COAP-Pd Catalyzed Asymmetric Formal [3+2] Cycloaddition for Optically Active Multistereogenic Spiro Cyclopentane-Indandiones Bearing Cyclic N-Sulfonyl Ketimine Skeletons.

We reported a chiral oxamide-phosphine ligand (COAP-Ph)-Pd-catalyzed asymmetric [3+2] cycloaddition reaction between vinyl cyclopropane compounds derived from 1,3-indanedione and 2-vinylcyclopropane-1,1-dicarboxylates with cyclic sulfonyl 1-azadienes. The corresponding reactions provided a series of enantiomerically active spiro cyclopentane-indandione and cyclopentane structures bearing three consecutive stereogenic centers in good yields with good diastereo- and enantioselectivity. The COAP-Pd complex serves not only to promote generation of chiral π-allyl-palladium intermediates and induce the asymmetry of the reaction, but also depress the background reaction.

Genome assembly of autotetraploid Actinidia arguta highlights adaptive evolution and enables dissection of important economic traits.

Actinidia arguta, the most widely distributed Actinidia species and the second cultivated species in the genus, can be distinguished from the currently cultivated Actinidia chinensis on the basis of its small and smooth fruit, rapid softening, and excellent cold tolerance. Adaptive evolution of tetraploid Actinidia species and the genetic basis of their important agronomic traits are still unclear. Here, we generated a chromosome-scale genome assembly of an autotetraploid male A. arguta accession. The genome assembly was 2.77 Gb in length with a contig N50 of 9.97 Mb and was anchored onto 116 pseudo-chromosomes. Resequencing and clustering of 101 geographically representative accessions showed that they could be divided into two geographic groups, Southern and Northern, which first diverged 12.9 million years ago. A. arguta underwent two prominent expansions and one demographic bottleneck from the mid-Pleistocene climate transition to the late Pleistocene. Population genomics studies using paleoclimate data enabled us to discern the evolution of the species' adaptation to different historical environments. Three genes (AaCEL1, AaPME1, and AaDOF1) related to flesh softening were identified by multi-omics analysis, and their ability to accelerate flesh softening was verified through transient expression assays. A set of genes that characteristically regulate sexual dimorphism located on the sex chromosome (Chr3) or autosomal chromosomes showed biased expression during stamen or carpel development. This chromosome-level assembly of the autotetraploid A. arguta genome and the genes related to important agronomic traits will facilitate future functional genomics research and improvement of A. arguta.

Chiral Phosphine Ligands of COAP and SKP Switched Regiodivergent Asymmetric Allylic Alkylation of MBH Adducts.

The palladium-catalyzed highly regioselective asymmetric allylic alkylation of 3'-indolyl-3-oxindole derivatives with Morita-Baylis-Hillman (MBH) carbonates was developed to facilely construct chiral 3,3'-bisindole derivatives under mild reaction conditions. The regioselectivity (α/γ) of MBH carbonates was efficiently switched in the presence of chiral oxalamide phosphine or spiroketal-based diphosphine/Pd(0) complexes as a chiral catalyst. A series of multifunctional 3,3'-bisindole derivatives with all-carbon quaternary stereogenic centers were obtained in high yields with good to excellent enantio-, diastereo-, and regioselectivity. The present process is endowed with some salient features such as broad substrate scope, N-protecting group-free, excellent stereoselectivity, as well as adjustable regioselectivity.

Identification of a cuproptosis and copper metabolism gene-related lncRNAs prognostic signature associated with clinical and immunological characteristics of hepatocellular carcinoma.

