Category Archives: Breast Cancer

Transient CB2R modulation durably restricts breast cancer plasticity by stabilizing a luminal like cell identity

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New breast cancer research suggests that brief modulation of cannabinoid receptor 2 (CB2R), including with THC, may have lasting effects on tumor cell behavior. Researchers found reduced self-renewal, invasiveness, and tumor-initiating capacity, along with greater tamoxifen sensitivity and a durable shift toward a more stable luminal-like cell identity.

“Cancer cell plasticity enables therapy resistance and metastasis by allowing transitions between stem-like and differentiated states. Differentiation-based strategies aim to stabilize tumor cell identity, yet pharmacological approaches that induce durable lineage restriction remain limited.

Here, we show that transient modulation of cannabinoid receptor 2 (CB2R) durably restricts breast cancer cell plasticity by stabilizing a luminal-like cell state. Using patient-derived and murine tumor organoids, we demonstrate that brief, low-dose CB2R modulation reduces self-renewal, invasiveness and tumor-initiating capacity, while enhancing tamoxifen sensitivity and limiting the emergence of resistant phenotypes.

These effects persist under pro-dedifferentiation conditions, including TGFβ exposure, stromal co-culture, immune signaling and mechanical stress, and are maintained in vivo following orthotopic transplantation. RNA sequencing reveals a progressive transition from an early plastic state toward a stabilized luminal-like identity, supported by CUT&Tag profiling that uncovers chromatin remodeling associated with this stabilization.

Together, our findings redefine CB2R as a regulator of tumor cell state and establish transient CB2R modulation as a strategy to durably constrain breast cancer plasticity through differentiation-based therapy.”

https://www.nature.com/articles/s42003-026-10837-1

“Low-dose THC keeps breast cancer cells in tumor models from reverting to an aggressive state”

https://medicalxpress.com/news/2026-09-dose-thc-breast-cancer-cells.html

Cannabidiolic acid causes a defect in tail retraction of migrating MDA-MB-231 cells: possible involvements of Rho-associated protein kinases inhibition and accumulation of vinculin at the rear of migrating cells

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A new study adds mechanistic detail to earlier evidence that cannabidiolic acid (CBDA) can interfere with the migration of highly aggressive MDA-MB-231 breast cancer cells. Researchers found that CBDA inhibited Rho-associated kinases (ROCKs), impaired tail retraction, altered cell shape and caused vinculin to accumulate at the trailing edge—revealing another way this cannabis-derived compound may disrupt cellular behavior involved in cancer spread.

“We previously reported that cannabidiolic acid (CBDA), a major cannabinoid constituent of the fiber-type cannabis plant, abrogates the migration of highly aggressive human breast cancer MDA-MB-231 cells and activates the small GTPase RhoA by inhibiting protein kinase A. However, the mechanism(s) mediating RhoA signaling, which decreases cell migration, have not yet been comprehensively elucidated.

RhoA is an upstream mediator of Rho-associated kinases (ROCKs), diaphanous-related formins (DIAPHs), the RhoA-ROCK pathway (tail retraction) and the RhoA-DIAPH pathway (lamellipodia formation).

Herein, we identified CBDA as an inhibitor of ROCKs (at approximately 25 μM), which markedly elongated the cell body of MDA-MB-231 cells, similar to Y-27632, an established ROCK inhibitor.

CBDA stimulated lamellipodia formation at the leading edge, whereas NSC23766 (an established Rac1 inhibitor) completely blocked this elongated morphology. Biochemical analyses, including time-lapse imaging and confocal laser scanning microscopy, revealed that, compared to Y-27632, CBDA can induce impaired tail retraction coupled with unidirectional elongation of the cell body, upregulate the mRNA expression of DIAPHs and accumulate vinculin, an adhesion protein, at the trailing edge without affecting its expression.

These results indicate the potential of CBDA as a new candidate for the synthesis of ROCK inhibitors, which can evoke the directed elongation of MDA-MB-231 cells.”

https://pubmed.ncbi.nlm.nih.gov/42186359

https://academic.oup.com/jb/article-abstract/180/2/143/8693860?redirectedFrom=fulltext

The role of cannabidiol treatment in reducing HER2 expression and inducing ER stress-mediated apoptosis in HER2-positive breast cancer

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Researchers examining cannabidiol (CBD) in HER2-positive breast cancer cells found that CBD significantly reduced HER2 gene expression while activating endoplasmic reticulum (ER) stress pathways, decreasing cell viability, and increasing apoptosis. The findings identify another potential molecular mechanism behind CBD’s previously observed anticancer activity in breast cancer and suggest that CBD warrants further investigation both alone and in combination with HER2-targeted therapy.

