The effect of metformin when combined with neoadjuvant chemotherapy in breast cancer patients

Metformin as anticancer agent and adjuvant in cancer combination therapy: Current progress and future prospect

Metformin, as the preferred antihyperglycemic drug for type 2 diabetes, has been found to have a significant effect in inhibiting tumor growth in recent years. However, metformin alone in cancer treatment has the disadvantages of high dose concentrations and few targeted cancer types. Increasing studies have confirmed that metformin can be used in combination with conventional anticancer therapy to obtain more promising clinical benefits, which is expected to be rapidly transformed and applied in clinic. Some combination therapy strategies including metformin combined with chemotherapy, radiotherapy, targeted therapy and immunotherapy have been proven to have more significant antitumor effects and longer survival time than monotherapy. In this review, we summarize the synergistic antitumor effects and mechanisms of metformin in combination with other current conventional anticancer therapies. In addition, we update the research progress and the latest prospect of the metformin-combined application in the cancer treatment. This work could provide more evidence and future direction for the clinical application of metformin in antitumor.

Assessment of novel prognostic biomarkers to predict pathological complete response in patients with non-metastatic triple-negative breast cancer using a window of opportunity design

Background

Triple-negative breast cancer (TNBC) includes approximately 20% of all breast cancer and is characterized by its aggressive nature, high recurrence rates, and visceral metastasis. Pathological complete response (pCR) is an established surrogate endpoint for survival. The window of opportunity studies provide valuable information on the disease biology prior to definitive treatment.

Objectives

To study the association of dynamic change in pathological, imagining, and genomic biomarkers that can prognosticate pCR. The study aims to develop a composite prognostic score.

Design

Clinical, interventional, and prognostic biomarker study using the novel window of opportunity design.

Methods

The study aims to enroll 80 treatment-naïve, pathologically confirmed TNBC patients, administering a single dose of paclitaxel and carboplatin during the window period before neoadjuvant chemotherapy (NACT). Tumor tissue will be obtained through a tru-cut biopsy, and positron emission tomography and computed tomography scans will be performed for each patient at two time points aiming to evaluate biomarker alterations. This will be followed by the administration of standard dose-dense NACT containing anthracyclines and taxanes, with the study culminating in surgery to assess pCR.

Results

The study would develop a composite prognostic risk score derived from the dynamic change in the Ki-67, tumor-infiltrating lymphocytes, Standardized Uptake Value (SUV max), Standardized Uptake Value for lean body mass (SUL max), and gene expression level pre- and post-intervention during the window period prior to the start of definitive treatment. This outcome will aid in categorizing the disease biology into risk categories.

Trial registration

The current study is approved by the Institutional Ethics Committee [Ethics: Protocol. no. JIP/IEC/2020/019]. This study was registered with ClinicalTrials.gov [CTRI Registration: CTRI/2022/06/043109].

Conclusion

The validated biomarker score will help to personalize NACT protocols in patients in TNBC planned for definitive treatment.

Acidosis activates breast cancer ferroptosis through ZFAND5/SLC3A2 signaling axis and elicits M1 macrophage polarization

Acidosis is involved in multiple pathways in tumor cells and immune cells among the tumor microenvironment (TME). Ferroptosis is a nonapoptotic and iron-dependent form of cell death characterized by accumulation of lipid peroxidation involved in various cancers. The role of ferroptosis in the breast cancer (BC) acidic microenvironment remains unrevealed. Here, we reported that short-term acidosis induced ferroptosis of BC cells in the zinc finger AN1-type domain 5 (ZFAND5)/solute carrier family 3 member 2 (SLC3A2) dependent manner to suppress tumor growth using in silico and multiple biological methods. Mechanistically, we demonstrated that short-term acidosis increased total/lipid reactive oxygen species (ROS) level, decreased glutathione (GSH) level and induced the morphological changes of mitochondria. Specifically, acidosis restrained the protein stability of SLC3A2 by promoting its ubiquitination process. The prognostic analysis showed that higher expression of ZFAND5 and lower expression of SLC3A2 were correlated with longer overall survival of BC patients, respectively. Furthermore, in combination with ferroptosis agonist metformin, short-term acidosis could synergistically inhibit viability and enhance the ferroptosis of BC cells. Meanwhile, by the exploration of immune cells, short-term acidosis also induced M1 macrophage polarization, triggering processes of phagocytosis and ferroptosis in BC cells. This study demonstrated that short-term acidosis induced BC cell ferroptosis through ZFAND5/SLC3A2 signaling axis and promoted phagocytosis and ferroptosis of BC cells with M1 macrophage polarization, which might be a new mechanism for BC therapy.

