Phase II study of neo-adjuvant chemotherapy for locally advanced gastric cancer

Background

Neoadjuvant chemotherapy improves survival of locally advanced gastric cancer patients. However, benefit is limited and the best regimen remains controversial.

Objectives

Our primary objective of this prospective, multicenter phase 2 study was to evaluate the pathological complete response rate (PCR) with 2 cycles of docetaxel and capecitabine.

Methods

To be eligible, patients had to have histologically documented gastric cancer, a ECOG performance status 0 or 1, T_3or4 N_any M₀ staging after oesophagogastroduodenoscopy (OGD), endoscopic ultrasound (EUS), CT scan of thorax and abdomen, and negative laparoscopic examination and peritoneal washing. Eligible patients received two cycles of intravenous docetaxel 60 mg/m² on day 1 and oral capecitabine 900 mg/m² two times per day from day 1 to day 14 every 3 weeks. We evaluated the response by CT scan and EUS. The patients underwent curative resection with D2 lymphadenectomy subsequently.

Results

18 patients were enrolled in the study: 66% were male and the median age was 60 years. 17 patients had T3 disease at diagnosis. There was no pCR noted. 4 patients had a partial response of 22% (95% CI: 7–42%), 8 patients had stable disease and 3 patients had disease progression. The median survival was 17.1 months with 3 long-term survivors after at least 3 years of follow-up. The treatment was well tolerated with neutropenia being the most common toxicity. We observed 22% grade III and 33% grade IV neutropenia, but no neutropenic fever or death was observed from chemotherapy.

Conclusion

Neo-adjuvant chemotherapy with docetaxel and capecitabine has limited activity against GC. More effective treatment regimens are needed urgently.

Trial registration number

NCT00414271.

miR-30-HNF4γ and miR-194-NR2F2 regulatory networks contribute to the upregulation of metaplasia markers in the stomach

OBJECTIVE

Intestinal metaplasia and spasmolytic polypeptide-expressing metaplasia (SPEM) are considered neoplastic precursors of gastric adenocarcinoma and are both marked by gene expression alterations in comparison to normal stomach. Since miRNAs are important regulators of gene expression, we sought to investigate the role of miRNAs on the development of stomach metaplasias.

DESIGN

We performed miRNA profiling using a quantitative reverse transcription-PCR approach on laser capture microdissected human intestinal metaplasia and SPEM. Data integration of the miRNA profile with a previous mRNA profile from the same samples was performed to detect potential miRNA-mRNA regulatory circuits. Transfection of gastric cancer cell lines with selected miRNA mimics and inhibitors was used to evaluate their effects on the expression of putative targets and additional metaplasia markers.

RESULTS

We identified several genes as potential targets of miRNAs altered during metaplasia progression. We showed evidence that HNF4γ (upregulated in intestinal metaplasia) is targeted by miR-30 and that miR-194 targets a known co-regulator of HNF4 activity, NR2F2 (downregulated in intestinal metaplasia). Intestinal metaplasia markers such as VIL1, TFF2 and TFF3 were downregulated after overexpression of miR-30a in a HNF4γ-dependent manner. In addition, overexpression of HNF4γ was sufficient to induce the expression of VIL1 and this effect was potentiated by downregulation of NR2F2.

CONCLUSIONS

The interplay of the two transcription factors HNF4γ and NR2F2 and their coordinate regulation by miR-30 and miR-194, respectively, represent a miRNA to transcription factor network responsible for the expression of intestinal transcripts in stomach cell lineages during the development of intestinal metaplasia.

Gastric tumour-derived ANGPT2 regulation by DARPP-32 promotes angiogenesis

OBJECTIVE

Overexpression of dopamine and cAMP-regulated phosphoprotein, Mr 32000 (DARPP-32), and its truncated isoform (t-DARPP) are associated with gastric tumorigenesis. Herein, we investigated the role of DARPP-32 proteins in regulating angiopoietin 2 (ANGPT2) and promoting tumour angiogenesis.

DESIGN

Quantitative real-time RT-PCR, immunoblotting, luciferase reporter, immunofluorescence, immunohistochemistry and angiogenesis assays were applied to investigate the regulation of angiogenesis by DARPP-32 proteins.

RESULTS

Overexpression of DARPP-32 significantly increased the mRNA and protein levels of ANGPT2 in gastric cancer cells. The overexpression of DARPP-32 T34A mutant or the N-terminal truncated isoform, t-DARPP, led to similar effects ruling out the T34-dependent regulation of protein phosphatase 1 activity in regulating ANGPT2. DARPP-32 proteins induced a secreted form of ANGPT2, which was detectable in the media, functionally active, and able to induce angiogenesis, measured by the human umbilical vein endothelial cells tube formation assay. Antibody blocking of the secreted ANGPT2 abrogated its function. To identify the mechanism by which DARPP-32 regulates ANGPT2, we examined the activities of NF-κB and signal transducer and activator of transcription 3 (STAT3), known regulators of angiogenesis. The results ruled out NF-κB and showed induction of STAT3 phosphorylation, activation and nuclear localisation. Inhibition or knockdown of STAT3 significantly attenuated the induction of ANGPT2 by DARPP-32 proteins. In vivo xenograft models demonstrated that overexpression of DARPP-32 promotes angiogenesis and tumour growth. Analyses of human gastric cancer tissues showed a strong correlation between DARPP-32 and ANGPT2.

CONCLUSIONS

Our novel findings establish the role of DARPP-32-STAT3 axis in regulating ANGPT2 in cancer cells to promote angiogenesis and tumorigenesis.