Background: The relationship between cuproptosis and HCC is still in the exploratory stage. Long noncoding RNAs (lncRNAs) have recently been linked to the progression of hepatocellular carcinoma (HCC). However, the clinical significance of lncRNAs associated with cuproptosis remains unclear. Methods: Based on The Cancer Genome Atlas (TCGA) liver hepatocellular carcinoma (LIHC) dataset, we identified characteristic prognostic lncRNAs by univariate, LASSO, and multifactorial regression analysis, and constructed a prognostic signature of cuproptosis-related lncRNAs in HCC. The role of lncRNAs were identified through CCK-8, clone formation in Huh-7 cells with high expression of FDX1. Prognostic potential of the characteristic lncRNAs was evaluated in each of the two cohorts created by randomly dividing the TCGA cohort into a training cohort and a test cohort in a 1:1 ratio. Immune profiles in defined subgroups of cuproptosis-related lncRNA features as well as drug sensitivity were analyzed. Results: We constructed a multigene signature based on four characteristic prognostic lncRNAs (AL590705.3, LINC02870, KDM4A-AS1, MKLN1-AS). These four lncRNAs participated in the development of cuproptosis. HCC patients were classified into high-risk and low-risk groups based on the median value of the risk score. The receiver operating characteristic curve area under the curve values for 1-, 3-, and 5-year survival were 0.773, 0.728, and 0.647, respectively, for the training cohort, and 0.764, 0.671, and 0.662, respectively, for the test cohort. Univariate and multifactorial regression analyses indicated that this prognostic feature was an independent prognostic factor for HCC. Principal component analysis plots clearly distinguished between low- and high-risk patients in terms of their probability of survival. Furthermore, gene set enrichment analysis showed that a variety of processes associated with tumor proliferation and progression were enriched in the high-risk group compared with the low-risk group. Moreover, there were significant differences in the expression of immune cell subpopulations, immune checkpoint genes, and potential drug screening, which provided distinct therapeutic recommendations for individuals with various risks. Conclusions: We constructed a novel cuproptosis-associated lncRNA signature with a significant predictive value for the prognosis of patients with HCC. Cuproptosis-associated lncRNAs are associated with the tumor immune microenvironment of HCC and even the efficacy of tumor immunotherapy.

COAP/Pd-Catalyzed Linear Asymmetric Allylic Alkylation for Optically Active 3,3-Disubstituted Oxindole Derivatives with a Four-Carbon Amino Side Chain.

An asymmetric linear selective allylic alkylation of vinylaziridines with 3-aryl oxindoles has been developed by using a chiral oxamide-phosphine (COAP-Bn-OMe-p)/palladium complex in methanol, which furnished a wide variety of 3,3-disubstituted oxindole derivatives in good yields with excellent regio- and enantioselectivities.

Research progress of lncRNA and miRNA in hepatic ischemia-reperfusion injury.

BACKGROUND: Hepatic ischemia-reperfusion injury (HIRI) is a common complication of liver surgeries, such as hepatectomy and liver transplantation. In recent years, several non-coding RNAs (ncRNAs) including long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been identified as factors involved in the pathological progression of HIRI. In this review, we summarized the latest research on lncRNAs, miRNAs and the lncRNA-miRNA regulatory networks in HIRI. DATA SOURCES: The PubMed and Web of Science databases were searched for articles published up to December 2021 using the following keywords: "hepatic ischemia-reperfusion injury", "lncRNA", "long non-coding RNA", "miRNA" and "microRNA". The bibliography of the selected articles was manually screened to identify additional studies. RESULTS: The mechanism of HIRI is complex, and involves multiple lncRNAs and miRNAs. The roles of lncRNAs such as AK139328, CCAT1, MALAT1, TUG1 and NEAT1 have been established in HIRI. In addition, numerous miRNAs are associated with apoptosis, autophagy, oxidative stress and cellular inflammation that accompany HIRI pathogenesis. Based on the literature, we conclude that four lncRNA-miRNA regulatory networks mediate the pathological progression of HIRI. Furthermore, the expression levels of some lncRNAs and miRNAs undergo significant changes during the progression of HIRI, and thus are potential prognostic markers and therapeutic targets. CONCLUSIONS: Complex lncRNA-miRNA-mRNA networks regulate HIRI progression through mutual activation and antagonism. It is necessary to screen for more HIRI-associated lncRNAs and miRNAs in order to identify novel therapeutic targets.

Box-copper catalyzed cascade asymmetric amidation for chiral exo-methylene aminoindoline derivatives.

Enantioselective copper-catalyzed cascade inter- and intramolecular amidation was achieved between ethynyl benzoxazinanones and α-halohydroxamates in the presence of an indapybox ligand. The one-pot cascade transformation was triggered by the attack of hydroxamates to dipolar copper-allenylidene intermediates, followed by a nucleophilic annulation reaction. Thus, a series of exo-methylene 3-aminoindoline derivatives were obtained in good yields with high enantioselectivities under mild reaction conditions.

