Breast Cancers Activate Stromal Fibroblast-Induced Suppression of Progenitors in Adjacent Normal Tissue

Proteolytic remodeling of 3D bioprinted tumor microenvironments

In native tissue, remodeling of the pericellular space is essential for cellular activities and is mediated by tightly regulated proteases. Protease activity is dysregulated in many diseases, including many forms of cancer. Increased proteolytic activity is directly linked to tumor invasion into stroma, metastasis, and angiogenesis as well as all other hallmarks of cancer. Here we show a strategy for 3D bioprinting of breast cancer models using well-defined protease degradable hydrogels that can facilitate exploration of the multifaceted roles of proteolytic extracellular matrix remodeling in tumor progression. We designed a set of bicyclo[6.1.0]nonyne functionalized hyaluronan (HA)-based bioinks cross-linked by azide-modified poly(ethylene glycol) (PEG) or matrix metalloproteinase (MMP) degradable azide-functionalized peptides. Bioprinted structures combining PEG and peptide-based hydrogels were proteolytically degraded with spatial selectivity, leaving non-degradable features intact. Bioprinting of tumor-mimicking microenvironments using bioinks comprising human breast cancer cells (MCF-7) and fibroblast in hydrogels with different susceptibilities to proteolytic degradation shows that MCF-7 proliferation and spheroid size were significantly increased in protease degradable hydrogel compartments, but only in the presence of fibroblasts. In the absence of fibroblasts in the stromal compartment, cancer cell proliferation was reduced and did not differ between degradable and nondegradable hydrogels. The interactions between spatially separated fibroblasts and MCF-7 cells consequently resulted in protease-mediated remodeling of the bioprinted structures and a significant increase in cancer cell spheroid size, highlighting the close interplay between cancer cells and stromal cells in the tumor microenvironment and the influence of proteases in tumor progression.

Residual Risk of Ipsilateral Tumor Recurrence in Patients Who Achieved Clear Lumpectomy Margins After Repeated Resection

PURPOSE

Patients with breast cancer with positive lumpectomy margins have a two-fold increased risk of ipsilateral breast tumor recurrence (IBTR). This can be the result of either technically incomplete resection or the biological characteristics of the tumor that lead to a positive margin. We hypothesized that if achieving negative margins by re-excision nullifies the IBTR risk, then the increased risk is mainly attributed to the technical incompleteness of the initial surgeries. Thus, we investigated IBTR rates in patients with breast cancer who achieved clear margins after re-excision.

METHODS

We retrospectively reviewed patients who underwent breast lumpectomy for invasive breast cancer between 2004 and 2018 at a single institution, and investigated IBTR events.

RESULTS

Among 5,598 patients, 793 achieved clear margins after re-excision of their initial positive margins. During the median follow-up period of 76.4 months, 121 (2.2%) patients experienced IBTR. Patients who underwent re-excision to achieve negative margin experienced significantly higher IBTR rates compared to those achieving clear margin at first lumpectomy (10-year IBTR rate: 5.3% vs. 2.6% [25 vs. 84 events]; unadjusted p = 0.031, hazard ratio, 1.61, 95% confidence interval [CI], 1.04-2.48; adjusted p = 0.030, hazard ratio, 1.69, 95% CI, 1.05-2.72). This difference was more evident in patients aged < 50 years and those with delayed IBTR. Additionally, no statistically significant differences were observed in the spatial distribution of IBTR locations.

CONCLUSION

Patients who underwent re-excision for initial positive margins had an increased risk of IBTR, even after achieving a final negative margin, compared to patients with negative margins initially. This increased risk of IBTR is mostly observed in young patients and delayed cases.

The interplay of quaternary ammonium lipid structure and protein corona on lung-specific mRNA delivery by selective organ targeting (SORT) nanoparticles

Messenger RNA (mRNA) can treat genetic disease using protein replacement or genome editing approaches but requires a suitable carrier to circumnavigate biological barriers and access the desired cell type within the target organ. Lipid nanoparticles (LNPs) are widely used in the clinic for mRNA delivery yet are limited in their applications due to significant hepatic accumulation because of the formation of a protein corona enriched in apolipoprotein E (ApoE). Our lab developed selective organ targeting (SORT) LNPs that incorporate a supplementary component, termed a SORT molecule, for tissue-specific mRNA delivery to the liver, spleen, and lungs of mice. Mechanistic work revealed that the biophysical class of SORT molecule added to the LNP forms a distinct protein corona that helps determine where in the body mRNA is delivered. To better understand which plasma proteins could drive tissue-specific mRNA delivery, we characterized a panel of quaternary ammonium lipids as SORT molecules to assess how chemical structure affects the organ-targeting outcomes and protein corona of lung-targeting SORT LNPs. We discovered that variations in the chemical structure of both the lipid alkyl tail and headgroup impact the potency and specificity of mRNA delivery to the lungs. Furthermore, changes to the chemical structure alter the quantities and identities of protein corona constituents in a manner that correlates with organ-targeting outcomes, with certain proteins appearing to promote lung targeting whereas others reduce delivery to off-target organs. These findings unveil a nuanced relationship between LNP chemistry and endogenous targeting, where the ensemble of proteins associated with an LNP can play various roles in determining the tissue-specificity of mRNA delivery, providing further design criteria for optimization of clinically-relevant nanoparticles for extrahepatic delivery of genetic payloads.

