The tumor-derived cytokine Chi3l1 induces neutrophil extracellular traps that promote T cell exclusion in triple-negative breast cancer

In triple-negative breast cancer (TNBC), stromal restriction of CD8+ T cells associates with poor clinical outcomes and lack of responsiveness to immune-checkpoint blockade (ICB). To identify mediators of T cell stromal restriction, we profiled murine breast tumors lacking the transcription factor Stat3, which is commonly hyperactive in breast cancers and promotes an immunosuppressive tumor microenvironment. Expression of the cytokine Chi3l1 was decreased in Stat3-/- tumors. CHI3L1 expression was elevated in human TNBCs and other solid tumors exhibiting T cell stromal restriction. Chi3l1 ablation in the polyoma virus middle T (PyMT) breast cancer model generated an anti-tumor immune response and delayed mammary tumor onset. These effects were associated with increased T cell tumor infiltration and improved response to ICB. Mechanistically, Chi3l1 promoted neutrophil recruitment and neutrophil extracellular trap formation, which blocked T cell infiltration. Our findings provide insight into the mechanism underlying stromal restriction of CD8+ T cells and suggest that targeting Chi3l1 may promote anti-tumor immunity in various tumor types.

HER2Δ16 Engages ENPP1 to Promote an Immune-Cold Microenvironment in Breast Cancer

The tumor-immune microenvironment (TIME) is a critical determinant of therapeutic response. However, the mechanisms regulating its modulation are not fully understood. HER2Δ16, an oncogenic splice variant of the HER2, has been implicated in breast cancer and other tumor types as a driver of tumorigenesis and metastasis. Nevertheless, the underlying mechanisms of HER2Δ16-mediated oncogenicity remain poorly understood. Here, we show that HER2∆16 expression is not exclusive to the clinically HER2+ subtype and associates with a poor clinical outcome in breast cancer. To understand how HER2 variants modulated the tumor microenvironment, we generated transgenic mouse models expressing either proto-oncogenic HER2 or HER2Δ16 in the mammary epithelium. We found that HER2∆16 tumors were immune cold, characterized by low immune infiltrate and an altered cytokine profile. Using an epithelial cell surface proteomic approach, we identified ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) as a functional regulator of the immune cold microenvironment. We generated a knock-in model of HER2Δ16 under the endogenous promoter to understand the role of Enpp1 in aggressive HER2+ breast cancer. Knockdown of Enpp1 in HER2Δ16-derived tumor cells resulted in decreased tumor growth, which correlated with increased T-cell infiltration. These findings suggest that HER2Δ16-dependent Enpp1 activation associates with aggressive HER2+ breast cancer through its immune modulatory function. Our study provides a better understanding of the mechanisms underlying HER2Δ16-mediated oncogenicity and highlights ENPP1 as a potential therapeutic target in aggressive HER2+ breast cancer.

Coordinated activation of c-Src and FOXM1 drives tumor cell proliferation and breast cancer progression

Activation of the tyrosine kinase c-Src promotes breast cancer progression and poor outcomes, yet the underlying mechanisms are incompletely understood. Here, we show that deleting c-Src abrogates the activity of Forkhead Box M1 (FOXM1), a master transcriptional regulator of the cell cycle, in a genetically engineered model mimicking the Luminal B molecular subtype of breast cancer. By phosphorylating it on two tyrosine residues, c-Src stimulates the nuclear localization of FOXM1 and the expression of its target genes, including key regulators of G2-M cell cycle progression as well as c-Src itself. This positive feedback loop drives proliferation in genetically engineered and patient-derived models of Luminal B-like breast cancer. Targeting this mechanism, including through novel compounds that destabilize the FOXM1 protein, induces G2-M cell cycle arrest and apoptosis, blocking tumor progression and impairing metastasis. We identify a positive correlation between FOXM1 and c-Src expression in human breast cancer and show that the expression of FOXM1 target genes predicts poor outcomes and associates with the Luminal B subtype, which responds poorly to approved therapies. These findings indicate that a regulatory network centered on c-Src and FOXM1 is a targetable vulnerability in aggressive luminal breast cancers.