Optimal adjuvant chemotherapy completion time for stage III colon cancer: a cohort study.

BACKGROUND: Adjuvant chemotherapy for 6 months following surgery is the standard treatment plan for stage III colon cancer. The aim of the present study was to determine whether the adjuvant chemotherapy completion time for stage III colon cancer had an effect on prognosis and cut-off time that affected the prognosis. METHODS: This was a retrospective study of stage III colon cancer patients who completed adjuvant chemotherapy at Guangzhou Red Cross Hospital from January 2010 to December 2017. Univariate and multivariate analyses were used to determine the association between adjuvant chemotherapy completion time and the 3-year disease-free survival (DFS). The restricted cubic spline model was used to analyze the cut-off time that affected the 3-year DFS. RESULTS: A total of 431 patients were included in the study. The 3-year DFS was associated with a combination of obstruction or perforation, preoperative serum carcino-embryonic antigen (CEA) concentration, T stage, N stage, pathological stage, and adjuvant chemotherapy completion time in the univariate analysis (P<0.05). A combination of obstruction or perforation, preoperative serum CEA concentration, N stage, and adjuvant chemotherapy completion time were independent prognostic factors in the multivariate analysis (P<0.05). The cut-off time was 28 weeks for adjuvant chemotherapy completion time in the restricted cubic spline model analysis. For those whose adjuvant chemotherapy completion time was >28 weeks, the risk of 3-year recurrence was 1.428 times higher compared with those whose adjuvant chemotherapy completion time was ≤28 weeks. [P=0.032, 95% confidence interval (CI): 1.034-2.055]. CONCLUSIONS: The 3-year DFS of stage III colon cancer was related to the adjuvant chemotherapy completion time. For those who completed adjuvant chemotherapy >28 weeks, the risk of 3-year recurrence increased.

Chiral Bidentate Phosphoramidite-Pd Catalyzed Asymmetric Decarboxylative Dipolar Cycloaddition for Multistereogenic Tetrahydrofurans with Cyclic N-Sulfonyl Ketimine Moieties.

An asymmetric [3 + 2] cycloaddition of vinyl ethylenecarbonates (VECs) and (E)-3-arylvinyl substituted benzo[d] isothiazole 1,1-dioxides has been developed using the Pd complex of a bidentate phosphoramidite (Me-BIPAM) as the catalyst, providing a wide variety of chiral multistereogenic vinyltetrahydrofurans in good yields with excellent diastereo- and enantioselectivities (up to >20:1 dr, 99% ee).

Down-regulation of EGFL8 regulates migration, invasion and apoptosis of hepatocellular carcinoma through activating Notch signaling pathway.

BACKGROUND: Our previous studies have reported the down-regulation of EGFL8 correlates to the development and prognosis of colorectal and gastric cancer. The present study is carried out to explore the expression pattern and role of EGFL8 in hepatocellular carcinoma (HCC). METHODS AND MATERIALS: EGFL8 expression in 102 cases of HCC tissues matched with adjacent non-tumorous liver tissues, a normal liver cell line and three liver cancer cell lines with different metastatic capacity was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot. Moreover, the clinicopathological features and prognosis of HCC patients were correlated with expression of EGFL8. Subsequently, the gain-and loss-of-function experiments were carried out to investigate the biological function of EGFL8 in HCC. We also used N-[N-(3,5-Difluorophenacetyl-L-alanyl)]-(S)- phenylglycine t-butyl ester (DAPT), an inhibitor for Notch signaling pathway, in these experiments to verify the involvement of Notch signaling pathway in the effects of EGFL8. Additionally, a mouse model was established to investigate the effect of EGFL8 on metastasis of HCC cells. The expression of Notch signaling pathway in HCC cells and xenograft mouse tumors were detected by Western blot and immunohistochemistory. RESULTS: The expression of EGFL8 was significantly decreased in HCC tissues and cell lines and EGFL8 down-regulation correlated to multiple nodules, vein invasion, high TNM stage and poor prognosis of HCC. Interestingly, the expression levels of EGFL8 in three liver cancer cell lines were negatively associated with their metastatic capacity. In vitro and in vivo experiments indicated that EGFL8 obviously suppressed metastasis and invasion of HCC cells but slightly promoted apoptosis. Meanwhile, the expression of Notch signaling pathway was obviously suppressed in EGFL8 overexpressed HCCLM3 cells and xenograft mouse tumors generated from these cells but markedly elevated in EGFL8 depleted Hep3B cells. Furthermore, the up-regulated expression of Notch signaling pathway and effects induced by EGFL8 knockdown in Hep3B cells could be counteracted by DAPT treatment. CONCLUSION: The down-regulation of EGFL8 was correlated to progression and poor prognosis of HCC and regulates HCC cell migration, invasion and apoptosis through activating the Notch signaling pathway, suggesting EGFL8 as a novel therapeutic target and a potential prognostic marker for HCC.

