Inhibition of smoothened in breast cancer cells reduces CAXII expression and cell migration

Abstract

Breast cancer (BC) relapse and metastasis are the leading cause of death and, together with drug resistance, keep mortality still high. The Hedgehog (Hh) pathway is expressed during embryogenesis, organogenesis and in adult tissue homeostasis and its aberrant activation is often associated with cancer. Carbonic anhydrase (CA) enzymes are important during development; they play a key role in controlling several cellular mechanisms, such as pH regulation, survival, and migration, and they are aberrantly expressed in cancer. The goal of this study was to investigate the interplay between the Hh pathway and CAXII in terms of BC cell migration. We here demonstrated that smoothened (SMO) silencing resulted in a reduction of CAXII expression at mRNA and protein level. This led to a decrease in cell migration, which was restored when cells were treated with an SMO agonist, Sag dihydrochloride (SAG), but not when cells were cotreated with SAG and the CAs inhibitor Acetazolamide. This suggested that the ability of SAG to promote cell migration was impaired when CAXII was inhibited. The reduction was also confirmed within hypoxic and inflammatory microenvironment, typical of BC, indicating a key role of the Hh pathway in controlling CAXII expression. Our results may contribute to further understand the physiology of BC cells and indicate that the Hh pathway controls BC cell migration and cell invasion also through CAXII, with important implications in identifying novel therapeutic targets.

Inhibition of Melanoma Cell Migration and Invasion Targeting the Hypoxic Tumor Associated CAXII

“…Recently, our research group discovered a correlation between the Hh pathway and CAXII on breast cancer cell migration [ 36 ]. The Hh pathway was already explored in melanoma [ 49 , 50 ], however its involvement in CAs modulation has not been investigated yet.…”

“…CAXII has been recently proposed as a possible target for anticancer therapy [ 31 ] and novel and specific inhibitors of this enzyme, along with CAIX, have been recently identified [ 33 ]. Furthermore, we have recently reported that CAXII expression is regulated by the Hh pathway in breast cancer, indicating that this enzyme plays a potential role in breast cancer cell migration and invasiveness [ 36 ]. We here report, for the first time, that the Hh pathway is involved in the modulation of CAXII also in melanoma cells, in particular, in a moderate aggressive melanoma cell line and, more interestingly, in hypoxic conditions.…”

“…It should be pointed out that in our experimental protocol C-10 was even more effective than the pan-inhibitors GV2-20 and AAZ. We and others have previously reported that CAXII promotes not only the migration but also invasive capability of breast cancer cells [ 36 , 64 ]. Indeed, the decreased invasiveness and migration ability of CAXII-knockdown cells were restored by an overexpression of CAXII [ 64 ].…”

“…While C-7 is a selective inhibitor only for CAIX, C-10 has the most potent effect not only on CAIX but also on CAXII [ 32 ]. We have recently shown that CAXII is regulated by the Hedgehog (Hh) pathway in breast cancer [ 35 , 36 ]. Physiologically, the Hh pathway controls organ development during embryogenesis, whereas in adults remains quiescent, except for tissue repairing [ 37 , 38 ].…”

Sonic Hedgehog Signaling in Organogenesis, Tumors, and Tumor Microenvironments

“…Guerrini et al found that the SHH signaling pathway regulates breast cancer cell migration and invasion through carbonic anhydrase (CA) II [126]. SHH pathway activation affects breast cancer metastasis [127].…”