Fever-range whole body thermotherapy combined with oxaliplatin: a curative regimen in a pre-clinical breast cancer model

PURPOSE

Studies were conducted to test whether fever-range whole body thermal therapy would boost the efficacy of oxaliplatin chemotherapy without substantial toxicity.

MATERIALS AND METHODS

The effect of mild heat (40 degrees C) on oxaliplatin cytotoxicity, cellular uptake, and platinum-DNA adduct formation was studied in vitro using the MTLn3 tumour cell line. In vivo oxaliplatin was administered at various doses and times before, during and after fever-range thermal therapy (6 h at 40 degrees C) to rats bearing an MTLn3 mammary adenocarcinoma. Tumour growth, survival, and toxicity were measured to determine treatment outcome.

RESULTS

Heating halved the oxaliplatin IC-50 dose for MTLn3 cells. Cellular uptake of platinum and platinum adducts increased by 34% and 36%, respectively, with heat. In vivo, 50% of all rats given 10 mg/kg oxaliplatin 24 h before thermal therapy were completely immunologically cured, while a further 11% regressed their primary tumour but ultimately succumbed to metastases, and 17% experienced a limited response with increased survival. The curative response occurred only in a narrow range of doses, with most cures at 10 mg/kg. Thermochemotherapy-treated, but uncured, animals had delayed incidence and slowed growth of metastases. Anti-tumour efficacy was greatest, and toxicity was least, when oxaliplatin was administered 12 or 24 h before fever-range whole body thermal therapy.

CONCLUSIONS

When properly dosed and scheduled, oxaliplatin thermochemotherapy achieved permanent eradication of all primary and metastatic tumours in 50% of animals, seemingly through an immune response. Successful clinical translation of this protocol would yield hitherto unseen cures and substantial improvement in quality of life.

Pigeonpea genomics initiative (PGI): an international effort to improve crop productivity of pigeonpea (Cajanus cajan L.)

Pigeonpea (Cajanus cajan), an important food legume crop in the semi-arid regions of the world and the second most important pulse crop in India, has an average crop productivity of 780 kg/ha. The relatively low crop yields may be attributed to non-availability of improved cultivars, poor crop husbandry and exposure to a number of biotic and abiotic stresses in pigeonpea growing regions. Narrow genetic diversity in cultivated germplasm has further hampered the effective utilization of conventional breeding as well as development and utilization of genomic tools, resulting in pigeonpea being often referred to as an 'orphan crop legume'. To enable genomics-assisted breeding in this crop, the pigeonpea genomics initiative (PGI) was initiated in late 2006 with funding from Indian Council of Agricultural Research under the umbrella of Indo-US agricultural knowledge initiative, which was further expanded with financial support from the US National Science Foundation's Plant Genome Research Program and the Generation Challenge Program. As a result of the PGI, the last 3 years have witnessed significant progress in development of both genetic as well as genomic resources in this crop through effective collaborations and coordination of genomics activities across several institutes and countries. For instance, 25 mapping populations segregating for a number of biotic and abiotic stresses have been developed or are under development. An 11X-genome coverage bacterial artificial chromosome (BAC) library comprising of 69,120 clones have been developed of which 50,000 clones were end sequenced to generate 87,590 BAC-end sequences (BESs). About 10,000 expressed sequence tags (ESTs) from Sanger sequencing and ca. 2 million short ESTs by 454/FLX sequencing have been generated. A variety of molecular markers have been developed from BESs, microsatellite or simple sequence repeat (SSR)-enriched libraries and mining of ESTs and genomic amplicon sequencing. Of about 21,000 SSRs identified, 6,698 SSRs are under analysis along with 670 orthologous genes using a GoldenGate SNP (single nucleotide polymorphism) genotyping platform, with large scale SNP discovery using Solexa, a next generation sequencing technology, is in progress. Similarly a diversity array technology array comprising of ca. 15,000 features has been developed. In addition, >600 unique nucleotide binding site (NBS) domain containing members of the NBS-leucine rich repeat disease resistance homologs were cloned in pigeonpea; 960 BACs containing these sequences were identified by filter hybridization, BES physical maps developed using high information content fingerprinting. To enrich the genomic resources further, sequenced soybean genome is being analyzed to establish the anchor points between pigeonpea and soybean genomes. In addition, Solexa sequencing is being used to explore the feasibility of generating whole genome sequence. In summary, the collaborative efforts of several research groups under the umbrella of PGI are making significant progress in improving molecular tools in pigeonpea and should significantly benefit pigeonpea genetics and breeding. As these efforts come to fruition, and expanded (depending on funding), pigeonpea would move from an 'orphan legume crop' to one where genomics-assisted breeding approaches for a sustainable crop improvement are routine.

