v1.1; pts with stable disease (SD) or better could continue treatment until disease progression or intolerable toxicity. At completion of dose escalation in hormone receptor-positive/HER2-negative (HR+/HER2–) and triple-negative (TN) pts, expansion cohorts were opened to further evaluate safety and antitumor activity of monotherapy in TN pts and combination therapy with trastuzumab (Tz) in HER2-positive (HER2+) pts. Pre- and post-treatment tumor biopsies were done to evaluate LIV-1 expression and other correlative endpoints.

Results

To date, 39 pts (18 HR+/HER2–, 21 TN) have received a median of 3 cycles (range, 1–10) of SGN-LIV1A monotherapy at doses of 0.5–2.8 mg/kg. Median age was 57 yrs (range, 33–79). At baseline, pts had a median of 4 prior cytotoxic regimens for LA/MBC (range, 2–8); 36 had visceral disease and 25 had bone involvement. No dose-limiting toxicities (DLT) occurred in 19 DLT-evaluable pts; maximum tolerated dose was not exceeded at 2.8 mg/kg. Treatment-emergent adverse events (AEs) reported in ≥30% of pts were: fatigue (64%), nausea (54%), alopecia (46%), decreased appetite (41%), constipation (39%), neutropenia (33%), and vomiting (31%). Peripheral neuropathy was reported in 9 pts (23%). Most AEs were Grade 1/2, except neutropenia (all ≥Grade 3). Four pts discontinued treatment due to AEs (acute respiratory distress syndrome, nausea, pneumonia, tachycardia). In dose escalation, modest activity was observed in 17 efficacy evaluable (EE) HR+/HER2- pts, with a disease control rate (DCR) of 59% (10 SD), including 1 pt with SD≥24 wks. Among the 17 EE TN pts (dose escalation plus cohort expansion), the overall response rate (ORR) was 41% (7 PR), DCR was 82% (7 PR, 7 SD) and clinical benefit rate (CBR=OR+SD≥24 wks) was 53% (9 pts). For TN pts, median PFS was 17.1 wks (95% CI: 6.0, 18.4); 6 pts remain on treatment.

Of 281 MBC tumor samples evaluated for LIV-1, 93% were positive; 81% had moderate-to-high expression (H-score ≥100).

Conclusions

LIV-1 is expressed in almost all MBC tumors. SGN-LIV1A monotherapy has been generally well tolerated and shown encouraging antitumor activity in heavily pretreated TN MBC, with a PR rate of 41% and a CBR at ≥24 wks of 53%. Response duration data continue to evolve. Enrollment continues in the TN monotherapy expansion cohort and the HER2+ combination cohort with Tz.

Citation Format: Forero-Torres A, Modi S, Specht J, Miller K, Weise A, Burris III H, Liu M, Krop I, Pusztai L, Kostic A, Li M, Mita M. Phase 1 study of the antibody-drug conjugate (ADC) SGN-LIV1A in patients with heavily pretreated metastatic breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-12-04.

Mouse white adipose tissue-derived mesenchymal stem cells gain pericentral and periportal hepatocyte features after differentiation in vitro, which are preserved in vivo after hepatic transplantation

AIM

Mesenchymal stem cells may differentiate into hepatocyte-like cells in vitro and in vivo. Therefore, they are considered a novel cell resource for the treatment of various liver diseases. Here, the aim was to demonstrate that mesenchymal stem cells may adopt both perivenous and periportal hepatocyte-specific functions in vitro and in vivo.

METHODS

Adipose tissue-derived mesenchymal stem cells were isolated from immunodeficient C57BL/6 (B6.129S6-Rag2(tm1Fwa) Prf1(tm1Clrk) ) mice and differentiated into the hepatocytic phenotype by applying a simple protocol. Their physiological and metabolic functions were analysed in vitro and after hepatic transplantation in vivo.

