Co-delivery of LETM1 and CTMP synergistically inhibits tumor growth in H-ras12V liver cancer model mice

As hepatocellular carcinoma (HCC) is one of the most common tumors worldwide, development of novel therapeutic approaches for HCC is urgently needed. Two different genes, LETM1 and CTMP, which target mitochondrial functions, were chosen and linked using 2A-peptide sequence. Successful self-cleavage of 2A-peptide induced synergistic antitumor effect in the liver of H-ras12V, the HCC model mice, by simultaneous activation of LETM1 (Leucine zipper/EF hand-containing transmembrane-1) and CTMP (carboxyl-terminal modulator protein). Overexpression of LETM1 and CTMP significantly reduced the incidence of tumorigenesis, which were confirmed by gross and microscopic observations. Morphological changes in mitochondria, such as swelling and loss of cristae, were significant, and the prolonged activation of defects in mitochondrial function led to mitochondria-mediated apoptosis. Furthermore, with CTMP as a direct binding partner of Akt1, and LETM1 as a binding partner of CTMP, LETM1-2A-CTMP downregulated the Akt1 pathway at both Ser473 and Thr308 sites of phosphorylation. Proliferation and angiogenesis, which are important in cancer prognosis, were reduced in tumor sites after introduction of LETM1-2A-CTMP. Taken together, the results indicate that introduction of the mitochondria-targeting genes, LETM1 and CTMP, and self-processing capacity of 2A-peptide sequence exerts an antitumor effect in liver of H-ras12V mice, suggesting its potential as a tool for gene therapy.

Osteogenic potential of mandibular vs. long-bone marrow stromal cells

Although fundamentally similar to other bones, the jaws demonstrate discrete responses to developmental, mechanical, and homeostatic regulatory signals. Here, we hypothesized that rat mandible vs. long-bone marrow-derived cells possess different osteogenic potential. We established a protocol for rat mandible and long-bone marrow stromal cell (BMSC) isolation and culture. Mandible BMSC cultures formed more colonies, suggesting an increased CFU-F population. Both mandible and long-bone BMSCs differentiated into osteoblasts. However, mandible BMSCs demonstrated augmented alkaline phosphatase activity, mineralization, and osteoblast gene expression. Importantly, upon implantation into nude mice, mandible BMSCs formed 70% larger bone nodules containing three-fold more mineralized bone compared with long-bone BMSCs. Analysis of these data demonstrates an increased osteogenic potential and augmented capacity of mandible BMSCs to induce bone formation in vitro and in vivo. Our findings support differences in the mechanisms underlying mandible homeostasis and the pathophysiology of diseases unique to the jaws.

-93G>A polymorphism of hMLH1 associated with prognosis for patients with colorectal cancer

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Background: Polymorphisms in the DNA repair genes may contribute to variation in DNA repair capacity, thereby affecting the risk of carcinogenesis and prognosis of colorectal cancer. Accordingly, the present study analyzed polymorphisms of DNA repair genes and their impact on the prognosis for patients with colorectal cancer. Methods: Three hundred and ninety- seven consecutive patients with curatively resected colorectal adenocarcinoma were enrolled in the present study. The genomic DNA was extracted from fresh colorectal tissue and 14 polymorphisms of DNA repair genes (XRCC1, hMLH1, ERCC2, ERCC4, VARS2[rs2074511, rs2249459], XPA, XPC, POLR2A, POLR2B, RFC1, RFC4, XAB2, DNMT3B) determined using a PCR-RFLP assay. Results: The median age of the patients was 63 years (range, 21–85), and 218 (54.9%) patients had colon cancer and 179 (45.1%) patients rectal cancer. Pathologic stages after surgery were as follows: stage 0/I (n=86, 21.7%), stage II (n=146, 36.8%), stage III (n=145, 36.5%), and stage IV (n=20, 5.0%). Multivariate survival analysis including stage, differentiation, age, and CEA level showed that the survival for the patients with the -93AA genotype of hMLH1 was worse than for the patients with the combined -93GG and GA genotype (overall survival: hazard ratio [HR]=2.953, 95% Confidential Interval [CI], 1.273–6.850, P=0.012; disease-free survival: HR=2.299, 95% CI, 1.417–3.730, P=0.001), whereas the other polymorphisms were not associated with survival. Conclusions: The -93G>A polymorphism of hMLH1 was found to be an independent prognostic marker for patients with colorectal cancer. Accordingly, in addition to the pathologic stage, the analysis of -93G>A polymorphism of hMLH1 can help identify patient subgroups at high risk of a poor disease outcome.