Translational and HIF-1α-Dependent Metabolic Reprogramming Underpin Metabolic Plasticity and Responses to Kinase Inhibitors and Biguanides

There is increasing interest in therapeutically exploiting metabolic differences between normal and cancer cells. We show that kinase inhibitors (KIs) and biguanides synergistically and selectively target a variety of cancer cells. Synthesis of non-essential amino acids (NEAAs) aspartate, asparagine, and serine, as well as glutamine metabolism, are major determinants of the efficacy of KI/biguanide combinations. The mTORC1/4E-BP axis regulates aspartate, asparagine, and serine synthesis by modulating mRNA translation, while ablation of 4E-BP1/2 substantially decreases sensitivity of breast cancer and melanoma cells to KI/biguanide combinations. Efficacy of the KI/biguanide combinations is also determined by HIF-1α-dependent perturbations in glutamine metabolism, which were observed in VHL-deficient renal cancer cells. This suggests that cancer cells display metabolic plasticity by engaging non-redundant adaptive mechanisms, which allows them to survive therapeutic insults that target cancer metabolism.

Elevated expression of DecR1 impairs ErbB2/Neu-induced mammary tumor development

Tumor cells utilize glucose as a primary energy source and require ongoing lipid biosynthesis for growth. Expression of DecR1, an auxiliary enzyme in the fatty acid beta-oxidation pathway, is significantly diminished in numerous spontaneous mammary tumor models and in primary human breast cancer. Moreover, ectopic expression of DecR1 in ErbB2/Neu-induced mammary tumor cells is sufficient to reduce levels of ErbB2/Neu expression and impair mammary tumor outgrowth. This correlates with a decreased proliferative index and reduced rates of de novo fatty acid synthesis in DecR1-expressing breast cancer cells. Although DecR1 expression does not affect glucose uptake in ErbB2/Neu-transformed cells, sustained expression of DecR1 protects mammary tumor cells from apoptotic cell death following glucose withdrawal. Moreover, expression of catalytically impaired DecR1 mutants in Neu-transformed breast cancer cells restored Neu expression levels and increased mammary tumorigenesis in vivo. These results argue that DecR1 is sufficient to limit breast cancer cell proliferation through its ability to limit the extent of oncogene expression and reduce steady-state levels of de novo fatty acid synthesis. Furthermore, DecR1-mediated suppression of tumorigenesis can be uncoupled from its effects on Neu expression. Thus, while downregulation of Neu expression may contribute to DecR1-mediated tumor suppression in certain cell types, this is not an obligate event in all Neu-transformed breast cancer cells.

Elongation of the femoral neck in Perthes disease

We present the long-term clinical and radiological results of a series of 168 young patients with unilateral Perthes disease who were treated in our department between 1989 and 1997, using a combined osteotomy in the longitudinal and horizontal axis of the proximal femur and elongation of the femoral neck. Surgical treatment was undertaken for any group II (Catterall's classification) patient, with the presence of two or more radiographic signs of the "head at risk" and the clinical sign of flexion with abduction, as well as for all cases classified by Catterall as groups III and IV. The surgical procedure we describe provided 147 radiologically and clinically normal hips in the short and long-term. However, in the long-term, 21 out of 168 patients presented with residual deformities such as shallow acetabulum, thickening of the acetabular floor, coxa magna, thicker and slightly shorter femoral neck. Thus for the vast majority of patients, the operation we describe here provided leg length equalisation and restored the working length of the abductors by maintaining the tip of the greater trochanter at the same level as on the unaffected side.

Parathyroid hormone-related peptide and survival of patients with cancer and hypercalcemia

PURPOSE

Parathyroid hormone-related peptide (PTHrP) is the predominant cause of malignancy-associated hypercalcemia. However, its prognostic utility is unclear. We aimed to determine the prognostic value of serum PTHrP levels in patients who had hypercalcemia associated with malignancy.

