Phase II study of CKD602, a camptothecin analog, in combination with carboplatin for the treatment of recurrent ovarian cancer

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Background: Belotecan (Camtobell, Chong Keun Dang Corp, Seoul, Korea; CKD602) is a camptothecin derivative with anti-tumor properties recently developed. This phase II study was designed to evaluate the toxicity and efficacy of belotecan combined with carboplatin in patients with recurrent epithelial ovarian cancer (EOC). Methods: Belotecan 0.3 mg/m2/day (days 1–5) and carboplatin AUC 5 (day 5) were administered every 3 weeks for 6 cycles. Eligible patients had recurrent EOC, peritoneal serous cancer, or fallopian tube cancer. The primary objective was to determine response rate defined by Response Evaluation Criteria in Solid Tumors and CA-125 response; other end points included toxicities and progression free survival (PFS). Results: Until this preliminary analysis, sixteen patients had received the treatment and 13 patients were evaluable for response. Eight patients had platinum-sensitive disease (minimum treatment free interval≥6 months) and 6 had platinum-resistant disease (minimum treatment free interval <6 months). Overall response rate was 53.9%; there were 3 complete responses (23.1%), 4 partial responses (30.8%), 4 patients with stable disease (30.8%), and two patients with progressive disease (15.4%). Grade 3 and 4 hematologic toxicities included neutropenia (38%), thrombocytopenia (25%), and anemia (15%); there was one episode of febrile neutropenia. None of the patients experienced grades 3 and 4 gastrointestinal toxicities, including nausea, vomiting, and anorexia. Conclusions: The newly developed topoisomerase I inhibitor, belotecan (CKD-602), combined with carboplatin is a well-tolerated regimen with activity in recurrent EOC; further testing of this regimen is warranted.

No significant financial relationships to disclose.

CEACAM5 and CEACAM6 are major target genes for Smad3-mediated TGF-β signaling

The carcinoembryonic antigen (CEAs) family consists of a large group of evolutionarily and structurally divergent glycoproteins. The transforming growth factor-beta (TGF-beta) signaling pathway has been implicated in the stimulation of CEA secretion in TGF-beta-sensitive colon cells, thereby possibly modulating cell adhesion and differentiation. However, the specific CEAs targeted by TGF-beta signaling or underlying mechanism of the expression of CEAs has not yet been clarified. In this study, we investigated the specific CEAs targeted by the TGF-beta signaling pathway. In nine human gastric cancer cell lines examined, TGF-beta-responsive cell lines showed positive expression of CEAs. Expression patterns of CEA proteins correlated well with the level of CEA (CEACAM5) and CEACAM6 transcripts in these cell lines, but CEACAM1 expression was not observed in all of these cells. To investigate the role of TGF-beta signaling in CEA expression, we selected two TGF-beta unresponsive gastric cancer cell lines; SNU638 cells that contain a mutation in the TGF-beta type II receptor and SNU484 cells that express low to undetectable level of the TGF-beta pathway intermediate protein, Smad3. Restoration of TGF-beta signaling in these cells induced expression of the CEAs and increased activity of both CEA (CEACAM5) and CEACAM6 promoters. CEA expression was observed in the epithelium of the stomach of wild-type mice, but was markedly decreased in Smad3 null mice. These findings suggest that CEA (CEACAM5) and CEACAM6 are major target genes for Smad3-mediated TGF-beta signaling.

Malignant schwannoma in an American buffalo (Bison bison bison)

A case of a malignant schwannoma in a 20-year-old male American buffalo (Bison bison bison) from the Grand Park Zoo, Gyeonggi Province, Republic of Korea is reported. The animal showed no apparent clinical signs before death except for wound on the neck. Grossly, neoplastic nodules of various sizes were observed on the skin, lung, heart, liver, stomach, mesentery and kidney. Histologically, the neoplastic nodules were composed of fusiform cells that formed multidirectional bundles. The tumour cells were arranged in interlacing bands and bundles. The nuclei were atypical, hyperchromatic, with blunt or round ends. In addition, few mitotic figures were observed in the skin, lung, heart, liver, stomach, intestine and kidney. Several immunohistochemical stains, e.g. vimentin, cytokeratin (CK), smooth muscle actin (SMA), S-100 and HMB45, were used in an attempt to differentially diagnose the tumour. The neoplastic cells tested positive to S-100, but negative to vimentin, CK, SMA and HMB45. Based on the above findings, this case was diagnosed as a malignant schwannoma. To the best of our knowledge, this is the first report of a schwannoma in an American buffalo (B. b. bison).

