Protein kinase C iota promotes glycolysis via PI3K/AKT/mTOR signalling in high grade serous ovarian cancer

BACKGROUND

Epithelial ovarian cancer, especially high grade serous ovarian cancer (HGSOC) is by far, the most lethal gynecological malignancy with poor prognosis and high relapse rate. Despite of availability of several therapeutic interventions including poly-ADP ribose polymerase (PARP) inhibitors, HGSOC remains unmanageable and identification of early detection biomarkers and therapeutic targets for this lethal malady is highly warranted. Aberrant expression of protein kinase C iota (PKCί) is implicated in many cellular and physiological functions involved in tumorigenesis including cell proliferation and cell cycle deregulation.

METHODS AND RESULTS

Two high grade serous ovarian cancer cells SKOV3 and COV362 were employed in this study. PKCί was genetically knocked down or pharmacologically inhibited and several functional and biochemical assays were performed. We report that PKCί is overexpressed in HGSOC cells and patient tissue samples with a significant prognostic value. Pharmacological inhibition of PKCί by Na-aurothiomalate or its shRNA-mediated genetic knockdown suppressed HGSOC cell proliferation, EMT and induced apoptosis. Moreover, PKCί positively regulated GLUT1 and several other glycolytic genes including HK1, HK2, PGK1, ENO1 and LDHA to promote elevated glucose uptake and glycolysis in HGSOC cells. Mechanistically, PKCί drove glycolysis via PI3K/AKT/mTOR signalling. Na-aurothiomalate and highly selective, dual PI3K/mTOR inhibitor dactolisib could serve as novel anti-glycolytic drugs in HGSOC.

CONCLUSION

Taken together, our results indicate PKCί/PI3K/AKT/mTOR signalling cascade could be a novel therapeutic target in a lethal pathology like HGSOC.

Clinicopathologic Characterization of Prostatic Cancer in Dogs

Clinicopathologic data in dogs with prostate cancer (PCa) may aid in the differentiation between tumor types and subsequent treatment decisions; however, these data are often unreported. Demographic, clinicopathologic, cytologic, histologic and survival data from dogs with primary prostatic adenocarcinoma (PRAD) (n = 56) and primary prostatic transitional cell carcinoma (P-TCC) (n = 74) were acquired from a tertiary veterinary teaching hospital from 1992 to 2022. Red blood cell distribution width (RDW) to albumin ratio (RAR) was evaluated for diagnostic utility in differentiating between PRAD and P-TCC. Sections from PRAD tumors (n = 50) were stained for androgen receptor (AR) expression, and laboratory data were compared between AR positive (AR+) and AR negative (AR-) groups. RDW was increased in PRAD, while albumin was decreased (p < 0.05). P-TCC was associated with Melamed-Wolinska bodies (MWB) and necrosis on cytology (p < 0.05). RAR had acceptable diagnostic utility in the differentiation of PCa tumors (AUC = 0.7; p < 0.05). Survival rates and metastases were equivocal. AR+ and AR- PRAD tumors did not differ in clinicopathologic data or survival (p > 0.05). In conclusion, hypoalbuminemia was significantly associated with PRAD and decreased survival, while MWB and necrosis were significantly associated with P-TCC on cytology. These clinicopathologic data may help clinicians differentiate between these tumors ante mortem to guide appropriate treatment and intervention.

An androgen receptor regulated gene score is associated with epithelial to mesenchymal transition features in triple negative breast cancers

BACKGROUND

Androgen receptor (AR) is considered a marker of better prognosis in hormone receptor positive breast cancers (BC), however, its role in triple negative breast cancer (TNBC) is controversial. This may be attributed to intrinsic molecular differences or scoring methods for AR positivity. We derived AR regulated gene score and examined its utility in BC subtypes.

METHODS

AR regulated genes were derived by applying a bioinformatic pipeline on publicly available microarray data sets of AR+ BC cell lines and gene score was calculated as average expression of six AR regulated genes. Tumors were divided into AR high and low based on gene score and associations with clinical parameters, circulating androgens, survival and epithelial to mesenchymal transition (EMT) markers were examined, further evaluated in invitro models and public datasets.