“Cannabidiol (CBD) has attracted attention as a potential anticancer agent due to its observed efficacy, particularly in breast cancer. However, the exact molecular pathway through which it exerts its anticancer effects remains unknown. The present study aimed to investigate the effects of CBD on the HER2 receptor, endoplasmic reticulum (ER) stress signaling pathway, and apoptosis in HER2-positive breast cancer cells, as well as to examine the effect of trastuzumab (TZB), used in treatment, on the ER stress signaling pathway.

Methods

For this purpose, SKBR3 cells were treated with CBD at three different concentrations (9.38, 18.75, and 37.5 µM), TZB at 62.5 µg/mL, and two combinations of TZB and CBD (18.75 µM CBD + 62.5 µg/mL TZB and 37.5 µM CBD + 62.5 µg/mL TZB). Cell proliferation was assessed using real-time cell analysis, while expression levels of ER stress-associated genes were measured by qPCR. Apoptosis was analyzed by Annexin V/PI flow cytometry.

Results

Findings revealed that CBD, TZB, or their combination were associated with reduced cell proliferation, significant activation of ER stress pathways, and increased apoptosis, while CBD was associated with marked downregulation of HER2 gene expression. Treatment with 9.38 µM CBD, 18.75 µM CBD, 37.5 µM CBD, 62.5 µg/mL TZB, 18.75 µM CBD + 62.5 µg/mL TZB, and 37.5 µM CBD + 62.5 µg/mL TZB significantly increased GRP78, PERK, IRE1, ATF6, eIF2A, ATF4, CHOP, and XBP1s gene expression levels, and significantly decreased HER2 gene expression at all doses except 62.5 µg/mL TZB. All doses significantly increased the total number of apoptotic cells and were associated with significantly reduced cell viability.

Conclusions

The present findings demonstrated that both TZB and CBD are associated with activation of the ER stress response and induction of apoptosis in HER2-positive breast cancer cells, and that CBD is associated with downregulation of HER2 receptor gene expression. Collectively, our results indicate that CBD may have potential as an adjunct or alternative strategy in HER2-positive breast cancer, although further in vivo studies are required to evaluate the efficacy and safety of its combination with low-dose TZB.”

https://link.springer.com/article/10.1186/s12906-026-05523-y

Preclinical antitumor evaluation of a tetrahydrocannabinol and cannabidiol (1:6) cannabis extract in an MCF-7 xenograft model of estrogen receptor-positive breast cancer

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Estrogen receptor-positive breast cancer remains one of the most common forms of breast cancer, and new adjunctive treatment strategies are still needed. In this mouse xenograft study, a whole-cannabis extract containing THC and CBD in a 1:6 ratio significantly suppressed tumor growth, reduced tumor-cell proliferation, and increased apoptosis-related changes, with the highest dose producing the greatest reduction in tumor volume. The researchers concluded that the extract showed promising antiproliferative and antitumor activity and may warrant further investigation as an adjunctive approach for ER-positive breast cancer.

“Background and aim: Breast cancer remains one of the leading causes of cancer-related mortality worldwide, despite advances in surgery, chemotherapy, endocrine therapy, and targeted treatments. Cannabinoids derived from Cannabis sativa, particularly tetrahydrocannabinol (THC) and cannabidiol (CBD), have demonstrated anticancer properties in several experimental models; however, in vivo evidence in estrogen receptor (ER)-positive breast cancer remains limited. This study aimed to evaluate the antitumor effects of a THC:CBD (1:6) cannabis extract in a Michigan Cancer Foundation-7 breast cancer cell line (MCF-7) xenograft mouse model of ER-positive breast cancer.

