Defining the Transcriptional Landscapes of the Tumor Microenvironment of Cervical and Vaginal Cancers at Single-Cell Resolution

PURPOSE/OBJECTIVE(S)

Malignancies found within vaginal tissue are often diagnosed as cancers of the cervix, vulva, or urethra and are clinically treated with similar modalities. However, the rarity of vaginal cancer may be an artifice of categorization; current treatment paradigms do not take into account tissue-specific mutations and differences in mechanistic pathways intracellularly. Understanding the shared and distinctly different transcriptional profiles of vaginal and cervical tumors at a single-cell resolution will provide insights in vaginal tumor biology and will open avenues for future clinical interventions.

MATERIALS/METHODS

Biopsies of tumor and adjacent normal tissue from 9 patients (3 adenocarcinomas (ADC), 3 squamous cell carcinomas (SCC) from the cervix, and 3 vaginal SCC) were collected and analyzed by single-cell RNA sequencing (scRNA-seq) to compare the tumor, immune, and stromal features of cervical and vaginal cancers.

RESULTS

Collectively, over 50,000 cells were analyzed by scRNA-seq in this study. We performed dimensionality reduction and clustering analysis of the single-cell transcriptomes to identify the major cell types composing the vaginal and cervical tumor tissues. Compared to Cervical SCC, Vaginal SCC tissues showed reduced fractions of macrophages (-2.7 log2-fold; padj < 0.02) and T cells (-3.7 log2-fold; padj < 0.02) by differential cell proportion analysis (RAISIN). Likewise, the vaginal SCC epithelial cell compartments showed downregulation of inflammatory pathways including TNF signaling via NFKB (NES = -5.7, padj = 5.0 × 10-19), IL2 STAT5 signaling (NES = -4.5, padj = 1.6 × 10-12), and interferon gamma response (NES = -4.3, padj = 9.4 × 10-12), among the Hallmark pathway collection. On the other hand, vaginal SCC epithelial cells showed significant upregulation of oxidative phosphorylation (NES = 4.8, padj = 1.7 × 10-17), p53 pathway (NES = 4.2, padj = 1.8 × 10-13), mTORC1 signaling (NES = 4.2, padj = 1.9 × 10-13), and estrogen early and late response (NES = 4.0, padj < 7.5 × 10-12) compared to cervical SCC.

CONCLUSION

These results highlight distinct differences in the cell type composition and cancer epithelial pathways in vaginal vs. cervical SCC. Among upregulated pathways in vaginal SCC, ER and mTORC1 pathway activation may represent targets for therapeutic intervention worthy of further investigation.

Second messengers mediating mechanical responses to the FARP GYIRFamide in the fluke Fasciola hepatica

Spontaneous phasic contractions recorded from isolated body strips of Fasciola hepatica were increased in frequency and amplitude by GYIRFamide, an FMRFamide-related peptide (FaRP). Superfusion with guanosine 5'-O-(2-thiodiphosphate) (100 microM, n = 5) reduced the effects of GYIRFamide on both frequency (by 82%) and amplitude (by 75%). The adenylate cyclase inhibitor MDL-12330A (25 microM) increased spontaneous activity. MDL-12330A completely inhibited the frequency response to GYIRFamide and reduced the amplitude response by 66% as measured relative to this elevated basal activity (n = 6). Inhibition of phospholipase C (PLC) with neomycin sulfate (1 mM) had no direct effect on activity but reduced the frequency response to GYIRFamide by 64% and the amplitude increase by 95% (n = 9). The protein kinase C (PKC) inhibitor chelerythrine chloride (10 microM) also reduced frequency and amplitude responses by 98 and 99%, respectively, without affecting basal contractility (n = 5). Phorbol 12-myristate 13-acetate, an activator of PKC, increased contraction frequency and amplitude (n = 6). It was concluded that GYIRFamide stimulates mechanical activity in F. hepatica through a G protein, via a PLC- and PKC-dependent second messenger pathway.