RESULTS

53% (133/249) tumors were classified as AR gene score high and were associated with significantly better clinical parameters, disease-free survival (86.13 vs 72.69 months, log rank p = 0.032) when compared to AR low tumors. 36% of TNBC (N = 66) were AR gene score high with higher expression of EMT markers (p = 0.024) and had high intratumoral levels of 5α-reductase, enzyme involved in intracrine androgen metabolism. In MDA-MB-453 treated with dihydrotestosterone, SLUG expression increased, E-cadherin decreased with increase in migration and these changes were reversed with bicalutamide. Similar results were obtained in public datasets.

CONCLUSION

Deciphering the role of AR in BC is difficult based on AR protein levels alone. Our results support the context dependent function of AR in driving better prognosis in ER positive tumors and EMT features in TNBC tumors.

Androgen Receptor Status in Triple Negative Breast Cancer: Does It Correlate with Clinicopathological Characteristics?

Purpose

Triple negative breast cancer (TNBC) is a breast carcinoma subtype that neither expresses estrogen (ER) and progesterone receptors (PR) nor the human epidermal growth factor receptor 2 (HER2). Patients with TNBC have been shown to have poorer outcomes mainly owing to the limited treatment options available. However, some studies have shown TNBC tumors expressing androgen receptors (AR), raising hopes of its prognostic role.

Patients and Methods

This retrospective study investigated the expression of AR in TNBC and its relationship with known patient demographics, tumor and survival characteristics. From the records of 205 TNBC patients, 36 had available archived tissue samples eligible for AR staining. For statistical purposes, tumors were classified as either "positive" or "negative" for AR expression. The nuclear expression of AR was scored by measuring the percentage of stained tumor cells and its staining intensity.

Results

AR was expressed by 50% of the tissue samples in our TNBC cohort. The relationship between AR status with age at the time of TNBC diagnosis was statistically significant, with all AR positive TNBC patients being greater than 50 years old (vs 72.2% in AR negative TNBC). Also, the relationship between AR status and type of surgery received was statistically significant. There were no statistically significant associations between AR status with other tumor characteristics including "TNM status", tumor grade or treatments received. There was no statistically significant difference in median survival between AR negative and AR positive TNBC patients (3.5 vs 3.1 years; p = 0.581). The relationship between OS time and AR status (p = 0.581), type of surgery (p = 0.061) and treatments (p = 0.917) were not statistically significant.

Conclusion

The androgen receptor may be an important prognostic marker in TNBC, with further research warranted. This research may benefit future studies investigating receptor-targeted therapies in TNBC.

Adjuvant enzalutamide for the treatment of early-stage androgen-receptor positive, triple-negative breast cancer: a feasibility study

PURPOSE

Chemotherapy with or without immunotherapy remains the mainstay of treatment for triple-negative breast cancer (TNBC). A subset of TNBCs express the androgen receptor (AR), representing a potential new therapeutic target. This study assessed the feasibility of adjuvant enzalutamide, an AR antagonist, in early-stage, AR-positive (AR +) TNBC.

METHODS

This study was a single-arm, open-label, multicenter trial in which patients with stage I-III, AR ≥ 1% TNBC who had completed standard-of-care therapy were treated with enzalutamide 160 mg/day orally for 1 year. The primary objective of this study was to evaluate the feasibility of 1 year of adjuvant enzalutamide, defined as the treatment discontinuation rate of enzalutamide due to toxicity, withdrawal of consent, or other events related to tolerability. Secondary endpoints included disease-free survival (DFS), overall survival (OS), safety, and genomic features of recurrent tumors.

RESULTS

Fifty patients were enrolled in this study. Thirty-five patients completed 1 year of therapy, thereby meeting the prespecified trial endpoint for feasibility. Thirty-two patients elected to continue with an optional second year of treatment. Grade ≥ 3 treatment-related adverse events were uncommon. The 1-year, 2-year, and 3-year DFS were 94%, 92% , and 80%, respectively. Median OS has not been reached.

CONCLUSION

This clinical trial demonstrates that adjuvant enzalutamide is a feasible and well-tolerated regimen in patients with an early-stage AR + TNBC. Randomized trials in the metastatic setting may inform patient selection through biomarker development; longer follow-up is needed to determine the effect of anti-androgens on DFS and OS in this patient population.

Molecular Characterization and Prospective Evaluation of Pathologic Response and Outcomes with Neoadjuvant Therapy in Metaplastic Triple-Negative Breast Cancer

PURPOSE

Metaplastic breast cancer (MpBC) is a rare subtype of breast cancer that is commonly triple-negative and poorly responsive to neoadjuvant therapy in retrospective studies.