Materials and methods: Female BALB/c nude mice bearing MCF-7 xenograft tumors were randomly assigned into five groups (n = 5/group): negative control (sesame oil), positive control treated with 5-fluorouracil (5-FU; 20 mg/kg), and three treatment groups receiving oral THC:CBD (1:6) extract at doses of 2, 10, or 20 mg/kg body weight for 30 consecutive days. Tumor growth was monitored throughout the experiment. Histopathological examination and immunohistochemical analysis of proliferating cell nuclear antigen (PCNA) expression were performed to evaluate apoptosis-related morphology and tumor cell proliferation. Hematological and biochemical parameters were assessed to determine systemic safety.

Results: Cannabinoid-treated groups exhibited significant suppression of tumor growth compared with the negative control group. Tumor volume reduction was observed in all treatment groups, with the greatest reduction detected in the high-dose THC:CBD group. Histopathological evaluation revealed increased numbers of tumor cells exhibiting morphological features consistent with apoptosis in cannabinoid-treated mice. Immunohistochemical analysis demonstrated significantly lower PCNA expression scores in all THC:CBD-treated groups compared with both negative and positive controls, indicating reduced tumor cell proliferation. Hematological parameters remained within normal physiological ranges in cannabinoid-treated animals. However, elevated alanine aminotransferase and aspartate aminotransferase levels were observed in the high-dose group, suggesting potential dose-related hepatic stress.

Conclusion: The THC:CBD (1:6) cannabis extract demonstrated significant antitumor activity in an MCF-7 xenograft model by suppressing tumor progression primarily through inhibition of tumor cell proliferation, with supportive apoptosis-related histological features. These findings provide novel in vivo evidence supporting the potential of cannabinoid-based formulations as adjunctive therapeutic approaches for ER-positive breast cancer.”

https://pubmed.ncbi.nlm.nih.gov/42494695

“In conclusion, the present study demonstrated that the THC:CBD (1:6) whole-cannabis extract exerted significant antitumor activity in an MCF-7 xenograft model of ER-positive breast cancer. Treatment with the cannabinoid extract resulted in marked suppression of tumor growth, significant reduction in tumor volume, decreased PCNA expression, and increased numbers of tumor cells exhibiting apoptosis-related morphological features.

Among the tested doses, the high-dose THC:CBD group showed the greatest reduction in tumor volume, indicating a strong antiproliferative effect of the cannabinoid formulation.”

“Overall, despite the inherent limitations of xenograft models, the present findings indicate that the THC:CBD (1:6) cannabis extract possesses promising antiproliferative and antitumor properties in ER-positive breast cancer. These results provide a foundation for future mechanistic and translational studies exploring cannabinoids as potential adjunctive agents in breast cancer therapy.”

https://veterinaryworld.org/Vol.19/June-2026/17.php

Cannabis sativa phytochemicals in cancer therapy: molecular mechanisms and therapeutic potential

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Cannabis cancer research now extends far beyond THC and CBD alone. This 2026 review examines how cannabinoids, flavonoids, and other Cannabis sativa phytochemicals interact with molecular pathways involved in tumor growth, including apoptosis, oxidative stress, autophagy, angiogenesis, and metastasis. The authors highlight evidence involving THC, CBD, CBG, and several flavonoids across cancers including breast, bladder, melanoma, and pancreatic cancer, while also emphasizing that combinations are not always synergistic and that promising laboratory findings have not consistently translated into clinical success. The review concludes that cannabis-derived compounds remain important candidates for integrative oncology, but their potential will depend on better dosing strategies, rational combinations, targeted delivery, and rigorous clinical evaluation.

“Background: The therapeutic potential of Cannabis sativa has attracted growing interest in oncology. Its diverse phytochemicals, including cannabinoids, flavonoids, and terpenes, interact with oncogenic signaling pathways and the endocannabinoid system influencing tumour progression and therapeutic responses.

Objective: This review critically evaluates the molecular mechanisms by which Cannabis sativa phytochemicals modulate cancer pathways, with emphasis on apoptosis, oxidative stress regulation, autophagy, angiogenesis, and metastasis. It also explores synergistic and additive interactions among cannabinoids and flavonoids, highlighting their translational relevance.

Key findings: Cannabinoids such as Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabigerol (CBG) exhibit pathway-specific effects, including induction of apoptosis, modulation of oxidative stress, and inhibition of angiogenesis. Flavonoids such as cannflavin A, genistein, daidzein, hesperetin, and naringenin exhibit selective cytotoxicity across bladder, breast, melanoma, and pancreatic cancers, often sparing normal tissue. Importantly, phytochemical interactions are not uniformly synergistic; while combinations such as THC and CBD amplify apoptotic signaling, others act additively or antagonistically. Clinical formulations such as Nabiximols provide translational evidence of cannabinoid synergy, although outcomes remain context-dependent.