Mint3-depletion-induced energy stress sensitizes triple-negative breast cancer to chemotherapy via HSF1 inactivation

Given the lack of therapeutic targets, the conventional approach for managing triple-negative breast cancer (TNBC) involves the utilization of cytotoxic chemotherapeutic agents. However, most TNBCs acquire resistance to chemotherapy, thereby lowering the therapeutic outcome. In addition to oncogenic mutations in TNBC, microenvironment-induced mechanisms render chemoresistance more complex and robust in vivo. Here, we aimed to analyze whether depletion of Munc18-1 interacting protein 3 (Mint3), which activates hypoxia-inducible factor 1 (HIF-1) during normoxia, sensitizes TNBC to chemotherapy. We found that Mint3 promotes the chemoresistance of TNBC in vivo. Mint3 depletion did not affect the sensitivity of human TNBC cell lines to doxorubicin and paclitaxel in vitro but sensitized tumors of these cells to chemotherapy in vivo. Transcriptome analyses revealed that the Mint3-HIF-1 axis enhanced heat shock protein 70 (HSP70) expression in tumors of TNBC cells. Administering an HSP70 inhibitor enhanced the antitumor activity of doxorubicin in TNBC tumors, similar to Mint3 depletion. Mint3 expression was also correlated with HSP70 expression in human TNBC specimens. Mechanistically, Mint3 depletion induces glycolytic maladaptation to the tumor microenvironment in TNBC tumors, resulting in energy stress. This energy stress by Mint3 depletion inactivated heat shock factor 1 (HSF-1), the master regulator of HSP expression, via the AMP-activated protein kinase/mechanistic target of the rapamycin pathway following attenuated HSP70 expression. In conclusion, Mint3 is a unique regulator of TNBC chemoresistance in vivo via metabolic adaptation to the tumor microenvironment, and a combination of Mint3 inhibition and chemotherapy may be a good strategy for TNBC treatment.

The Effect of Metformin on Chemotherapy-Induced Toxicities in Non-diabetic Breast Cancer Patients: A Randomised Controlled Study

BACKGROUND AND OBJECTIVE

Breast cancer patients treated with adriamycin-cyclophosphamide plus paclitaxel (AC-T) are often challenged with serious adverse effects for which no effective therapies are available. Here, we investigated whether metformin, an antidiabetic drug with additional pleiotropic effects could favourably offset AC-T induced toxicities.

PATIENTS AND METHODS

Seventy non-diabetic breast cancer patients were randomised to receive either AC-T (adriamycin 60 mg/m² + cyclophosphamide 600 mg/m² × 4 cycles Q21 days, followed by weekly paclitaxel 80 mg/m² × 12 cycles) alone or AC-T plus metformin (1700 mg/day). Patients were assessed regularly after each cycle to record the incidence and severity of adverse events based on the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE), version 5.0. Moreover, baseline echocardiography and ultrasonography were done and repeated after the end of neoadjuvant therapy.

RESULTS

Addition of metformin to AC-T resulted in significantly less incidence and severity of peripheral neuropathy, oral mucositis, and fatigue (p < 0.05) compared to control arm. Moreover, the left ventricular ejection fraction (LVEF%) in the control arm dropped from a mean of 66.69 ± 4.57 to 62.2 ± 5.22% (p = 0.0004) versus a preserved cardiac function in the metformin arm (64.87 ± 4.84 to 65.94 ± 3.44%, p = 0.2667). Furthermore, fatty liver incidence was significantly lower in metformin compared with control arm (8.33% vs 51.85%, p = 0.001). By contrast, haematological disturbances caused by AC-T were preserved after concurrent metformin administration (p > 0.05).

CONCLUSION

Metformin offers a therapeutic opportunity for controlling toxicities caused by neoadjuvant chemotherapy in non-diabetic breast cancer patients.

TRIAL REGISTRATION

This randomised controlled trial was registered on November 20, 2019 in ClinicalTrials.gov under registration number: NCT04170465.

