[Clinical factors of pathological complete response after neoadjuvant chemoradiotherapy in rectal cancer]

Objective: To explore the feasibility of clinical factors to predict the pathological complete response after neoadjuvant chemoradiotherapy in rectal cancer. Methods: A retrospective analysis was performed on clinical factors of 162 patients with rectal cancer, who underwent neoadjuvant chemoradiotherapy in the General Hospital of People's Liberation Army from January 2011 to December 2018.According to the postoperative pathological results, the patients were divided into pathological complete response (pCR) group and non-pathological complete response group (non-pCR group) to check the predictive clinical factors for pCR. Results: Twenty-eight cases achieved pCR after neoadjuvant chemoradiation (17.3%, 28/162). Univariate analysis showed that patients with higher differentiation (P=0.024), tumor occupation of the bowel lumen≤1/2 (P=0.006), earlier clinical T stage (P=0.013), earlier clinical N stage (P=0.009), the time interval between neoadjuvant chemoradiotherapy and surgery>49 days (P=0.006), and maximum tumor diameter≤5 cm (P=0.019) were more likely to obtain pCR, and the differences werestatistically significant. Multivariate analysis showed that tumor occupation of the bowel lumen≤1/2 (P=0.01), maximum tumor diameter≤5 cm (P=0.035), and the interval>49 days (P=0.009) were independent factors in predicting pCR after neoadjuvant therapy. Conclusion: Tumor occupation of the bowel lumen, maximum tumor diameter, and the time interval between neoadjuvant chemoradiotherapy and surgery can predict the pCR in rectal cancer.

[HBV genotyping based on key epitopes of PreS1 antigen and its correlation with genotyping by full-length PreS1 sequencing]

Objective: The aim was to investigate the genotype distribution of two major epitopes of large surface protein (PreS1) of hepatitis B in Chinese patients and to explore the association between the genotypes of these two epitopes, and to determine whether PreS1 full-length genotype could be revealed according to the polypeptide sequence of key epitopes. Methods: HBV DNA was extracted from the serum of patients for PCR amplification. 278 samples amplified successfully were sequenced and compared with the known HBV sequences in Genbank to determine the two key epitopes of HBV PreS1 genotype (amino acid epitope 21-47 and 94-117, abbreviated as P21 and P94) and PreS1 full-length genotypes. The correlation among three genotyping approaches was analyzed by Cohen's kappa coefficient to verify the consistency between the key-epitope genotyping and the full-length preS1 genotyping. Results: 232 samples were successfully sequenced. The genotyping based on the kind of P21 epitope protein sequence, 201 cases for genotype C, 23 cases for genotype B and 8 cases for uncertain genotypes and genotyping based on the form of P94 epitope protein sequence, 199 cases for genotype C, 25 cases for genotype B and 8 cases for indeterminate genotypes. Lastly, the genotyping based on sequence of the full-length PreS1 sequence, 207 and 25 cases for genotype C and B. P21 or P94 epitope genotyping and PreS1 full length genotyping were highly consistent, respectively, 96.55% and 96.12%, and the two epitopes (P21and P94) genotyping have parallel consistency (93.10%). Conclusion: In this study, an innovatively genotyping method based on the amino acid sequence of key epitopes was proposed. The genotypes of HBV in china were mainly B and C genotypes, and the genotypes of key conserved epitopes of HBV PreS1 were highly consistent with the full-length genotyping ( > 96%). Moreover, genotyping with one or two key epitopes can be used in place of the full-length genotyping.

Overexpression of POSTN in Tumor Stroma Is a Poor Prognostic Indicator of Colorectal Cancer

BACKGROUND

Tumor microenvironment has recently drawn attention in that it is related with tumor prognosis. Cancer-associated fibroblast also plays a critical role in cancer invasiveness and progression in colorectal cancers. Periostin (POSTN), originally identified to be expressed in osteoblasts and osteoblast-derived cells, is expressed in cancer-associated fibroblasts in several tissue types of cancer. Recent studies suggest an association between stromal overexpression of POSTN and poor prognosis of cancer patients.

METHODS

We analyzed colorectal cancer cases for their expression status of POSTN in tumor stroma using immunohistochemistry and correlated the expression status with clinicopathological and molecular features.