Conclusion: The disconnect between preclinical efficacy and clinical outcomes underscores critical gaps in dosing strategies, patient selection, and combination regimens. Future research should prioritize mechanistic studies, rational phytochemical combinations, and innovative drug delivery systems. Taken together, Cannabis sativa phytochemicals emerge as promising molecular entities with the potential to reshape integrative oncology, provided their therapeutic promise is matched with rigorous, evidence-based evaluation.”

https://pubmed.ncbi.nlm.nih.gov/42416829

“Taken together, these findings position Cannabis sativa phytochemicals not merely as natural products of interest, but as promising molecular entities with the potential to reshape integrative oncology.”

https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2026.1768210/full

Sedative and anesthetic-sparing effects of perioperative full-spectrum cannabis oil in female dogs undergoing unilateral mastectomy and ovariohysterectomy

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Cannabis-based products are increasingly being studied for their potential to reduce the amount of sedative and anesthetic medication needed during surgery. In this veterinary study, female dogs undergoing mastectomy and ovariohysterectomy received full-spectrum cannabis oil as part of their perioperative care. The researchers found evidence of sedative and anesthetic-sparing effects, suggesting that cannabis oil may influence how much conventional anesthesia is required while also contributing to perioperative pain management. The findings are preliminary and specific to a veterinary surgical setting, but they add to emerging research on cannabinoids as adjuncts to anesthesia and postoperative care.

“The anesthetic management of female dogs with mammary neoplasia, usually classified as ASA II and undergoing invasive procedures such as mastectomy and ovariohysterectomy, requires effective sedation and anesthetic stability due to the increased anesthetic risk associated with advanced age and underlying disease.

In this context, this study aimed to evaluate the sedative effects and reduction in anesthetic requirements of a full-spectrum cannabis oil (FSCO) containing cannabidiol (CBD) and tetrahydrocannabinol (THC) in female dogs undergoing mastectomy and ovariohysterectomy.

Twenty dogs were randomly assigned to two groups: group A (n = 10), treated with FSCO (0.02 mL/kg PO; 0.2 mg/kg CBD and 0.12 mg/kg THC) twice daily for seven days, plus 0.2 mL/kg (2 mg/kg CBD; 1.2 mg/kg THC) one hour before premedication; and group B (n = 10), treated with placebo. Groups A and B had similar ages (9.6; 10.2 years) and weights (7.4; 6.8 kg). Anesthesia was induced with propofol and maintained with sevoflurane. Outcomes included sedation scores, anesthetic requirements, rescue analgesia, responses to instrumentation, and adverse effects. The treated group required less propofol (2.33 vs. 5.98 mg/kg; p = 0.001) and lower sevoflurane concentrations from T0 to T4 (p < 0.05). Sedation scores were higher at 40 and 60 min (median of 4 vs. 0, and 6.5 vs. 0.5; p = 0.015 and p = 0.002, respectively). Fewer treated dogs required rescue analgesia (3/10 vs. 6/10; p = 0.178). No differences were observed in catheterization, intubation, or adverse effects.

Preoperative CBD/THC oil produced sedative effects and reduced anesthetic requirements without clinical complications.

These findings support the potential of cannabinoids as safe adjuvants in multimodal anesthesia in veterinary medicine.”

https://pubmed.ncbi.nlm.nih.gov/42348039

“The findings of this study indicate that preoperative administration of full-spectrum Cannabis sativa oil containing CBD and THC exerts significant sedative and anesthetic-sparing effects in female dogs with mammary neoplasia undergoing mastectomy and ovariohysterectomy.