ELK1-induced upregulation of lncRNA TRPM2-AS promotes tumor progression in gastric cancer by regulating miR-195/ HMGA1 axis.

Long noncoding RNAs (lncRNAs) have been confirmed to be aberrantly expressed in various diseases including tumors. Recently, a new tumor-related lncRNA, lncRNA TRPM2 antisense RNA (TRPM2-AS), was shown to be involved in many tumors, such as lung cancer and breast cancer. However, the expression and role of TRPM2-AS in the development of gastric cancer (GC) have not been elucidated. In the current study, we provided evidence that the expression levels of TRPM2-AS were increased in both GC tissues and cell lines. We also showed that overexpression of TRPM2-AS was modulated by ELK1, a transcription factor. The results of clinical assays showed that higher expressions of TRPM2-AS were significantly related with invasion depth, TNM stage, lymphatic metastasis, and shorter overall survival. Further clinical assays using multivariate analysis suggested that TRPM2-AS expression was an independent prognostic factor in patients with GC. Functional experiments illustrated that depression of TRPM2-AS suppressed proliferation, migration, and invasion in GC cells. In terms of mechanism, we found that TRPM2-AS directly inhibited miR-195, which targeted the 3'-untranslated region of high-mobility group AT-hook 1 (HMGA1) messenger RNA. Overall, these findings revealed that ELK1-induced overexpression of TRPM2-AS promoted the development and progression of GC in part through miR-195/HMGA1 signaling axis, and established its candidacy as a new cancer biomarker for GC patients.

Upregulation of WEE1 is a potential prognostic biomarker for patients with colorectal cancer.

WEE1 is a serine/threonine protein kinase that inactivates cell division cycle 2 and is therefore a critical cell cycle regulator. Increased WEE1 expression has been observed in numerous types of human malignancies, including hepatocellular carcinoma and melanoma. WEE1 inhibition also results in evident anti-tumor effects in several human tumor cells including colon cancer cells, suggesting WEE1 as a potential therapeutic target for the treatment of cancer. However, the expression pattern of WEE1 in colorectal cancer (CRC) remains unclear. In the present study, WEE1 mRNA expression in 43 cases of CRC tissues matched with adjacent normal tissues was determined by reverse-transcription quantitative polymerase chain reaction. The results demonstrated that WEE1 mRNA expression was significantly increased in CRC tissues and that this upregulation correlated significantly with hepatic metastasis, distant metastasis and high tumor node metastasis (TNM) stage of CRC. Additionally, WEE1 protein in 102 CRC tissue samples was detected by immunohistochemistry, and positive staining of WEE1 was identified in more than half of patients with CRC. WEE1 staining scores were also observed to be associated with distant metastasis and high TNM stage of CRC. In addition, patients with CRC with high WEE1 staining score (2+ or 3+) exhibited either poorer overall survival or poorer disease-free survival compared with those with low WEE1 staining score (0 or 1+). The multivariable Cox model also identified a high WEE1 staining score as well as high TNM stage to be independent prognostic factors for CRC. In conclusion, WEE1 upregulation is associated with a high degree of malignancy and poor prognosis of CRC, suggesting WEE1 as a potential prognostic biomarker for CRC.

Mus81 knockdown sensitizes colon cancer cells to chemotherapeutic drugs by activating CHK1 pathway.

