hnRNPK promotes gastric tumorigenesis through regulating CD44E alternative splicing.

BACKGROUND: The high prevalence of alternative splicing among genes implies the importance of genomic complexity in regulating normal physiological processes and diseases such as gastric cancer (GC). The standard form of stem cell marker CD44 (CD44S) and its alternatives with additional exons are reported to play important roles in multiple types of tumors, but the regulation mechanism of CD44 alternative splicing is not fully understood. METHODS: Here the expression of hnRNPK was analyzed among the Cancer Genome Atlas (TCGA) cohort of GC. The function of hnRNPK in GC cells was analyzed and its downstream targeted gene was identified by chromatin immunoprecipitation and dual luciferase report assay. Finally, effect of hnRNPK and its downstream splicing regulator on CD44 alternative splicing was investigated. RESULTS: The expression of hnRNPK was significantly increased in GC and its upregulation was associated with tumor stage and metastasis. Loss-of-function studies found that hnRNPK could promote GC cell proliferation, migration, and invasion. The upregulation of hnRNPK activates the expression of the splicing regulator SRSF1 by binding to the first motif upstream the start codon (- 65 to - 77 site), thereby increasing splicing activity and expression of an oncogenic CD44 isoform, CD44E (has additional variant exons 8 to 10, CD44v8-v10). CONCLUSION: These findings revealed the importance of the hnRNPK-SRSF1-CD44E axis in promoting gastric tumorigenesis.

Predictive value of serum alpha-fetoprotein for tumor regression after preoperative chemotherapy for rectal cancer.

BACKGROUND: Preoperative therapy is widely used in locally advanced rectal cancer. It can improve local control of rectal cancer. However, there are few indicators that can predict the effect of preoperative chemotherapy accurately. AIM: To investigate whether the increase in serum α-fetoprotein (AFP) can predict better efficacy of preoperative chemotherapy. METHODS: This was a retrospective study. We analyzed 125 patients admitted between 2017 and 2019 with locally advanced rectal cancer. All patients received six cycles of preoperative chemotherapy (mFOLFOX6 every 2 wk). Serum AFP of 26 patients rose slightly after three or four cycles of chemotherapy, and fell to normal again within 2 mo. The other 99 patients had a normal level of serum AFP during chemotherapy. Patients were divided into two groups (AFP risen and AFP normal). According to postoperative pathology, we compared tumor regression and complete response rate between the two groups. The primary outcome measure was the tumor regression grade (TRG) after chemotherapy. The difference in pathological complete response between the two groups was also investigated. RESULTS: There were no tumor progression and distant metastasis in both groups during preoperative chemotherapy. Patients in the AFP risen group achieved better TRG 0/1 than those in the AFP normal group (61.5% vs 39.4%). The increase in AFP was a significant predictor for better tumor regression [χ 2 = 4.144, odds ratio (OR) = 2.666, P = 0.04]. In the AFP risen group, the complete response rate was 30.8%, which was higher than in the AFP normal group (30.8% vs 12.1%, χ 2 = 4.542, OR = 3.251, P = 0.03). CONCLUSION: Patients with a slight increase in serum AFP can achieve better tumor regression during preoperative chemotherapy, and are more likely to achieve pathological complete response.

Prognostic impact of tumor deposits on overall survival in colorectal cancer: Based on Surveillance, Epidemiology, and End Results database.

BACKGROUND: In colorectal cancer, tumor deposits (TDs) are considered to be a prognostic factor in the current staging system, and are only considered in the absence of lymph node metastases (LNMs). However, this definition and the subsequent prognostic value based on it is controversial, with various hypotheses. TDs may play an independent role when it comes to survival and addition of TDs to LNM count may predict the prognosis of patients more accurately. AIM: To assess the prognostic impact of TDs and evaluate the effect of their addition to the LNM count. METHODS: The patients are derived from the Surveillance, Epidemiology, and End Results database. A prognostic analysis regarding impact of TDs on overall survival (OS) was performed using Cox regression model, and other covariates associating with OS were adjusted. The effect of addition of TDs to LNM count on N restaging was also evaluated. The subgroup analysis was performed to explore the different profile of risk factors between patients with and without TDs. RESULTS: Overall, 103755 patients were enrolled with 14131 (13.6%) TD-positive and 89624 (86.4%) TD-negative tumors. TD-positive patients had worse prognosis compared with TD-negative patients, with 3-year OS rates of 47.3% (95%CI, 46.5%-48.1%) and 77.5% (95%CI, 77.2%-77.8%, P < 0.0001), respectively. On multivariable analysis, TDs were associated poorer OS (hazard ratio, 1.35; 95%CI, 1.31-1.38; P < 0.0001). Among TD-positive patients, the number of TDs had a linear negative effect on disease-free survival and OS. After reclassifying patients by adding TDs to the LNM count, 885 of 19 965 (4.4%) N1 patients were restaged as pN2, with worse outcomes than patients restaged as pN1 (3-year OS rate: 78.5%, 95%CI, 77.9%-79.1% vs 63.2%, 95%CI, 60.1%-66.5%, respectively; P < 0.0001). CONCLUSION: TDs are an independent prognostic factor for OS in colorectal cancer. The addition of TDs to LNM count improved the prognostic accuracy of tumor, node and metastasis staging.

Limitations in SELDI-TOF MS whole serum proteomic profiling with IMAC surface to specifically detect colorectal cancer.