The use of this phytocannabinoid extract significantly reduced the required doses of both propofol for induction and sevoflurane for maintenance, supporting its potential as an adjuvant in multimodal anesthetic protocols. Furthermore, the therapy was not associated with clinical adverse effects or compromised anesthetic safety, suggesting a favorable safety profile for perioperative use in oncological patients.”

https://link.springer.com/article/10.1007/s11259-026-11367-1

Antitumor Activity of Cannabinoids and Their Interaction with Chemotherapy: A Systematic Review and Meta-Analysis of Preclinical Evidence

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Cannabinoids are increasingly being studied for direct antitumor effects and for their ability to influence the response to conventional chemotherapy. This systematic review and meta-analysis of preclinical research found that cannabinoids significantly reduced tumor growth and cancer-cell viability across multiple models. The analysis also identified evidence that cannabinoids can enhance the effectiveness of several chemotherapy agents, supporting the possibility of useful combination strategies. The findings strengthen the case for cannabinoids as biologically active anticancer compounds with potential both as direct therapies and as adjuncts to standard treatment.

“Background: Cannabinoids are studied as anticancer agents, but their effects vary across tumors, compounds, and experimental settings, underscoring the need to define consistent patterns. Our objective was to map cannabinoid efficacy across cancer preclinical models and identify tumor settings with the greatest translational promise. 

Methods: The protocol was registered on PROSPERO (CRD42025543744); PubMed, Embase, and CENTRAL were searched on 4 April 2024 for in vitro and in vivo studies assessing cannabinoid antitumor effects alone or with chemotherapy versus vehicle or chemotherapy only. Random-effects models yielded pooled mean differences (MD) with 95% confidence intervals (CI). MDs of viable cells were calculated for in vitro assays and tumor volume (mm3) for in vivo studies. Reports of various compounds, cannabidiol (CBD), tetrahydrocannabinol (THC) or synthetic cannabinoids, were pooled. 

Results: We included 189 studies in the final analysis. In vitro, cannabinoids reduced cell viability modestly overall, with significant effects in glioblastoma (MD -18.77 [CI: -27.15; -10.39]) and a nonsignificant trend in breast cancer (MD -6.75 [CI: -13.90; 0.40]). For in vivo, monotherapy showed the most consistent efficacy in glioblastoma, significantly reducing tumor volume by MD -980.58 mm3; [CI: -1270.2; -690.88]. Addition to temozolomide produced a favorable but nonsignificant decrease of MD -220.65 mm3; [CI: -579.34; 138.03, vs. temozolomide]. In breast cancer, cannabinoids achieved smaller yet significant tumor reductions (MD -402.64 mm3); [CI: -671.84; -133.45]. Synthetic agents had the largest effect (MD -1295.19 mm3); [CI: -1664.33; -928.05] -CBD plus doxorubicin vs. doxorubicin). Lung cancer (MD -562.17 mm3); [CI: -693.99; -430.35] and prostate cancer (MD -1136.59 mm3); [95% CI: -1320.97; -952.21] also had a significant response, whereas colon, pancreatic, and hepatocellular carcinoma models showed inconsistent or null responses. 

Conclusions: Cannabinoids show promise as adjuncts in oncotherapy, particularly in glioblastoma and breast cancer, to enhance chemotherapy efficacy. These findings should be interpreted with caution given the high inter-study heterogeneity typical of preclinical research and should be considered hypothesis-generating, warranting further validation in standardized and clinically relevant models.”

https://pubmed.ncbi.nlm.nih.gov/42198443

“Cannabinoids have attracted growing attention in oncology as both supportive agents and potential direct antitumor therapies.”

“Beyond symptom management, preclinical studies over the past two decades have demonstrated that exogenous cannabinoids can influence key hallmarks of cancer, including proliferation, apoptosis, angiogenesis, and metastasis.”

“Notably, multiple studies indicate that cannabinoids can act synergistically with chemotherapy or radiotherapy, amplifying antitumor effects while potentially attenuating treatment-related toxicity. These interactions are clinically appealing, as they suggest a capacity to sensitize tumor cells to conventional agents and possibly enable dose reductions that limit systemic adverse effects.”

“Cannabinoids show emerging potential as adjuncts in oncological treatment, with relatively consistent signals observed particularly in glioblastoma and breast cancer models.”

https://www.mdpi.com/1424-8247/19/5/768

Computational Characterization of Nabilone-Induced Disruption of the CB2-HER2 Receptor Complex in HER2+ Breast Cancer

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HER2-positive breast cancer is driven in part by abnormal signaling through the HER2 receptor, making disruption of that pathway an important therapeutic target. In this computational study, researchers found that nabilone, a synthetic cannabinoid, may disrupt the CB2-HER2 receptor complex and alter interactions involved in HER2-driven cancer signaling. The findings suggest a potential molecular mechanism through which cannabinoid-based compounds could interfere with breast cancer progression. This work adds another layer to the growing evidence linking cannabinoid receptor signaling with direct effects on HER2-positive breast cancer biology.

