Inherited alterations of TGF beta signaling components in Appalachian cervical cancers.

PURPOSE: This study examined targeted genomic variants of transforming growth factor beta (TGFB) signaling in Appalachian women. Appalachian women with cervical cancer were compared to healthy Appalachian counterparts to determine whether these polymorphic alleles were over-represented within this high-risk cancer population, and whether lifestyle or environmental factors modified the aggregate genetic risk in these Appalachian women. METHODS: Appalachian women's survey data and blood samples from the Community Awareness, Resources, and Education (CARE) CARE I and CARE II studies (n = 163 invasive cervical cancer cases, 842 controls) were used to assess gene-environment interactions and cancer risk. Polymorphic allele frequencies and socio-behavioral demographic measurements were compared using t tests and χ2 tests. Multivariable logistic regression was used to evaluate interaction effects between genomic variance and demographic, behavioral, and environmental characteristics. RESULTS: Several alleles demonstrated significant interaction with smoking (TP53 rs1042522, TGFB1 rs1800469), alcohol consumption (NQO1 rs1800566), and sexual intercourse before the age of 18 (TGFBR1 rs11466445, TGFBR1 rs7034462, TGFBR1 rs11568785). Interestingly, we noted a significant interaction between "Appalachian self-identity" variables and NQO1 rs1800566. Multivariable logistic regression of cancer status in an over-dominant TGFB1 rs1800469/TGFBR1 rs11568785 model demonstrated a 3.03-fold reduction in cervical cancer odds. Similar decreased odds (2.78-fold) were observed in an over-dominant TGFB1 rs1800469/TGFBR1 rs7034462 model in subjects who had no sexual intercourse before age 18. CONCLUSIONS: This study reports novel associations between common low-penetrance alleles in the TGFB signaling cascade and modified risk of cervical cancer in Appalachian women. Furthermore, our unexpected findings associating Appalachian identity and NQO1 rs1800566 suggests that the complex environmental exposures that contribute to Appalachian self-identity in Appalachian cervical cancer patients represent an emerging avenue of scientific exploration.

Alterations in RD(INK4/ARF) -mediated en bloc regulation of the INK4-ARF locus in human squamous cell carcinoma of the head and neck.

The presence of RD(INK4/ARF) (RD) enhancer in the INK4-ARF locus provides a novel mechanism to simultaneously increase the transcription of p15(INK4b) (p15), p14ARF (p14), and p16(INK4a) (p16). While such upregulation can be repressed through interactions between RD and oncoproteins CDC6 and BMI1, little is known about the involvement of RD in cancer. In this study we investigated RD deletions in 30 squamous cell carcinoma of the head and neck (SCCHN) and the patient-matched High At-Risk Mucosa specimens (HARM, "phenotypically normal" tissues neighboring SCCHN foci but beyond the surgical resection margin). RD was deleted (homozygously/heterozygously) in SCCHN and HARM at the incidence of 36.7% (11/30) and 13.3% (4/30), respectively. In comparison, no RD deletion was detected in 26 oral buccal brush biopsy specimens from healthy donors. Both p16 and p14 were lowly expressed in SCCHN and HARM, and their mRNA expression levels were positively associated with each other (P < 0.01). Moreover, BMI1 was highly expressed in both SCCHN and HARM, and BMI1 overexpression was associated with p16 downregulation in SCCHN (P < 0.05). These results indicate that RD deletion and BMI1 overexpression frequently occur in the early stage of oral carcinogenesis and BMI1 overexpression may downregulate the transcription of p16 and p14 through interfering with RD.

Coordinated expression of cyclin-dependent kinase-4 and its regulators in human oral tumors.

BACKGROUND/AIM: While aberrant expression of cyclin-dependent kinase-4 (CDK4) has been found in squamous cell carcinoma of the head and neck (SCCHN), the associations between CDK4 and its regulators, namely, cyclin D1, cyclin E, gankyrin, SEI1, and BMI1 in gene expression remain to be explored. Herein we investigated the mRNA profiles of these oncogenes and their interrelations in different oral lesion tissues. MATERIALS AND METHODS: Thirty SCCHN specimens and patient-matched high at-risk mucosa (HARM) and 16 healthy control specimens were subjected to quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analyses. RESULTS: The mRNA levels of CDK4, cyclin D1, gankyrin, SEI1, BMI1 were significantly elevated in both HARM and SCCHN (in comparison with control specimens), and statistically significant correlations were found among these markers in gene expression. CONCLUSION: Up-regulation of CDK4 and its regulators takes place in oral cancer progression in a coordinate manner, and HARM and SCCHN share a similar molecular signature within the CDK4-pRB pathway.

NtERF32: a non-NIC2 locus AP2/ERF transcription factor required in jasmonate-inducible nicotine biosynthesis in tobacco.

Nicotine biosynthesis in tobacco (Nicotiana tabacum L.) is highly regulated by jasmonic acid (JA). Two nuclear loci, A and B (renamed NIC1 and NIC2) have been identified that mediate JA-inducible nicotine formation and total alkaloid accumulation. NIC2 was recently shown to be a cluster of seven genes encoding Apetala2/Ethylene-Response Factor (AP2/ERF)-domain transcription factors (TFs) in Group IX of the tobacco AP2/ERF family. Here we report the characterization of several NtERF TF genes that are not within the NIC2 locus, but required for methyl JA (MeJA)-induced nicotine biosynthesis. Expression of NtERF1, NtERF32, and NtERF121 is rapidly induced (<30 min) by MeJA treatment. All three of these TFs specifically bind the GCC box-like element of the GAG motif required for MeJA-induced transcription of NtPMT1a, a gene encoding putrescine N-methyltransferase, the first committed step in the synthesis of the nicotine pyrrolidine ring. Ectopic overexpression of NtERF32 increases expression of NtPMT1a in vivo and elevates total alkaloid contents, whereas RNAi-mediated knockdown of NtERF32 reduces the mRNA levels of multiple genes in the nicotine biosynthetic pathway including NtPMT1a and quinolinate phosphoribosyltransferase (NtQPT2), and lowers nicotine and total alkaloid levels. We conclude that NtERF32 and related ERF genes are important non-NIC2 locus associated transcriptional regulators of nicotine and total alkaloid formation.