The effects of transplacental porcine circovirus type 2 infection on porcine epidemic diarrhoea virus-induced enteritis in preweaning piglets

The effects of transplacental porcine circovirus type 2 (PCV2) infection on porcine epidemic diarrhoea virus (PEDV)-induced enteritis were examined in neonatal piglets. Six pregnant sows were randomly allocated to an infected (n = 3) or control group (n = 3). Three pregnant sows were inoculated intranasally with 6 mL of tissue culture fluid containing 1.2 × 10⁵ tissue culture infective doses 50% (TCID₅₀)/mL of PCV2 strain SNUVR000470 three weeks before the expected farrowing date. Three control pregnant sows were similarly exposed to uninfected cell culture supernatants. Thirty piglets from PCV2-infected sows were randomly assigned to two groups (A and B) of 15 piglets each. Another 30 piglets from noninfected sows were randomly assigned to two groups (C and D) of 15 piglets each. The piglets in groups A and C were dosed orally at three days of age with 2 mL of virus stock (1 × 10^6.5 TCID₅₀/mL) of the PEDV strain, SNUVR971496, at the third passage.

The mean villous height and crypt depth (VH:CD) ratio in PEDV-infected piglets from PCV2-infected sows (group A) were significantly different from those of the PEDV-infected piglets from PCV2 negative sows (group C) at 36, 48, and 72 h post-inoculation (hpi) (P < 0.05). In PEDV-infected piglets from PCV2-infected sows (group A), significantly more PEDV nucleic acid was detected in the jejunal tissues (P < 0.05) at 24 hpi than in the same tissues of the PEDV-infected piglets from PCV2 negative sows (group C). Thereafter, at 36, 48, 60, and 70 hpi significantly more PEDV nucleic acid (P < 0.05) was detected in the jejunal tissues of the PEDV-infected piglets from PCV2 negative sows (group C) than those of the PEDV-infected piglets from the PCV2-infected sows (group A). It is concluded that the clinical course of PEDV disease was markedly affected by transplacental infection of PCV2.

Expression of cyclooxygenase-2 in breast carcinogenesis and its relation to HER-2/neu and p53 protein expression in invasive ductal carcinoma

The purpose of this study was to evaluate cyclooxygenase-2 (COX-2) expression in the successive steps of breast carcinogenesis and to determine its correlation with HER-2/neu and p53 expression in invasive ductal carcinomas of the breast. Immunohistochemical staining with anti-COX-2 antibody was performed in normal breast tissue, usual hyperplasia, ductal carcinoma in situ, and invasive ductal carcinoma. Expression of COX-2 in invasive ductal carcinoma was correlated with immunohistochemical expression of HER-2/neu and p53 protein. COX-2 expression was found to be progressively elevated along the continuum from normal breast tissue to invasive ductal carcinoma (P<0.001). COX-2 expression significantly correlated with p53 and HER-2/neu protein expression (P<0.05 and P<0.001). On multivariate analysis, only TNM stage and elevated COX-2 expression correlated with survival. Our results suggest that COX-2 may be involved in the carcinogenesis of the breast and may be an independent prognostic indicator in patients with invasive ductal carcinoma. HER-2/neu and p53 are likely to be involved in the regulation of COX-2 expression in invasive ductal carcinomas of the breast.

Expression of cyclooxygenase-2 in epithelial ovarian tumors and its relation to vascular endothelial growth factor and p53 expression

The purpose of this study was to evaluate cyclooxygenase-2 (COX-2) expression in epithelial ovarian tumors and its correlation with vascular endothelial growth factor (VEGF) and p53 expression. Immunohistochemical studies with anti-COX-2, anti-VEGF, and anti-p53 antibodies were carried out in 54 malignant and 23 borderline epithelial ovarian tumors. Elevated COX-2 expression was detected in 77.8% of ovarian carcinomas, which was significantly higher than that of borderline tumors (26.1%) (P < 0.001). In ovarian carcinomas, there was no significant correlation between COX-2 expression and other clinicopathologic features. Elevated VEGF expression was detected in 74.1% of ovarian carcinomas, and p53 expression was found in 64.8% of ovarian carcinomas. COX-2 expression was statistically correlated with elevated VEGF expression (P < 0.001) and p53 positivity (P < 0.05). On a univariate analysis, FIGO stage (P < 0.0001), histologic type (P= 0.0104), and COX-2 expression (P= 0.0135) were significant prognostic factors for overall survival. In a multivariate analysis, FIGO stage (P < 0.0001) was the only independent prognostic factor for poor survival. These findings suggest that COX-2 may play a role in the progression of epithelial ovarian tumors and that COX-2 expression may contribute to ovarian tumor angiogenesis by stimulating VEGF expression. p53 may be responsible for the regulation of COX-2 expression.

