Introduction: Tumor is a heterogeneous mass of malignant cells co-existing with non-malignant cells. This co-existence evolves from the initial developmental stages of the tumor and is one of the hallmarks of cancer providing a protumorigenic niche known as tumor microenvironment (TME). Proliferation, invasiveness, metastatic potential and maintenance of stemness through cross-talk between tumors and its stroma forms the basis of TME.
Areas covered: The article highlights the developmental phases of a tumor from dysplasia to the formation of clinically detectable tumors. The authors discuss the mechanistic stages involved in the formation of TME and its contribution in tumor outgrowth and chemoresistance. The authors have reviewed various approaches for targeting TME and its hallmarks along with their advantages and pitfalls. The authors also highlight cancer stem cells (CSCs) that are resistant to chemotherapeutics and thus a primary reason for tumor recurrence thereby, posing a challenge for the oncologists.
Expert opinion: Recent understanding of the cellular and molecular mechanisms involved in acquired chemoresistance has enabled scientists to target the tumor niche and TME and modulate and/or disrupt this communication leading to the transformation from a tumor-supportive niche environment to a tumor-non-supporting environment and give synergistic results towards an effective management of cancer. 相似文献
Aim: To investigate the effects of plumbagin, a naphthoquinone derived from the medicinal plant Plumbago zeylanica, on human breast cancer cell growth and the cancer cell-induced osteolysis in the bone microenvironment of mice. Methods: Human breast cancer cell subline MDA-MB-231SA with the ability to spread and grow in the bone was tested. The cell proliferation was determined using the CCK-8 assay. Apoptosis was detected with Annexin V/PI double-labeled flow cytometry. Red fluorescent protein-labeled MDA-MB-231SArfp cells were injected into the right tibia of female BALB/c-nu/nu mice. Three days after the inoculation, the mice were injected with plumbagin (2, 4, or 6 mg/kg, ip) 5 times per week for 7 weeks. The growth of the tumor cells was monitored using an in vivo imaging system. After the mice were sacrificed, the hind limbs were removed for radiographic and histological analyses.
Results: Plumbagin (2.5–20 μmol/L) concentration-dependently inhibited the cell viability and induced apoptosis of MDA-MB-231SA cells in vitro (the IC50 value of inhibition of cell viability was 14.7 μmol/L). Administration of plumbagin to breast cancer bearing mice delayed the tumor growth by 2–3 weeks and reduced the tumor volume by 44%–74%. The in vivo imaging study showed that plumbagin dose-dependently inhibited MDA-MB-231SArfp cell growth in bone microenvironment. Furthermore, X-ray images and micro-CT study demonstrated that plumbagin reduced bone erosion area and prevented a decrease in bone tissue volume. Histological studies showed that plumbagin dose-dependently inhibited the breast cancer cell growth, enhanced the cell apoptosis and reduced the number of TRAcP-positive osteoclasts.
Conclusion: Plumbagin inhibits the cell growth and induces apoptosis in human breast cancer cells in mice bone microenvironment, leading to significant reduction in osteolytic lesions caused by the tumor cells. 相似文献
Clinical studies have shown that hyperbaric oxygen therapy improves motor function in patients with spinal cord injury. In the present study, we explored the mechanisms associated with the recovery of neurological function after hyperbaric oxygen therapy in a rat model of spinal cord injury. We established an acute spinal cord injury model using a modification of the free-falling object method, and treated the animals with oxygen at 0.2 MPa for 45 minutes, 4 hours after injury. The treatment was administered four times per day, for 3 days. Compared with model rats that did not receive the treatment, rats exposed to hyperbaric oxygen had fewer apoptotic cells in spinal cord tissue, lower expression levels of aquaporin 4/9 mRNA and protein, and more NF-200 positive nerve fibers. Furthermore, they had smaller spinal cord cavities, rapid recovery of somatosensory and motor evoked potentials, and notably better recovery of hindlimb motor function than model rats. Our findings indicate that hyperbaric oxygen therapy reduces apoptosis, downregulates aquaporin 4/9 mRNA and protein expression in injured spinal cord tissue, improves the local microenvironment for nerve regeneration, and protects and repairs the spinal cord after injury. 相似文献