RESULTS

High level of POSTN expression in tumor stroma was closely associated with tumor location in proximal colon, infiltrative growth pattern, undifferentiated histology, tumor budding, luminal necrosis, and higher TNM stage. High expression status of POSTN in tumor stroma was found to be an independent prognostic parameter implicating poor 5-year cancer-specific survival and 5-year progression-free survival.

CONCLUSIONS

Our findings suggest that POSTN overexpression in tumor stroma of colorectal cancers could be a possible candidate marker for predicting poor prognosis in patients with colorectal cancers.

Prognostic Implication of M2 Macrophages Are Determined by the Proportional Balance of Tumor Associated Macrophages and Tumor Infiltrating Lymphocytes in Microsatellite-Unstable Gastric Carcinoma

Tumor associated macrophages are major inflammatory cells that play an important role in the tumor microenvironment. In this study, we investigated the prognostic significance of tumor associated macrophages (TAMs) in MSI-high gastric cancers using immunohistochemistry. CD68 and CD163 were used as markers for total infiltrating macrophages and M2-polarized macrophages, respectively. The density of CD68+ or CD163+ TAMs in four different areas (epithelial and stromal compartments of both the tumor center and invasive front) were analyzed in 143 cases of MSI-high advanced gastric cancers using a computerized image analysis system. Gastric cancers were scored as "0" or "1" in each area when the density of CD68+ and CD163+ TAMs was below or above the median value. Low density of CD68+ or CD163+ macrophages in four combined areas was closely associated with more frequent low-grade histology and the intestinal type tumor of the Lauren classification. In survival analysis, the low density of CD163+ TAMs was significantly associated with poor disease-free survival. In multivariate survival analysis, CD163+ TAMs in four combined areas, stromal and epithelial compartments of both tumor center and invasive front were independent prognostic indicator in MSI-high gastric cancers. In addition, the density of CD163+ TAMs correlated with tumor infiltrating lymphocytes (TILs). Our results indicate that the high density of CD163+ TAMs is an independent prognostic marker heralding prolonged disease-free survival and that the prognostic implication of CD163+ TAMs might be determined by the proportional balance of TAMs and TILs in MSI-high gastric cancers.

Improved Therapeutic Outcome Following Combination Immunogene Vaccination Therapy in Murine Myeloma

Increasing evidence suggests a role for immunologic vaccination and therapy in the management of minimal residual myeloma. We have previously demonstrated a synergistic effect of combining the Th1 stimulating cytokine IL-12 with the co-stimulatory molecule CD80 in murine myeloma vaccination therapy. We reasoned that the efficacy of such treatment might be further improved by incorporating additional gene products which enhance the function of antigen presenting cells. Studies were therefore conducted with murine myeloma BM1 cells expressing Flt3L (membrane bound or soluble forms) or GM-CSF and the IL-12 x CD80 combination. Single agent and combined therapeutic approaches were explored. All gene-modified BM1 cells, except BM1/IL-12 x CD80, developed tumors when subcutaneously injected into BALB/c mice. As prophylactic tumor vaccines, the combined use of gene-modified BM1/sFlt3L+GM-CSF+IL-12 x CD80 was most effective, providing 100% protection against subsequent parental BM1 tumor challenge. By comparison, only partial protection was observed with any single gene-engineered tumor vaccine. Notably, IL-12 x CD80 coexpressing BM1 cell vaccines were the most effective therapeutic vaccine in a minimal disease model. Such protective vaccination was achieved by stimulation of lymphocyte proliferation and enhancement of cytotoxic lymphocyte activity.