PURPOSE: The inhibition of Mus81, a critical DNA repair gene, is recently related to the chemosensitivity of several human cancer cells such as hepatocellular carcinoma (HCC) cells. However, the role of Mus81 knockdown in chemotherapy response of colon cancer cells remains largely unknown. METHODS AND MATERIALS: The effects of Mus81 knockdown by lentivirus-mediated short hairpin RNA in sensitivity of HCT116 and LS180 colon cancer cell lines to four therapeutic drugs, including cisplatin (CDDP), were evaluated by MTT assay as well as a mouse model. Apoptosis and cell cycle distribution of HCT116 cell line was detected by flow cytometric analysis. Western blot was also employed to determine the expression of CHK1 pathway and apoptosis-related proteins in HCT116 cells and the xenograft mouse tumors. RESULTS: Mus81 knockdown could significantly improve the chemosensitivity of colon cancer cells in vitro and in vivo, especially to CDDP. Mus81 knockdown also induced S phase arrest and elevated apoptosis in CDDP treated HCT116 cells through activating CHK1/CDC25A/CDK2 and CHK1/p53/Bax pathways, while these effects could be counteracted by CHK1 inhibition. CONCLUSION: Mus81 knockdown improves the chemosensitivity of colon cancer cells by inducing S phase arrest and promoting apoptosis through activating CHK1 pathway.

STC2 as a novel mediator for Mus81-dependent proliferation and survival in hepatocellular carcinoma.

Methyl methansulfonate and UV sensitive gene clone 81 (Mus81) is a critical DNA repair gene that has been implicated in development of several cancers including hepatocellular carcinoma (HCC). However, whether Mus81 can affect proliferation and survival of HCC remains unknown. In the present study, we demonstrated that the knockdown of Mus81 was associated with suppressed proliferation and elevated apoptosis of HCC cells in vitro and in vivo. Multilayered screenings, including DNA microarray, high content screen, and real-time PCR validation, identified STC2 as a proliferation-facilitating gene significantly down-regulated in HCC cells upon Mus81 knockdown. STC2 expression was also closely correlated to Mus81 expression in HCC tissues. More importantly, the restoration of STC2 expression recovered the compromised cell proliferation and survival in Mus81 depleted HCC cells. Furthermore, Mus81 knockdown was associated with the activation of APAF1, APC, and PTEN pathways and concurrent inhibition of MAPK pathway through decreasing STC2 expression. In conclusion, Mus81 knockdown suppresses proliferation and survival of HCC cells likely by downregulating STC2 expression, implicating Mus81 as a therapeutic target for HCC.

Mus81 knockdown improves chemosensitivity of hepatocellular carcinoma cells by inducing S-phase arrest and promoting apoptosis through CHK1 pathway.

As a critical endonuclease in DNA repair, Mus81 is traditionally regarded as a tumor suppressor, but recently correlated with the sensitivity of mitomycin C and 5-fluorouracil in colon cancer and breast cancer cells. However, its role in chemosensitivity of other human malignancies still remains unknown. This study therefore aims to investigate the effects of Mus81 knockdown on the chemosensitivity of hepatocellular carcinoma (HCC), a usually chemorefractory tumor, and explore the underlying mechanisms. Mus81 expression in HepG2 and Bel-7402 HCC cell lines was depleted by lentivirus-mediated short hairpin RNA and the elevated sensitivity of these Mus81-inhibited HCC cells to therapeutic agents, especially to epirubicin (EPI), was evidenced by MTT assay and an HCC chemotherapy mouse model. Flow cytometric analysis also showed that Mus81 knockdown lead to an obvious S-phase arrest and an elevated apoptosis in EPI-treated HepG2 and Bel-7402 cells, which could be rescued by CHK1 inhibition. The activation of CHK1/CDC25A/CDK2 pathway was also demonstrated in Mus81-inhibited HepG2 cells and xenograft mouse tumors under EPI treatment. Meanwhile, the apoptosis of HepG2 cells in response to EPI was remarkably promoted by Mus81 knockdown through activating p53/Bax/Caspase-3 pathway under the controlling of CHK1. In addition, CHK2 inhibition slightly raised CHK1 activity, thereby enhancing the S-phase arrest and apoptosis induced by EPI in Mus81-suppressed HCC cells. In conclusion, Mus81 knockdown improves the chemosensitivity of HCC cells by inducing S-phase arrest and promoting apoptosis through CHK1 pathway, suggesting Mus81 as a novel therapeutic target for HCC.