No significant financial relationships to disclose.

Phase I dose-finding study of sorafenib in combination with capecitabine and cisplatin as a first-line treatment in patients with advanced gastric cancer

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Background: We conducted a phase I dose-finding study of sorafenib (S) in combination with capecitabine (X) and cisplatin (P) in patients with previously untreated metastatic or inoperable advanced gastric cancer. Methods: Four dose levels of S, X, and P combination were tested. The doses of S (p.o. daily), X (p.o. on days 1–14), and P (i.v. on day 1) were escalated at the following schedule; level 1: S 400 mg/d, X 1,600 mg/m2/d, P 80 mg/m2; level 2: S 800 mg/d, X 1,600 mg/m2/d, P 80 mg/m2; level 3: S 800 mg/d, X 2,000 mg/m2/d, P 80 mg/m2; level 1A: S 800 mg/d, X 1,600 mg/m2/d, P 60 mg/m2. The cycle was repeated every 3 weeks. Dose limiting toxicities (DLTs) were evaluated only in the first cycles and a standard 3+3 dose escalation design was implemented. Results: A total 21 pts were enrolled in the study. No DLTs were observed at dose level 1 (n=3). One DLT (grade 3 diarrhea) was noted at dose level 2 (n=6), and 2 DLTs (two grade 4 neutropenias longer than 5 days in duration) were observed at dose level 3 (n=6), which made the level 3 dose the maximum tolerated dose (MTD). However, at cycle 2 and thereafter at dose level 2, the relative dose intensity (RDI) of S and X could not be maintained (mostly below 80%) due to the frequent dose reductions and cycle delays. So, we explored a new dose level (1A) between dose level 1 and 2. Since no DLTs were found in 6 patients at level 1A with RDI mostly above 80% throughout the treatment period, level 1A was determined as recommended dose (RD). Most frequent grade 3 and 4 hematologic toxicities were neutropenia (25.0% of cycles), and most frequent grade 2 and 3 non-hematologic toxicities were hand-foot syndrome (9.4%), asthenia (7.0%), and anorexia (5.5%). The objective responses were confirmed in 10 out of 16 patients with measurable lesions (62.5%; 95% CI, 38.8–86.2%). With a median follow-up of 8.1 months, estimated median progression-free survival was 10.0 months (95% CI, 1.6–18.4 months) and median overall survival has not been reached. Conclusions: Diarrhea and neutropenia were DLTs in this S, X, and P combination. The dose schedule of sorafenib 400 mg po bid daily with capecitabine 800 mg/m2 po bid on days 1–14, and cisplatin 60 mg/m2 iv on day 1 in every 3 weeks is recommended for further development in AGC.

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A phase II study of imatinib mesylate as adjuvant treatment for curatively resected high-risk localized gastrointestinal stromal tumors

