Targeting KRAS in non-small-cell lung cancer: recent progress and new approaches.

Rat sarcoma (RAS) is the most frequently mutated oncogene in human cancer, with Kirsten rat sarcoma (KRAS) being the most commonly mutated RAS isoform. Overall, KRAS accounts for 85% of RAS mutations observed in human cancers and is present in 35% of lung adenocarcinomas (LUADs). While the use of targeted therapies and immune checkpoint inhibitors (CPIs) has drastically changed the treatment landscape of advanced non-small-cell lung cancer (NSCLC) in recent years, historic attempts to target KRAS (both direct and indirect approaches) have had little success, and no KRAS-specific targeted therapies have been approved to date for patients in this molecular subset of NSCLC. With the discovery by Ostrem, Shokat, and colleagues of the switch II pocket on the surface of the active and inactive forms of KRAS, we now have an improved understanding of the complex interactions involved in the RAS family of signaling proteins which has led to the development of a number of promising direct KRASG12C inhibitors, such as sotorasib and adagrasib. In previously treated patients with KRASG12C-mutant NSCLC, clinical activity has been shown for both sotorasib and adagrasib monotherapy; these data suggest promising new treatment options are on the horizon. With the stage now set for a new era in the treatment of KRASG12C-mutated NSCLC, many questions remain to be answered in order to further elucidate the mechanisms of resistance, how best to use combination strategies, and if KRASG12C inhibitors will have suitable activity in earlier lines of therapy for patients with advanced/metastatic NSCLC.

Vaping, Smoking and Lung Cancer Risk.

Nicotine exposure through the use of electronic delivery systems (vaping) has been found to elevate the risk of certain conditions of the lungs, e.g., vaping associated lung injury, EVALI). However, the potential impact of vaping on lung cancer risk remains unexplored. We, therefore, examined the association of vaping and cigarette smoking with lung cancer risk in a case control study conducted in central Ohio. The study design compared 4,975 individuals with recently diagnosed pathologically confirmed carcinoma of the lung to 27,294 controls without cancer that were group matched at a 5:1 ratio to the cases by age, gender, race and location of residence. Odds ratios (OR) adjusted for gender, age and race revealed a fourfold higher risk of lung cancer among individuals who vaped in combination with chronic smoking (OR=58.9, 95% CI=47.3-70.5) versus individuals who only smoked cigarettes (OR=13.9, 95% CI=12.7-15.3, P<0.001). Further adjustment for prevalent comorbidities, chronic obstructive pulmonary disease and coronary artery disease, reduced the magnitude of the OR, but the risk for vaping and smoking (OR=38.7, 95% CI =31.5-47.6) remained fourfold higher than for smoking alone (OR=9.6, 95% CI=8.7-10.6, P<0.001). This finding was consistent for men and women, with adjustment for pack-years of smoking, and for the main histological cell types of lung cancer. Our results suggest that the addition of vaping to smoking accelerates the risk of developing lung cancer.

A functionally defective allele of TAP1 results in loss of MHC class I antigen presentation in a human lung cancer.

Tumours express a variety of novel epitopes which represent potential immune targets, and thus clinically evident tumours are thought to have effectively avoided immune recognition and elimination. Transporters associated with antigen presentation (TAP) are thought to be responsible for conveying intracellular peptides into the endoplasmic reticulum for complex formation with class I MHC and subsequent recognition by cytotoxic T lymphocytes. In this study, we evaluated 79 human solid tumours and cell lines for genetic abnormalities in TAP1 that might have led to an acquired loss of antigen presenting ability. A novel sequence (R659Q) was discovered near the ATP binding site in a human small cell lung cancer (SCLC) cell line, H1436. This cell line is heterozygous for this allele, but only the R659Q allele is transcribed into RNA. Even though the R659Q protein is expressed, these cells act as if they were TAP deficient by peptide binding and antigen presentation studies, which are restored after transfection of a functional TAP1 allele. This is the first evidence for a naturally occuring protein structural defect resulting in defective peptide transport in a human solid tumour.

Genomic characterization of thymic epithelial tumors in a real-world dataset.

