Role of chemotherapy in breast cancer

Natural products derived from medicinal plants and microbes might act as a game-changer in breast cancer: a comprehensive review of preclinical and clinical studies

Breast cancer (BC) is the most prevalent neoplasm among women. Genetic and environmental factors lead to BC development and on this basis, several preventive - screening and therapeutic interventions have been developed. Hormones, both in the form of endogenous hormonal signaling or hormonal contraceptives, play an important role in BC pathogenesis and progression. On top of these, breast microbiota includes both species with an immunomodulatory activity enhancing the host's response against cancer cells and species producing proinflammatory cytokines associated with BC development. Identification of novel multitargeted therapeutic agents with poly-pharmacological potential is a dire need to combat advanced and metastatic BC. A growing body of research has emphasized the potential of natural compounds derived from medicinal plants and microbial species as complementary BC treatment regimens, including dietary supplements and probiotics. In particular, extracts from plants such as Artemisia monosperma Delile, Origanum dayi Post, Urtica membranacea Poir. ex Savigny, Krameria lappacea (Dombey) Burdet & B.B. Simpson and metabolites extracted from microbes such as Deinococcus radiodurans and Streptomycetes strains as well as probiotics like Bacillus coagulans and Lactobacillus brevis MK05 have exhibited antitumor effects in the form of antiproliferative and cytotoxic activity, increase in tumors' chemosensitivity, antioxidant activity and modulation of BC - associated molecular pathways. Further, bioactive compounds like 3,3'-diindolylmethane, epigallocatechin gallate, genistein, rutin, resveratrol, lycopene, sulforaphane, silibinin, rosmarinic acid, and shikonin are of special interest for the researchers and clinicians because these natural agents have multimodal action and act via multiple ways in managing the BC and most of these agents are regularly available in our food and fruit diets. Evidence from clinical trials suggests that such products had major potential in enhancing the effectiveness of conventional antitumor agents and decreasing their side effects. We here provide a comprehensive review of the therapeutic effects and mechanistic underpinnings of medicinal plants and microbial metabolites in BC management. The future perspectives on the translation of these findings to the personalized treatment of BC are provided and discussed.

A preliminary study to identify existing drugs for potential repurposing in breast cancer based on side effect profile

Breast cancer is the most commonly diagnosed cancer and the second leading cause of cancer-related death in women after lung cancer. The present study aims to identify potential drug candidates using the PROMISCUOUS database for breast cancer based on side effect profile and then proceed with in silico and in vitro studies. PROMISCUOUS database was used to construct a group of drugs that share maximum side effects with letrozole. Based on the existing literature, ropinirole, risperidone, pregabalin, and gabapentin were selected for in silico and in vitro studies. The molecular docking was carried out using AUTODOCK 4.2.6. MCF-7 cell line was used to evaluate the anti-cancer activity of the selected drugs. PROMISCUOUS database revealed that as many as 23 existing drugs shared between 62 and 79 side-effects with letrozole. From docking result, we found that, ropinirole showed a good binding affinity (-7.7 kcal/mol) against aromatase compared to letrozole (-7.1 kcal/mol) which was followed by gabapentin (-6.4 kcal/mol), pregabalin (-5.7 kcal/mol) and risperidone (-5.1 kcal/mol). From the in vitro results, ropinirole and risperidone showed good anti-cancer activity of IC₅₀ with 40.85±11.02 μg/ml and 43.10±9.58 μg/ml cell viability. Based on this study results and existing literature we conclude that risperidone, pregabalin, and gabapentin are not ideal candidates for repurposing in breast cancer but ropinirole could be an excellent choice for repurposing in breast cancer after further studies.

