BZD9L1 benzimidazole analogue hampers colorectal tumor progression by impeding angiogenesis

BACKGROUND

The development of new vasculatures (angiogenesis) is indispensable in supplying oxygen and nutrients to fuel tumor growth. Epigenetic dysregulation in the tumor vasculature is critical to colorectal cancer (CRC) progression. Sirtuin (SIRT) enzymes are highly expressed in blood vessels. BZD9L1 benzimidazole analogue is a SIRT 1 and 2 inhibitor with reported anticancer activities in CRC. However, its role has yet to be explored in CRC tumor angiogenesis.

AIM

To investigate the anti-angiogenic potential of BZD9L1 on endothelial cells (EC) in vitro, ex vivo and in HCT116 CRC xenograft in vivo models.

METHODS

EA.hy926 EC were treated with half inhibitory concentration (IC₅₀) (2.5 μM), IC₅₀ (5.0 μM), and double IC₅₀ (10.0 μM) of BZD9L1 and assessed for cell proliferation, adhesion and SIRT 1 and 2 protein expression. Next, 2.5 μM and 5.0 μM of BZD9L1 were employed in downstream in vitro assays, including cell cycle, cell death and sprouting in EC. The effect of BZD9L1 on cell adhesion molecules and SIRT 1 and 2 were assessed via real-time quantitative polymerase chain reaction (qPCR). The growth factors secreted by EC post-treatment were evaluated using the Quantibody Human Angiogenesis Array. Indirect co-culture with HCT116 CRC cells was performed to investigate the impact of growth factors modulated by BZD9L1-treated EC on CRC. The effect of BZD9L1 on sprouting impediment and vessel regression was determined using mouse choroids. HCT116 cells were also injected subcutaneously into nude mice and analyzed for the outcome of BZD9L1 on tumor necrosis, Ki67 protein expression indicative of proliferation, cluster of differentiation 31 (CD31) and CD34 EC markers, and SIRT 1 and 2 genes via hematoxylin and eosin, immunohistochemistry and qPCR, respectively.

RESULTS

BZD9L1 impeded EC proliferation, adhesion, and spheroid sprouting through the downregulation of intercellular adhesion molecule 1, vascular endothelial cadherin, integrin-alpha V, SIRT1 and SIRT2 genes. The compound also arrested the cells at G1 phase and induced apoptosis in the EC. In mouse choroids, BZD9L1 inhibited sprouting and regressed sprouting vessels compared to the negative control. Compared to the negative control, the compound also reduced the protein levels of angiogenin, basic fibroblast growth factor, platelet-derived growth factor and placental growth factor, which then inhibited HCT116 CRC spheroid invasion in co-culture. In addition, a significant reduction in CRC tumor growth was noted alongside the downregulation of human SIRT1 (hSIRT1), hSIRT2, CD31, and CD34 EC markers and murine SIRT2 gene, while the murine SIRT1 gene remained unaffected, compared to vehicle control. Histology analyses revealed that BZD9L1 at low (50 mg/kg) and high (250 mg/kg) doses reduced Ki-67 protein expression, while BZD9L1 at the high dose diminished tumor necrosis compared to vehicle control.

CONCLUSION

These results highlighted the anti-angiogenic potential of BZD9L1 to reduce CRC tumor progression. Furthermore, together with previous anticancer findings, this study provides valuable insights into the potential of BZD9L1 to co-target CRC tumor vasculatures and cancer cells via SIRT1 and/or SIRT2 down-regulation to improve the therapeutic outcome.

Oral vitamin D supplementation induces transcriptomic changes in rectal mucosa that are linked to anti-tumour effects

BACKGROUND

The risk for several common cancers is influenced by the transcriptomic landscape of the respective tissue-of-origin. Vitamin D influences in vitro gene expression and cancer cell growth. We sought to determine whether oral vitamin D induces beneficial gene expression effects in human rectal epithelium and identify biomarkers of response.