BACKGROUND: Thymic epithelial tumors (TETs) are rare neoplasms arising in the mediastinum, including thymic carcinomas and thymomas. Due to their rarity, little is known about the genomic profiles of TETs. Herein, we investigated the genomic characteristics of TETs evaluated in a large comprehensive genomic profiling database in a real-world setting. METHODS: We included data from two different cohorts: Foundation Medicine Inc. (FMI) in the United States and the Center for Cancer Genomics and Advanced Therapeutics (C-CAT) in Japan. Samples profiled were examined for all classes of alterations in 253 genes targeted across all assays. Tumor mutational burden (TMB) and microsatellite instability (MSI) were also evaluated. RESULTS: A total of 794 patients were collected in our study, including 722 cases from FMI and 72 cases from C-CAT. In the FMI data, CDKN2A (39.9%), TP53 (30.2%) and CDKN2B (24.6%) were frequently altered in thymic carcinoma, versus TP53 (7.8%), DNMT3A (6.8%), and CDKN2A (5.8%) in thymoma. TMB-high (≥10 mutations/Mb) and MSI were present in 7.0% and 2.3% of thymic carcinomas, and 1.6% and 0.3% of thymomas, respectively. Within C-CAT data, CDKN2A (38.5%), TP53 (36.5%) and CDKN2B (30.8%) were also frequently altered in thymic carcinoma, while alterations of TSC1, SETD2 and LTK (20.0% each) were found in thymoma. CONCLUSIONS: To the best of our knowledge, this is the largest cohort in which genomic alterations, TMB and MSI status of TETs were investigated. Potential targets for treatment previously unbeknownst in TETs are identified in this study, entailing newfound opportunities to advance therapeutic development.

Production of vascular endothelial growth factor by human tumors inhibits the functional maturation of dendritic cells.

Inadequate presentation of tumor antigens by host professional antigen-presenting cells (APCs), including dendritic cells (DCs), is one potential mechanism for the escape of tumors from the host immune system. Here, we show that human cancer cell lines release a soluble factor or factors that dramatically affect DC maturation from precursors without affecting the function of relatively mature DCs. One factor responsible for these effects was identified as vascular endothelial growth factor (VEGF). Thus, VEGF may play a broader role in the pathogenesis of cancer than was previously thought, and therapeutic blockade of VEGF action may improve prospects for immunotherapy as well as inhibit tumor neovasculature.

First-line nivolumab plus ipilimumab with two cycles of chemotherapy versus chemotherapy alone (four cycles) in advanced non-small-cell lung cancer: CheckMate 9LA 2-year update.

BACKGROUND: To further characterize survival benefit with first-line nivolumab plus ipilimumab with two cycles of chemotherapy versus chemotherapy alone, we report updated data from the phase III CheckMate 9LA trial with a 2-year minimum follow-up. PATIENTS AND METHODS: Adult patients were treatment naïve, with stage IV/recurrent non-small-cell lung cancer, no known sensitizing EGFR/ALK alterations, and an Eastern Cooperative Oncology Group performance status ≤1. Patients were randomized 1 : 1 to nivolumab 360 mg every 3 weeks plus ipilimumab 1 mg/kg every 6 weeks with two cycles of chemotherapy, or four cycles of chemotherapy. Updated efficacy and safety outcomes are reported, along with progression-free survival (PFS) after next line of treatment (PFS2), treatment-related adverse events (TRAEs) by treatment cycle, and efficacy outcomes in patients who discontinued all treatment components in the experimental arm due to TRAEs. RESULTS: With a median follow-up of 30.7 months, nivolumab plus ipilimumab with chemotherapy continued to prolong overall survival (OS) versus chemotherapy. Median OS was 15.8 versus 11.0 months [hazard ratio 0.72 (95% confidence interval 0.61-0.86)]; 2-year OS rate was 38% versus 26%. Two-year PFS rate was 20% versus 8%. ORR was 38% versus 25%, respectively; 34% versus 12% of all responses were ongoing at 2 years. Median PFS2 was 13.9 versus 8.7 months. Improved efficacy outcomes in the experimental versus control arm were observed across most subgroups, including by programmed death-ligand 1 and histology. No new safety signals were observed; onset of grade 3/4 TRAEs was mostly observed during the first two treatment cycles in the experimental arm. In patients who discontinued all components of nivolumab plus ipilimumab with chemotherapy treatment due to TRAEs (n = 61) median OS was 27.5 months; 56% of responders had an ongoing response ≥1 year after discontinuation. CONCLUSIONS: With a 2-year minimum follow-up, nivolumab plus ipilimumab with two cycles of chemotherapy provided durable efficacy benefits over chemotherapy with a manageable safety profile and remains an efficacious first-line treatment of advanced non-small-cell lung cancer.