Effect of synthetic cannabinoid HU210 on memory deficits and neuropathology in Alzheimer's disease mouse model

Cannabinoids have been shown to increase neurogenesis in adult brain, as well as protect neurons from excitotoxicity, calcium influx, inflammation, and ischemia. Recent studies have shown that synthetic cannabinoids can alleviate water maze impairments in rats treated with intracranial amyloid beta protein (Abeta); however it is unknown whether this effect is due to the cannabinoids' anti-inflammatory properties or whether it affects Abeta processing. Here we investigate whether cannabinoids have any effect on Alzheimer's disease in vivo. We found that HU210, a potent synthetic cannabinoid, did not improve water maze performance or a contextual fear conditioning task in an APP23/PS45 double transgenic mouse model of AD. HU210 had no effect on APP processing and Abeta generation, as well as neuritic plaque formation in the brains of AD transgenic mice. Our study showed that synthetic cannabinoid HU210 had no beneficial effects on AD neuropathology and behavioral deficits of AD model mice, which advises caution of such drug's application in AD therapies.

Abstract 3513: The underlying basis for divergent cell cycle kinetics following checkpoint activation by cisplatin and a platinum (IV) analog

Cisplatin interacts with its macromolecular target to form DNA cross-links, and this DNA damage activates cell cycle checkpoints to induce first a transient S-phase cell cycle arrest, which is followed by a durable G2/M arrest. In contrast, DNA damage by the analog DAP [1R,2R-diaminocyclohexane-(trans-diacetato)-(dichloro)-Pt(IV)] induces primarily a G1-arrest, with no appreciable arrest in S-phase or at G2/M. We have examined the underlying basis for these differences between the platinum drugs in ovarian A2780 tumor cells, which are equally responsive to the two drugs, as seen in comparable upregulation of the p53/p21 pathway beginning at about 6 h after drug treatment at the 5 x IC50 level. The differences in cell cycle arrests in S and G2/M were consistent with the onset of cisplatin-mediated inhibition of CDK2/cyclin A in S-phase at about 12 h and of Cdc2/cyclin B in G2-phase at about 12-18 h that were not observed with DAP. Inhibitions of these CDKs by cisplatin were not mediated by p21, but were ascribed to activating phosphorylations of Chk1 (at Ser-345) and Chk2 (at Thr-68), which were first detected at 6 h after drug treatment and increased progressively thereafter for the next 24 h. Activations of Chk1 and Chk2 would be expected to downregulate Cdc25 phosphatase activity and, thereby, maintain these CDKs in their inhibitory phosphorylated form. For direct evidence, levels of phospho-CDKs were assessed by immunoblot analysis, and shown to increase by 12 h after exposure of cells to cisplatin. As would be anticipated from a lack of S- or G2/M-arrest, Chk1 and Chk2 were not activated by DAP. As further support for independent effects of cisplatin and DAP on Chk1 and Chk2, knockdown of Chk1 or Chk2 by siRNA attenuated activation of the p53/p21 pathway with cisplatin, but not with DAP. With respect to G1-phase CDKs, the effects of the two drugs were surprisingly similar. Thus, both cisplatin and DAP potently inhibited CDK4/cycin D1 and CDK2/cyclin E activities in a p21-dependent manner at ∼18 h after drug treatment. This strongly suggests that the differential effect of the two drugs in arresting cells in G1-phase must be due to the earlier effects of cisplatin in S- and G2/M-phase. That is, cisplatin activates all three checkpoints, but the sequential response, first in S-phase and then robustly at G2/M, effectively blocks cells from progressing further and accumulating in G1. The results not only provide a mechanistic understanding for differential cell cycle kinetics induced by the two platinum drugs, but also serve to demonstrate that inhibition of G1-phase CDK is a more accurate index of G1 checkpoint response than is cell cycle arrest. (Supported by NCI RO1 CA127263).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3513.

