Targeted Therapies in Breast Cancer: Implications for Advanced Oncology Practice

Rapamycin Antagonizes BCRP-Mediated Drug Resistance Through the PI3K/Akt/mTOR Signaling Pathway in mPRα-Positive Breast Cancer

Purpose

Overexpression of breast cancer (BCa) resistance protein (BCRP) is detected in approximately 30% of BCa cases. BCRP indicates a poor response to chemotherapy, and it has become a classic target to overcome drug-resistant tumor cells. In this study, we aimed to explore the mechanism of BCRP overexpression and a strategy to reverse this overexpression in invasive BCa.

Methods

BCRP expression in BCa tissues was determined by immunohistochemistry. GSE25066 was downloaded from the NCBI GEO database. Western blot was used to determine the expression of key molecules in vitro. Cell counting kit-8 assays were used to assess the drug response of BCa cells.

Results

Our results suggested that BCRP is an independent risk factor for BCa. We further established that upon 17α-PG binding, membrane progesterone receptor α (mPRα) promoted BCRP expression via the PI3K/Akt/mTOR signaling pathway. mPRα physically interacted with p-Akt1 S473. Moreover, rapamycin, an inhibitor of mTOR complex 1 (mTORC1), downregulated BCRP expression and enhanced the effects of particular drugs, including doxorubicin and paclitaxel.

Conclusion

BCRP is a potential biomarker of poor prognosis in BCa. BCRP expression is regulated by 17α-PG in mPRα-positive BCa cells through the PI3K/Akt/mTOR signaling pathway. Rapamycin might enhance the therapeutic effect of chemotherapy agents in mPRα-positive MDA-MB-453/BCRP cells and might be a therapeutic option for mPRα-positive invasive BCa with BCRP overexpression.

Understanding and treating solid tumor-related disseminated intravascular coagulation in the "era" of targeted cancer therapies

A systemic activation of blood coagulation is usually present in many clinical conditions including the infectious or inflammatory ones and malignant disease as well. Depending upon circumstances, patients suffering from acute decompensated disseminated intravascular coagulation may be managed by a medical oncologist and either an internist or a physician working in an emergency and/or intensive care unit. In some cases, for example, the indolent ones, the activation of coagulation might not be easily detected by routine laboratory tests and not lead to clinical manifestations. Such a chronically activated intravascular coagulation can progress toward an overt decompensated disseminated intravascular coagulation. Traditional therapy of decompensated disseminated intravascular coagulation is based on reversing the underlying triggering disease and providing patients with adequate supportive treatment. The dilemma for the oncologist is whether or not the trigger cause can be treated and amended with a specific antineoplastic treatment, without worsening the consumption of platelets and the risk of bleeding. In light of the availability of new targeted therapies, the main criteria that should drive the strategy against solid cancer-related disseminated intravascular coagulation will be discussed.

HER2-Orientated Therapy in Early and Metastatic Breast Cancer

Due to the enhanced understanding of molecular oncology and signaling pathways in breast cancer (BC), therapy management has undergone a major transformation, especially with the emergence of treatment tailored to individual disease characteristics. In the case of HER2-positive early or metastatic BC, targeted therapies are well established and remain a major focus of ongoing research. The introduction of anti-HER2 biologicals such as trastuzumab, pertuzumab, and T-DM1 has made targeted and personalized treatment possible and has clearly improved disease-free and overall survival in patients with HER2-positive BC. Moreover, neoadjuvant chemotherapy represents a well-established and often favored option for patients with operable BC and a clear indication for postoperative chemotherapy (such as HER2-positive BC). Other trials are trying to identify additional surrogate markers for therapy response and clinical outcome in the neoadjuvant setting and that way open up new perspectives with a possible de-escalation of classical treatment in favor of targeted therapy.

Association between FOXM1 and hedgehog signaling pathway in human cervical carcinoma by tissue microarray analysis

Forkhead box M1 (FOXM1) and hedgehog (Hh) signaling pathway are implicated in the formation and development of human tumors, including cervical cancer. Previous studies have indicated that FOXM1 may be a downstream target gene of the Hh signaling pathway, but their association in cervical cancer is largely unknown. In the present study, the expression of FOXM1 and Hh signaling molecules was evaluated by immunohistochemical analysis in a tissue microarray that contained 70 cervical cancer tissues and 10 normal cervical tissues. In addition, the association of these molecules with clinicopathological parameters, and the association between FOXM1 and various molecules involved in the Hh signaling pathway was investigated. The results indicated that FOXM1 and Hh signaling molecules were overexpressed in cervical cancer tissues. The protein expression levels of FOXM1, glioma-associated oncogene 1 (GLI1) and smoothened (SMO) correlated with the clinical stage of the tumors, while the protein expression levels of Sonic Hh (SHh), patched 1 (PTCH1) and GLI1 correlated with the pathological grade of the tumors. The expression levels of GLI1 were lower in tissues without lymph node metastasis than in tissues with lymph node metastasis. In addition, FOXM1 expression correlated with GLI1, SHh and PTCH1 expression in cancer tissues. These findings confirmed the participation of FOXM1 and the Hh signaling pathway in cervical cancer. Furthermore, the finding that FOXM1 may be a downstream target gene of the Hh signaling pathway in cervical cancer provides a potential novel diagnostic and therapeutic target for cervical cancer.