Combined evaluation of NGF and p75NGFR expression is a biomarker for predicting prognosis in human invasive ductal breast carcinoma

Regulating Tumorigenicity and Cancer Metastasis through TRKA Signaling

Tropomyosin receptor kinase (TRK) A, TRKA, is a specific binding receptor of nerve growth factor (NGF), which plays an essential role in the occurrence and progression of human cancers. TRKA overexpression has been proven to be a powerful carcinogenic driver and has been verified in many tumors. The TRKA receptor kinase domain is over-activated in an NGF-dependent manner, accompanied by activation of downstream signal pathways, such as RAS-MAPK, PI3K-AKT, JAK2-STAT3 pathway, PLC γ pathway, and Hippo pathway, which participate in tumor cell proliferation, invasion, epithelial-mesenchymal transition (EMT), perineural invasion (PNI), drug resistance, and cancer pain. In addition, chimeric oncogenes produced by the fusion of NTRK1 and other genes are also the direct cause of tumorigenesis and cancer development. The newly developed TRK inhibitors can improve symptoms and tumor regression in cancer patients with overexpression of TRKA or NTRK1 fusion gene. With the emergence of drug resistance, next generation of TRK inhibitors can still maintain strong clinical efficacy in the case of TRK kinase domain mutations, and these inhibitors are in clinical trials. This review summarizes the characteristics and research progress of TRKA, focusing on the regulatory role of the TRKA signal pathway in different tumors. In addition, we have summarized the clinical significance of TRKA and the TRK inhibitors. This review may provide a new reference for the study of the mechanism of TRKA in different tumors, and also provide a new perspective for the in-depth understanding of the role of TRKA as a biomarker and therapeutic target in human cancer.

Expression and Signaling Pathways of Nerve Growth Factor (NGF) and Pro-NGF in Breast Cancer: A Systematic Review

Breast cancer represents the most common type of cancer and is the leading cause of death due to cancer among women. Thus, the prevention and early diagnosis of breast cancer is of primary urgency, as well as the development of new treatments able to improve its prognosis. Nerve Growth Factor (NGF) is a neurotrophic factor involved in the regulation of neuronal functions through the binding of the Tropomyosin receptor kinase A (TrkA) and the Nerve Growth Factor receptor or Pan-Neurotrophin Receptor 75 (NGFR/p75NTR). In addition, its precursor (pro-NGF) can extert biological activity by forming a trimeric complex with NGFR/p75NTR and sortilin, or by binding to TrkA receptors with low affinity. Several examples of in vitro and in vivo evidence show that NGF is both synthesized and released by breast cancer cells, and has mitogen, antiapoptotic and angiogenic effects on these cells through the activation of different signaling cascades that involve TrkA and NGFR/p75NTR receptors. Conversely, pro-NGF signaling has been related to breast cancer invasion and metastasis. Other studies suggested that NGF and its receptors could represent a good diagnostic and prognostic tool, as well as promising therapeutic targets for breast cancer. In this paper, we comprehensively summarize and systematically review the current experimental evidence on this topic. INPLASY ID: INPLASY2022100017.

Co-expression of NGF and PD-L1 on tumor-associated immune cells in the microenvironment of Merkel cell carcinoma

PURPOSE

Merkel cell carcinoma (MCC) is a malignant neuroendocrine skin tumor with known viral association. The microenvironment and its interaction with the tumor via the programmed cell death protein 1 (PD-1) pathway are crucial for response to anti-PD-1/anti-PD-L1 treatments. However, not all patients respond, which is suggestive of additional mechanisms for tumor growth and/or persistence. We previously detected tropomyosin receptor kinase A (TrkA) expression on MCC tumor cells and, therefore, gained interest in the expression of its ligand nerve growth factor (NGF).

METHODS

Thirty-nine patients from our department were studied for immunohistochemical NGF, PD-1, and PD-L1 expression and clinico-pathological correlation.

RESULTS

PD-L1 was expressed on the tumor cells in 42%. In 95%, PD-L1 expression was also found on CD68+ spindle cells at the tumor border, which co-expressed NGF in 71%. 66% contained PD-1+ tumor infiltrating lymphocytes. PD-1, PD-L1, and NGF expression seems to correlate with a worse outcome.