Poly-GLP-1, a novel long-lasting glucagon-like peptide-1 polymer, ameliorates hyperglycaemia by improving insulin sensitivity and increasing pancreatic beta-cell proliferation

AIM

The clinical value of glucagon-like peptide-1 (GLP-1) is restricted because of its short half-life. To overcome this limitation, a new polymer of GLP-1 was developed by prodrug strategy, termed Poly-GLP-1, and its pharmacological properties were investigated.

METHODS

The in vitro release kinetics of GLP-1 from Poly-GLP-1 was analysed by Western blot. Plasma GLP-1 levels following a single administration of Poly-GLP-1 were determined by enzyme-linked immunosorbent assay. The in vitro effects of Poly-GLP-1 were evaluated using isolated pancreatic islets. The acute effects on glycaemic control and food intake were investigated in C57BL/6J mice s.c. administered with Poly-GLP-1. The chronic effects of Poly-GLP-1 on glycaemic control were further assessed in C57BL/6J and db/db mice treated twice daily for 6 weeks.

RESULTS

Pro-GLP-1 dose dependently increased insulin secretion and decreased glucose, but did not exhibit the insulinotropic action in isolated pancreatic islets without plasma. The glucose-lowering actions of Poly-GLP-1 (3 nmol/kg) remained no less than 12 h after a single injection. Poly-GLP-1 caused a durable restoration of glycaemic control, food intake and body weight gain in db/db mice following 6-week administration. The chronic treatment with Poly-GLP-1 improved glucose tolerance and insulin sensitivity and increased beta-cell mass and proliferation in db/db mice. There was little effect on normal mice treated in the same manner.

CONCLUSIONS

Our results indicated that Poly-GLP-1, a novel GLP-1 polymer, has long-lasting and potent effects on glycaemic control in vivo, and these beneficial effects may be because of improvement of insulin sensitivity and promotion of islet growth and function.

Protein kinase inhibitors emodin and dichloro-ribofuranosylbenzimidazole modulate the cellular accumulation and cytotoxicity of cisplatin in a schedule-dependent manner

PURPOSE

Protein kinase inhibitors (PKI) have become prominent agents in cancer therapeutics. However, the specificity for target kinase inhibition can be poor and unwanted effects can emerge in combination regimens. The PKI emodin, for instance, can produce mixed results when combined with cisplatin, and we have sought a biochemical pharmacologic explanation for the negative cytotoxic effects.

METHODS

Human ovarian A2780 tumor cells were exposed to the PKI emodin or dichloro-ribofuranosylbenzimidazole (DRB) with cisplatin using several schedules, and cytotoxicity determined by a growth inhibition assay. Intracellular platinum levels and DNA adducts were estimated by flameless atomic absorption spectrophotometry.

RESULTS

When A2780 cells were exposed first to emodin or DRB and then to cisplatin alone, the cytotoxic effects of cisplatin were significantly enhanced, whereas simultaneous exposure did not enhance the cytotoxicity, but instead inhibited it in the case of DRB. The increase in activity of cisplatin in the sequenced schedule was not due to increases in intracellular levels of cisplatin or DNA adducts, whereas the cytotoxic inhibition was related to a significant fall in both intracellular platinum levels and DNA adducts, which were ascribed to inhibition in cisplatin uptake. Knockdown of hCtr1 (the human copper transporter 1) by siRNA abrogated this inhibition in cisplatin uptake.

