Downregulation of SPARC expression decreases gastric cancer cellular invasion and survival

Background

Secreted protein acidic and rich in cysteine (SPARC) plays a key role in the development of many tissues and organ types. Aberrant SPARC expression was found in a wide variety of human cancers, contributes to tumor development. Because SPARC was found to be overexpressed in human gastric cancer tissue, we therefore to explore the expression of SPARC in gastric cancer lines and the carcinogenic mechanisms.

Methods

SPARC expression was evaluated in a panel of human gastric cancer cell lines. MGC803 and HGC 27 gastric cancer cell lines expressing high level of SPARC were transiently transfected with SPARC-specific small interfering RNAs and subsequently evaluated for effects on invasion and proliferation.

Results

Small interfering RNA-mediated knockdown of SPARC in MGC803 and HGC 27 gastric cancer cells dramatically decreased their invasion. Knockdown of SPARC was also observed to significantly increase the apoptosis of MGC803 and HGC 27 gastric cancer cells compared with control transfected group.

Conclusions

Our data showed that downregulating of SPARC inhibits invasion and growth of human gastric cancer cells. Thus, targeting of SPARC could be an effective therapeutic approach against gastric cancer.     

Deregulated microRNAs in gastric cancer tissue-derived mesenchymal stem cells: novel biomarkers and a mechanism for gastric cancer

Background:

MicroRNAs (miRNAs) are involved in gastric cancer development and progression. However, the expression and role of miRNAs in gastric cancer stromal cells are still unclear.

Methods:

The miRNAs differentially expressed in gastric cancer tissue-derived mesenchymal stem cells (GC-MSCs) relative to adjacent non-cancerous tissue-derived MSCs (GCN-MSCs) and in cancer tissues relative to adjacent non-cancerous tissues were screened using miRNA microarray and validated by quantitative RT–PCR. The impact of GC-MSCs on HGC-27 cells was observed in vitro using colony formation and transwell assays, and these cells were subcutaneously co-injected into mice to assess tumour growth in vivo. Exogenous downregulation of miR-221 expression in cells was achieved using an miRNA inhibitor.

Results:

miR-214, miR-221 and miR-222 were found to be commonly upregulated in GC-MSCs and cancer tissues. Their levels were tightly associated with lymph node metastasis, venous invasion and the TNM stage. Gastric cancer tissue-derived mesenchymal stem cells significantly promoted HGC-27 growth and migration and increased the expression of miR-221 via paracrine secretion, and the targeted inhibition of miR-221 in GC-MSCs could block its tumour-supporting role. GC-MSC-derived exosomes were found to deliver miR-221 to HGC-27 cells and promoted their proliferation and migration.

Conclusions:

Gastric cancer tissue-derived mesenchymal stem cells favour gastric cancer progression by transferring exosomal miRNAs to gastric cancer cells, thus providing a novel mechanism for the role of GC-MSCs and new biomarkers for gastric cancer.     

Microtubule-associated protein tau facilitates the targeted killing of proliferating cancer cells in vitro and in a xenograft mouse tumour model in vivo

Background:

Antibody drug conjugates (ADCs) and immunotoxins (ITs) are promising anticancer immunotherapeutics. Despite their encouraging performance in clinical trials, both ADCs and ITs often suffer from disadvantages such as stoichiometrically undefined chemical linkage of the cytotoxic payload (ADCs) and the potential immunogenicity of toxins derived from bacteria and plants (ITs).

Methods:

Human microtubule-associated protein tau (MAP) was cloned in-frame with human EGF, expressed in E. coli and purified by standard chromatographic methods. The in vitro activity was confirmed by flow cytometry, cell viability assays and tubulin polymerisation assay. The in vivo efficacy was demonstrated using noninvasive far-red in vivo imaging.

Results:

The EGF-MAP selectively induced apoptosis in EGFR-overexpressing proliferating cancer cells through stabilisation of microtubules. Nonproliferating cells were not affected, demonstrating superior selectivity of EGF-MAP for cancer cells. The EGF-MAP was well tolerated at high doses in mice compared with the ETA''-based control. The in vivo efficacy of EGF-MAP was demonstrated in a tumour xenograft mouse model.

Conclusion:

Our data indicate the general mechanism of action for a new class of human immunotherapeutic reagents suitable for the treatment of cancer. This approach combines the binding specificity of targeting ligands with the selective cytotoxicity of MAP towards proliferating cells.     

