Phase Ib dose-escalation study of the hypoxia-modifier myo-inositol trispyrophosphate in patients with hepatopancreatobiliary tumors

Objective

Hypoxia is present in most solid tumors and acts as a driver of malignancy. Myo-inositol trispyrophosphate (ITPP) is a novel re-oxygenating compound without apparent toxicity. In preclinical models, it potentiates the efficacy of subsequent chemotherapy through vascular normalization. We sought to assess the safety, tolerability, and preliminary efficacy of ITPP.

Methods

In this monocentric, open-label, dose-escalation study following a 3+3 design, eligible patients with advanced primary and secondary hepatopancreatobiliary tumors received nine 8-h infusions of ITPP during 3 weeks across eight dose levels (1866–14,500 mg/m2/dose), followed by standard chemotherapy. Primary endpoints were safety and tolerability. Secondary endpoints were pharmacokinetics and estimation of efficacy based on radiological responses and angiogenic serum markers. Registration number: NCT02528526.

Results

From April 2015 to July 2018, a total of 28 enrolled patients were assessed for the primary endpoints. ITPP was safe up to single doses of 12,390 mg/m2, and 32 ITPP-related adverse events occurred: 19 (67.8%) hypercalcemia, 5 (17.8%) hyponatremia, and 4 (14.2%) hypomagnesemia. Following ITPP monotherapy, 52% of patients displayed morphological disease stabilization. Following subsequent chemotherapy, 10% showed a partial response, and 60% had stable disease. Angiogenic markers were decreased in 60% after ITPP and tended to correlate with responses and survival after chemotherapy.

Conclusion

Administration of ITPP is safe up to 12,390 mg/m2 with favorable pharmacokinetics. Preliminary translational efficacy data show decreased angiogenic markers, which might indicate an anti-hypoxic effect and enhancement of chemotherapy through ITPP.

Reduced expression of a gene proliferation signature is associated with enhanced malignancy in colon cancer

The association between cell proliferation and the malignant potential of colon cancer is not well understood. Here, we evaluated this association using a colon-specific gene proliferation signature (GPS). The GPS was derived by combining gene expression data obtained from the analysis of a cancer cell line model and a published colon crypt profile. The GPS was overexpressed in both actively cycling cells in vitro and the proliferate compartment of colon crypts. K-means clustering was used to independantly stratify two cohorts of colon tumours into two groups with high and low GPS expression. Notably, we observed a significant association between reduced GPS expression and an increased likelihood of recurrence (P<0.05), leading to shorter disease-free survival in both cohorts. This finding was not a result of methodological bias as we verified the well-established association between breast cancer malignancy and increased proliferation, by applying our GPS to public breast cancer data. In this study, we show that reduced proliferation is a biological feature characterizing the majority of aggressive colon cancers. This contrasts with many other carcinomas such as breast cancer. Investigating the reasons underlying this unusual observation may provide important insight into the biology of colon cancer progression and putative novel therapy options.

Identification of seven novel germline mutations in the human E-cadherin (CDH1) gene

Hereditary diffuse gastric cancer (HDGC) is a cancer predisposition syndrome caused by germline mutation of the gene encoding the tumour-suppressor E-cadherin (CDH1). We describe the search for CDH1 mutations in 36 new diffuse gastric cancer families. All 16 CDH1 exons, neighbouring intronic sequence and an essential promoter region were screened by DNA sequencing. We detected nine different mutations, seven of which were novel. Of the seven novel mutations, five were identified in families who met the IGCLC clinical criteria for HDGC. Two mutations resulted in a premature stop codon and truncation of the protein. Three mutations affected splice sites; two of the splice-site mutations were shown by RT-PCR to disturb normal CDH1 splicing, while the third splice-site mutation was present in two unrelated HDGC families. The remaining two mutations resulted in amino acid substitutions and impaired the ability of E-cadherin protein to form cellular aggregates and suppress invasion in vitro. Together with the occurrence of extra-gastric tumours such as lobular breast and colorectal cancer, these findings further extend the types of CDH1 mutations and the spectrum of tumours associated with HDGC.

Single nucleotide polymorphisms (SNPs) at CDH1 promoter region in familial gastric cancer

INTRODUCTION

Gastric cancer is the most frequent gastrointestinal malignancy in Mexico and the proportion of patients younger than 40 years is one of the highest reported in the world literature. Recently several families with familial diffuse gastric cancer have been identified at the National Institute of Medical Sciences and Nutrition. Germline mutations in the E-cadherin gene (CHD1) have been described that result in the development of diffuse hereditary gastric cancer in young patients.

METHODS

The complete coding sequence at exons 1 to 16 and the promoter region of CDH1 was amplified by polymerase chain reaction in peripheral blood samples of two patients with early onset familial diffuse gastric cancer.

RESULTS

No germline inactivating mutations of CHD1 were found on either patient. Single nucleotide polymorphisms -160 C->A were detected in the promoter region of CDH1 in both patients.

