Splicing modulator FR901464 is a potential agent for colorectal cancer in combination therapy.

FR901464 (FR) was first described as an anticancer drug and later identified as a modulator of splicing factor 3B subunit 1 (SF3B1). Although the effectiveness of splicing modulators has been investigated in colorectal cancer (CRC) cells, their usefulness in animal experiments has not been confirmed. The association of SF3B1 with CRC progression and the influence of FR on transcriptional activity in CRC has not been fully elucidated. FR showed strong cytotoxicity against CRC cell lines, SF3B1-mutated cancer cell lines, and human fibroblasts with IC50 values less than 1 ng/ml. FR-resistant clones derived from HCT116, DLD1, Lovo, and CT26 cells showed IC50 values greater than 100 ng/ml. SF3B1 sequencing demonstrated low frequencies of SF3B1 mutations in CRC and mutations in codon 1074 of exon 22 in all FR-resistant clones. Unlike hematological malignancies, SF3B1 expression was not associated with CRC progression. Although FR showed significant growth inhibition in a xenograft model of RKO cells, severe toxicity was also induced. These data indicated CRC might be a suitable target of FR unless toxicity occurs. Microarray analysis and real-time quantitative PCR demonstrated downregulation of genes associated with Fanconi anemia (BRCA1 and BRCA2) and 28 driver oncogenes. These data suggested combination treatment of FR with other anticancer drugs whose sensitivity is associated with genes affected by FR treatment. Combination treatment with PARP1 inhibitor olaparib, whose sensitivity was enhanced by BRCA 1/2 deficiency, showed synergistic effects in CRC cells. Our data indicates the potential of FR in combination therapy rather than monotherapy for CRC treatment.

Whole cell vaccination using immunogenic cell death by an oncolytic adenovirus is effective against a colorectal cancer model.

Cancer vaccine application is limited to specific cancer types because few cancer-associated antigens are known to induce tumor rejection. Accordingly, we assessed the utility of Ad881, an oncolytic adenovirus in which viral replication was strictly regulated by the cancer-specific midkine promoter, as a cancer vaccine in a murine colorectal cancer model lacking specific cancer-associated antigens. In CT26 and CMT93 cells, Ad881 (multiplicity of infection: 100 or 1,000) showed stronger cytotoxicity and oncolysis in vitro than its equivalent replication-defective adenovirus, Ad884. CT26 cells (1 × 104) infected with Ad881 (multiplicity of infection: 1,000) for 24 hours were suitable as vaccine antigens without tumor formation in our model. Repeated vaccinations, but not single vaccination, induced a greater prophylactic immune response. The percentage of mice that rejected the tumor challenge was 0, 4, and 38% after no vaccination, single vaccination, and repeated vaccinations, respectively. Immunogenic cell death marker high-mobility group box 1 protein (HMGB1) and adenosine triphosphate in culture medium were higher after Ad881 infection (24.3 ng/ml and 48.2 nmol/l, respectively) than after Ad884 infection (8.6 ng/ml and 15.4 nmol/l, respectively) or oxaliplatin treatment (3.7 ng/ml and 1.8 nmol/l, respectively). These results indicate that repeated whole cell vaccination using an oncolytic adenovirus may be a potent approach to evoke immunogenic cell death.

Prognostic significance of classified extramural tumor deposits and extracapsular lymph node invasion in T3-4 colorectal cancer: a retrospective single-center study.

BACKGROUND: Extramural tumor deposits (TDs) and extracapsular lymph node involvement (ECLNI) are considered to be poor prognostic factors in patients with T3-4, N0-2, M0 colorectal cancer (CRC). Although TDs are known to have multiple origins and pleomorphic features, the prognostic significances of the different type of TDs have not yet been established. METHODS: We performed a retrospective review of 385 consecutive patients with T3-4, N0-2, M0 CRC who received curative resection at our institution between 2006 and 2012. We classified the TDs into two groups: invasive-type TD (iTD), which is characterized by the presence of lymphatic invasion, vascular invasion, perineural invasion, or undefined cancer cell clusters and nodular-type TD (nTD), which is characterized by a smooth or irregular-shaped tumor nodule other than an iTD. ECLNI was defined as invasion of cancer cells into capsular collagen tissues or adipose tissues beyond the capsular collagen. Multivariate analyses were used to assess the prognostic significance of iTD, ND, and ECLNI for relapse-free survival (RFS), disease-specific survival (DSS), and sites of recurrence. RESULTS: In patients without lymph node (LN) metastasis, the incidences of iTD and nTD were both in the range of 2-3 %. Conversely, in patients with LN metastasis, the incidences of iTD, nTD, and ECLNI were 31, 22, and 34 %, respectively. iTD, nTD, and ECLNI were all significant independent adverse factors for RFS in rectal cancer, and were all associated with pT, pN, and LN ratio. iTD was a significant independent adverse prognostic factor for DSS in rectal cancer, metastasis to the liver in colorectal cancer, and distant LN metastasis in colon cancer. ECLNI was a significant independent prognostic factor for RFS in colon cancer. CONCLUSIONS: Classifying TDs and assessing ECLNI may help establish significant prognostic factors for patients with T3-4, N0-2, M0 CRC.

Different mechanisms causing loss of mismatched human leukocyte antigens in relapsing t(6;11)(q27;q23) acute myeloid leukemia after haploidentical transplantation.

Mismatched human leukocyte antigens (HLAs) on leukemic cells can be targeted by donor T cells in HLA-mismatched/haploidentical stem cell transplantation. In two cases of acute myeloid leukemia with t(6;11)(q27;q23) abnormality presented here, flow cytometry analysis showed a lack of HLA-A unshared between recipients and donors in relapsing leukemic cells after HLA-haploidentical transplantation. However, high-resolution HLA genotyping showed that one case lacked a corresponding HLA haplotype, whereas the other preserved it. These cases suggest that leukemic cells, which lacked mismatched HLA expression, might have an advantage in selective expansion under donor T-cell immune surveillance after HLA-haploidentical transplantation. Most importantly, down-regulation of unshared HLA expression potentially occurs by genetic alterations other than loss of HLA alleles.