METHODS

In this prospective case series, we evaluated 76 patients with a diagnosis of cancer and hypercalcemia (serum calcium level >/=10.3 mg/dL on at least two occasions). PTHrP levels >/=1 pmol/L were considered elevated. We used multivariate Cox regression analysis to identify factors associated with mortality.

RESULTS

Fifty patients (66%) died during follow-up. In a multivariate analysis, higher pretreatment calcium levels and elevated PTHrP levels were associated with increased mortality, with effects of PTHrP varying by age (P = 0.03). Survival was associated with pretreatment calcium levels both in patients over 65 years of age (hazard ratio [HR] per mg/dL = 1.5; 95% confidence interval [CI]: 1.2 to 1.8; P <0.001) and in patients aged 65 years or less (HR = 1.3; 95% CI: 1.1 to 1.5; P = 0.003). Adjusted for pretreatment calcium levels, elevated PTHrP levels were associated with increased mortality in patients aged </=65 years (HR = 3.8; 95% CI: 1.6 to 8.8; P = 0.002), but not in older patients (HR = 0.7; 95% CI: 0.3 to 1.9; P = 0.51).

CONCLUSION

PTHrP is a useful prognostic factor in malignancy-associated hypercalcemia, at least in patients aged </=65 years.

Pamidronate prevents the development of skeletal metastasis in nude mice transplanted with human breast cancer cells by reducing tumor burden within bone

Pamidronate is used routinely in the treatment of established bone metastasis. However, pamidronate has not yet been assessed in the prevention of osteolytic bone metastasis and its precise mechanism of action in this disorder remains to be established. In the present study, pamidronate or vehicle alone was administered subcutaneously to nude mice either simultaneously or as post intracardiac injection of the human breast cancer MDA-MB-231 cells. Radiographs were used first to assess the presence of osteolytic bone metastases. Kaplan-Meier analysis demonstrated that animals treated with pamidronate early, but not late, showed a slower progression of bone metastases and hind limb paralysis than did vehicle-treated animals. Mann-Whitney analysis showed that only 44.4% of mice treated with pamidronate at the time of tumor cell inoculation developed bone metastases as compared to over 80% (p<0.05) of mice receiving vehicle alone. We then analyzed the number of bone lesions and their volume at time of sacrifice by bone histomorphometry. In contrast to X-ray analysis, morphometric analysis indicates that the number of lesions within bone was similar in pamidronate and vehicle-treated mice but that the lesions were significantly smaller and therefore, often not visible on radiographs. These results demonstrate that pamidronate is effective in reducing tumor burden in breast cancer metastatic to bone and is most effective as a preventative agent when administered closest in time to implantation of tumor cells. Our data also suggest that pamidronate acts mainly by inhibiting the growth of established bone metastatic lesions but has no effect on the metastatic spread itself.

Targeted disruption of the 25-hydroxyvitamin D3 1alpha-hydroxylase gene in ras-transformed keratinocytes demonstrates that locally produced 1alpha,25-dihydroxyvitamin D3 suppresses growth and induces differentiation in an autocrine fashion

It has been previously shown that keratinocytes express a high level of 25-hydroxyvitamin D(3) (25-OHD(3)) 1alpha-hydroxylase (1alpha-hydroxylase). 1alpha-Hydroxylase catalyzes the conversion of 25-OHD(3) to 1alpha,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)]. 1,25(OH)(2)D(3) is both antiproliferative (i.e., suppresses cell growth) and prodifferentiative (i.e., induces cell differentiation) in many cell types. We hypothesized that local production of 1,25(OH)(2)D(3) by keratinocytes may suppress their growth and induce their differentiation in an autocrine fashion. To test this hypothesis, we inactivated both 1alpha-hydroxylase alleles in a ras-transformed keratinocyte cell line, HPK1Aras, which typically produces squamous carcinoma in nude mice. To inactivate 1alpha-hydroxylase expression by HPK1Aras cells, we disrupted both alleles of the 1alpha-hydroxylase gene by homologous recombination. Lack of expression and activity of 1alpha-hydroxylase was confirmed by Northern blot analysis and detected conversion of 25-OHD(3) to 1,25(OH)(2)D(3). We then examined the effect of substrate 25-OHD(3) on parameters of growth and differentiation in the double knockout cell line as compared to wild-type HPK1Aras cells in vitro. It was found that 1alpha-hydroxylase inactivation blocked the antiproliferative and prodifferentiative effect of 25-OHD(3). These in vitro effects were further analyzed in vivo by injecting knockout or control cells subcutaneously in severely compromised immunodeficient mice. Tumor growth was accelerated and differentiation was inhibited in mice given injections of knockout cells as compared to control cells in the presence of substrate 25-OHD(3). Our results demonstrate, for the first time, that 1alpha-hydroxylase expression by keratinocytes plays an important role in autocrine growth and differentiation of these cells, and suggest that expression of this enzyme may modulate tumor growth in squamous carcinomas.

