Acid-adapted cancer cells alkalinize their cytoplasm by degrading the acid-loading membrane transporter anion exchanger 2, SLC4A2.

Acidic environments reduce the intracellular pH (pHi) of most cells to levels that are sub-optimal for growth and cellular functions. Yet, cancers maintain an alkaline cytoplasm despite low extracellular pH (pHe). Raised pHi is thought to be beneficial for tumor progression and invasiveness. However, the transport mechanisms underpinning this adaptation have not been studied systematically. Here, we characterize the pHe-pHi relationship in 66 colorectal cancer cell lines and identify the acid-loading anion exchanger 2 (AE2, SLC4A2) as a regulator of resting pHi. Cells adapt to chronic extracellular acidosis by degrading AE2 protein, which raises pHi and reduces acid sensitivity of growth. Acidity inhibits mTOR signaling, which stimulates lysosomal function and AE2 degradation, a process reversed by bafilomycin A1. We identify AE2 degradation as a mechanism for maintaining a conducive pHi in tumors. As an adaptive mechanism, inhibiting lysosomal degradation of AE2 is a potential therapeutic target.

Na-Cl Co-transporter (NCC) gene inactivation is associated with improved bone microstructure.

Gitelman syndrome (GS) is the disease model of the inactivation of thiazide-sensitive sodium chloride cotransporter (NCC), which is believed to benefit bone mass and reduce fracture risk. In this study, we found that GS patients have superior bone microarchitecture, which is associated with the disease status. Several decreased bone parameters with aging in healthy controls were reversed in GS patients to a certain extent. PURPOSE: To evaluate the impact of the inactivation of NCC on bone turnover and microarchitecture in Gitelman syndrome patients. METHODS: A cross-sectional study was conducted in 45 GS patients (25 males and 20 females). Serum procollagen type 1 N-terminal propeptide (P1NP), ß-carboxy-terminal crosslinked telopeptide of type 1 collagen (ß-CTX), and osteocalcin were measured. High-resolution peripheral quantitative computed tomography (HR-pQCT) was conducted to evaluate bone microarchitecture in GS patients and age- and sex-matched healthy controls. Areal bone mineral density (aBMD) was measured by dual-energy X-ray absorptiometry (DXA) simultaneously. RESULTS: GS patients had a relatively lower level of ß-CTX. aBMD at several skeletal sites was improved in GS patients. HR-pQCT assessment revealed that GS patients had slightly thinner but significantly more compact trabecular bone (increased trabecular number and decreased thickness), notably decreased cortical porosity, and increased volume BMD (vBMD) at both the radius and tibia compared with controls. The disease severity, represented as the relationship with the minimum level of magnesium during the course and standard base excess, was associated with bone microarchitecture parameters after adjusting for age, sex, and BMI. The decreased vBMD and Tb.BV/TV, and increased Tb.Sp and Ct.Po with aging, were reversed in GS patients to a certain extent. CONCLUSION: GS patients have superior bone microarchitecture, which suggests that the inactivation of NCC might be beneficial for avoiding osteoporosis.

Non-doctoral factors influencing the surgical choice of Chinese patients with breast cancer who were eligible for breast-conserving surgery.

BACKGROUND: The rate of breast-conserving surgery (BCS) is low in China. Many patients choose mastectomy even when informed that there is no difference in the overall survival rate compared with that of BCS plus radiotherapy. This study aimed to investigate the factors that influenced the surgical choice in patients eligible for BCS. METHODS: Female patients with breast carcinoma were enrolled in a single center from March 2016 to January 2017. They made their own decision regarding the surgical approach. Univariate analysis was employed to determine the factors associated with the different breast surgical approaches. Significant factors (defined as P < 0.05) were then incorporated into multivariate logistic regression models to determine the factors that independently influenced patients' decision. RESULTS: Of the 271 patients included, 149 were eligible for BCS; 65 chose BCS and 84 chose mastectomy. On the basis of univariate analysis, patients with younger age, higher income and education, shorter admission to surgery interval, and shorter confirmed diagnosis to surgery interval were more likely to choose BCS than mastectomy (P < 0.05). Meanwhile, patients who resided in rural regions, did not have general medicare insurance, and were diagnosed with breast cancer preoperatively were more inclined to choose mastectomy than BCS (P < 0.05). The multivariate model revealed three independent influencing factors: age at diagnosis (P = 0.009), insurance status (P = 0.035), and confirmed diagnosis to surgery interval (P = 0.037). In addition, patients receiving neoadjuvant chemotherapy (NCT) were more inclined to choose mastectomy. CONCLUSION: Surgical choice of patients eligible for BCS was affected by several factors, and age at diagnosis, confirmed diagnosis to surgery interval, and insurance status were independent factors.

Efficacy of two-weekly nanoparticle albumin-bound paclitaxel as neoadjuvant chemotherapy for breast cancer.

Aim: Compare the two-weekly regimens of nanoparticle albumin-bound paclitaxel (nab-P) with solvent-based paclitaxel (sb-P) as neoadjuvant chemotherapy for breast cancer. Materials & methods: Patients (n = 162) with operable early breast cancer received four cycles of dose-dense epirubicin and cyclophosphamide followed by four two-weekly cycles of nab-P (n = 83) or sb-P (n = 79), with trastuzumab when needed. Results: Across all the patients, the ypT0 ypN0 and ypT0/is ypN0 pathological complete response rates in the nab-P group were not superior to those in the sb-P group. However, pathological complete response rates for triple-negative breast cancer were significantly better with nab-P than with sb-P. Meanwhile, nab-P also induced more peripheral sensory neuropathy. Conclusion: The two-weekly nab-P regimen is a good neoadjuvant chemotherapy choice for triple-negative breast cancer.

Tumor-induced osteomalacia.

Tumor-induced osteomalacia (TIO), also known as oncogenic osteomalacia, is a rare paraneoplastic syndrome characterized by hypophosphatemia resulting from decreased tubular phosphate reabsorption, with a low or inappropriately normal level of active vitamin D. The culprit tumors of TIO could produce fibroblast growth factor 23 which plays a role in regulating renal Pi handling and 25-hydroxyvitamin D 1α-hydroxylase activity. Chronic hypophosphatemia could eventually lead to inadequate bone mineralization, presenting as osteomalacia. The diagnosis should be considered when patients manifest as hypophosphatemia and osteomalacia, or rickets and needs to be differentiated from other disorders of phosphate metabolism, such as the inhereditary diseases like X-linked hypophosphataemic rickets, autosomal dominant hypophosphataemic rickets, autosomal recessive hypophosphataemic rickets and acquired diseases like vitamin D deficiency. Localization of responsible tumors could be rather difficult since the vast majority are very small and could be everywhere in the body. A combination of thorough physical examination, laboratory tests and imaging techniques should be applied and sometimes a venous sampling may come into handy. The technology of somatostatin-receptor functional scintigraphy markedly facilitates the localization of TIO tumor. Patients undergoing complete removal of the causative neoplasm generally have favorable prognoses while a few have been reported to suffer from recurrence and metastasis. For those undetectable or unresectable cases, phosphate supplements and active vitamin D should be administrated and curative intended radiotherapy or ablation is optional.