Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2014 Feb 13:10:5.
doi: 10.1186/1744-9081-10-5.

IB4(+) and TRPV1(+) sensory neurons mediate pain but not proliferation in a mouse model of squamous cell carcinoma

Yi Ye, Sam S Bae, Chi T Viet, Scott Troob, Daniel Bernabé, Brian L Schmidt  1
Affiliations

IB4(+) and TRPV1(+) sensory neurons mediate pain but not proliferation in a mouse model of squamous cell carcinoma

Yi Ye et al. Behav Brain Funct. .

Abstract

Background: Cancer pain severely limits function and significantly reduces quality of life. Subtypes of sensory neurons involved in cancer pain and proliferation are not clear.

Methods: We produced a cancer model by inoculating human oral squamous cell carcinoma (SCC) cells into the hind paw of athymic mice. We quantified mechanical and thermal nociception using the paw withdrawal assays. Neurotoxins isolectin B4-saporin (IB4-SAP), or capsaicin was injected intrathecally to selectively ablate IB4(+) neurons or TRPV1(+) neurons, respectively. JNJ-17203212, a TRPV1 antagonist, was also injected intrathecally. TRPV1 protein expression in the spinal cord was quantified with western blot. Paw volume was measured by a plethysmometer and was used as an index for tumor size. Ki-67 immunostaining in mouse paw sections was performed to evaluate cancer proliferation in situ.

Results: We showed that mice with SCC exhibited both mechanical and thermal hypersensitivity. Selective ablation of IB4(+) neurons by IB4-SAP decreased mechanical allodynia in mice with SCC. Selective ablation of TRPV1(+) neurons by intrathecal capsaicin injection, or TRPV1 antagonism by JNJ-17203212 in the IB4-SAP treated mice completely reversed SCC-induced thermal hyperalgesia, without affecting mechanical allodynia. Furthermore, TRPV1 protein expression was increased in the spinal cord of SCC mice compared to normal mice. Neither removal of IB4(+) or TRPV1(+) neurons affected SCC proliferation.

Conclusions: We show in a mouse model that IB4(+) neurons play an important role in cancer-induced mechanical allodynia, while TRPV1 mediates cancer-induced thermal hyperalgesia. Characterization of the sensory fiber subtypes responsible for cancer pain could lead to the development of targeted therapeutics.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Nociceptive behavior in IB4-SAP and SAP treated SCC mice. A. Mechanical thresholds were decreased from baseline following SCC inoculation in both treatment groups (P < 0.001 for baseline vs. week 2 and week 4 in the IB4-SAP and SAP groups). IB4-SAP (N = 8) and SAP (N = 8) treated mice had similar mechanical thresholds at baseline and at post inoculation week 2. However, IB4-SAP significantly reduced SCC-induced mechanical allodynia compared to SAP treated mice at week 4 post inoculation (*, P < 0.05). While no difference in mechanical thresholds was found in IB4-SAP group between week 2 and week 4, mechanical thresholds were significantly reduced in SAP mice from week 2 to week 4 (#, P < 0.001). B. Thermal latency was decreased from baseline following SCC inoculation (P < 0.001 for baseline vs. week 2 and week 4 in the IB4-SAP and SAP groups). IB4-SAP and SAP treated mice had similar thermal latency at baseline and at week 2 post inoculation. IB4-SAP treatment significantly increased thermal hyperalgesia compared to SAP treated mice at week 4 post inoculation (*, P < 0.05).
Figure 2
Figure 2
Nociceptive behavior in IB4-SAP treated SCC mice injected with capsaicin and the TRPV1 antagonist (JNJ-17203212). Six mice were used in each group. All mice were treated with IB4-SAP 2 weeks before SCC inoculation. Capsaicin was injected intrathecally at week 3 post inoculation. JNJ-17203212 was injected intrathecally 30 min before the behavior measurement at week 5. A. No difference in mechanical thresholds was found among capsaicin, JNJ-17203212, or vehicle injected SCC mice throughout the observation time (5 weeks after SCC inoculation). All animals in the capsaicin, JNJ-17203212, and vehicle injected groups had reduced mechanical thresholds from baseline at week 2, week 4, and week 5 relative to baseline (P < 0.001 in all measurements). B. Capsaicin injection significantly reversed thermal hyperalgesia at weeks 4 and 5, one and two weeks after capsaicin injection, respectively (*, P < 0.05; capsaicin vs. vehicle or JNJ-17203212 at week 4; **, P < 0.01 capsaicin vs. vehicle at week 5). JNJ-17203212 injection also reversed thermal hyperalgesia at week 5 (**, P < 0.01, JNJ-17203212 vs. vehicle).
Figure 3
Figure 3
Spinal TRPV1 protein was increased in cancer mice. TRPV1 protein expression was increased in the spinal cords of SCC mice (N = 6) at week 5 following SCC inoculation compared to naive mice (N = 5). Western blots were performed to isolate and measure TRPV1; GAPDH was used as the reference protein. **, P < 0.01.
Figure 4
Figure 4
Paw volume was not different across SCC mice treatment groups. A. Paw volume was not different between SAP and IB4-SAP treated SCC mice (N = 6 in each group) at baseline or at week 4. B. Paw volume was not different among capsaicin, JNJ-17203212, or vehicle injected SCC mice at baseline or at week 5. *, P < 0.05; **, P < 0.01.
Figure 5
Figure 5
Ki-67 and 4′,6-diamidino-2-phenylindole (DAPI) immunostaining in paw sections processed at weeks 5 following SCC inoculation. A. An example of Ki-67 and DAPI staining in the paw section of IB4-SAP treated SCC mouse. B. An example of Ki-67 and DAPI staining in the paw section of SAP treated SCC mouse. C. Quantification of Ki-67-positive cells in total DAPI-positive cells showed no difference between IB4-SAP and SAP treated mice. Horizontal scale bar, 100 μm.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Meuser T, Pietruck C, Radbruch L, Stute P, Lehmann KA, Grond S. Symptoms during cancer pain treatment following WHO-guidelines: a longitudinal follow-up study of symptom prevalence, severity and etiology. Pain. 2001;10:247–257. doi: 10.1016/S0304-3959(01)00324-4. - DOI - PubMed
    1. Schwei MJ, Honore P, Rogers SD, Salak-Johnson JL, Finke MP, Ramnaraine ML, Clohisy DR, Mantyh PW. Neurochemical and cellular reorganization of the spinal cord in a murine model of bone cancer pain. J Neurosci. 1999;10:10886–10897. - PMC - PubMed
    1. Molliver DC, Radeke MJ, Feinstein SC, Snider WD. Presence or absence of TrkA protein distinguishes subsets of small sensory neurons with unique cytochemical characteristics and dorsal horn projections. J Comp Neurol. 1995;10:404–416. doi: 10.1002/cne.903610305. - DOI - PubMed
    1. Price TJ, Flores CM. Critical evaluation of the colocalization between calcitonin gene-related peptide, substance P, transient receptor potential vanilloid subfamily type 1 immunoreactivities, and isolectin B4 binding in primary afferent neurons of the rat and mouse. J Pain. 2007;10:263–272. - PMC - PubMed
    1. Albers KM, Woodbury CJ, Ritter AM, Davis BM, Koerber HR. Glial cell-line-derived neurotrophic factor expression in skin alters the mechanical sensitivity of cutaneous nociceptors. J Neurosci. 2006;10:2981–2990. doi: 10.1523/JNEUROSCI.4863-05.2006. - DOI - PMC - PubMed

Publication types

MeSH terms