A novel oncolytic viral therapy and imaging technique for gastric cancer using a genetically engineered vaccinia virus carrying the human sodium iodide symporter

Background

Gastric cancers have poor overall survival despite recent advancements in early detection methods, endoscopic resection techniques, and chemotherapy treatments. Vaccinia viral therapy has had promising therapeutic potential for various cancers and has a great safety profile. We investigated the therapeutic efficacy of a novel genetically-engineered vaccinia virus carrying the human sodium iodide symporter (hNIS) gene, GLV-1 h153, on gastric cancers and its potential utility for imaging with ^99mTc pertechnetate scintigraphy and ¹²⁴I positron emission tomography (PET).

Methods

GLV-1 h153 was tested against five human gastric cancer cell lines using cytotoxicity and standard viral plaque assays. In vivo, subcutaneous flank tumors were generated in nude mice with human gastric cancer cells, MKN-74. Tumors were subsequently injected with either GLV-1 h153 or PBS and followed for tumor growth. ^99mTc pertechnetate scintigraphy and ¹²⁴I microPET imaging were performed.

Results

GFP expression, a surrogate for viral infectivity, confirmed viral infection by 24 hours. At a multiplicity of infection (MOI) of 1, GLV-1 h153 achieved > 90% cytotoxicity in MNK-74, OCUM-2MD3, and AGS over 9 days, and >70% cytotoxicity in MNK- 45 and TMK-1. In vivo, GLV-1 h153 was effective in treating xenografts (p < 0.001) after 2 weeks of treatment. GLV-1 h153-infected tumors were readily imaged by ^99mTc pertechnetate scintigraphy and ¹²⁴I microPET imaging 2 days after treatment.

Conclusions

GLV-1 h153 is an effective oncolytic virus expressing the hNIS protein that can efficiently regress gastric tumors and allow deep-tissue imaging. These data encourages its continued investigation in clinical settings.     

FAT4 functions as a tumour suppressor in gastric cancer by modulating Wnt/β-catenin signalling

Background:

FAT4, a cadherin-related protein, was shown to function as a tumour suppressor; however, its role in human gastric cancer remains largely unknown. Here, we investigated the role of FAT4 in gastric cancer and examined the underlying molecular mechanisms.

Methods:

The expression of FAT4 was evaluated by immunohistochemistry, western blotting, and qRT–PCR in relation to the clinicopathological characteristics of gastric cancer patients. The effects of FAT4 silencing on cell proliferation, migration, and invasion were assessed by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium) assay, and migration and invasion assays in gastric cancer cell lines in vitro and in a mouse xenograft model in vivo.

Results:

Downregulation of FAT4 expression in gastric cancer tissues compared with adjacent normal tissues was correlated with lymph-node metastasis and poor survival. Knockdown of FAT4 promoted the growth and invasion of gastric cancer cells via the activation of Wnt/β-catenin signalling, and induced epithelial-to-mesenchymal transition (EMT) in gastric cancer cells, as demonstrated by the upregulation and downregulation of mesenchymal and epithelial markers. Silencing of FAT4 promoted tumour growth and metastasis in a gastric cancer xenograft model in vivo.

Conclusions:

FAT4 has a tumour suppressor role mediated by the modulation of Wnt/β-catenin signalling, providing potential novel targets for the treatment of gastric cancer.     

Monitoring response to cytostatic cisplatin in a HER2(+) ovary cancer model by MRI and in vitro and in vivo MR spectroscopy

Background:

Limited knowledge is available on alterations induced by cytostatic drugs on magnetic resonance spectroscopy (MRS) and imaging (MRI) parameters of human cancers, in absence of apoptosis or cytotoxicity. We here investigated the effects of a cytostatic cisplatin (CDDP) treatment on ¹H MRS and MRI of HER2-overexpressing epithelial ovarian cancer (EOC) cells and in vivo xenografts.

Methods:

High-resolution MRS analyses were performed on in vivo passaged SKOV3.ip cells and cell/tissue extracts (16.4 or 9.4 T). In vivo MRI/MRS quantitative analyses (4.7 T) were conducted on xenografts obtained by subcutaneous implantation of SKOV3.ip cells in SCID mice. The apparent diffusion coefficient (ADC) and metabolite levels were measured.