CONCLUSIONS

The polymorphism -160 C->A theoretically confers an increased risk of developing diffuse gastric cancer. The relatives of these patients may an increased risk of gastric cancer among other tumors. There is presently not enough evidence to consider the -160 C->A polymorphism an etiologic factor of diffuse gastric cancer in these patients since the frequency and type of genetic alterations of CDH1 are largely unknown in the Mexican population. It will be necessary to conduct epidemiologic studies in the Mexican population to determine the influence that genetic alterations have on the genesis of diffuse gastric carcinoma.

Interleukin 1B gene (IL-1B) and interleukin 1 receptor antagonist gene (IL-1RN) polymorphisms in Helicobacter pylori-negative gastric cancer of intestinal and diffuse histotype

BACKGROUND

Polymorphisms in the interleukin 1beta gene (IL-1B-31T/C and IL-1B-511C/T single nucleotide changes) and in the interleukin 1 receptor anatagonist gene (IL-1RN2 variable number of tandem repeats) have been studied with respect to gastric cancer susceptibility. Available data support an aetiologic role of these genetic variants in the presence of concomitant Helicobacter pylori infection. Their contribution without H. pylori infection is still an open field of investigation.

MATERIALS AND METHODS

IL-1B and IL-1RN polymorphisms were investigated in 138 H. pylori-negative Italian patients with sporadic gastric cancer and 100 H. pylori-negative controls. Unconditional regression with odd ratios (OR) and 95% confidence intervals (CI), haplotype and linkage disequilibrium analyses were used to investigate the association of the polymorphisms with disease.

RESULTS

In all gastric cancer cases, carriers of the homozygous IL-1B-511T/T genotype showed a significant risk for the development of the disease (OR 3.2 with 95% CI 1.27-8.05). In cases with intestinal-type gastric cancer, however, both IL-1B-511T and IL-1RN2 alleles were associated with disease. In this subgroup, the odds ratio for carriers of both IL-1B-511T and IL-1RN2 was 6.49 (95% CI 2.07-20.4). Haplotype analysis supported the aetiologic contribution of these alleles in gastric cancer of the intestinal histotype.

CONCLUSIONS

In conclusion, IL-1B-511T and IL-1RN2 may contribute to intestinal gastric cancer risk in the absence of concomitant H. pylori infection. In this setting, future epidemiologic studies should consider dietary habits and exposure to carcinogens interacting with pro-inflammatory host genotypes.

The role of the E-cadherin gene (CDH1) in diffuse gastric cancer susceptibility: from the laboratory to clinical practice

Loss of function of the E-cadherin gene (CDH1) has been linked with diffuse gastric cancer susceptibility, and germline inactivating mutations in CDH1 characterise the hereditary diffuse gastric cancer (HDGC) syndrome. Hypermethylation in the CDH1 promoter region is a frequent phenomenon in poorly differentiated, diffuse gastric carcinomas and it was identified as the main mechanism for the inactivation of the remaining wild-type allele in HDGC cases. Specific criteria are used to identify patients with suspected HDGC and who should be investigated for CDH1 germline mutations. Accurate screening is mandatory for unaffected carriers of CDH1 mutations and selected high-risk individuals could be considered for prophylactic gastrectomy. Also, germline CDH1 mutations may predispose to lobular breast carcinoma and prostate cancer. Germline CDH1 mutations are not always detectable in patients who meet the HDGC criteria and the aetiological role of this gene is still under investigation. Families without recognised inactivating CDH1 mutations may have undisclosed CDH1 mutations or mutations in its regulatory sequences or germline mutations in unidentified genes that also contribute to the disease. In recent years, several germline missense CDH1 mutations have been identified, some of which showed a marked negative influence on E-cadherin function in experimental models. CDH1 promoter hypermethylation seems a key event in the carcinogenetic process of poorly differentiated, diffuse gastric cancer and it deserves further investigation as a new target for anticancer therapies with demethylating agents.

Expression of putative anticancer targets in familial adenomatous polyposis and its association with the APC mutation status

Several substances interfering with colorectal carcinogenesis may reduce or prevent adenoma formation in familial adenomatous polyposis (FAP), an inherited predisposition to colorectal cancer. This study determined the expression of genes coding for putative anticancer targets (COX-2, iNOS, MMP-7, ODC, PKCbeta, PPARgamma, RXRalpha, RXRbeta, RXRgamma) in FAP patients to provide one of the rationales for the design of chemotherapy and -prevention strategies. Gene expression was assessed by TaqMan analysis in colonic tissue of 9 FAP patients with mutations in the APC gene (APCpos), 5 FAP patients without identified genetic defect (APCneg), and 3 healthy individuals. Among the examined genes, PKCbeta and MMP-7 were most consistently altered in adenoma tissue relative to matched mucosa. Intriguingly, ODC was clearly overexpressed in polyps from APCpos but not APCneg patients. Furthermore, PKCbeta, MMP-7, ODC, and COX-2 as well as all RXRs displayed altered expression in apparently healthy FAP mucosa as opposed to that of healthy individuals. Our data suggests PKCbeta and MMP-7 to be the most suited as anticancer targets among the genes studied.