Debio-0932, a second generation oral Hsp90 inhibitor, induces apoptosis in MCF-7 and MDA-MB-231 cell lines

Heat shock protein 90 (Hsp90) is a key chaperone that is abnormally expressed in cancer cells, and therefore, designing novel compounds to inhibit chaperone activities of the Hsp90 is a promising therapeutic approach for cancer drug discovery. Debio-0932 is a second-generation Hsp90 inhibitor that exhibited promising anticancer activity against a wide variety of cancer types with a strong binding affinity for Hsp90 and high oral bioavailability. Anticancer activities of the Debio-0932 were tested in MCF-7 and MDA-MB-231 cell lines. Molecular docking results indicated that Debio-0932 was selectively bound to the ATP binding pocket of the Hsp90 with an estimated free energy of binding - 7.24 kcal/mol. Antiproliferative activity of Debio-0932 was determined by XTT assay and Debio-0932 exhibited a cytotoxic effect on MCF-7 and MDA-MB-231 cells in a time and dose-depended manner. Apoptosis inducer role of Debio-0932 was evaluated in MCF-7 and MDA-MB-231 cells with fluorometric apoptosis/necrosis detection kit. Treatment with Debio-0932 stimulated apoptosis in both breast cancer cell lines. mRNA and protein expression levels of Bax, Bcl-2 and Casp-9 were determined in MCF-7 and MDA-MB-231 cells by RT-PCR and Western blotting respectively. Debio-0932 stimulated the down-regulation of anti-apoptotic protein Bcl-2 and the up-regulation of apoptotic protein Bax and cleavage of Casp-9 in cancer cells. Moreover, the anti-invasive potential of Debio-0932 was evaluated in endothelial cells (HUVEC) by wound-healing assay. Debio-0932 decreased the migration of HUVEC cells as compared to the control group. These results indicate that Debio-0932 is a promising compound to treat triple-negative breast cancer and hormone receptor-positive breast cancer, and their metastases.

LIFR-AS1 modulates Sufu to inhibit cell proliferation and migration by miR-197-3p in breast cancer

Numerous evidence has recently demonstrated that long non-coding RNAs (lncRNAs) play vital roles in the oncogenesis and development of a wide range of human neoplasms. Leukemia inhibitory factor receptor antisense RNA 1 (LIFR-AS1), a novel cancer-related lncRNA, has been reported to be under-expressed in breast cancer and associated with poor prognosis. However, the exact role of LIFR-AS1 in breast cancer remains largely unclear. The present study aimed to investigate the biological role of LIFR-AS1 in breast cancer and clarify the potential molecular mechanisms. In the present study, we found that LIFR-AS1 was significantly down-regulated in both tissues and cell lines. Furthermore, over-expression of LIFR-AS1 inhibited breast cancer cell proliferation, colony formation, migration and invasion, whereas knockdown of LIFR-AS1 promoted breast cancer cell proliferation, colony formation, migration and invasion. Moreover, LIFR-AS1 was observed to up-regulate suppressor of fused gene (Sufu) expression by competitively binding to miR-197-3p in breast cancer cells. Notably, miR-197-3p inhibitor reversed the promoting effects of LIFR-AS1 knockdown on breast cancer cell proliferation, colony formation, migration and invasion. Additionally, LIFR-AS1 knockdown promoted tumor growth in vivo. To sum up, our results imply the tumor-suppressing role of LIFR-AS1 in breast cancer.

Efficacy and safety of TE/TEC/intensive paclitaxel neoadjuvant chemotherapy for the treatment of breast cancer

