Can Triptolide Boost Cisplatin's Fight Against Triple-Negative Breast Cancer?
"New research explores how combining triptolide with cisplatin could offer a more effective strategy against triple-negative breast cancer by targeting DNA repair mechanisms."
Breast cancer remains a significant health challenge for women worldwide, with incidence rates steadily increasing. Among the various subtypes, triple-negative breast cancer (TNBC) poses a unique challenge due to its lack of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor 2 (HER2) expression. This absence of common receptors means that targeted therapies are ineffective, leaving conventional chemotherapy as the primary treatment option.
Unfortunately, TNBC is notorious for developing resistance to chemotherapy, leading to poor clinical outcomes and aggressive tumor behavior. The urgent need for new strategies to overcome drug resistance and improve treatment efficacy has led researchers to explore novel therapeutic approaches.
One promising avenue involves the use of triptolide, a natural compound derived from the traditional Chinese medicine Tripterygium wilfordii. Triptolide has demonstrated anti-inflammatory and anti-tumor activities in various cancers. Researchers are now investigating its potential to enhance the effectiveness of existing chemotherapy drugs like cisplatin in treating TNBC.
TNBC’s Treatment Challenge
Triple-negative breast cancer (TNBC) accounts for around 15–20% of all breast cancers and is defined by the absence of estrogen, progesterone, and HER2 receptors. A 2021 report describes TNBC as associated with early recurrence, distant metastasis, therapeutic resistance, and poor prognosis. Triptolide is a biologically active terpenoid extracted from Tripterygium wilfordii, and a 2024 review discusses its potential antitumor activity.
How Triptolide Enhances Cisplatin's Effectiveness: Targeting DNA Repair
Cisplatin, a platinum-based drug, is a cornerstone of chemotherapy for many cancers, including TNBC. It works by creating DNA crosslinks within cancer cells, which, if not repaired, can lead to cell death. However, TNBC cells often develop resistance to cisplatin by efficiently repairing the DNA damage, limiting the drug's effectiveness.
- XRCC1 and PARP1: These proteins are essential for repairing single-strand breaks and base excision repair. By reducing their levels, triptolide hinders the cancer cells' ability to fix DNA damage.
- RAD51: While triptolide also slightly decreases RAD51 levels, which is involved in homologous recombination, the primary impact appears to be on BER and single-strand break repair.
- Sensitization to Cisplatin: By interfering with these repair mechanisms, triptolide makes TNBC cells more vulnerable to cisplatin's DNA-damaging effects.
DNA Repair and Triptolide
A review of dietary phytochemicals reports that triptolide sensitizes TNBC cells to cisplatin by interfering with XRCC1/PARP1-mediated base excision repair and DNA single-strand breaks. Another review describes triptolide-related effects reported across breast cancer subtypes, including basal and triple-negative types, such as increased caspase-3 activity and regulation of DNA repair or damage. A separate study on curcumin and gemcitabine notes that TNBC cells may be particularly vulnerable to redox-modulating combinations, citing prior studies of natural-compound combinations; it does not specifically establish this effect for triptolide and cisplatin.
Limits of XRCC1 as a Marker
Research on base excision repair in TNBC cautions against treating XRCC1 expression alone as a complete measure of DNA repair capacity. The study reports that changes in XRCC1 expression indicate changes in repair capacity, but basal DNA damage levels and protein localization are better indicators of repair defects. This limits how confidently XRCC1 expression by itself can be used to interpret repair-related responses to DNA-damaging agents.
Platinum Response and pCR
A systematic review and meta-analysis reported similar pathological complete response (pCR) rates for carboplatin and cisplatin in neoadjuvant treatment of TNBC: 0.470 (95% CI, 0.401–0.539) and 0.473 (95% CI, 0.379–0.568), respectively. A separate meta-analysis of five studies involving 1,264 patients found platinum-based neoadjuvant chemotherapy was associated with a higher pCR rate than platinum-free treatment: 50.9% versus 31.5% (OR 2.21, 95% CI 1.46–3.34; p=0.0002). In BRCA1-associated breast cancer, approximately 60% of patients treated with neoadjuvant cisplatin achieved pCR, while a sizable percentage did not. These findings describe different comparisons and populations, rather than a single estimate of cisplatin benefit.
Future Implications: A New Approach to TNBC Therapy?
The study's findings suggest that triptolide could be a valuable addition to the treatment arsenal against TNBC. By targeting DNA repair mechanisms, triptolide enhances the effectiveness of cisplatin, potentially overcoming drug resistance and improving patient outcomes. Further research and clinical trials are needed to fully explore the potential of this combination therapy and to determine the optimal dosage and administration strategies. However, these findings offer a promising new avenue for combating this aggressive form of breast cancer.
Delivery and Safety Challenges
A 2026 review examines efforts to improve triptolide’s efficacy and safety, including derivative design and drug-delivery systems. A 2024 study describes targeted delivery and precise toxin release as a promising but challenging strategy for TNBC, and reports an aptamer-functionalized triptolide conjugate designed with a pH-responsive linker. A related report says the acidic TNBC lysosomal environment cleaves the acetal bond to release active triptolide; in vitro, AS-TP had the lowest IC50 across a panel of breast cancer cell lines and minimal toxicity in normal MCF-10A cells. These findings are preclinical and do not establish clinical safety or benefit.