Tricistronic viral vectors co-expressing interleukin-12 (1L-12) and CD80 (B7-1) for the immunotherapy of cancer: preclinical studies in myeloma

Synergy between interleukin-12 (IL-12) and B7-1 (CD80) for cancer immunotherapy has previously been demonstrated in animal models of breast cancer, lymphoma, and multiple myeloma. With a view to human clinical application, tricistronic retroviral and adenovirus vectors co-expressing IL-12 (IL-12p40 plus IL-12p35) and CD80 were constructed by utilizing two internal ribosome entry site (IRES) sequences to link the three cDNAs. A murine stem cell virus (MSCV)-based retroviral vector (MSCV-hIL12.B7) utilized distinct IRES sequences from the encephalomyocarditis virus (EMCV) and the foot-and-mouth disease virus (FMCV), whereas Ad5-based adenovirus vectors contained transcriptional units with two EMCV IRES sequences under the control of murine (AdMh12.B7) or human (AdHh12.B7) cytomegalovirus promoters. AdMh12.B7 was found to consistently direct higher levels of IL-12 and CD80 expression than AdHh12.B7 following infection of a number of human tumor cell lines. In preclinical studies, the human myeloma cell line U266 was infected with MSCV-hIL12.B7 and a resulting clonal cell line, U/MSCV-h12.B7, was generated with stable expression of CD80 and secreting IL-12 at 1 ng/24 h/10(6) cells. By comparison, following AdMh12.B7 infection, 81% of infected U266 cells (U/AdMh12.B7) expressed CD80 and secreted IL-12 at 25-50 ng/24 h/10(6) cells. Both engineered myeloma cell lines stimulated enhanced allogeneic mixed lymphocyte proliferation and provoked increases in cytotoxic T-lymphocyte responses and gamma-interferon release from normal donor lymphocytes exposed to parental U266 cells. These results suggest potential clinical utility of AdMh12.B7 in immunotherapy strategies for the treatment of multiple myeloma and other cancers.

Adenovirus-mediated human endostatin gene delivery demonstrates strain-specific antitumor activity and acute dose-dependent toxicity in mice

Purified recombinant mouse endostatin protein has been reported to regress established murine solid tumors by inhibiting the proliferation of endothelial cells. To develop a clinical gene therapy strategy with endostatin, we cloned the cDNA of human endostatin by RT-PCR from human placenta. A 150-bp sequence encoding the IgG leader peptide was fused in frame to the 5' end of the endostatin cDNA and recombinant adenoviruses, AdENDO-YFP and AdENDO, carrying endostatin gene expression cassettes were rescued. AdENDO-YFP infects cultured mammalian cells at high efficiency and expresses a biologically active human endostatin in secreted form at high levels both in vitro and in vivo. When delivered in vivo, a strain-specific expression pattern was observed, with the highest and longest endostatin expression in 129/J mice. After systemic delivery of 2 x 10(9) PFU of AdENDO-YFP into 129/J mice, human endostatin expression was achieved at a mean value of 1.34 +/- 0.42 microg/ml of serum (n = 6) and inhibition of lung metastasis was observed in an EOMA tumor model. However, high dose intravenous delivery of AdENDO-YFP and AdENDO was associated with severe acute toxicity in recipient mice that included loss of weight, bleeding, and death of animals. These events were not observed with the injection of identical doses of a control adenovirus that did not contain the endostatin gene. Because the endostatin adenovirus-associated acute toxicity was also observed in immunodeficient NCRNU-M nude mice, the toxicity does not appear to be the result of the immunogenicity against human endostatin or the EYFP protein.

Murine phosphatidylserine-specific phospholipase A1 (Ps-pla1) maps to chromosome 16 but is distinct from the lpd (lipid defect) locus

We have previously generated a mouse transgenic line with an insertional mutation designated lpd that demonstrates a phenotype of hypertriglyceridemia and fatty liver. Since the recently identified phosphatidylserine-specific phospholipase A1 (PS-PLA1) demonstrates significant homology to triglyceride lipases, we reasoned that the mouse Ps-plaI gene may be the disrupted gene within the lpd locus. Using a rat PS-PLA1 cDNA sequence to search the EST database, we identified a mouse EST homolog AA839424. Sequencing analysis of AA839424 revealed a putative Ps-pla1 protein of 456 amino acids with extensive overall structural conservation with human and rat PS-PLA1 and with triglyceride lipases. Conserved sequences in Ps-pla1 include a lipase consensus sequences GxSxG, a catalytic triad, and eight of the ten conserved cysteine residues that are required for tertiary structure. Mouse Ps-plal carries a phosphatidylserine-binding motif that is absent in all triglyceride lipases. Using a mouse whole-genome radiation hybrid (WG-RH) mapping panel (T31), we mapped mouse Ps-pla1 to Chromosome (Chr) 16 between genetic markers D16Mit194 and D16Mit38, which is 17.1 cM centromeric to the lpd locus. On the basis of chromosome location, we conclude that Ps-pla1 and lpd are distinct genes in lipid metabolism.

