Tumors are a heterogeneous group of cells from diverse organs, ranging from stem cells and endothelial cells, to a wide range of immune cells. The plethora of secretory signals from cancer cells have numerous effects that help promote tumor growth and progression, while also perturbing the immunologic surveillance of developing tumors. Cancerous cells express their own profile of cytokines and chemokines that facilitate inflammation, cell growth, and recruitment of new blood vessels, while also recruiting accessory cell populations for their survival and immunologic avoidance. Collectively, these local changes promote the developing tumor microenvironment (TME).
Interrogation of the tumor environment’s niche of cell signals, growth factors, and cytokines, as well as the TME recruitment of accessory cell populations and their cytokines, requires a global view of all these factors together. While a piecemeal approach may prove effective if the hypothesis is sufficiently narrow, a broad view of cancer will be needed for biomarker discovery and diagnostics moving forward. Multiplexed immunoassays remain the best and most complete means to study the proteomic changes within the TME, as they afford the most global view of protein changes from numerous and disparate cell populations. RayBiotech’s antibody array platforms therefore represent powerful tools for the identification of new cancer biomarkers, either from the local TME, or from the cancer cells themselves.
Th1 lymphocytes and M1 macrophages are the primary sources of pro-inflammatory cytokines that promote cancer immunosurveillance and cytotoxicity. Their interactions are mutually reinforcing: Secretion IFN-γ by Th1 cells results in the recruitment and maintenance of M1, while IL-12 produced by M1 macrophages recruits, activates and maintains Th1cells. Secretion of MIG/CXCL9 and IP-10/CXCL10 also promotes the recruitment of Th1 cells and CTLs and inhibits angiogenesis. IL-1α, IL-1β and IL-6 form an autocrine feedback loop by stimulation of myeloid differentiation primary response gene 88 (MyD88)-mediated activation of NF-κB signaling. TNF-α, also released by the activation of NF-κB signaling, which activates APC functions of DCs and the recruitment and cytotoxic activation ofM1 macrophages, effector CD4+ T cells, and CD8+ cells, as well as the recruitment of NK cells.
Th2 lymphocytes, M2 macrophages and MDSCs mutually reinforce the proliferation and phenotypes of one another, as well as maintaining tumor-promoting inflammation and angiogenesis. These cells, along with T regulatory lymphocytes (TREGs) suppress the activity and proliferation of tumor-suppressing cells, including Th1, M1 and cytotoxic T cells and NK cells. It should be noted that M1 &M2 macrophages can interconvert, but these phenotypes are stable as the M1 and M2 expression profiles reinforce their own macrophage phenotypes, while suppressing the other. Similarly, Th1 & Th2 lymphocytes, as well as TREG & Th17 lymphocytes tend to self-reinforce their own activation profiles and inhibit the other.
Normal cells may become nascent tumors by evading tumor suppression after carcinogenic mutation and/or apoptosis that would normally result from gross chromosomal changes. Pro-inflammatory and pro-angiogenic factors can help to establish blood supply for the growing nascent tumor. Activation of the adaptive or native immune response can eliminate the nascent tumor, the tumor may remain in equilibrium as an occult tumor, or the tumor may escape immunosurveillance to create a viable tumor-supportive microenvironment. Innate and adaptive immune responses may still work to eliminate the tumor via immunosurveillance. Tumors may also metastasize to move to another location; this may be an additional mechanism of avoiding immunosurveillance by evacuation of the “hostile” TME. Green color denotes processes potentially leading to tumor eradication, while red color means promoting tumor escape and progression.
In the TME, a positive feedback loop of cytokine signals that proceeds as follows: First, TGF-β, COX2, PGE2, Th2- associated inflammatory factors and proangiogenic proteins are secreted by cancer cells, CAFs and other cell types in the nascent tumor recruit Th2 lymphocytes, M2 macrophages (TAMs) andN2 neutrophils (TANs). Then, Th2 lymphocytes, TAMs and TANs secrete additional inflammatory and proangiogenic proteins that suppress maturation of DCs and proliferation and activation of cytotoxic cells. As a result, antigen presentation and cytotoxic activities plummet, practically eliminating immunosurveillance in the tumor milieu. Additionally, B cells proliferate, but are not activated, turning them into tumor-promoting BREGs. M2macrophages recruit MDSCs to the TME, further reinforcing the positive feedback loop of Th2, M2, and N2 proliferation and activation, resulting in substantial increases in tumor-promoting inflammation and concomitant angiogenesis.