Use of signal specific receptor tyrosine kinase oncoproteins reveals that pathways downstream from Grb2 or Shc are sufficient for cell transformation and metastasis

Many human cancers have been associated with the deregulation of receptor tyrosine kinases (RTK). However, the individual contribution of receptor-associated signaling proteins in cellular transformation and metastasis is poorly understood. To examine the role of RTK activated signal transduction pathways to processes involved in cell transformation, we have exploited the oncogenic derivative of the Met RTK (Tpr-Met). Unlike other RTKs, twin tyrosine residues in the carboxy-terminal tail of the Met oncoprotein and receptor are required for all biological and transforming activities, and a mutant lacking these tyrosines is catalytically active but non transforming. Using this mutant we have inserted oligonucleotide cassettes, each encoding a binding site for a specific signaling protein derived from other RTKs. We have generated variant forms of the Tpr-Met oncoprotein with the ability to bind individually to the p85 subunit of PI3'K, PLCgamma, or to the Grb2 or Shc adaptor proteins. Variants that recruit the Shc or Grb2 adaptor proteins generated foci of morphologically transformed fibroblast cells and induced anchorage-independent growth, scattering of epithelial cells and experimental metastasis. In contrast, variants that bind and activate PI3'K or PLCgamma failed to generate readily detectable foci. Although cell lines expressing the PI3'K variant grew in soft-agar, these cells were non metastatic. Using this unique RTK oncoprotein model, we have established that Grb2 or Shc dependent signaling pathways are sufficient for cell transformation and metastatic spread.

Expression and regulation of parathyroid hormone-related peptide in normal and malignant melanocytes

We examined parathyroid hormone-related peptide (PTHrP) production and regulation in both normal human melanocytes and in a human amelanotic melanoma cell line (A375). Northern blot and immunocytochemical analysis demonstrated that both cultured A375 cells and normal human melanocytes express PTHrP, but A375 cells expressed much higher levels of the peptide. PTHrP secretory rate increased at least 10-fold after treatment with 10% fetal bovine serum (100.2 +/- 2.8 pmol/10(6) cells vs. basal <15 pmol/10(6) cells) in proliferating A375 cells but only twofold in confluent cells. Treatment of A375 cells with increasing concentrations of 1, 25-dihydroxyvitamin D(3) [1,25-(OH)(2)D(3)] or its low-calcemic analog EB-1089 revealed that EB-1089 was 10-fold more potent than 1, 25-(OH)(2)D(3) on inhibition of both cell proliferation and PTHrP expression. Furthermore, inoculation of A375 cells into the mammary fat pad of female severe combined immunodeficiency mice resulted in the development of hypercalcemia and elevated concentrations of plasma immunoreactive PTHrP in the absence of detectable skeletal metastases. Our study, therefore, demonstrates a stepwise increase in PTHrP expression when cells progress from normal to malignant phenotype and suggests that EB-1089 should be further evaluated as a therapeutic agent in human melanoma.