Newly diagnosed patients with advanced non-small cell lung cancer: A clinical description of those with moderate to severe depressive symptoms.

OBJECTIVES: The aims of this observational study were to 1) accrue newly diagnosed patients with advanced-stage non-small cell lung cancer (NSCLC) awaiting the start of first-line treatment and identify those with moderate to severe depressive symptoms and, 2) provide a clinical description of the multiple, co-occurring psychological and behavioral difficulties and physical symptoms that potentially exacerbate and maintain depressive symptoms. MATERIALS AND METHODS: Patients with stage IV NSCLC (N = 186) were enrolled in an observational study (ClinicalTrials.gov Identifier: NCT03199651) and completed the American Society of Clinical Oncology-recommended screening measure for depression (Patient Health Questionnaire-9 [PHQ-9]). Individuals with none/mild (n = 119; 64 %), moderate (n = 52; 28 %), and severe (n = 15; 8 %) depressive symptoms were identified. Patients also completed measures of hopelessness, generalized anxiety disorder (GAD) symptoms, stress, illness perceptions, functional status, and symptoms. RESULTS: Patients with severe depressive symptoms reported concomitant feelings of hopelessness (elevating risk for suicidal behavior), anxiety symptoms suggestive of GAD, and traumatic, cancer-specific stress. They perceived lung cancer as consequential for their lives and not controllable with treatment. Pain and multiple severe symptoms were present along with substantial functional impairment. Patients with moderate depressive symptoms had generally lower levels of disturbance, though still substantial. The most salient differences were low GAD symptom severity and fewer functional impairments for those with moderate symptoms. CONCLUSIONS: Depressive symptoms of moderate to severe levels co-occur in a matrix of clinical levels of anxiety symptoms, traumatic stress, impaired functional status, and pain and other physical symptoms. All of the latter factors have been shown, individually and collectively, to contribute to the maintenance or exacerbation of depressive symptoms. As life-extending targeted and immunotherapy use expands, prompt identification of patients with moderate to severe depressive symptoms, referral for evaluation, and psychological/behavioral treatment are key to maximizing treatment outcomes and quality of life for individuals with advanced NSCLC.

Cloned fusion product from a rare t(15;19)(q13.2;p13.1) inhibit S phase in vitro.

BACKGROUND: Somatically acquired chromosomal translocation is a common mechanism of oncogene activation in many haematopoietic tumours and sarcomas. However, very few recurrent chromosomal translocations have been reported in more common epithelial tumours such as lung carcinomas. METHODS: We established a cell line HCC2429 from an aggressive, metastatic lung cancer arising in a young, non-smoking woman, demonstrating a t(15;19)(q13.2;p13.1). The breakpoints on chromosomes 15 and 19 were cloned using long distance inverse PCR and we determined by RT-PCR that the translocation results in a novel fusion transcript in which the 3' end Brd4 on chromosome 19p is fused to the 5' end of NUT on chromosome 15q. RESULTS: In total, 128 lung cancer tissues were screened using fluorescent in situ hybridisation, but none of the tumours screened demonstrated t(15;19), suggesting that this translocation is not commonly found in lung cancer. Consistent with previous literature, ectopic expression of wild type Brd4 was shown to inhibit G(1) to S progression. However, we also found that the Brd4-NUT fusion augments the inhibition of progression to S phase compared with wild type Brd4. CONCLUSION: Alteration in cell cycle kinetics is important in tumorigenesis, although the exact role of Brd4-NUT fusion protein in the pathogenesis of lung cancers remains unclear and need to be further elucidated.