RESULTS

Mesenchymal stem cells changed their morphology from a fibroblastoid into shapes of osteocytes, chondrocytes, adipocytes and hepatocytes. Typical for mesenchymal stem cells, hematopoietic marker genes were not expressed. CD90, which is not expressed on mature hepatocytes, decreased significantly after hepatocytic differentiation. Markers indicative for liver development like hepatic nuclear factor 4 alpha, or for perivenous hepatocyte specification like cytochrome P450 subtype 3a11, and CD26 were significantly elevated. Periportal hepatocyte-specific markers like carbamoylphosphate synthetase 1, the entry enzyme of the urea cycle, were up-regulated. Consequently, cytochrome P450 enzyme activity and urea synthesis increased significantly to values comparable to cultured primary hepatocytes. Both perivenous and periportal qualities were preserved after hepatic transplantation and integration into the host parenchyma.

CONCLUSIONS

Adult mesenchymal stem cells from adipose tissue differentiated into hepatocyte-like cells featuring both periportal and perivenous functions. Hence, they are promising candidates for the treatment of region-specific liver cell damage and may support organ regeneration in acute and chronic liver diseases.

Atypical polycystic ovary syndrome--a genetic analysis

BACKGROUND/AIMS

Although polycystic ovary syndrome (PCOS) is a common endocrinopathy the pathogenesis is not entirely understood. Typically, high androgen levels are associated with increased virilization. We report 2 rare groups of patients with either unexpectedly high testosterone levels despite low virilization as well as patients with low testosterone levels despite high grade of virilization. One possibility for the atypical PCOS may be based on an altered androgen receptor (AR) signaling.

METHODS

6 patients and when available the parents were included in this study. Alterations of the metaphase chromosomes by GTG staining, the length of both the trinucleotide CAG- and GGC-repeats of the androgen receptor (AR) gene was determined by PCR, further the entire AR gene was sequenced and analyzed.

RESULTS

The GTG banding revealed no chromosomal alterations and the range of CAG- and GGC-repeat lengths are within the normal range. Interestingly, by sequencing of the entire AR gene few genetic mutations were identified.

CONCLUSION

The detected mutations do not alter the AR protein sequence but they change the codon usage towards less frequent codons that potentially may alter AR protein levels and androgen signaling. In addition to this, we postulate also other causes for manifestation of atypical PCOS, which may include AR-coregulators or epigenetic alterations. To our knowledge this is the first report of combining chromosomal analysis of PCOS patients with full sequencing of the human AR gene and linking codon usage to PCOS.

Back-gated spray-deposited carbon nanotube thin film transistors operated in electrolytic solutions: an assessment towards future biosensing applications

We report on back-gated carbon nanotube (CNT) thin-film transistors (CNTFETs) and their performance in electrolytic solutions to assess their suitability for future application as biosensors. Spray-deposited CNT networks were used as the sensitive active layer which offers the opportunity for integration on flexible sensing platforms at low-cost. We characterized the transistors' behavior in electrolytes by analyzing the response to different KCl solutions and buffers over a wide pH range. We observed a linear response of the drain current upon changing the pH in low molarity buffers and obtained an exponential dependence on the salt concentration of the electrolyte. These responses can be attributed to electrostatic gating effects that go along with shifts in the threshold voltage. Even though a lot of effort has been put into understanding the biosensing mechanism a detailed theory is still missing. Back-gated CNTFETs operated in electrolytic solutions can be a further tool to investigate and clarify the existing unsolved phenomena.

Five novel locations of Neocentromeres in human: 18q22.1, Xq27.1∼27.2, Acro p13, Acro p12, and heterochromatin of unknown origin

Since the first report in 1993, an ectopic centromere, i.e. neocentromere formation, has been reported in more than 100 small supernumerary marker chromosomes (sSMC), in 7 instances of centromere repositioning, and in about a dozen cases with more complex chromosomal rearrangements. Here we report 2 new cases with centromere repositioning and 3 neocentric sSMC consisting exclusively of heterochromatic material. Yet, no centromere formation was reported for the regions 18q22.1 and Xq27.1∼27.2 as it was observed in the 2 cases with centromere repositioning here; in both cases, cytogenetically an inversion was suggested. Two of the 3 neocentric sSMC were derived from a short arm of an acrocentric chromosome. The remainder neocentric sSMC case was previously reported and was stainable only by material derived from itself.