Results:

CDDP-induced cytostatic effects were associated with a metabolic shift of cancer cells towards accumulation of MRS-detected neutral lipids, whereas the total choline profile failed to be perturbed in both cultured cells and xenografts. In vivo MRI examinations showed delayed tumour growth in the CDDP-treated group, associated with early reduction of the ADC mean value.

Conclusion:

This study provides an integrated set of information on cancer metabolism and physiology for monitoring the response of an EOC model to a cytostatic chemotherapy, as a basis for improving the interpretation of non-invasive MR examinations of EOC patients.     

Human monoclonal antibodies targeting carbonic anhydrase IX for the molecular imaging of hypoxic regions in solid tumours

Background:

Hypoxia, which is commonly observed in areas of primary tumours and of metastases, influences response to treatment. However, its characterisation has so far mainly been restricted to the ex vivo analysis of tumour sections using monoclonal antibodies specific to carbonic anhydrase IX (CA IX) or by pimonidazole staining, after the intravenous administration of this 2-nitroimidazole compound in experimental animal models.

Methods:

In this study, we describe the generation of high-affinity human monoclonal antibodies (A3 and CC7) specific to human CA IX, using phage technology.

Results:

These antibodies were able to stain CA IX ex vivo and to target the cognate antigen in vivo. In one of the two animal models of colorectal cancer studied (LS174T), CA IX imaging closely matched pimonidazole staining, with a preferential staining of tumour areas characterised by little vascularity and low perfusion. In contrast, in a second animal model (SW1222), distinct staining patterns were observed for pimonidazole and CA IX targeting. We observed a complementary pattern of tumour regions targeted in vivo by the clinical-stage vascular-targeting antibody L19 and the anti-CA IX antibody A3, indicating that a homogenous pattern of in vivo tumour targeting could be achieved by a combination of the two antibodies.

Conclusion:

The new human anti-CA IX antibodies are expected to be non-immunogenic in patients with cancer and may serve as broadly applicable reagents for the non-invasive imaging of hypoxia and for pharmacodelivery applications.     

In vivo Molecular targeting effects of anti-Sp17- ICG-Der-02 on hepatocellular carcinoma evaluated by an optical imaging system

Background

As the expression of human sperm protein 17 (Sp17) in normal tissue is limited and the function is obscure, its aberrant expression in malignant tumors makes it to be a candidated molecular marker for tumor imaging diagnosis and targeting therapy of the diseases.The aim of this research is to evaluate the targeting effects of anti-sperm protein 17 monoclonal antibody (anti-Sp17) on cancer in vivo and investigate its usefulness as a reagent for molecular imaging diagnosis.

Methods

Immunohistochemistry was used to identify the expression of Sp17 in a hepatocellular carcinoma cell line and tumor xenograft specimens. A near infrared fluorescence dye, ICG-Der-02, was covalently linked to anti-Sp17 for in vivo imaging. The immuno-activity of the anti-Sp17-ICG-Der-02 complex was tested in vitro by ELISA; it was then injected into tumor-bearing nude mice through the caudal vein to evaluate its tumor targeting effect by near infrared imaging system.

Results

Overexpression of Sp17 on the surface of the hepatocellular carcinoma cell line SMMC-7721 was demonstrated. Anti-Sp17-ICG-Der-02 with immuno-activity was successfully synthesized. The immuno-activity and photo stability of anti-Sp17- ICG-Der-02 showed good targeting capability for Sp17 expressing tumor models (SMMC-7721) in vivo, and its accumulation in the tumor lasted for at least 7 days.

Conclusions

Anti-Sp17 antibody targeted and accumulated in Sp17 positive tumors in vivo, which demonstrated its capability of serving as a diagnostic reagent.     

Polymeric nanocomposites loaded with fluoridated hydroxyapatite Ln3+ (Ln = Eu or Tb)/iron oxide for magnetic targeted cellular imaging

Objective

To fabricate polymeric nanocomposites with excellent photoluminescence, magnetic properties, and stability in aqueous solutions, in order to improve specificity and sensitivity of cellular imaging under a magnetic field.

Methods

Fluoridated Ln³⁺-doped HAP (Ln³⁺-HAP) NPs and iron oxides (IOs) can be encapsulated with biocompatible polymers via a modified solvent exaction/evaporation technique to prepare polymeric nanocomposites with fluoridated Ln³⁺-HAP/iron oxide. The nanocomposites were characterized for surface morphology, fluorescence spectra, magnetic properties and in vitro cytotoxicity. Magnetic targeted cellular imaging of such nanocomposites was also evaluated with confocal laser scanning microscope using A549 cells with or without magnetic field.

