Adenylate cyclase 9 expression level is associated with hormone receptor-positive breast cancer and predicts patient prognosis

Abstract

Adenylate cyclase family members have recently received attention as novel therapeutic targets. However, the significance of adenylate cyclase 9 (ADCY9) in breast cancer has not been elucidated. Here, we evaluated ADCY9 expression in breast cancer (BC) cell lines, and polymerase chain reaction array analysis was performed to determine the correlations between ADCY9 expression levels and 84 tumor-associated genes. The association of ADCY9 messenger RNA (mRNA) expression levels in clinical breast cancer specimens with patients' clinicopathological factors and prognosis was evaluated. The database of cancer cell line showed that estrogen receptor-positive and progesterone receptor-positive cells expressed higher ADCY9 mRNA levels. ADCY9 expression showed positive correlations with several oncogenes, such as TGFB1, CDKN1A, and BAX in the polymerase chain reaction array analysis. We defined the ratio of ADCY9 mRNA expression levels in breast cancer and adjacent noncancerous tissues as the "C/N ratio". Among 149 patients with BC, estrogen receptor-positive and progesterone receptor-positive patients exhibited higher C/N ratios than estrogen receptor-negative and progesterone receptor-negative patients, respectively. Patients in the lowest C/N ratio quartile experienced shorter prognosis periods. The C/N ratio of ADCY9 was found as an independent prognostic factor for disease-free survival. Thus, ADCY9 expression is high in hormone receptor-positive breast cancer, and its low expression indicates a poor prognosis in patients with breast cancer.

Keywords: ADCY9; breast cancer; estrogen receptor; prognostic marker.

Fig. 1

ADCY9 mRNA expression levels in BC cell lines Fig. 1A:Analysis of ADCY9 mRNA expression. Bar graphs indicate relative ADCY9 mRNA levels, which were obtained from the ADCY9 value divided by GAPDH value. ADCY9 mRNA expression levels were heterogeneous among cell lines. The expression status of ER and HER2 was determined from previous studies.^, Fig. 1B:In the Cancer Cell Line Encyclopedia database, ER-positive and PgR-positive BC cell lines expressed higher ADCY9 mRNA levels, in comparison with the ER-negative and PgR-negative BC cell lines, respectively. No significant differences were observed between HER2-positive and HER2-negative BC cells. ADCY9: adenylate cyclase 9 BC: breast cancer ER: estrogen receptor HER2: human epidermal growth factor receptor 2 PgR: progesterone receptor mRNA: messenger RNA

Fig. 2

ADCY9 C/N ratio in breast cancer tissues Fig. 2A:Relationship between the ADCY9 C/N ratio and pathological factors. No significant differences were observed in relation to the T factor, lymph node metastasis, or stage. Fig. 2B:Relationship between the ADCY9 C/N ratio and the conventional biomarkers. ADCY9 C/N ratio in the ER-positive and PgR-positive BC groups were significantly higher than those in the ER-negative and PgR-negative groups, respectively. The HER2-positive group showed a lower ADCY9 C/N ratio than the HER2-negative group. The triple-negative group showed a lower ADCY9 C/N ratio than the non-triple-negative group. ADCY9: adenylate cyclase 9 C/N ratio: ratio of mRNA expression levels between cancerous and noncancerous tissues ER: estrogen receptor HER2: human epidermal growth factor receptor 2 PgR: progesterone receptor

Fig. 3

Relationship between the ADCY9 C/N ratio and prognosis Fig. 3A, B:In the cohort that evaluated our samples, the low ADCY9 group showed shorter disease-free survival (A) and overall survival (B) than the other patients. Fig. 3C:According to the Kaplan–Meier Plotter, patients in the lowest-quartile ADCY9 group exhibited shorter relapse-free survival than the high ADCY9 group. ADCY9: adenylate cyclase 9 C/N ratio: ratio of mRNA expression levels between cancerous and noncancerous tissues