Identification of the substrate recognition region in the Δ6-fatty acid and Δ8-sphingolipid desaturase by fusion mutagenesis.

Δ8-sphingolipid desaturase and Δ6-fatty acid desaturase share high protein sequence identity. Thus, it has been hypothesized that Δ6-fatty acid desaturase is derived from Δ8-sphingolipid desaturase; however, there is no direct proof. The substrate recognition regions of Δ6-fatty acid desaturase and Δ8-sphingolipid desaturase, which aid in understanding the evolution of these two enzymes, have not been reported. A blackcurrant Δ6-fatty acid desaturase and a Δ8-sphingolipid desaturase gene, RnD6C and RnD8A, respectively, share more than 80 % identity in their coding protein sequences. In this study, a set of fusion genes of RnD6C and RnD8A were constructed and expressed in yeast. The Δ6- and Δ8-desaturase activities of the fusion proteins were characterized. Our results indicated that (1) the exchange of the C-terminal 172 amino acid residues can lead to a significant decrease in both desaturase activities; (2) amino acid residues 114-174, 206-257, and 258-276 played important roles in Δ6-substrate recognition, and the last two regions were crucial for Δ8-substrate recognition; and (3) amino acid residues 114-276 of Δ6-fatty acid desaturase contained the substrate recognition site(s) responsible for discrimination between ceramide (a substrate of Δ8-sphingolipid desaturase) and acyl-PC (a substrate of Δ6-fatty acid desaturase). Substituting the amino acid residues 114-276 of RnD8A with those of RnD6C resulted in a gain of Δ6-desaturase activity in the fusion protein but a loss in Δ8-sphingolipid desaturase activity. In conclusion, several regions important for the substrate recognition of Δ8-sphingolipid desaturase and Δ6-fatty acid desaturase were identified, which provide clues in understanding the relationship between the structure and function in desaturases.

The role of C-terminal amino acid residues of a Δ6-fatty acid desaturase from blackcurrant.

Δ6-fatty acid desaturase is an important enzyme in the catalytic synthesis of polyunsaturated fatty acids. Using domain swapping and a site-directed mutagenesis strategy, we found that the region of the C-terminal 67 amino acid residues of Δ6-fatty acid desaturase RnD6C from blackcurrant was essential for its catalytic activity and that seven different residues between RnD6C and RnD8A in that region were involved in the desaturase activity. Compared with RnD6C, the activity of the following mutations, V394A, K395I, F411L, S436P, VK3945AI and IS4356VP, was significantly decreased, whereas the activity of I417T was significantly increased. The amino acids N, T and Y in the last four residues also play a certain role in the desaturase activity.

Identification and functional analysis of the genes encoding Delta6-desaturase from Ribes nigrum.

Gamma-linolenic acid (gamma-linolenic acid, GLA; C18:3 Delta(6, 9, 12)) belongs to the omega-6 family and exists primarily in several plant oils, such as evening primrose oil, blackcurrant oil, and borage oil. Delta(6)-desaturase is a key enzyme involved in the synthesis of GLA. There have been no previous reports on the genes encoding Delta(6)-desaturase in blackcurrant (Ribes nigrum L.). In this research, five nearly identical copies of Delta(6)-desaturase gene-like sequences, named RnD8A, RnD8B, RnD6C, RnD6D, and RnD6E, were isolated from blackcurrant. Heterologous expression in Saccharomyces cerevisiae and/or Arabidopsis thaliana confirmed that RnD6C/D/E were Delta(6)-desaturases that could use both alpha-linolenic acids (ALA; C18:3 Delta(9,12,15)) and linoleic acid (LA; C18:2 Delta(9,12)) precursors in vivo, whereas RnD8A/B were Delta(8)-sphingolipid desaturases. Expression of GFP tagged with RnD6C/D/E showed that blackcurrant Delta(6)-desaturases were located in the mitochondrion (MIT) in yeast and the endoplasmic reticulum (ER) in tobacco. GC-MS results showed that blackcurrant accumulated GLA and octadecatetraenoic acids (OTA; C18:4 Delta(6,9,12,15)) mainly in seeds and a little in other organs and tissues. RT-PCR results showed that RnD6C and RnD6E were expressed in all the tissues at a low level, whereas RnD6D was expressed at a high level only in seeds, leading to the accumulation of GLA and OTA in seeds. This research provides new insights to our understanding of GLA synthesis and accumulation in plants and the evolutionary relationship of this class of desaturases, and new clues as to the amino acid determinants which define precise enzyme activity.

