A dose escalation trial of adjuvant cyclophosphamide and epirubicin in combination with 5-fluorouracil using G-CSF support for premenopausal women with breast cancer involving four or more positive nodes

Inhibition of 6-Phosphogluconate Dehydrogenase Reverses Epirubicin Resistance Through Metabolic Reprograming in Triple-Negative Breast Cancer Cells

At present, chemotherapy is the most effective strategy for treating triple-negative breast cancer (TNBC), but its efficacy was limited by the development of chemo-resistance. The exact mechanism of chemoresistance still remains unclear. This study aims to examine whether 6-phosphogluconate dehydrogenase (6PGD), a key enzyme in the oxidative pentose phosphate pathway (PPP), could promote the resistance of TNBC cells to epirubicin. A TNBC epirubicin-resistant cell line was developed by increasing concentration and the effectiveness was tested. The expression and knockdown efficiency of 6PGD were further validated by performing quantitative real-time PCR (qPCR) and Western blot. The effects of 6PGD on parental and drug-resistant TNBC cell lines were verified based on proliferation and apoptosis experiments. Finally, nicotinamide adenine dinucleotide phosphate (NADPH) and lactate quantitative experiments were performed to examine the mechanism of 6PGD in promoting drug resistance. Epirubicin-resistant cancer cells exhibited a higher level of 6PGD in contrast to epirubicin-sensitive cells. In addition, 6PGD inhibited by genetic and pharmacological approaches significantly suppressed the growth and survival of both epirubicin-sensitive and epirubicin-resisteant TNBC cells. It should be noted that 6PGD inhibition sensitized epirubicin-resistant TNBC cells to epirubicin treatment. Moreover, it was also found that the levels of NADPH and lactate increased in epirubicin-resistant TNBC cells but decreased in response to 6PGD inhibition. The present results indicated that 6PGD inhibition disrupted metabolic reprogramming in epirubicin-resistant TNBC cells. Our work demonstrated that 6PGD inhibition reversed the resistance of TNBC cells to epirubicin, providing an alternative therapeutic choice to tackle the challenge of epirubicin resistance in TNBC treatment.

Triple negative breast cancer: approved treatment options and their mechanisms of action

PURPOSE

Breast cancer, the most prevalent cancer worldwide, consists of 4 main subtypes, namely, Luminal A, Luminal B, HER2-positive, and Triple-negative breast cancer (TNBC). Triple-negative breast tumors, which do not express estrogen, progesterone, and HER2 receptors, account for approximately 15-20% of breast cancer cases. The lack of traditional receptor targets contributes to the heterogenous, aggressive, and refractory nature of these tumors, resulting in limited therapeutic strategies.

METHODS

Chemotherapeutics such as taxanes and anthracyclines have been the traditional go to treatment regimens for TNBC patients. Paclitaxel, docetaxel, doxorubicin, and epirubicin have been longstanding, Food and Drug Administration (FDA)-approved therapies against TNBC. Additionally, the FDA approved PARP inhibitors such as olaparib and atezolizumab to be used in combination with chemotherapies, primarily to improve their efficiency and reduce adverse patient outcomes. The immunotherapeutic Keytruda was the latest addition to the FDA-approved list of drugs used to treat TNBC.

RESULTS

The following review aims to elucidate current FDA-approved therapeutics and their mechanisms of action, shedding a light on the various strategies currently used to circumvent the treatment-resistant nature of TNBC cases.

CONCLUSION

The recent approval and use of therapies such as Trodelvy, olaparib and Keytruda has its roots in the development of an understanding of signaling pathways that drive tumour growth. In the future, the emergence of novel drug delivery methods may help increase the efficiency of these therapies whiel also reducing adverse side effects.

A randomized, multi-center, open-label, phase II study of once-per-cycle DA-3031, a biosimilar pegylated G-CSF, compared with daily filgrastim in patients receiving TAC chemotherapy for early-stage breast cancer

BACKGROUNDS

A pegylated form of recombinant granulocyte-colony stimulating factor (G-CSF) was developed for prophylactic use in breast cancer. The aim of this study was to evaluate the efficacy and safety of once-per-cycle DA-3031 in patients receiving chemotherapy for breast cancer.

METHODS

A total of 61 patients receiving docetaxel, doxorubicin, and cyclophosphamide (TAC) chemotherapy were randomized in cycle 1 to receive daily injections of filgrastim (100 μg/m(2)) or a single subcutaneous injection of pegylated filgrastim DA-3031 at a dose of either 3.6 mg or 6 mg.

