The DNA damage response in advanced ovarian cancer: functional analysis combined with machine learning identifies signatures that correlate with chemotherapy sensitivity and patient outcome

Olaparib increases chemosensitivity by upregulating miR-125a-3p in ovarian cancer cells

OBJECTIVE

Ovarian cancer is associated with the highest mortality rate among all malignant gynecological tumors. PolyADP-ribose polymerase (PARP) inhibitor maintenance therapy is the standard treatment strategy for this type of cancer, and olaparib is a widely used oral PARP inhibitor for tumors with BRCA mutations. The present study aimed to investigate the effects of olaparib in non-BRCA-mutated ovarian cancer and the potential mechanisms involved.

METHODS

The antitumor effect of cisplatin alone or in combination with olaparib was analyzed in an ovarian cancer subcutaneous transplantation tumor model in nude mice. Furthermore, the differences in microRNA (miRNA) expression levels were analyzed using miRNA arrays. In addition, the effects of miR-125a-3p on the proliferation of non-BRCA-mutated (A2780 and OVCAR-3) ovarian cancer cells were detected using A Cell Counting Kit-8 and changes in the cell cycle were detected using flow cytometry. Furthermore, SPiDER-βGal was used to detect expression changes in cellular senescence, and the expression of DNA damage repair proteins was detected using western blot analysis.

RESULTS

The results revealed that cisplatin plus olaparib significantly reduced tumor volume in mice subjected to subcutaneous tumor transplantation, and the expression of miR-125a-3p significantly increased with this treatment combination. The overexpression of miR-125a-3p could inhibit cell migration, invasion and induces cell cycle arrest.

CONCLUSION

On the whole, the present study demonstrates that the increased expression of miR-125a-3p induces DNA damage and senescence in ovarian cancer cells, which enhances the therapeutic sensitivity.

Targeted inhibition of the ATR/CHK1 pathway overcomes resistance to olaparib and dysregulates DNA damage response protein expression in BRCA2MUT ovarian cancer cells

Olaparib is a PARP inhibitor (PARPi) approved for targeted treatment of ovarian cancer (OC). However, its efficacy is impeded by the inevitable occurrence of resistance. Here, we investigated whether the cytotoxic activity of olaparib could be synergistically enhanced in olaparib-resistant OC cells with BRCA2 reversion mutation by the addition of inhibitors of the ATR/CHK1 pathway. Moreover, we provide insights into alterations in the DNA damage response (DDR) pathway induced by combination treatments. Antitumor activity of olaparib alone or combined with an ATR inhibitor (ATRi, ceralasertib) or CHK1 inhibitor (CHK1i, MK-8776) was evaluated in OC cell lines sensitive (PEO1, PEO4) and resistant (PEO1-OR) to olaparib. Antibody microarrays were used to explore changes in expression of 27 DDR-related proteins. Olaparib in combination with ATR/CHK1 inhibitors synergistically induced a decrease in viability and clonogenic survival and an increase in apoptosis mediated by caspase-3/7 in all OC cells. Combination treatments induced cumulative alterations in expression of DDR-related proteins mediating distinct DNA repair pathways and cell cycle control. In the presence of ATRi and CHK1i, olaparib-induced upregulation of proteins determining cell fate after DNA damage (PARP1, CHK1, c-Abl, Ku70, Ku80, MDM2, and p21) was abrogated in PEO1-OR cells. Overall, the addition of ATRi or CHK1i to olaparib effectively overcomes resistance to PARPi exerting anti-proliferative effect in BRCA2MUT olaparib-resistant OC cells and alters expression of DDR-related proteins. These new molecular insights into cellular response to olaparib combined with ATR/CHK1 inhibitors might help improve targeted therapies for olaparib-resistant OC.

Advances and challenges in thyroid cancer: The interplay of genetic modulators, targeted therapies, and AI-driven approaches

Thyroid cancer continues to exhibit a rising incidence globally, predominantly affecting women. Despite stable mortality rates, the unique characteristics of thyroid carcinoma warrant a distinct approach. Differentiated thyroid cancer, comprising most cases, is effectively managed through standard treatments such as thyroidectomy and radioiodine therapy. However, rarer variants, including anaplastic thyroid carcinoma, necessitate specialized interventions, often employing targeted therapies. Although these drugs focus on symptom management, they are not curative. This review delves into the fundamental modulators of thyroid cancers, encompassing genetic, epigenetic, and non-coding RNA factors while exploring their intricate interplay and influence. Epigenetic modifications directly affect the expression of causal genes, while long non-coding RNAs impact the function and expression of micro-RNAs, culminating in tumorigenesis. Additionally, this article provides a concise overview of the advantages and disadvantages associated with pharmacological and non-pharmacological therapeutic interventions in thyroid cancer. Furthermore, with technological advancements, integrating modern software and computing into healthcare and medical practices has become increasingly prevalent. Artificial intelligence and machine learning techniques hold the potential to predict treatment outcomes, analyze data, and develop personalized therapeutic approaches catering to patient specificity. In thyroid cancer, cutting-edge machine learning and deep learning technologies analyze factors such as ultrasonography results for tumor textures and biopsy samples from fine needle aspirations, paving the way for a more accurate and effective therapeutic landscape in the near future.