[Medium-term results of the Mayo™ short-stem hip prosthesis after avascular necrosis of the femoral head]

AIM

Short-stemmed prostheses are increasingly regarded as implants of first choice in coxarthrosis, especially in young patients. Despite promising short-term results, long-term follow-up studies are still lacking. Short-stemmed femoral implants are characterised by a metaphyseal osseointegration and strain distribution. Therefore a reduced stress shielding of the proximal femur is hypothesized and in some studies already proven. There is histological evidence that osteonecrosis (ON) of the femoral head may involve not only the intracapital region but also the femoral neck and metaphyseal area. This could lead to a higher rate of aseptic loosening of short-stemmed implants. The aim of this retrospective study was to analyze the midterm results of the Mayo™ short-stem prosthesis after ON with particular attention on osseointegration.

METHOD

From 2002-2004, in 21 patients (2 females, 19 males; mean age 45 years; mean BMI = 27) with secondary coxarthrosis after ON implantation of 26 Mayo™ Conservative Hips was performed. Postoperatively, all patients were mobilised with full weight-bearing. Using the specially developed Wristing® software, longitudinal stem migration and varus-valgus femoral stem alignment were examined digitally in anteroposterior X-rays taken immediately after surgery and in standing AP radiographs after 8.2 months and on average after 7.9 years (16 patients). The incidence of periprosthetic radiolucent lines was captured in the anteroposterior X-rays and assigned to the Gruen zones and a DEXA scan was performed. The X-rays of a matched control group with implantation of a Mayo™ short-stem prosthesis in primary coxarthrosis were analyzed by the same method. In all patients the Harris hip score (HHS) was obtained pre- and postoperatively.

RESULTS

There was no significant migration or valgus tilt of the Mayo™ prosthesis in the study and control groups during postoperative follow-up (paired t-test, p = 0.13 and 0.69, respectively). In six of 26 Mayo™-Stems 12 radiolucent lines (RL) of the Mayo™ prosthesis were observed. The control group showed at ten of 30 Mayo™ stems 17 radiolucent lines. The difference between the groups was not statistically different (chi-square test for the total number of RL: χ² = 0.001, p = 1.0 and χ² = 0.06, p = 0.79 for the number of Mayo™ stems with RL). The DEXA scan showed a slightly higher bone mineral density (BMD) in Gruen zones 3 and 5 compared with a control group: study group. In the study group the postoperative HHS was 93.5 (SD 5.6) compared to 94.2 (SD 6.9) in the control group (t-test, p = 0.63).

CONCLUSION

In the mid-term course no increased migration or tilt could be proven for Mayo™ short-stem THA in patients with osteonecrosis of the femoral head. Due to the absence of differences in the occurrence of radiolucent lines and the same results in the DEXA scan an unimpaired osseointegration of the Mayo™ stem is assumed. Therefore it is concluded that the Mayo™ Conservative Hip can be regarded as an alternative for operative treatment of ON of the femoral head.

Abstract P3-14-20: Phase 1 Dose-Escalation Study of the Investigational HER2/EGFR Inhibitor TAK-285 in Patients with Advanced Cancer

Background and Objectives: TAK-285 is a novel, orally active, dual HER2/EGFR inhibitor. Nonclinical data show that TAK-285 has high selectivity and specificity for binding to HER family kinases, and has demonstrated anti-tumor activity in a BT-474 mouse xenograft model of breast cancer. Nonclinical data also indicate that TAK-285 is not a substrate for the efflux transporters P-gp and BCRP and penetrates an intact blood-brain barrier in rats. This phase 1 dose-escalation study in patients with advanced cancer aimed to determine the safety and pharmacokinetic (PK) profile.