RESULTS

The mean duration of grade 4 neutropenia in cycle 1 was comparable among the treatment groups (2.48, 2.20, and 2.05 days for filgrastim, DA-3031 3.6 mg and 6 mg, respectively; P=0.275). No statistically significant differences were observed in the incidence of febrile neutropenia between the treatment groups (9.5 %, 15.0 %, and 5.0 % for filgrastim, DA-3031 3.6 mg and 6 mg, respectively; P=0.681) in cycle 1. The incidences of adverse events attributable to G-CSF were similar among the treatment groups.

CONCLUSIONS

Fixed doses of 3.6 mg or 6 mg DA-3031 have an efficacy comparable to that of daily injections of filgrastim in ameliorating grade 4 neutropenia in patients receiving TAC chemotherapy.

Epirubicin: is it like doxorubicin in breast cancer? A clinical review

Anthracyclines are among the most effective chemotherapy treatments available for various types of cancer. The anthracyclines commonly used in treatment of breast cancer are either epirubicin or doxorubicin. Epirubicin is an epimer of doxorubicin with important role in the chemotherapy treatment of both early and metastatic breast cancer. The efficacy of epirubicin is similar to doxorubicin while epirubicin has a different toxicity profile particularly in regard to cardiotoxicity. Epirubicin has been incorporated into most of the anthracycline containing chemotherapy combinations in well-conducted clinical trials involving large numbers of patients. It has also been investigated in studies involving the administration of epirubicin in dose-dense chemotherapy schedules. Short term follow up of dose-dense clinical trials demonstrated safety comparable to that of doxorubicin. This review summarizes published clinical trials investigating epirubicin in the treatment of early and advanced breast cancer.

Chemotherapy-induced weakness and fatigue in skeletal muscle: the role of oxidative stress

SIGNIFICANCE

Fatigue is one of the most common symptoms of cancer and its treatment, manifested in the clinic through weakness and exercise intolerance. These side effects not only compromise patient's quality of life (QOL), but also diminish physical activity, resulting in limited treatment and increased morbidity.

RECENT ADVANCES

Oxidative stress, mediated by cancer or chemotherapeutic agents, is an underlying mechanism of the drug-induced toxicity. Nontargeted tissues, such as striated muscle, are severely affected by oxidative stress during chemotherapy, leading to toxicity and dysfunction.

CRITICAL ISSUES

These findings highlight the importance of investigating clinically applicable interventions to alleviate the debilitating side effects. This article discusses the clinically available chemotherapy drugs that cause fatigue and oxidative stress in cancer patients, with an in-depth focus on the anthracycline doxorubicin. Doxorubicin, an effective anticancer drug, is a primary example of how chemotherapeutic agents disrupt striated muscle function through oxidative stress.

FUTURE DIRECTIONS

Further research investigating antioxidants could provide relief for cancer patients from debilitating muscle weakness, leading to improved quality of life.

Chronic toxicity of a novel recombinant human granulocyte colony-stimulating factor in rats

OBJECTIVE

To assess the severity and reversibility of the chronic toxicity of a novel recombinant human granulocyte colony-stimulating factor (rhG-CSFa) in rats and the dose-effect relationship.

METHODS

A total of 100 Sprague-Dawley rats (equal numbers of male and female) were randomly divided into five groups (20 rats in each group): four groups were treated with rhG-CSFa at 500, 100, 10, 1 µg/kg, respectively, and one group was treated with vehicle only to serve as the control. The rats were received subcutaneous injections of rhG-CSFa or vehicle daily for 13 weeks. During the course of the chronic toxicity study, the physical status, body weight, and food consumption were monitored. Half of the rats in each group (n = 10) were sacrificed after the last rhG-CSFa administration, and the other half were sacrificed at five weeks after the last rhG-CSFa administration. Urinalyses, blood biochemistry, hematological analysis, histopathological examination, and immunological tests were performed for each of the rats.

RESULTS

The hematological analyses revealed that the mean white blood cells count, neutrophils count, and neutrophils percentage were increased in male rats at the dose of 10 µg/kg or higher, and these were related with the biological activity of rhG-CSFa. Some small abnormalities were observed in the spleen of a few rats when used highest dose (500 µg/kg, a dosage of 200 folds higher than the normal clinical dosage), but these abnormalities were recovered within 5-week recovery period. No other rhG-CSFa-related abnormalities were observed in this chronic toxicity study.

CONCLUSION

No significant toxicity and immunogenicity are observed with rhG-CSFa administration to rats in the chronic toxicity studies.