Article: Nerve growth factor and its receptor tyrosine kinase TrkA are overexpressed in cervical squamous cell carcinoma

Annals of Oncology 30: 1071–1079, 2019
doi:10.1093/annonc/mdz132
Published online 15 May 2019

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7354692/

Authors: Sam Faulkner, ^{1 , 2} Nathan Griffin, ^{1 , 2} Christopher W. Rowe, ^{2 , 3} Phillip Jobling, ^{1 , 2} Janine M. Lombard, ^{3 , 4} Sonia M. Oliveira, ² Marjorie M. Walker, ^{2 , 3} and Hubert Hondermarck  ^{1 , 2}

 Affiliations:

1. School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan NSW, Australia,
2. Hunter Medical Research Institute, University of Newcastle, New Lambton NSW, Australia,
3. School of Medicine and Public Health, Faculty of Health and Medicine, University of Newcastle, Callaghan NSW, Australia,
4. Department of Medical Oncology, Calvary Mater Newcastle, Waratah NSW, Australia,

This research was supported by the University of Newcastle (Australia), the Hunter Medical Research Institute (HMRI), and the Hunter Cancer Research Alliance (HCRA).

 Funders:

Hunter Medical Research Institute (HMRI), Australia; Grant/Award Number: G1501579.

Aim:

Cervical cancer in females are divided into 75% squamous cell carcinoma (SCC) and 25% adenocarcinoma/adenosquamous carcinoma (AC/ASC), which represents 7% of all female cancers. There is need for advancement in diagnostic, prognostic, and therapeutics as 10% of 50% worldwide cases in developing countries are diagnosed at late stages of the disease.

Nerve growth factor (NGF) has been shown to play role in cancer progression and perineural invasion. In cervical cancer the expression of NGF is yet to be defined, this study aims to define the NGFs including its precursor proNGF, its receptors TrkA (tyrosine kinase receptor), p75NTR  (neurotrophin receptor )and sortilin (pro-neurotrophin receptor).

Terminology:

• Squamous cell carcinomas (SCC) – is cancer in the flat, thin cells that cover the outer surface of the cervix called Squamous cells .
• Adenocarcinomas (AC)- cancer in column shaped Glandular cells that cover the inner surface of the cervix
• HeLa cells – human cell line derived from cervical cancer
• H-score – percentage of cells multiplication with staining intensity ordinal value

Method:

Cervical tissue samples High-density tissue microarrays

• 294 cases of cervical carcinomas from US Biomax Inc.
  1. 257 SCC
  2. 30 AC
  3. 7 unspecified histopathological subtypes

Protocol approved by the Human Research Ethics Committee of the University of Newcastle, Australia (HREC reference: H-2012-0063;March 26, 2019)

• Analysis information avail from the samples via immunohistochemistry and digital quantification

1. Patient age
2. histopathological diagnosis
3. Classification of malignant tumors (TNM) with stage, and grade.

Statistical analysis of immunohistochemistry quantification was done by the following methods

• H-score distributions were studied.
• Two-sided alpha of 0.05 was used to analysis the difference in neurotrophin and receptor expression between benign and malignant samples.

The impact of TrkA signaling in cervical cancer

• HELA cells with the Trk inhibitor GNF-5837 were assessed for drug sensitivity, impact on viability and signalling.

Results:

Studying associations between NGF, proNGF, TrkA, p75NTR and sortilin expression with clinicopathological parameters in SCC, identified association of NGF and proNGF expression with higher grade classification (abnormally of the cancer cell appearance). Similarly, association of p75NTR protein expression increase with higher grade classification in SCC. For sortilin the expression was seen to be high in both AC and SCC. Overall expression of proNGF, NGF, TrkA, p75NTR, and sortilin are higher in cervical cancer vs normal cervical tissues.

Analysing expression of TrkA in cervical cancers and normal cervical tissue uncovered that high TrkA was expressed in all SCC cells, which was further confirmed by digital quantification of low TrkA immunoreactivity in normal cervical tissue and AC. Furthermore, nerve infiltration investigation found TrkA expression was found in large nerves within the tumor microenvironment. It was also reported viability reduction to in HELA cells with the Trk inhibitor GNF-5837 indicating that of targeting TrkA signalling in could be beneficial.

Conclusion:

The overexpression of NGF and TrkA in SCC is a discovery that warrants future investigation and is an opportunity for targeted therapy. Currently Trk pharmacological inhibitors are being trialled for other cancers. This study demonstrats that such inhibitors could be targeted at cervical SCC.

Relevance:

The study has revealed the clinicopathological importance of NGF and proNGF profiles in cervical cancer.

The use of human samples, digital quantification and vitro experiments is worth highlighting as a research approach. The study was able to draw parallels with already existing trials and identify the cervical SCC as target.

HRA Comment:

According to Australian cancer council each year about 850 women are diagnosed with cervical cancer in Australia. The early-stage detection results in most positive prognosis and avoid extreme circumstances around fertility. This study welcomes further investigations in prognosis and treatment.

Although the study does not directly use any animals it was noted antibodies with animal hosts were purchased and utilised.