CONCLUSION

The results demonstrate that co-exposure of tumor cells to emodin or DRB with cisplatin inhibits platinum drug uptake by impacting the hCtr1 transporter and, thereby, reduce the cytotoxicity of cisplatin. Based on our findings, scheduling of the PKI and the cytotoxic agent should be a major consideration in the clinical design of combination regimens.

The first SSR-based genetic linkage map for cultivated groundnut (Arachis hypogaea L.)

Molecular markers and genetic linkage maps are pre-requisites for molecular breeding in any crop species. In case of peanut or groundnut (Arachis hypogaea L.), an amphidiploid (4X) species, not a single genetic map is, however, available based on a mapping population derived from cultivated genotypes. In order to develop a genetic linkage map for tetraploid cultivated groundnut, a total of 1,145 microsatellite or simple sequence repeat (SSR) markers available in public domain as well as unpublished markers from several sources were screened on two genotypes, TAG 24 and ICGV 86031 that are parents of a recombinant inbred line mapping population. As a result, 144 (12.6%) polymorphic markers were identified and these amplified a total of 150 loci. A total of 135 SSR loci could be mapped into 22 linkage groups (LGs). While six LGs had only two SSR loci, the other LGs contained 3 (LG_AhXV) to 15 (LG_AhVIII) loci. As the mapping population used for developing the genetic map segregates for drought tolerance traits, phenotyping data obtained for transpiration, transpiration efficiency, specific leaf area and SPAD chlorophyll meter reading (SCMR) for 2 years were analyzed together with genotyping data. Although, 2-5 QTLs for each trait mentioned above were identified, the phenotypic variation explained by these QTLs was in the range of 3.5-14.1%. In addition, alignment of two linkage groups (LGs) (LG_AhIII and LG_AhVI) of the developed genetic map was shown with available genetic maps of AA diploid genome of groundnut and Lotus and Medicago. The present study reports the construction of the first genetic map for cultivated groundnut and demonstrates its utility for molecular mapping of QTLs controlling drought tolerance related traits as well as establishing relationships with diploid AA genome of groundnut and model legume genome species. Therefore, the map should be useful for the community for a variety of applications.

Effect of dexamethasone on acute respiratory distress syndrome induced by the H5N1 virus in mice

Glucocorticoids are widely used in the treatment of different inflammatory diseases. The present study was performed to investigate the effect of dexamethasone (DEX) on acute respiratory distress syndrome (ARDS) induced by the H5N1 viral infection in mice. BALB/c mice, 6-8 weeks old, were divided into three groups with 80 mice in each. The infected group and the DEX-treated infected group were inoculated intranasally with 1 x 10(2) 50% mouse infectious dose of A/Chicken/Hebei/108/2002 (H5N1) viruses, with daily intraperitoneal injections of PBS, or 2.5 mg.kg(-1) DEX at days 3-14 post inoculation, respectively. The control group received noninfectious allantoic fluid and a daily intraperitoneal injection of PBS. In H5N1-infected mice, DEX treatment did not improve the mortality (17 out of 20 versus 16 out of 20 deaths in the DEX-treated infected group versus the infected group), and did not alleviate clinical signs, including weight loss, decreased food intake and inactivity. There was no significant amelioration of the hypoxaemia and ARDS-associated pathological changes in DEX-treated infected mice, as assessed by blood gas analysis and histological score. Furthermore, DEX therapy did not inhibit inflammatory cellular infiltration and cytokine release (interleukin-6 and tumour necrosis factor-alpha) in bronchoalveolar lavage fluid induced by the H5N1 infection. In conclusion, dexamethasone treatment (2.5 mg.kg(-1)) from days 3-14 post inoculation has no beneficial effect on acute respiratory distress syndrome caused by the H5N1 infection in mice.