Methods: Adults had advanced histologically confirmed non-hematologic malignancies, life expectancy >12 weeks, adequate bone marrow, liver and renal function, ECOG PS 0-2, and were refractory to other treatments. Oral TAK-285 was escalated from 50 to 500 mg QD or BID for 21 or 28 consecutive days of a 28-day cycle until disease progression or unacceptable toxicity was observed.

Results: At the data cut-off of 04/23/10, the dose-escalation portion was complete, and the RP2D expansion cohort is ongoing. Preliminary data from the dose-escalation cohorts are reported. 43 patients (median age 60 years [43-76]) were enrolled: 30% ≥65 years, 51% female, and 86% white. Dose levels were 50 mg QD (N=4), 50 mg BID (N=7), and 75 mg BID (N=6) on d 1-21; and 150 mg (N=6), 225 mg (N=4), 325 mg (N=3), 400 mg (N=6), and 500 mg (N=7) BID on d 1-28. Median duration of exposure across all cohorts was 52 days (3-267). Four patients experienced a DLT in Cycle 1: 1 patient (50 mg BID) had Grade 3 pancreatitis; 1 patient (150 mg BID) had Grade 3 chest pain and Grade 3 hypoxia; 1 patient (500 mg BID) had Grade 3 increased ALT; and 1 patient (500 mg BID) had Grade 3 diarrhoea and Grade 3 hypokalaemia. The MTD was 400 mg BID d 1-28. 30 patients (70%) discontinued TAK-285, primarily due to disease progression (n=19, 44%) or an AE (n=9, 21%). Most frequent AEs were fatigue (37%), diarrhoea (35%), nausea (26%), anorexia (21%), vomiting (16%), and elevated AST (16%). 58% of patients had a drug-related AE; the most frequent were diarrhoea (21%), fatigue (19%), and rash (includes rash, rash maculo-papular and rash macular; 12%). 35% of patients had a grade 3/4 AE; the most common were hypokalaemia (7%), ileus, abdominal pain, and hypoxia (5% each). Grade 3/4 AEs related to TAK-285 were the DLTs in Cycle 1 and Grade 4 rhabdomyolysis in 1 patient (400 mg BID, d 1-28) in Cycle 3. 42% of patients experienced a serious AE (SAE); the only SAE seen in >1 patient was ileus (n=2). 4 (9%) patients had fatal AEs; none were considered related to TAK-285. Absorption was fast: plasma concentrations peaked 2-3 hours post-dose. Steady-state plasma exposures increased with dose in a greater than dose-proportional manner, with PK steady-state achieved by Day 8. Accumulation was noted with BID dosing (mean accumulation ratio, 2.4 at MTD); there was moderate fluctuation in plasma concentrations over the steady-state dosing interval (mean Cmax:Cmin ratio, 2.4 at MTD).

Conclusions: The MTD for TAK-285 was 400 mg BID d 1-28. The RP2D cohort is ongoing and includes CSF collection to assess the CNS distribution of TAK-285. Updated safety as well as efficacy data for the dose escalation cohorts will be presented.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-14-20.

Characterization of 23 small supernumerary marker chromosomes detected at pre-natal diagnosis: The value of fluorescence in situ hybridization