Ionic mechanisms underlying spontaneous muscle contractions in the liver fluke, Fasciola hepatica

Spontaneous contractions of liver fluke muscle were abolished in Ca(2+)-free saline and by 100 microM nifedipine and reduced by 5 mM cadmium chloride, suggesting that they are dependent on extracellular Ca(2+). Caffeine (5 mM) significantly increased contraction amplitude and frequency. Ryanodine (100 microM) failed to block the caffeine response but significantly reduced spontaneous contraction frequency, suggesting that intracellular stores have a functional role. Cyclopiazonic acid (5 microM) had no effect on the caffeine response or spontaneous activity. 3-Isobutyl-1-methylxanthine (IBMX), forskolin, and 8-bromoadenosine 3',5'-cyclic monophosphate significantly increased spontaneous contractions, which implies that cAMP has a regulatory function in motility. Caffeine, however, produced no measurable increase in cAMP. The caffeine effect was inhibited by cadmium chloride and nifedipine, whereas IBMX-induced increases in amplitude were reduced by cadmium chloride. Thus caffeine and cAMP appear capable of opening plasma membrane Ca(2+) channels, but the involvement of cAMP in caffeine responses has not been proved.

The effects of FaRPs on the motility of isolated muscle strips from the liver fluke, Fasciola hepatica

The effects of a range of FMRFamide-related peptides (FaRPs) on isometric contractility were tested using isolated muscle strips from the liver fluke, F. hepatica. The neuropeptides tested were the molluscan FaRPs, FMRFamide and FLRFamide, the turbellarian FaRPs, RYIRFamide and GYIRFamide, the cestode peptides, NPF and GNFFRFamide, and the nematode FaRPs, AF-1 (KNEFIRFamide), AF-2 (KHEYLRFamide), AF-8 (KSAYMRFamide), and PF-4 (KPNFIRFamide). Dose-response experiments were undertaken at a concentration range of 5 nM-5 microM for all of the neuropeptides tested. FMRFamide and AF-8 caused statistically significant increases in the amplitude and frequency of contractions at concentrations of 0.5 microM and 5 microM. FLRFamide and AF-2 also caused significant increases in contraction frequency at concentrations of 0.5 microM and 5 microM, although a significant increase in amplitude of contraction was observed only at a concentration of 5 microM. GYIRFamide increased both amplitude and frequency significantly at concentrations of 50 nM, 0.5 microM and 5 microM. RYIRFamide significantly increased frequency of contractions at concentrations of 0.5 microM and 5 microM, but failed to have a significant effect on contraction amplitude. AF-1 at a concentration of 5 microM increased contraction amplitude, but failed to have an effect on frequency at any of the concentrations used. PF-4 caused a statistically significant increase in both the amplitude and frequency of contractions at a concentration of 5 microM. NPF and GNFFRFamide had no effect on the in vitro motility of F. hepatica over the range of concentrations tested. The results are discussed in the light of possible structure-activity relationships in the FaRPs tested.

Quantitative autoradiographic evidence for insulin receptors in the choroid plexus of the rat brain

Techniques of in vitro receptor autoradiography were used to visualize binding of 125I-insulin on slices of frozen rat brain. Slide-mounted sections of frozen rat brain were incubated in 0.05 nM porcine 125I-monoiodoinsulin, alone or mixed with 1 microM unlabeled porcine insulin, ribonuclease, or glucagon, for 2 h at 22 degrees C. The labeled brain slices were apposed to LKB Ultrofilm to generate autoradiograms. The method permitted equal access of labeled insulin to both sides of the blood-brain barrier and localization of insulin binding sites in small anatomic regions. Quantitative estimates of specific iodoinsulin binding were made by computer digital image densitometry of the autoradiographic film images. High concentrations of specific binding sites for iodoinsulin were present in the choroid plexus of the lateral (26.9 +/- 2.0 X 10(-3) fmol/mm2), fourth (18.3 +/- 3.0 X 10(-3) fmol/mm2), and third (13.2 +/- 1.5 X 10(-3) fmol/mm2) ventricles (insulin binding is expressed per unit area of autoradiographic image). Binding to the third ventricular choroid plexus was similar to the concentrations observed for liver slices and the external plexiform layer of the olfactory bulb. Specific binding of iodoinsulin in the cingulate cortex and other surrounding regions was less than in choroid plexus. Ribonuclease or glucagon had no measurable effect on binding when mixed with labeled insulin. The results support the hypothesis that the choroid plexus has a high density of receptors for insulin, and suggests that the choroid plexus may be a target of CSF insulin action and/or a site of insulin transport into the CSF.