The vitamin D analogue EB 1089 prevents skeletal metastasis and prolongs survival time in nude mice transplanted with human breast cancer cells

1,25-Dihydroxyvitamin D has potent antiproliferative and anti-invasive properties in vitro in cancer cells. However, its calcemic effect in vivo limits its therapeutic applications. Here, we report the efficacy of EB 1089, a low calcemic analogue of vitamin D, on the development of osteolytic bone metastases after intracardiac injection of the human breast cancer cell line MDA-MB-231 in nude mice. Animals injected with tumor cells were implanted simultaneously with osmotic minipumps containing either EB 1089 or vehicle. Both groups remained normocalcemic for the duration of the experiment. The total number of bone metastases, the mean surface area of osteolytic lesions, and tumor burden within bone per animal were markedly decreased in EB1089-treated mice. Furthermore, longitudinal analysis revealed that mice treated with EB1089 displayed a marked increase in survival and developed fewer bone lesions and less hind limb paralysis over time as compared with untreated animals. These results suggest that EB1089 may be beneficial in the prevention of metastatic bone lesions associated with human breast cancer.

Reversal of hypercalcemia with the vitamin D analogue EB1089 in a human model of squamous cancer

EB1089, an analogue of 1,25 dihydroxyvitamin D with low calcemic activity is a potent inhibitor of parathyroid hormone-related peptide (PTHRP) production in vitro. The purpose of the present study was to determine whether EB1089 could reverse established hypercalcemia in BALB C nude mice implanted s.c. with a human epithelial cancer previously shown to produce high levels of PTHRP in vitro. Total plasma calcium was monitored before and after tumor development and increased steadily when the tumor reached > or =0.5 cm3. When total calcium was 22.85 mmol/liter, animals were treated with a constant infusion of EB1089 or vehicle alone for a period of 2 weeks. A significant and sustained reduction of plasma calcium from 3.2+/-0.1 to 2.7+/-0.08 (P < 0.01) mmol/liter was observed during infusion with EB1089. In contrast, calcium levels in vehicle-treated animals continued to rise during the infusion period. Tumor growth velocity also slowed significantly after the administration of EB1089 as compared with vehicle-treated animals. Plasma PTHRP levels measured at the end of the 2 weeks' infusion period were significantly lower in animals treated with EB1089 as compared with animals treated with vehicle alone (44+/-8 pg/ml versus 194+/-35 pg/ml, P < 0.001). These results, therefore, demonstrate that EB1089 can reverse established hypercalcemia in a human model of squamous cancer.

Changing patterns in advanced gastric carcinoma

A retrospective study on patients with gastric cancer during the periods 1984-88 (n = 63 patients) and 1989-93 (n = 59 patients) was made. The aim of the study was to assess any changing patterns in tumour distribution, surgical management and survival during the two periods. When the diagnosis was made, the majority of tumours were advanced: 58 were stage IV and 21 were stage IIIB, with 43 tumours at earlier stages. The incidence of proximally located gastric adenocarcinomas increased from 15.9 to 27.1%, while the incidence of carcinomas located in the body decreased from 34.9 to 23.7%. The majority of patients underwent conservative gastrectomy. The proportion of proximal gastrectomies increased from 3.2 to 15.3 per cent (p = 0.02), whereas the proportion of combined resection of adjacent organs decreased from 38.1 to 22.0 per cent (p = 0.04). Perioperative mortality rate decreased from 17.5 to 1.7 per cent (p = 0.003). Prognosis remained unchanged in the two periods; overall 5-year survival is calculated as 12 per cent.

Parathyroid-hormone-related peptide in hematologic malignancies

PURPOSE

To determine whether parathyroid-hormone-related peptide (PTHRP) is an important pathogenetic mediator of hypercalcemia in patients with hematologic malignancies.

PATIENTS AND METHODS

We conducted a cohort analytic study in 76 consecutive patients with non-Hodgkin's lymphoma (NHL), Hodgkin's disease, multiple myeloma, and Waldenstrom's macroglobulinemia, 14 of which were hypercalcemic. Thirty normal subjects served as a control group.