Antibodies against autologous tumor cell proteins in patients with small-cell lung cancer: association with improved survival.

BACKGROUND: The frequency and clinical relevance of human antitumor immune responses is not well known, and few target antigens have been identified. PURPOSE: This study was designed to determine the frequency of antibodies reactive against extracts of autologous tumor cell lines and to correlate these data with survival. METHODS: Serum samples were obtained from 40 lung cancer patients treated on National Cancer Institute protocols. These sera were used as probes in immunoblots against protein extracts from tumor cell lines derived from each of these patients. RESULTS: We detected serum antibodies against autologous tumor cell proteins in 21 (58%) of the 36 patients with small-cell lung cancer (SCLC) and three (75%) of the four with non-small-cell lung cancer (NSCLC). Two patients' sera detected the p53 tumor suppressor gene product and two detected the product of the HuD gene (associated with paraneoplastic neurological syndromes) in their autologous tumor cell lysates. SCLC patients with antibodies against autologous tumor cell proteins had improved survivals compared with those in the antibody-negative group (P = .059). All patients who lived longer than 36 weeks were antitumor antibody positive. Sera from six (86%) of seven patients with limited disease were positive for antibodies that reacted against autologous tumor cells, compared with 15 of 29 (52%) of sera from patients with extensive disease. CONCLUSIONS: Our results suggest that the sera from patients with SCLC frequently contain antibodies against tumor cell proteins and that these antibodies are associated with improved survival. IMPLICATIONS: These data suggest that an antitumor immune response may affect tumor growth, and that the anonymous proteins detected by antitumor antibodies in lung cancer patient sera may represent proteins involved in the development of lung cancer or in its clinical manifestations.

Evidence for selection against human lung cancers bearing p53 missense mutations which occur within the HLA A*0201 peptide consensus motif.

Short peptide fragments of intracellular proteins that fit a defined sequence motif bind to the most common human major histocompatibility complex class I molecule, HLA A*0201, and mediate killing by cytotoxic T-cells [D.F. Hunt et al., Science (Washington DC), 255: 1261-1263, 1992; K. Falk et al., Nature (Lond.), 351: 290-296, 1991]. The existence of such a motif allows prediction of whether novel peptides derived from mutant oncoporteins might be presented on the surface of cancer cells bearing that HLA allele. Clinical cancer might develop only when these mutations occur outside a major histocompatibility complex binding motif or in those cells that acquire defects in antigen presentation. Here, we find that missense mutations of p53 from a variety of tumors fall within the HLA A*0201 motif less often than would be expected if the location of mutations and motifs were independent. When we analyzed the HLA subtype of lung cancer cell lines with known p53 missense mutations, we found that all of the mutant oncopeptides predicted to be presentable by HLA A*0201 came from tumors that either did not carry the A*0201 allele or had lost that allele in the process of tumorigenesis. Presentation of mutant oncogene peptides on class I major histocompatibility complex might thus represent a physiologically significant selection pressure in the development of human cancer.

Neural cell adhesion molecule expression and messenger RNA splicing patterns in lung cancer cell lines are correlated with neuroendocrine phenotype and growth morphology.

Diverse histological types of lung cancer express neuroendocrine (NE) markers. We studied the expression and alternative splicing forms of the neural cell adhesion molecule (NCAM) NKH-1, a member of the immunoglobulin superfamily, in 56 lung cancer cell lines representing all histological types. We found a strong correlation between expression of NCAM with both NE phenotype and lack of substrate adhesion in culture. Several cell lines expressed high levels of the leukocyte antigen Leu-7 (HNK-1) but were negative for NCAM antigen and mRNA, indicating that the Leu-7 antigen is distinct from NCAM. All of the NCAM-positive cell lines demonstrate a single 6.2-kilobase mRNA, and analysis of the known 3' alternative splices shows predominant expression of only the membrane form with the small intracytoplasmic domain. We conclude that (a) expression of NCAM is associated with NE phenotype regardless of the histological type of lung cancer; (b) these cell lines share a single form of NCAM; (c) with few exceptions, NCAM expression is associated with cell to cell adhesion and lack of substrate adhesion (growing as floating clusters); and (d) Leu-7 antigen is distinct from NCAM. This form of NCAM may play a functional role in NE differentiation or may be a part of the NE program expressed by these cells.