Cell cycle dependent DNA break increase in ataxia telangiectasia lymphoblasts after radiation exposure

The most striking feature of ataxia telangiectasia (AT) cells is their profound sensitivity to ionising radiation. A deficiency in the rejoining of radiation induced DNA breaks has been suggested to be responsible for AT radiosensitivity; however, the existing literature is controversial. A subpopulation, which is present in irradiated AT lymphoblasts, but rarely in controls, has been reported previously. The cells that make up this subpopulation harbour highly fragmented DNA and are responsible for the overall increase in DNA breaks soon after irradiation in AT lymphoblasts. This study examines the influence of the cell cycle on the highly damaged subpopulation. The frequency of highly damaged cells was highest when AT lymphoblasts were irradiated during the G2/M phase. In contrast, AT lymphoblasts irradiated during the G0/G1 phase displayed a frequency similar to control cells. Thus, only G2/M and to some extent S phase cells contribute to an increased DNA break number in AT lymphoblasts early after irradiation. These findings might explain several inconsistencies reported in the literature.

Germline alterations in the cyclooxygenase-2 gene are not associated with the development of extracolonic manifestations in a large swiss familial adenomatous polyposis kindred

Familial adenomatous polyposis (FAP) is an autosomal dominant condition leading to the development of multiple colorectal polyps and other features. Intrafamilial variation in phenotype is known to occur in FAP; despite carrying the same causing mutation in the APC gene, disease expression may considerably differ in affected individuals, likely due to the existence of modifier genes. Several lines of evidence suggest the cyclooxygenase-2 (COX-2) gene to be a candidate modifier in FAP. Since COX-2 appears to be expressed in tissues prone to be affected in FAP, it might influence the occurrence of extracolonic manifestations in this disorder. Herein, we investigated whether alterations in the COX-2 gene are involved in the development of extracolonic polyps and extragastrointestinal features. Mutational analysis using single-strand conformation polymorphism (SSCP) in 130 members of a FAP family displaying strong phenotype variation revealed 3 polymorphic sites within the coding region of the COX-2 gene. None of these allelic variants, however, segregated with a particular disease phenotype. In addition, expression analysis was performed in 31 family members with representative phenotypes. Neither of the two polymorphisms detected within the COX-2 promoter was associated with a given phenotype nor was there a significant difference in quality or quantity of COX-2 mRNA in lymphocytes as measured by reverse transcription- and real time quantitative reverse transcription PCR (RT-PCR and TaqMan). In conclusion, germline alterations in the COX-2 gene are unlikely to account for the development of extracolonic disease in FAP patients.

Increased levels of E2F-1-dependent DNA binding activity after UV- or gamma-irradiation

In mammalian cells, DNA damage induces robust changes in gene expression and these changes contribute to the proper execution of cellular responses to DNA damage, including DNA repair, cell cycle arrest and apoptosis. The transcription factor E2F-1 has been suggested to play a key role in the regulation of cell cycle-dependent gene expression and apoptosis. These activities depend on the ability of E2F-1 to form functionally active DNA binding complexes. Here we describe an assay that allows one to measure E2F-1 DNA binding activity in naive cells. We find that DNA damage, generated by UV- or gamma-irradiation, prompts increased production of E2F-1 DNA binding activity, which, at least in part, originates from alterations in E2F-1 protein levels. These findings represent an indication for a role of the transcription factor E2F-1 in the DNA damage response pathway.

Elevated frequency of p53-independent apoptosis after irradiation increases levels of DNA breaks in ataxia telangiectasia lymphoblasts

Ataxia telangiectasia is a recessive generic disease featuring cerebellar degeneration, developmental abnormalities, high cancer risk, immunodeficiency, and radiosensitivity. Increased levels of unrepaired DNA breaks have been observed in irradiated ataxia telangiectasia cells compared to normal cells but no specific DNA break rejoining rate deficiency has been defined. Alterations in radiation-induced p53-dependent apoptosis have been reported for ataxia telangiectasia cells. This study investigated the radiation response of ataxia telangiectasia lymphoblastoid cells using the comet assay and uncovered a new feature of this technique, namely its capacity to preferentially detect living cells. It is shown here that early after exposure to gamma-rays, ataxia telangiectasia lymphoblasts exhibit an elevated frequency of cells committed to die via apoptosis. The observed apoptosis, which is likely to be independent of p53, leads to a higher number of DNA breaks during the first 3 h post irradiation in ataxia telangiectasia cells, relative to controls. Apart from cells undergoing apoptosis, ataxia telangiectasia lymphoblasts have an identical capacity to rejoin radiation-induced DNA breaks as controls. Results suggest that p53-independent apoptosis may contribute to the radiosensitivity and the immune defects of ataxia telangiectasia patients.