Results

The fabricated nanocomposites showed good stability and excellent luminescent properties, as well as low in vitro cytotoxicity, indicating that the nanocomposites are suitable for biological applications. Nanocomposites under magnetic field achieved much higher cellular uptake via an energy-dependent pathway than those without magnetic field.

Conclusion

The nanocomposites fabricated in this study will be a promising tool for magnetic targeted cellular imaging with improved specificity and enhanced selection.KEYWORDS : Cancer, cellular imaging, nanocomposites, magnetic targeted, hydroxyapatite (HAP) doped with rare earth     

Ewing sarcoma dissemination and response to T-cell therapy in mice assessed by whole-body magnetic resonance imaging

Background:

Novel treatment strategies in Ewing sarcoma include targeted cellular therapies. Preclinical in vivo models are needed that reflect their activity against systemic (micro)metastatic disease.

Methods:

Whole-body magnetic resonance imaging (WB-MRI) was used to monitor the engraftment and dissemination of human Ewing sarcoma xenografts in mice. In this model, we evaluated the therapeutic efficacy of T cells redirected against the Ewing sarcoma-associated antigen G_D2 by chimeric receptor engineering.

Results:

Of 18 mice receiving intravenous injections of VH-64 Ewing sarcoma cells, all developed disseminated tumour growth detectable by WB-MRI. All mice had lung tumours, and the majority had additional manifestations in the bone, soft tissues, and/or kidney. Sequential scans revealed in vivo growth of tumours. Diffusion-weighted whole-body imaging with background signal suppression effectively visualised Ewing sarcoma growth in extrapulmonary sites. Animals receiving G_D2-targeted T-cell therapy had lower numbers of pulmonary tumours than controls, and the median volume of soft tissue tumours at first detection was lower, with a tumour growth delay over time.

Conclusion:

Magnetic resonance imaging reliably visualises disseminated Ewing sarcoma growth in mice. G_D2-retargeted T cells can noticeably delay tumour growth and reduce pulmonary Ewing sarcoma manifestations in this aggressive disease model.     

Synergistic inhibitory effect of wogonin and low-dose paclitaxel on gastric cancer cells and tumor xenografts

Objective：To investigate the synergistic inhibitory effects of wogonin （WOG） and chemotherapeutic drugs on growth of gastric cancer cells and tumor xenografts.Methods：The IC50 values of WOG,cisplatin （CDDP） and paclitaxel （PTX） in four gastric cancer cell lines were determined by MTS assay.Hoechst staining and the median effect method of Chou-Talalay were used to assess the apoptosis of cells and the interaction of two drugs,respectively.BGC-823-derived xenografts in nude mice were established to investigate the effects of WOG combined with chemotherapeutic drugs in vivo.Results：WOG,CDDP and PTX inhibited the growth of BGC-823,MGC-803,MKN-45 and HGC-27 gastric cancer cells in a dose-dependent manner.WOG combined with CDDP or PTX synergistically inhibited the growth of all gastric cancer cell lines in vitro.In BGC-823,MGC-803,HGC-27 and MKN-45 cell lines,synergisms between WOG and PTX were shown when the fraction affected （Fa） values were ＜0.45,＜0.90,＜0.85 and ＜0.60.While WOG and CDDP had a synergistic inhibitory.effect when the Fa values were ＞0,＞0,＞0.65 and ＞0.10.From the results of in vivo experiments using tumor xenografts,WOG and low-dose PTX showed better efficacy than either drug alone.The inhibitory percentages of tumor weight were 61.58％,20.29％,and 22.28％ for the combination,WOG-alone,and low-dose PTX-alone groups,respectively.Notably,WOG combined with CDDP displayed very high toxicity.Conclusions：A synergistic inhibitory effect on growth was observed when WOG was combined with low-dose PTX in gastric cancer cells and tumor xenografts.These findings provide evidence for the design of a clinical trial to test the combination of WOG with low-dose PTX in human gastric cancer.     

Huachansu suppresses human bladder cancer cell growth through the Fas/Fasl and TNF- alpha/TNFR1 pathway in vitro and in vivo

Background

Huachansu (HCS), a class of toxic steroids extracted from toad venom, which has been shown to be a valuable anticancer drug in many kinds of cancers. However, the effect of HCS on bladder cancer has not been elucidated. In this study, we focused on the antitumor activities and related mechanisms of HCS on bladder cancer in vitro and in vivo.