Endometrial Cancer-Adjacent Tissues Express Higher Levels of Cancer-Promoting Genes than the Matched Tumors

Molecular alterations in tumor-adjacent tissues have recently been recognized in some types of cancer. This phenomenon has not been studied in endometrial cancer. We aimed to analyze the expression of genes associated with cancer progression and metabolism in primary endometrial cancer samples and the matched tumor-adjacent tissues and in the samples of endometria from cancer-free patients with uterine leiomyomas. Paired samples of tumor-adjacent tissues and primary tumors from 49 patients with endometrial cancer (EC), samples of endometrium from 25 patients with leiomyomas of the uterus, and 4 endometrial cancer cell lines were examined by the RT-qPCR, for MYC, NR5A2, CXCR2, HMGA2, LIN28A, OCT4A, OCT4B, OCT4B1, TWIST1, STK11, SNAI1, and miR-205-5p expression. The expression levels of MYC, NR5A2, SNAI1, TWIST1, and STK11 were significantly higher in tumor-adjacent tissues than in the matched EC samples, and this difference was not influenced by the content of cancer cells in cancer-adjacent tissues. The expression of MYC, NR5A2, and SNAI1 was also higher in EC-adjacent tissues than in samples from cancer-free patients. In addition, the expression of MYC and CXCR2 in the tumor related to non-endometrioid adenocarcinoma and reduced the risk of recurrence, respectively, and higher NR5A2 expression in tumor-adjacent tissue increased the risk of death. In conclusion, tissues proximal to EC present higher levels of some cancer-promoting genes than the matched tumors. Malignant tumor-adjacent tissues carry a diagnostic potential and emerge as new promising target of anticancer therapy.

Identification of Early Warning Signals at the Critical Transition Point of Colorectal Cancer Based on Dynamic Network Analysis

Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. Due to the lack of early diagnosis methods and warning signals of CRC and its strong heterogeneity, the determination of accurate treatments for CRC and the identification of specific early warning signals are still urgent problems for researchers. In this study, the expression profiles of cancer tissues and the expression profiles of tumor-adjacent tissues in 28 CRC patients were combined into a human protein–protein interaction (PPI) network to construct a specific network for each patient. A network propagation method was used to obtain a mutant giant cluster (GC) containing more than 90% of the mutation information of one patient. Next, mutation selection rules were applied to the GC to mine the mutation sequence of driver genes in each CRC patient. The mutation sequences from patients with the same type CRC were integrated to obtain the mutation sequences of driver genes of different types of CRC, which provide a reference for the diagnosis of clinical CRC disease progression. Finally, dynamic network analysis was used to mine dynamic network biomarkers (DNBs) in CRC patients. These DNBs were verified by clinical staging data to identify the critical transition point between the pre-disease state and the disease state in tumor progression. Twelve known drug targets were found in the DNBs, and 6 of them have been used as targets for anticancer drugs for clinical treatment. This study provides important information for the prognosis, diagnosis and treatment of CRC, especially for pre-emptive treatments. It is of great significance for reducing the incidence and mortality of CRC.

Non-Coding RNAs as Regulators and Markers for Targeting of Breast Cancer and Cancer Stem Cells

Breast cancer is regarded as a heterogeneous and complicated disease that remains the prime focus in the domain of public health concern. Next-generation sequencing technologies provided a new perspective dimension to non-coding RNAs, which were initially considered to be transcriptional noise or a product generated from erroneous transcription. Even though understanding of biological and molecular functions of noncoding RNA remains enigmatic, researchers have established the pivotal role of these RNAs in governing a plethora of biological phenomena that includes cancer-associated cellular processes such as proliferation, invasion, migration, apoptosis, and stemness. In addition to this, the transmission of microRNAs and long non-coding RNAs was identified as a source of communication to breast cancer cells either locally or systemically. The present review provides in-depth information with an aim at discovering the fundamental potential of non-coding RNAs, by providing knowledge of biogenesis and functional roles of micro RNA and long non-coding RNAs in breast cancer and breast cancer stem cells, as either oncogenic drivers or tumor suppressors. Furthermore, non-coding RNAs and their potential role as diagnostic and therapeutic moieties have also been summarized.