“Human epidermal growth factor receptor 2-positive (HER2+) breast cancer, accounting for 15% to 20% of cases, is often resistant to treatment.

Delta-9-tetrahydrocannabinol (THC) disrupts HER2-cannabinoid receptor (2CB2) receptor complexes and inhibits HER2 activation.

This study evaluates whether Nabilone, a synthetic cannabinoid, can similarly disrupt HER2-CB2 interactions.

A CB2-HER2 complex model was generated via protein-protein docking. Three 1-µs molecular dynamics simulations (CB2-HER2, CB2-HER2-THC, CB2-HER2-Nabilone) were performed using the Schrodinger Desmond with membrane embedding and solvent. Structural stability (root mean square deviation [RMSD] and root mean square fluctuation [RMSF]), binding free energy (molecular mechanics/generalized born surface area [MM/GBSA]), and intracellular/extracellular distances between receptors were analyzed. Intermolecular interactions were assessed using the MAPIYA server.

Nabilone induced comparable structural instability to THC, with increased RMSD and RMSF. The MM/GBSA analysis showed Nabilone increased the binding free energy between CB2 and HER2, indicating stronger disruption. Intracellular and extracellular distances between CB2 and HER2 increased, especially intracellularly, with Nabilone. Intermolecular interaction analysis revealed that Nabilone decreased the number of contacts, particularly hydrophobic interactions, between CB2 and HER2.

Our in silico model predicts that Nabilone may disrupt the HER2-CB2 complex, suggesting a hypothesis that it could serve as a potential therapeutic agent. These computational findings warrant urgent experimental validation.”

https://pubmed.ncbi.nlm.nih.gov/42164472

“Cannabinoids have produced antitumor responses in preclinical models of cancer, including HER2+ BC, via binding and activating cannabinoid receptors, CB1 and CB2, both G-protein coupled receptors (GPCRs).”

“Nabilone, a synthetic analog of THC, was Food and Drug Administration (FDA)-approved in 1985 as a relief treatment for chemotherapy-related side effects, such as vomiting and nausea.”

“Our results indicate that Nabilone effectively disrupts the oncogenic CB2-HER2 complex, weakening the heterodimer interface through a mechanism of structural instability similar to THC but with superior binding affinity to CB2. While these findings rely on in silico predictions, limited by simulation timescales and simplified membrane models, they highlight a distinct opportunity for repurposing Nabilone from symptom management to active cancer therapy. We conclude that these data provide a robust theoretical framework that justifies urgent experimental validation in living systems to confirm the therapeutic potential of disrupting CB2-HER2 signaling.”

https://journals.sagepub.com/doi/10.1177/11779322261449332

Modulation of the endocannabinoid system reduces inflammatory signalling in canine mammary carcinoma cells

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The endocannabinoid system is increasingly being studied as a regulator of inflammation within cancer cells. In this study, modulating endocannabinoid signaling in canine mammary carcinoma cells reduced inflammatory signaling pathways associated with tumor progression. The findings suggest that cannabinoid-related mechanisms may help alter the inflammatory environment that supports cancer growth, adding to evidence that the endocannabinoid system itself may represent a therapeutic target in mammary tumors.

“Background: Canine mammary carcinoma (CMC) is characterised by a chronic inflammatory microenvironment resembling human breast cancer; however, the upstream regulatory mechanisms driving this phenotype remain unclear. The endocannabinoid system (ECS) has emerged as a potential modulator of inflammation and tumour biology. This study investigated the role of the ECS in CMC and evaluated the anti-inflammatory effects of cannabidiol (CBD).