BACKGROUND: Surface enhanced laser desorption and ionization time-of-flight mass spectrometry (SELDI-TOF-MS) analysis on serum samples was reported to be able to detect colorectal cancer (CRC) from normal or control patients. We carried out a validation study of a SELDI-TOF MS approach with IMAC surface sample processing to identify CRC. METHODS: A retrospective cohort of 338 serum samples including 154 CRCs, 67 control cancers and 117 non-cancerous conditions was profiled using SELDI-TOF-MS. RESULTS: No CRC "specific" classifier was found. However, a classifier consisting of two protein peaks separates cancer from non-cancerous conditions with high accuracy. CONCLUSION: In this study, the SELDI-TOF-MS-based protein expression profiling approach did not perform to identify CRC. However, this technique is promising in distinguishing patients with cancer from a non-cancerous population; it may be useful for monitoring recurrence of CRC after treatment.

Suppression of human colon tumor growth by adenoviral vector-mediated NK4 expression in an athymic mouse model.

AIM: To investigate the suppressive effects of adenoviral vector-mediated expression of NK4, an antagonist of hepatocyte growth factor (HGF), on human colon cancer in an athymic mouse model to explore the possibility of applying NK4 to cancer gene therapy. METHODS: A human colon tumor model was developed by subcutaneous implantation of tumor tissue formed by LS174T cells grown in athymic mice. Fifteen tumor-bearing mice were randomized into three groups (n = 5 in each group) at d 3 after tumor implantation and mice were injected intratumorally with phosphate-buffered saline (PBS) or with recombinant adenovirus expressing beta-galactosidase (Ad-LacZ) or NK4 (rvAdCMV/NK4) at a 6-d interval for total 5 injections in each mouse. Tumor sizes were measured during treatment to draw a tumor growth curve. At d 26 after the first treatment, all animals were sacrificed and the tumors were removed to immunohistochemically examine proliferating cell nuclear antigen (PCNA), microvessel density (represented by CD31), and apoptotic cells. In a separate experiment, 15 additional athymic mice were employed to develop a tumor metastasis model by intraperitoneal injection (ip) of LS174T cells. These mice were randomized into 3 groups (n = 5 in each group) at d 1 after injection and were treated by ip injection of PBS, or Ad-LacZ, or rvAdCMV/NK4 at a 6-d interval for total two injections in each mouse. All animals were sacrificed at d 14 and the numbers and weights of disseminated tumors within the abdominal cavity were measured. RESULTS: Growth of human colon tumors were significantly suppressed in the athymic mice treated with rvAdCMV/NK4 (2537.4 +/- 892.3 mm(3)) compared to those treated by either PBS (5175.2 +/- 1228.6 mm(3)) or Ad-LacZ (5578.8 +/- 1955.7 mm(3)) (P < 0.05). The tumor growth inhibition rate was as high as 51%. Immunohistochemical staining revealed a similar PCNA labeling index (75.1% +/- 11.2% in PBS group vs 72.8% +/- 7.6% in Ad-LacZ group vs 69.3% +/- 9.4% in rvAdCMV/NK4 group) in all groups, but significantly lower microvessel density (10.7 +/- 2.4 in rvAdCMV/NK4 group vs 25.6 +/- 3.8 in PBS group or 21.3 +/- 3.5 in Ad-LacZ group, P < 0.05), and a markedly higher apoptotic index (7.3% +/- 2.4% in rvAdCMV/NK4 group vs 2.6 +/- 1.1% in PBS group or 2.1% +/- 1.5% in Ad-LacZ group, P < 0.05) in the rvAdCMV/NK4 group compared to the two control groups. In the tumor metastasis model, the number and weight of disseminated tumors of mice treated with rvAdCMV/NK4 were much lower than those of the control groups (tumor number: 6.2 +/- 3.3 in rvAdCMV/NK4 group vs 22.9 +/- 7.6 in PBS group or 19.8 +/- 8.5 in Ad-LacZ group, P < 0.05; tumor weight: 324 +/- 176 mg in rvAdCMV/NK4 group vs 962 +/- 382 mg in PBS group or 1116 +/- 484 mg in Ad-LacZ group, P < 0.05). CONCLUSION: The recombinant adenovirus, rvAdCMV/NK4, can attenuate the growth of colon cancer in vivo, probably by suppressing angiogenesis and inducing tumor cell apoptosis, but not by direct suppression of tumor cell proliferation. Moreover, rvAdCMV/NK4 may inhibit peritoneal dissemination of colon cancer cells in a murine tumor metastasis model. These findings indicate that NK4 gene transfer may be an effective tool for the treatment of colon cancer.

Effects of adenoviral-mediated gene transduction of NK4 on proliferation, movement, and invasion of human colonic LS174T cancer cells in vitro.

AIM: To investigate the inhibitory effects of a recombinant adenovirus vector that expresses NK4, a truncated form of human hepatocyte growth factor (HGF), on human colonic adenocarcinoma cells in vitro to establish a basis for future NK4 gene cancer therapy. METHODS: Cells from the LS174T human colonic adenocarcinoma cell line were infected with recombinant adenovirus rvAdCMV/NK4 and the effects of the manipulation on tumor cell proliferation, scatter, migration, and basement membrane invasion were assessed. Cells infected with a recombinant adenovirus vector (Ad-LacZ) expressing beta-galactosidase served as the controls. RESULTS: We found that rvAdCMV/NK4 expression attenuated HGF-induced tumor cell scatter, migration, and basement membrane invasion (P<0.05), but did not inhibit tumor cell proliferation. CONCLUSION: HGF-induced LS174T tumor cell scatter, migration, and invasion can be antagonized by the recombinant NK4-expressing adenovirus.