Glioblastomas (GBMs) diffusely infiltrate the brain, making complete removal by surgical resection impossible. The mixture of neoplastic and nonneoplastic cells that remain after surgery form the biological context for adjuvant therapeutic intervention and recurrence. We performed RNA-sequencing (RNA-seq) and histological analysis on radiographically guided biopsies taken from different regions of GBM and showed that the tissue contained within the contrast-enhancing (CE) core of tumors have different cellular and molecular compositions compared with tissue from the nonenhancing (NE) margins of tumors. Comparisons with the The Cancer Genome Atlas dataset showed that the samples from CE regions resembled the proneural, classical, or mesenchymal subtypes of GBM, whereas the samples from the NE regions predominantly resembled the neural subtype. Computational deconvolution of the RNA-seq data revealed that contributions from nonneoplastic brain cells significantly influence the expression pattern in the NE samples. Gene ontology analysis showed that the cell type-specific expression patterns were functionally distinct and highly enriched in genes associated with the corresponding cell phenotypes. Comparing the RNA-seq data from the GBM samples to that of nonneoplastic brain revealed that the differentially expressed genes are distributed across multiple cell types. Notably, the patterns of cell type-specific alterations varied between the different GBM subtypes: the NE regions of proneural tumors were enriched in oligodendrocyte progenitor genes, whereas the NE regions of mesenchymal GBM were enriched in astrocytic and microglial genes. These subtype-specific patterns provide new insights into molecular and cellular composition of the infiltrative margins of GBM.Glioma cells diffusely infiltrate the brain and intermingle with neural cells in the surrounding brain tissue, resulting in a complex mixture that includes variable proportions of glioma cells, neurons, and various lineages of reactive or recruited glia. At the infiltrative margins of glioblastoma (GBM), the nonneoplastic brain cells can far outnumber the glioma cells and, therefore, will have a significant effect on the molecular features of the tissue. Expression profiling and whole genome sequencing from hundreds of GBM specimens by The Cancer Genome Atlas (TCGA) has revealed a broad spectrum of genetic alterations and discrete expression signatures or subtypes that stratify the majority of patients (1, 2). These studies analyzed tumor samples that were removed during surgery, but were not radiographically localized and, therefore, do not address the question of how the molecular signature may vary across different regions of a tumor. Recent studies have sampled multiple regions within a GBM and shown that more than one molecular subtype can coexist within a single tumor (3). However, the effect of varying cellular composition on GBM subtype, particularly the contribution of nonneoplastic cells, has not been addressed.GBM typically appears as a contrast-enhancing mass, which represents the highly cellular core of the tumor with vascular proliferation and blood–brain barrier breakdown. This contrast-enhancing (CE) region is typically surrounded by a diffuse, nonenhancing (NE) region of abnormal T2/FLAIR signal, which represents edematous brain tissue with varying numbers of infiltrating glioma cells. The primary treatment of GBM is surgical resection, during which the surgeon removes as much of the CE mass as possible. Thus, molecular and genetic profiling of GBM, including the TCGA effort, has predominantly used samples from the CE regions of tumor. However, it is the NE regions of glioma that are left behind after surgery, which neurooncologists must treat and which inevitably give rise to recurrence. Thus, there is immense prognostic and therapeutic significance to understanding the cellular and molecular features of the NE regions of tumor, yet often these areas are not resected and, therefore, have not been directly studied.There are two major obstacles to this goal. The first is the surgical challenge of radiographically localized sampling of the NE tumor margins. The second is the issue of the complex cellular composition that characterizes these regions of diffuse infiltration. In this study, we have addressed both challenges, and associated distinct molecular and cellular features of the NE regions of GBM with the molecular subtype, as defined by the resected CE regions of the tumor. 相似文献
Recent clinical success has underscored the potential for immunotherapy based on the adoptive cell transfer (ACT) of engineered T lymphocytes to mediate dramatic, potent, and durable clinical responses. This success has led to the broader evaluation of engineered T-lymphocyte-based adoptive cell therapy to treat a broad range of malignancies. In this review, we summarize concepts, successes, and challenges for the broader development of this promising field, focusing principally on lessons gleaned from immunological principles and clinical thought. We present ACT in the context of integrating T-cell and tumor biology and the broader systemic immune response. 相似文献
Diffuse large B-cell lymphoma (DLBCL) is the most common type of malignant lymphoma with biologically and clinically heterogeneous features. Recently, the tumor microenvironment of this disease has been recognized as an important biological aspect of tumor development and therapeutic targets. Recurrent genetic alterations play significant roles in immune recognition of lymphoma cells. In particular, novel genetic alterations promoting phagocytosis were identified, suggesting a potential therapeutic strategy targeting the “don’t eat me” signal. 相似文献