Self-adaptive hydrogel for breast cancer therapy via accurate tumor elimination and on-demand adipose tissue regeneration

The irregular defects and residual tumor tissue after surgery are challenges for effective breast cancer treatment.Herein,a smart hydrogel with self-adaptable size and dual responsive cargos release was fabricated to treat breast cancer via accurate tumor elimination,on-demand adipose tissue regeneration and effective infection inhibition.The hydrogel consisted of thiol groups ended polyethylene glycol(SH-PEG-SH)and doxorubicin encapsulated mesoporous silica nanocarriers(DOX@MSNs)double crosslinked hyaluronic acid(HA)after loading of antibacterial peptides(AP)and adipose-derived stem cells(ADSCs).A pH-cleavable unsaturated amide bond was pre-introduced between MSNs and HA frame to perform the tumor-specific acidic environment dependent DOX@MSNs release,meanwhile an esterase degradable glyceryl dimethacrylate cap was grafted on MSNs,which contributed to the selective chemotherapy in tumor cells with over-expressed esterase.The bond cleavage between MSNs and HA would also cause the swelling of the hydrogel,which not only provide sufficient space for the growth of ADSCs,but allows the hydrogel to fully fill the irregular defects generated by surgery and residual tumor atrophy,resulting in the on-demand regeneration of adipose tissue.Moreover,the sustained release of AP could be simultaneously triggered along with the size change of hydrogel,which further avoided bacterial infection to promote tissue regeneration.

MicroRNAs in breast cancer and breast cancer stem cells and their potential for breast cancer therapy

The discovery of the first miRNA, lin-4, in Caenorhabditis elegans initiated a new era of miRNA biology. Sincethen, thousands of miRNAs annotated, many of which have have been identified and been shown to play roles in a variety of biological processes, including development, differentiation, apoptosis, proliferation, and cell death） Furthermore, growing evidence indicates that miRNA deregulation is a critical cause of cancer formation. The biogenesis, function, and potential application of miRNAs have become active areas of research. With the development of molecular biological technologies, such as northern blotting with radio-labeled probes, cloning, quantitative PCR, serial analysis of gene expression （SAGE）-based techniques, bead-based profiling methods, and oligonucleotide microarrays,2 it is possible to conduct miRNA research precisely and comprehensively. BIOGENESIS OF MICRORNAS MicroRNAs are derived from introns or exons of protein- coding and non-coding genes,3＇4 and are either transcribed by polymerase II as a long primary transcript （primary miRNA） or originate from the introns of mRNAs. Primary miRNAs are further processed by the Drosha microprocessor complex, which recognizes stem-looped secondary structures within primary miRNAs, resulting in the excision and release of-70 nucleotide hairpin precursors termed pre-miRNAs （precursor microRNAs）.5 The mirtron subclass of miRNAs, which are encoded in the introns of genes, generate pre-miRNAs directly from byproducts of intron splicing and disbranching events in the nucleus with the assistance of a ＂debranching enzyme＂.6 After being exported from the nucleus by exportin-5, the pre-miRNAs are subsequently cleaved by Dicer to release a 22-nucleaotide miRNA-miRNA duplex. One strand of this duplex is incorporated into the RNA-induced silencing complex （miRISC）, and eventually serves as a mature microRNA, while the other strand is degraded. The ＂seed＂ region of the mature microRNA （nucleotides 2-8 at the 5＇ end） can bind partially or completely to the 3＇UTR of specific protein-coding gene mRNAs.7＇8 MicroRNAs regulate their targets by directly cleaving mRNAs or inhibiting protein synthesis, depending on the degree of complementarity with the 3＇UTRs of their targets.4

Efficacy of capecitabine-based combination therapy and singleagent capecitabine maintenance therapy in patients with metastatic breast cancer

Objective： The purpose of this study was to observe the efficacy and toxicities of capecitabine-based chemotherapy and capecitabine monotherapy as maintenance therapy in the treatment of metastatic breast cancer（MBC）.Patients and methods： A total of 98 MBC patients were treated with capecitabine combined with vinorelbine（NX）. Results： The median number of treatment was 6 cycles（1-7 cycles）. There were two cases of complete remission（CR）, 58 partial remission, 27 stable disease（SD）, 11 progression disease. The overall response rate（ORR）（CR ＋ PR） was 61.2%. The clinical benefit rate（CBR） was 75.5%. Fifty of effective patients received with capecitabine monotherapy as maintenance therapy. The ORR（CR ＋ PR） was 4%. The CBR was 48%. The median progression-free survival（PFS） was 12 months. In maintenance therapy or not, the median post metastasis survival rate（MSR） was 63 and 28 months, respectively. In the combination therapy group, the major grade 3/4 toxicities included hand-foot syndrome（3.1%）, skin pigmentation（2.0%）, diarrhoea and abdominal distension（5.1%）, stomatitis（1.0%）, and leukopenia（20.4%）.Conclusions： Capecitabine-based combination therapy and single-agent capecitabine maintenance therapy were well tolerated and effective to MBC.

Searching for Better Outcomes among Patients with Metastatic Triple- Negative Breast Cancer – Do We Have Novel Options on the Treatment Landscape?

Triple-negative breast cancer(TNBC),which accounts for approximately 15%of breast cancers(BCs)is characterized by a lack of expression of the hormone receptors(HRs)(estrogen receptor(ER)and progesterone receptor(PR)),and human epidermal growth factor receptor 2(HER2).TNBC reveals very aggressive behavior and often leads to poor prognosis.Unfortunately,standard chemotherapy(CHT)is related to low response rates and short progression-free survival(PFS)in patients with metastatic TNBC,creating an unmet need.However,recent recognition of different molecular subtypes and mutations within TNBC has allowed exploring some innovative targeted therapies,bringing new hope for women suffering from TNBC.Currently,some promising systemic treatment options in this area have been developed,including targeted therapies,such as poly(ADP-ribose)polymerase(PARP)inhibitors,immune checkpoint inhibitors,antibody-drug conjugates,and AKT inhibitors.The aim of this mini-review is to address these novel treatment modalities and highlight the main directions for further research and clinical practice in the advanced or metastatic forms of TNBC.This article presents poly(ADP-ribose)polymerase(PARP)inhibitors(e.g.,olaparib,talazoparib,and valaparib for treatment of BRCA-mutated,HER2-negative metastatic BC),immune checkpoint inhibitors(atezolizumab and pembrolizumab),an antibody-drug conjugate(ADC)(sacituzumab govitecan),and AKT inhibitors(ipatasertib and capivasertib).A brief outline of the main clinical trials leading to the approval of these new medications has been provided.Moreover,this overview discusses the efficacy and safety of these innovative treatment options,focusing on women with metastatic TNBC.In addition,this paper comments on some recent considerations,regarding avenues of delivering care and conduct clinical trials in patients with BC,during the COVID-19 pandemic.

GD2+ cancer stem cells in triple-negative breast cancer:mechanisms of resistance to breast cancer therapies

Research has led to the development of tailored treatment options for different cancers in different patients.Despite some treatments being able to provide remarkable responses,nearly all current treatments encounter the same issue:resistance.Here,we discuss our experiences with how breast cancers resist therapies.The focus of our discussion revolves around the cancer stem cell subpopulation and their mechanisms for resistance.