The voltage gated Ca2+-channel Cav3.2 and therapeutic responses in breast cancer

Pera, Elena, Kaemmerer, Elke, Milevskiy, Michael J. G., Yapa, Kunsala T. D. S., O'Donnell, Jake S., Brown, Melissa A., Simpson, Fiona, Peters, Amelia A., Roberts-Thomson, Sarah J. and Monteith, Gregory R. (2016) The voltage gated Ca2+-channel Cav3.2 and therapeutic responses in breast cancer. Cancer Cell International, 16 24: . doi:10.1186/s12935-016-0299-0

Author Pera, Elena
Kaemmerer, Elke
Milevskiy, Michael J. G.
Yapa, Kunsala T. D. S.
O'Donnell, Jake S.
Brown, Melissa A.
Simpson, Fiona
Peters, Amelia A.
Roberts-Thomson, Sarah J.
Monteith, Gregory R.
Title The voltage gated Ca2+-channel Cav3.2 and therapeutic responses in breast cancer
Formatted title
The voltage gated Ca2+-channel Cav3.2 and therapeutic responses in breast cancer
Journal name Cancer Cell International   Check publisher's open access policy
ISSN 1475-2867
Publication date 2016-03-31
Sub-type Article (original research)
DOI 10.1186/s12935-016-0299-0
Open Access Status DOI
Volume 16
Issue 24
Total pages 15
Place of publication London, United Kingdom
Publisher BioMed Central
Collection year 2017
Language eng
Formatted abstract
Background:  Understanding the cause of therapeutic resistance and identifying new biomarkers in breast cancer to predict therapeutic responses will help optimise patient care. Calcium (Ca2+)-signalling is important in a variety of processes associated with tumour progression, including breast cancer cell migration and proliferation. Ca2+-signalling is also linked to the acquisition of multidrug resistance. This study aimed to assess the expression level of proteins involved in Ca2+-signalling in an in vitro model of trastuzumab-resistance and to assess the ability of identified targets to reverse resistance and/or act as potential biomarkers for prognosis or therapy outcome.

Methods:  Expression levels of a panel of Ca2+-pumps, channels and channel regulators were assessed using RT-qPCR in resistant and sensitive age-matched SKBR3 breast cancer cells, established through continuous culture in the absence or presence of trastuzumab. The role of Cav3.2 in the acquisition of trastuzumab-resistance was assessed through pharmacological inhibition and induced overexpression. Levels of Cav3.2 were assessed in a panel of non-malignant and malignant breast cell lines using RT-qPCR and in patient samples representing different molecular subtypes (PAM50 cohort). Patient survival was also assessed in samples stratified by Cav3.2 expression (METABRIC and KM-Plotter cohort).

Results:  Increased mRNA of Cav3.2 was a feature of both acquired and intrinsic trastuzumab-resistant SKBR3 cells. However, pharmacological inhibition of Cav3.2 did not restore trastuzumab-sensitivity nor did Cav3.2 overexpression induce the expression of markers associated with resistance, suggesting that Cav3.2 is not a driver of trastuzumab-resistance. Cav3.2 levels were significantly higher in luminal A, luminal B and HER2-enriched subtypes compared to the basal subtype. High levels of Cav3.2 were associated with poor outcome in patients with oestrogen receptor positive (ER+) breast cancers, whereas Cav3.2 levels were correlated positively with patient survival after chemotherapy in patients with HER2-positive breast cancers.

Conclusion:  Our study identified elevated levels of Cav3.2 in trastuzumab-resistant SKBR3 cell lines. Although not a regulator of trastuzumab-resistance in HER2-positive breast cancer cells, Cav3.2 may be a potential differential biomarker for survival and treatment response in specific breast cancer subtypes. These studies add to the complex and diverse role of Ca2+-signalling in breast cancer progression and treatment.
Keyword Biomarker
Breast cancer
Cav3.2 (CACNA1H)
Therapeutic response
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

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Created: Fri, 08 Apr 2016, 10:16:10 EST by Mrs Louise Nimwegen on behalf of School of Chemistry & Molecular Biosciences