Pancreatic cancer is one of the most deadly types of cancers because many patients are diagnosed at later stages and the cancer often acquires early chemotherapy resistance. In the study by Debernardi et al., previously identified candidate diagnostic biomarkers of pancreatic cancer (LYVE1, REG1B, TFF1) were validated using retrospectively-collected urine samples from healthy controls, patients with benign hepatobiliary diseases, and pancreatic cancer patients. The objective of Takahashi et al.'s study was to identify a blood-based protein biomarker to identify when chemotherapy resistance develops. Their data show that serological VCAM-1 may be a potential therapeutic target, as well as a prognosis marker, in patients with advanced disease.
Debernardi S, et al. A combination of urinary biomarker panel and PancRISK score for earlier detection of pancreatic cancer: A case-control study. PLoS Med. (2020). [view publication]
RayBiotech Products: Sandwich ELISA (cat no. ELH-LYVE1, ELH-CA19-9)
Sample Type: Urine
Takahashi R., et al. Soluble VCAM-1 promotes gemcitabine resistance via macrophage infiltration and predicts therapeutic response in pancreatic cancer. Sci Rep (2020). [view publication]
RayBiotech Products: C-Series (custom)
Sample Type: Plasma
One hallmark of cancer cells is their ability to evade destruction by the immune system. To counteract this hallmark, a promising group of "immune checkpoint blockade" drugs that release inherent limitations on T cell effector function has emerged, yet the efficiencies of currently-approved drugs remain low. This study shows that a metal-free photothermal agent, black phosphorous nanosheets, can destroy tumor cells directly, stimulate the immune response to destroy tumor cells, and enhance the efficacy of immune checkpoint blockade drugs.
Xie Z, et al. Black phosphorus-based photothermal therapy with a CD47-mediated immune checkpoint blockade for enhanced cancer immunotherapy. Light Sci Appl. (2020). [view publication]
RayBiotech Products: Phosphorylation Array (cat no. AAH-MAPK-1)
Sample Type: Tissue lysate
Brain tumors progress, in part, due to dynamic interactions between the tumor cells and the extracellular matrix (ECM). However, the specific contributions of the ECM components toward tumor development and progression remain unknown. Sood et al. established a 3D bioengineered brain tumor system to study tumor growth and drug responses in different microenvironments across time with high resolution. Using the system with patient-derived brain tumor cells, they show that different tumor types secrete distinct levels of secreted proteins (e.g., MMPs, TIMPs) within the same ECM microenvironment. Their 3D ECM system can help unravel the complex cell-ECM microenvironment of brain malignancies.
Sood D, et al. 3D extracellular matrix microenvironment in bioengineered tissue models of primary pediatric and adult brain tumors. Nat Commun (2019) [view publication]
RayBiotech Products: Quantibody (cat no. QAH-MMP-1), C-Series (cat no. AAH-CYT-5)
Sample Type: Conditioned medium
Dysregulated protein folding occurs in many cancer types, leading to autophagy-mediated cell survival. Here, the authors show that MUL1, a ubiquitin ligase activator, causes the ubiquitination of HSPA5/GRP78/BiP, a heat shock protein that regulates the homeostatic protein folding response. HSPA5 ubiquitination leads to a cell death via apoptosis in head and neck cancer cells. These data identify a new therapeutic target, MUL1-HSPA5, for treating head and neck cancer.
Kim S., et al. HSPA5 negatively regulates lysosomal activity through ubiquitination of MUL1 in head and neck cancer. Autophagy (2018). [view publication]
RayBiotech Products: Transcription Factor Sandwich ELISA (cat no. TFEH-TFEB-1)
Sample Type: Cell lysate
Most breast cancers respond poorly to immunotherapy. Using the PyMT luminal tumor mouse model inhibition of RANK signaling led to improved immunotherapy efficacy, immune activation, and increased immune infiltration. Moreover, the data show the potential therapeutic benefits of using RANK ligand (RL) inhibitors, including the monoclonal antibody "denosumab" that binds to RL and inhibits RANK, in luminal breast cancers with poor immunogenicity.
Gómez-Aleza C, et al. Inhibition of RANK signaling in breast cancer induces an anti-tumor immune response orchestrated by CD8+ T cells. Nat Commun (2020). [view publication]
RayBiotech Products: C-Series (cat no. AAM-CYT-1000)
Sample Type: Conditioned medium