Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2010 Jul 22:9:196.
doi: 10.1186/1476-4598-9-196.

Cannabinoids reduce ErbB2-driven breast cancer progression through Akt inhibition

Affiliations

Cannabinoids reduce ErbB2-driven breast cancer progression through Akt inhibition

María M Caffarel et al. Mol Cancer. .

Abstract

Background: ErbB2-positive breast cancer is characterized by highly aggressive phenotypes and reduced responsiveness to standard therapies. Although specific ErbB2-targeted therapies have been designed, only a small percentage of patients respond to these treatments and most of them eventually relapse. The existence of this population of particularly aggressive and non-responding or relapsing patients urges the search for novel therapies. The purpose of this study was to determine whether cannabinoids might constitute a new therapeutic tool for the treatment of ErbB2-positive breast tumors. We analyzed their antitumor potential in a well established and clinically relevant model of ErbB2-driven metastatic breast cancer: the MMTV-neu mouse. We also analyzed the expression of cannabinoid targets in a series of 87 human breast tumors.

Results: Our results show that both Delta9-tetrahydrocannabinol, the most abundant and potent cannabinoid in marijuana, and JWH-133, a non-psychotropic CB2 receptor-selective agonist, reduce tumor growth, tumor number, and the amount/severity of lung metastases in MMTV-neu mice. Histological analyses of the tumors revealed that cannabinoids inhibit cancer cell proliferation, induce cancer cell apoptosis, and impair tumor angiogenesis. Cannabinoid antitumoral action relies, at least partially, on the inhibition of the pro-tumorigenic Akt pathway. We also found that 91% of ErbB2-positive tumors express the non-psychotropic cannabinoid receptor CB2.

Conclusions: Taken together, these results provide a strong preclinical evidence for the use of cannabinoid-based therapies for the management of ErbB2-positive breast cancer.