Identification of c-myc promoter-binding protein and X-box binding protein 1 as interleukin-6 target genes in human multiple myeloma cells

Interleukin-6 (IL-6) is implicated in the in vivo proliferation of malignant plasma cells in multiple myeloma. To define the molecular basis of the IL-6-induced mitogenic response in myeloma cells, we applied STAR (subtractive transcriptional amplification of mRNA), a new differential expression analysis technology, to isolate mRNAs preferentially expressed in IL-6-treated versus untreated cultures of the factor-responsive myeloma cell line U266. From the resulting collection of STAR clones, sequence information was obtained for a total of 72 distinct transcripts. Of these, 29 were found to correspond to known genes, 22 matched expressed sequence tags in public databases and 21 showed no sequence similarity to any existing entries. Among the known genes uncovered in the screen were those encoding proteins that function in cell division, cell signalling and gene/protein expression. Northern blot analysis documented that two transcription factor genes chosen for further study, c-myc promoter-binding protein (MBP-1) and X-box binding protein 1 (XBP-1), were up-regulated in U266 cells about 3-fold relative to the cell cycle-dependent beta-actin gene 12 h after IL-6 treatment. Both genes were also similarly up-regulated by IL-6 in factor-dependent ANBL-6 myeloma cells. These results indicate that MBP-1 and XBP-1 are IL-6 genes in myeloma cells; as such, they may play a role in IL-6-mediated growth control in multiple myeloma.

Characterization of lpd (lipid defect): a novel mutation on mouse chromosome 16 associated with a defect in triglyceride metabolism

Recent epidemiological studies have identified plasma triglyceride as a risk factor for atherogenesis. We have generated a mouse transgenic line that carries a recessive mutation designated lpd (lipid defect). Homozygous lpd mice develop as runts and die by age 10-15 days with striking liver pathology characterized by the presence of numerous lipid-containing vacuoles and extensive accumulation of triglycerides. Cloning of the mutant insertion locus and the wild-type lpd locus have revealed a duplication of host genomic sequences at the site of integration. Mapping of the lpd locus with the Jackson Laboratory BSS interspecific backcross panel of (C57BL/6JEi x SPRET/Ei) F1 x SPRET/Ei placed the lpd locus to the distal part of chromosome 16. These observations suggest that the transgene disrupts a putative gene at the lpd locus and that lpd is a novel locus related to triglyceride metabolism. The lpd mutant mice may serve as models for human disorders of fatty livers or hypertriglyceridemia.

Genetic mapping of two mouse homeobox genes Tlx-1 and Tlx-2 to murine chromosomes 19 and 6

We have previously cloned two mouse homeobox genes Tlx-1 (T-cell leukemia homeobox gene-1) and a related gene Tlx-2 based on their homology to human HOX11, a putative proto-oncogene involved in human T-cell leukemia. We have mapped Tlx-1 to mouse chromosome 19 and Tlx-2 to chromosome 6 by linkage analysis using an interspecific backcross (C57BL/6J x Mus spretus) F1 x M. spretus. The proposed gene orders and genetic distances for Tlx-1 and Tlx-2 are centromere 19-Lpc-1-(25.53 cM)-Pltr-4-(5.32 cM)-Tlx-1- (3.19 cM)-Ins-1-(7.45 cM)-Xmv-18, and centromere 6-Tcrb-(12.90 cM)-Mltr-3-(10.75 cM)-Tlx-2-(18.42 cM)-Xmv-6.

[Using BPV transforming foci as selective markers to express HBsAg]

We constructed a plasmid pBMTHBR2 containing mouse MT promoter, entire HBsAg gene (preS and S gene), splicing signal from SV40 and complete BPV genome. Using calcium phosphate precipitation technique to transform C127 Cells and using BPV transforming foci as selective markers, we obtained transformed cell clones. The experiment shows that 57% of the cloned cell lines can secrete HBsAg continuously.