Expression of inflammatory cytokines in pigs experimentally infected with Mycoplasma hyopneumoniae

The expression of interleukin-1 (IL-1), tumour necrosis factor-alpha (TNF-alpha) and IL-6 were studied over a period of 35 days in the lungs of pigs experimentally infected with Mycoplasma hyopneumoniae, by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR), morphometric analysis and in-situ hybridization. Fifteen colostrum-deprived pigs aged 14 days were inoculated intranasally with M. hyopneumoniae. IL-1, TNF-alpha and IL-6 were detected by RT-PCR in the lungs of the infected pigs from 7 days post-inoculation (dpi) onwards, but not in the uninfected control pigs. Concurrent expression of all three cytokines was always observed, in association with lung lesions. Inflammatory cytokine-positive cells were detected in the lungs at 7 dpi, their number increasing at 21dpi, and decreasing thereafter. The results suggest that such cytokines play a role in mediating and regulating inflammation in M. hyopneumoniae infection.

Development of in-situ hybridization for the detection of Mycoplasma haemosuis (Eperythrozoon suis) in formalin-fixed, paraffin wax-embedded tissues from experimentally infected splenectomized pigs

Mycoplasma haemosuis DNA was detected in experimentally infected splenectomized pigs by in-situ hybridization (ISH) with a nonradioactive digoxigenin-labelled DNA probe. An 839 base pair DNA probe targeting a 16S rRNA gene was generated by the polymerase chain reaction. Eight 6-week-old pigs were inoculated intraperitoneally with 6 ml of M. haemosuis-infected pig blood and eight negative control pigs were inoculated intraperitoneally with 6 ml of M. haemosuis-free blood. Two pigs from each group were killed for examination at 3, 7, 15 and 30 days post-inoculation (dpi). Red blood cells infected with M. haemosuis were first detected by light microscopy at 3 to 7 dpi. No M. haemosuis was observed in negative control pigs. Hybridization signals were evident in blood from the infected pigs at 3 dpi. The ISH method developed in this study was useful for the detection of M. haemosuis DNA in formalin-fixed, paraffin wax-embedded tissues and may be valuable for studying the pathogenesis of M. haemosuis infection.

Synthetic Peptide-derived Antibody-based Immunohistochemistry for the Detection of Porcine Circovirus 2 in Pigs with Postweaning Multisystemic Wasting Syndrome

Porcine circovirus 2 (PCV2) was detected consistently in formalin-fixed paraffin wax-embedded lymph node and spleen from experimentally and naturally infected pigs by synthetic peptide-derived polyclonal antibody-based immunohistochemistry. Synthetic peptides were generated from open reading frame 2 of PCV2 by solid-phase peptide synthesis, purified by high performance liquid chromatography, and injected into rabbits to produce polyclonal antibody. Positive cells had large nuclei with abundant cytoplasm, and resembled macrophages. In serial sections, a similar distribution of PCV2 antigen and DNA was confirmed in virus-infected cells by immunohistochemistry and in-situ hybridization, respectively. The immunohistochemical method described was successfully applied to formalin-fixed, paraffin wax-embedded tissues and should prove helpful in diagnosing postweaning multisystemic wasting syndrome.

Birth abnormalities in pregnant sows infected intranasally with porcine circovirus 2

Six pregnant sows were inoculated intranasally at 3 weeks before the expected farrowing date with porcine circovirus 2 (PCV2). The PCV2-inoculated sows showed abortion and premature farrowing, whereas two uninfected negative control sows remained clinically healthy and farrowed normally. PCV2 antigen and DNA were detected by immunohistochemistry and in-situ hybridization, respectively, in lymph node, spleen, thymus, lung, tonsil and liver from both stillborn and liveborn piglets. Simultaneous detection of viral protein and DNA provided molecular evidence of PCV2 infection and replication. The experiment suggested that PCV2 is capable of crossing the placenta, replicating primarily in lymphoid tissues, and inducing reproductive failure.

Monitoring structural changes of liquids frozen in nanopores

Less dense packing of molecules in frozen liquids confined to cylindrical glass pores was observed to depend on pore size. This conclusion was derived by monitoring the rotational tunneling of methyl protons, which reside on studied molecules, with nuclear magnetic resonance. For example, the tunneling frequency of dimethyl sulfide and propionic acid at 10 K was observed to be larger in pores than in bulk. This is interpreted as being due to a decrease in the hindering potential. In another type of tunneling spectrum which is due to methyl-methyl interaction, observed in acetyl acetone at 10 K, the splitting decreases as the pores become smaller. It is demonstrated that in both types of materials the shifts of the methyl tunneling splittings in pores are the result of the reduced intermolecular interaction in the pore core region. This in turn indicates that the unit cell size of liquids frozen in nanopores is slightly increased. The increase is largest in smallest pores.