METHODS

Blood and rectal mucosa was sampled from 191 human subjects and mucosa gene expression (HT12) correlated with plasma vitamin D (25-OHD) to identify differentially expressed genes. Fifty subjects were then administered 3200IU/day oral vitamin D3 and matched blood/mucosa resampled after 12 weeks. Transcriptomic changes (HT12/RNAseq) after supplementation were tested against the prioritised genes for gene-set and GO-process enrichment. To identify blood biomarkers of mucosal response, we derived receiver-operator curves and C-statistic (AUC) and tested biomarker reproducibility in an independent Supplementation Trial (BEST-D).

RESULTS

Six hundred twenty-nine genes were associated with 25-OHD level (P < 0.01), highlighting 453 GO-term processes (FDR<0.05). In the whole intervention cohort, vitamin D supplementation enriched the prioritised mucosal gene-set (upregulated gene-set P < 1.0E-07; downregulated gene-set P < 2.6E-05) and corresponding GO terms (P = 2.90E-02), highlighting gene expression patterns consistent with anti-tumour effects. However, only 9 individual participants (18%) showed a significant response (NM gene-set enrichment P < 0.001) to supplementation. Expression changes in HIPK2 and PPP1CC expression served as blood biomarkers of mucosal transcriptomic response (AUC=0.84 [95%CI 0.66-1.00]) and replicated in BEST-D trial subjects (HIPK2 AUC=0.83 [95%CI 0.77-0.89]; PPP1CC AUC=0.91 [95%CI 0.86-0.95]).

CONCLUSIONS

Higher plasma 25-OHD correlates with rectal mucosa gene expression patterns consistent with anti-tumour effects, and this beneficial signature is induced by short-term vitamin D supplementation. Heterogenous gene expression responses to vitamin D may limit the ability of randomised trials to identify beneficial effects of supplementation on CRC risk. However, in the current study blood expression changes in HIPK2 and PPP1CC identify those participants with significant anti-tumour transcriptomic responses to supplementation in the rectum. These data provide compelling rationale for a trial of vitamin D and CRC prevention using easily assayed blood gene expression signatures as intermediate biomarkers of response.

Low plasma vitamin D is associated with adverse colorectal cancer survival after surgical resection, independent of systemic inflammatory response

OBJECTIVE

We assessed the effect of surgical resection of colorectal cancer (CRC) on perioperative plasma vitamin D (25OHD) and C-reactive protein (CRP) level. We investigated the relationship between circulating vitamin D level and CRC survival.

DESIGN

We sequentially sampled 92 patients undergoing CRC resection, and measured plasma 25OHD and CRP. For survival analyses, we assayed 25OHD and CRP in two temporally distinct CRC patient cohorts (n=2006, n=2100) and investigated the association between survival outcome, circulating vitamin D and systemic inflammatory response.

RESULTS

Serial sampling revealed a postoperative fall (mean 17.3 nmol/L; p=3.6e-9) in plasma 25OHD (nadir days 1-2). CRP peaked 3-5 days postoperatively (143.1 mg/L; p=1.4e-12), yet the postoperative fall in 25OHD was independent of CRP. In cohort analyses, 25OHD was lower in the 12 months following operation (mean=48.8 nmol/L) than preoperatively (54.8 nmol/L; p=1.2e-5) recovering after 24 months (52.2 nmol/L; p=0.002). Survival analysis in American Joint Committee on Cancer stages I-III demonstrated associations between 25OHD tertile and CRC mortality (HR=0.69; 95% CI 0.46 to 0.91) and all-cause mortality (HR=0.68; 95% CI 0.50 to 0.85), and was independent of CRP. We observed interaction effects between plasma 25OHD and rs11568820 genotype (functional VDR polymorphism) with a strong protective effect of higher 25OHD only in patients with GG genotype (HR=0.51; 95% CI 0.21 to 0.81). We developed an online tool for predicted survival (https://apps.igmm.ed.ac.uk/mortalityCalculator/) that incorporates 25OHD with clinically useful predictive performance (area under the curve 0.77).

CONCLUSIONS

CRC surgery induces a fall in circulating 25OHD. Plasma 25OHD level is a prognostic biomarker with low 25OHD associated with poorer survival, particularly in those with rs11568820 GG genotype. A randomised trial of vitamin D supplementation after CRC surgery has compelling rationale.