Efficacy and safety of paclitaxel/docetaxel + epirubicin (TE), paclitaxel/docetaxel + epirubicin + cytoxan (TEC) and intensive paclitaxel (IP) neoadjuvant chemotherapy (NCT) were compared for the treatment of breast cancer. The clinical data of 326 patients with stage II–III unilateral primary breast cancer treated in Shengjing Hospital of China Medical University from January 2012 to April 2016 were retrospectively analyzed. All patients received NCT for 4 cycles, including 115 cases of TE group, 109 cases of TEC group, and 102 cases of paclitaxel weekly group. The clinical efficacy was evaluated and complete response (CR) + partial response (PR) indicated clinically effective. The pathological effect was evaluated and the grade III+IV+V indicated pathologically effective. The rates of clinical efficacy and pathological CR (pCR) were compared, and the incidence of adverse reactions was also observed. The effects of different molecular typing on clinical efficacy and pCR were compared. Our results showed that the clinical effective rates in TE, TEC and IP groups were 80.9, 89.0 and 77.5%, respectively, and there were no statistically significant differences (P=0.074). The pCR rates in the three groups were 9.57, 8.26 and 5.88%, respectively, and the differences were not statistically significant (P=0.602). The incidence rate of neutropenia was statistically different among the three groups of patients (P<0.001), which was the highest in TEC group and the lowest in IP group. There were no statistically significant differences in the incidence rates of adverse reactions (P>0.05). Estrogen receptor (ER)-negative, progesterone receptor (PR)-negative and human epidermal growth factor receptor-2 (HER-2)-positive states were significantly correlated with the high clinical effective rate and high pCR rate (P<0.05). In conclusion, IP has the lowest incidence rate of neutropenia. Additionally, ER-negative, PR-negative and HER-2-positive states are significantly correlated with the high clinical effective rate and high pCR rate.

Capecitabine–docetaxel combination treatment

Metastatic breast cancer develops in approximately 50% of women diagnosed with breast cancer. The optimal treatment for patients with metastatic breast cancer has yet to be defined, owing to the heterogeneity of this group and the available agents. Patients with metastatic breast cancer often receive single-agent treatment in sequence as it is unclear whether combination therapy with cytotoxic drugs offers an overall disease-free survival benefit and single agents may offer less toxicity. The advantages of combination cytotoxic therapies have included higher response rates. However, such trials have not stratified on rapidity of disease progression or on tumor bulk. In previous studies, docetaxel is one of the few cytotoxic agents to demonstrate a survival benefit in anthracycline-resistant patients and thus it has become a vital component of cytotoxic therapy. Capecitabine is also an important oral drug and has demonstrated activity in patients pretreated with anthracyclines and taxanes. Recent preclinical and clinical trials of this combination have demonstrated an increased time to tumor progression and overall survival benefit. Paclitaxel combined with gemcitabine has been compared with docetaxel plus capecitabine, with similar response rates and survival benefits. As patients on these trials have not received uniform crossover to the other active agent, whether or not the combination therapy offers an advantage for the entire cohort of metastatic patients or may be indicated for specific subgroups remains uncertain. Combination treatments may be preferable to sequential therapy for patients requiring urgent reduction in their tumor burden. Combinations of cytotoxic agents in combination with biological agents are currently being defined.

Telomeres: prognostic markers for solid tumors

Solid tumors continue to affect millions of people worldwide. Increasingly sophisticated diagnostic tools contribute to the high incidence rates for some tumor types, and treatment options continue to expand. However, the progression of solid tumors represents a challenge for the appropriate treatment of individual patients because of the relative inaccuracy of current prognostic markers, including the widely used Tumor-Nodes-Metastasis (TNM) staging system, to predict the course of disease. As a result, both over- and undertreatment are clinical realities in the management of patients diagnosed with solid tumors. Therefore, population-based screening programs that increase the overall cancer incidence rates are controversial, as they may do little to improve the patient's quality of life. Consequently, there is a strong need to develop novel and independent markers of prognosis. In this context, we review the use of telomeres as prognostic markers for solid tumors, including cancers from lung, breast, prostate, colon, brain and head and neck. Telomeric sequences, the repetitive DNA at the end of human chromosomes, are mediators of genomic stability and can undergo length alterations during tumor initiation and progression. In a number of studies reviewed here, these alterations, measured as telomere attrition and elongation, have been shown either to be associated with clinical markers of disease progression or to be independent markers of cancer prognosis. We conclude from these studies that careful assessment of telomere length or its proxies, such as telomere DNA content, will be part of novel risk assessment and prognostic modalities for patients with solid tumors.