EXPERIMENTAL DESIGN

To better define clinical outcomes and correlates of response, we analyzed the rate of pathologic complete response (pCR) to neoadjuvant therapy, survival outcomes, and genomic and transcriptomic profiles of the pretreatment tumors in a prospective clinical trial (NCT02276443). A total of 211 patients with triple-negative breast cancer (TNBC), including 39 with MpBC, received doxorubicin-cyclophosphamide-based neoadjuvant therapy.

RESULTS

Although not meeting the threshold for statistical significance, patients with MpBCs were less likely to experience a pCR (23% vs. 40%; P = 0.07), had shorter event-free survival (29.4 vs. 32.2 months, P = 0.15), metastasis-free survival (30.3 vs. 32.4 months, P = 0.22); and overall survival (32.6 vs. 34.3 months, P = 0.21). This heterogeneity is mirrored in the molecular profiling. Mutations in PI3KCA (23% vs. 9%, P = 0.07) and its pathway (41% vs. 18%, P = 0.02) were frequently observed and enriched in MpBCs. The gene expression profiles of each histologically defined subtype were distinguishable and characterized by distinctive gene signatures. Among nonmetaplastic (non-Mp) TNBCs, 10% possessed a metaplastic-like gene expression signature and had pCR rates and survival outcomes similar to MpBC.

CONCLUSIONS

Further investigations will determine if metaplastic-like tumors should be treated more similarly to MpBC in the clinic. The 23% pCR rate in this study suggests that patients with MpBC should be considered for NAT. To improve this rate, a pathway analysis predicted enrichment of histone deacetylase (HDAC) and RTK/MAPK pathways in MpBC, which may serve as new targetable vulnerabilities.

Immune Phenotype and Response to Neoadjuvant Therapy in Triple-Negative Breast Cancer

PURPOSE

Increasing tumor-infiltrating lymphocytes (TIL) is associated with higher rates of pathologic complete response (pCR) to neoadjuvant therapy (NAT) in patients with triple-negative breast cancer (TNBC). However, the presence of TILs does not consistently predict pCR, therefore, the current study was undertaken to more fully characterize the immune cell response and its association with pCR.

EXPERIMENTAL DESIGN

We obtained pretreatment core-needle biopsies from 105 patients with stage I-III TNBC enrolled in ARTEMIS (NCT02276443) who received NAT from Oct 22, 2015 through July 24, 2018. The tumor-immune microenvironment was comprehensively profiled by performing T-cell receptor (TCR) sequencing, programmed death-ligand 1 (PD-L1) IHC, multiplex immunofluorescence, and RNA sequencing on pretreatment tumor samples. The primary endpoint was pathologic response to NAT.

RESULTS

The pCR rate was 40% (42/105). Higher TCR clonality (median = 0.2 vs. 0.1, P = 0.03), PD-L1 positivity (OR: 2.91, P = 0.020), higher CD3⁺:CD68⁺ ratio (median = 14.70 vs. 8.20, P = 0.0128), and closer spatial proximity of T cells to tumor cells (median = 19.26 vs. 21.94 μm, P = 0.0169) were associated with pCR. In a multivariable model, closer spatial proximity of T cells to tumor cells and PD-L1 expression enhanced prediction of pCR when considered in conjunction with clinical stage.

CONCLUSIONS

In patients receiving NAT for TNBC, deep immune profiling through detailed phenotypic characterization and spatial analysis can improve prediction of pCR in patients receiving NAT for TNBC when considered with traditional clinical parameters.

Androgen receptor expression in breast cancer: Implications on prognosis and treatment, a brief review

Approximately 70%-85% of breast cancers express androgen receptors (ARs). The role of AR in breast cancer pathogenesis is currently in exploration. Both androgens and anti-androgens have demonstrated variable inhibitory and stimulatory effects in AR-positive breast cancer depending on estrogen receptor and HER2 co-expression. Androgen signaling pathways interact with other critical cellular pathways, such as the PI3K/AKT/mTOR, Ras/Raf/MAPK/ERK, Wnt/β-catenin, and estrogen signaling pathways. Therapeutic exploitation of AR has been the crux of management of prostate cancer for decades. In recent years there has been increasing interest in AR as a novel therapeutic target in breast cancer. There have been many early phase clinical trials evaluating the safety and efficacy of various AR-targeted agents in breast cancer. Some of these studies have shown promising clinical benefits. Studies of biomarkers to identify the patients likely to benefit from AR-targeted therapies are currently in progress. Besides, AR expression may be an important prognostic and predictive marker for breast cancer, which needs to be defined better in future studies.