Development of antibodies against p53 in lung cancer patients appears to be dependent on the type of p53 mutation.

Using immunoblotting techniques we studied the sera from small cell lung cancer and non-small cell lung cancer patients for antibodies directed against p53. We have also characterized the majority of these patients' tumors for p53 mutations. In the sera of 13% of the patients (4 of 40 small cell lung cancer and 2 of 6 non-small cell lung cancer) we found antibodies specific for the p53 tumor suppressor gene product. All of the antibody-positive patients tested had p53 missense mutations and expressed detectable p53 antigen in their tumor cell lines. No anti-p53 antibodies were detected in sera from patients whose tumor had p53 stop, splice/stop, splice, or frameshift mutations (n = 10). Thus, while we find that the ability of lung cancer patients to develop anti-p53 antibodies is correlated with the type of p53 mutation, many patients have tumors with missense p53 mutations and did not develop anti-p53 antibodies. The presence of p53 antibodies was not correlated to stage, prior treatment, sex, or survival. None of these lung cancer patient sera had measurable amounts of p53 antigen. By immunoblotting all six anti-p53 antisera we were able to detect a variety of mutant p53 proteins (including those from antibody-negative patients) and detected wild-type p53 protein. The development of anti-p53 antibodies represents an interesting model system for studying immune responses in cancer patients against mutant oncogene products.

Molecular analysis of the HuD gene encoding a paraneoplastic encephalomyelitis antigen in human lung cancer cell lines.

Small cell lung cancer (SCLC) is known to express the HuD protein, the neuronal antigen homologous to Drosophila Elav and Sxl genes involved in neuronal and sex development. HuD is the target of an immune response including high titered antibodies causing paraneoplastic encephalomyelitis and sensory neuropathy. Because the p53 recessive oncogene is mutated and anti-p53 antibodies frequently occur in cancer patients, we wondered if the development of anti-HuD antibodies signaled the presence of HuD mutations in lung cancer. The HuD gene was mapped to chromosome region 1p using a human-mouse hybrid cell panel. We confirmed that 26 of 46 cancer (43 lung cancer and 3 mesothelioma) cell lines expressed HuD mRNA and that this expression, as well as protein expression by Western blot, correlated strongly with the SCLC neuroendocrine phenotype. Southern blot and single-strand conformation polymorphism analyses showed that HuD was not mutated in 78 lung cancers, including patients with the severe paraneoplastic syndrome. Northern blot analysis showed that lung cancer cell lines expressed two major mRNAs (4.3 and 4.0 kilobases) of HuD. We found the three previously described alternative spliced mRNA forms (HuDpro, HuD, and HuDmex). In addition, we also found HuD mRNA had an alternative splicing form in its 5'-coding region. This alternative splice introduced 87 base pairs of sequence and a termination codon resulting in a predicted small, truncated protein (11 amino acids) reminiscent of the male-specific truncated protein in the Sex-lethal (Sxl) gene of Drosophila. However, mRNAs encoding both full-length and truncated proteins were expressed in all SCLCs. These results show that the HuD gene is not mutated in lung cancer, including tumors from patients producing anti-HuD antibodies, but HuD expression is an independent marker or determinant of the neuroendocrine differentiation seen in SCLC.

Polymorphic sites within the MCC and APC loci reveal very frequent loss of heterozygosity in human small cell lung cancer.