Methods: Primary cell cultures were established from surgically excised CMC tissues, with matched normal mammary epithelium used as controls. Basal mRNA expression of ECS-related receptors (CB1, CB2, transient receptor potential vanilloid 1 [TRPV1], G-protein-coupled receptor 55 [GPR55] and peroxisome proliferator-activated receptor alpha [PPAR-α]) and inflammatory mediators (COX-1, COX-2, interleukin [IL]-4, IL-6, IL-33, IL-17A, tumour necrosis factor-alpha [TNF-α] and LCN2) was assessed by reverse transcription quantitative polymerase chain reaction. Cytokine secretion (IL-6, IL-8, TNF-α and IL-17A) was quantified by enzyme-linked immunosorbent assay. Cell viability assays were performed to determine the 24-h IC50 of CBD (32 µM), and sub-cytotoxic concentrations (3, 10 and 20 µM) were subsequently applied for 24 h.

Results: Canine mammary carcinoma-derived cells exhibited significant overexpression of ECS receptors (CB1, CB2, TRPV1, GPR55 and PPAR-α) compared to normal controls. These cells also showed increased secretion of pro-inflammatory cytokines, including IL-6, IL-8, TNF-α and IL-17A. Treatment with CBD at 10-20 µM significantly downregulated key inflammatory genes, particularly COX-2, IL-6 and TNF-α, and reduced corresponding cytokine release without compromising cell viability.

Conclusion: The ECS is upregulated in CMC and appears to contribute to the inflammatory tumour microenvironment. Cannabidiol effectively attenuates this inflammatory phenotype at sub-cytotoxic concentrations, supporting its potential as a therapeutic agent in CMC.”

https://pubmed.ncbi.nlm.nih.gov/42078490

“These findings may also have relevant implications for human health, as CMC shares key molecular and pathological features with human breast cancer. Therefore, the modulation of ECS-related pathways observed in this study may reflect conserved mechanisms that could be exploited for the development of novel anti-inflammatory and anti-tumour strategies in human oncology.”

https://bvajournals.onlinelibrary.wiley.com/doi/10.1002/vro2.70034

The Effect of Cannabidiol on Cancer-Pathway Genes in Doxorubicin-Sensitive and Resistant Breast Cancer Cells

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Cannabidiol is being investigated for its ability to influence cancer-related gene activity, including in tumors that have become resistant to chemotherapy. In this study, CBD altered the expression of multiple genes involved in breast cancer growth, survival, apoptosis, and drug resistance in both doxorubicin-sensitive and doxorubicin-resistant breast cancer cells. The findings suggest that CBD may affect molecular pathways tied to treatment response and could be especially relevant to overcoming mechanisms associated with chemotherapy resistance.

“Purpose: Cannabidiol (CBD) is a primary bioactive, non-intoxicating cannabinoid found in the cannabis plant. Studies have shown that CBD causes anticancer activity by inhibiting the expression of growth factors and inducing apoptosis, leading to cell cycle arrest. In this study, we aimed to determine how CBD influences the expression of genes that affect cancer pathways in doxorubicin-sensitive (MCF-7) and doxorubicin-resistant (MCF-7/Adr) breast cancer cells. 

Materials and Methods: IC50 concentrations of CBD in MCF-7 and MCF-7/Adr cell lines were determined by the MTT cell cytotoxicity assay. RNA isolation and subsequent cDNA synthesis were performed for qPCR experiments with the determined IC50 values. The effects of CBD on the cell cycle and apoptosis were studied using flow cytometry. IC50 values of CBD were determined in MCF-7 and MCF-7/Adr breast cancer cell lines at eight different concentrations and at three different incubation periods (24 h, 48 h, and 72 h) with different doses. RT-qPCR was used to investigate the molecular mechanisms underlying the expression of genes involved in cancer pathway analysis. 

Results: Treatment with CBD at concentrations of 17.57 μM (MCF-7) and 11.41 μM (MCF-7/Adr) for 48 h decreased colony formation, induced apoptosis, and inhibited cell invasion in both cell lines. In addition, we observed significant alterations of angiogenesis, apoptosis, cell cycle, cellular senescence, DNA damage and repair, epithelial-to-mesenchymal transition, hypoxia, metabolism, telomeres, and telomerase in both cell lines. 

Conclusions: Our research indicates that CBD could be an effective natural bioactive compound for breast cancer treatment, inhibiting tumor cell proliferation and inducing apoptosis.”

https://pubmed.ncbi.nlm.nih.gov/42075870

“The plant Cannabis sativa has been used medicinally for several thousand years.”

“These findings support the relevance of CBD as a potential therapeutic agent in breast cancer and provide a basis for further investigation “

https://www.mdpi.com/1424-8247/19/4/615