Small supernumerary marker chromosomes (sSMCs) cannot be identified or characterized unambiguously by conventional cytogenetic banding techniques. Until recently, the large variety of marker chromosomes, as well as the limitations in their identification, have presented a diagnostic problem. In order to determine the origin of sSMCs, we used a variety of fluorescence in situ hybridization (FISH) methods, including centromere-specific multicolor FISH, acrocentric specific multicolor FISH, subcentromere-specific multicolor FISH and multicolor FISH with whole chromosome paint probes. Moreover, uniparental disomy testing was in all cases attempted. From a total of 28,000 pre-natal samples from four diagnostic genetics laboratories in Greece, 23 (0.082%) supernumerary marker chromosomes were detected. The mean maternal age was 36.2 years (range 27-43) and the mean gestational age at which amniocentesis was performed was 18.5 weeks (range 16-23). Eighteen markers were de novo and 5 markers were inherited. Molecular cytogenetic methods were applied to determine the chromosomal origin and composition of the sSMC. In total, 17 markers were derived from acrocentric chromosomes (14, 15, 21 and 22) and 6 markers were non-acrocentric, derived from chromosomes 9, 16, 18, 20 and Y. Uniparental disomy was not detected in any of the cases studied. With regard to pregnancy outcome, 13 pregnancies resulted in normal healthy neonates, while 10 pregnancies were terminated due to ultrasound abnormalities. A total of 23 marker chromosomes from 28,000 pre-natal samples (0.082%) were identified. Molecular cytogenetic techniques provided valuable information on the chromosomal origin and composition of all the sSMCs. Especially in cases with normal ultrasound, the FISH results rendered genetic counseling possible in a category of cases previously considered a diagnostic problem. Abnormal outcome was observed in 10 cases (43,5%), 7 of which showed abnormal ultrasound findings. New technologies, such as array-comparative genomic hybridization, should be used in future genotype-phenotype correlation studies, although the high mosaicism rate poses a problem.

The case of an infertile male with an uncommon reciprocal X-autosomal translocation: how does this affect male fertility?

Infertility is defined as the inability to conceive after one year of regular unprotected intercourse. Constitutional numerical and/or structural chromosomal aberrations like sex-chromosome aberrations are one of the possible factors involved in fertility problems. Reciprocal translocations between an X-chromosome and an autosome are rarely seen in men. Male carriers of an X-autosome translocation are invariably sterile, regardless of the position of the breakpoint in the X-chromosome. Breakpoints in autosomal chromosomes could also be involved in male infertility. In this paper, we describe a 31-year-old male with azoospermia. GTG banding with high resolution multicolor-banding (MCB) techniques revealed a karyotype 46,Y,t(X;1)(p22.3;q25), and we discuss how the breakpoint of this translocation could affect male infertility. As a conclusion, cytogenetic evaluation of infertile subjects with azoospermia should be considered in the first place before in vitro fertilisation procedures are planned.

Prevalence of CYP450 gene variations in patients with type 2 diabetes

BACKGROUND

Drug degradation in the human organism is driven by detoxification mechanisms that can be affected in their efficiency by genetic mutations. The purpose of this pilot investigation was to investigate whether Type 2 diabetes is associated with mutations in prominent members of the CYP 450 isoenzyme family.

METHODS

Genomic DNA was isolated from EDTA blood samples of 203 Caucasian subjects (101 patients with Type 2 diabetes and 102 non-diabetic subjects, age (mean +/- STD): 49 +/- 16 years) was analyzed. Genomic DNA was isolated from EDTA blood. Mutation analysis for CYP2C8 (*2/*3/*4), CYP2C9 (*2/*3), CYP2C19 (*2/*3), CYP2D6 (*3/*4/*5/*6) and PPARgamma (P12A) was performed by means of real-time PCR methods (Light-Cycler, Roche Diagnostics, Indianapolis, IN, USA).

RESULTS

The genotyping revealed the following allele frequency distributions for the two investigated groups: CYP2C8: *2 (type 2 diabetes 3% vs. 1%, n.s.), *3 (16% vs. 3%, n.s.), *4 (15% vs. 2%, p < 0.05), CYP2C9: *2 (20% vs. 24%, n.s.), *3 (22% vs. 21%, n.s.), CYP2C19: *2 (23% s. 33%, n.s.), *3 (0% vs. 0%, n.s.), CYP2D6: *3 (3% vs. 4%, n.s.), *4 (40% vs. 37%, n.s.), *5 (3% vs. 2%, n.s.), *6 (0% vs. 0%, n.s.), PPARgamma P12A (15% vs. 21%, n.s.), i.e. all but one mutation (CYP2C8*4) were found with equal prevalence in the two cohorts.