Methods

Cell viability of T24, EJ, RT-4, SV-HUC-1 cells after HCS treatment was measured by MTS, whereas the changes of cell morphology were observed by transmission electron microscopy. The early apoptosis induced by HCS was evaluated by flow cytometry, and the expression level of apoptosis-related molecules (Bax, Bcl-2, XIAP, PARP, cleaved-Caspases 3, 8, 9) was detected using Western blot. We then evaluated the impact of HCS on the expression of Fas/Fasl, TNF- alpha/TNFR1, and the activation of NF-Kappa B pathway, and furthermore the effect of these pathways in HCS induced-apoptosis were also detected. At last, xenograft tumor in nude mice was used to further investigate the antitumor effect of HCS in vivo.

Results

Our results showed that HCS could efficiently inhibit proliferation and induce apoptosis in human bladder cancer cell lines. The expression of Fas, Fasl, TNF- alpha were all elevated at both mRNA and protein level after HCS treatment. Furthermore, down regulation of TNF- alpha, TNFR1, Fas or inhibition of Fas/Fasl interaction decreased the relative number of death cells induced by HCS. In vivo, HCS treatment significantly suppressed tumor growth and induced apoptosis in xenografts tumor in nude mice.

Conclusions

HCS could efficiently inhibit proliferation and induce apoptosis in human bladder cancer cells in vitro and in vivo, which is largely mediated by Fas/Fasl and TNF- alpha/TNFR1 pathway.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-015-0134-9) contains supplementary material, which is available to authorized users.     

Overexpression of stathmin1 in the diffuse type of gastric cancer and its roles in proliferation and migration of gastric cancer cells

Background:

Stathmin1 is a microtubule-regulating protein that has an important role in the assembly and disassembly of the mitotic spindle. The roles of stathmin1 in carcinogenesis of various cancers, including prostate and breast cancer, have been explored. However, its expression and roles in gastric cancer have not yet been described.

Methods:

Stathmin1 expression in paraffin-embedded tissue sections from 226 patients was analysed by immunohistochemistry. Roles of stathmin1 were studied using a specific small interfering RNA (siRNA).

Results:

The expression of stathmin1 was positively correlated with lymph node metastasis, TNM stages and vascular invasion, and negatively with recurrence-free survival, in the diffuse type of gastric cancer. The median recurrence-free survival in patients with a negative and positive expression of stathmin1 was 17.0 and 7.0 months, respectively (P=0.009). When the expression of stathmin1 was knocked down using siRNA, the proliferation, migration and invasion of poorly differentiated gastric cancer cells in vitro were significantly inhibited. Moreover, stathmin1 siRNA transfection significantly slowed the growth of xenografts in nude mice.

Conclusion:

These results suggest that stathmin1 can be a good prognostic factor for recurrence-free survival rate and is a therapeutic target in diffuse-type gastric cancer.     

Lack of correlation of stem cell markers in breast cancer stem cells

Background:

Various markers are used to identify the unique sub-population of breast cancer cells with stem cell properties. Whether these markers are expressed in all breast cancers, identify the same population of cells, or equate to therapeutic response is controversial.

Methods:

We investigated the expression of multiple cancer stem cell markers in human breast cancer samples and cell lines in vitro and in vivo, comparing across and within samples and relating expression with growth and therapeutic response to doxorubicin, docetaxol and radiotherapy.

Results:

CD24, CD44, ALDH and SOX2 expression, the ability to form mammospheres and side-population cells are variably present in human cancers and cell lines. Each marker identifies a unique rather than common population of cancer cells. In vivo, cells expressing these markers are not specifically localized to the presumptive stem cell niche at the tumour/stroma interface. Repeated therapy does not consistently enrich cells expressing these markers, although ER-negative cells accumulate.

Conclusions:

Commonly employed methods identify different cancer cell sub-populations with no consistent therapeutic implications, rather than a single population of cells. The relationships of breast cancer stem cells to clinical parameters will require identification of specific markers or panels for the individual cancer.     