Aldosterone and angiotensin II synergistically stimulate migration in vascular smooth muscle cells through c-Src-regulated redox-sensitive RhoA pathways

OBJECTIVE

Synergistic interactions between aldosterone (Aldo) and angiotensin II (Ang II) have been implicated in vascular inflammation, fibrosis, and remodeling. Molecular mechanisms underlying this are unclear. We tested the hypothesis that c-Src activation, through receptor tyrosine kinase transactivation, is critically involved in synergistic interactions between Aldo and Ang II and that it is upstream of promigratory signaling pathways in vascular smooth muscle cells (VSMCs).

METHODS AND RESULTS

VSMCs from WKY rats were studied. At low concentrations (10(-10) mol/L) Aldo and Ang II alone did not influence c-Src activation, whereas in combination they rapidly increased phosphorylation (P<0.01), an effect blocked by eplerenone (Aldo receptor antagonist) and irbesartan (AT1R blocker). This synergism was attenuated by AG1478 and AG1296 (inhibitors of EGFR and PDGFR, respectively), but not by AG1024 (IGFR inhibitor). Aldo and Ang II costimulation induced c-Src-dependent activation of NAD(P)H oxidase and c-Src-independent activation of ERK1/2 (P<0.05), without effect on ERK5, p38MAPK, or JNK. Aldo/Ang II synergistically activated RhoA/Rho kinase and VSMC migration, effects blocked by PP2, apocynin, and fasudil, inhibitors of c-Src, NADPH oxidase, and Rho kinase, respectively.

CONCLUSIONS

Aldo/Ang II synergistically activate c-Src, an immediate signaling response, through EGFR and PDGFR, but not IGFR transactivation. This is associated with activation of redox-regulated RhoA/Rho kinase, which controls VSMC migration. Although Aldo and Ang II interact to stimulate ERK1/2, such effects are c-Src-independent. These findings indicate differential signaling in Aldo-Ang II crosstalk and highlight the importance of c-Src in redox-sensitive RhoA, but not ERK1/2 signaling. Blockade of Aldo/Ang II may be therapeutically useful in vascular remodeling associated with abnormal VSMC migration.

Topology preserving non-negative matrix factorization for face recognition

In this paper, a novel topology preserving non-negative matrix factorization (TPNMF) method is proposed for face recognition. We derive the TPNMF model from original NMF algorithm by preserving local topology structure. The TPNMF is based on minimizing the constraint gradient distance in the high-dimensional space. Compared with L(2) distance, the gradient distance is able to reveal latent manifold structure of face patterns. By using TPNMF decomposition, the high-dimensional face space is transformed into a local topology preserving subspace for face recognition. In comparison with PCA, LDA, and original NMF, which search only the Euclidean structure of face space, the proposed TPNMF finds an embedding that preserves local topology information, such as edges and texture. Theoretical analysis and derivation given also validate the property of TPNMF. Experimental results on three different databases, containing more than 12,000 face images under varying in lighting, facial expression, and pose, show that the proposed TPNMF approach provides a better representation of face patterns and achieves higher recognition rates than NMF.

Household CO and PM measured as part of a review of China's National Improved Stove Program