Role of the Microenvironment in Regulating Normal and Cancer Stem Cell Activity: Implications for Breast Cancer Progression and Therapy Response

The epithelial cells in an adult woman’s breast tissue are continuously replaced throughout their reproductive life during pregnancy and estrus cycles. Such extensive epithelial cell turnover is governed by the primitive mammary stem cells (MaSCs) that proliferate and differentiate into bipotential and lineage-restricted progenitors that ultimately generate the mature breast epithelial cells. These cellular processes are orchestrated by tightly-regulated paracrine signals and crosstalk between breast epithelial cells and their tissue microenvironment. However, current evidence suggests that alterations to the communication between MaSCs, epithelial progenitors and their microenvironment plays an important role in breast carcinogenesis. In this article, we review the current knowledge regarding the role of the breast tissue microenvironment in regulating the special functions of normal and cancer stem cells. Understanding the crosstalk between MaSCs and their microenvironment will provide new insights into how an altered breast tissue microenvironment could contribute to breast cancer development, progression and therapy response and the implications of this for the development of novel therapeutic strategies to target cancer stem cells.

Paracrine Crosstalk between Fibroblasts and ER+ Breast Cancer Cells Creates an IL1β-Enriched Niche that Promotes Tumor Growth

Breast cancer-induced activated fibroblasts support tumor progression. However, the role of normal fibroblasts in tumor progression remains controversial. In this study, we used modified patient-derived organoid cultures and demonstrate that constitutively secreted cytokines from normal breast fibroblasts initiate a paracrine signaling mechanism with estrogen receptor-positive (ER⁺) breast cancer cells, which results in the creation of an interleukin (IL)-1β-enriched microenvironment. We found that this paracrine signaling mechanism is shared between normal and activated fibroblasts. Interestingly, we observed that in reconstructed tumor microenvironment containing autologous ER⁺ breast cancer cells, activated fibroblasts, and immune cells, tamoxifen is more effective in reducing tumor cell proliferation when this paracrine signaling is blocked. Our findings then suggest that ER⁺ tumor cells could create a growth-promoting environment without activating stromal fibroblasts and that in breast-conserving surgeries, normal fibroblasts could be a significant modulator of tumor recurrence by enhancing the proliferation of residual breast cancer cells in the tumor-adjacent breast tissue.

•

Normal fibroblast-cancer cell interaction promotes tumor progression

•

Paracrine signaling common to normal and activated fibroblasts promotes drug resistance

•

Fibroblast-secreted factors create an IL1β-enriched niche for ER⁺ breast cancer cell growth

Transcriptional regulation of normal human mammary cell heterogeneity and its perturbation in breast cancer

The mammary gland in adult women consists of biologically distinct cell types that differ in their surface phenotypes. Isolation and molecular characterization of these subpopulations of mammary cells have provided extensive insights into their different transcriptional programs and regulation. This information is now serving as a baseline for interpreting the heterogeneous features of human breast cancers. Examination of breast cancer mutational profiles further indicates that most have undergone a complex evolutionary process even before being detected. The consequent intra-tumoral as well as inter-tumoral heterogeneity of these cancers thus poses major challenges to deriving information from early and hence likely pervasive changes in potential therapeutic interest. Recently described reproducible and efficient methods for generating human breast cancers de novo in immunodeficient mice transplanted with genetically altered primary cells now offer a promising alternative to investigate initial stages of human breast cancer development. In this review, we summarize current knowledge about key transcriptional regulatory processes operative in these partially characterized subpopulations of normal human mammary cells and effects of disrupting these processes in experimentally produced human breast cancers.

A robust cell culture system for large scale feeder cell-free expansion of human breast epithelial progenitors

Background

Normal human breast epithelial cells are maintained by the proliferation and differentiation of different human breast epithelial progenitors (HBEPs). However, these progenitor subsets can only be obtained at low frequencies, limiting their further characterization. Recently, it was reported that HBEPs can be minimally expanded in Matrigel cocultures with stromal feeder cells. However, variability of generating healthy feeder cells significantly impacts the effective expansion of HBEPs.

Methods

Here, we report a robust feeder cell-free culture system for large-scale expansion of HBEPs in two-dimensional cultures.

Results

Using this cell culture system HBEPs can be exponentially expanded as bulk cultures. Moreover, purified HBEP subtypes can also be separately expanded using our cell culture system. The expanded HBEPs retain their undifferentiated phenotype and form distinct epithelial colonies in colony forming cell assays.

Conclusions

The availability of a culture system enabling the large-scale expansion of HBEPs facilitates their application to screening platforms and other cell-based assays.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0994-y) contains supplementary material, which is available to authorized users.