Clinicopathological and prognostic differences between mucinous gastric carcinoma and signet-ring cell carcinoma

Objective: To analyze the differences in clinicopathologic characteristics and prognosis between mucinous gastric carcinoma (MGC) and signet-ring cell carcinoma (SRCC). Methods: Clinicopathologic and prognostic data of 1,637 patients with histologically confirmed MGC or SRCC who received surgical operations in the Department of Gastroenterological Surgery, Beijing Cancer Hospital between December 2004 and December 2009 were retrospectively collected and analyzed. The clinicopathological features were analyzed statistically using χ 2 test. Survival was analyzed using the Kaplan-Meier method and multivariate analysis of Cox proportional hazards regression model (backward, stepwise). Results: A total of 181 patients with gastric cancer (74 MGC, 107 SRCC) were included. MGC, when compared with SRCC, was featured by senile patients, stage III and IV, upper third stomach, large tumor size, positive lymph node metastasis, and positive lymphatic vascular invasion (P<0.05). The overall 5-year survival rate showed no difference between the two groups (48.8% vs. 44.8%, P>0.05). However, the survival rate for MGC patients was significant lower than that for SRCC patients when compared among the age <60 years, negative distant metastasis, and tumor localized at upper third stomach (P<0.05). Multivariate Cox proportional hazards models revealed that distant metastasis was a significant independent prognostic indicator in MGC group, and lymph node metastasis and distant metastasis was significant independent prognostic indicators in SRCC group. Conclusions: While compared with SRCC, MGC is associated with a more aggressive tumor biologic behavior. There is no statistically significant difference in distant metastasis, an independent prognostic indicator for both MGC and SRCC, which might be the reason for no significant difference of the overall survival rate between the patients with MGC and SRCC.     

PI3K/Akt signalling is required for the attachment and spreading, and growth in vivo of metastatic scirrhous gastric carcinoma

Background:

PI3K/Akt (PKB) pathway has been shown in several cell types to be activated by ligands to cell surface integrins, leading to the metastasis of tumour cells. The signalling pathways involved in the metastatic spread of human scirrhous gastric carcinoma cells have not been defined.

Methods:

The role of the PI3K/Akt pathway in an extensive peritoneal-seeding cell line, OCUM-2MD3 and a parental cell line, OCUM-2M, was investigated by assessing in vitro adhesion and spreading assay, and in vivo peritoneal metastatic model. We also examined the correlation of PI3K/Akt pathway with integrin signals by immunoprecipitations, using cells by transfection with mutant p85 (Δp85).

Results:

Adhesiveness and spreading of OCUM-2MD3 cells on collagen type IV was significantly decreased by PI3K inhibitors and expression of mutant p85, but not by inhibitors of protein kinase C (PKC) or extracellular signal-regulated kinase (ERK). Immunoprecipitation studies indicated that the PI3K/Akt pathway was associated with integrin signalling through Src and vinculin. In an in vivo experimental metastasis model, p85 inhibition reduced peritoneal metastasis of OCUM-2MD3 cells.

Conclusion:

PI3K/Akt signalling may be required for integrin-dependent attachment and spreading of scirrhous gastric carcinoma cells, and would be translated into generating better strategies to optimise their use in cancer clinical trials.     

ALKBH3, a human AlkB homologue, contributes to cell survival in human non-small-cell lung cancer

Background:

We have demonstrated for the first time that a novel human AlkB homologue, ALKBH3, contributes to prostate cancer development, but its clinical and biological roles in lung cancer remain unclear.

Methods:

Expression of both mRNA and protein of PCA-1 was examined by RT–PCR and western blotting. We also assessed association with senescence and in vivo ALKBH3 treatment on orthotopic tumour cell inoculation, and analysed it clinicopathologically.

Results:

We have since found novel biological roles for ALKBH3 in human lung cancers, particularly in adenocarcinoma. Our immunohistochemical analysis of human adenocarcinomas and squamous cell carcinomas of the lung not only showed overexpression of ALKBH3 in these tumours but the percentage of cells positive for ALKBH3 also correlated statistically to recurrence-free survival in adenocarcinoma. Knockdown of ALKBH3 by siRNA transfection induced expression of p21^WAF1/Cip1 and p27^Kip1 in the human lung adenocarcinoma cell line A549, resulting in cell cycle arrest, senescence and strong suppression of cell growth in vitro. In vivo, peritoneal tumour growth and dissemination was inhibited in nude mice, previously inoculated with the A549 cell line, by intraperitoneal injection of ALKBH3 siRNA + atelocollagen, as demonstrated by the reduction in both number and diameter of tumours developing in the peritoneum.

Conclusion:

We suggest that ALKBH3 contributes significantly to cancer cell survival and may be a therapeutic target for human adenocarcinoma of the lung.