Using single-strand conformation polymorphism we have found two polymorphic sites, AAC to AAT at codon 511 (exon 12) and GCT to GCG at codon 708 (exon 15), in the MCC gene. These sites and an RsaI polymorphic site in APC allowed us to study 23 human small cell lung cancer (SCLC) and 7 non-small cell lung cancer samples for allele loss. Of the 23 SCLC samples, 21 (91%) were informative for one or more of these markers, and we found allele loss in more than 80% (17 of 21). In non-small cell lung cancer samples, 5 of 7 (71%) were informative, and reduction or loss of one allele was found in 2 of 5 (40%). Seven cases were informative for both genes, loss of heterozygosity occurred for both genes in five, one retained heterozygosity for both, and one SCLC had loss of heterozygosity for APC but not for MCC. We conclude that loss of heterozygosity occurs frequently for MCC and APC in lung cancer of all histological types and is very frequent in SCLC. This suggests the presence of tumor suppressor gene(s) in the MCC/APC region of 5q21 involved in human lung cancer.

A mutant p53 tumor suppressor protein is a target for peptide-induced CD8+ cytotoxic T-cells.

Cytotoxic T-lymphocytes (CTL) recognize processed peptide fragments of any endogenous protein, after these peptides are carried to the cell surface by class I major histocompatibility molecules. Thus, a tumor antigen does not have to be expressed as an intact protein on the cell surface to be recognizable by CTL. However, mutant oncogene products have not yet been shown to be targets of CD8+ CTL. Here, we generate p53-specific CD8+ CTL by immunizing BALB/c mice with spleen cells pulsed with a peptide, corresponding to a 21-amino acid sequence encompassing a point mutation (135 Cys to Tyr) in the mutant p53 gene product from a human lung carcinoma. The mutation created a new Kd class I molecule binding motif sequence, and the determinant recognized was mapped to this motif and presented by the Kd class I molecule. The wild type peptide, without the mutation, was not recognized. Importantly, the CTL killed specifically BALB/c fibroblasts transfected with the mutant p53 gene and endogenously expressing the mutant protein, but not control fibroblasts or ones transfected with a different human mutant p53 gene. Thus, endogenously synthesized mutant p53, at levels found in tumors, can render cells targets for specific CTL, and these CTL can be generated by peptide immunization. These findings point the way toward an approach to selective immunotherapy against tumors.

Antitumor effects of an adenovirus expressing antisense insulin-like growth factor I receptor on human lung cancer cell lines.

Insulin-like growth factors (IGFs) are often essential for the maintenance of the malignant phenotype, and in lung cancer the IGF-I receptor (IGF-Ir) is often expressed at high levels. Stable transfection of antisense plasmids expressing the first 300 bp of the IGF-Ir reduces the tumorigenicity of a variety of tumor cell lines and has been reported to induce systemic antitumor effects on established, non-gene-modified tumors in animal model systems. We have constructed an adenovirus expressing an antisense IGF-Ir (Ad-IGF-Ir/as) in an attempt to develop these observations into a clinical therapeutic approach. A single transduction by Ad-IGF-Ir/as (at a multiplicity of infection of 10:1) decreased the IGF-Ir number by about 50% in human lung cancer cell lines NCI H460 and SCC5, as measured by an 125I-labeled IGF-I competitive binding assay. After the transduction of these human lung cancer cell lines by Ad-IGF-Ir/as, the soft agar clonogenicity was reduced by 84%. The i.p. treatment of nude mice bearing established i.p. NCI H460 cells resulted in prolonged survival compared to that of nude mice treated with a reporter virus. These results suggest that Ad-IGF-Ir/as has a therapeutic effect on established human lung cancer xenografts and may represent an effective and practical cancer gene therapy strategy.

Vascular endothelial growth factor effects on nuclear factor-kappaB activation in hematopoietic progenitor cells.