CONCLUSIONS

The present study shows that PD-L1 and NGF are co-expressed on spindle cells in the microenvironment. The expression of NGF might be a link of the microenvironment to the TrkA-positive tumor cells. Whether this mechanism is critical for tumor growth and lack of response to anti-PD-1/L1 treatment has to be investigated in further studies.

Individual and co-expression patterns of nerve growth factor and heme oxygenase-1 predict shorter survival of gastric carcinoma patients

BACKGROUND

Nerve growth factor (NGF) is a neurotrophic factor which regulates cell development and proliferation. Recently, it has been suggested that NGF induces heme oxygenase-1 (HO1) expression, and that both NGF and HO1 are involved in the progression of malignant human tumors. However, exact roles of NGF and HO1 in tumorigenesis remain controversial. Therefore, we investigated the expression and correlation of NGF and HO1 in human gastric carcinoma tissues.

METHODS

We examined immunohistochemical expression of NGF and HO1 in 167 gastric carcinomas and compared with various prognostic clinicopathological factors.

RESULTS

The expression of NGF and HO1 was positive in 40% (67/167) and 51% (85/167) of cases, respectively, and their expression was significantly correlated with each other (p < 0.001). Individual expression patterns of NGF and HO1, and co-expression pattern of these two molecules were significantly associated with shorter survival by univariate analysis. HO1 expression (overall survival; p < 0.001, relapse-free survival; p = 0.002) and co-expression pattern of NGF and HO1 (overall survival; p = 0.002, relapse-free survival; p = 0.003) were independent poor prognostic indicators of gastric carcinoma patients by multivariate analysis.

CONCLUSIONS

These results demonstrate that the individual and co-expression patterns of NGF and HO1 might be used as prognostic indicators for gastric carcinoma patients.

Mechanism of cancer pain

Ongoing and breakthrough pain is a primary concern for the cancer patient. Although the etiology of cancer pain remains unclear, animal models of cancer pain have allowed investigators to unravel some of the cancer-induced neuropathologic processes that occur in the region of tumor growth and in the dorsal horn of the spinal cord. Within the cancer microenvironment, cancer and immune cells produce and secrete mediators that activate and sensitize primary afferent nociceptors. Pursuant to these peripheral changes, nociceptive secondary neurons in spinal cord exhibit increased spontaneous activity and enhanced responsiveness to three modes of noxious stimulation: heat, cold, and mechanical stimuli. As our understanding of the peripheral and central mechanisms that underlie cancer pain improves, targeted analgesics for the cancer patient will likely follow.

Significance of nerve growth factor overexpression and its autocrine loop in oesophageal squamous cell carcinoma

Nerve growth factor (NGF) is overexpressed not only in nervous system, but also in several types of cancers. However, the role of NGF in oesophageal squamous cell carcinoma (OESCC) remains unclear. Here, we show the first evidence of NGF-TrkA autocrine loop and clinical significance of NGF overexpression in OESCC. Immunohistochemical study of 109 OESCC specimens revealed that NGF overexpression, found in 63 out of 109 patients (57.8%), was associated with lymph node metastasis, distant metastasis, higher TNM stage, poorer tumour differentiation, and poorer survival. NGF overexpression was also associated with strong expression of TrkA and negative expression of low-affinity neurotrophin receptor (p75NTR). Semiquantitative reverse transcription–polymerase chain reaction (RT–PCR) of 19 surgical specimens showed upregulation of NGF mRNA in 17 out of 19 (89%) patients. All five OESCC cell lines tested in vitro secreted detectable NGF in enzyme-linked immunosorbent assay, and expressed TrkA and p75NTR on RT–PCR and Western blot. The motility of HSA/c, one of the OESCC cell lines overexpressing NGF, was significantly decreased by either neutralising anti-NGF antibody, an inhibitor of TrkA, or NGF-small interfering RNA in transwell migration assay. Our findings suggest that NGF is of potential interest not only as a prognostic factor, but also as a novel therapeutic target in OESCC.