How Advanced are Cancer Immuno-Nanotherapeutics? A Comprehensive Review of the Literature

Cancer is a broad term for a group of diseases involving uncontrolled cell growth and proliferation. There is no cure for cancer despite recent significant improvements in screening, treatment, and prevention approaches. Among the available treatments, immunotherapy has been successful in targeting and killing cancer cells by stimulating or enhancing the body's immune system. Antibody-based immunotherapeutic agents that block immune checkpoint proteins expressed by cancer cells have shown promising results. The rapid development of nanotechnology has contributed to improving the effectiveness and reducing the adverse effects of these anti-cancer immunotherapeutic agents. Recently, engineered nanomaterials have been the focus of many state-of-The-art approaches toward effective cancer treatment. In this review, the contribution of various nanomaterials such as polymeric nanoparticles, dendrimers, microspheres, and carbon nanomaterials in improving the efficiency of anti-cancer immunotherapy is discussed as well as nanostructures applied to combination cancer immunotherapy.

Effects of metformin on human bone-derived mesenchymal stromal cell-breast cancer cell line interactions

Metformin is used to treat patients with type 2 diabetes mellitus and was found to lower the incidence of cancer. Bone metastasis is a common impairment associated with advanced breast cancer. The present study investigated the effects of metformin on human bone-derived mesenchymal stromal cells (BM-MSC)—breast cancer cell line interactions. BM-MSCs grown from box chisels were tested for growth-stimulating and migration-controlling activity on four breast cancer cell lines either untreated or after pretreatment with metformin. Growth stimulation was tested in MTT tests and migration in scratch assays. Furthermore, the expression of adipokines of BM-MSCs in response to metformin was assessed using Western blot arrays. Compared to breast cancer cell lines (3.6 ± 1.4% reduction of proliferation), 500 µM metformin significantly inhibited the proliferation of BM-MSC lines (mean 12.3 ± 2.2 reduction). Pretreatment of BM-MSCs with metformin showed variable effects of the resulting conditioned media (CM) on breast cancer cell lines depending on the specific BM-MSC—cancer line combination. Metformin significantly reduced the migration of breast cancer cell lines MDA-MB-231 and MDA-MB-436 in response to CM of drug-pretreated BM-MSCs. Assessment of metformin-induced alterations in the expression of adipokines by BM-MSC CM indicated increased osteogenic signaling and possibly impairment of metastasis. In conclusion, the anticancer activities of metformin are the result of a range of direct and indirect mechanisms that lower tumor proliferation and progression. A lower metformin-induced protumor activity of BM-MSCs in the bone microenvironment seem to contribute to the positive effects of the drug in selected breast cancer patients.

Metformin Downregulates the Expression of Epidermal Growth Factor Receptor Independent of Lowering Blood Glucose in Oral Squamous Cell Carcinoma

PURPOSE

Type 2 diabetes mellitus (T2DM) is among the risk factors for the occurrence and development of cancer. Metformin is a potential anticancer drug. Epidermal growth factor receptor (EGFR) plays an important role in the progression of oral squamous cell carcinoma(OSCC), but the relationship between metformin and EGFR expression in OSCC remains unclear.

METHODS

This study involved the immunohistochemical detection of EGFR expression in cancer tissues of patients with T2DM and OSCC. The patients were divided into groups according to whether they were taking metformin for the treatment of T2DM, and the expression of EGFR in different groups was compared. Correlation analysis between the expression of EGFR and the fluctuation value of fasting blood glucose (FBG) was carried out. Immunohistochemistry was used to detect the expression of EGFR in cancer tissues of patients with recurrent OSCC. These patients had normal blood glucose and took metformin for a long time after the first operation.

RESULTS

EGFR expression in T2DM patients with OSCC taking metformin was significantly lower than that in the non-metformin group. FBG fluctuations were positively correlated with the expression of EGFR in the OSCC tissues of the non-metformin group of T2DM patients. In patients with recurrent OSCC with normal blood glucose, metformin remarkably reduced the expression of EGFR in recurrent OSCC tissues.

CONCLUSION

Metformin may regulate the expression of EGFR in a way that does not rely on lowering blood glucose. These results may provide further evidence for metformin in the treatment of OSCC.