Clinical relationship between MDR1 gene and gallbladder cancer.

BACKGROUND: The most common mechanisms of multidrug resistance (MDR) in cancer cells is the expression of an energy-dependent exfflux pump. P-glycoprotein (P-gp) encoded by MDR1 gene and multidrug associated protein (MRP) are well known proteins associated with MDR. In human cancers, the MDR1 gene expression is common in patients with intrinsic and acquired MDR. It is a major therapeutic problem in cancer chemotherapy. Previously we found that the MDR of HCC is related to MRP gene expression and initiates the intrinsic MDR. The aim of this study is to study the expression of MDR1 gene encoding P-gp and MDRl mRNA in primary gallbladder carcinoma, and analyze its clinical significance. METHODS: Immunohistochemistry (IHC) S-P method and in situ polymerase chain reaction (ISPCR) were used to detect the expression of P-gp and MDR1 mRNA in 53 cases of untreated primary gallbladder carcinoma and 12 cases of cholecystitis (archival paraffin-embedded tissues). RESULTS: The positive expression rates of P-gp and MDR1 mRNA in the 53 cases and 12 cases were 60.38%, 71.69% and 25.00%, 33.33%, respectively. There was a significant difference between the two groups (P<0.05). The positive expression rate of P-gp and MDR1mRNA were 69.44%, 83.33% and 41.18%, 47.06% respectively in tissues in stage of Nevin I-III against Nevin IV, V (P<0.05). In well, moderately differentiated gallbladder carcinoma tissues, their expressions were 79.49%, 69.23% against 50.00%, 35.71% in low, undifferentiated tissues (P<0.05). CONCLUSIONS: MDR to gallbladder carcinoma is closely related to the intrinsic MDR and it provides an important evidence to reverse the MDR by detection of the MDR1 gene. Meanwhile, MDR1 gene expression in gallbladder carcinoma is correlated with some biological characteristics, takes part in the carcinogenesis of gallbladder tissues, and acts as a valuable biomarker of prognosis.

Clinical significance of mrp gene in primary hepatocellular carcinoma.

OBJECTIVE: To study the relations among the expression of the multidrug resistance associated-protein (mrp) gene and clinicopathologic features, the influence of alpha-fetoprotein (AFP), and prognosis of patients who received adjuvant chemotherapy after resection of primary hepatocellular carcinoma (HCC). METHODS: The expression of the mrp gene encoding MRP and mRNAmrp was determined in tissues from 54 untreated patients with HCC, adjacent tissues from 24 patients with HCC and archival paraffin-embedded tissues from 12 patients with posthepatic cirrhosis. The relationship between the mrp gene expression and the change level of AFP was analyzed in the 24 postoperative HCC patients whose AFP level was measured after 2 weeks. All of the HCC patients were followed up. RESULTS: The percentage of positive expressions of MRP and mRNAmrp in the three kinds of tissues was 57.40%, 25.00%, 16.67%, and 72.22%, 37.50%, 33.33% respectively. Significant difference was noted in the untreated HCC tissue, compared to the other two tissues (P<0.05). No difference existed between the mrp gene expression and such clinicopathologic findings, as age, sex, and tumor size (P> 0.05), but the expression was related to the degree of differentiation of HCC (P<0.05). The effective rate of AFP in the mrp gene positive expression group or postoperative chemotherapeutic patients was lower than that in the negative group (P<0.05). Although no difference was seen in the 1-, 3-, 5-year survival rates of HCC patients (P>0.05), the mean survival time of postoperative HCC patients or the negative mrp gene expression group was longer than that of the positive group (P<0.05). CONCLUSIONS: Multidrug resistance (MDR) of HCC is related to mrp gene expression and initiates the intrinsic MDR. Detection of mrp gene expression is of great significance in accessing chemotherapeutic resistance of HCC, which provides evidence for reversing MDR in HCC. The mrp gene may be a useful marker in detecting prognosis of HCC patients because its expression is correlated with tumor differention and mean survival time of the patients.