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Background: In our previous study, the presence of c-kit mutation as well as tumor size and mitotic count was an independent poor risk factor for relapse after curative resection of primary localized GIST. The patients with all the 3 poor risk factors had only 30% of 2 year relapse free survival rate (RFSR). (Kim, et al. Clin Cancer Res, 2004) It is also well known that c-kit exon 11 mutant GISTs respond better to imatinib treatment than the other mutant or wild type GISTs. Therefore, the patients who have primary localized GISTs with large size, high mitotic count, and c-kit exon 11 mutation may be the best candidate of adjuvant imatinib treatment. In this phase II study, we have evaluated the efficacy and safety of adjuvant imatinib for this patient group. Methods: Patients who underwent complete resection of a primary GIST with 1) c-kit exon 11 mutation, and 2) ≥10 mitoses/50 HPF, or tumor size ≥10 cm, or ≥5 mitoses/50 HPF and tumor size ≥5 cm were eligible. Patients received imatinib 400mg p.o. daily until recurrence of disease, intolerable toxicities, or for 2 years. The primary end point was relapse-free survival (RFS). Results: A total of 47 patients from 4 centers in Korea were enrolled. The median age was 57.0 years. Stomach was the most common primary site (n=31). Median primary tumor size was 7.5cm and median mitoses index was 12/50 HPF. With a median follow-up of 26.9 months, the median RFS and overall survival (OS) have not yet been reached. RFSR was 97.7% at 1-year and 92.7% at 2-years. Six relapses (12.8%) were documented among the 47 patients. The treatments were generally well tolerated. Grade 3–4 toxicities included neutropenia 27.7%, rash 8.5%, constipation 4.3%, anorexia 2.1%, vomiting 2.1%, and pruritis 2.1%. There were no episode of febrile neutropenia and treatment-related death. Conclusions: Postoperative adjuvant imatinib for 2 years were safe and could prolong the RFS in patients with high-risk of recurrence following complete surgical resection of the primary GIST. However, it remains unknown if this benefit in RFS can be translated into OS benefit. So, further follow-up is needed with comparison of OS with historical controls who could be use imatinib after recurrence.

[Table: see text]

Prognostic impact of the NFKB1 insertion/deletion promoter polymorphism on survival in patients with surgically resected gastric cancer

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Background: The present study analyzed the functional insertion/deletion polymorphism in the promoter region of NKFB1 gene and their impact on the prognosis for patients with gastric adenocarcinoma. Methods: Five hundred and three consecutive patients with surgically resected gastric adenocarcinoma were enrolled in the present study. The genomic DNA was extracted from paraffin-embedded tissue and the -94 insertion/deletion ATTG polymorphism of NFKB1 determined using a PCR- RFLP assay. Results: The NFKB1 promoter gene polymorphism was successfully amplified in 97.8% of the cases. There were no sexual differences in relation to the genotype and allele. No correlation was observed between the frequency of the genotype or allele and the T, N, or M stage. The multivariate survival analysis showed no association between the NFKB1 -94 insertion/deletion promoter polymorphism and the disease-free survival or overall survival of the patients with gastric cancer. Conclusions: The functional NFKB1 promoter polymorphism was not found to be a prognostic marker for Korean patients with surgically resected gastric adenocarcinoma.

No significant financial relationships to disclose.

Expression of programmed cell death 5 gene involves in regulation of apoptosis in gastric tumor cells

The protein of programmed cell death 5 (PDCD5) is believed to participate in regulation of apoptosis. Although PDCD5 is reducibly expressed in various human tumors, it is not clear which expression level of PDCD5 is in gastric cancer (GC). In this study, we have systematically employed the approaches of RT-PCR, Real- time PCR, Immunohistochemistry (IHC), Immunofluorescence staining (IFS) and Western blot to determine the PDCD5 expression in GC cells and primary tumors, at mRNA and protein level, respectively. Our data revealed that the positive rate of PDCD5 expression in the gastric tumor tissues was significantly less than that of the normal tissues (14 out of 102 vs 36 out of 51), whereas, the decreased expression of PDCD5 protein was well correlated with the up-regulated expression of Bcl-2 in these tissues, and the up-regulated expression and nuclear translocation of PDCD5 protein were verified in the apoptotic GC cells induced by Diallyl trisulfide (DATS). Furthermore, the survival curve has suggested that the more PDCD5 expressions were found in the patients, the longer the survival periods were. Therefore, our observations lay down a reasonable postulation that PDCD5 may play a key role to regulate the apoptotic processes in the GC cells and gastric tumors.