Racial disparities in the association between diabetes mellitus-associated polymorphic locus rs4430796 of the HNF1β gene and prostate cancer: a systematic review and meta-analysis

Prostate cancer genetic propensity risk score may modify the association between this tumour and type 2 diabetes mellitus (MCC-Spain study)

BACKGROUND

Some studies have reported an inverse association between type 2 diabetes mellitus (T2DM) and prostate cancer (PCa), but results on this issue are still inconsistent. In this study, we evaluate whether this heterogeneity might be related to differences in this relationship by tumour or by individual genetic susceptibility to PCa.

METHODS

We studied 1047 incident PCa cases and 1379 randomly selected controls, recruited in 7 Spanish provinces for the population-based MCC-Spain case-control. Tumour were classified by aggressiveness according to the International Society of Urological Pathology (ISUP), and we constructed a PCa polygenic risk score (PRS) as proxy for genetic susceptibility. The epidemiological questionnaire collected detailed self-reported data on T2DM diagnosis and treatment. The association between T2DM status and PCa was studied by fitting mixed logistic regression models, and, for its association by aggressiveness of PCa, with multinomial logistic regression models. To evaluate the possible modulator role of PRS in this relationship, we included the corresponding interaction term in the model, and repeated the analysis stratified by PRS tertiles.

RESULTS

Globally, our results showed an inverse association between T2DM and overall PCa limited to grade 1 tumours (OR_ISUP = 1: 0.72; 95% CI: 0.53-0.98), which could be compatible with a detection bias. However, PCa risk also varied with duration of diabetes treatment -inversely to metformin and positively with insulin-, without differences by aggressiveness. When we considered genetic susceptibility, T2DM was more strongly associated with lower PCa risk in those with lower PRS (OR_{tertile 1}: 0.31; 95% CI: 0.11-0.87), independently of ISUP grade.

CONCLUSIONS

Our findings reinforce the need to include aggressiveness and susceptibility of PCa, and T2DM treatments in the study of the relationship between both diseases.

The association of diabetes with risk of prostate cancer defined by clinical and molecular features

BACKGROUND

To prospectively examine the association between diabetes and risk of prostate cancer defined by clinical and molecular features.

METHODS

A total of 49,392 men from the Health Professionals Follow-up Study (HPFS) were followed from 1986 to 2014. Data on self-reported diabetes were collected at baseline and updated biennially. Clinical features of prostate cancer included localised, advanced, lethal, low-grade, intermediate-grade, and high-grade. Molecular features included TMPRSS2: ERG and PTEN subtypes. Cox proportional hazards regression models were used to evaluate the association between diabetes and incidence of subtype-specific prostate cancer.

RESULTS

During 28 years of follow-up, we documented 6733 incident prostate cancer cases. Relative to men free from diabetes, men with diabetes had lower risks of total (HR: 0.82, 95% CI: 0.75-0.90), localised (HR: 0.82, 95% CI: 0.74-0.92), low-and intermediate-grade prostate cancer (HR: 0.77, 95% CI: 0.66-0.90; HR: 0.77, 95% CI: 0.65-0.91, respectively). For molecular subtypes, the HRs for ERG-negative and ERG-positive cases were 0.63 (0.42-0.95) and 0.72 (0.46-1.12); and for PTEN-intact and PTEN-loss cases were 0.69 (0.48-0.98) and 0.52 (0.19-1.41), respectively.

CONCLUSION

Besides providing advanced evidence for the inverse association between diabetes and prostate cancer, this study is the first to report associations between diabetes and ERG/PTEN defined prostate cancers.

TTBK2 circular RNA promotes glioma malignancy by regulating miR-217/HNF1β/Derlin-1 pathway

BACKGROUND

Circular RNAs are a subgroup of non-coding RNAs and generated by a mammalian genome. Herein, the expression and function of circular RNA circ-TTBK2 were investigated in human glioma cells.

METHODS

Fluorescence in situ hybridization and quantitative real-time PCR were conducted to profile the cell distribution and expression of circ-TTBK2 and microRNA-217 (miR-217) in glioma tissues and cells. Immunohistochemical and western blot were used to determine the expression of HNF1β and Derlin-1 in glioma tissues and cells. Stable knockdown of circ-TTBK2 or overexpression of miR-217 glioma cell lines (U87 and U251) were established to explore the function of circ-TTBK2 and miR-217 in glioma cells. Further, luciferase reports and RNA immunoprecipitation were used to investigate the correlation between circ-TTBK2 and miR-217. Cell Counting Kit-8, transwell assays, and flow cytometry were used to investigate circ-TTBK2 and miR-217 function including cell proliferation, migration and invasion, and apoptosis, respectively. ChIP assays were used to ascertain the correlations between HNF1β and Derlin-1.

RESULTS

We found that circ-TTBK2 was upregulated in glioma tissues and cell lines, while linear TTBK2 was not dysregulated in glioma tissues and cells. Enhanced expression of circ-TTBK2 promoted cell proliferation, migration, and invasion, while inhibited apoptosis. MiR-217 was downregulated in glioma tissues and cell lines. We also found that circ-TTBK2, but not linear TTBK2, acted as miR-217 sponge in a sequence-specific manner. In addition, upregulated circ-TTBK2 decreased miR-217 expression and there was a reciprocal negative feedback between them in an Argonaute2-dependent manner. Moreover, reintroduction of miR-217 significantly reversed circ-TTBK2-mediated promotion of glioma progression. HNF1β was a direct target of miR-217, and played oncogenic role in glioma cells. Remarkably, circ-TTBK2 knockdown combined with miR-217 overexpression led to tumor regression in vivo.

CONCLUSIONS

These results demonstrated a novel role circ-TTBK2 in the glioma progression.