Vascular endothelial growth factor (VEGF) inhibits of the activation of transcription factor nuclear factor-kappaB (NF-kappaB) in hematopoietic progenitor cells (HPCs), and this is associated with alterations in the development of multiple lineages of hematopoietic cells and defective immune induction in tumor-bearing animals. Antibodies to VEGF have been shown to abrogate this effect. The mechanism by which VEGF antagonizes the induction of NF-kappaB was investigated in this study. Using supershift electrophoretic mobility shift analysis, we found that although tumor necrosis factor alpha (TNF-alpha) induced the nuclear translocation and DNA binding of p65-containing complexes, VEGF alone induced nuclear translocation and DNA binding of the complexes containing RelB. These results were confirmed by immunofluorescence confocal microscopy. VEGF effectively blocked TNF-alpha-induced NF-kappaB activation in HPCs from RelB-/- mice, however, similar to the effect observed in HPCs obtained from RelB+/- and RelB+/+ mice. This suggests that RelB is not required for VEGF to inhibit NF-kappaB activation. However, although TNF-alpha induced rapid activation of IkappaB kinase (IKK) as expected, this activity was substantially reduced in the presence of VEGF. This decreased IKK activation correlated with the inhibition of IkappaB alpha phosphorylation and degradation of IkappaB alpha and IkappaB epsilon in HPCs. VEGF alone, however, did not have any effect on phosphorylation of IkappaB alpha or degradation of IkappaB alpha and other inhibitory molecules IkappaB beta, IkappaB epsilon, or Bcl-3. SU5416, a potent inhibitor of the VEGF receptor I (VEGFR1) and VEGFR2 receptor tyrosine kinases, did not abolish the inhibitory effect of VEGF, indicating that the VEGF effect is mediated by a mechanism unrelated to VEGFR1 or VEGFR2 tyrosine kinase activity. Thus, VEGF appears to inhibit TNF-alpha-induced NF-kappaB activation by VEGFR kinase-independent inhibition of IKK. Therapeutic strategies aimed at overcoming VEGF-mediated defects in immune induction in tumor-bearing hosts will need to target this kinase-independent pathway.

Interleukin 2 production in vitro by peripheral lymphocytes in response to human papillomavirus-derived peptides: correlation with cervical pathology.

Human papillomavirus (HPV) is believed to be the major cause of cervical cancer. To investigate whether a cellular immune response, especially a T helper type 1 response, is related to the natural defense against HPV-related cervical lesions, the interleukin 2 response of peripheral blood lymphocytes in vitro to overlapping peptides from HPV-16 E6 and E7 oncoproteins was compared with the degree of cervical cytological abnormality among 140 women in a cross-sectional study. We compared 66 women diagnosed with low-grade squamous intraepithelial lesions (LSIL), 21 with high-grade squamous intraepithelial lesions (HSIL), and 28 with invasive cervical cancer with 25 women who were cytologically normal but previously HPV-16 DNA positive. The fraction showing strong interleukin 2 production against HPV-16 peptides was greatest among cytologically normal women (35%) and declined with increasing disease severity [LSIL] (20%), HSIL, (17%), and cancer patients (7%); X2 test P for the trend = 0.02], whereas the responses against a recall influenza antigen were not significantly different among groups. Our finding suggests that a T helper lymphocyte type 1 response to HPV antigens is associated with disease status. This result may reflect a targeted effect of the disease on immune function or a protective effect of the immune response against disease progression.

LKB1 deficiency enhances sensitivity to energetic stress induced by erlotinib treatment in non-small-cell lung cancer (NSCLC) cells.

The tumor suppressor serine/threonine kinase 11 (STK11 or LKB1) is mutated in 20-30% of patients with non-small-cell lung cancer (NSCLC). Loss of LKB1-adenosine monophosphate-activated protein kinase (AMPK) signaling confers sensitivity to metabolic inhibition or stress-induced mitochondrial insults. We tested the hypothesis that loss of LKB1 sensitizes NSCLC cells to energetic stress induced by treatment with erlotinib. LKB1-deficient cells exhibited enhanced sensitivity to erlotinib in vitro and in vivo that was associated with alterations in energy metabolism and mitochondrial dysfunction. Loss of LKB1 expression altered the cellular response to erlotinib treatment, resulting in impaired ATP homeostasis and an increase in reactive oxygen species. Furthermore, erlotinib selectively blocked mammalian target of rapamycin signaling, inhibited cell growth and activated apoptosis in LKB1-deficient cells. Erlotinib treatment also induced AMPK activation despite loss of LKB1 expression, which was partially reduced by the application of a calcium/calmodulin-dependent protein kinase kinase 2 inhibitor (STO-609) or calcium chelator (BAPTA-AM). These findings may have significant implications for the design of novel NSCLC treatments that target dysregulated metabolic and signaling pathways in LKB1-deficient tumors.