PubMed Disclaimer

Figures

Figure 1
Figure 1
ErbB2-positive human breast tumors express cannabinoid receptors. (A) Representative images of human breast tumors negative (upper row) or positive (lower row) for CB1, CB2 and ErbB2 receptors (brown). Scale bars: 200 μm; insets: 100 μm. (B) Percentage of tumors scored as positive or negative for cannabinoid receptor expression amongst the ErbB2-negative (n = 64) and ErbB2-positive (n = 23) populations.
Figure 2
Figure 2
Cannabinoids inhibit breast tumor growth in vivo and the number of tumors generated per animal. (A) Volume time-course (scale bar: 1 cm) of the first tumor appeared in each animal. (B) Representative images (H&E staining) of the histopathology of the MMTV-neu-derived mammary tumors. Scale bars (from left to right): 200 μm, 100 μm and 50 μm. (C) Percentage of animals with 1, 2, 3, 4 or more tumors at the end of the treatment (90 days) in each experimental group. (D) Total tumor burden (total tumor volume per animal) determined 90 days after cannabinoid or vehicle treatment. (E) Volume of the tumors appeared in second, third or subsequent positions, 40 days after their appearance. The small size of the cannabinoid-treated groups is due to the very few second or third tumors appeared early enough to last 40 days in the animals before the end of the treatment (90 days after the appearance of the first tumor).
Figure 3
Figure 3
Cannabinoids inhibit cancer cell proliferation, induce cancer cell apoptosis, and impair tumor angiogenesis in vivo. (A) Ki67-positive cells (red), (B) active caspase-3-positive cells (red), (C) CD31-positive cells (green) and (D) CD45-positive area in the tumors. Scale bars: A, 60 μm; B, 40 μm; C and D, 100 μm. Cell nuclei are in blue. Quantifications of Ki67-positive cells (A), active caspase-3-positive cells (B), the number of blood vessels (C) and CD45-positive area (D) in the tumors are shown in the corresponding graphs.
Figure 4
Figure 4
Cannabinoids inhibit breast cancer metastasis to the lungs in vivo. (A) Metastatic lung nodules (pointed by arrows). (B) Percentage of animals with lung metastases. Macroscopic metastases were visible to the naked eye and microscopic lesions were detectable only by H&E staining. These latter lesions were found only in JWH-133-treated animals. (C) Gelatin zymographies of vehicle- and cannabinoid-treated tumors. Four representative tumors are shown per experimental group. PC: positive control (conditioned medium of H71080 cells stimulated with the phorbol ester PMA). Arrows point to the latent (pro-MMP) and active MMP bands according to the positive control and the expected MMP molecular weights. Non-contiguous parts of the same gel are shown. Graphs show the densitometric analysis of MMP2 and MMP9 activities. Data are expressed in arbitrary units. *, p < 0.05 vs vehicle-treated tumors; §, p = 0.068 vs vehicle-treated tumors.
Figure 5
Figure 5
THC inhibits Akt in vivo. (A) Mouse ErbB2 and (B) rat ErbB2 (neu transgene) mRNA expression in vehicle- and cannabinoid-treated tumors as determined by real-time quatitative PCR. (B and C) Western blot and densitometric analysis of phospho-Akt (B) and phospho-S6 ribosomal protein (C) levels in MMTV-neu-derived tumors treated with vehicle or THC. Eight representative tumors are shown. Total Akt (B) and α-tubulin (C) were used for normalization. Non-contiguous parts of the same gel are shown. Optical densities are expressed in arbitrary units.
Figure 6
Figure 6
Akt downregulation is involved in cannabinoid antitumoral action. (A and B) Viability of N202.1A cells in response to (A) increasing concentrations of THC or JWH-133 or (B) 6 μM THC or 10 μM JWH-133 with or without 2 μM SR141716 (SR1) and/or SR144528 (SR2) for 48 h. Data are expressed as % of vehicle-treated cells, set at 100%. (C) Growth of N202.1A-derived xenografts treated with THC (left panel) or JWH-133 (right panel) with or without SR2. (D) Phospho-Akt and phospho-S6 ribosomal protein (p-S6) levels in N202.1A cells challenged with THC, as determined by Western blot. Total Akt and α-tubulin levels were used for normalization. (E) Phospho-Akt and total Akt levels in N202.1A cells retrovirally transduced with myristoylated Akt (pBABE-Myr-Akt) or the corresponding empty vector (pBABE). (F) Cell viability of pBABE- or myr-Akt-transduced N202.1A cells in response to THC exposure for 72 h. (G and H) Time course of the volume of pBABE-N202.1A-derived (left panels) and myr-Akt-N202.1A-derived (right panels) tumors treated with THC (G), JWH-133 (H) or the corresponding vehicle. *, p < 0.05; **, p < 0.01 vs vehicle-treated cells or tumors; #, p < 0.05; ##, p < 0.01 vs cannabinoid alone-treated cells (B) or vs THC-treated pBABE-transduced cells (F).

Similar articles

Cited by

References

    1. Baselga J, Swain SM. Novel anticancer targets: revisiting ERBB2 and discovering ERBB3. Nat Rev Cancer. 2009;9:463–475. doi: 10.1038/nrc2656. - DOI - PubMed
    1. Ursini-Siegel J, Schade B, Cardiff RD, Muller WJ. Insights from transgenic mouse models of ERBB2-induced breast cancer. Nat Rev Cancer. 2007;7:389–397. doi: 10.1038/nrc2127. - DOI - PubMed
    1. Di Cosimo S, Baselga J. Targeted therapies in breast cancer: where are we now? Eur J Cancer. 2008;44:2781–2790. doi: 10.1016/j.ejca.2008.09.026. - DOI - PubMed
    1. Hynes NE, Lane HA. ERBB receptors and cancer: the complexity of targeted inhibitors. Nat Rev Cancer. 2005;5:341–354. doi: 10.1038/nrc1609. - DOI - PubMed
    1. Di Marzo V. Targeting the endocannabinoid system: to enhance or reduce? Nat Rev Drug Discov. 2008;7:438–455. doi: 10.1038/nrd2553. - DOI - PubMed

Publication types

MeSH terms