CONCLUSIONS

In this pilot investigation, we found an increased prevalence of the CYP2C8*4 mutation in the Type 2 diabetic patient group. This may result in a modification of drug degradation and drug efficacy in these patients and may have an influence, e.g. on the choice of anti-diabetic drugs. However, further trials are necessary in order to confirm our findings.

First case of a neocentromere formation in an otherwise normal chromosome 7

According to cytogenetic and molecular cytogenetic characterization, an otherwise not-altered chromosome 7 formed a neocentromere in band 7q32.1 in a clinically normal female. The alpha satellite sequence D7Z1 remained in its place but was not used for formation of the primary chromosomal incision. Similar observations of centromere repositioning have been made for chromosomes 3 (2x), 4, 8 and Y (2x). Even though data is available for some neocentromeres whose positions are correlated with evolutionary new centromeres for 7q32.1, no correlation could be found for an ancestral inactivated centromere in any of the presently living primates. Overall, we report a new case of centromere repositioning at a position not known to harbor an ancestral inactivated centromere.

10p11.2 to 10q11.2 is a yet unreported region leading to unbalanced chromosomal abnormalities without phenotypic consequences

Directly transmitted unbalanced chromosomal abnormalities (UBCA) or euchromatic variants (EV) were recently reported for >50 euchromatic regions of almost all human autosomes. UBCA and EV are comprised of a few megabases of DNA, and carriers are in many cases clinically healthy. Here we report on partial trisomies of chromosome 10 within the pericentromeric region which were detected by standard G banding. Those were referred for further delineation of the size of these duplicated regions for molecular cytogenetics and/or array-CGH. Partial trisomies of chromosome 10 in the pericentromeric region were identified prenatally in seven cases. A maximum of three copies of the region from 10p12.1 to 10q11.22 was observed in all cases without apparent clinical abnormalities. The imbalances were either caused by a direct duplication in one familial case or by de novo small supernumerary marker chromosomes (sSMC). Thus, we report a yet unrecognized chromosomal region subject to UBCA detected in seven unrelated cases. To the best of our knowledge, this is the first report of a UBCA in the pericentromeric region of chromosome 10 that is not correlated with any clinical consequences.

Hepatocyte differentiation of mesenchymal stem cells from human adipose tissue in vitro promotes hepatic integration in vivo

OBJECTIVE

The hepatic integration of human adipose tissue derived mesenchymal stem cells (hAT-MSCs) in vivo with or without prior differentiation to hepatocyte-like cells in vitro was investigated.

METHODS AND RESULTS

Cells, isolated either from peritoneal or subcutaneous adipose tissue, expressed mesenchymal stem cell surface markers and featured multiple lineage differentiation. Under conditions favouring hepatocyte differentiation, hAT-MSCs gained hepatocytic functions in vitro including urea formation, glycogen synthesis, cytochrome P450 enzyme activity, and expression of hepatocyte-specific transcripts of carbamoylphosphate synthetase, albumin and cytochrome P450 type 3A4 (CYP3A4). Transgenic expression of green fluorescent protein emerged upon hepatocyte differentiation when driven by the hepatocyte-specific promoter of the cytosolic phosphoenolpyruvate carboxykinase gene but was constitutive from the ubiquitin gene promoter. Human AT-MSCs were transplanted into livers of immunodeficient Pfp/Rag2-/- mice with or without prior hepatocyte differentiation in vitro. Donor-derived human cells engrafted in the mouse host liver predominantly in the periportal region of the liver lobule. They expressed HepPar1 and albumin, typical features of differentiated human hepatocytes, in the otherwise negative mouse liver background. Engraftment was significantly more efficient using hAT-MSCs pre-differentiated to hepatocyte-like cells in vitro as compared with undifferentiated cells.

CONCLUSIONS

Pre-differentiation of human MSCs from adipose tissue into hepatocyte-like cells in vitro facilitates long term functional hepatic integration in vivo.

A Neocentric Isochromosome Yp Present as Additional Small Supernumerary Marker Chromosome – Evidence against U-Type Exchange Mechanism?