RESULTS

Using the NH2 -terminal radioimmunoassay, PTHRP concentrations in heavy controls were undetectable (<7.5 pmol equivalents of PTHRP [fragment 1-34] per liter). The majority of hypercalcemic patients (8/14) had non-Hodgkin's lymphoma, and 62.5% of these (5/8) had significant elevations of circulating PTHRP concentrations (mean 70.5 +/- 38.5 pmol equivalents of PTHRP per liter) (P <0.01). In non-Hodgkin's lymphoma, 11 of 30 patients with advanced disease (stage IV) had elevated PTHRP concentrations, and of these, 8 of 11 had high-grade pathology. In contrast, only 3 or 21 patients with less advanced disease (stage I to III) had elevated PTHRP concentrations. In 4 NHL patients with less advance PTHRP concentrations sampled prior to cytotoxic chemotherapy, tumor response was associated with a decrease in PTHRP. Concomitant suppression of 1,25(OH)2D3 concentrations was observed in 66% of hypercalcemic patients with non-Hodgkin's lymphoma.

CONCLUSIONS

These results suggest that PTHRP may be an important pathogenetic factor in the development of hypercalcemia in hematologic malignancies, notably in non-Hodgkin's lymphoma.

Cystic angiomatosis of bone: a case report

Diffuse skeletal cystic angiomatosis is an extremely rare disorder that has not previously been reported in detail in the dental literature. This case report deals with the oral manifestations in a 10-year-old boy. Clinical, radiographic, and computed tomographic examinations showed hyperplasia of the right side of the face. The computed tomographic imaging studies revealed the extent of the jawbone lesions and the adjacent hyperplastic soft tissues. The histologic appearance of the lesions, the course of the disease, and the differential diagnosis are discussed.

Vitamin D analogs: new therapeutic agents for the treatment of squamous cancer and its associated hypercalcemia

We have examined the in vitro effects of 1,25 dihydroxy-vitamin D3 [1,25(OH)2D3] and of two side-chain modified analogs of 1,25(OH)2D3 (EB1089 and MC903) on cell growth and parathyroid hormone related peptide (PTHRP) production in immortalized (HPK1A) and neoplastic (HPK1A-ras) keratinocytes. Cell proliferation was strongly inhibited by 1,25(OH)2D3 and its analogs in HPK1A cells, and in this system EB1089 was 10-100 times more potent than 1,25(OH)2D3 or MC903. A similar effect on cell proliferation was observed in HPK1A-ras cells; however, 10-fold higher concentrations of 1,25(OH)2D3 or its analogs were required. We also observed a strong and dose-dependent inhibitory effect of these compounds on PTHRP secretion and gene expression. In both immortalized and neoplastic keratinocytes, EB1089 was 10-100 times more potent than 1,25(OH)2D3 or MC903 on inhibiting PTHRP production. However, although effective in HPK1A-ras cells, 10-fold higher concentrations of 1,25(OH)2D3 or its analogs were required to produce similar actions in this neoplastic model. These studies therefore demonstrate that a 1,25(OH)2D3 analog with low calcemic potency in vivo (EB1089) can inhibit keratinocyte proliferation and PTHRP production by such cells with greater potency than 1,25(OH)2D3. The observed effects of such analogs in neoplastic keratinocytes predicts their potential usefulness in vivo in inhibiting squamous cancer growth and its associated hypercalcemia.

Fractures of the medial condyle of the humerus in childhood

Fifteen cases of medial humeral condylar fracture are presented. Average patient age was 9.5 years, and the follow-up period ranged from 1 to 3 years. This type of fracture is very rare, and it seldom appears in the international literature. Treatment in our cases was based on the displaced or undisplaced nature of the fragment, i.e., the displaced fractures were operated on and fixed with Kirschner wires, whereas the undisplaced ones were immobilized in plaster casts. The treatment of choice in our series gave quite satisfactory results.

Ipsilateral injuries of the elbow and forearm in children

Fracture of the forearm with ipsilateral injury of the elbow joint is a rare traumatic entity in children. Twenty-four such cases were treated in our clinic during the last 4 years (1981-1984). The treatment was surgical in six cases and related to the elbow injuries, while the forearm underwent closed treatment. The results of these cases, regardless of treatment and severity of the injury, did not differ appreciably from the results of common forearm or elbow injuries.