[Androgen receptor-positive triple negative breast cancer: From biology to therapy]

A subgroup of androgen receptor-expressing tumors represents approximately 30 % of all triple negative tumors. The androgen receptor and its signaling pathways have a central biological role in this tumor entity. These triple negative androgen receptor-positive tumors occur in older patients and do not appear to have a better prognosis compared to other triple negative tumors. In addition to androgen receptor-expression, these tumors are genomically characterized by a high frequency of PIK3CA activating mutation. Three clinical trials reported efficacy data for anti-androgens (bicalutamide, abiraterone acetate and enzalutamide) based on strong preclinical rationale. These trials report clinical benefit rates in about one in five patients. These encouraging but still limited results make a case for the identification of predictive response factors and therapeutic combinations to improve response rates. This review will provide an update on the biological and clinical knowledge of this tumoral subgroup that opens the way to non-cytotoxic anti-androgen therapies.

Determination of the androgen receptor status of circulating tumour cells in metastatic breast cancer patients

BACKGROUND

The prognostic relevance of circulating tumour cells (CTCs) in metastatic breast cancer (MBC) patients has been confirmed by several clinical trials. However, predictive blood-based biomarkers for stratification of patients for targeted therapy are still lacking. The DETECT studies explore the utility of CTC phenotype for treatment decisions in patients with HER2 negative MBC. Associated with this concept is a plethora of translational projects aiming to identify potential predictive biomarkers. The androgen receptor (AR) is expressed in over 70% of hormone receptor-positive and up-to 45% of triple-negative tumours. Studies has indicated the promising nature of AR as a new therapy target with a clinical benefit rate for anti-AR treatment in MBC patients up to 25% The aim of this analysis was the characterization of CTCs regarding the expression of the AR using immunofluorescence.

METHODS

MBC patients were screened for the HER2-status of CTCs in the DETECT studies. In a subset of CTC-positive patients (n = 67) an additional blood sample was used for immunomagnetic enrichment of CTCs using the CellSearch® Profile Kit prior to transfer of the cells onto cytospin slides. Establishment of immunofluorescence staining for the AR was performed using prostate cancer cell lines LNCaP and DU145 as positive and negative control, respectively. Staining of DAPI, pan-cytokeratin (CK) and CD45 was applied to identify nucleated epithelial cells as CTCs and to exclude leucocytes.

RESULTS

Co-staining of the AR, CK and CD45 according to the above mentioned workflow has been successfully established using cell lines with known AR expression spiked into the blood samples from healthy donors. For this translational project, samples were analysed from 67 patients participating in the DETECT studies. At least one CTC was detected in 37 out of 67 patients (56%). In 16 of these 37 patients (43%) AR-positive CTCs were detected. In eight out of 25 patients (32%) with more than one CTC, AR-positive and AR-negative CTCs were observed.

CONCLUSION

In 43% of the analysed CTC samples from patients with MBC the AR expression has been detected. The predictive value of AR expression in CTCs remains to be evaluated in further trials.

Consideration of breast cancer subtype in targeting the androgen receptor

The androgen receptor (AR) is a drug target in breast cancer, and AR-targeted therapies have induced tumor responses in breast cancer patients. In this review, we summarized the role of AR in breast cancer based on preclinical and clinical data. Response to AR-targeted therapies in unselected breast cancer populations is relatively low. Preclinical and clinical data show that AR antagonists might have a role in estrogen receptor (ER)-negative/AR-positive tumors. The prognostic value of AR for patients remains uncertain due to the use of various antibodies and cut-off values for immunohistochemical assessment. To get more insight into the role of AR in breast cancer, we additionally performed a retrospective pooled analysis to determine the prognostic value of the AR using mRNA profiles of 7270 primary breast tumors. Our analysis shows that a higher AR mRNA level is associated with improved disease outcome in patients with ER-positive/human epidermal growth factor receptor 2 (HER2)-negative tumors, but with worse disease outcome in HER2-positive subgroups. In conclusion, next to AR expression, incorporation of additional tumor characteristics will potentially make AR targeting a more valuable therapeutic strategy in breast cancer.