Here we report the first case of an inverted duplicated neocentric small supernumerary marker chromosome present in a karyotype 47,XX,+mar(Y). As expected a partial disomy of Ypter to Yp11.2 did not lead to any major malformations. However, the formation of an inverted duplicated chromosome from a Y chromosome is not possible by a U-type exchange, as has been suggested for such kind of neocentric marker chromosomes. Thus, some evidence is here provided that this concept might not always be true.

A new unbalanced chromosomal abnormality in 1q31.1 to 1q32 without phenotypic consequences

A familial duplication in the long arm of one chromosome 1 was detected due to recurrent abortions in a couple. The duplication was present in the male partner of the couple and in his mother, both clinically healthy. By reverse FISH, the duplication was determined to be located in 1q31. Multicolor banding (MCB) and application of locus-specific probes narrowed down the breakpoints to 1q31.1 and 1q32. The duplication spans a region of 13.9 Mb. None of the two breakpoints was colocalized with a known fragile site in 1q31.2, which, however, was duplicated. To the best of our knowledge, this is the first report of an unbalanced chromosome abnormality in this region that is not correlated with any clinical consequences.

Parental-origin-determination fluorescence in situ hybridization distinguishes homologous human chromosomes on a single-cell level

The differentiation of homologous chromosomes as well as their parental origin can presently be conducted and determined exclusively by molecular genetic methods using microsatellite or SNP analysis. Only in exceptional cases is a distinction on a single-cell level possible, e.g. due to variations within the heterochromatic regions of chromosomes 1, 9, 16 and Y or the p-arms of the acrocentric chromosomes. In the absence of such polymorphisms, an individual distinction of the homologous chromosomes is not currently possible. Consequently, various questions of scientific and diagnostic relevance are unable to be answered. Based on the recently detected large-scale copy-number variations (LCV) or copy-number polymorphisms (CNP) spanning up to several megabase pairs of DNA, in this study, a molecular cytogenetic technique for the inter-individual differentiation of homologous chromosomes called parental-origin-determination fluorescence in situ hybridization (pod-FISH) is presented. All human chromosomes were covered with 225 LCV- and/or CNP-specific BAC probes, and one- to five-color chromosome-specific pod-FISH sets were created, evaluated and optimized. We demonstrated that pod-FISH is suitable for single-cell analysis of uniparental disomy (UDP) in clinical cases such as Prader-Willi syndrome caused by maternal UPD. A rare clinical case with a mosaic form of a genome-wide isodisomy was used to determine the detection limits of pod-FISH. Additionally we analyzed the informativeness of conventional microsatellite analysis for the first time and compared the results to pod-FISH. With this new possibility to study the parental origin of individual human chromosomes on a single-cell level, new doors for diagnostic and basic research are opened.

Optically controlled thermal management on the nanometer length scale

The manipulation of polymers and biological molecules or the control of chemical reactions on a nanometer scale by means of laser pulses shows great promise for applications in modern nanotechnology, biotechnology, molecular medicine or chemistry. A controllable, parallel, highly efficient and very local heat conversion of the incident laser light into metal nanoparticles without ablation or fragmentation provides the means for a tool like a 'nanoreactor', a 'nanowelder', a 'nanocrystallizer' or a 'nanodesorber'. In this paper we explain theoretically and show experimentally the interaction of laser radiation with gold nanoparticles on a polymethylmethacrylate (PMMA) layer (one-photon excitation) by means of different laser pulse lengths, wavelengths and pulse repetition rates. To the best of our knowledge this is the first report showing the possibility of highly local (in a 40 nm range) regulated heat insertion into the nanoparticle and its surroundings without ablation of the gold nanoparticles. In an earlier paper we showed that near-infrared femtosecond irradiation can cut labeled DNA sequences in metaphase chromosomes below the diffraction-limited spot size. Now, we use gold as well as silver-enhanced gold nanoparticles on DNA (also within chromosomes) as energy coupling objects for femtosecond laser irradiation with single-and two-photon excitation. We show the results of highly localized destruction effects on DNA that occur only nearby the nanoparticles.