In 2001-2003, a team of researchers from the United States and China performed an independent, multidisciplinary review of China's National Improved Stove Program carried out since the 1980s. As part of a 3500-household survey, a subsample of 396 rural households were monitored for particulate matter less than 4 microm (PM(4)) in kitchens and living rooms over 24 h, of which 159 were measured in both summer and winter. Carbon monoxide was measured in a 40% subsample. The results of this indoor air quality (IAQ) component indicate that for nearly all household stove or fuel groupings, PM(4) levels were higher than - and sometimes more than twice as high as - the national PM(10) standard for indoor air (150 microg PM(10)/m(3)). If these results are typical, then a large fraction of China's rural population is now chronically exposed to levels of pollution far higher than those determined by the Chinese government to harm human health. Further, we observed highly diverse fuel usage patterns in these regions in China, supporting the observations in the household survey of multiple stoves being present in many kitchens. Improved stoves resulted in reduced PM(4) from biomass fuel combinations, but still not at levels that meet standards, and little improvement was observed in indoor pollution levels when other unimproved stoves were present in the same kitchen. As many households change fuels according to daily and seasonal factors, resulting in different seasonal concentrations in living rooms and kitchens, assessing health implications from fuel use requires longitudinal evaluation of fuel use and IAQ levels, combined with accurate time-activity information.

PRACTICAL IMPLICATIONS

Leaving aside the difficult issue of enforcement, it is uncertain whether Chinese household IAQ standards represent realistic objectives for current attainment given current patterns of energy consumption in rural China, which rely so heavily on unprocessed solid fuels. Even when used with chimneys, these fuels emit substantial pollution into the household environment. It is probable that low-emission technologies involving gaseous/liquid fuels or high combustion - efficiency biomass stoves need to be promoted in order to achieve these standards for the greater part of the population.

NEDD4-1 is a proto-oncogenic ubiquitin ligase for PTEN

The tumor suppressor PTEN, a critical regulator for multiple cellular processes, is mutated or deleted frequently in various human cancers. Subtle reductions in PTEN expression levels have profound impacts on carcinogenesis. Here we show that PTEN level is regulated by ubiquitin-mediated proteasomal degradation, and purified its ubiquitin ligase as HECT-domain protein NEDD4-1. In cells NEDD4-1 negatively regulates PTEN stability by catalyzing PTEN polyubiquitination. Consistent with the tumor-suppressive role of PTEN, overexpression of NEDD4-1 potentiated cellular transformation. Strikingly, in a mouse cancer model and multiple human cancer samples where the genetic background of PTEN was normal but its protein levels were low, NEDD4-1 was highly expressed, suggesting that aberrant upregulation of NEDD4-1 can posttranslationally suppress PTEN in cancers. Elimination of NEDD4-1 expression inhibited xenotransplanted tumor growth in a PTEN-dependent manner. Therefore, NEDD4-1 is a potential proto-oncogene that negatively regulates PTEN via ubiquitination, a paradigm analogous to that of Mdm2 and p53.

Upregulation of p27 and its inhibition of CDK2/cyclin E activity following DNA damage by a novel platinum agent are dependent on the expression of p21

The cisplatin analogue 1R,2R-diaminocyclohexane(trans-diacetato)(dichloro)platinum^IV (DAP) is a DNA-damaging agent that will be entering clinical trials for its potent cytotoxic effects against cisplatin-resistant tumour cells. This cytotoxicity may reside in its ability to selectively activate G1-phase checkpoint response by inhibiting CDKs via the p53/p21 pathway. We have now evaluated the role of another CDK inhibitor p27 as a contributor to DAP-mediated inhibition of G1-phase CDK2 activity. Our studies in ovarian A2780 tumour cells demonstrate that p27 levels induced by DAP are comparable to or greater than those seen for p21. The induction of p27 is not through a transcriptional mechanism, but rather is due to a four-fold increase in protein stabilisation through a mechanism dependent on p21. Moreover, DAP-induced p21 promoted the selective increase of p27 in the CDK2 complex, but not in CDK4 complex, and this selective increase contributed to inhibition of the CDK2 kinase activity. The inhibited complex contained either p27 or p21, but not both, with the relative levels of cyclin E associated with p27 and p21 indicating that about 25% of the inhibition of CDK2 activity was due to p27 and 75% due to p21. This study provides the first evidence that p27 upregulation is directly attributable to activation of the p53/p21 pathway by a DNA-damaging agent, and promulgates p53/p21/p27 axis as a significant component of checkpoint response.

Involvement of the conserved adaptor protein Alix in actin cytoskeleton assembly

The conserved adaptor protein Alix, also called AIP1 or Hp95, promotes flattening and alignment of cultured mammalian fibroblasts; however, the mechanism by which Alix regulates fibroblast morphology is not understood. Here we demonstrate that Alix in WI38 cells, which require Alix expression for maintaining typical fibroblast morphology, associates with filamentous actin (F-actin) and F-actin-based structures lamellipodia and stress fibers. Reducing Alix expression by small interfering RNA (siRNA) decreases F-actin content and inhibits stress fiber assembly. In cell-free systems, Alix directly interacts with F-actin at both the N-terminal Bro1 domain and the C-terminal proline-rich domain. In Alix immunoprecipitates from WI38 cell lysates, actin is the most abundant partner protein of Alix. In addition, the N-terminal half of the middle region of Alix binds cortactin, an activator of the ARP2/3 complex-mediated initiation of actin polymerization. Alix is required for lamellipodial localization of cortactin. The C-terminal half of the middle region of Alix interacts with alpha-actinin, a key factor that bundles F-actin in stress fibers. Alix knockdown decreases the amount of alpha-actinin that associates with F-actin. These findings establish crucial involvement of Alix in actin cytoskeleton assembly.

Association of TPH1 with suicidal behaviour and psychiatric disorders in the Chinese population

Tryptophan hydroxylase (TPH), the rate limiting enzyme in serotonin biosynthesis, is one of the most important regulating factors in the serotonergic system. Recently, polymorphisms of the TPH gene have been identified as being associated with suicide, but the evidence is inconsistent. To investigate the role in suicide of one of the isoforms, TPH1, we examined the association of five single nucleotide polymorphisms (SNPs) in the promoter region and in intron 7 of the TPH1 gene based on a sample from the Chinese population of 810 subjects, of whom 329 had made no suicide attempts (NSA), 297 had made suicide attempts (SA), and 184 were healthy subjects (HS). In this study, we observed statistically significant differences between NSA and HS subjects in allele distributions on one marker, -6526A (p = 0.0329; odds ratio (OR) 1.36; 95% confidence interval (CI) 1.01 to 1.81). No significant difference in genotype distribution or allele frequencies of other polymorphisms was found between the suicide victims and the controls. The overall haplotype frequency was significantly different between cases and healthy controls (p = 0.000024 NSA v HS; p < 0.000001, SA v HS; p < 0.000001, cases v HS). We found the haplotype TCAAA of -7180/-7065/-6526/218/779 to be strongly associated with suicidal behaviour and psychiatric disorders (p = 0.00243; OR = 1.62; 95% CI 1.17 to 2.24 and p = 0.018; OR = 1.41; 95% CI 1.05 to 1.91), which suggests an association of TPH1 with suicidal behaviour and indicates that TPH1 may play a significant role in the aetiology of psychiatric disorders in the Han Chinese population.

MPZL1/PZR, a novel candidate predisposing schizophrenia in Han Chinese

The MPZL1/PZR gene has been mapped to 1q23.3, located in close proximity to a recognized schizophrenia susceptibility locus. Recently, the MPZL1/PZR gene has been found to be significantly upregulated in schizophrenia brain tissue and to play an important role in cell signaling, thus indicating that MPZL1/PZR could be a potential schizophrenia marker. To test this hypothesis, we selected three single nucleotide polymorphisms (SNPs) for genotyping in 523 Han Chinese trios. We found that two individual SNPs were significant at the Bonferroni's corrected significance level P<0.017: rs3767444 (chi2=6.299, P=0.0121) and rs2051656 (chi2=9.856, P=0.0017). Haplotype transmission/disequilibrium tests revealed a significant association with the disease (global P-value=1.064 x 10(-6)), but no specific transmission distortions. Thus, we propose that the MPZL1/PZR gene may be important in the predisposition to schizophrenia among Han Chinese.